Mars 2020 Instruments – A Plan for Sample Return

Last week, NASA’s managers announced the selection of seven instruments for its 2020 Mars rover from a pool of 58 proposals submitted by teams of scientists.  Reading through the capabilities of the instruments makes them seem like technology from science fiction, complete with lasers and x-rays.  However, the types of instruments that weren’t selected say almost as much about the goals and expectations for the mission as those that were.  This mission will be optimized for finding the best samples to return to Earth rather than carrying out the most sophisticated science that could have been sent to Mars.

The Mars 2020 rover will be based on the design of the Curiosity rover but will have a new instrument suite and hardware for collecting and caching samples for possible return to Earth.  Credit: NASA

For Mars, the key questions are about the earliest environments present on Mars, whether they could have enabled the development of life, and whether life or its precursors arose.  Answering these questions can require devilishly subtle measurements.  On Earth with the best instruments available (far, far more capable than those that could be flown to another planet), concrete answers are hard to come by and debates rage about the earliest conditions on Earth.  (It doesn’t help that the active surface of the Earth has erased all but a few traces of the earliest surface, atmosphere, and ocean.)

The Mars scientific community has collectively decided that the best and perhaps only way to answer these questions is to return carefully collected samples to Earth for study in terrestrial laboratories.  The primary goal the science community laid out for the 2020 rover was to enable the efficient selection of the most compelling sample set possible – so compelling that Congress will spend the additional few billions of dollars for missions to retrieve and return them to Earth.

Placement of the just announced instruments on the 2020 rover.  Credit: NASA

To see how the instruments selected will work together towards this goal, imagine that you were sent to Mars and given the assignment to select a small set of samples to return to Earth.  Because you can return only a few samples, you are under pressure to find those few special samples that can best reveal insights into the earliest history of Mars.

The first thing you are likely to do is to look to see what types of terrain and rock formations surround you.  The 2020 rover will carry two Mastcam-Z cameras for this task.  These cameras were originally intended to fly on the Curiosity rover currently on Mars, but weren't completed in time.  Unlike Curiosity’s cameras, these will have the ability to zoom from wide angle to moderate zoom (28 mm to 100 mm, 35 mm film equivalent) and to take movies.  (If still photos from Mars are cool, imagine movies.)  These cameras will take color images, but unlike our eyes they will also be able to take images in twelve carefully selected bands (“colors”) in the visible and near infrared spectrum to help map subtle distinctions in composition. 

The 2020 rover also will have the ability to assess the area around it in ways that our eyes never could.  Like the Curiosity rover, the 2020 rover will zap rocks and soils with a laser to determine their composition.  Curiosity’s ChemCam laser heats its targets sufficiently that a tiny amount vaporizes.  The instrument analyzes the glow of the plasma cloud to measure the elements present. 

However, if the laser hits a target with specific wavelengths of light at a lower energy, the target will “glow” in characteristic ways that reveal the mineralogy and the presence of organic molecules. (In technical terms, these are Raman and time-resolved fluorescence spectroscopy.) 

(An analogy helps explain the difference between elemental and mineralogical composition.  French bread, Indian naan flat bread, and tortillas, for example, have similar ingredients (they are much more similar to each other than to, say, a steak or a Greek salad).  In this analogy, the ingredients in the recipes are the elemental composition, while the specific type of baked good reflecting both the proportion of ingredients and method of cooking is the mineralogy.)

The 2020 rover will carry an advanced version of ChemCam called SuperCam that will use all three types of laser analysis to provide both elemental and mineralogical analysis.  In addition, it will have capabilities for mapping composition using visible and infrared spectroscopy, although no details were provided (such as whether this capability will be just for the spots targeted by the lasers or will be full images of the scenes around the rover).

The rocks and formations that Mastcam-Z and SuperCam can study, however, are only those at the surface.  Geological formations often continue beneath the surface and the rocky outcrop in front of the rover may be the same or different than the outcrop viewed a hundred meters earlier in the rover’s drive.  A Norwegian-supplied ground penetrating radar, RIMFAX, will map soil and rock layers up to a half kilometer below the surface with a resolution of 5 to 20 centimeters.

Artist’s concept of how the RIMFAX surface penetrating radar will study rock formations below the surface.  Credit: NASA

To return to our analogy of you as Mars geologist, once you survey a location, you would go to specific soils or rocks that look interesting for closer examination.  Similarly, the 2020 rover will carry two instruments to study small patches (approximately the size of postage stamps) in detail. Both will be contact instruments that operate once the rover’s arm has placed them against a patch of soil or a rock.  (It is likely that the 2020 rover, like NASA’s previous Martian rovers, will be able to brush dust and the outer surface of rocks off to allow instruments to sample the more pristine internal rock.)

The Curiosity rover carried two contact instruments, a microscopic imager and the Alpha Particle X-Ray Spectrometer to measure elemental composition.  The 2020 rover will carry two much more capable contact instruments.  The PIXL instrument will measure elements using X-ray lithochemistry while the SHERLOC instrument will measure minerals using laser Raman and fluorescence spectroscopy.  Both of these instruments will have their own microscopic cameras, and the SHERLOC instrument carry a near copy of Curiosity’s MAHLI microscopic imager.  (MAHLI operates as both a normal camera as well as a microscopic camera.  This camera, mounted on the rover’s arm, has taken the selfie pictures that show the rover on the Martian surface as well as images of the wheels and beneath the rover.)

While Curiosity’s Alpha Particle-X-Ray spectrometer could measure only the average composition of the surface in front of it, both PIXL and SHERLOC will make hundreds to thousands of measurements across each surface.  Each measurement point will be approximately the size of a grain of sand.

An example of how the PIXL instrument will map elements (identified by their chemical symbol in each panel) at a fine resolution across rock surfaces.  The SHERLOC instrument will map mineral and organic composition at similar resolution.  Credit: NASA

The new capability to measure composition at near microscopic resolution will be revolutionary.  If you look at soils and the interiors of most rocks, you’ll find that they are composed of many smaller rocks and inclusions.  By taking many fine-scale measurements, each rock or patch of soil becomes a rich story of many rock fragments that together provide clues to their individual formation and that of their larger rock or soil type.

SuperCam and SHERLOC’s laser spectroscopy will have an important capability that Curiosity lacks – they can easily identify and map the presence of organic materials.  While many processes other than life can produce organic chemicals, life as we understand it requires a rich abundance of organic material.  A key goal for the 2020 rover is to find biosignatures to indicate pre-biotic chemistry or life itself.

The Curiosity rover can detect organic materials through its mass spectrometer, but preparing samples for and using this instrument is a laborious process and has only been done rarely in the mission to date.  In addition, the way the Curiosity’s instrument works, it must heat samples, which triggers chemical reactions with the perchlorates found in the soils, destroying the organic materials.  Careful measurements have allowed scientists to conclude that the samples taken by Curiosity contain some organic materials, but we aren’t sure how much or what types.  (Curiosity’s instrument has a mechanism to avoid the “perchlorate trap,” but it can be used only seven times and hasn’t been so far.)

By using lasers, the 2020 rover can find organics quickly and won’t be skunked by perchlorates, key advantages over Curiosity.

Two other instruments round out the 2020 rover’s manifest.  The MEDA instrument, supplied by Spain, will monitor the weather and study the airborne dust.  MOXIE will demonstrate the extraction of oxygen from the predominantly carbon dioxide atmosphere at Mars.  Missions (manned or unmanned) that are to return to Earth could substantially reduce their launch weight if they could manufacture the oxidizer portion of their rocket fuel form the Martian air.  The same applies to the oxygen supply to breath for any future astronauts.

How does the 2020 rover’s scientific instrument suite (MOXIE is an engineering demonstration) compare to that of the Curiosity rovers?  The 2020 rover will have far superior remote sensing instruments (Mastcam-Z, SuperCam, and RIMFAX) and contact instruments (PIXL and SHERLOC) than Curiosity.  This will allow this new rover to much more quickly find important samples to study and potentially cache.  This is especially true for finding any rich deposits of organic material.

To locate two to three dozen samples within the mission’s lifetime on Mars, the 2020 rover will need to operate much more efficiently than the Curiosity rover has.  The scientific team that defined the requirements that NASA used to select this instrument suite specifically asked for a suite of instruments simpler than Curiosity’s to speed operations.  Because almost a decade has passed since Curiosity’s instruments were selected, the march of technology allows the new rover’s instruments to be considerably more capable than Curiosity’s. 

So what’s left off?  Ignoring the miniature greenhouse and the solar-powered helicopter proposals (either likely would have been media sensations), the 2020 mission will not have the class of laboratory instruments included in the both Curiosity and the ExoMars 2018 payloads.  Performing the most sensitive measurements requires larger instruments than can fit on the robotic arm.  To address this, both the Curiosity and ExoMars rovers have instrument laboratories housed within their bodies.  For example, the Curiosity and ExoMars mass spectrometers can identify the specific composition of organic molecules.  This is useful to separate organics created from non-biotic processes from those created from possible biotic processes.  The laser instruments to be carried by the 2020 rover will be limited to more general identification of the presence of broader groups of organic molecules. 

The mass spectrometer instruments proposed but not selected for the 2020 rover could have been more sensitive still than Curiosity and ExoMars’.  The proposed CODEXinstrument, which would have had to be located as a laboratory instrument within the body of the rover, would have used lasers to vaporize minute quantities of material across the sample to be fed into a mass spectrometer.  (By vaporizing samples, the instrument would have avoided the perchlorate problem.)  The resulting measurements would have provided detailed maps of the chemistry of samples, the types of organics within it, and the age of the rock from which it came.  Achieving both of the latter goals have been two of the justifications for returning samples to Earth.  CODEX would have made progress towards both on Mars, although measurements made in terrestrial laboratories would be much more precise. 

NASA doesn't discuss why particular instruments aren't chosen for a mission.  CODEX and its kin may not have made the cut because the team of scientists that laid down the mission requirements specifically requested a simplified instrument suite.  Or the reviewers may have concluded that the more sensitive measurements would not have been sensitive enough to answer critical questions about Mars.  Or it could be that there wouldn't have been room in the rover or in the budget for them.  The 2020 rover program has a tight budget, and the instrument suite selected will cost $130M, more than the $100M NASA had originally hoped to spend.  (Curiosity’s instruments cost $180M.)

The instruments will be half of the 2020 rover’s payload.  Still to come are details on the sample collection and caching system.  Based on work done to date, it appears that the rover will collect and store two to three dozen sample cores that each will be about as wide as a pencil and about half as long as a new one. 

The 2020 rover will carry an instrument suite optimized for efficiently finding the best sample suite at its landing site for a possible return to Earth.  If those samples do make it to our world, we likely will have a revolution in our understanding of the Red Planet.  If they do not, the scientific community may come to wish they had asked for a more capable instrument complement to do more sophisticated science on Mars.  But life is about choices, and NASA and the scientific community have bet that the samples collected will be so compelling that funds will be made available for their return to Earth.

Either way, the instruments of the 2020 rover will be marvels much more advanced than their counterparts on Curiosity.  We will get great science.

ExoMars 2018 Status

Elizabeth Gibney provides an update on the Mars 2018 mission development at the blog site of the journal Nature.  She reports that schedules are tight, but that managers are working to keep the mission on track for a 2018 launch.  She reports, however, that at least some members of the project team believe a slip to a 2020 launch is a possibility.  Funding for the 2018 mission also is a couple of hundred million Euros short of what is needed, and this will be addressed at a meeting of ESA's governing council in December.

Gibney's report provides more hope that the launch will occur on schedule than does the report on the website RussianSpaceWeb.com that I summarized in a previous post.

Possible Delays for Lunar and Martian Missions

Anatoly Zak, author for the well-respected RussianSpaceWeb.com site, reports on delays for Russia's lunar and Martian missions.

He reports that a three year slip in Russia's lunar missions has been officially announced.  These missions will deliver spacecraft to orbit and land on our moon.  (See this page for a list of the currently planned missions (without launch dates) as well as my earlier post on Russian lunar and planetary plans.)

Zak also reports that the joint European and Russian 2018 ExoMars rover and surface station is facing a likely two year delay to 2020.  A series of delays caused by coordinating the efforts of the two agencies to develop the missions is the apparent cause.  Separately, Europe's portion of the mission's cost reportedly will exceed the currently approved funding limits.  If this occurs, the European Space Agency will need to find and approve additional funds to complete the mission.

The joint 2016 Mars orbiter mission appears to be proceeding well and is expected to launch on time.

Mars and Europa: Contrasts in Mission Planning

The big news for future planetary exploration this month is likely to be the announcement of the instrument selection for NASA’s 2020 Mars rover that will define how it will fulfill its scientific goals.  In the meantime, there have been several announcements for proposed missions to Mars and on the planning for a NASA return to Europa that highlight the contrasts in planning missions for these two high priority destinations. 

China’s chief scientist for its lunar program has stated that China is planning a rover mission to Mars for 2020 and a sample return from that planet by 2030.  The Chinese space program tends to be tight lipped about its plans (especially those still several years out), and I’ve been unable to find any more information.  Is this mission a placeholder on the space agency’s roadmap – much like an eventual Martian sample return for NASA – or an approved and funded program?  Would the rover be delivered by a small lander and therefore be small itself, perhaps like NASA’s 1996 Sojourner rover?  Or perhaps it would be a medium sized rover like China’s Yutu lunar rover and NASA’s Opportunity rover.  Given China’s string of successes and careful build up to more complex missions, if a Martian rover is firmly in their plans, they seem likely to succeed. 

A Chinese rover would find itself part of a crowd on the Martian surface in 2020.  As mentioned above, NASA plans its own Curiosity-class rover for that year.  Europe’s ExoMars rover is likely to still be operating along with its Russian stationary lander.  I’m willing to bet that NASA’s 2016 InSight lander and Curiosity rover will still be functioning, and I have some hope that the Energizer bunny-Opportunity rover will still be alive (although perhaps as a stationary platform by then).

Mars exploration has reached the point where private organizations can promote credible plans for complex Mars missions on the web.  Credit: BodlyGo Institute and Mars One

If two private organizations have their way, the party at Mars will be more raucous still.  The BoldlyGo Institute would like to raise funds for its SCIM spacecraft that would dip briefly into the upper atmosphere during a high speed flyby to snag dust and atmosphere samples to return to Earth.  While we have some 130 rocks delivered as meteorites that are believed to be from Mars, this mission would return samples of the dust that ubiquitously blankets the planet.  If this idea seems familiar, it was proposed twice before in NASA’s Mars Scout and Discovery mission competitions.  Now its backers hope that this mission will have better success at securing private funders.

Another organization, Mars One has been planning to land humans on Mars in about a decade’s time.  Recently, it announced plans for a Martian lander for 2018 built on the same platform as NASA’s Phoenix and InSight landers.  Mars One is seeking proposals for instruments that would be useful to eventually colonization of Mars.  For example, the organization is requesting proposals to demonstrate water extraction from the soil.  It would also deliver one instrument developed by a university to the surface of Mars.

Both of these missions depend on finding funding from some combination of rich donors, corporate sponsors, and crowd sourcing from small donors. I’m never quite certain how much hope to hold out for missions that depend on private donations.  Given their scope, these two missions would likely costs of several hundred million dollars; each mission would either need a fantastic number of small contributors or one or more wealthy contributors.  While rich space enthusiasts exist (I’m thinking of  Elon Musk of SpaceX as an example), if you are very, very rich and have the slightest inkling towards philanthropy, then fund raisers from many worthy causes from universities to global health to saving species are already in touch with you. 

Rather than dividing potential support, having multiple organizations trying to raise funds may benefit private planetary exploration.  We can’t know beforehand which, if any, approaches will open check books and competition may help us learn what will work.  (The B612 Foundation is another player looking to finance a challenging mission, in their case a space telescope to search for near Earth asteroids.)

Jeff Foust at The Space Review had a story recently on the potential for private funding of space missions.   While raising hundreds of millions of dollars my prove too daunting, technology is on the cusp of enabling small planetary spacecraft based on CubeSat and SmallSat technologies that would cost just a few tens of millions of dollars.  The Planetary Society’s LightSail project is an example of such a mission (although it will test critical hardware in Earth orbit rather than fly to another world).

If planning for Mars missions is becoming commonplace, NASA is still trying to find a plan to for a dedicated mission to Europa.  In a step forward, the agency has released a request for proposals to the scientific community for instruments for a Europa mission.  It did so, however, in a rather odd fashion.

Reddish features in this colorized image of Europa's surface likely contain  water ice mixed with hydrated salts, potentially magnesium sulfate or sulfuric acid that may represent material from the interior ocean.  Full caption available at http://www.nasa.gov/content/reddish-bands-on-europa/. Credit: NASA/JPL-Caltech/SETI Institute

Usually when NASA requests instrument proposals, it has a solid mission concept in mind.   For this call, NASA said that the Europa mission might be an orbiter or might be a multi-flyby spacecraft.  The request document was vague as to the budget for instruments and just said that past studies assumed it would likely be around 15% of the total mission cost.  While many instruments by their nature have modest costs, some could be quite costly and it might help proposers to know whether the total instrument budget is closer to $150M (for the $1B total mission cost NASA would like) or to $300M (for the ~$2B that past studies have said is needed to achieve all the high priority scientific goals).

For some instruments, proposers will have to bet that NASA either selects a multi-flyby spacecraft or an orbiter.  For example, measuring Europan tides would help pin down the depth of the ice covering the ocean.  A laser altimeter could accurately measure the tides, but it requires an orbiting platform to pin down the size of the tides.  If NASA goes with a flyby spacecraft, any group that proposed an altimeter is likely to be out of luck.

Examples of instruments that the scientific community may propose to study Europa.  From the Europa instrument Announcement of Opportunity available here.

The request for proposals gives two roadmaps for how NASA will select the winning proposals.  Its managers expect that they will select up to 20 proposals in April 2015 for which they will fund further development towards a final selection of approximately eight instruments a year later.  NASA also reserves the right to simply select the final instrument suite in April 2015.  The document implies that the longer timeline assumes a launch no earlier than 2021, while the shorter timeline could either reflect a possible earlier launch date or the possibility that the proposals seem ready for selection without an additional year of maturation. 

With this request, NASA appears to be showing its commitment to an eventual Europa mission, but it still hopes to find a cheaper alternative that will win the allegiance of the scientific community.  The large cost overruns on the Curiosity Mars rover and James Webb Space Telescope have made the White House’s budget managers and NASA’s senior managers wary of multi-billion dollar missions. 

SpacePolitics.com reports that NASA has received a number of concepts for Europa missions that might cost no more than $1B.  The agency is currently assessing these ideas for their cost, technical, and scientific feasibility.  Comments by NASA’s chief scientist suggest that these missions likely would perform only a fraction of the science considered high priority by the scientific community (and that would be accomplished by the current ~$2B mission concept).

In the request for instrument proposals, NASA specifically asked for instruments that could study possible plumes of water erupting from Europa.  The recent possible discovery of plumes at Europa has raised the question of whether and how planning to explore this world should be changed.  If the plumes are verified, then they represent a chance to directly study material being ejected into space from beneath Europa’s surface as Cassini has been able to do for Saturn’s moon Enceladus. 

The request comes despite the recommendations a few weeks earlier of NASA’s Europa Science Definition Team.  They reviewed both the evidence for Europan plumes and the experience studying plumes erupting from Saturn’s moon Enceladus with the Cassini spacecraft.  Their recommendation was that a mission to Europa should be capable of exploring plumes if they exist, but that a dedicated focus on the plumes would not be appropriate. 

First of all, the team noted, only one observation made by the Hubble Space Telescope saw possible plumes.  Other searches for plumes by telescopes and by the Galileo spacecraft when it orbited Jupiter have not found unambiguous evidence for plumes.  (Some Galileo data is consistent with plumes but also have other possible explanations.)  Even if the Hubble did observe one or more plumes, they may occur at sporadic intervals separated by years or decades.  If so, they would be more like the sporadic eruptions of each volcano on Io than the so-far continuous eruptions seen at Saturn’s Enceladus.  A mission to Europa lasting a few years might entirely miss plumes if they sporadically erupt.

Second, Cassini’s observations of Enceladus’ plumes have shown the power of a diverse instrument set to characterize plumes.  Instruments already recommended for the ~$2B Europa mission concept could be used to search for and study any plumes.  A mass spectrometer, for example, could determine the composition of the gases expelled from the surface, while the thermal imager could look for warm spots that would be the source of the plumes.  A couple of instruments such as a UV spectrometer and a dust spectrometer that haven’t made the straw man list of instruments used for mission studies to date would enhance plume studies, but these instruments also would be useful for studying the rest of Europa.

The instrument request document acknowledges the science team’s assessment, but states that, “the scientific potential presented by the plumes is sufficiently high that NASA will continue to emphasize the importance of plume investigations and encourages instrument investigations focused on this area.”

Draft summary of findings by the Europa Science Definition Team regarding possible Europa plumes and planning for a mission to that moon.  Entire presentation available here.

While NASA’s management decides the scope of a Europa mission, engineers at JPL continue to refine the design of the current leading concept, the Europa Clipper that comes with an estimated cost of $2.1B.  The current concept would have the Clipper spacecraft make 45 dashes through the radiation fields surrounding Europa for close up looks at the surface and interior.  Building a spacecraft and instruments that can survive that radiation exposure is one of the factors that has driven the cost well above the $1B NASA’s senior managers would like to see.

A presentation made to the science team also provides more insight as to why a large number of encounters are required to study Europa.  The science team has carefully justified what measurements are needed at Europa to understand this world and to enable planning for a lander that would follow the Europa Clipper. 

As an example, the science team has stated a requirement that the composition of 70% of the surface be mapped at resolutions of  less than 10 kilometers by an instrument known as a short-wave infrared spectrometer.  With 45 encounters, this goal would be just missed with 68% of the surface mapped.  (Thirty flybys would map 50% at this resolution or better.)  Similarly, mapping 70% of the surface with an imaging camera at resolutions of 1 kilometer or better would require 38 flybys.  A global distribution of flybys to study the structure of the ice and ocean beneath the surface with an ice penetrating radar would not be met until 43 flybys. 

If the radiation belt did not exist, the next stage to exploring Europa would be to orbit it instead of frantically gathering data during numerous brief flybys.  (Europe, for example, will send the JUICE spacecraft to orbit Europa’s sister moon Ganymede, but that moon lies outside the harshest portions of the radiation belt.)  JPL’s studies suggest that a Europa orbiter would cost about the same as the Europa Clipper, but its lifetime would be so short that the Clipper with its many flybys would better study this moon.

We are left with contrasting opportunities for studying these two worlds.  Mars is close enough and benign enough that both China and private organizations can seriously consider challenging missions.  Europa’s location within harsh radiation belts leaves it as both a technical and a budget challenge.

Congress Weighs in on NASA 2015 Planetary Budget

The two houses of Congress have written their proposed 2015 budgets for NASA.  The House bill would add additional funding to almost every category of the Planetary Science budget and would greatly strengthen NASA’s program of planetary exploration.  The Senate bill would add substantial funds to the Mars program but pay for this by cuts to other portions of the planetary budget. 

In American politics, the President proposes federal budgets but it is Congress that decides federal budgets.  Last winter, the President’s budget office proposed a Fiscal Year 2015 planetary budget that was better than proposals for previous years but still well below the levels needed to enact the program laid out by the science community in the Decadal Survey.  Both houses of Congress have now proposed their alternative plans (although the Senate budget has not been approved by the entire body yet).  How has planetary exploration faired? 

It’s useful to start by looking at their changes to NASA’s entire science program.  Each of the science divisions – planetary, astrophysics, heliophysics, and Earth – are operating on budgets well below what’s needed to fulfill the visions in their Decadal Surveys.  However, the political parties have settled on a budget compromise that sets a limit on overall government spending.  Within that limit, the Congressional bills have been fairly generous in proposing increases for NASA’s science programs in lieu of spending on other government programs.  Both Congressional bills would increase funding for astrophysics, but the House favors a substantial increase for planetary exploration while the Senate proposes a modest increase for Earth science (most of which is simply the transfer of satellite programs and their funding from another government agency). 

Changes proposed to the President’s budget for NASA’s science programs.  Credit: V.R. Kane

Within the proposed budget for Planetary Science, both bills propose to increase funding to the Discovery program to enable these small missions to be flown more frequently.  The bills differ substantially though in whether they favor a substantial increase to the Mars program (the Senate) or for defining a Europa mission through increased Outer Planets funding (the House) and to the research and analysis and technology development programs (the House).  Both bills appear to provide funding sufficient to operate all missions already in flight, reversing the proposal in the President’s budget to shut down the Mars Opportunity rover and the Lunar Reconnaissance orbiter.  (The Senate bill does not directly address the latter but does appear to provide sufficient funds for the orbiter.)

Changes proposed to NASA’s Planetary Science Division budgets.  Credit: V.R.Kane

Both the House and the Senate bills propose to increase spending for the Mars program.  The House bill would add $22.7M, a bit more than is needed to continue operating the Opportunity rover as well as all other Mars missions in progress and continue the development of the 2020 Mars rover.  The Senate bill would be much more generous with an increase of $65.7M.  The Senate bill specifically states that it wants to see all current Mars missions continue operating (which would require approximately $15M over the President’s request) but does not specify what the remainder of the funding would go towards.  NASA could use the remaining increase for development of the 2020 Mars rover, which is on a tight budget.

Both the House and the Senate bills would provide increased funding for the Discovery program with the increase targeted to enabling selection of the 14^th mission in the series to occur in approximately two years.  (The 12^th missions, the Mars InSight geophysical rover is in development and is fully funded, and the selection process for the 13^th mission is in progress.)  Both Congressional bills direct that Discovery missions are to be selected every two years in accordance with the recommendations of the Decadal Survey rather than the every five years of the past decade.

If the Discovery program receives funding in future years’ budgets for missions every two years, or five per decade, this is a tremendous boost to NASA’s program. 

Both Congressional bills state the importance of a mission to globally explore Europa, but take very different directions with recommended funding levels.  The House bill would add $85.3M to the Outer Planets budget, which on top of the President’s request would provide $100M to continue preparatory design for the mission.  The House bill directs NASA not to consider any Europa mission that would be substantially cheaper than the ~$2B Europa Clipper it is currently defining.  This is in response to the request of the President’s budget office and NASA senior management seeking ideas for a mission that would cost approximately half as much.  The House bill states that the committee that drafted its bill has not seen any “credible evidence” that a scientifically useful mission could be flown for $1B.

The Senate bill cuts the Outer Planets program by $16.7M, or a little more than $15M the President requested for Europa studies.  (The remaining funds would support the Cassini mission at Saturn and pay for development of US instruments on the European JUICE Jupiter-Ganymede mission.)  The Senate bill gives no explanation for the cut.  In fact, it states in the text that it support’s the President’s funding levels for the Planetary Science program except for increases the Discovery and Mars programs.  The cut to the Outer Planets funding appears in a table, but no explanation is given.

The Senate bill directs NASA to plan to use the Space Launch System (SLS) booster to launch a Europa mission, while the House directs NASA to consider using the booster.  The SLS has the ability to deliver a Europa mission to Jupiter in around 2.7 years compared to a 6.4 year transit if commercial boosters are used.  However an SLS launch would cost ~$1B compared to a few hundred million dollars for a commercial launch.  Congress plans to fund the development and building of several SLS boosters so their cost is already covered. 

While the House and Senate bills both would increase net spending to develop future missions with one favoring Mars and the other Europa, the Senate bill would cause harm elsewhere.  While the House bill supports small increases to the Planetary Science program’s research and technology programs, the Senate bill would impose significant cuts to these programs.  Cutting the research program likely would reduce grants to scientists.  At best, this would stall work to analyze data returned from NASA’s missions.  At worst, this would force a number of scientists and graduate students who depend on these grants to leave the field.

Eventually, the two bills will be reconciled into a single budget that will set NASA’s funding for current and future missions for 2015.  From my news reading, it’s widely expected that the final reconciliation of the House and Senate budgets won’t occur until late this year following the Congressional elections in early November.