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NASA is visiting 8 asteroids in 8 years. Here are 8 things to know about the missions

Posted by Jason Davis

04-01-2017 16:33 CST

Topics: Lucy mission, Psyche mission, mission status

Today, NASA announced two new planetary science missions that, in total, will visit eight asteroids between 2025 and 2033. It will be a long wait, but that will eventually be eight new worlds in roughly eight years!

The spacecraft, named Lucy and Psyche, launch in 2021 and 2023. NASA says they will fill important gaps in our understanding of how the solar system was formed—when our sun was a mere 10 million years old.

Here are eight things to know about the missions.



Lucy, a mission to fly by multiple Trojan asteroids near Jupiter, was formally greenlit by NASA in January 2017.

1. Lucy will fly by multiple asteroids near Jupiter.

Lucy will visit one main belt asteroid and six Trojan asteroids. Trojans roughly share the same orbit as Jupiter and are held in place by the giant planet's gravity. Scientists aren't exactly sure where they came from—they could even be captured comets or Kuiper Belt objects. 

The spacecraft launches in 2021. In 2025, it will whizz past a main belt asteroid between Mars and Jupiter, and arrive at its first Trojan target in 2027. Lucy will then proceed to visit five other Trojans, wrapping up its tour in 2033.

On a press call today, Lucy principal investigator Hal Levison explained that the probe is named after a famous 3.2 million year-old fossil of a human ancestor.

"These (Trojan asteroids) really are really the fossils of planet formation," he said.


SSL / Peter Rubin

Psyche will visit a metallic asteroid of the same name. The mission was approved by NASA in January 2017.

2. Psyche is heading to a wicked-cool metal world.

In the main asteroid belt resides a one-of-a-kind (at least, so far as we've discovered) metal world named Psyche. It is composed of metallic iron and nickel, like Earth's core, and might have splatters of solid metal jutting off its surface.

Is Psyche the exposed inner core of what used to be a much larger planet that was battered by drive-by asteroid collisions? That's what Lindy Elkins-Tanton, the mission's principal investigator at Arizona State University in Tempe, hopes to find out. 

"Out of our initial excitement, we just named our mission directly after what we're going to visit—Psyche," she said.

Psyche launches in 2023 and arrives in 2030. Unlike Lucy, it will slow down and enter orbit.

3. Lucy and Psyche are NASA's first competitively selected planetary missions in more than four years.

The last time NASA greenlit a competitvely selected planetary science probe was 2012.

In August of that year, the agency announced the selection of Insight, a Mars geophysical monitoring station originally slated to launch in 2016. Due to a leaky vacuum seal in its main science instrument, Insight's launch was pushed to 2018

If you're wondering what a competitively selected mission is, scroll ahead to number five.

4. As a refresher, here's a little background about planetary science mission types.

There are three classes of planetary science missions: Discovery, New Frontiers and flagship missions.

Lucy and Psyche are Discovery missions. These are the least expensive items on NASA's mission menu, and are cost-capped at less than $500 million, not including launch and operations costs. Twelve Discovery missions have flown thus far, starting with the Near-Earth Asteroid Rendezvous (NEAR) probe in 1996. 

New Frontiers missions are mid-tier, and have included New Horizons, Juno and OSIRIS-REx. The latter, now on its way to visit asteroid Bennu, has a price tag of about $800 million, including the cost of its Atlas V carrier rocket.

Finally, there are flagship missions—big, agency programs that take a lot of resources. The Curiosity and Mars 2020 rovers are flagships, as is the proposed Europa mission. 

5. Lucy and Psyche were competitively selected—meaning some scientists got left out.

Lucy and Psyche were selected from an initial field of 27 Discovery mission contenders that was whittled down to five last year.

As Casey Dreier and Emily Lakdwalla wrote at the time, the Discovery program was originally supposed to offer flight opportunities every two years, but ongoing budget cuts to the agency's planetary science division have slowed that cadence.

The triumph of Lucy and Psyche, unfortunately, means three other missions were left on the table. One, the NEOCam asteroid hunting telescope, will continue to receive study funding for another year because it could be used to fulfill other NASA asteroid objectives.

The other two proposed missions would have headed to Venus, where an American probe has not been since Magellan entered orbit in 1990.

6. Lucy and Psyche are scientist-led missions.

Unlike flagship missions such as Curiosity, Discovery missions are managed more directly by their proposing teams.

Lucy PI Hal Levison is a scientist at the Southwest Research Institute in Boulder, Colorado. SwRI will lead the overall science investigation. NASA's Goddard Space Flight Center is providing mission management, systems engineering, and safety and mission assurance, and the spacecraft will be built by Lockheed Martin.

Psyche's science team is located at Arizona State University; as is PI Lindy Elkins-Tanton. NASA's Jet Propulsion Laboratory in Pasadena, California manages the Psyche mission. The spacecraft structure will be built by Space Systems / Loral.

7. Both spacecraft make use of heritage technologies.

When practical, NASA likes to use flight-proven hardware—often referred to as heritage technology. There are multiple benefits; it's usually cheaper if you don't have to develop new components from scratch, and it's always good to know that something has already flown in space successfully.

Lucy uses enhanced versions of science instruments that flew on the New Horizons and OSIRIS-REx missions, and some of Lucy's team members also come from those programs.

The Psyche spacecraft itself is very Dawn-like in appearance, and uses solar-electric propulsion—a technology vetted thoroughly during Dawn's ten-year mission.

8. The new missions have a Planetary Society connection.

I'd be remiss not to mention a Planetary Society connection to both missions: Our president, Jim Bell, is the deputy principal investigator for Psyche, and a co-investigator on Lucy.

Congratulations, Jim!

Psyche: Journey to a Metal World from School of Earth & Space on Vimeo.

See other posts from January 2017


Or read more blog entries about: Lucy mission, Psyche mission, mission status


VirgilSamms: 01/04/2017 07:11 CST

Being more than a little worried about an asteroid or comet impact I was hoping they would pick the NEO mission but oh well. I notice several forums that NewSpace fans post on is venting their standard NASA/state-hate and complaining that Venus was not selected. I don't think it would matter what was selected- anything NASA does (except supporting SpaceX of course) is wrong in their view. The Ayn-Rand-in-Space-libertarians that make up a large segment of that cult despise the government and all government agencies and concerning space exploration want to "hand it over to Musk." Their John Galt/Tony Stark hero worship is bizarre but has had a completely unrealized and damaging effect on public opinion over the last half a decade. Sad and ruinous for space exploration.

Atom: 01/04/2017 10:32 CST

I love both of these missions and highly anticipate their implementation. I was disappointed Venus was again byassed but if NASA partners with Russia on the Venera D proposal and if ESA selects EnVision then the same science objectives will be met. Both of these missions will be more capable than their Discovery counterparts, Veritas and Davinci. Both will will likely be ready by the second half of the 2020's. The selection of Psyche also clears one of the New Frontiers proposals (Trojan tour) from consideration for all future competitions and selections. This is good news for all the remaining proposals in an already crowded list.

Arbitrary: 01/05/2017 04:29 CST

@VirgilSamms Well, NASA has proven that they don't know how to build launchers. The shuttle was an idiotic design, even the Soviets knew how to do it right. And SLS+Orion is about as expensive as all launchers and spacecrafts developed in the whole world during the last 40 years, although it consists of old existing legacy components and ground systems. It also achieves nothing new, it will be a 55 year old system already on its first launch. It is important to recognize such total failures and realize that NASA must not try to develop launchers and crewed spacecrafts anymore. NASA today is associated with corruption more than with space because of the huge SLS+Orion fraud and fail at the expense of space exploration.

Arbitrary: 01/05/2017 04:39 CST

Doesn't the proposed Venus orbiter and lander mission look good for a New Frontier decision in 2019 now? @Atom International cooperation means almost certain failure for political reasons. Everything becomes several times more expensive because there are multiple sets of special interests that loot the budget and things take much longer since different bureaucracies can't talk with each other. See how the US canceled participation with ESA in ExoMars and the Europa moon missions, and how ESA now delays the service module for the Orion and on and on. ESA has never developed a crewed spacecraft. They find that the specifications are such that they must use components and tools only made in the US (that's the whole purpose from the beginning), so they get angry that they cannot loot that money for their own local special interests. And suddenly something unexpected and irrelevant like the occupation of a peninsula happens and everything is canceled. I'm sorry, but an international Venus mission means no Venus mission.

Karen: 01/05/2017 08:48 CST

@Arbitrary - Yeah, about that... have they actually defined which, exactly, mission(s) plan to compete? VEXAG is not at all candid about what sort of goals they want to achieve, but I've not seen much converging on specifics. I know there's VME (bellows balloon - multiple surface takeoff/landing, low-level atmospheric and surface sampling), VITaL (tessera lander), and VCM (traditional balloon, 21 days in the middle cloud layer, plus miniprobe & dropsondes). Are there others? I have to say, while all are quite interesting to me, I'd personally go with VCM. You get lower atmospheric data as well via the miniprobe/sondes (and can drop them wherever your data suggests would be most useful, including transient phenomina - storms, suspected volcanic activity, etc), but also provide the long-term presence in the middle cloud needed to help us match up satellite observations with local weather conditions and hopefully finally answer what, if any, precipitation and lightning there is and in what cloud layers. I just think it's a shame that they didn't do any study on the alternative architecture with solar arrays; it could have potentially allowed much longer time in the atmosphere (even if the design life was only 21 days), while the last version I read *will* die when the primary cells run out. Also, I'd like to see the TRL pushed up for the use of solar arrays on Venus balloons. If they don't go with it, then hopefully they'd go with VITaL. Bellows balloons are a neat concept that could prove very useful in future missions, and the surface of Venus is a crazy bizarre place. VITaL's bellows is only a sort of half-implemented system (can expand, but not contract), but it'd lay the groundwork for full bellows balloons in the future - which are a potential enabling tech for sample return. And for any future colonization efforts, they represent a means to bring surface material back up to habitable altitudes.

Karen: 01/05/2017 08:51 CST

I haven't seen anything about *where*, exactly, VITaL plans to land. Hopefully in the highlands. Knowing whether they're (as some have theorized) old granitic remnants of ancient continents would be huge for our understanding of the planet. And I so want to know what the high altitude radar-reflective surface frosts/snows are made out of.

Atom: 01/05/2017 12:00 CST

@Arbitrary I agree with your assignment on international cooperation but with the total lack of dedicated Venus missions (minus the occasional gravity assist flyby) that is all we are left with. @Karen during the last New Frontiers competition the "Sage" proposal was a finalist. I would expect it to be resubmitted during the current round (NF4). It is a titanium pressure vessel similar to the Soviet Venera landers. The bellow balloons are a plutonium powered Flagship class "idea" which wasn't even considered during the last Decadal.

Karen: 01/05/2017 02:08 CST

@Atom: Hmm, I had previously read that VME was targeted at New Frontiers. Checking some more recent papers on it, it looks like that was their objective but they couldn't get it within the budget constraints. A shame. Indeed, how did I forget SAGE? Pretty run of the mill, uninspiring lander.... but we know so little about Venus, and instruments have advanced so much since Venera / Vega, we'd get a data trove regardless. Would be interesting to land on such young terrain, too.

Karen: 01/05/2017 02:10 CST

Ed: just noticed above that I wrote VITaL when I was referring to VME, two posts back. :Þ

Jason Davis: 01/05/2017 02:42 CST

Hi folks, We recently amended our commenting policy -- please give it a quick read. Just to stress two particular points: - Please don't discuss users' personal identities. - Please keep the discussion civil and on-topic. Off-topic rants poison the well and set a bad tone for anyone else wanting to join the discussion. Thanks, Jason

David Frankis: 01/06/2017 12:07 CST

I'm intrigued by the Psyche selection, since I didn't think it's really established that it's a metal world. Either the Psyche team (and the NASA bid assessors) think the evidence is strong enough, or they have a good Plan B for science at an M asteroid that isn't metal.

Arbitrary: 01/07/2017 07:11 CST

@David Frankis If its density is 5-7 kg/m^3 which several estimates seem to indicate, although with big error bars, then it would be even more interesting if it is not dominated by solid Ni-Fe. Unless you know of other ideas. It could be covered by regolith and look like any ordinary asteroid, not the cratered metal surface that artists imagine. But isn't it reasonable to pick out the potential odd balls for exploration first?

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