Monday, September 24, 2012

A More Awesome Europa Clipper Proposal

One of NASA’s key advisory committees, the Committee onAstrobiology and Planetary Science (CAPS), is meeting today and tomorrow.  My schedule permits me to listen to just part of the meeting, but I’ve arranged to listen in to two key portions: Today’s update on the Europa Clipper proposal and tomorrow’s presentation on the future Mars roadmap.  (Casey Dreier of the Planetary Society is also blogging on the meeting and covers sessions I couldn’t attend.)

The Europa Clipper is one of three mission concepts to come out of the demise of NASA’s Jupiter Europa Orbiter proposal that would have cost close to $4B.  That sticker shock led the Decadal Survey to recommend that NASA investigate cheaper mission alternatives.  In previous posts, I’ve describe the minimalistic orbiter and a multi-flyby spacecraft (now dubbed, Europa Clipper) and concepts for Europa landers.

Both the orbiter and the Clipper concepts have been estimated to come in at below $2B, meeting the challenge of the Decadal Survey.  The science community has favored the Clipper proposal with its richer instrument set over the orbiter.  (The lander concept is both much more expensive and requires either the orbiter or Clipper mission to scout for safe and interesting landing sites.)  In today’s CAPS meeting, an update to the Clipper concept was provided.

The previous Clipper concept from last spring focused on science best done by a highly capable spacecraft encountering Europa briefly during approximately 30 flybys:

  • Characterize the structure of the icy shell with an ice penetrating radar
  • Explore the chemistry of the subsurface ocean and the interaction of the ice with Jupiter’s radiation field by examining the composition of materials brought to the surface and subsequently modified with an infrared spectrometer and a neutral mass spectrometer
  • Investigate the relationship of surface structure with the ice shell structure and surface composition through imaging with a camera

Clipper Science goals (click on image for larger version).  Color coding shows the original goals and the new enhanced goals.  From presentation at CAPS meeting.

This minimalistic instrument set left key goals to a future orbiter mission that would use measurements of the interaction of Jupiter’s magnetic field with the ocean to directly explore the ocean’s characteristics.  (Similar, but less precise measurements than those planned for future Europa missions allowed the Galileo spacecraft to all but prove the existence of Europa’s ocean).  Also left to an orbital mission were the precise gravity measurements that would measure the amplitude of tides in the icy shell that would provide a second validation of the existence of the ocean and also study the tidal forces that restructure the icy shell.

The Clipper definition team listened to a request from the scientific community to enable the magnetic and gravity measurements from a flyby spacecraft.  The new baseline proposal has added a magnetometer, a Langmuir probe (which allows scientists to separate the changes to the magnetic field from Europa’s ocean from transient changes caused by variations of the local plasma field), and a dedicated, gimbaled antenna that can remain pointed at Earth during flybys to allow precise radio measurements.

In parallel, the studies of possible Europa lander missions lead the Clipper definition team to realize that any future landing missions would need high resolution, stereo imaging of possible landing sites.  A thermal imager would also help characterize the size of icy blocks at the surface.  (Small particles the size of gravel would cool fastger following sunset or heat up faster following sunrise much faster than say boulder sized ice chunks.  A lander needs a site with small particles on the surface, not boulders.)  To enable a future landing mission (which may be a decade or two after the Clipper mission eventually flies), the definition team has added a high resolution camera and a thermal imager to the payload.

Unfortunately, these additional instruments and their integration into the spacecraft raised the estimated cost of the Clipper mission from a bit under $2B to approximately $2.2B.  However, the definition team also has begun looking at replacing the previously planned plutonium-based power supply with solar panels.  The early analysis is positive, and if it can be done, the net savings bring the Clipper mission’s cost (not including the launch vehicle) back down to around $2B.

Solar-powered version of Clipper concept.  Recon refers to reconnaissance imaging to characterize future possible landing sites.  From presentation at CAPS meeting 

Editorial Thoughts: Wow!!

This will be an awesome mission.  Unfortunately, NASA’s projected budget, which covers the next five years, doesn’t provide funding for this mission.  I can be pessimistic and think that a dedicated Europa mission has been a top priority for over a decade and is no closer to being funded today than in 2000.  However, the quality and cost of this mission gives me hope:  Excellent(!) science without requiring new technology development (as most previous Europa mission proposals did) for a cost well below what the Mars Science Laboratory Curiosity cost (especially when Curiosity’s costs are inflated to the 2015 dollars used for all of the Clipper cost estimates). 

Big science missions in the past often have required a decade or two to go from concept strongly supported by the science community to a funded project.  (Curiosity was one of the rare exceptions.)  We now have a crisp, credible proposal on the table.  Things are tough now, but they have been before (some of you may remember when NASA’s planetary program almost was shut down around 1980).  Tonight, at least, I’m optimistic that Clipper or a descendent of the proposal will be funded, perhaps a decade from now.

In the meantime, if there are any multi-billionaires who read this blog, can you spare a couple for a good cause? 

Sunday, September 23, 2012

Not A Bias

Having read a number of forums and the comments on this blog, I know that a number of readers (I as was) were disappointed that the TiME Titan lake lander was not chosen for the next Discovery mission.  It’s now likely that I won’t see another mission to Titan in my lifetime.  Several blogs wondered if NASA had a Mars bias in its mission selection.

Once, in previous career, I was responsible for strategic planning of the product roadmap for a division of a high tech company.   We had to get a new product line out to remain competitive.  At the same time, executive staff of the company was cutting our division’s budget.  The engineering managers planned one set of products for the first budget, and then another for the first budget cut, and one for each subsequent budget cut.  Thanks to the extraordinary effort of the engineers, each plan made creative use of the expected resources to maximize the resources available with each budget. 

Since I started this blog, I have seen NASA’s expected planetary science budget cut again and again.  Each time, NASA’s managers have put together a new roadmap that makes the best use of the new smaller budget. 

When the Discovery program was created, one of the goals was to allow for riskier, more creative missions.  In the first decade, with ten mission starts, a few missions went over budget and one failed outright.  And we had nine brilliant successes.  In the second decade of the program, however, new missions starts have come at a pace of approximately one every five years.  When I was in charge of strategic planning, as budgets were cut, I became more conservative – the risk of failure in the few products possible was too great.

In the press conference announcing the decision for the InSight Mars mission, NASA’s managers stated that the selection of InSight was based on it providing the greatest confidence of a successful mission within the budget cap.  (All three proposals promised great science.)  Using an existing spacecraft design (the Phoenix Mars lander) and with two of three instruments paid for by partner space agencies, InSight was near the budget cap for the Discovery program.  The other two proposed missions, TiME and the CHopper comet mission, required new spacecraft designs and longer flight times, both adding costs. 

I don’t think that a Mars bias is a cause of NASA’s selection of the InSight mission. Rather, I think that the investments in the Mars program enabled a complex mission (as any Mars landing is) within a limited budget.

Perhaps the message in the selection is not that NASA has a bias but that the Discovery budget cap of $425M is too small to allow for compelling missions to other destinations.  If this is true, the proposal to raise the cap to $500M in the Decadal Survey report may enable new targets for the Discovery program.  However, if new Discovery missions remain twice in a decade events, then I think the natural tendency will be to be conservative with mission selections.  (See this article from Nature or this blog entry for more on the debate on whether Discovery mission selections have become more conservative.)

To enable a well-balanced program of missions to many solar system destinations, NASA’s needs increased fiscal support from the President’s office and Congress.  Instead, the immediate prospect is for possible further cuts as part of sweeping automatic cuts to the federal budget.  (See this blog post atthe Planetary Society’s webpage for the full gory details.) 

Whatever happens, I am confident that NASA’s planetary managers will continue to make best use of the funding made available.  To have the kind of program that I and I think most of my readers would like to see, NASA needs additional funding for planetary research.  NASA’s managers cannot lobby Congress for additional funding.  If you are an American citizen, however, you can.  I encourage you to contact Congress on your own or to join with the PlanetarySociety in its efforts to gain increases in NASA’s planetary exploration budget.

Sunday, September 2, 2012

Organics and ExoMars

The ExoMars Entry, Descent, and Landing Demonstator Module.  Credit and Copyright ESA.

This week’s Science journal included an article on the challenges facing the Curiosity rover in its hunt for organic molecules on Mars.  (Unfortunately, the article is available by subscription only.)  Complex organic molecules would be a clue that Mars may have once harbored life or at least the conditions that allowed for complex pre-biotic chemistry to occur.  Three spacecraft, the two Viking landers and the Phoenix lander, have so far tested Martian soil for organic molecules and come up with negative results.  (Although some argue that the natures of the failures suggest instrument limitations rather than the lack of complex organics.)  The failure to find organic molecules suggests that processes on Mars are destroying organic molecules since the surface is subject to a steady rain of meteorites that contain less complex organic molecules.  Per the article, researchers have identified three mechanisms that may be destroying organic molecules at and near the surface of Mars: oxidizers in the soil including the perchlorate salts found by Phoenix, ultraviolet radiation, and cosmic rays.  The article states, “With decomposed perchlorates, cosmic rays, and ultraviolet radiation ganging up on Martian organic matter, Curiosity's chances of finding it when it scoops up its first soil samples are looking slim. And ‘if we find [soil] organics, it almost certainly will have nothing to do with life,’ says astrobiologist Christopher McKay of NASA Ames. The most likely organics in soils would be those of cosmic dust because they are continually resupplied, so detecting organics is not detecting life,’ he says.”

One of the challenges facing Curiosity’s hunt for organic molecules is that its drill can sample only 10 centimeters into a rock or into the regolith, not deep enough to avoid the agents that destroy organic molecules.  ESA’s ExoMars rover has been designed to sample up to two meters beneath the surface, below the reach of surface destroyers of organic molecules.

ESA has continued to redesign the ExoMars mission with Russia as its only partner after the U.S. declined to participate.  European financing for the total bill remains a challenge and the final resolution isn’t expected until this Fall.

ESA recently published a newsletter on the current state of the mission definition.  The 2016 Orbiter will carry two European instruments – the NOMAD spectrometer to map trace gases and a high resolution stereo color camera.  Russia will supply two additional instruments for the orbiter – the Atmospheric Chemistry Suite that will map the structure of the atmosphere (the ESA publication doesn’t discuss why a chemistry instrument will map structure, which typically is measured in terms of temperature and pressure) and a neutron detection instrument to refine measurements of near surface water ice.

A major goal of the 2016 mission has been to test European technologies for landing mid-sized payloads such as geophysical stations.  (The seven minutes of terror to get a payload to the surface of Mars exists for any space agency wanting to land on Mars.  Developing and proving a landing capability enables future lower cost missions, much as the demonstration of the Phoenix system enabled the recent selection of the InSight mission.)  At one time, there was discussion of including a Russian radioisotope power supply to enable a long-lived lander.  Now the plan has reverted to a battery powered lander with a short (few days at most) lifetime.  

Russia will also supply two new instruments for the 2018 rover mission – an infrared spectrometer and a neutron spectrometer.  (Russia also supplied a neutron spectrometer for NASA’s Curiosity rover to search for near surface hydrogen deposits that would indicate the presence of H2O.)

The brief newsletter also talks about a surface science platform in addition to the ExoMars rover.  It’s unclear what this might be, although a geophysical station might be a possibility.  The supporting web site simply says, “the two space agencies have agreed to send a large capsule to Mars with a surface science platform and a rover carrying both European and Russian instruments. The two science stations will operate in parallel.”  (At one time, before the first descope to reduce costs, the ExoMars mission included a sophisticated geophysical station in addition to the rover.)

Russia will have the leading role in delivering the rover and science station to the surface: “the descent and surface modules will be developed by Roscosmos in cooperation with ESA.” 

Editorial Thoughts: First, I hope that enlightened selection of sampling locations (with maybe a large helping of luck) will enable the Curiosity rover to find the organic molecules its instrument suite is designed to find.  A success would enhance chances for funding a robust future Mars program, while a fourth strike won’t be helpful.

Given the challenges of finding intact organic molecules – assuming they exist – I remain a fan of the ExoMars rover mission and hope it secures it European funding this fall.  I am concerned about the 2018 landing mission becoming too complex – ESA has never done a rover mission and Russia has never successfully landed a mission on Mars.  Now the mission has become more complex with a surface science station.  NASA hit a home run with the Curiosity landing and subsequent rover operations, but that was after a string of six successful, and simpler, landings.  ESA’s track record for planetary missions has been excellent, providing confidence for the ESA 2016 orbiter and 2018 rover.  Russia, after the failure of the Phobus-GRUNT mission last year, reportedly is in the process of reforming its design processes.  Landing a good-sized rover and surface station on your first try at a Martian landing in over 40 years is an ambitious goal.  (A recent article in the Guardian makes the same point, but less diplomatically.  Until I hear otherwise, I presume that ESA and RSA are aware of the challenges and taking appropriate steps.)

My fingers are crossed that the budgetary and technical stars align for ExoMars.  The search for signs of pre- or actual biotic organics on the second most Earth-like planet in the solar system is important to the future of planetary exploration.