Planetary Radio • Mar 04, 2022

Space Policy Edition: Why are outer planets missions so expensive?

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Scott Bolton

Juno Principal Investigator and Associate Vice President of the Southwest Research Institute’s Science and Engineering Division

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Mark Wolverton

Science Journalist and Author

Casey dreier tps mars

Casey Dreier

Chief of Space Policy for The Planetary Society

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Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

It's the 50th anniversary of Pioneer 10, the first spacecraft to the outer planets. Pioneers 10 and 11 were scrappy, low-cost endeavors that blazed the path for future exploration. But the future has been expensive: outer planets missions are some of the priciest planetary probes in history. Can we get back to a pioneering spirit and increase the frequency of outer planet exploration? To find out, we talk with Mark Wolverton, author of “The Depths of Space: The Story of the Pioneer Probes,” and Scott Bolton, principal investigator for Juno, the most affordable Jupiter mission in decades. Casey and Mat also discuss the dynamic and tragic situation in Ukraine, and its implications for space.

Pioneer 10 at Jupiter
Pioneer 10 at Jupiter Artist’s depiction of the Pioneer 10 spacecraft encountering Jupiter.Image: NASA


Mat Kaplan: Welcome to the March 2022 Space Policy Edition of Planetary Radio. I'm Matt Kaplan, the host of Planetary Radio, the weekly show, joined by our co-host for SPE, Casey Dreier. The Chief Advocate and senior Space Policy Advisor for The Planetary Society. Casey, welcome again.

Casey Dreier: Thanks, Matt.

Mat Kaplan: It's an interesting time we live in, isn't it, Casey?

Casey Dreier: Yeah. That's the nicest way I think we can say this, right? Like a lot of you, we've been watching what has been unfolding in this invasion of Ukraine with a mix of horror and I'd say, to some degree despair. Seeing this destabilization of the post World War II global order. The idea of seeing a massive land invasion in Europe is not something I ever expected to see. It's heartbreaking and wrenching to see the images coming out of Ukraine. Obviously, none of us know what will be happening there. We will talk a little bit here about some of the impacts to space in that little corner of the world. But at the end of the day, tens of thousands, if not hundreds of thousands of people will suffer greatly for this, and it's just a terrible situation.

Mat Kaplan: My feelings exactly. We will remind you that this program, even though we talk about Earth-bound issues, like space policy, our eyes are on the sky, and there is a big universe out there. And that's what The Planetary Society is all about, of course, so I will just mention one time briefly in passing, if you'd like to learn more about what we do, it's all at And of course, we would welcome you, as a member of the society.

Casey Dreier: Matt, that's something that I've been stewing in my head, this idea and how we talk about this right now, obviously, when it just seems like there's so many terrible things happening in the world. And I think now more than ever, we need to invest in what our best values are, curiosity, the scientifically motivated exploration of our natural world and ways to do that, that drive peaceful cooperation. Space always represents what's best in us. And when things are awful in the world, we so badly need to focus on what we can do. This is how I think about this role and how I hope our members think about engaging with The Planetary Society. And why this still matters, we cannot give up what makes us proud to be humans.

Casey Dreier: I remember one of my favorite Carl Sagan passages, obviously the Pale Blue Dot, but this is a slightly different one. He was talking about looking forward to the people who do go on to settle other planets and other stars that they will be like us, but with more of our strengths and fewer of our weaknesses. They will not be us exactly. Thinking about this long arc of our species history and hoping so badly that that's true. This is the time to embrace our strengths when we are so exposed to our weaknesses.

Mat Kaplan: That arc that bends we hope toward justice and perhaps also to discovery. Casey, before we go on from there, I want to acknowledge that we're recording this as you are making final preparations for the Day of Action, which is moving forward, isn't it?

Casey Dreier: It is. It will be next week. And we have nearly 150 members of The Planetary Society signed up. And again, we're really looking at this as an opportunity to say, despite everything else happening, this is the time to invest in what's best in us. for people to follow along or to learn more about it for this year or next. We have to adapt and engage with the world around us, no matter what. And this is no exception. So, this is an opportunity, I think, to very much engage on this better aspects of our nature.

Mat Kaplan: We're going to talk in a moment about some of the ramifications of what we see happening in Europe, in Ukraine for the stuff that we usually talk about space exploration, space development. Before that, Casey, give folks an idea of the main topic today and an idea of about who these two outstanding guests are. Because I think these are two of my all time favorite conversations you've had with people on SPE.

Casey Dreier: Well, speaking of our better angels of our nature, this is the 50th anniversary of the launch of Pioneer 10, the very first space probe beyond Mars, beyond the asteroid belt to Jupiter and the first space probe to leave our solar system. I've always been a super fan of the Pioneer 10 and 11 spacecraft. The little scrappy missions that literally pioneered a path to the outer planets for Voyager and others.

Casey Dreier: And this was a great time to talk about them and also put them in this broader context. Why don't we see more missions like these scrappy little ones to the outer planets or conversely, why do we see so few? We've only ever done anybody in the entire world, eight missions to the outer planets. Half of those missions happened in the 1970s, so why is that the case? And we're seeing a few more starting to trickle in, but fundamentally, they're very expensive. So, we explore why our outer planets missions tend to be so costly and how did Pioneer break that paradigm?

Casey Dreier: With us a special guest, Scott Bolton, the PI of Juno, the only other outer planetary mission to currently break that cost paradigm. And we also have the author of a great book on the history of the Pioneer spacecraft, Mark Wolverton.

Mat Kaplan: Okay. I think people are going to enjoy these conversations, as I said, as much as I did. Let's turn to the news. And I've actually been kind of surprised at how much reporting there has been about how what is happening in Ukraine and the reaction to it around the world may affect what's happening in space exploration. And there are some pretty substantial effects. Let's start with where there are people living right now, the International Space Station.

Casey Dreier: Right. We're seeing this discussion rise very rapidly. Because of this, I think global awareness of the importance strategically and symbolically of space, right? And all the activity we've been seeing in space has just increased the overall attention into the public sphere and beyond us, just space fans. The ISS, obviously, is a collaboration between 15 nations, including the US and Russia. It continues, as far as we know. As we're recording this, things have been changing very dynamically, but it continues as planned. It is a very tight integration on the space station.

Casey Dreier: I think it would be very difficult and time consuming. It seems like it could be done to separate the US and Russian segments of the station, but it's not something you just flip a switch and do. The space retains its symbolic power. The symbolism of the physical separation of the Russian and US segments, obviously, will be a very powerful and very strong statement on behalf of the ISS. NASA has emphasized that business continues as normal. They have been very low key and not making strong statements about the broader invasion of Ukraine.

Casey Dreier: You are not seeing that by the head of the Russian space program, Dmitry Rogozin who has a history of making somewhat [inaudible 00:07:50] and dramatic claims that had not always followed through. So, we've seen not threats exactly, but kind of a, "Hey, nice station here. Shame if anything happened to it. And good luck getting up into space." But it's just, we can't take those necessarily super seriously yet. Though, we are beginning to see, I think there's no doubt there's an increase in tensions. But most of the consequences are really happening to the European-Russian collaborations.

Casey Dreier: ISS, again, I think, because of its tight integration and frankly, at the end of the day, the Russians have no other space program to fall back on. The ISS is it for them. They don't have any other spacecraft ready to go. I'm trying to think of the last time they sent a scientific mission into space. The US has many, many, many more options here, as does the US allies and partners in space than the Russians do. And so, to step away from the station poses a huge risk for them, assuming they can pull off their station, there's a lot of who knows what kind of issues could happen with it. They could always just fly astronauts in Soyuz. They have more to lose from this separation than the US does.

Mat Kaplan: There is an American up there right now, who's supposed to come home late this month and he's supposed to come home on the Soyuz.

Casey Dreier: Mark Vande Hei, yeah.

Mat Kaplan: That obviously sends the mind into other places. Difficult to imagine that that wouldn't happen. But I'm sure there are a lot of people very happy now that we have Crew Dragon. They've always been happy, but yet another reason to be grateful.

Casey Dreier: You cannot overstate how important it has been for NASA to have regained independent American access to the station. In this situation, it would be a very tough outcome and very tough decisions being presented and the Russians would have a serious piece of leverage. Because of Crew Dragon, that is not the case right now, which again belies the importance of this kind of investments. If you have a belligerent actor, they also can leverage over you if you create these tight integrations with them.

Casey Dreier: Other places we've seen more of actual repercussions, just on the US side, the Russian space program they pulled out of the somewhat on paper-only Venera-D follow-up Venus mission, which was nominally a Russian mission to Venus, which had NASA scientific participation on. That's now officially not happening. It wasn't, I don't think, really a serious program at the moment. The bigger issue is that they will no longer sell Russian RD-180 or 181 engines to the United States. Notably the RD-180s are used for Atlas V as the first stage or engines. And the RD-181s are used on the Antares rocket, which Northrop Grumman now owns and manages and launches cargo missions to the space station.

Casey Dreier: This was the other cargo program through the National Commercial Cargo program in addition to SpaceX to supply the station. Antares has really only ever been used for cargo. It hasn't really occupied or expanded out of market the way that Falcon 9 has. But NASA has a contract with them to deliver supplies and it sounds like there's may be enough sub engines for two more launches. But after that, that may be it. That's a much more serious situation. And the supply chain approach Orbital Sciences that Northrop Grumman took with the Antares is to assemble it from all sorts of different aerospace contractors internationally, including Ukraine, which provided structural support for the first stage. So, this may be the end of the Antares rocket. That's again, a notable fallout from this.

Casey Dreier: The Atlas V has already been scheduled for retirement as the United Launch Alliance has proceeded with the development of the Vulcan rocket. Notably, the Vulcan has not flown yet and it is currently waiting for those Blue Origin upper stage engines that has been delaying this project. So, there's no immediate fallback. But Tony Bruno, the CEO of United Launch Alliance, stated today that they took steps precautionary steps earlier last year to take advanced delivery by I believe something like 24 additional RD-180 engines, so they can launch an Atlas V basically through at the end of its planned service. So, the Atlas V seems to be okay that the Russians won't provide additional technical support on those engines. I think the technicians and engineers at ULA know those pretty well, so it's not a huge deal. But again, there's a lot happening very quickly and a lot of these tight integrations that we've come to expect in this post cold war era are falling apart quite quickly.

Mat Kaplan: There's one other mission, European and Russian mission that I know you were also looking forward to as I was, and I was very sad a couple of days ago, as we speak, to see that the already much delayed ExoMars Rover will probably not launch this year. Which of course means it's not going to launch for at least two more years, because that's how things work when you want to go to Mars. Very sad.

Casey Dreier: It is and that that mission has never caught a break. Obviously, there are many more tragedies coming out of Ukraine than the delay of ExoMars, but it's just one of those tertiary-quaternary consequences. Originally proposed as a dual mission with NASA and ISA launching on a NASA rocket. NASA pulled out of that mission in the early 2010s due to budget cuts, leaving Europe or ISA kind of scrambling for a partner. Russia stepped in. Russia was going to provide the launch system and the landing platform and a number of scientific instruments on the rover, so it's a number of very, again, very tight integrations, not just the launch vehicle for the ExoMars rover.

Casey Dreier: ISA has already said that they see very little chance it will launch as planned this year and to even launch in '24 if they have to redesign the new landing platform. And not to mention Ariane 6, the also delayed European upgraded rocket. I would be surprised if they could even launch in 2024 if they still commit to this mission, and it will likely take hundreds of millions more Euros to significantly redesign it and prepare it for again a different launcher and a different landing system. So, it's very dismal-looking immediate future for ExoMars unfortunately.

Casey Dreier: Which again has these interesting repercussions because that was going to be ISA's demonstration, technological demonstration to NASA that it can operate a rover on Mars because ISA is building the sample collection rover that will be used as a critical path function to return these samples that Perseverance is picking up now for the Mars sample return campaign. How will that change NASA's calculations on whether it can rely on ISA as this critical path partner to make a rover if this will be their very first time operating a rover on Mars during this massive multi-billion dollar campaign. So again, lots of unknown questions, consequences coming out of this, the collapse of partnership.

Mat Kaplan: Toss a stone in the water and you're going to make waves all over the place. As Casey said, we will, I'm sure, have more to say about this, because we will know a lot more a month from now, when we bring you the April 2022 Space Policy Edition. For now, though, Casey, let's go on to that much happier topic. Marking that 50th anniversary that you mentioned to us with these two great conversations that are coming up.

Casey Dreier: Pioneer 10, Pioneer 11, these were space probes that first went to Jupiter and then Pioneer 11 went to Jupiter and then Saturn taking this beautiful arcing path over the plane of the solar system in the late '70s. Both were seen as Pathfinders basically to say, "Could we even get through the asteroid belt? Can we communicate with spacecraft that far away? Can we survive the radiation environment in Jupiter?" All of these things fed into the design of the much more famous, much more well-known Voyager spacecraft.

Casey Dreier: Something with the Pioneers always struck me because they were so hardy and they communicated. It ended up communicating with these little spacecraft for 30, I think 35 years after they were first built as they were far out of the solar system. They barely had a camera. They had very rudimentary systems on them. Again, they just were built like little tanks.

Casey Dreier: And something struck me once when I was putting together our Planetary Science budget data set that that contains the costs of every single NASA planetary mission ever made, I noticed and I was really surprised to find out that the Pioneers were made for at that time, two of them for $100 million. That's pretty cheap in the very late '69 to '72. And if you adjust that, for inflation, it comes out to just a shade under a billion dollars for two spacecraft with two launches included in that. These are what we would consider discovery class missions. They are by a long shot, the most affordable spacecraft we have ever sent to the outer planets.

Casey Dreier: Foot forward to the other side of this, The Planetary Society, as many of you know, have been working to support the Europa Clipper mission for over 10 years now. That mission was downgraded in the Decadal Survey, the scientific consensus report for priorities this decade. It did not hit the number one slot because it was seen as being too expensive. And it was estimated at that early design phase to be about $4.7 billion and they said, "This is far too expensive for a balance program, you have to cut it down." The Europa Clipper was the outcome of that. Instead of orbiting Europa, you fly by. You do all these other cost saving measures. They're using solar panels instead of plutonium. But we just found out as they've been building this spacecraft now, it's going to be a $4.2 billion mission.

Casey Dreier: It kind of goes to the point I was looking at this compared to other planetary missions. It turns out some of the most expensive planetary spacecraft ever, they're all outer planet missions. Cassini is the next most expensive at about $3.4 billion. These are all adjusted for inflation. Cassini about $3.4 billion to make, not even to operate. Galileo was about $2.7 billion to make, not to operate. And Voyager came out to be about $2 billion, actually pretty affordable for two spacecraft. So, if every outer planet mission costs $2 to $4 billion, you're just never going to have that many outer planet missions. And again, these do not include the costs of long-term operations.

Casey Dreier: I wanted to explore this. So, how could Pioneer pull off a low cost mission when Cassini and Voyager couldn't? The implications being if we want to have these more missions, what can we learn from low-cost missions? And this is what led me to talk to both Mark Wolverton, who literally wrote the book on the history of the Pioneer missions and Scott Bolton who defied this cost paradigm with the Juno mission, which was a new Frontier's class. It's called competed, which means that people had to compete and propose a coherent mission, which was then selected competitively among other priorities, back 15 years ago. That mission came out to be less than half the cost of Galileo at about $1.1 billion to build, adjusted for inflation.

Casey Dreier: What do we learn from something like Pioneer, not just from its pioneering approach to getting to the outer planets, but also its pioneering approach to cost savings? Do we have the right incentive structures for how we select and prioritize outer planet missions? If we can lower the cost of outer planetary missions, we can maybe get more of them the way that we've had these ongoing campaigns of midsized missions at Mars that can create these larger ecosystems of feed forward discovery, engineering talent and capability. We'll start with Mark Wolverton, the author of the book, The Depths of Space: The History of the Pioneer Space Probes, about how Pioneer was done so cheaply and quickly and what lessons we can take from that.

Casey Dreier: Mark Wolverton, thank you for joining us today on the Space Policy Edition.

Mark Wolverton: My pleasure, Casey.

Casey Dreier: So, I want to start big picture and I'll just give this away to the audience. I love Pioneer 10 and 11. I've always been a fan of these spacecraft. So, you don't have to convince me, but for everyone else, perhaps, what makes Pioneer 10 and 11 special? What drove you to write a whole book about these two little probes?

Mark Wolverton: I asked myself that question the other day when I was getting ready to do this interview, because it's something I hadn't thought about for a long time. And I thought, "Well, why did I?" Because I first actually written an article for American Heritage Invention and Technology magazine on Pioneer 10 then I kind of grew that into the book, The Depths of Space. I was just a young kid. But I remember very well when Pioneer 10 and 11 were happening was in this space, I was in a space team. But at that point, I did not think of writing a book about it.

Mark Wolverton: I think it's just the fact that they were indeed pioneers. They are aptly named. Many people, I think, even now don't realize this when I talk to people that the Pioneers are about space in general. Everybody knows about Voyager. But a lot of people don't realize that Pioneer 10 was the first spacecraft to venture beyond Mars, to go through the asteroid belt, to go to Jupiter. And its sister craft, Pioneer 11 was the first to go to Saturn and they both became the first spacecraft to exit the solar system, depending on how you define the boundary of the solar system. That's an issue for some debate among scientists. But yeah, they were the first.

Mark Wolverton: So, for that reason and also, I have in my mind, this image and I'm sure you do, too, being a fan of the spacecraft, of these small spacecraft out there in the void drifting forever, now completely out of touch with Earth and the loneliness. There's a certain aesthetic quality to that, a certain poetry to that, that really appeals to me.

Casey Dreier: I would even go further and say there's an aesthetic quality to the spacecraft themselves that I've always really loved that partly is a function of their spin stabilized. So, instead of sitting still and being pointed around by little thrusters, they spin to stabilize, which keeps them simple. But because of that, they need to be, they had to have basic rotational symmetry to just stay evenly aligned. So, there's something very pleasing, even just looking at them.

Casey Dreier: And then added to it, I think there's this aspect of the scrappy underdog story that you cover so nicely in your story. That these missions, what struck me revisiting this, is that they were selected. They were officially approved by NASA in, I think, February of 1969. And the first one launches just a shade over three years later in March 2nd, when we're recording this, of '72, which is just spectacular. And it wasn't JPL making these, it was Ames. Can you talk a little bit about the underdog aspect of this, the team and why it was that Ames and not JPL where these actions originated?

Mark Wolverton: That was another thing that appealed to me about the whole subject. Back in 1999, I had done a Science Writing Fellowship at NASA Ames Research Center, which also gave me the chance to kind of learn more about Pioneer and the whole background and history of Ames Research Center, just outside of San Jose in California, Silicon Valley. Ames was one of the original centers. NASA was previously known as the National Advisory Committee for Aeronautics, which was founded back in the early 20th Century. There were several centers that were well-established. Ames was one of them.

Mark Wolverton: Ames was established in 1939 and they were doing aeronautical research. They were developing airplanes and engines and they're known for their wind tunnels and that sort of thing. And they became part of NASA when NASA was born in 1958. But even after that, they were known as, they were something of a backwater as far as NASA was concerned. They weren't as glamorous, certainly not as Kennedy Space Center or as the manned flight center in Houston became later on or Langley Research Center in Virginia. Ames was sort of a forgotten step shot among all the NASA research centers.

Mark Wolverton: If you have a space project, you would not have thought of Ames as a place to take it. The idea came from a man named Alfred Eggers, who was an administrator at Ames. And he thought, "The space program is going on, we should be a part of this in somehow." He wanted Ames to contribute in a way that was going to be somewhat more substantial than just doing just auxiliary research on reentry bodies and that sort of thing. He was testing them out after something, about that he had the idea to do with a series of solar probes. And he and his deputy, which a man named Charlie Hall, who was later to be seminal on the whole Pioneer program. They went to NASA headquarters and said, "We want to get into this space program. Everybody else is doing it, why not us?"

Mark Wolverton: They talked to a man at NASA Headquarters named Ed Cortright, who was Deputy Administrator for Space Sciences and he liked the idea. JPL, of course, then was the premier center for unmanned spaceflight. William Pickering was the head of it. They had launched the early explorers and other space probes at that time. They were the big dog on the block. There were some problems with JPL in the sense that JPL was not really officially part of NASA, it was part of Caltech. It was operated for NASA by Caltech. And because of that, they tend to be a little independent-minded and maybe not always take direction well from NASA headquarters and that sort of thing.

Mark Wolverton: So, Cortright kind of wanted to mix things up a bit and get other NASA centers involved in space program. The idea of these solar probes that Al Eggers brought to him was just dropped into his lap and thought, "Yeah, let's go with this. Let's do this." They put together portfolios and all and that became later Pioneer 6 through 9.

Casey Dreier: Which not a ton of people usually think about these days, but were really important kind of as the precursor story to Pioneer 10 and 11. I mean, these were, they were kind of dropped off at various points in Earth's orbit. And we eventually created this kind of solar observing network of this very hardy, there's no pictures or no images on these spacecraft. They're pretty hardy, and they lasted for decades. Some of them, too, right?

Mark Wolverton: Yeah.

Casey Dreier: I'm trying to kind of trace the story of where, because at the end of the day, Pioneer 10 and 11, were done, very affordably, for roughly the price of what a Discovery mission, half a billion dollars-ish each in today's dollars, which is very cheap for outer planets. And I don't think this would have happened if we hadn't seen these kind of practice runs. But also, I think, a sense of competition between Ames and JPL. With Ames, really, again, as you said, really wanting to establish itself.

Mark Wolverton: Yeah, yeah. Charlie Hall was given the directorship of this, the whole Pioneer program, then. And yeah, I mean, he had something to prove. He was an aeronautical engineer and very good one. He been working in wind tunnels at Ames his whole career up to that point. He wanted to do something different. He had the energy, he had the drive, and he had the vision to do it. Yeah, the Pioneer 6 through 9, they were really, in a sense, the first Space Weather Network that we had and those were the farthest spacecraft from the earth at that time, which was back in the early '60s. But Charlie Hall, they were kind of his training ground in some ways for what he later did on Pioneers 10 and 11 and Pioneer Venus, the other forgotten Pioneer.

Mark Wolverton: The idea was to do something that was simple, that was very reliable, something that was not going to be overly complicated because obviously once you launch a deep space craft, you can't go and fix it later if something goes wrong with it. And a lot of the management techniques, the design techniques, and a lot of the operational philosophies that were later used on 10 and 11 were developed on 6 through 9.

Casey Dreier: And also just to be clear, there are pioneers kind of 1 through 5 were completely unrelated. Air Force missions very, very beginning of the space age. So, 6 through 9 can be seen as this kind of group. And they're all built roughly the same. What's frightening to me is-

Mark Wolverton: They're all identical, yeah.

Casey Dreier: And again, I think this is kind of this key thing, so we're in the late 1960s, Apollo is happening. We're starting to get missions to Mars. We're getting missions to Venus. Other planets are out there, obviously, right? So, let's talk a little bit, how did we end up getting to Pioneer 10 and 11, instead of just doing the Voyager when they started coming to this idea, "Oh, wait. We're going to have this alignment of outer planets in the 1970s."

Mark Wolverton: Right, right. Yeah, the idea of the Grand Tour was just something that had been bandied about NASA. Which for those who don't know what that is, it was the planets of the outer solar system were going to be lined up in their orbits in such a way that one spacecraft could essentially visit them all using gravity assist to go from one to the other. That's a once in a lifetime opportunity. You have to take that when it comes or you miss it. So, there were ideas for various outer planets missions and the first obvious target after Mars is Jupiter. There are a number of proposals for Jupiter missions. Goddard Space Flight Center had one. JPL course had one.

Mark Wolverton: And at this point when these were being discussed at NASA headquarters and being presented, NASA Ames had the success of the of the earlier Pioneers 6 through 9 behind them to prove that they could do something like this. And do it successfully, do it in budget and do it well. They basically put together their own proposal. Charlie Hall put together a proposal and they were chosen to do the first trans-Mars mission through the asteroid belt to Jupiter. That was an enormous risk, because at this time, of course, nothing had gone past Mars. And nobody knew If a spacecraft could even make it through the asteroid belt. We did not know how dense it was. We didn't know if it was going to be destroyed by dust debris when it went through.

Casey Dreier: I mean, I think that's really important to remember, putting ourselves back into their shoes more 50 years ago, right? Just how old the technology, I mean, how improving the technology was, how new the challenges were. They didn't even, I mean, they had to think about how they were going to communicate with something that's far away, right?

Mark Wolverton: Yeah. Exactly.

Casey Dreier: You had mentioned this process. Once they decided Jupiter is the next logical step, you had places like Goddard, too, come in and they kind of pitched this way advanced ambitious mission. But I think this is an interesting point, because this is happening in the context of Apollo is ramping down at this point, NASA is starting to shift more towards robotics, but their big mission was Viking at this point. Viking is this Cadillac mission, taking up huge amounts, but it still as a project the most expensive planetary project. They made functionally five flight-worthy spacecraft for what we would consider about $7 billion today.

Casey Dreier: The scrappy team with a proven record from Ames comes in and said, "Hey, we'll do this kind of very targeted mission." And I think this is one of the key things and let me know if this strikes as resonant with you. Pioneer, it really lives up to its name in the sense that it's not a long-term settlement mission in equivalent, right? It's not some big science ambition. It's like it's literally, "Can we get here?" In the sense of like true pioneer, "Can we get through the asteroid belt? Can we survive the radiation environment at Jupiter?" In a sense, those were the two real mission goals of these. And so, you didn't want to do a big expensive spacecraft with it.

Mark Wolverton: Right. Right. You just wanted to in a way, you could call them proof of concept vehicles for deep space exploration. And yeah, I mean, it was-

Casey Dreier: They were like the Lewis and Clark.

Mark Wolverton: Exactly. They-

Casey Dreier: You're not going out there to make this big settlement or this big establishment, you're just, "Can we go out there and see what the deal is?" And then [crosstalk 00:32:40].

Mark Wolverton: They're the pathfinders. They lay the ground for others to follow, which is exactly what they did. And nowadays, we take this kind of thing for granted. We're sending probes to Jupiter and Saturn and Pluto and beyond and they're magnificent achievements, but we take it sort of for granted in some ways. In the late '60s, early '70s, as you say, Apollo is going on, things are being done for the first time. Everything is being done for the first time, which means that we don't know what we can do and we don't know all. We know what some of the dangers are, some of the things we have to watch out for, but in the end, the only way to find out if we can do this is to try to do it and that was the job of the Pioneers.

Casey Dreier: Constraints that were imposed on them both in cost and basic survivability, I think, caused this creativity that the scrappiness came out again. And rereading your book, the last couple of days, I was really struck by how similar Pioneer 10 and 11 really are to Pioneer 6 through 9. You can picture it in your head of these little spinning cylinders, which is basically with their little magnetometer sticking out, which is the first Pioneer Heliophysics missions. And you kind of just take out the solar panels. You just kind of square out, flatten out some of that instrument panel, and then just add a big dish to it. And then you have the same thing sticking out. That's basically the same concept if they just stretch out. Because they have a three year window to design, test and build these things, but weren't launched.

Mark Wolverton: Yeah. No time at all.

Casey Dreier: No time at all. And I think that really drove this simplicity. And that's what really struck me reading it, about how this commitment to keep the mission simple, just so we can get out there. And that seemed to resonate so many ways down the pike to make it simple and I think reliable is what you point out, really learning through that pioneer thing.

Mark Wolverton: Yeah. And that all came from Charlie Hall, the Pioneer project manager. Those were his credos. I mean, in the '90s, the model of NASA became faster, better, cheaper. Well, the people, all the people I talked to on Pioneer said, "Well, yeah, we were doing that back 30 years ago with Pioneer. We invented it." And it's true. With Charlie Hall, he just said, "We need to get the mission done. We don't need to make things overly complicated. We need to make sure that they work."

Mark Wolverton: And as you say, Pioneer 10 and 11 were really a natural outgrowth of evolution out of 6 and 9, not only in technical design, but also in the philosophy of operation and how the whole project was run. Missions were not designed to prove new technology. They were designed to accomplish a specific mission, meaning going into the asteroid belt going Jupiter. Anything that did not contribute to that was superfluous as far as Charlie Hall was concerned.

Casey Dreier: And something else you mentioned, I think is really important to this is how they approached in the science, too. You have this piece in your book about how the science team had to learn how to accept compromise, because if it's just the data, you just couldn't get enough data back. Everyone had their own instrument. And because I think, again, the constraints, these external constraints imposed on them, the goal of the mission wasn't to return the best data of every instrument no matter what. It was to return something back, which would be seen as better than nothing. Again, because there literally was no in situ data collection prior to this.

Casey Dreier: And so I think that forcing function seems to have a lot to do with keeping these types of missions focused, and therefore affordable, which then means you have these serving as true Pathfinders that then feed into Voyager, right? And Voyager design changes and adapts based on what Pioneer sent back.

Mark Wolverton: Absolutely. Yeah, yeah. As you say, these are the Pathfinders. They're not going to try to do complete explorations. They're not going to try to get the prettiest pictures of Jupiter and Saturn, any of that stuff. They're just going to try to prove that we can do this. And then use the knowledge, use the experience to do the Cassinis and the Galileos and everything else that follows. But to do that, you have to get there. You have to survive, you have to get through the asteroid belt. You have to survive through the radiation environment of Jupiter. All of that now and whatever other unknowns are out there that we don't know about because they're unknown.

Casey Dreier: I just cannot believe that this is true. That they don't even have computers on these spacecraft. Describe exactly what they have. I can't quite. It's like a register where they execute input, but there's no real logical computing on these spacecraft to keep them simple.

Mark Wolverton: Yeah. Well, I mean, these are built with 1960s technology, so integrated circuits, the electronics we have today are still science fiction. But even back then, integrated circuits really a lot of sophisticated solid state technology is still very new, very unproven, and exactly the kind of thing that you don't want to put on a vehicle you're sending millions of miles into space, and you can't repair or fix when it's gone. Yeah, just this, the shift registers they could store about like five commands, I think.

Mark Wolverton: That's another thing about the Pioneers, too, that fascinates me, the 10 and 11 They were literally flown from Earth. Spacecraft these days are very self-sufficient. Obviously, we do communicate with them all the time. We issue commands to them, but they can do a lot on their own out there in space. 10 and 11 did not have that. They had to be controlled from Earth. The signals were sent to them and whatever commands were executed, which was another reason why the issue of communications was so important. Which is another big issue I talked about in the book, the facilities of the Deep Space Network and allocating those resources.

Mark Wolverton: I have heard the Pioneers disparaged at times as, well, they were just, they were just shoestring. They were just simple. Well, yeah. And that's why they were so successful and that's why Voyager and everything else that followed was made possible.

Casey Dreier: What do you think the long term lessons are that you could see either NASA learning or the scientific community learning from that type of mission? How they built it? What they tried to do. What resonates with you, again, as this kind of long term, as you look back to these missions over the decades?

Mark Wolverton: Again, this is getting back to Charlie Hall's whole method of working, which is, "Keep it simple, stupid." And I think that is a credo that is in missions like these, it can be very effective, especially when you're doing it for the first time. You don't take chances with technology. Use something that you know is going to work, that you know is going to be reliable. That you've hopefully used before and a lot of the, some of the designs on Pioneers 10 and 11 were, as I said, outgrowths of things that have been done on 6 through 9.

Mark Wolverton: And also, the team, the scientists, you had some scientists on the scientific team that had never flown a deep space mission before. But you also had the real veterans. People like James Van Allen, who is basically the founder of American Space Science. John Simpson from the University of Chicago. These guys had flown on many missions before. They knew how to design instruments. They knew how to work around the constraints. They anticipated constraints. One of the key elements of Pioneer and another first for 10 and 11 was they were the first spacecraft to use the radioisotope thermoelectric generators, the RTGS. The nuclear power, basically for power, because they were going to be too far away from the sun for solar powers, solar cells to be efficient.

Mark Wolverton: John Simpson, without being told, he kind of anticipated that and designed his instrument around being able to work with that. It's having the good philosophy of the right tool for the right job and nothing more. And having a really good group of people that are used to working with constraints and know how to compromise and know how to get around things and know how to get things done.

Casey Dreier: You mentioned this earlier, why Pioneer hasn't captured the same role in our culture and imagination the way that the Voyagers did. And I think so much of it is probably the images, right? The pictures. Something that we can just resonate with whether or not we're a solar physicist or plasma physicist or that the detailed kind of instrumentation returns back that's hard to decipher. I wonder if that's a lesson, too, where your mark in cultural legacy will be visual or should be visual or has to be visual. And without that, and they did have a very rudimentary Imager on Pioneer and it did take the closest pictures we've ever seen of Saturn and Jupiter at that point, but it wasn't the greatest camera.

Mark Wolverton: No, no.

Casey Dreier: So, where do you think that that role in terms of designing a mission is their responsibility at the end of the day? Or if you're concerned about your legacy, maybe you should have a very nice camera on it no matter what?

Mark Wolverton: Well, yeah, I think that's a very important point. But of course, with Pioneer, Charlie Hall and the scientists, they weren't concerned about legacy. They were concerned about getting the mission done. And Pioneer 10 and 11, it wasn't really even a camera. It was something called the Imaging photo poll perimeter that will give you this sort of like slit-scan TV images, but certainly nothing like very pretty colorful pictures.

Mark Wolverton: It's kind of like in the earliest days of spaceflight where you get very excited when we would see pictures from high altitude rockets of the sea or the curvature of the earth. You could hardly see anything or tell what anything was, but just the fact that you were seeing that was exciting. Well, you get jaded very fast with that kind of thing. So yeah, I mean, I-

Casey Dreier: Did Pioneer win an Emmy?

Mark Wolverton: Yes. Some of the some of the Public Affairs presentation is that some of the scientists and some of them like again, like Van Allen and Simpson, who were very experienced in this kind of thing in the press conferences they would give and presentations on television. Yeah, they did win a Special Emmy, I think, for some of that.

Casey Dreier: For the Saturn, was it the Saturn Flyby or I forget. It was-

Mark Wolverton: I think Saturn, yeah. I'd have to-

Casey Dreier: Yeah. The live data coming.

Mark Wolverton: But yeah-

Casey Dreier: All right, so the Emmy Award winning team. [crosstalk 00:43:07].

Mark Wolverton: But yeah, but that's I think that's just in general among the public at large, the general public that's what it is. I think, Pioneer, they see the pictures from Jupiter, Saturn, and they're very kind of fuzzy, and not very pretty. And then they see the pictures from Voyager and they're spectacular, so those are going to be the ones that they remember. And that's just a very human thing and a very natural thing.

Mark Wolverton: Fortunately, now, imaging technology has advanced so much that we can get very pretty pictures much cheaper and easier than was possible back then. But yeah, I think it's definitely a factor as to why Pioneer it has not been remembered quite as well as the Voyagers.

Casey Dreier: Well, we'll do our work to push back on that.

Mark Wolverton: Can I just make one more final point?

Casey Dreier: Of course.

Mark Wolverton: I was just thinking about 1972 and the fact that, as we say, today, March 2nd as we record this is the 50th anniversary of the launch of Pioneer 10. Though 1972 began with what was at that time the first mission that would go farthest into space, he first unmanned mission. And it ended with the last lunar landing to date and also the last manned space mission where human beings were as far from the earth as they were at that time. There's sort of a yin and yang there, the farthest and the shortest and-

Casey Dreier: Yeah, that's true. The opening up of the outer solar system as we closed off our access to our nearest neighbor and Cislunar environment. That is a good interesting poetic point. And demonstrative I think of and the shift, too, that's also the year that the Space Shuttle was formally approved for development, was the early 1972. So, that was kind of this statement of retrenchment of human spaceflight to closer to home while we set our eyes further afield for our robotic probes.

Mark Wolverton: Of course, the Space Shuttle had something of a detrimental effect on unmanned [inaudible 00:45:02]. That's the toughest part now that the-

Casey Dreier: That's a different podcast. That's a different episode we'll have to talk about some time individually here. So, Mark Wolverton, author of the Depths of Space: The Story of the Pioneer Planetary Probes and other book. One on nuclear weapons, if I'm correct that you've released this book.

Mark Wolverton: Yeah. The new one that just came out this year is sort of a little primer on nuclear weapons. And unfortunately, it's turned out to be much more timely than I had hoped at that time, but-

Casey Dreier: Yep, we will link to your page and to your latest book. And, of course, the Pioneer book on the Show Page. And I recommend people to check out the Pioneer book. It's a lovely history and honors the legacy of the people, who put so much into these little scrappy pioneering probes that that we adore so much. Mark, thank you, again. I appreciate you being here.

Mark Wolverton: Thank you, Casey. It's been a pleasure.

Mat Kaplan: Author and historian Mark Wolverton talking with Casey Drier, Chief Advocate for The Planetary Society. Fascinating conversation, great insights into those two missions. I'm, like you, a super fan of those missions. I always wondered why I love Voyager because we all do. Why Pioneer just sort of faded into the background when they were such amazing accomplishments.

Mat Kaplan: There is one more little piece of the Pioneer 10, 11 missions that we should mention, because The Planetary Society had a big role in this and that was the pioneer anomaly. Which we learned, it turns out the physical laws of the universe are still intact. But it was still a fascinating little bit of research. We found out why these spacecraft were not exactly where we expected them to be. Casey?

Casey Dreier: Yeah, they were both, I think a little slower leaving the solar system than they "should have been," based on our predictions. All sorts of theories were proposed where it could be, ranging to as extreme as maybe we don't understand gravity correctly. But the answer, as always, is you just don't understand your thermal modeling as much, I think. But we found, our Society members funded and we found a bunch of old data sets. They read beautiful analysis. Really complex, close effort, mystery solving here by the Society and our colleagues working on this.

Casey Dreier: And the answer was, yeah, it's just a meeting of, I think, little extra photons in the direction that it's traveling. And so, it's slowing it down over time because of that. So, the answer is always, I think it's a good lesson for when you don't understand something. It's usually because you don't fully understand the system, not that the gravity is wrong. Gravity survives to pull another day.

Mat Kaplan: Somebody said something about extraordinary claims once.

Casey Dreier: There you go.

Mat Kaplan: All right. We're going to take a moment here to catch our breath, Casey and me. And take a very short break, less than a minute. We'll be back with Casey's conversation with the principal investigator for the Juno mission that is still revealing Jupiter, Scott Bolton.

Sarah Al-Ahmed: There's so much going on in the world of Space Science and Exploration, and we're here to share it with you. Hi, I'm Sarah, Digital Community Manager for The Planetary Society. Are you looking for a place to get more space? Catch the latest space exploration news, pretty planetary pictures, and Planetary Society publications on our social media channels. You can find The Planetary Society on Instagram, Twitter, YouTube, and Facebook. Make sure you like and subscribe, so you never miss the next exciting update from the world of Planetary Science.

Mat Kaplan: We're back. Casey, take us into this conversation with Scott Bolton of the Juno mission.

Casey Dreier: I think it's important to highlight, again, some of those key items that Mark and I talked about that really played into how Pioneer was able to deliver a spacecraft, again, in three years from concept to design, build, test and launch at this very low budget. And I think that some of the key things that really resonated me is simplicity of design, a strong project manager who has control, I think, over and insight into the entire competing set of goals in a mission. I think a really clear set of goals, right? A very focused set of goals of what you want to accomplish.

Casey Dreier: The other key thing was a science team willing to accept compromise, maybe not having the best data you could get, but taking an idea that everyone compromises a little bit, so you get something rather than nothing. And I think we may have mentioned. This is the idea of in a sense of better, faster, cheaper before that term existed in the '90s. This idea that you can do more missions for lower cost if you just kind of step down your peak of expectations. And this is an issue that has really been in my head a lot.

Casey Dreier: I think you've heard me on the show for the last year or so really kind of grappling with this idea. This balance of when the scientific community wants to set these really hard questions to answer and then they want to the best data possible to answer these big questions, that doesn't include things of cost or cadence or anything else. It becomes purely focused on the science. How do you balance that with some data is better than no data or lower cost commercial data from data providers? Getting anything versus something versus really defining everything around a central question. I don't have the answer for this, but I think this is continues that discussion.

Casey Dreier: Scott Bolton who put Juno together, again, was a competed mission. They had to fit within a billion dollar budget line, basically. They had to propose a way to get to Jupiter for a cost that no one had done before. But when you are running a new frontiers mission, you have, by a definition, this PI, his role, is the somewhat independent single point of responsibility. So, there's your strong project manager. New frontiers missions are more targeted science, so there's your strong constraints that help you drive compromise.

Casey Dreier: They get to assemble their team, before they even propose the mission. So they create an internal, strongly coherent scientific team that by definition is willing to work with each other on compromise versus compete with each other to get instruments on the mission. And because of this cost cap, there has to be a focus on reliability and simplicity. You kind of hear these echoes of how Scott Bolton approached making Juno work. Which again, this mission was built for, again, in today's dollars, about $1 billion, $1.1 billion, which is less than half of what it cost to build Galileo, and it's doing amazing science. And you'll hear Scott talk about how it's almost like a flagship mission at Jupiter once you're there.

Casey Dreier: Now, Scott does a lot of things. He's also on the Europa Clipper mission. We talk about that a lot. And I think it's not necessarily, we're not picking on Europa Clipper, but I see Europa Clipper as if every outer planets mission is $4 billion, you're just never going to have that many outer planets missions. And if the outer planets community wants to increase the cadence, wants to build the opportunities for outer planets science, there has to be a way to find these kinds of Juno-like compromise missions that can still return 80% of your mission goals, 75% of your mission goals versus 0% of them. Scott will walk us through his thoughts on that as well.

Mat Kaplan: It's a really terrific conversation. Let's go to that now. Casey talking with Scott Bolton, the Principal Investigator for Juno.

Casey Dreier: Dr. Scott Bolton, thanks for taking some time today to join us on the Space Policy Edition. We are recording this on the 50th anniversary of the launch of Pioneer 10. Again, we're using this as an example as a concept of study how we get out to the outer planets and the challenges of doing that from a fundamental, even cost level that you are intimately familiar with.

Casey Dreier: But first, before we jump into the nuts and bolts of that, can you help place Pioneer 10 and 11 in context, in the larger effort to understand the Jovian system and even just getting out to the outer planets. How did that impact you as a scientist and also as a project manager when you started moving forward with Juno?

Scott Bolton: Well, of course, Pioneer 10 and 11 kind of started it all, right? That was the first close-up look that we had of the outer planets. It kind of set the stage. Me, personally, I was already too young and didn't really, as I was growing up, I wasn't really aware of the Pioneers 10 and 11 results. I was, of course, busy watching Star Trek, but I didn't connect all of the NASA exploration yet. But it really did set things up and show us the giant planets close up and laid out some of the basic puzzles.

Scott Bolton: You have these giant planets much bigger than the Earth. How are they built? They're completely different. Balls of gas, not even with a solid surface underneath. Nobody knew yet. And so a, lot of the basic questions of even what is a giant planet was sort of set up by Pioneer 10 and 11. And our first views of Jupiter's spectacular atmosphere. This art show that goes on as the winds and clouds blow around in there. That was really the first view of it. So, I mean, they were really important. And of course, they motivated the follow-ups with Voyager and then eventually, Galileo, and even Cassini

Casey Dreier: Did Voyager basically completely blow out of the water the data collected by Pioneer. I'm kind of curious in this, because Pioneers are interesting in the sense that 10 and 11 are roughly the cost of what we would consider a Discovery class mission today. Just spectacularly affordable, but they're very simple spacecraft. You started working in the '80s at JPL, working on the Galileo mission. Was that even relevant at that point or did Voyager completely replace any data or insights taken by the pioneers?

Scott Bolton: No, I think, actually, Voyager was a natural follow on to Pioneer. And in some sense, the results from Pioneer motivated us to reach out again, although, people were probably already thinking of following it up. The Voyager was originally conceived of as this Grand Tour, where it was recognized by navigation experts and scientists that you could build something that might actually be able to visit Jupiter, Saturn, Uranus, and Neptune. That I think was sort of one of the basis of why Voyager was sent out.

Scott Bolton: And of course, technology had changed, so it had more advanced instrumentation. The interest in the giant planets was there, so that you went in and not only did you do Voyager 1 and 2, so you had a backup. But they threw very advanced cameras on it and other science instruments that really weren't available yet at Pioneer. Pioneer, I think was excellent, though. I would never say, I mean, for its day, it was incredible, but technology advances and our science questions evolve.

Scott Bolton: From my perspective, and I kind of came on the scene as a young scientist at JPL, just about at the time Voyager with was going by Saturn. I was still in school when at Jupiter and in fact, seeing the results from Jupiter from Voyager is part of the reason that I wanted to go with JPL, right? As somebody came and gave us a talk at my university and I was like, "Wow, they're trying to reach out as far as you can go." Of course, I wanted to live in the Star Trek world and travel around the galaxy, but nobody was doing that.

Scott Bolton: But my memory of Voyager is these incredible movies that showed Jupiter's stormy zones and belts, blowing around back and forth in different directions. And me realizing how incredible that planet must be. And then, of course, they did these incredible stuff with the moons and the magnetosphere, and then you had Saturn. And so, it just kept following up. I didn't get to do anything, really, with the Saturn Voyager, I was just there when it was happening. But I was young and really working engineering at that point. But by the time it got to Uranus and Neptune, I was already engaged a little bit with the science of Voyager. So, I got to experience that science team and be familiar with their science instrumentation.

Casey Dreier: So, do you think there's just a lower limit then of value? If you try to save too much money building a spacecraft, particularly to the outer planets, which, again, one of the predicates of this whole episode is that the top three most expensive planetary missions ever are outer planets missions. If you try to shave off too much thinking about Pioneer, not to dismiss their data. But it seems like Voyager was the type of data you needed and those are much more expensive missions. Is there just a level where it's not worth it, to invest in these missions? Is cost of necessary predicate to returning the type of data that actually gives us something to work with?

Scott Bolton: Yes, and you have to also fold in risk and the reliability factor. So, when you're dealing with something that costs a lot and takes a long time to get there, which the outer planets do, you would like to make the spacecraft and the flight system robust, so that you decrease within reason, the chances you're going to lose the mission, right? So, if we're just trying to go to Mars, I mean, it takes six months to get there. Nobody wants to lose that mission, but you could build another one and you didn't lose a generation waiting.

Scott Bolton: When you go to the outer planets, you're looking at travel times that are five to 10 years or longer. You need to invest enough that's commensurate with that kind of time investment in my view. Now, I do think there's a minimum and cost that's probably worth it in today's dollars, as I understand, the cost of doing the missions. But it's nowhere near the many billions of dollars that we experienced with Voyager, Galileo and Cassini. I think it's in the $500 to a billion-dollar range, ,$500 million to $1 billion and it's, you almost can reach out to the outer planets within the Discovery Program and you certainly can do it in New Frontiers, which Juno has already demonstrated.

Scott Bolton: And so, I think that's probably the threshold is somewhere between New Frontiers and Discovery. And it's probably a little bit more toward New Frontiers' budgets, which is somewhere near a billion dollars. It depends on whether you count the launch vehicle and you count all the Phase E expenses of operations, but you're somewhere in that realm in order to do it. And then I think the question that we have to really ask ourselves, which I think Juno was kind of posing to us is, is the difference between a New Frontiers mission and the classic flagship really worth it? Is it warranted to go from a billion or a billion and a half to $4 or $5 billion? And I'm not sure that's needed. And I think Juno has kind of demonstrated that you could do flagship type science, system-wide exploration within New Frontiers.

Casey Dreier: Tell me a little more then about how you approached cost containment for Juno that made it, can still such a successful and broad mission, it came in at less than half the cost of the just the development of Galileo, much less Cassini and other more expensive missions. How do you approach that to make that so affordable, relatively speaking?

Scott Bolton: Well, of course, the pressure was on us, right? Because we were proposing to a cost cap PI class mission, right? And so, we had to fit within the budget and what we were doing was exploring whether that was really possible. One of the approaches is maybe something that can only really be done in a PI class mode, because and I think that is an enabling aspect is that everything pyramids up to one principal investigator to make decisions that are across the science and engineering mission design risks, all of that, right? Partnerships, how you manage, how you kind of organize your management and chain of command and things like that.

Scott Bolton: Even though there's a NASA Center in this, in the case of Juno, there's JPL managing. They're really reporting to me, right? And I've set up something that has my science team listening to what's being reported and making the decisions. So, it really starts right from the beginning when you're first formulating the idea. And so, one of the advantage and I had a lot of experience and so did the colleagues that I was kind of first starting this with on Galileo and Cassini and Voyager. We had spent a lot of time on Galileo and Cassini with large science teams and large engineering teams, trying to figure out what to do and trying to fit inside a box.

Scott Bolton: And there was intrinsic inefficiencies associated just simply with the size. And the fact that the engineering and the management of it had a lot of control over how things went. Even though everybody recognized that the science was ultimately the motivation and driver. And so, what we did when we approached Juno is we tried to collapse all of our requirements and desires into one team that was synergistic. So, we created a mission where the science observations, the science goals and objectives, the actual sensor designs, what instruments we'd have. The spacecraft design and how those instruments would be able to observe. The mission design, which was how the orbit would work. That was all synergistically blended right from Day 1.

Scott Bolton: And we explored all the options. Do we make this a spinner? Should we make it three axes stabilize? Can we make it nuclear powered? Can we do this with solar power? All of these fundamental questions. How do we deal with the radiation? Can I make a single vault and I mean, the idea of putting in a radiation vault was really, for efficiency reasons. It may have not been the best way to do it, if I was trying to minimize the mass, which often a spacecraft team is trying to do.

Scott Bolton: Instead, I looked at it and said, "What we need to do is minimize the analysis and all of the engineering required to satisfy the radiation, even if it's at the expense of a little bit of mass because it's going to be so much easier if I can just build these walls of titanium." Of course, in the beginning, I thought there were going to be walls of tantalum. And just put everybody in the same box. Initially, JPL came back and said, "That's really inefficient. You're better off putting boxes around every little thing." And I said, "But then I have to analyze all of those, right? It wasn't cost effective."

Scott Bolton: The same thing with the spinner, could we design something where everybody looked out between the solar rays. And you sat around with the science teams, and you said, "Okay, so if you're stuck that way, what science do you actually lose?" We push people to make compromises to make it affordable. And we did that across the board, whether it be engineering, mission design. We tried to make everything synergistic. Could we design an orbit where it worked with the exact design of the spacecraft and the way the instruments were going to observe.

Scott Bolton: And when you get into a flagship, a traditional flagship, you have individual principal investigators all building their instrument to be the best that they can possibly put in. And then you have the spacecraft team trying to make the best possible spacecraft that has the most robustness and reliability. And then you have mission design trying to do whatever they can do trick wise. And so, I remember when I was helping after Juno was started, I was kind of meeting at the early things that eventually led to ISA's JUICE mission.

Scott Bolton: And they were coming back with spacecraft designs and instrument designs. And I said, "If we could combine these, I think you could save money." And they said, "Well, the way our program works, we can't look at those things together. We need to send the spacecraft out to be designed separately. I mean, we're telling them it has to have some of these instruments on it, but we can't actually create it together like you did." And I think NASA has that same problem with flagships.

Casey Dreier: That sounds like there's just a structural advantage from a management perspective that competed missions, like New Frontiers has that you in this case, or the PI is kind of looking at the whole project, under this multivariate analysis of efficiency, not just it's one little lane of, as you were saying, mass efficiency, quality of instrumentation. Someone has a holistic responsibility and commitment to it.

Scott Bolton: That's right. That's really how it comes down. And even the science is that way, like when we were planning. I spent a lot of times working on planning, Cassini observations, even Galileo observations. Trying to deal with competing interests, and how do we fit this into the bag. And so, I looked at my experiences and my colleagues' experiences and said, "We want to avoid all that. What we want to have is really simple ops or we're not going to be able to fit in the box." And so we tried to say, "How can we design this so that the decisions were making on what to observe and how to observe them are minimal?" That most of it is just going to work, no matter what we do.

Scott Bolton: And so, we ended up with basically a mission design and a spacecraft design and the instruments placement, so that there were only two modes. One was pointing the high gain antenna at the Earth, which I needed to do if I was going to get the gravity science signal back while I flew by Jupiter. And the other was, I could move it, so that I can optimize the microwave mapping of the atmosphere, which was new.

Scott Bolton: And then we looked at it and said, "Everything else should just be able to ride along and not care." And so, we designed it that way. And anybody that said, "No, I care, I care," we said, "Well, you need to make a very strong science case for us, so listen. And consider this because we don't have the resources. And we want to fit this. And we think it's worth doing this." And everybody bought into it. And that's really important.

Casey Dreier: What kind of lessons can you take more broadly? I can see an argument back that you can have a mission like Juno or more targeted discovering new frontiers only if you've done this kind of generalized large flagship that's an exploratory mission. So, how much or to put it another way, how much do you depend on having a targeted set of science questions to define and help constrain your mission design to help get to this efficiency in designing cost versus pure exploratory first time? Could you do a Juno at Uranus or Neptune? Something that hasn't had an orbiter before?

Scott Bolton: Yeah, absolutely. In fact, I think that it would be a mistake to do a flagship to the Ice Giants, because Juno has already demonstrated that "I could do that. I could go there and explore that system. And I know enough about it." Right? I already know how the magnetic fields are oriented. I know how the bodies are rotating around, spinning. I know where the basic moons are. You don't need to do a flagship there. And in fact, Juno is able to now in its extended mission demonstrate that it can do close satellite flybys, magnetospheric science, right?

Scott Bolton: Look at the Aurora. Look at the deep atmosphere. Look at the internal structure with the gravity. That's what a flagship really was doing, was trying to do that system. We just demonstrated that. And in fact, Lori Glaze, when we were announced the extended mission, even commented "About how this thing is becoming a system wide explorer." We were even going to explore the rings, right? And that's something that was normally a flagship was needed for.

Scott Bolton: My thought about that, and I've made some of these arguments to the community, is that you could send two Junos for the price of a flagship. And so, if you were worried about having satellites and the body itself compromised too much, you could actually send two of them. But what I really believe is that you could send a Juno to, and it's not Juno, right? It will be called something else and it will be tuned a little bit and it will be more advanced, right? Because the generation has gone on in science. But you could send something to Uranus and another one to Neptune for the price of a single flagship and probably less.

Scott Bolton: If you look at what's going on with Clipper even, they're very similar to us. Very complicated orbits. They got to deal with radiation. They have a payload that's commensurate with ours. I mean, we have a lot of instruments, and they're pretty advanced. There's a little differences. Of course, they got radar and we have the microwave that's passive and things like that. They have mass spectrometers. We don't have that. But a lot of it is, those are not big, big differences. And yet, the costs are very different. And the risk factor, because it's got that cost, they're trying to minimize their risk even more than we did. We were willing to take some risks.

Scott Bolton: But I think if you could have done Clipper for a billion and a half, I mean, you could or $2 billion even, you could have done more of them. Maybe you could have gotten the Europa Lander and Clipper. So, I think we have to really ask ourselves is when are flagships needed? And I don't believe in my view, after experiencing Juno, that we should have flagships as a default just to go explore the Ice Giants or new bodies like that, just because with the argument being, "We need system-wide science."

Scott Bolton: I think there are implementations of something that might require flagship investments. So, if I want to go somewhere and bring back a sample from Enceladus or Europa or maybe even other things or go or Mars, you may have so many complexities in that, that you need the flagship. Just because it's so complex engineering-wise. But if you can re-outfit a Juno and decide, "Okay, maybe I want three axes stabilized. Maybe I don't want a spinner. Maybe I want a little more capable camera," right? Although our camera has done well, it's designed for outreach, not necessarily science, so you might change how it works a little bit or what that is. But those represent tens of millions of dollars difference, not billions.

Casey Dreier: And that goes to the fundamental challenge I see because when you get something like Clipper, which was pitched as the cheaper alternative to the Jupiter or the Europa Orbiter that was called out in the Decadal for being too expensive, it's just for inflation will be about as much as that Decadal estimate of $4.7 billion. That ultimately, even if you pull off the mission, which I'm grateful Clipper is happening, you just have fewer resources to do more missions to the outer planets. And then you get this trickle of once in a generation type of mega missions. And ultimately, that seems not great for the community of outer planet scientists, because you're putting so many resources into the single missions.

Casey Dreier: Like what you were just saying, two missions at once to an Ice Giant sounded so exciting to me, but it sounds like at the end of the day, there's an institutional tension, right? Where the NASA Centers want the big projects, because there's lots of money in that, that helps keep their standing armies going versus the scientific interest of having as much data as possible. But there's also a cross pressure in scientific data of like, "I want the best data possible" versus "the only data that I could get."

Casey Dreier: So, how do you try to balance that? How do you break out of this cycle that we seem to be stuck in with outer planets kind of defaulting to these big flagship missions be? I mean, Juno, you were kind of talking about Juno as this example, but clearly, it hasn't broken this paradigm yet.

Scott Bolton: Well, it hasn't yet, although there's hope that the extended mission demonstration of ring and satellite science is going to make people think that. I mean, the advantage to the to the New Frontiers approach is it's a lot faster, right? And so, that should be a big carrot to us. The other is that the argument that you need to keep what you call the armies, but it's really the technical capabilities of our institutions like JPL or APL or NASA Goddard. I mean, we don't want to lose that, right? I mean, that would be a big thing.

Scott Bolton: So, there is some minimal expenditure that NASA has to be able to do in order to keep the engineering and scientific capabilities that we've grown without shrinking them necessarily. But I think the argument could be made that if you had multiple PI class missions that were going out there, that you don't really need the flagship. In other words, if I had to spend the money that a flagship costs, but I spent it on two or three missions, I'm still employing the same number of people, because all the money is really labor, right?

Scott Bolton: But the scientists have to be educated or experienced enough to realize that they have to make compromises. That they have to sit in the room and be part of the team that's making this happen and recognize that if you go outside the box too far, you don't win because even if you can get the mission, you've delayed it by 10 years or more. And you've cost all these other opportunities. And so, scientists right up front have to say, "What's the real data that I absolutely need and not get too greedy?"

Scott Bolton: We really spent a lot of time on that on Juno and said, "Okay, we could fly more instruments." And we were arguing, "What should we put on the payload?" And we had to make some compromises and said, "This is enough." So, if we had an engine in NASA that was pumping out even more New Frontiers and Discovery missions, I think an argument could be made that way. And some of them could be very general, right? I mean, we could send a Discovery mission that was very focused to IO, but we can also send a New Frontiers mission that travels around like Juno does to different parts of a planetary system.

Scott Bolton: The scientists have to be able to make the compromises. NASA has to have the vision and the structure to say, "We want to make sure we have all the PI class missions," and the decadal has the support that. So, that the Decadal, previous ones have said, "Don't let Clipper go too far over budget at the expense of the Discovery or New Frontier programs." Yet that, in my view, probably still happens to some extent and you're sort of trapped. Once you're in that mode, and you've spent $2 or $3 billion, it's hard to say, "Slow down for this," right? You've already made the commitment.

Scott Bolton: So, I think we have to decide very carefully what is a flagship and what isn't? What's needed? And get something within the bounds. The scientists also have to buy into it. Scientists know that if you're on a flagship, if I do have a Clipper or a Cassini, I'm much more likely as a scientist to be able to become part of that team because Clipper and Cassini have science team numbers that are much, much higher than Juno's. PI class mission, you're allowed to put in, maybe do 30, 40 co-investigators. And part of it is because you can't spend a lot in Phase E. The flagships loosen those reins up quite a bit. But I think that you could find a compromise and a happy medium in that as well, where you employ more people.

Scott Bolton: As a science team, we've brought in people into Juno quite a bit, but we're still nowhere near the size of Clipper and I'm on Clipper, right? So, their science team is much larger, which makes it much harder to manage. And there's also an aspect of Clipper that's kind of interesting in that it's split or shared between JPL and APL. And while that's a healthy thing to do, and I actually advocated to do that back in Discovery, and for pre-Juno stuff, but you have to be careful that you're not feeding two institutions for really redundant work.

Scott Bolton: How many managers and science team leaders do you need in each of these? You just have to look at every possible way to make things efficient. And you need to find a way to continue to bridge things like JPL and APL and Goddard, so that they're working together, rather than completely competing. And you could do that I think inside of a New Frontiers mission. You could still do that.

Casey Dreier: Last question here. Again, we're recording this on the 50th anniversary of Pioneer 10, which really opens up our exploration of the outer planets for the first time in human history, 50 years ago. What are you looking forward to most from where we are at this point, 50 years on?

Scott Bolton: Looking ahead the next 50 years?

Casey Dreier: Yeah.

Scott Bolton: Well, I think we've mentioned a couple of them. The Ice Giants is something that I think is inevitable that we would have an orbiter there. And I'm not sure I think it's worth a simple flyby. I think for the price of a New Frontiers mission, you should be able to put something in orbit there and really investigate both the moons and the body. I hope that we send something like that to Uranus and a separate thing like that to Neptune in near the same timeframe, so that we have the advantages of being able to compare them, which I think is really beneficial.

Scott Bolton: I think following up on some of Cassini's spectacular discoveries. We have Dragonfly coming up for Titan, and I'm really a big fan of that mission and looking forward to its results. But I think following up with Enceladus is also really important. Maybe doing something with the rings of Saturn, which were so amazing. And maybe even a Juno like thing at Saturn could be argued for in the sense that we're seeing deep into the atmosphere and the question is, is Saturn's atmosphere like that? We have a little bit of an idea that but not enough. I was able to help advocate for the end of the Cassini mission to go into a polar orbit like Juno around Saturn. The motivation I had for those arguments was to be able to compare the two. So, we got some magnetic fields and gravity science to do that with and that was great. We could do more.

Scott Bolton: I also think, going back to Jupiter, getting something more around Europa, landing in there. Going and exploring Calisto. I think now is the time to in the next 50 years to start to look at these, the moon and satellites of these giant planets, because they are worlds unto themselves. Understanding the role of the small bodies, we go out and we look at comets and asteroids, individually, and it takes a lot to go there. And so, you kind of pick them almost randomly, and you say, "Let's go to this one. Let's go to that one."

Scott Bolton: And what we really need to do is develop a capability to look across many small bodies and understand which ones are interesting compositionally already, which ones have isotopes and organics and things like that, that make us want to learn that and get close up to it. And maybe we can figure out a way I think with some of the submillimeter wave and microwave observations that we could actually learn about the small bodies from afar. And then get better at figuring out which ones to go and encounter and sniff with a mass spectrometer or get a sample of. Because those are going to tell us how the solar system was formed and what bodies belonged to what other bodies.

Scott Bolton: So, in the next 50 years, I'm hoping all of that happens. And of course, that's just planetary. I believe things like James Webb and the great astrophysical telescopes are also really, really critical. And those are probably a place where you must have flagship investments. Forget James Webb's price, but I mean, anything that you want to build that's really big enough and capable out there, whether it be in the infrared, X-ray, all these submillimeter, all represents series investments. And as we discover extrasolar planetary systems, I think it becomes more and more important to go explore those and bridge what we're learning about our solar system, with what we're seeing an extrasolar systems.

Scott Bolton: So, the next 50 years, I hope to see more of a connection between those two fields. And we're trying to advocate that now with Juno's results. Because Jupiter represents a giant planet anywhere, right? And understanding its role and its importance and what it's made of and how it was built and structured and powered, formed and evolved is critical to us. That we're going to learn as we get more and more observations from even ground-based like Alma, of these extrasolar systems. So I think we're going to see that.

Scott Bolton: And then lastly is the idea that Juno has taught us that we have to start to study these bodies and planetary science, interdisciplinary. So, in the days of Voyager, Galileo, and Cassini, I was part of those science teams, and they were divided up into working groups that were Magnetospheric, or atmospheres or whatever you're looking at and satellites. And they scientists pretty much worked in isolation of the other ones, and they would report the results, and you'd listen in like a spectator on the other ones. And what we learned on Juno was we started to learn so much. We started to see the coupling between the atmosphere and the interior, and the magnetic field, and all of these things and so, you have to start.

Scott Bolton: At this point now, we are separated in working groups when I originally formed it, and we're abandoning that. We're keeping the groups but everybody wants to be in everybody else's meeting. Because what they're doing matters to their understanding. We now try to meet more and more in what's called Plenary Science discussions so that the interiors can hear what the atmosphere is learning. Because deep enough down in the atmosphere, the interior and atmosphere mix and depend on each other. And the discoveries of how they're working, are revealing these, these physical connections. And so, I think that's where planetary science is headed is that we're going to need to view these things in a much more interdisciplinary fashion as we learn more and more.

Casey Dreier: Lots to do, so lots of great opportunities looking forward. Dr. Scott Bolton, I want to thank you again for your time today and your insights on Juno and all the exciting discoveries ahead.

Scott Bolton: Thank you very much.

Mat Kaplan: Principal Investigator for the Juno mission, Scott Bolton, who's been heard on the weekly show many times and has brought this entire new avenue of conversation to the Space Policy Edition this month.

Mat Kaplan: Casey, great conversations, both of them, Scott and Mark Wolverton. Thank you very much for this. Of course, I look forward to talking to you again next month. But what else are you looking forward to between now and then?

Casey Dreier: Well, very relevant to this entire discussion, which we will see the science community attempt to potentially grapple with is very soon, maybe next month, maybe two months, we will see the Planetary Science Decadal Survey released for the this coming decade. So, that's a big important document we will talk a lot about.

Casey Dreier: And right now, probably as we're talking about it, the team who's writing that report is arguing about probably the cost of the various options for some sorts of outer planet missions, either to the Ice Giants or to Titan to Enceladus. Trying to understand the costs of those and how that could work into a projected future budget envelope for Planetary Science. So, the more expensive those are, the fewer they can do, the harder it is to prioritize. So, we will see what comes out of this next round of Decadal Survey reports very soon.

Mat Kaplan: All of that coming up in future episodes of the Space Policy Edition of Planetary Radio. Of course, I'll be with you every week with the regular edition of the show. Casey, best of luck to you next week with the Day of Action, this virtual day of action, and all those other terrific volunteers who are going to be joining you in the virtual halls of Capitol Hill. And I look forward to talking to you again soon.

Casey Dreier: Thanks, Matt. We'll talk next month.

Mat Kaplan: Casey Dreier, Chief Advocate for The Planetary Society is also our Senior Space Policy Adviser. We're very glad that you joined us and if you really want to join us is the place to go. Thanks for being part of this. Ad Astra.