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Planetary News: Venus (2006)Reports from the May 1-2, 2006 Meeting of the Venus Exploration Analysis Group (VEXAG)Special Coverage from The Planetary Society WeblogMay 1-2, 2006The Planetary Society Weblog is written by the Society's Science and Technology Coordinator, Emily Lakdawalla. She attended a two-day meeting in Pasadena in May 2006 of the Venus Exploration Analysis Group, a body established by NASA to identify scientific priorities and strategy for exploration of Venus. VEXAG meeting: IntroductionMay. 1, 2006 | 19:47 PDT | May. 2 02:47 UTC
I spent today with about a hundred other people at the Westin hotel in Pasadena attending the second meeting of VEXAG. To recap, VEXAG is the Venus Exploration Analysis Group; their website says "The Venus Exploration Analysis Group (VEXAG) was established by NASA in July 2005 to identify scientific priorities and strategy for exploration of Venus.…VEXAG will report its findings and provide input to NASA, but will not make recommendations." That "will not make recommendations" part basically means that the "input" that VEXAG makes to NASA's planning has no teeth; NASA is in no way required to follow their input. NASA merely considers the input of the scientific community in its plans. (At least, that's the theory.) I took about 15 pages of notes today, so I'll probably write things down here in sections. As with all of my meeting recaps, I want to emphasize that when I report what people say, it's from notes being taken on a laptop as they were speaking, and my quotes aren't verbatim (though I try to get as much down as possible). I apologize to anyone in advance if I quote them incorrectly. This meeting is interesting because we are sort of at an ebb in NASA's exploration of Venus. It has been a very long time since NASA's last Venus mission, Magellan, ended its productive life, and there's no NASA Venus mission in the works. The Venus community is not particularly upset about that, although there have been people proposing to the Discovery program at every opportunity -- without success -- who certainly wish that their proposed spacecraft were being built. But it seems that there's a growing feeling that it's time for NASA to get back to Venus, and it is interesting to witnessing the first steps in the organization of what will eventually produce a future suite of Venus missions for NASA. (Or at least the scientific rationale for those missions.) At the same time, because there's no current NASA mission, this meeting is also just a lot of talk, some of it pretty bureaucratic. Bear with me; I'll try to explain why some of this is exciting if it begins to get dry. If you get bored with this entry, I'm getting to more interesting stuff in the next couple of entries. So what is the purpose of VEXAG? Steve Mackwell, one of the leaders of VEXAG, addressed that question during one of his presentations today. He said, "I don't think that even NASA knows where the advisory groups fit into the advisory structure. The analysis groups are designed to provide advice to the NASA Advisory Council subcommittees and also provide advice to the people at NASA, such as Adriana [Ocampo, of NASA's Science Mission Directorate], with whom we can connect to directly. These groups have a very important role to play, particularly in the currently top-down NASA advisory structure. If we are going to get input from the community into that structure, then these groups are very important for that. What we are doing today is that we are building a living document that looks at the objectives: what are the things that we should be chasing with respect to Venus science." Mackwell explained that the document of goals and objectives for Venus exploration must tie in to something called the "Solar System Exploration Strategic Roadmap." I find a copy of this document at the VEXAG website here (PDF format). The most relevant parts of the Roadmap -- which I've seen quoted both in VEXAG and in outer planets planning meetings -- are the following couple of paragraphs, which appear to be informing how these planning groups go about offering their words of advice to NASA: The United States has committed itself to the continued exploration of the solar system through the President's "Moon, Mars and Beyond" initiative. As a result of this initiative, it is an agency goal toIf you read that carefully, you'll notice how importantly "life" features into that list. Venus and life have not really ever been considered synonymous, but scientists are pretty creative; they're making plans for how VEXAG's goals will fit into this context. Mackwell threw three overarching goals onto the screen for Venus exploration, part of a document titled the "VEXAG Goals, Objectives, Investigations, and Priorities Document":"Conduct robotic exploration across the solar system for scientific purposes and to support human exploration. In particular, explore the moons of Jupiter, asteroids, and other bodies to search for evidence of life, to understand the history of the solar system, and to search for resources."But how do we construct an economically rational and technologically achievable ordering of planetary targets and exploration? The approach suggested in this roadmap begins with a set of five "scientific objectives": VEXAG Goals Mackwell went on to describe a bunch of more detailed scientific objectives, but those had already been covered in another presentation that I'll describe shortly. "Why are we here?" he closed. "The most important thing we can achieve is to develop a white paper in support of the science objectives of proposed missions. We're at a point where we've basically defined some goals. What we need to do now is to ratify those goals with your help," and to use them to build lists of scientific objectives, "and then say, are these the right ones? The objectives are things like: Is Venus active? What is the greenhouse? Why the super-rotating atmosphere? Then we define a series of measurements. The measurements are a way of going about answering the questions posed by the objectives. The plan is we'll take the results of these discussions, and then we'll assimilate them, which is always fun, and then get it up on the website as soon as we can. And we'll decide as we go along if we need to get groups of people together to hammer out details as we go." Like I said, it's a lot of talk. But in the absence of any current NASA Venus exploration program, it's important talk. Without community consensus on why we should study Venus, NASA's never going to invest in the technology development and missions to go there. OK, so that's the introduction. Now on to the substance of the meeting. VEXAG meeting: Open questions in Venus explorationMay. 1, 2006 | 20:10 PDT | May. 2 03:10 UTC
After the VEXAG meeting's introductory remarks, the first speaker was Larry Esposito, who gave an overview of what had happened at a recent special conference on Venus organized by the American Geophysical Union, the Chapman Conference. You can see some of the presentations from this conference on the VEXAG website, and Larry said that the proceedings were going to be published in an upcoming issue of the Journal of Geophysical Research. Larry said, "Objectives of the conference were to provide an overview of current missions and research directions, particularly to highlight open questions. This serves as an update to the NRC decadal survey for providing input to future exploration." There's a lot that still isn't known about Venus, as Larry summarized. "The deepest part of the atmosphere is still unexplored. It's hard to see. The basic fact of the rotation of the atmosphere is unexplained. We don't know the mineralogy of the surface. There's some indication that some regions of the surface including Beta-Atla-Themis are younger than others. There could have been an early magnetic field. The climate history of Venus has some sensitivities; one of the possibilities is that if it ever had an ocean it might have persisted for billions of years. Venus may have been habitable for much of its history!" See that word, "habitable?" If you go back to my previous blog entry you'll see how important the question of "habitability" is to NASA's strategic roadmap. You're going to see that word several more times. Larry summarized the open questions in Venus research that came out of the Chapman conference, dividing them into different scientific disciplines: Geology: With regard to the possibility of Venus maybe having an ocean for billions of years, Larry pointed out that previously published climate models have taken it for granted that Venus lost its oceans early in its history -- the models were aimed to produce that result. "But maybe that didn't happen," he said. Finally, this note of warning about the future of our own planet: In about a billion years, Earth may experience a runaway greenhouse. There are regions on Earth where the climate is locally in this situation." So, what does all of this discussion that came out of the Chapman conference mean for long-range planning? Larry said, "We looked at the results and asked ourselves: is there an update to the decadal survey? I'm happy to report at least the conference organizers are not looking at any major changes in recommendations. Current missions will answer some questions and sharpen some others. Even after Venus Express and [JAXA's] Venus Climate Orbiter, key questions will remain unanswered, particularly concerning the history of the surface. Future measurements include seismology, heat flow, surface magnetic field, and altimetry. Future investigations will require technology development." VEXAG meeting: Venus Express statusMay. 1, 2006 | 20:45 PDT | May. 2 03:45 UTC
Next up after Larry Esposito was Adriana Ocampo, from NASA's Science Mission Directorate. (I should also note here that Adriana is on our Advisory Council). I don't have time tonight to summarize her talk but I want to quote here the shout-out she gave to ESA. "I wanted to start by asking Hâkan to stand up, to give congratulations for a successful VOI!!!!!!!!!" (The number of exclamation points there is a direct quote from her PowerPoint presentation.) There was much applause in the room; NASA may not be at Venus, but ESA sure is! I'm going to skip directly to what Hâkan Svedhem had to say about Venus Express (and then I'm quitting for the night). When he stood up to talk, there was applause again from the room. "Venus Express is really doing fine and I am very happy that is the case. We have come to the point now where things really look good." He began by giving an overview of the instruments, which I'll skip since there's a page on this site on Venus Express' instruments. He showed the shape of the science orbit, and here's a detail I hadn't noticed before. The orbit is a 24-hour orbit because that simplifies the planning of when Venus Express returns its data. All data from two hours before to two hours after Venus Express' closest approach is returned through ESA's dish in New Norcia. All the rest is returned through their other dish, at Cerberos. "It is all about lowering costs with ESA," Hâkan smiled. "The capture orbit period was 3.5 hours longer than expected; this was a very good result. This enables all the science that was designed for the capture orbit. We had 6 slots in that orbit" for science observations, Hâkan reported, and all of them were accomplished. Furthermore, "the spacecraft has demonstrated a very strong robsustnness and is working well. There have been no safe modes at all so for (versus 20-plus for Mars Express)." Recall that Venus Express' design is based upon Mars Express. "We had problematic substytems on Mars Express, but these all operate well [on Venus Express]. The thermal design is performing just as it should; no problems." He went on to an overview of the instrument status. "VMC operates okay, though there were some problems with flat field and calibration. These have now been improved. VIRTIS works very well in both modes. SPICAV works well in nadir mode; stellar and solar occultation modes and SOIR channel are still to be checked out. MAG is continuously operating, only solar wind so far." He explained that the magnetometer has two sensors, one internal to the spacecraft to detect the contribution of the fields from the spacecraft, and one on a one-meter boom; but the data from the one on the boom looks great even without the correction from the internal measurements. "ASPERA works well, but the data is not yet fully analyzed. And VeRA: the Ultrastable Oscillator is okay, but is still to be characterized after Venus Orbit Insertion for stability, drift, and noise." There's only one instrument left, and it's the only one delivering bad news to Venus Express. "Then we have a little problem here with PFS," Hâkan explained. "In the launch configuration it has a mirror which is the one that directs the beam to the planet or to cold space or to internal blackbody source for calibration. The launch configuration is the black body pointing. After launch, the launch configuration checked out fine; less susceptible to noise from the spacecraft; everyone is happy. But when we tired to change to something other than black body, we got less happy." The mirror was frozen in its launch configuration. Since Venus Orbit Insertion, the situation has changed a tiny bit for the better, but it's definitely not fixed. "We have been checking up a little bit, because indications show it has moved a bit but not completely. It is not looking any more at the black body; it is at a position between the outside and the blackbody. There is still hope." So, finally, Hâkan got to the data. He began with the two images that have already been published. "First VMC image was not too impressive; at this time we had not improved flat field. We were happy to get something down." He also showed the VIRTIS picture that they released earlier. So then he showed some new data, not yet released, and I wish I could reproduce it here. It is GORGEOUS. There are beautiful feathery details in the clouds, and all kinds of subtle color variations. He showed shots from all six science observations, and highlighted the "polar dipole," an oblong feature that you can see in the clouds, rotating from one image to the next. It's sort of an oval shape, about twice as long as it is wide. It looks kind of like it has 2 lobes." (I asked Kevin Baines later if these images were coming out in public release, and he said they probably wouldn't for a while; he said that they're really looking forward to the COSPAR meeting in Beijing in July, and that there will likely be a lot of public releases happening then.) Finally, Hâkan showed a movie from the Venus Monitoring Camera from the pericenter approach. VMC has a circular field of view, so the movie is kind of like looking out a porthole as the spacecraft swings by; Venus' clouds totally fill the field of view. You see bands of dark and light clouds wandering by; there are very feathery boundaries between the bands -- like there is a horizontal striping, but someone has taken a feather and drawn it across at an angle of 30 degrees to the bands, feathering their edges. I asked Larry Esposito about this later and he said that they were really not sure what caused the feathering, that it likely had something to do with compositional variations among the clouds, and that they were very excited about trying to figure it out. So that's it for tonight -- I'll have to put off writing about the rest of the meeting until tomorrow. VEXAG meeting: Presentation from NASA HQMay. 2, 2006 | 16:18 PDT | 23:18 UTC
I've had a busy second day of meetings and am only now getting back to the rest of my notes from yesterday's VEXAG meeting. Before I dive in to the political stuff, I should define a couple of terms that will show up below. For planning future missions, NASA has three basic mission sizes. Discovery is the smallest, around $350 million, and (in theory) there are supposed to be about 6 or 7 of those every decade. Next is New Frontiers, at around twice the cost of Discovery; in theory there are supposed to be 4 per decade. Finally there are flagship missions, at over a billion bucks, which are supposed to happen about once or at most twice per decade. We already know that NASA will not be maintaining that rate, but I think that most people would like to see that proportion remain constant. As I mentioned yesterday, Adriana Ocampo was on hand to give a presentation on behalf of NASA Headquarters. Of course, the situation with NASA's budget is very hairy right now, and a lot of people are upset about decisions that have been made about funding, but all in all the scientists in the room treated Adriana very gently. That's because unlike, for example, Mary Cleave, Adriana is a planetary scientist; she's known and respected within the community. She's also on The Planetary Society's advisory council. Adriana began with congratulations to Venus Express, and she also reported on the status of NASA funding for American scientists to work on Venus Express: "NASA is happy to be part of Venus Express via participating scientist and interdisciplinary scientist and support investigators, soon to be announced," she said. I talked with Hâkan Svedhem later and he said that the participating scientists were going to be announced in mid-May. These are people who have not been on the mission from the start, who are funded to join the mission team later. How they "rank" relative to the scientists who have been with the mission from the start depends upon the mission. I remember that on Mars Exploration Rover, Steve Squyres made a point of welcoming the participating scientists as members of the science team on an equal footing with the scientists who had worked so hard to make the mission happen; but on other missions, participating scientists are not regarded as equal. I'm not sure what the case will be with Venus Express. "Venus Express, with its timely results, will help define the next steps for Venus exploration," Adriana continued. "VEXAG plays a key role within the scientific community to bring about these next steps. It's encouraging for VEXAG to be working together with Venus Express, including the latest findings, to define the scientific priorities" for future missions. "That's a key aspect," she emphasized. "Prioritizing. Provide priorities for those science objectives. "NASA would encourage VEXAG to get together and coordinate with the other assessment groups -- OPAG, MEPAG, the lunar community -- to really try to have an integrated program. This would really help NASA HQ, to coordinate production of their white papers. We hope to see this coordination activity take place. "The NASA near term paths for Venus exploration are through Discovery and New Frontiers. That's the message from HQ at the moment. As you all know, there is a lot of activity taking place. This week is a key week. We have the NASA Advisory Council subcommittees meeting. A lot of persons that are here are playing a key role. Talk to Ellen Stofan to provide your ideas." David Grinspoon asked: "You mentioned it would be good to coordinate with MEPAG and OPAG. Is there any official forum for that conversation? How do you see it taking place?" Adriana: "It was suggested to have a dialogue on the executive committee level; it's left up to you as a community to decide. Maybe at DPS or in some meeting like that." Ellen Stofan asked: "Access to the lower atmosphere and surface of Venus requires technology investment. What are the plans right now for investments in extreme environment technologies?" Adriana: "With the budgetary challenges we have right now…Andy Dantzler [her boss] definitely recognizes the importance of this. He is trying to safeguard the line and trying to produce some guidelines so that we will be maintaining the strategic plan; that is partly why he is not here today. We'll have until the middle of May" to work on guidelines. Janet Luhmann pointed out that as originally envisioned, New Frontiers had four proposed mission concepts: a Pluto/Kuiper belt flyby, a Jupiter orbiter, a lunar south pole sample return, and a Venus in situ explorer. One of those missions has now been launched -- New Horizons -- and one has been selected -- Juno, the Jupiter orbiter. "For future New Frontiers opportunities, will there be competition between lunar south pole sample return and Venus in situ? Are those the only two that will be up for competition, or will others be introduced?" Adriana: "Certainly out of the decadal survey those were the four lines that were identified; two have already been fulfilled. The remaining two will come out to be high priority but they will have to be reassessed in the present environment as other priorities come out through other analysis groups [like OPAG and MEPAG]. That's why we suggest that the communities coordinate the groups for the executive level dialogue." Janet: "Things have really changed with the Vision for Space Exploration. Lunar things have moved into NASA's Exploration subdivision. Things have changed…" Adriana: "Things are very fluid at the moment. Lunar has moved to another office and things have been reassessed. Those are being defined as we speak; we probably have to wait a few months to have an understanding of that. Most likely the two areas defined by decadal survey [for future New Frontiers missions] will still remain important." Sushil Atreya: "A great deal of what we are discussing in this group also leads to flagship missions. Should we also be thinking of ambitious missions?" Adriana: "Discovery and New Frontiers are the near-term vehicles for Venus Exploration. Certainly to do a lot of the science objectives" defined by VEXAG for the future exploration of Venus "will require flagship missions. Right now that is really challenging because of the budget; we will have to wait. But for VEXAG to omit" plans for future flagship-sized missions "would be a mistake." Ralph McNutt: "How will Andy Dantzler set priorities?" This is a loaded question in the context of NASA's 2007 budget. NASA has already set priorities, and scientists do not like those priorities. Adriana: "That's a difficult question." (She laughed uncomfortably.) "The NASA budget drives the process. Many times, scientific guidelines that have been defined [by scientists] suffer deeply because the [congressional] earmarks are the ones who are really driving the budget. That's a constant challenge that all the directors have to face in the science mission directorate. It's not a clear path, it's not well defined. The inputs from scientists and the advisory council and its subcommittees -- this process has been put in place to facilitate the voices from the community and permit a forum for the community to produce some inputs to NASA. So when those come and then the earmarks come and all the things get merged, decisions are not always the optimum scientifically. So there isn't a clear answer I can tell you, 'he is making decisions one-two-three,' because it doesn't happen like that." McNutt: "Earmarks are an important subject to be aware of. All of us realize these are not good; they tend to short-circuit plans that the science community has made. The reason these keep coming up is that people get a little impatient with what they see going on at HQ. We do decadal survey and we make plans and then technology plans fall apart. I think one of the messages that needs to get carried back to Andy, and he's probably already aware of it, is this: a lot of the earmark threats arise because there is a frustration out of the community that it seems like we get a plan going in one direction and it gets torqued around because of budgetary issues. We all understand that. Whenever we hear that 'the science community's got to back off from earmarks,' it's understandable, but you guys need to understand what's driving some of this." Adriana: "It's a good point. I think they do, it's very well understood in the Science Mission Directorate. Earmarks come sometimes without good scientific rationale. I think it's important to coordinate not only with HQ but also with your congressional representatives." That is, don't just talk to your congresspeople to save a single mission; talk to them about the whole program being proposed by scientists for the future of exploration. VEXAG Meeting: Present and future Venus mission plansMay. 2, 2006 | 18:33 PDT | May. 3 01:33 UTC
Following Håkan Svedhem's presentation on the current status of Venus Express, there were several more presentations having to do with present and future missions. Håkan switched gears to talk about a recent European workshop on entry probes to Venus that was held at ESTEC in January. "It was realized quite early that Venus Express would not solve all the questions about Venus; even after [JAXA's mission] Planet-C we still need further studies. We need in-situ measurements," which means that someone needs to build a probe that will descend into Venus' atmosphere, much as Huygens did at Titan. Håkan continued, "The framework for this is ESA's Cosmic Vision Programme, which for some reason doesn't have Venus explicitly as a target, which we think maybe is because everyone was so focused on Venus Express that they didn't think about it. "Why go back to Venus? Much was already mentioned by Larry" Esposito (see my writeup from yesterday). "Understanding why life developed on Earth requires understanding why Venus and Mars are desert worlds. Why does Venus have a strong greenhouse, and Earth and Mars do not? Why did Venus and Mars evolve to a stagnant lid regime, unlike Earth?" A little explanation of this "stagnant lid" business: all planets are hotter inside than they are at their surfaces. This is inherently unstable; heat seeks to escape. The slow way for heat to escape is by conduction -- heat diffuses through a solid material and eventually radiates away from the surface of a planet. A much faster way for heat to escape is through convection, in which the hot material from inside the planet expands and rises upward, actively transporting heat from the interior to the surface. On Earth, we have active plate tectonics driven by (or possibly driving, scientists disagree on this) convection in the mantle. On Mars and Venus, there doesn't seem to be plate tectonics; if there's convection in the interior, it doesn't translate to the surface, and you have a stagnant (i.e. unmoving), conductive lid sitting on top of this hot interior. That's what they mean by a "stagnant lid." Getting back to Håkan's questions about Venus: "How is the evolution of the atmosphere coupled to solid planet evolution on the three terrestrial planets?" Geologists sometimes wish they could ignore the atmosphere, but as Mars Express OMEGA has shown, the kinds of rocks deposited on Mars have depended upon what's happening in the atmosphere; the same thing has happened on Earth; and it's undoubtedly been important for Venus. Håkan showed a concept for a future Venus entry probe; instead of a parachute it's suspended under a "hydrogen super-pressure balloon." Håkan described a proposed 14-day mission, which would allow it to circle twice around Venus. He didn't describe an instrument package in his presentation, but he proposed masses for the various parts: Gondola: 26 kg; balloon: 6 kg; gas tank: 17 kg; parachute: 4 kg; entry system: 38 kg; total mass: 91 kg. "To achieve this mission is a little bit out of the scope of what is available in the short and medium term from ESA's Cosmic Vision, so we need NASA collaboration. There is strong interest from USA, Japan, and Russia, and preliminary contacts with India." But, Håkan pointed out, collaboration with NASA is not as easy as it used to be. "In time of Cassini-Huygens' development we didn't have this ITAR problem, but today it is a big obstacle because it actually demotivates people from collaboration. We all have very bad examples" of ITAR causing problems. ITAR stands for "International Traffic of Arms Regulations," a set of U.S. laws intended to prevent military technology from falling into foreign hands, but which have had a huge, negative impact on the ability of Americans to develop new missions with international partners. "If there is any way this can be changed it would be very beneficial to international collaboration," Håkan concluded. Adriana Ocampo commented, "Missions of opportunity in the Discovery or New Frontiers framework could open venue for that dialogue" between ESA and NASA. Steve Mackwell said to the crowd, "At each meeting at NASA, the issue of ITAR was raised very loud and clear. But I don't know if it will make any difference in the end." Håkan took a moment to talk about a relatively new organization called EuroPlaNet. "EuroPlaNet is an initiative taken by a number of European planetary scientists 2 years ago now. A major problem in Europe is that once we have a mission in space, very little money is invested by the governments to the groups working on the data. They are happy to spend money on the instruments, but not to spend on the scientists, which is a huge waste of money. This group made a proposal to the EU set up framework for collaboration" among European scientists, "and then the money for studies could come at a later stage. So EuroPlaNet was established a year or so ago. One outcome is the first science meeting this September. Then we will see how this develops in the longer term. Thanks to this framework we may be able to get more money from the government to fund research." This brings up an interesting point -- I hear a lot of complaining from people about how ESA does not do as well as NASA as making its data available, either by way of press releases or through archiving of data in a way that other scientists can use. This strange lack of funding for data analysis is one of the reasons that ESA data tends to be less available than NASA data. It's not that the scientists don't want to share, it's that they simply don't get funded to do the work necessary to share. Moving on, Ralph McNutt gave a presentation about what the MESSENGER mission will be able to do scientifically during its Venus flybys. No science will be possible during the first Venus flyby because of bad geometry, so they are focusing their efforts on plans for the second flyby on June 6, 2007. McNutt explained their geometric constraints: "Once we get inside 0.8 AU, we need to keep the sunshade pointed at Sun because of thermal balance issues. We keep the shade pointed at the Sun, and then we can roll about that axis to point the instruments down at the surface." McNutt showed a slide explaining the geometry of the encounter. MESSENGER will approach Venus pretty much from the direction of the Sun (so it will see a nearly fully sunlit globe as it approaches), and then pass a little south of the equator. Just after closest approach, it will cross the terminator (day/night boundary) and pass into eclipse, where the mass of Venus blocks the Sun from the spacecraft. Because of the approaching-from-the-Sun geometry, instruments that are fixed to MESSENGER's instrument deck will observe Venus mostly during the time that they are crossing the terminator, during closest approach. However, McNutt explained the main camera instrument, MDIS, can pivot around one axis so "we've got from freedom." He described the draft plan for MDIS for the encounter: "A flat field measurement; approach mosaic; color photometry; departure mosaic; departure movie; some optical navigation." The laser altimeter, MLA, "will try to range off the cloud decks at Venus; we have some hope of being able to do that, coming across the terminator and into the night side. The approximate ground track comes in over Rusalka Planitia; 164 degrees east, 11 south is closest approach; it will be in that region we'll try to do ranging off of cloud decks. Outbound track goes south of Ovda Regio. In this region we should be able to pivot over the wide angle camera and look back in near infrared." Håkan asked: "Will you penetrate the clouds?" McNutt said that the wavelength of the altimeter was at 1064 nanometers; he wasn't sure. Larry Esposito commented, "There were hazes seen by Pioneer Venus at similar wavelengths up to 80 or 90 kilometers altitude near the poles. They come and go. It will be interesting to see what we see." McNutt agreed. "Regardless of what we actually see, it will be interesting." Takehiko Satoh was the next presenter, on Japan's Venus Climate Orbiter (Planet-C). There wasn't a lot in his presentation that I found to be significantly different from the presentation that Takeshi Imamura gave at the last VEXAG meeting. He did have this interesting tidbit about the launch vehicle, which still has not been chosen (they plan to launch in June 2010 for a December 2010 arrival). "Launch vehicle is still to be decided. We have two possibilities: M-V and H-IIA. Latter is much stronger than former, but even with H-IIA we cannot increase our payload. If we increase science payload we have to change design, which will cause significant delay in schedule. It is kind of unfortunate thing." The people sitting around me seemed surprised about two very different launch vehicles being possibilities for this mission. After this presentation Janet Luhmann asked: "Is there a chance that Venus Express will survive until Venus Climate Orbiter arrives?" Håkan answered: "More than a chance." VEXAG meeting, end: future planning for Venus explorationMay. 2, 2006 | 19:35 PDT | May. 3 02:35 UTC
Next up in the meeting was a panel discussion with Jim Cutts, Ellen Stofan, Janet Luhmann, talking about NASA's strategic planning and what that means for the future of Venus exploration. Ellen Stofan is a member of the NASA Advisory Council Science Committee Planetary Science Subcommittee. I think. I am afraid that I have been unable to work out exactly where all these committees are and who is on which committee and which subcommittee and such, which will make some of the discussion below a little bit muddy. I apologize for that. Ellen: "With the Vision for Space Exploration NASA decided they needed to do 'roadmaps,'" which are essentially long term planning documents. "We hurriedly drafted a solar system roadmap. We received a detailed and helpful review. At that time, the roadmapping process was discontinued. We have this review, but no one was asking for the roadmaps. A decision was made to go ahead and continue revising roadmap. Now," with the restoration of the NASA Advisory Council structure, "there is a group that can receive this roadmap product." Jim: "In January, HQ decided that not only would they like the roadmap to be completed, but they also decided that they actually do need a strategic plan. They wanted to pull this together by May 30. Then two weeks ago, the rules changed, and they wanted the report done in two weeks." (The audience laughed.) "So as Ellen said, what we have done is put together a so-called 'Interim Final Report' [laughter]. We were going to call it the 'Executive Summary' but apparently people don't like executive summaries that are longer than 10 pages. So we decided that rather than rewrite it, we would rename it." (More laughter.) Jim continued: "The other thing was that the President's Vision included a vision to search for life in the solar system. I think the other thing about this is that we've learned something about missions and the cost of implementing missions. While most of the missions in this roadmap would be recognizeable from the decadal survey, in the case of Venus there is a significant change. The group recognized that flagship missions have to be affordable. The group looked at Mars Sample Return, which has receded into the unforeseeable future. This group looked at Venus Surface Sample Return and figured that if Mars Sample Return would be expensive, Venus Surface Sample Return -- a body with a thick atmosphere, you have to raise sample to altitude before injecting into orbit -- would be impossible. For that reason, the group said we could not possibly make a leap from a Venera class lander -- which is probably what is possible under New Frontiers -- to Venus Surface Sample Return. So this led to Venus Surface Explorer." In other words, the decadal plan includes something called "Venus Surface Sample Return" at the flagship level, but reality has intervened and the Venus planning group recognizes it won't happen anytime soon. Instead, they're substituting this thing called "Venus Surface Explorer," which is still a flagship mission. Note that "Venus Surface Explorer" has the same initials as "Vision for Space Exploration," which makes life difficult in the acronym-happy environment of NASA. And it's not very different from the initials of "Venus In Situ Explorer," which is a New Frontiers level mission for Venus that is being talked about -- more about that below. There's also some information about Venus In Situ Explorer in my notes a presentation by Jim from the first VEXAG meeting. In the conversation that follows, most people said "VSE" and "VISE" (pronouncing the latter like "vice") but I'll write them all out so I don't get confused. Ellen: "The unifying theme on the roadmap is habitability. This isn't anything really new; it's just another framing of the science, which of course hasn't been implemented yet. The goal of Venus Surface Explorer is to determine how long ago an ocean disappeared from Venus and how long Venus may have had to potentially nurture life. It's a surface mission but it's going to be combined surface and atmospheric measurements. Everyone has seen how mobility on Mars has changed our concept of Mars, so mobility is important. But mobility drives up cost. A rover on Venus will not get you off one rock unit. So an aeromobility platform is most logical. The mission would include a surface stay time of days or weeks; perhaps it could go up in the atmosphere and cool down." Even if it's not sample return, this is still a flagship mission, and there are other flagship missions being proposed. At one per decade, where would Venus Surface Explorer happen? Ellen: "Where this would come in the queue would be after a Europa mission and likely after some kind of Titan mission. This allows time for both the Venus In Situ Explorer New Frontiers class mission to take place and also time for technology development to take place. But technology development is a catch-22. The farther you put off the mission into the future, the less NASA wants to do technology development; but if the technology is not ready you can't do the mission. We need to keep the pressure up on NASA on technology development for Venus. "Venus Surface Explorer is a vague mission concept that is now being passed on to the planetary science subcommittee. In an ideal world, we would get science goals and measurement objectives that would be developed by VEXAG, which will be used to refine mission objectives. We need these studies in order to refine cost estimates. A critical part of that is having a white paper from VEXAG" on general science goals for Venus. "Also, we need NASA to have a balanced program which includes flagship missions." This last comment refers directly to the lack of funding for the Europa orbiter mission in the current NASA budget. Europa will be the next flagship mission; until it gets going, we won't be going back to Titan, much less to Venus with a big spacecraft. Ralph McNutt commented: "I think the next step is the technology. We need to push for this as a community. Generically, we need a technology development program for all of the missions coming up. I think that is one of the less controversial things that could be done." Larry Esposito: "It isn't controversial but it also isn't new. The challenge is not to write that message but to find a way for the message to be received so that something happens." Jim Cutts: "Yes, we need a technology program. I think more immediately we need a definition of this mission. We know the kinds of things that are going to be required; we need to get this information written down and shared so there's a sense of what is possible and what is not. In case of the Europa Explorer, I think there is a fairly good mission that can be done now, with current technology. In case of the Titan Explorer, I think there is a good mission that needs some technology development. That was the reason more than anything for the ordering of these missions. If Venus had been possible earlier it could have competed with Titan for the second slot. But Venus has an advantage in terms of proximity; even if it's third, a Venus mission would arrive at Venus before the Titan mission arrived at Titan." Robbie Herrick: "Do you envision any precursor missions that are required before Venus Surface Explorer?" Ellen Stofan: "The idea is that the Venus In Situ Explorer mission would be a helpful precursor to Venus Surface Explorer. But I would argue you don't need that mission in order to plan Venus Surface Explorer. Janet Luhmann described how their advice is fitting in to the NASA structure: "When Griffin took office, he basically dissolved the higher-level advisory structure and basically developed the budget you have seen. The NASA Advisory Council is chaired by Harrison Schmitt, an ex-astronaut; they talk directly to Mike Griffin. There is a subcommittee of this, which is chaired by Mike Kennel?" [I am not sure of the name or spelling.] "Sean Solomon is chair of our group, and there's maybe 15 people, a broad group covering all of the solar system. As we understand it right now -- we're all going in pretty cold -- Mary Cleave is not the assigned recipient of our advice -- I'll call it advice, even though using the word 'advice' is loaded right now." I didn't really understand this comment. "-- Mary Cleave will listen in and will presumably benefit from the discussions. "As a matter of fact," Luhmann continued, for this meeting "Cleave will be providing alternative scenarios for the division of funding among the four groups." The four groups she is talking about are the four subcommittees of the science committee (have you had enough of committees yet?) The four subcommittees are: planetary sciences, astrophysics, heliophysics, and Earth science. "There's been a large outcry over R&A and division of priorities. So we are supposed to be presented with a number of alternative scenarios that are a response to the discussion of the cutbacks. We will discuss the merits of redistribution of all the groups. Walls between the four groups will be maintained for the purposes of this discussion, and we'll talk about how it can better be redistributed at this level. One thing I find very confusing is that in recent testimony there has been very strong advocacy by Congress for increasing NASA's science budget, and NASA has said 'no, we have enough science funds, we just need to redistribute it.' I have many questions of that nature that I hope will be discussed by the group as a whole." After this somewhat muddy discussion, Steve Mackwell stood up to recap the discussions from the last VEXAG meeting about the current state of technology readiness for future Venus missions. "What technologies are really required in order to achieve the objectives? At the time of our first meeting, there was a big chunk of money, like 10 million bucks, for this. As I understand it, that is now all gone. Every time we put a proposal in, particularly for going to the surface, the technology readiness kills us right off the bat. So some technology funding is really required. The key issues for us were a very high surface temperature, high pressure, corrosive atmosphere, high-density winds, and the issue of how long you could survive on the surface. "Within those constraints, we also wanted to point out that anything we hope to develop stands a much better chance of arguing for technology development funding if we can make a claim that the technologies are saleable for other missions to other targets. High-temperature, high-pressure are suitable for deep entry probes on gas giants; telecom capabilities are translatable across missions; sample analysis techniques and seismology are also translatable to other terrestrial planet and icy satellite missions. "With that in mind, we broke out the technologies into two different time frames. Short duration -- what we could do better than the Venera landers. Passive cooling systems for about 1 Earth day; 470 C, 90 bars, for a day before the thing cooks; longer duration certainly than 2 hours. Obviously you need high temperature electronics. Balloons would be very useful, Mackwell said. "It's kind of scary how balloons are such a great technology to use in a variety of planetary settings. The Russians did a great job with it at Venus, but NASA seems very scared of balloons, which is a shame because they would be great not only for Venus but also for Mars and Titan. Balloons with vertical and horizontal mobility. "For Venus landed spacecraft, if you're going to go somewhere other than the plains, you'd better have a clear idea of how you are going to land on a small footprint. The most interesting geochemical data are in places like tessera, which are not the easiest places to land. Communications systems: if we're going to put certain technologies on the surface we've got to do it with high telecommunications rates, perhaps with orbiting satellites to relay. For chemical analysis, we need hi-temperature extraction and handling capability. "For long duration missions, we have to look at active cooling systems, and this is the serious technological challenge. High temperature power systems: you want to keep your power systems outside of your active cooling area if at all possible. Long-lived balloons: the question is, do you want to go up and down? It's all very nice for the atmospheric side to be up near the cloud deck, but you can't see the surface. If you want to go down and go up again, you have large, fairly rapid changes in temperature that can tear the balloon apart. "Things we would really like to know: seismology would be absolutely great. It's one of those totally empowering tools, with it, you can learn a lot about the internal dynamics of the planet. But there are all sorts of issues with building a seismometer that would work on Venus. Ground coupling, surface winds which will buffet the thing, temperature and pressure issues, triggering -- if you leave it running all the time it collects a huge amount of data. Several seismometers at different places would be great, but this is not a cheap thing to do. Landing a single seismometer will tell you if Venus is active or not, but it will tell you very little else. Heat flow measurements require drilling and high-temperature electronics. This changes the local thermal profile, and that takes a long time to settle down. "We referred all this to Jim [Cutts], who was going to get all that money to work on this. It didn't quite happen that way, but this is a living document" (you can download the document, "VEXAG Report on High-Priority Technology Development Requirements," from the VEXAG website). "This document we should regard as fluid; we modify as we go along. At one meeting a year we should revisit it and modify it." Kevin Baines: "If you want a long-lived balloon you then want mobility -- propellers, et cetera. So is that part of the document?" Mackwell said it wasn't yet; and "That's why we need to make sure these are living documents." Finally, Mackwell ended, he said, with a plea. "There's a lot of stuff going on in the planetary science community right now. There's a lot of pressure because of the damage to the R&A program, the damage to missions, flagship going offline and things like that. We have to be very, very careful at this point to be a community. Not just a community of Venusites or even planetary scientists but actually NASA scientists. We've got to avoid things like the Earth observing community saying 'what are we doing at Mars? we need to spend money on Earth.' We've got to represent a united front. Griffin is not going to move money back into NASA science. We've got to make sure that Congress makes sure that we have a viable science program; we have to make a plea for science, not for our particular branch of science. Every time I've seen that done in the past, everybody loses." The last talk I've got notes on is one given by Gregg Vane on a recent meeting held in Washington, D. C. on "lessons learned" from Principal Investigator-led missions. Vane began: "Competed missions are certainly factoring large in our plans to explore Venus, whether we like it or not." He commented that all of the presentations are on the meeting website. Vane continued: "Paul Hertz gave some interesting numbers. Based on a 12-year history, 22 missions had launched (24 including Calypso/Cloudsat). Of those, only 2 have failed. 10 are in operations at the moment; there are 10 in development; the rest have already completed their missions. Something on the order of 600 proposals have been received and evaluated, so they are able to go back now to see what the distribution is between scientific merit, feasibility, and the technical management/cost part ("TMC"). My own experience is that generally the science scores are high because it's a very creative community and they know how to identify good problems. So even though the Discovery announcement says science is the most important factor, the final 30% is generally what makes or breaks a proposal, so the TMC part is actually very important. A third of these proposals have been noted as high-risk, one third as medium, one third as low. In order to be selectable, you have to be low-risk or medium -- as long as it is a low to medium. So a third of the proposals are immediately off the table, and a good fraction of another third are also off the table. "High risk factors were all pretty evenly distributed. The first one is high cost risk; root causes were lots of inventions required, schedule, things which required more money than they thought the program had available. So if your reserves were too low for your level of risk, then you're high risk. Another one was poor technical design margins in terms of mass and power reserves. Instrumentation was another one; there were three key areas. First and foremost was instruments which require new capabilities or technologies which are not yet mature. In the early days of Discovery they were much more open to this, but now they are looking at it being much more mature, even in the early phases, so technological readiness is really a big deal. So instrument development is essential for Venus. A fourth area was system engineering; without a good plan they doubt the team. And the final area was issues relating to both management and schedule. In the case of schedule, not enough detail; number one cause of high risk for management was a selection of partnership whoise previous history was not clear -- wasn't clear they were really qualified to contribute. Another big one was complexity of organization, a lot of partners, where there's not definition. "We have a particular challenge with Venus because it is naturally a challenge to go to. If you're going to go to a high-risk target, you have to do everything you can to knock down the risk elsewhere. It's a fact of life and I don't see it changing, even within the professional lifetimes of the people in the room." So that's it for my notes -- and this was all in the first day of the meeting. I wasn't able to attend the second day of the meeting, which included breakout sessions in the different disciplinary areas: atmospheres, geology/geophysics, and technology development for in-situ exploration. Hopefully we'll all be able to see the results of those discussions in documents that will appear presently on the VEXAG website. I'd like to get back to talking about cool science and pretty pictures, and I will -- I have some really great Mars Express stuff that I want to share, and I'll do that tomorrow. But on Thursday, it's back to politics and plans for me, with the meeting of the Outer Planets Assessment Group. That one is going to be much more political, in fact. I'm afraid I'll be in a little bit over my head, but I'll do my best to write down everything I hear even if I don't understand it all, and report it here. |
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