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The Planetary Society Weblog
By Emily Lakdawalla
Notes from the Venus Express post-orbit-insertion press conference
Apr. 11, 2006 | 03:50 PDT | 10:50 UTC
It was a very happy group at the press conference, though some looked a little bit tired. Press conferences that happen after successful spacecraft maneuvers contain a lot of celebration and very little in the way of new information, but I typed as fast as I could to record what people said; here are my notes, as best as I could make them, though I warn that I couldn't always keep up with the speakers. There are a couple of very interesting bits of new information that I highlighted in bold below...
Jean-Jacques Dordain, Director General of ESA: "So we have been captured by Venus. It's a great day, and it's already today a great success. First of all it is a political success because it is 17 member states cooperating, providing continuous support to the science program. This is also a technological success. It's also a success of cooperation. Cooperation first within Europe, between the scientists, industry, ESA national alliances, operators. And this cooperation is not only successful but we have also demonstrated that we can also be quick. Also Venus Express was launched by a Russian launcher, and the capture has been supported by NASA with its station in Madrid. So now we have a basis for a scientific success. Because the scientific community have demonstrated that when they have a good spacecraft, they are able to push the frontier of knowledge. Beyond that scientific success, we will continue to better understand, better predict the Earth for the betterment of the world."
Manfred Warhaut, Venus Express Flight Operations Director: "What followed launch was a textbook story. We have successfully commissioned the spacecraft system. We went on what is called a quiescent cruise, though to be honest it was not quiet for us. A long quiet last night was very rewarding, because none of these contingencies [that were planned for] occurred. Telemetry indicates the spacecraft has very well sustained this maneuver."
Gaele Winters, ESA Director for Operations and Infrastructure: "Our job is to operate satellites and to maximize the return to the users on Earth. We have built up a lot of experience in planetary missions. Everything went as it was planned, cleanly, without difficulties. At ESOC, we know how many things can go wrong, but it didn't happen."
David Southwood, ESA Director of Science: "We aren't finished with the planets. Venus is one more planet checked off on the list. I believe we Europeans look at things differently, we come from a different culture. It is important for us to do our own planetary exploration. But we are still planning to go back to Mars and to go to Mercury. But I have to tell you, that the planets may seem far away, but there is a lot more out there… in the next few years, we will be shifting our emphasis, beyond our solar system, even beyond our galaxy. Our next major missions will be astronomy over the next few years. But it all comes back to a basic question that I'm sure just about everybody has asked: how did we turn up here? That's the kind of question we're tackling on the grand scale at ESA. It's essential that we go into space to do it. Venus is just one more step on that route."
Don McCoy, Venus Express Project Manager: "We've had a very successful day. I think that people have the impression that engineers are very boring sorts. And we are boring, because you saw today that we were excited about [everything being normal]." He gets in a dig at the scientists for some lateness with the delivery of the instruments, but closes with "To the scientists, I wish you great moments ahead, and I'll read about it." His is the first speech that wins applause, I think because this moment represents more or less the end of his major responsibility: to build a spacecraft and send it to Venus.
Håkan Svedhem, Venus Express Project Scientist: "I am a very happy man today. Now our work starts, and we do this now for a couple of years. We have many questions, even though Venus has been visited by many spacecraft in the past. Perhaps the noble goal of it all is to understand why Venus is like it is, why it is not more like the Earth. I hope you all will follow the mission and follow our data, and I am sure you will be very excited with the data we will produce."
Now it is handed over to the press for questions and answers. I didn't write down the questions, so I'll try my best to indicate what they were before each answer...
[Question about how much fuel remains on board]
McCoy: "In fact we have quite a bit margin of fuel on board. We allocate extra fuel for a bad launch, for maneuvers on route, [and everything was nominal] so we probably have enough fuel to do the extended mission, and quite frankly I think we could do another one after that. We have enough fuel for 4 and a half to 6 years."
[Was timing of events today as expected? and was orbit as expected]
Warhaut: "We got all the announcements at the expected time. There was one moment in time where we were supposed to come out of occultation, and we had a delay of two minutes, but we did not know they [the DSN] were sweeping the signal. The overall burn was exactly as planned. [With regard to the orbit,] I ask you to wait one hour. We have now switched on the ranging signal to enable us to determine the position, so we have to hang on another half an hour or hour or so."
[Why the choice of orbit with periapsis near north pole?]
Svedhem: "One reason is we have a very elliptical orbit and we want to have a very elliptical orbit where we are very close to one hemisphere to do detailed studies of features in atmosphere and on the surface. At the same time by having a high apocenter we can have a very good global view of southern hemisphere; at apocenter we can hang for several hours."
[What is the plan for end of mission?]
McCoy: "In fact the orbit will naturally decay into Venus' atmosphere. We certainly haven't got detailed plans yet. But it would be a perfect opportunity for Europe to gain experience in aerobraking for the future."
[How has duplication of Mars Express helped, and how are the two different?]
McCoy: "We had quite an exciting start for Mars Express, which is not good news for engineers; we went into safe mode after starting. This is an example of how we have learned to adapt the lessons of Mars Express to Venus. We have learned how to tailor our safe modes to more realistic conditions. Also on Mars Express there was some question with the star tracker. We took all of these lessons to Venus Express, and we don't have these problems on Venus Express. Finally, Mars Express could operate very well in orbit; as you saw Venus Express went into orbit completely nominally. The only major difference is the communications, where we have an extra antenna, and also the thermal environment, which is hotter."
[Will this kind of twin spacecraft be done again?]
Southwood: "Venus Express has a resemblance to Mars Express, and it cost us considerably less than it would have done had we started from scratch. You get some efficiencies of scale. I would imagine we saved on the order of 100 million Euros in just running Venus Express in the slipstream of Mars Express, which in turn was run in the slipstream of Rosetta. Well, I would like it to set a precedent, but we don't have a big enough budget to go on doing missions of a similar nature. We have to go on exploring the universe, and you can't do that with missions like Venus Express and Mars Express. But we try with the next two missions that we do, Herschel and Planck. They are being built as brother and sister; there are enormous differences between the two, but there are also commonalities, so we get more bang for our Euro. That doesn't sound quite as good in European as it does in American."
[What is the timeline for the coming days?]
Warhaut: "We will this afternoon switch on all the subsystems. We will plan for windows of science opportunity already in this first 9-day orbit, which we offer on a best-effort basis, if the orbit now permits this. If it permits, we have 6 windows available to the payload, which they will be able to make observations of Venus from a large distance. We wish to reach the nominal orbit on 7 May, then there is a period of 4 weeks set aside to make sure instruments are playing well together."
[Will ESA be returning to planetary exploration?]
Southwood: "I can predict right away that my successor may be sitting in this room 7, 8, 9 years from now, because we will be landing on comet Churyumov-Gerasimenko, we'll be orbiting Mercury, we'll have ExoMars in the same time scale. Don't worry, we'll be back in the planets."
[Will ESA be cooperating with NASA to go to Europa?]
Southwood: "With regard to international cooperation, we try to mix elements. We go to Mercury with the Japanese; that's a first to us, and it's a very important first. I think we will be going back into space with the Americans. I sure hope we are going to see the JWST launch, and that will be a joint European and NASA experiment. As for the big planets, the giant planets are almost like solar systems of their own. A big question though, is whether it's Europa, a more complex mission, looking at the entire Jupiter system, or whether you go back to this extraordinary body discovered recently, Enceladus, with liquid water where it has no right to be. Of course now, scientists are explaining why it is so; but that is one of the joys of scientific exploration, you learn how creative scientists are."
[If fuel is not a limiter to lifetime of spacecraft, is there something more likely to limit it?]
McCoy: "Fuel is not the only issue. For a mission like this, you size the solar arrays for leaving earth, so there is a fair amount of margin. Batteries are probably not an issue. Probably what does happen is that the thermal protection degrades with time. The satellite can get quite warm. We may have to shut down some instruments, tailor operations depending on the heat situation."
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