OPAG Presentations Posted But..

Ellen Stofan's presentation on a Discovery class Titan lake lander isn't among them. A friend has seen the presentation, so it was apparently made. Perhaps she didn't want it posted for competitive reasons. A Titan mission affordable in a Discovery budget would be a very strong competitor (assuming that the technical risk is acceptable.

You can go here to look at the presentations: http://gishbar.blogspot.com/2009/04/opag-spring-meeting-presentations.html

Or here to read Jason Perry's summary: http://www.lpi.usra.edu/opag/march09/presentations/

Several Interesting articles

I managed to find an internet cafe in a South African national park. A quick survey of several websites found several interesting articles you may want to read.

Aviation Week has an article on the Decadal Survey. The article lists the focus groups that will prepare white papers on the current state of the science and the recommended missions to address key questions. "The survey team will consist of six panels - a steering committee headed by Squyres, and panels covering the inner planets (Mercury, Venus, the moon); Mars; the outer planets (including magnetospheres and rings), the satellites of the outer planet, and primitive bodies - asteroids, comets and the Kuiper Belt." http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/Decadal041609.xml

A quick overview of the upcoming Lunar Reconnaissance Orbiter http://www.msnbc.msn.com/id/30316051/

NASA Watch has a summary of several articles on the budget pressures at NASA. The summary: Too many goals, not enough budget, continued problems meeting goals. http://www.nasawatch.com/archives/2009/04/congressional_b.html

Space Politics has a similar summary plus some lively discussion. http://www.spacepolitics.com/2009/04/16/cbo-costs-out-various-nasa-budget-options/

Space.com has an article on preliminary study for a possible lander for Ceres. If the Dawn mission finds strong evidence for water as is expected, then this asteroid could become a focus target for future missions. (Unfortunately, the magnetometer was dropped from the mission to save money, so we can't get direct confirmation of a buried ocean.) http://www.space.com/scienceastronomy/090416-am-ceres-lander.html

Good piece on Jupiter Europa Orbiter

Ted Stryk has an excellent guest blog entry on the Planetary Society's website on the Jupiter Europa Orbiter. http://www.planetary.org/blog/article/00001911/

Intermittent Postings for Next Month

Tomorrow I leave on a month long trip to Africa, half work, half vacation. Unfortunately this will mean that my access to the internet will be haphazard. I have several stories I'll write on plane trips and post as I can. Bruce Moomaw will keep an eye out for news and I'll post his summaries whenever I find an internet cafe.

In the meantime, you might want to keep an eye on this site (http://www.lpi.usra.edu/opag/reports.html) to see if the presentations from the OPAG March meeting get posted.

Tidbits

Several small items today:

More Ice on Mars - The journal Science has an article about how studies of small fresh craters on the surface of Mars have revealed pure ice beneath a thin soil surface.  "Spanning northern latitudes of 43° to 56° (Phoenix landed at 68°N), five new craters were a few meters in diameter, a few decimeters deep, and floored with a bright, white material that looked like clean ice."  This discovery brings two thoughts to mind.  First, we still know so little about Mars.  A series of moderate price missions to increase our knowledge seems very sensible to me (as opposed to moving quickly to a $6-8B sample return).  Second, a Phoenix-like lander with a drill that could bring up samples from 1-2 m beneath the surface would be a great vehicle to explore this northern ice.  If the mission were powered with Advanced Stirling Radioisotope Generator (ASRG) fuel sources, it could potentially study the surface for a period of a year or two, giving it the luxury of time that Phoenix did not have.

Ice within a small crater in the northern plains of Mars

MetNet - In the comments, Ted Stryk writes, "MetNet's precursor mission did not get bumped by the Chinese orbiter - there is room for both. Finland had funding problems and couldn't get the penetration ready for 2009. The plan now is a launch of one or two penetrators as a stand-alone mission to be launched on a Volyna rocket in 20011. However, if Phobos-Grunt is indeed delayed to 2011, it may indeed carry the precursor mission."  That is good news.  You can check out http://metnet.fmi.fi/ for more information on this Finnish Mars penetrator.

Finnish MetNet Mars Penetrator

Europa Small Landers - Anonymous said [about Europa penetrators and hard landers]: "Very interesting, but I wonder why no mention of any type of lander/impactor/penetrator was made in the EJSM Joint Summary Report. The Titan mission had 3 in situ elements...I always wondered why the Jupiter team left any mention of in situ out of their reports."  

My understanding is that their were a number of ground rules for the Flagship studies.  For example, the ESA Titan in-situ craft had to be carried by the American orbiter.  Similarly, the Europa orbiter could not include any lander.

Now that the destination for the next Flagship has been selected, my understanding is that a lot of variations can be studied.  I remember reading somewhere that small landers provided by a non-American party can be considered.  These small landers should be cheap enough that an individual European nation, Japan, Russia, India could provide one.  

There are issues of technology that can survive the radiation field at Europa.  While the lander may only need to survive a few days of independent operation, it will also accumulate radiation exposure through the entire period leading up to its release.  The lander(s) could be carried in shielded tubes or boxes (essentially, vaults) but that weight might add up quickly.  

Mars 96 - Anonymous wrote, "Didn't Mars 96 have two penetrators onboard? IIRC, these were supposed to use the inflatable descent system developed by Lavochkin."  Good catch.  I had forgotten about the two small landers and penetrators carried by the ill-fated Mars 96 mission.  Wikipedia has a nice entry summarizing the mission.  http://en.wikipedia.org/wiki/Mars_96

Mars 96 Martian penetrator from Wikipedia

Europa Hard Landers and Penetrators

I have a new post on Europa Hard Landers and Penetrators at http://futureplanets.blogspot.com/2009/04/europa-hard-landers-and-penetrators.html

Russian Europa Lander

See http://futureplanets.blogspot.com/2009/04/russian-europa-lander-concept.html for the blog entry. Blogspot lists posts in the order written, not published, so this latest entry isn't at the top of the page.

Russian Planetary Plans

In preparation for a trip, I've been writing blogs ahead of time. It turns out that blogspot lists the entries in order of writing, not posting. So just in case you check in here to see what's new, click here to see the post on future Russian planetary missions.

http://futureplanets.blogspot.com/2009/04/last-several-posts-on-this-blog-have.html

Europa Hard Landers and Penetrators

This blog entry continues looking at presentations from the Russian-sponsored conference last January on Europa landers. The last entry looked at a proposal for a highly capable lander. This entry looks at proposals for two smaller landers.

Concepts for planetary landers fall into three classes. The first is for soft landers like the Mars Phoenix or MER rover craft. Combinations of parachutes, rockets, and or airbags soften the landing force. As a result, highly sophisticated craft and instruments can be delivered to the surface.

The other two classes of landers only partially spell the energy of descent and as a result do what can be termed as a controlled crash with style. Hard landers simply hit the surface, bounce and eventually come to a stop. Penetrators look like small rockets and burrow, nose first, into the ground and use the friction of ground penetration to stop some distance beneath the surface. Both classes of landers require hardened instruments and system electronics, which limit their capabilities. There isn't room for complicated masts to hoist imagers or robot arms to gather carefully identified samples for analysis. Instead, one or two simple instruments are carried. The landed mission lasts until the small batteries are exhausted.

The conference had presentations proposing both types of landers. The hard 'stop and drop' lander was discussed by a team from the Jet Propulsion Laboratory, one of NASA's centers. The team presented a number of possible instruments, but focused on an accelerometer (presumably to study the surface hardness but possibly also to measure some seismic activity), a gas-chromatograph/mass spectrometer, and a camera. The goal would be to conduct measurements for a full Europan day (84 hours) plus an additional 12 hours for additional data relay to the orbiter. Approximately 14 to 24 Mbits of data would be returned, depending on the altitude of the orbiter.

The penetrator presentations was done by the UK Penetrator Consortium. Here a small penetrator, perhaps 60 cm in length, would carry around 2 kg of instruments. Possible instruments include a seismometer, mass spectrometer, soil/environment package, simple surfve and descent cameras. Penetrators are used in a number of terrestrial studies, especially when dropped from airplanes. They have been studied for planetary missions for decades. Except for the doomed Deep Space 2 probes, none that I remember have flown. The Japanese space agency came close to flying penetrators to the moon, but canceled the mission due to development problems.


The hard lander presentation showed that for the nominal 2020 launch date and current mass estimates for the Jupiter Europa orbiter (JEO), 260 - 320 kg spare mass margin. (Note: spacecraft have a nasty tendency to grow in weight as design progresses and right now the JEO exists only as preliminary computer files.) No weight estimate is given for the hard lander plus descent system; presumably it would fit within the mass margin. One chart suggests a lander mass of 100 kg plus 35 - 65 kg of propellant. The penetrator presentation showed a mass of 30 kg or less for the penetrator and descent system. This would potentially allow several penetrators to be carried.

Editorial Thoughts: A number of problems exist with hard landers and penetrators. First, they require miniaturized desent craft that kill the orbital speed and possibly some of the descent speed. In the case of the penetrators, the descent craft also must ensure that the penetrator is pointing down for its impact. Another issue is the tight space in within the landers or penetrators -- every system must be miniaturized and hardened against impact, which reduces capabilities (including battery life). It is also hard to build miniaturized sample devices to bring material into the craft for analysis. This is especially true for hard landers which must be capable of acquiring samples no matter which side ends up being in contact with the surface. Europa would also poise a special problem for small surface landers -- there's not much mass to provide shielding against the radiation that will be present. Here, penetrators would have the advantage because the surrounding ice would provide some shielding.


Neither presentation gave more than passing mention to the radiation environment, suggesting -- as with the soft lander discussed in the last blog entry -- that these are preliminary concepts. I have my doubts about whether either would actually fly. On paper, the landers seem reasonable. As we learned from the Deep Space 2 and Beagle 2 landers, however, building and testing craft that would actually survive is hard and requires substantial financial resources.

However, should either concept make it to flight, I have a slight preference for the penetrator. I believe that it would be the lighter of the solutions, perhaps allowing 2 -3 to be carried. I suspect that crashing into the surface of Europa could be fatal a high percentage of the time. Redundancy would be nice.

If a lander is designed for Europa, then in theory it could be modified to also fly on ESA's Jupiter Ganymede Orbiter (JGO). The primary difference that I see would be the need for a heftier descent system to account for the greater mass of Ganymede.

Resources:

Hard lander presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/Hand_ELW.pdf

Penetrator presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session7/Gowen_ELW.pdf

Deep Space 2: http://en.wikipedia.org/wiki/Deep_Space_2

Beagle 2: http://en.wikipedia.org/wiki/Beagle_2

Russian Europa Lander Concept

At the Russian sponsored Europa lander meeting last January, the Russian space agency presented a concept for a Europa orbiter. This presentation focused on the spacecraft hardware. Other presentations looked at possible scientific instruments.

The mission outlined is an ambitious one. The mission consists of a series of stacked stages and spacecraft. The first stage would be a solar electric propulsion unit that would help deliver the orbiter stack to Jupiter following a three years cruise. A propulsion stage brakes the stack into Jupiter orbit where gravity assists allow the eventual Europa orbit insertion in early 2024. The stack then separates into a Europa orbiter and a highly capable soft lander.



The science potential of the mission could be substantial. During the Jupiter system tour, the spacecraft would perform thirteen Ganymede and four Callisto flybys. The orbiter would carry 50 kg of scientific payload. That is sufficient for capable studies during the flybys and while in Europa orbit. The lander would host 70 kg of instruments. Both the orbiter and lander would be powered by RTG's, providing the mission with considerable operational flexibility.



Editorial Thoughts: The mission concept certainly is ambitious. Left unmentioned is the elephant in the room for any Europa mission -- the radiation environment. This seems a curious oversight. NASA has spent a decade developing technology that can withstand the radiation at Europa. Perhaps considerable work is underway to develop the technologies to solve this problem and simply wasn't included in the presentation. It appears that the time in Europa orbiter may be limited to a small number of months, which would help. Without this issue being addressed, however, I am left wondering whether or not this mission is merely a pipedream or a serious proposal. If anyone reading this blog attended the mission, your clarification would be very welcome.

Even without the issue of radiation, the mission is technically ambitious, especially for a first flight by the Russian space agency beyond the orbit of Mars. The presentation does point out that the Europa lander concept builds upon technologies that will be used in the Phobos sample return and the lunar lander missions. I don't doubt that the Russians are capable of developing the technologies needed -- they are the only nation to have landed on Venus. The Venus program, however, built up capabilities over time with missions becoming more sophisticated as technologies were developed and concepts proven. Going directly from Phobos and the lunar surface to Jupiter and the surface of Europa seems a large step.

I also think that the time frame for the mission seems wrong. It would seem more logical to me to have the lander arrive after NASA's Jupiter Europa orbiter has mapped the moon and identified both safe and scientifically interersting locations. This would delay arrival to 2029. The extra five years also could provide more time for the Russian space agency to hone the technologies for a Europa mission.

I hope that my skepticism is unfounded. A Europa lander would be an excellent addition to the 2020's exploration of the Jovian system.

Resources:

Europa lander concept presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/martynov_ELW.pdf

Website with all presentations. Look towards the bottom for a number of presentations on potential instruments. http://arc.iki.rssi.ru/conf/2009elw/presentations/

Next Steps for New Frontiers and Europa Jupiter System Mission

NASA publishes a weekly planetary exploration newsletter. This week had two announcements about the next steps for the selection of the next New Frontiers mission and the Europa Jupiter System Mission. The notes are short enough that I'll reproduce them here.

The New Frontiers mission selection slipped as a result of the Mars Science Laboratory. NASA wanted to understand the impact of MSL's cost overrun before preceding. From the dates in the notice, it appears that the schedule has slipped out about two months. That would put the selection of 2-3 candidate missions for further study around January of next year. Following Phase A studies of the candidate missions, selection of the mission to be flown would occur early in 2011. You can see a list of the acceptable mission targets in the poll on the right side of this blog. The draft announcement also describes the target missions.

NASA's announcement:


"The National Aeronautics and Space Administration (NASA) Science Mission Directorate (SMD) is releasing a NASA Announcement of Opportunity (NNH09ZDA007O), New Frontiers 2009. NASA expects to select up to three New Frontiers mission proposals for a 10 month Phase A study. Following evaluation of Phase A reports, NASA expects to approve one New Frontiers mission to proceed into Phase B and subsequent mission phases. Launch is to occur no earlier than late CY 2016 and no later than CY 2018. The proposed missions must address the science objectives of one of the eight mission concepts identified in the National Research Council's 2007 report, "Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity."


Europa Jupiter System Mission:

"The Europa Jupiter System Mission is first priority for the OuterPlanet Flagship Missions and involves the NASA Jupiter Europa Orbiter, ESA Jupiter Ganymede Orbiter, and possibly other elements, such as a JAXA Magnetospheric Orbiter. In addition to Europa and Ganymede,substantial Jupiter system science will be conducted.

"The science objectives were defined (http://opfm.jpl.nasa.gov/library/)
and the mission is in the next stage of development. Goals include
strengthening the science return, encouraging planetary community
involvement, and ensuring support by relevant space agencies. Workshops
are planned to assist potential instrument providers for addressing
radiation and planetary protection issues, with the first workshop
July 15-17 at the Applied Physics Laboratory, Maryland. In addition,
Jupiter-system sessions are planned for near-term meetings, such as
the European Planetary Science Conference this fall in Potsdam."

Russian Planetary Exploration Plans

The last several posts on this blog have focused on issues of management and budget. It's time to return to hardware and flight missions. The next several blogs -- assuming no breaking news -- will focus on information in presentations from a Russian-hosted conference on Europa landers.

Today, though, we'll start with an overview of the Russian planetary exploration program. In the United States, the Russian space program receives little attention. I was delighted to find a "very short overview" of their program presented at a conference on Europa landers last January. Information on the planned astronomy missions was indeed a very short overview. There was, however, a good amount of information on their upcoming mission to the Martian moon Phobos and short summaries of future missions.

Phobos appears to be a D-type asteroid captured into Martian orbit. Previous gravity measurements by other craft have shown that its density is too low to be a solid object. It instead appears to be a rubble pile.

The Phobos Sample Return mission (also known as Phobos Grunt, which means "Phobos soil") due to launch this fall will be an ambitious mission. Its primary goal will be to collect and return a 0.2 kg sample from the surface of Phobos for analysis in Earth laboratories. The return craft will also carry an experiment prepared by the Planetary Society that will take samples of micro-organisms to Phobos and back to Earth. The goal of this experiment will be to assess whether micro-organisms can withstand the rigors of space travel with the sample canister playing the role of a simulated meteoroid. If the organisms survive, then it is possible that life could have passed from planet to planet in meteoroids blasted off their surfaces by large impacts.

Phobos Sample Return spacecraft.

In addition to the sample return, the mission will study Phobos with an array of remote sensing and in-situ instruments. The presentation doesn't provide details of the instruments except the gas chromatograph, which appears to be detailed as an example of the sophistication of the instrument suite. I found relatively little detail on the mission on the web. From the instrument list, it appears the the spacecraft will conduct remote sensing of the moon prior to landing. Following the landing, according to Wikipedia, the spacecraft will collect surface samples and launch the return craft on its journey to Earth. The lander will then study the soil with a variety of instruments over a period of a year.

The mission will also carry a small Chinese orbiter that will study the interaction of the solar wind with Mars' atmosphere.

Brief information was also given in the presentation for several other planned planetary missions:

• The Luna-GLOB mission will launch in 2012 and orbit the moon. It will implant an unspecified number of penetrators into the moon's surface for network studies
• The Luna-Resource mission will land a rover near one of the lunar poles for surface studies. Since the artist conception shows solar panels, it appears that the mission will not target one of the permanently shadowed lunar craters.
• A Venera-D mission is listed for 2016. The slide lists an orbiter that would study the atmosphere and climate, balloons (the plural is used), and a lander.
• A MarsNet mission for 2016 would be done in cooperation with Finland. That latter country would provide a number of small penetrators to establish a network of instruments on the Red Planet.

A roadmap slide showed the schedule for the missions. The Phobos sample return and the two lunar missions were shown as firm dates. The other missions had their launch dates covered with a question mark indicating that they may not yet be committed missions.

Editorial Thoughts: It's good to see Russia returning to planetary missions. The Phobos sample return promises to deliver a wealth of information. According to Wikipedia, the schedule for the 2009 launch is tight. A backup launch date would be 2011.

As I recall, the Phobos mission originally was to carry a prototype of the Finnish MarsNet penetrator. Apparently that has been replaced by the Chinese orbiter. I am a fan of the MarsNet penetrators, and am disappointed to see testing of the landers delayed.

The Venus mission seems to me to be in the early conceptual stage. The list of vehicles and science goals is quite long. The U.S. Venus science community has been putting together a proposal for a similar mission that would cost ~$3B. Even assuming less ambitious goals for the Russian mission, it still seems like quite an undertaking for a launch date that is just 7 years away. If any of the readers of this blog have more information on this, I hope you will post them in the comments.

I do have one armchair explorer hope for the Phobos mission. I would love it if the landing site provided a view of Mars on the horizon. Given Phobos' low orbit, the Martian surface would dominate the sky. That would be a picture worth hanging on the wall.

Possible landing sites (Mars Express image)

Resources:

Russian presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session1/zelenyi_ELW.pdf

Phobos background (Wikipedia): http://en.wikipedia.org/wiki/Phobos_(moon)

Air and Space article on Phobos-Grunt: http://www.airspacemag.com/space-exploration/Mission_Possible.html?c=y&page=1

Phobos-Grunt (Wikipedia): http://en.wikipedia.org/wiki/Phobos-Grunt

Chinese Yinghuo-1 orbiter: http://www.planetary.org/blog/article/00000985/

Planetary Society's LIFE experiment: http://www.planetary.org/programs/projects/life/

Some Thoughts on Cost Overruns

Over the last several days, I've been thinking about the interview with the head of NASA's science program, Ed Weiler, posted by the journal Science. (See here for a summary of the accompanying article.)

Some of his thoughts have stuck in my mind: "Most "cost estimates" that go to the [National Research Council]-and I'm speaking from 31 years of experience with decadals-come from NASA centers or contractors; they don't come from NASA headquarters, and they don't get reviewed by NASA headquarters... Scientists cannot do cost estimation, I'm sorry, they're not trained for that... Anybody who compares a decadal cost-survey estimate to anything in reality, well, I have no comment on that kind of person... And if you think we don't get mean with contractors, go talk to some of the CEOs who've sat here and got an earful from me."

I have known CEOs of several of companies, including some on the Fortune 100 list. Their egos are quite big enough to take a tongue lashing from Weiler. And what is NASA going to do to punish these companies? Tell JPL that they can't build any more planetary spacecraft? Who else has expertise in a number of critical areas? Or tell Lockheed-Martin or Boeing that they can't bid on any more NASA contracts? There are only 2 - 3 companies big enough to support these missions.

Another part of the Weiler interview also got me to thinking. He said, "A billion dollars doesn't buy much any more, it buys you 3500 major aerospace engineers for a year."

The planetary community is starting another Decadal Survey to prioritize the next decade's missions. (They are planning on significantly improving cost estimates.) My best guess at NASA's purchasing power for the next decade -- extrapolating from current budget and guessing that there may be years of frozen budgets as there were the last decade -- is that NASA will have $6-8 billion to spend in 2011 - 2020 on new missions in today's dollars.

Here are some costs for missions that I have gathered over the last year stated approximately in today's dollars (figures in millions of dollars):

Jupiter Europa Orbiter	$2,700
Minimum Mars Science Orbiter	500
Mars Network	1000
Mars Mid-range rover	1400
Comet sample return	1000
New Frontiers (each)	650
Discovery (each)	375

In addition to these missions, NASA is likely to spend $200M+ in this timeframe developing the Mars Maven orbiter (2013 launch) and perhaps $200 to support ESA's ExoMars mission.

Here's what one line up of missions might look like:

		cumulative
MAVEN & ExoMars	400	400
2 Discovery	750	1150
2 New Frontiers	1300	2450
Minimum MSO	500	2950
Mars mid-range rover	1400	4350
Jupiter Europa Orbiter	2700	7050

If the mission costs are approximately right and there are no major cost overruns, then this is a rich mission set. Mars receives several new missions, Jupiter and Europa finally get their return visit, and there are some smaller missions to provide balance. On the other hand, there's not a lot of room for error here and still maintain a balanced program. If the mid-range rover and the Jupiter Europa Orbiter, for example, overrun by 50% each, the Discovery and New Frontiers missions become unaffordable.

NASA Cost Overruns

The journal Science (April 3) has a two page article on the problem of cost overruns in NASA science missions. The article quotes the head of the science program, Edward Weiler, as saying that the thing that prevents him from starting " 'sexy science" missions is all the "new sexy missions started 5 years ago that are costing more than they were supposed to... When I walked into this office, there were a lot of promise made out there, and [the science] communities were pretty happy... Over a 10-year period there were $6 billion of promises made [in planetary sciences] that could not be met.' " Weiler needs $900 million more each year just to keep up with missions on the Earth science roadmap.

The article notes the James Webb space telescope that has grown from $1B to $4B, the $600M Mars Science Laboratory has become $2.2B, the Glory mission to sutdy aerosols and black carbon in Earth's atmosphere is 50% over budget, and the Solar Dynamics Observatory is three times its initial cost. An independent study showed that 25% of NASA's mission went at least 40% over budget.

The article notes that there are no simple answers. If there were, they would have been implemented already. The existence of an "iron triangle among NASA centers, lawmakers, and contractors," is part of the problem. Missions developed by a NASA center are protected by the local Congressional delegations. Every member of the triangle knows that NASA will cave when faced with cost overruns. Missions that have been approved are protected at the cost of starting new missions.

Weiler blames scientists on the Decadal surveys for believing lowball cost estimates. Scientists reply that their estimates come from both NASA and independent assessors.

The process of preparing cost estimates will be much more rigorous in the next round of Decadal Surveys. (Astronomy and planetary surveys are in progress.) Any mission that isn't already underway goes back into the process to be re-evaluated.

Science also has a interview with Weiler posted on its website. A choice tidbit:

Weiler says that the science of the Titan Flagship mission was absolutely compelling, but that the Titan mission was "more or less in the blueprint stage. When we looked at a cost schedule and technical readiness, it was a slam dunk [in favor of Europa]."

Editorial Thoughts: I'm not sure that the iron triangle isn't an iron quandrangle. The science community -- or at least those whose missions become started -- also benefits from lowball estimates that become protected missions.

I would like to think that better run Decadal Surveys will solve the problem. I expect that missions proposed in the next round of Surveys will be better costed. Two issues will remain, I believe. First, estimating the costs of complex, one of a kind missionss is hard. Second, if we knew the true costs to begin with, we would still end up with fewer missions. Our expectations would simply be more realistic.

In my mind, part of the solution could be to include a mix of mission costs within the high priority list of recommended missions. For example, the planetary Decadal Survey could say that flying three Discovery and two New Frontiers missions in the next decade must be budgeted first. Then remaining funds can go to Flagship missions. With this approach, its likely that 4 - 6 missions will fly in the next decade, even if the highest ranked Flagship mission overruns its budget and must be delayed.

Resources:

Link to Science article (will cost $15 unless you have a subscription) http://www.sciencemag.org/cgi/reprint/324/5923/34.pdf

Link to Weiler Interview (appears to be free) http://www.sciencemag.org/cgi/content/full/324/5923/34/DC1

VEXAG Part III - Long Term Surface Measurements

A high priority goal for Venus exploration has been to enable long term stations on the surface of that planet for meteorology and seismic measurements. The heat and pressure of Venus has seemed to put this goal out of reach. At the last VEXAG meeting, a possible solution was presented.

I'll let those with an engineering bent look at the presentations for details. Basically, the solution is to return to instrument concepts from before the advent of current, electronics based solutions. Modern instruments on Earth, or that would be sent to less hostile planetary surfaces, use electronics to hold a reference mass nearly motionless relative to a reference frame. In previous eras, geophones performed a similar function in which a coil generating field was affected by the motion of a magnet. Magnetic materials apparently are questionable for the temperatures and pressures of Venus, so a proposed instrument would use a high temperature variable inductor.

Power would be supplied by a sodium sulfur battery that, with some moderate technical development, could power a station for over a half year, the baseline requirement. Data storage apparently wouldn't be possible within the station. Instead, any data would be relayed real time to a orbiter. A series of stations would be placed on the surface so that one or more would always be in communication with the orbiter.

Basic meteorology measurements would be enable by the same approach of using older technology approaches, updated to function on the surface of Venus.

Editorial thoughts: The presentation lays out a technology development plan to make long-lived (at least within the context of the surface of Venus) measurements possible. Costs of the stations was not addressed. However, Venus is a sister planet with a hellish twist. Understanding the deep interior would allow us to better understand how terrestrial planets evolve and function. I hope that this approach is realistic. It would be nice if it could be afforded within a Discovery class mission. If not, it may be a possible add on to the proposed Venus Flagship proposal that will be discussed in this blog in about a month when the final proposal report is published.

One could imagine a hybrid lander/station. Part would be designed to last for an hour or so on the surface and could provide descent images and surface images. Perhaps basic surface chemistry measurements could be made. After that portion of the lander fails as a result of heat and pressure, a longer lived network station could make measurements for half a year, perhaps significantly longer.

Resources:

Two slide overview of approach http://www.lpi.usra.edu/vexag/feb2009/presentations/venusSeismologyKiefer.pdf

Long presentation looking into details of technical approach http://www.lpi.usra.edu/vexag/feb2009/presentations/seismolgyMeteorlogyHunter.pdf