Surface sampling from Titan balloon

Space.com has an article on the possible ESA Titan balloon contribution to a Flagship Titan Saturn System mission http://www.space.com/scienceastronomy/081106-am-titan-balloon.html.

The article states that the balloon gondola will have the ability to float and lakes while the mission will have the ability to grab and then analyze surface samples. This would be great if it's true, but I have my doubts. While it is easy to have a balloon descend to the surface, it is much harder to prevent damage to the gondola and balloon if winds drag them across the surface. Perhaps this is some kind of snake that would be tolerant of dragging across the surface that would be lowered to the surface to grab samples.

These low ground maneuvers would be that much harder to manage with Titan a long distance away (I forget how long it takes a radio wave to travel the distance) and the orbiter only occasionally in direct contact with the balloon (even when the orbiter has reached Titan orbit).

Anyone know anything more about this?

On the bummer side, the TSSM mission would arrive in the Saturn system in 2030. That would make me only 74 on arrive and about 76 when it finally reaches Titan orbit. Whichever flagship destination is chosen (Titan or Europa), this will be my last outer planet flagship mission. I suddenly feel a lot older...

Post MSL Mars Rover

In a previous post, I discussed possible options for NASA Mars missions following the Mars Science Lab (MSL) and the Scout Maven upper atmosphere mission for 2013. In this post, I will discuss current thinking about a follow on rover mission.

There are three explicit goals for a next generation Mars rover:

o Launch within 6 to 8 years of MSL to keep the rover development team intact. This would require a launch by 2016 if MSL holds to its current 2009 launch.
o Explore a new type of Mars terrain that has an apparent history of an aqueous environment and therefore a possible past site of biological activity. The flotilla of Mars orbiters has identified at least 8 types of terrain with aqueous history. Opportunity is exploring one type, MSL will explore another, and hopefully ExoMars will explore a third. A 2016 rover would target yet another.
o Collect and cache a sample suite that could be retrieved by a future sample return mission.

And one implicit goal:

o Fall in price between MER ($820M for two rovers (equivalent to ~$1.2B in 2016 dollars at 3%/year inflation)) and MSL (>$2B). A February 2008 cost estimate for the 2016 mission was $1.6B (although it wasn’t stated whether that was 2008 or 2016 dollars).

The 2016 rover would be larger than the MER rovers (~250kg vs 174kg) with ~11kg of instruments (vs 4.5kg for MER) plus the sample collection and caching system. A precision landing capability would require a landing system similar to MSL’s skycrane. Using solar power would reduce costs compared to MSL nuclear power system. Funding the development of the 2016 is stated to be difficult within projected budgets for that launch opportunity.

The current rover concept looks like MER, probably to emphasize its modest goals compared to MSL (I expect that the final design will be different than both).

A straw man science payload would be an expanded set of MER instruments. An alpha-proton-x-ray spectrometer would identify rock and soil elements. A near infrared (NIR) spectrometer replace’s MER’s mini thermal emission spectrometer (mini-TES) for remote mineral identification. A second NIR would work in conjunction with the microscopic imager for close up mineral identification. A Raman spectrometer would identify minerals, including those bearing carbon molecules. The sample cache system could be able to cache 20 rock cores and 3 regolith samples.

So far, this post has reported on the current thinking presented at Mars Exploration Program Analysis Group (MEPAG) meeting. What follows are my editorial comments. As currently envisioned, the 2016 rover would be a one of a kind mission flown in only one launch opportunity, like MER (but with two rovers) and MSL. I personally disagree with this plan. Designing and testing each rover and entry and landing system is an expensive proposition. Given limited Mars program funds, I think that flying one off mission designs is sub optimal. The Mars program has reused its orbiter designs across multiple missions. So far, though, the apparent reuse of rover design between missions has been much more limited.

In my opinion, the Mars program after 2013 should focus on exploring the diversity of Mars surface terrains. The 2016 opportunity should be used to fly the Mars Science Orbiter (MSO). This orbiter would study trace gases in the Martian atmosphere and continue climate studies. Most importantly for future rover missions, this orbiter could also carry a new high resolution camera to examine landing sites and enable traverse planning as well as act as a communications relay.

The next several Mars launch opportunities would then fly identical copies of the new rover design to study a variety of Martian terrains. This approach amortizes the high cost of the initial design and testing across multiple flights. It also gives us ground truth at multiple sites and ready to retrieve sample caches from a diversity of sites. Landing sites could either be selected by the whole community as done for MER and MSL, or principle investigators could compete with proposals to fly to particular locations.

There are issues with my proposal. The later flight date for the first rover flight creates a long delay after the MSL design (and hopefully its launch) making it hard to keep the design team together. Improvements in technology would make it impractical to refly the same design too many times (although subsystems could be enhanced between launches). Two to four launch opportunities (~4-8 years) seems to be the maximum practical before a redesign to make use of new technologies makes more sense than reusing an existing design. Another issue is that this roadmap has no place for a Mars network mission, which has the second highest science priority after a Mars sample return. One solution would be to fly the network mission in 2018 and delay the rover mission to 2020, although this exacerbates the problem of keeping the rover team intact. Another solution would be for another nation to fly the network stations with NASA providing communications relay with MSO.

I welcome your comments and alternative proposals.

Useful links:

2016 Landed Mission Concepts & Possibilities
http://mepag.jpl.nasa.gov/meeting/sep-08/MEPAG_2016_Rover_V4c.pdf

Mars Architecture Tiger Team (MATT) Presentation Feb 2008
mepag.jpl.nasa.gov/reports/MATT2_final_cleared.pdf

Mars Architecture Tiger Team (MATT) Presentation Aug 2008
http://mepag.jpl.nasa.gov/meeting/sep-08/Christensen_MATT2_for_MEPAG.pdf

Anonymous comments now enabled

I'm still learning the basics of this site and just learned that anonymous commenting had been turned off. It is now turned on.

I've been busy with another project (tricky bug that had to be tracked down) and the election. Once the latter nonsense is over, I'll be back with some more posts.

Notes (from Bruce Moomaw)

(1) The presentations at the June OPFM Instruments Workshop ( http://opfm.jpl.nasa.gov/community/opfminstrumentsworkshoppresentations/ ) are extremely useful.

(2) Mark Perry's presentation ( http://opfm.jpl.nasa.gov/files/1.4_Perry.pdf , pg. 17) points out something I should have caught but didn't: the long dipole antenna for the proposed subsurface radar sounder on the Titan Flagship can only be deployed after the spacecraft has braked into an initial elongated orbit around Titan and then gradually aerobraked into a low orbit around it -- so, it cannot do any subsurface radar sounding of Enceladus during the flybys of that world. However, I see nothing to indicate that the proposed Polymer Mass Spectrometer couldn't analyze gases or light aerosols in Enceladus' plumes -- or, with proper augmentation, larger solid particles in the plumes if they impact a metal target, as with Cassini's current Cosmic Dust Analyzer. (Of course, the high speed of the impacts would tend to break down complex organics into simpler ones.)

(3) Still nothing on the upcoming New Frontiers 3 announcement of opportunity -- but, while looking for it, I discovered that the team that proposed the "OSIRIS" near-Earth carbonaceous asteroid sample return that was a Discovery finalist last time has made the sensible decision to propose a souped-up version of it ("OSIRIS REx") for the upcoming New Frontiers AO ( http://sci2.esa.int/Conferences/MarcoPolo-ws08/The_OSIRIS_mission_-_Dante_Lauretta.pdf ). The nature of the scientific souping-up is undescribed; but there are 7 possible targets, including Wilson-Harrington.

Future flagship missions (from Bruce Moomaw)

I will post e-mails I receive (always with permission) that express well thought out views on future planetary missions and roadmaps. The following comes from Bruce Moomaw on future flagship missions.

[referring the the great new images of Enceladus, Bruce writes:] Let's also not forget that the Titan Flagship mission as it's now designed would include four low-altitude Enceladus flybys (100-200 km) during its Saturn orbiting phase before entering Titan orbit -- and some of its Titan-oriented instruments could provide a surprising amount of new Enceladus information. In particular, note that it includes a subsurface radar sounder and an aerosol-analyzing mass spectrometer with a peak AMU range MUCH higher than Cassini's, allowing a search for really complex organics in the Enceladus plume particles as well as in Titan's upper atmosphere: http://opfm.jpl.nasa.gov/files/1.2_Reh.pdf .

As for whether we should go for the Europa or Titan mission first: damned if I know. But let's remember that -- as the latest Planetary Science Subcommittee report points out ( http://www.lpi.usra.edu/pss/report/nacReportOct2008.pdf , pg. 4) -- whichever one is rejected for this round may well NOT be the SECOND big non-Mars Solar System flaghip mission chosen. In particular, it may have competition for the next round from a Neptune orbiter/probe mission (although it's clear that the so-called "Venus Flagship Mission" now actually consists, probably wisely, of a flock of separate smaller missions that can be flexibly scattered all over the place timewise). In short, whichever mission doesn't get the nod this time around -- whether Europa or Titan -- may not get off the ground for a long, long time.

(As a wild speculation, could this be a very indirect point in favor of picking the Jupiter-Europa Flagship? One important component of the Titan mission -- the Titan lander -- could be flown separately at relatively low cost IN ADDITION TO the Jupiter-Europa Flagship, at about the same time, if it takes the form of a short-lived Titan lake organics-analysis boat dropped off by a flyby craft. After all, that's one of the Stirling-powered Discovery proposals, and it could be flown as a solar-cell-powered mission too. It would also be an ideal opportunity for a NASA-ESA collaboration. By contrast, you can't seem to break off any comparably low-cost chunk of the Europa Flagship mission and fly it separately at about the same time as the Titan Flagship.)