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    arstechnica.com

    Scientists are ready, what about you?

    by KUNIO M. SAYANAGI MARCH 14, 2011

    On Monday March 7th, NASA and NSF received the results of the Planetary Science Decadal Survey, whichrecommended planetary exploration priorities to NASA and the NSF for the 2013-2022 decade. The

    highlights of the recommendations are, in order of priority, to (1) collect rocks on Mars; (2) study Europa

    from Orbit; and (3) orbit Uranus and drop an atmospheric entry probe. I was a member of the Giant Planets

    Panel, and had an inside view of the Survey's creation; what follows is both an overview of the results, and a

    look at the process that created them.

    The survey's final results were announced by Cornell's Steve Squyres, who chaired the study. They come in

    the form of a 400+ page document that reviews the state of planetary science today and spells out what

    should come next. The final report is still undergoing editorial corrections, but a copy is already available for

    free on the National Academies Press website.

    Squyres' description of the final report revolved around NASA's three classes of planetary missions. Flagship

    missions are the biggest projects and usually take multiple decades from start to finish. New Frontiers are the

    "medium" class missions, and each costs about one billion dollars and takes less than a decade to complete.

    Discovery program supports "small" missions that scientists directly manage at their home institution. The

    goal of the decadal survey is to set recommendations on all of these research activities, along with

    ground-based observations.

    The recommendations for the Flagship missions are a big deal because their impacts will be felt for decades

    in the future. For example, the current Cassini mission received a green light in 1988, and it took 16 yearsfrom there to arrive at its destinationCassini has been in operation at Saturn since late 2004. These

    recommendations are also a big deal because progresses in planetary science is spearheaded by these large

    missions, so carefully crafting a coherent, long-term strategic plan is crucial to staying on track.

    The survey's single most important goal was to examine the progresses in planetary science over the last

    decade, and to come up with a consensus plan that will lead to new breakthroughs. The survey looked at the

    scientific and technological state of planetary science today; as scientists, the message we are delivering with

    the survey is simple: we are ready to do these missions.

    However, the recommendations come at a tough economic time, and their implementation will depend onwhether NASA receives a budget that allows it to afford those plans. Squyres, who are known for his

    energetic, engaging presentation style, did not hide the uncertain future facing planetary science. Congress

    has not passed the Fiscal Year 2011 budget, and, if the FY2012 budget proposal just announced is

    representative of what NASA will actually receive for the subsequent years, there is a strong possibility that

    we will not be able to fly even one of the priority missions.

    Community consensus

    The recommendations reflect the consensus view of planetary scientists about where we want to go next. The

    survey is conducted by a team of scientists and engineers selected by the National Research Council, which isone of the four divisions of the National Academies (the other three are the National Academy of Science,

    National Academy of Engineering, and Institute of Medicine).

    The survey was divided into five sub-disciplines. The Inner Planets Panel dealt with Mercury, Venus, and

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    Earth's Moon; Mars had a panel of its own. The Giant Planets Panel covered the four outer planets: Jupiter,

    Saturn, Uranus and Neptune, while the Satellites Panel looked at the numerous moons of the outer planets.

    All the other smaller bodies that orbit around the sun, such as the asteroids, comets, and Kuiper belt objects

    were covered by the Primitive Bodies Panel.

    We started working on the survey in the summer of 2009, and the first step was to gather input from the

    entire planetary science community, which came in the form of white papers. In the end, we received 199

    papers with a total of 1669 authors. As of October 2010, Planetary Science Division of the American

    Astronomy Society had about 1415 members, so the survey gathered voices from a majority of planetary

    scientists in the US and abroad. It was an extremely active process and many of us participated in multiple

    white papersI was an author on six of them. The white papers spelled out the scientific priorities, requisite

    technological developments, and mission plans to be considered by the survey.

    Each of these five disciplines had equal weight in crafting the final recommendations, and contributed a

    chapter for the final report, which underwent rigorous peer review. The chapters were compiled into a single

    document with a unified introduction and final recommendations by the Steering Committee, which oversaw

    the entire survey process.

    In writing the report, we were handed common Crosscutting Themes to maintain coherence across the five

    panels, and were asked to focus on scientific questions that address the origin and formation of solar system,

    the processes presently acting to maintain it in its current state, and conditions that support life.

    Big missions, more rovers

    For the Flagship class, the top priority identified by the survey is the Mars Astrobiology Explorer-Cacher, or

    MAX-C. MAX-C is the first of the three missions that will eventually bring rock samples from Mars back to

    Earth. The plan is for MAX-C to collect samples and store them in a special long-term cache box. The second

    step in the proposal is called the Mars Sample Return-Lander, which will lift the samples collected by MAX-Cinto orbit around Mars. Then, the third mission, Mars Sample Return Orbiter, will finally bring the rocks

    back to Earth. The recommendation for the next decade is to execute MAX-C only, with the rest of the

    sample-return campaign to be carried out in the subsequent decades.

    This mission to Mars is a continuation of NASA's Mars exploration strategy that got kickstarted by the last

    decadal survey. That recommended, among other things, the Mars Science Laboratory and MAVEN as

    lead-off missions that will open way for a Mars Sample Return campaignMSL is on schedule to be launched

    later this year, and MAVEN, which will study the Martian atmosphere, in 2013.

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    Mars exploration today and future plans.

    NASA Planetary Science Division.

    In the current design, MAX-C is a six-wheeled rover with about the same size as Spirit and Opportunity. The

    plan considered by the survey will launch MAX-C with another rover provided by the ESA called the ExoMars

    Rover in 2018, and land them together in one shot using the Sky-Crane landing system originally developed

    for the MSL.

    As the name suggests, MAX-C is a mission to search for signs of life on Mars. Past missions' objectives

    focused on the environmental conditions and whether they were friendly to life, but we now have a lot of

    evidence that Mars could have harbored life in the past, if it does not today. So, the MAX-C mission will now

    search for direct evidence of living organisms. The ESA's ExoMars has a similar mission, but it is designed to

    analyze the samples on board without bringing them back to Earth.

    Waiting for a new start

    The second priority, the Jupiter Europa Orbiter, also has an astrobiology emphasisit will employ

    ice-penetrating radar to peer through the moon's surface ice and measure its thickness. There is now a strong

    evidence that the moon has a deep saline ocean underneath the surface ice, which may harbor living

    organisms.

    This mission concept has a long history, which has already been covered in depth. It was recommended as

    the single highest Flagship priority by the last decadal survey, and NASA and ESA made an agreement two

    years ago to work together to develop a joint mission. The plan calls for NASA and ESA to separately send

    their respective orbiters to Europa and Ganymede, two of the four Galilean satellites, (planet-sized moons of

    Jupiter). The joint mission is now called the Europa Jupiter System Mission. Since then, the mission plans

    have been made more specific, and meetings and workshops have been held to help scientists develop

    instruments to be carried onboard for both the NASA and ESA orbiters.

    However, the mission has not been started to datepast large missions to the outer planets, such as the

    Voyagers, Galileo, and Cassini, were funded through a special line of budget specifically passed by Congress.

    The creation of a new budget line is called a new startbut a new start for JEO has not happened to date, so

    the mission concept, which is basically ready to be implemented, has come back before the decadal survey

    again. The survey's recommendation confirms that a mission to Europa remains one of the top priorities in

    planetary science, and makes it clear that the mission is waiting for a new start to be passed by Congress.

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    Artist's conception of the joint NASA-ESA Europa Jupiter System Mission.

    NASA/ESA.

    Let's probe Uranus

    The third Flagship priority is to send an orbiter to fly around Uranus and drop an atmospheric entry probe to

    study its atmosphere in-situ. In contrast to the first two priorities, this is a brand new recommendation

    coming out of the decadal survey.

    The four outer planets can be categorized into two broad groupsthe first contains Jupiter and Saturn, which

    are commonly called the gas giants because they are made up mostly of hydrogen and helium gas. In

    contrast, the two outer-most planets Uranus and Neptune, have considerable amounts of condensable

    chemical elements that can freeze to form ices of water, methane and ammonia, so they are categorized as ice

    giants.

    The only mission to visit Uranus and Neptune to date is Voyager 2, which made brief fly-by measurements of

    the planets in 1986 and 1989. Jupiter and Saturn have since been studied in detail by orbiting spacecraft

    Galileo for Jupiter and Cassini for Saturnso the decadal survey is now recommending an orbiter for the

    next one out, Uranus.

    The study of ice giants have gained a renewed importance in recent years because they appear frequently in

    the list of hundreds of new planets being discovered around other stars. As of this writing, 536 planets

    outside our solar system have been detected, and a majority of them exhibit chemical and physical

    characteristics that suggest that they are ice giants. So, studying the local ice giants in our solar system will

    offer us an insight on what many planets outside our solar system are like. Also, the unique chemical

    compositions of Uranus and Neptune are keys to deciphering the formation of the solar system, which will

    also tell us something about the origin of these other worlds.

    Uranus Orbiter and Probe Concept.

    Ice Giants Mission Decadal Study Report, NASA.

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    Descope, descope, descope

    The decadal report also looks at the mission plans as submitted to the survey, and employed Aerospace

    Corporation to come up with independent assessments of the cost and risks associated with these missions

    -this process is called Cost and Technical Evaluation, or CATE. Even for those of us who are used to looking

    at big numbers, the estimates for the Flagship missions induced extreme sticker shock. MAX-C came out to

    be $4.0 billion, JEO is likely to cost $4.7 billion, and Uranus Orbiter & Probe is estimated at $2.7 billion.

    The survey recommends that MAX-C and JEO must be scaled back so that their costs come down below $2.5

    billion, which would require significant redesigns of both missions. This would be done mostly by removing

    some of the mission goals from the scope of the project, or, descoping. The primary basis for the $2.5 billion

    target is the balance between different programs within planetary scienceNASA simply cannot afford to

    spend that much money on any single target. In any event, even if a descoped JEO can be done in less than

    $2.5B, its implementation will still require a congressional new start.

    The budget projections included in the survey report makes the situation clearthe solid line is the total

    budget projection for NASA's Planetary Science Divisionmost of the things fit below the line, except for the

    light-blue item, which represents the cost for a descoped JEO. MAX-C draws its funding from the existingMars Exploration Program and does not require a new start. In his presentation, Squyres further noted that

    this projection is already oldthe new budget proposal for FY2012 recently submitted by President Obama

    on February 14th include sharp cuts in the funding for NASA, so the situation now is a lot worse than what's

    shown in this figure.

    The budget outlook used in the survey process, based on the numbers for Fiscal Year 2011 proposal providedduring the survey.

    Decadal Survey Pre-Publication Copy.

    So, what's next?

    For MAX-C, the report mentions that one obvious way to bring down the cost is to deliver only one rover to

    mars in 2018; however, as the MAX-C/ExoMars mission is an agreed plan between NASA and ESA, removing

    either of the rovers must involve re-working the agreement. Squyres mentioned in his presentation that

    NASA and ESA already have a meeting scheduled in April, where the discussion is expected to focus on

    reworking their agreements.

    Squyres also urged the JEO team to immediately start looking for ways to make the mission smaller without

    sacrificing too much scienceit's that, or none of the science is likely to actually happen. To be sure, the JEO

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    plan considered by the decadal survey was a bloated version of the mission that had been competing against

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