First 2009 MSL Landing Site Workshop Options

[CosmicRocker]

I received this in email today. I haven't even begun to digest it all yet, but it really gives one a sense of the many complexities that must be considered by those who would compete in a game like this. It's kind of long, but I thought some of you would like to see it.

It's also kind of exciting to get a glimpse of the things planned for MSL. Now, I better appreciate some of the stuff the various space mission teams had to consider before they were selected for the end game. This is interesting stuff...

Oh, and just in case anyone thinks I am one of the "colleages" it was addressed to, I'm not. I just managed to land in some address list.

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FIRST ANNOUNCEMENT FIRST ANNOUNCEMENT
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FIRST LANDING SITE WORKSHOP FOR THE
2009 MARS SCIENCE LABORATORY
May 31st-June 2, 2006
Pasadena, CA

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FIRST ANNOUNCEMENT FIRST ANNOUNCEMENT
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Dear Colleagues:

You are invited to participate in the First Landing Site Workshop for the 2009 Mars Science Laboratory (MSL) rover mission to Mars. The workshop will be held May 31 through June 2, 2006, in Pasadena, California.

AN OVERVIEW OF WORKSHOP OBJECTIVES:

The purpose of the Landing Site workshop is to identify and evaluate potential landing sites best suited to achieving stated mission science objectives within the constraints imposed by engineering requirements, planetary protection requirements, and the necessity of ensuring a safe landing. A NASA-appointed Landing Site Steering Committee and the Mars Science Laboratory Project will use the results of the workshop as the basis for narrowing the list of potential landing sites under consideration. Community consensus with respect to high priority sites will also be solicited. In addition, the workshop will provide a means for identifying potential landing sites as targets for imaging by the MGS, Odyssey, MRO, and perhaps other orbital assets. Note: the number of potential landing sites is high because MSL entry, descent, and landing capabilities enable a small landing error ellipse (20 km diameter), high landing site altitude (<2 km), and wide latitudes (±60°).

MISSION SCIENCE OBJECTIVES:

The primary scientific goal of the Mars Science Laboratory (MSL) is to assess the present and past habitability of the martian environments accessed by the mission. Habitability is defined as the potential of an environment to support life, as we know it. Such assessments require integration of a wide variety of chemical, physical, and geological observations. In particular, MSL will assess the biological potential of the regions accessed, characterize their geology and geochemistry at all appropriate spatial scales, investigate planetary processes that influence habitability, including the role of water, and characterize the broad spectrum of surface radiation. To enable these investigations, MSL will carry a diverse payload capable of making environmental measurements, remotely sensing the landscape around the rover, performing in situ analyses of rocks and soils, and acquiring, processing, and ingesting samples of rocks and soils into onboard laboratory instruments. A candidate landing site should contain evidence suggestive of a past or present habitable environment. To the extent that it can be determined with existing data, the geological, chemical, and/or biological evidence for habitability should be expected to be preserved for, accessible to, and interpretable by the MSL investigations.

An overview of the MSL mission can viewed at http://mars.jpl.nasa.gov/msl/overview. A summary of NASA's Mars exploration strategy is at http://mars.jpl.nasa.gov/mep/mslides/index.html and additional information can be viewed at http://mepag.jpl.nasa.gov/reports/index.html. Web tools for visualizing and analyzing relevant Mars data as well as an archive of previously proposed and selected landing sites are available at http://marsoweb.nas.nasa.gov/landingsites/and http://webgis.wr.usgs.gov/, which also includes a web based GIS interface for relevant Mars data. Web sites for MSL landing site selection activities are http://marsoweb.nas.nasa.gov/landingsites/ and the USGS PIGWAD site http://webgis.wr.usgs.gov/msl, where workshop announcements, program, and abstracts can be accessed along with more detailed descriptions of the MSL mission, science objectives and investigations, and instruments.

PLANETARY PROTECTION CONSIDERATIONS:

The MSL project has been assigned to Category IVc by NASA's Planetary Protection Office with constraints on the landing site and regions accessed from it. Specifically, MSL is limited to landing sites not known to have extant water or water-ice within one meter of the surface. Later access to "special regions" defined in NPR 8020.12C (regions where terrestrial organisms are likely to propagate, or interpreted to have a high potential for the existence of extant martian life forms) is permitted only in the vertical direction through use of sterilized sampling hardware. The above are general guidelines for site selection; compliance of specific landing sites and nearby regions will be determined through discussions with the Planetary Protection Office during the site selection process.

MISSION ENGINEERING CONSTRAINTS:

Because the ability to ensure a successful landing for MSL is paramount, consideration of landing sites must include comprehensive assessment of limitations imposed by mission engineering constraints. Although these constraints continue to be established and refined, a description of preliminary values related to allowable locations, elevation, and surface properties follows.

The entry, descent and landing scenario employed by the Mars Science Laboratory (MSL) flight system places engineering constraints on what would be considered a safe landing site of high scientific interest. The dominant considerations in landing site placement are latitude, elevation and the landing ellipse size. The MSL flight system is capable of landing in a circle of 20 km diameter, within which everywhere must be safe for landing and roving. This circle can be placed anywhere on Mars that is below +2 km MOLA elevation and within 60° latitude of the equator (60°N to 60°S). Steady state horizontal and vertical winds and wind gusts are a concern during descent and landing, so areas with potentially high winds will need to be compared with landing system tolerance during development. The landing system uses a radar altimeter, so the entire landing site must be radar reflective. Slopes at long and intermediate (2-5 km and 20 m) wavelength could negatively impact the altimeter, requiring slopes over 2-5 km length scales <3° and slopes over 20 m length scales <15°. Short wavelength slopes affect landing stability and trafficability, requiring slopes over 5 m length scales <15°. Rocks higher than 0.6 m are a problem for landing, requiring areas with intermediate or lower rock abundance. The landing surface must be load bearing and trafficable and so must not be dominated by dust. Persistent cold surface temperatures and CO2 frost will negatively impact performance. These latter three considerations will likely eliminate areas with very low thermal inertia and very high albedo. Surface characteristics (short wavelength slope, rocks and dust) of a trafficable surface are similar to those required for safe landing, except the small landing ellipse and long traverse capability allow the possibility of considering "go to" sites. These sites have a safe landing site adjacent to the target of science interest and require traversing outside of the landing ellipse to sample the materials of highest interest. In this case, the area that must be traversed to get into the region of highest science interest (required to accomplish the science objectives of the mission) must be trafficable from anywhere within the ellipse. All of the values for the parameters discussed will be refined during continuing design and development of the spacecraft, with updates posted on the web site, as will a more detailed discussion of these constraints. We expect the first posting around February 1, 2006 at http://marsoweb.nas.nasa.gov/landingsites/ and the USGS PIGWAD site: http://webgis.wr.usgs.gov/msl

All persons planning to participate in the workshop should review the science, engineering, and planetary protection constraints carefully, as only those landing sites that meet these constraints will be accepted for presentation at the workshop.

HOW TO PARTICIPATE:

All members of the scientific community are encouraged to participate in this important activity. Persons wishing to make a presentation at the workshop are urged to carefully review the science objectives and engineering and planetary protection constraints at http://marsoweb.nas.nasa.gov/landingsites/ and at the USGS PIGWAD web site noted above.

Most of the workshop will be devoted to submitted papers describing: (1) the overall types of sites for MSL based on associated scientific and programmatic rationale and suitability for safe landing and roving; and (2) individual landing sites on Mars and their scientific merit and safety. Individuals must prepare an abstract (no longer than one page using standard LPSC abstract format) summarizing their proposed topic or site. Talks advocating an individual site must summarize the science merits and demonstrate that the proposed location satisfies the mission science, planetary protection, and engineering requirements. A clear statement of the rationale for continued consideration as a possible landing site should also be included. A program will be prepared from the submitted abstracts and will be posted along with logistical information in late April, 2006.

Abstracts (no longer than one page using standard LPSC abstract format) are due by March 28, 2006, and should be submitted electronically via http://marsoweb.nas.nasa.gov/landingsites/. Detailed instructions on abstract format and submission will also be posted at this web site in February, 2006.

LOGISTICS FOR THE WORKSHOP:

The workshop will be held in the vicinity of JPL in Pasadena, CA, and there will not be a registration fee. In order to get a sense of the number of people likely to attend the workshop, interested individuals should indicate their intent to attend via http://marsoweb.nas.nasa.gov/landingsites/ by April 1st, 2006. Although we anticipate mostly oral presentations, there may also be poster sessions. Additional logistical information about the workshop will be distributed to the community in subsequent announcements and will be posted at: http://marsoweb.nas.nasa.gov/landingsites/ and http://webgis.wr.usgs.gov/msl Input from the science community is critical to identification of optimal landing sites for the MSL. We look forward to your involvement in these activities!

Regards,

John Grant Matt Golombek
Co-Chairs, Mars Landing Site Steering Committee

[edstrick]

Hypothetically, you could have inflatable wheels that would be filled with a quick-setting spongy foam during inflation. That way, maintaining pressure during a long mission life wouldn't be critical.

You might have problems maintaining wheel temperature at a reasonable level during foam curing, or coming up with a foam that would cure at suitably low temperatures.

[dvandorn]

Pathfinder's site was quite rocky...

So is the Viking 1 site -- a rather larger overall rock population than at Gusev, and the dominant rock size is larger. The Viking 2 site is rockier still -- in fact, I would say that the Viking 2 site is non-navigable by a rover the size of the MER, and the Viking 1 and Pathfinder sites are semi-navigable.

The one thing I noticed right off was that Gusev isn't as rocky as any of the previous three landing sites. Of course, Meridiani is something quite different from anything we have ever seen on Mars before.

I think the Viking 1 and Pathfinder sites are rocky primarily because they are located in outflow channels, where massive floods deposited a whole lot of rocks as they rolled through. I've never heard a good geological discussion as to why the Viking 2 site is so densely rock-strewn, though -- it's a rather high-latitude northern site, so perhaps the "type 2" plains deposits have simply been broken into a fairly well-sorted carpet of large fragments by frost heaving?

-the other Doug

[MaxSt]

Having a computer then figure out the "best" route to get somewhere requires a whole new level of complex programming. Having it find multiple routes yet, and evaluate multiple factors, such as traversability and distance travelled, and then choose, that too is difficult.

Actually, pathfinding is quite common in modern computer games (shooters). Computer-controlled opponents have to navigate in 3D maps, to "get" you as fast as possible.

[J.J.]

So is the Viking 1 site -- a rather larger overall rock population than at Gusev, and the dominant rock size is larger. The Viking 2 site is rockier still -- in fact, I would say that the Viking 2 site is non-navigable by a rover the size of the MER, and the Viking 1 and Pathfinder sites are semi-navigable.

Ditto. Every time I see a picture of the Viking 2 site, I think "Pathfinder and the MERs would have
been S.O.L. here..."

The dunes at the Viking 1 site also might have been a rude surprise for a less-cautious or experienced rover team, if driven into. The ones nearest the lander seem to have been much larger than any Opportunity has seen yet, though scale is difficult to determine.

[Cugel]

Just some last remarks on the 4 versus 6 wheels: both MER rovers benefitted from their 6 wheel design for at least one time: when they left the lander. The lander was absolutely the single most biggest obstacle both rovers have ever rolled over. MSL doesn't need to roll of a lander, it IS a lander. I'm afraid the guys at JPL are so fond of their 6 wheels, which has become the hallmark of the rovers (they even patented it), we will never get rid of it.

Another small point: a double rocker-bogie system will give you (slightly) better reduced tilt values when crossing obstacles compared to a single system, it's something that can quite easily be computed. However, I think that rocks that really require all 6 wheels are actually so large the EDL team will never allow you to land in their vicinity. They are at least visible (HIRISE) from orbit, so one can simply navigate around them.

[edstrick]

dvandorn: ..."I've never heard a good geological discussion as to why the Viking 2 site is so densely rock-strewn, ..."

Viking 2's site has been thought to be on a lobe of ejecta flow from the large impact crater "Mie" to the east. The lobate flow patterns seem to extend west to the landing site, but fine details of the surface in Viking or Global Surveyor / Odyssey images don't seem to show much difference between ejecta lobes and areas to the west. HiRISE and the spectral mapper may clear this up. I have no idea what THEMIS thermal data indicate about rock abundance in and outside the ejecta lobe zone.

[Guest_Richard Trigaux_*]

Most martian rocks are basalt, and, when cooling, basalt fractures itself into blocks, size of them is relatively constant. of course from a flow to another, the average sizes varies, but remains in the tens of centemetres. We cannot expect to find larger blocks like 10m wide granite blocks. The only exception to date seems some tuffs seen by Spirit when coming down of Husband Hill.

[odave]

Actually, pathfinding is quite common in modern computer games (shooters).

Very true, and the pathfinding in some games is quite sophisticated, but that problem is much more constrained than the one facing a rover on another planet. A game has 3D models and other factors affecting motion like water or ice, and these are all well defined per the rules laid out in the software. The pathfinding can be optimized for all of those rules. The rover's problems are not so well defined. It needs to construct its own 3D models on-the-fly from its vision sensors (cameras and lasers and the like), and motion factors like slippage are not constant. There's also realtime feedback to be processed from the motors etc. as the move is happening. And the rover's CPU isn't as beefy as today's average gaming machine, so it's harder to chunk through all of that code.

Having said that, I agree that the pathfinding algorithms developed for the gaming industry could certainly be considered in a rover.

[RNeuhaus]

Hypothetically, you could have inflatable wheels that would be filled with a quick-setting spongy foam during inflation. That way, maintaining pressure during a long mission life wouldn't be critical.

You might have problems maintaining wheel temperature at a reasonable level during foam curing, or coming up with a foam that would cure at suitably low temperatures.

I don't invite a foam to expand the wheel size, I would prefer the elasticity of a metal due to the reactivity of Martian surface and the large swings of temperature that will shorten the foam life (I think it so unless I am wrong if there is a new technology that overcomes these problems).

Rodolfo

[Bob Shaw]

...I agree that the pathfinding algorithms developed for the gaming industry could certainly be considered in a rover.

oDave:

That could be a problem, what with MSL's sample laser - not only have we declared war on a defenceless comet, but presumably the G&N software will be written by iD (and the blaster, oops laser, gets built by UAC!)...

...so they'll never find anything alive, all the beasties will have run away!

Bob Shaw

[odave]

I always preferred the BFG9000 myself

The possibilities are endless!

[ljk4-1]

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FWIW -

The film version of Doom does take place on a future Mars base:

http://en.wikipedia.org/wiki/Doom_%28film%29

[MaxSt]

And the rover's CPU isn't as beefy as today's average gaming machine, so it's harder to chunk through all of that code.

That's correct. But if the rover's goal is 100m per day, that's plenty of time to "stop and think" every 2-3m. Using a lot of RAM should help too. MRO has 20 Gb of memory, so I guess it shouldn't be a problem.

[RNeuhaus]

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However, the facility of detect and hazard avoidance would need an adequate programming software to manage it. Since the MSL CPU is based of RAD 750 which only runs the Operating System VxWorks which, I don't know much about its goodness to hold a software for Artificial Intelligence purposes, is very well suited for real time operations due to its reliability, adaptability, multitasking and versatiblity to work with its peripheral dispositives and also of its diagnosticability (easy debugging).

Rodolfo

[MaxSt]

Well, even MERs have some hazard avoidance software, and it runs on VxWorks too.

Not much RAM, though...