Printable Version of Topic

Posted by: AlexBlackwell Jan 18 2006, 03:57 PM

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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
* * * * * * * * * * * * * * * * * * * * * * * * *

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 and Matt Golombek
Co-Chairs, Mars Landing Site Steering Committee

Posted by: CosmicRocker Jan 23 2006, 06:37 AM

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
* * * * * * * * * * * * * * * * * * * * * * * * *

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

* * * * * * * * * * * * * * * * * * * * * * * *
FIRST ANNOUNCEMENT FIRST ANNOUNCEMENT
* * * * * * * * * * * * * * * * * * * * * * * * *

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

Posted by: odave Jan 23 2006, 03:13 PM

I found the minutes of the http://marsoweb.nas.nasa.gov/landingsites/ fascinating reading, especially in light of what the MERs actually found. There's certainly a lot of give-and-take. It also shows how much more work will need to be done in picking a site for MSL, given its more flexible capabilities.

And you've got to love a steering committee that will meet at a place called "BJOs Pub and Brewery"

Posted by: exobioquest Jan 23 2006, 07:44 PM

Shouldn’t this be moved to the MSL sub-forum?

So do any of you guys think the areas Mars Express found hydrated silicates (implying long time exposures to neutral or alkaline water) at are primary targets?

Posted by: paulanderson Jan 23 2006, 10:15 PM

Absolutely. More so than the acidic sulphate areas, at least in terms of possible past biological evidence.

Posted by: AlexBlackwell Jan 23 2006, 11:08 PM

That's a good idea, and I should have placed it there to begin with (actually, I thought I did). Maybe Doug or one of the "trustees" can do it?

Posted by: djellison Jan 23 2006, 11:20 PM

Done

Doug

Posted by: AlexBlackwell Jan 23 2006, 11:43 PM

I agree. In fact, I think the MER landing sites selection story was just as fascinating as the engineering story (e.g., the development headaches of the EDL systems). However, except for some coverage in Squyres's book, the former is hardly mentioned in the popular literature. I guess shredded parachutes and airbags makes for a "sexier" story, not to mention better visuals, than, say, the PowerPoint presentations giving the relative merits of Athabasca Valles over Gusev Crater.

Posted by: AlexBlackwell Jan 23 2006, 11:44 PM

Thanks, Doug.

Posted by: elakdawalla Jan 24 2006, 03:20 AM

It was completely fascinating to watch -- and I was lucky enough to attend three of the meetings. Those of you who are Society members may have seen an article I wrote about the site selection process for The Planetary Report (it was the May/June 2003 issue). At one point when they were fretting about airbag and parachute problems they had eliminated every single possible landing site except Meridiani, and even at that site there was some concern about winds. Fortunately as testing and development proceeded, and as more MOC images came back, they were able to relax the constraints just enough to permit them to send four site recommendations upstairs. I hope I get to see the whole process again for MSL...

--Emily

Posted by: BruceMoomaw Jan 24 2006, 05:11 AM

Which certainly shows the vulnerability of the airbag system.

Posted by: edstrick Jan 24 2006, 10:03 AM

I'd really like to see a retrospective on the MER site selection. They had Meridiani dead on, but in retrospect, Gusev was a bad pick, turned lucky only by the total luck of the rover's long life and relative closeness of the hills.

Some of the geologists proposing sites were saying "I TOLD YOU SO" after the lakebed turned out to have impenetrable armor of some tens (probably) of meters of basalt. I'd like a good idea how the "it's not lakebed, it's basalt" arguements lost during the selection process.

Posted by: djellison Jan 24 2006, 10:08 AM

MSL's landing site HAS to be a good one - I dont think they can make the call until MRO is there. There's be some case for Meridiani I'm sure, or perhaps other Hematite sites - but I can't imagine them wanting to use a low altitude site given all the money and effort being spent on making higher altitude sites accesable.

It's not a decision I'd like to make.

Doug

Posted by: Burmese Jan 24 2006, 01:35 PM

I suspect they may go to Meridiani in any case. It is a known quantity, clearly has had water in the past, and MSL could cover huge distances in that terrain.

Posted by: Phil Stooke Jan 24 2006, 01:47 PM

The story of site selection is one I am particularly interested in, and it's one I am covering in depth in my moon atlas. Next step is a Mars version, and you can be sure I will be covering all this in detail. It was great to have access to all that material for Mars 2001 and MER on the Ames website, and I hope we will see it again for MER. Phoenix has not been as open, but that's because the regional-level selection is fixed from the start by the mission definition. We should see more after they down-select from three areas to one this summer, and then the actual ellipse definition begins.

I find it hard to imagine that MSL will not go to one of the layered outcrop areas. But there are lots of them. I don't think there is any reason to go back to the Opportunity region, though areas to the north where the evaporites are widely exposed could be candidates. Being a known quantity works against it, not for it. But there are so many places with great stacks of exposed layers to compete with it... or maybe the floors of the great sedimentary basins.

I have only recently come to terms with the idea that MSL could operate for a decade... looking at the recent list of proposed missions, I was frustrated that there was so long between rover missions, but there won't be unless we have a failure. But that implies that MSL must choose a place with an excellent primary mission goal, and also lots of scope for a very long extended mission. A one-target site won't do unless it is of outstanding scientific value. Perhaps for that reason a 'White Rock' type site in a crater may be too restrictive.

Phil

Posted by: AlexBlackwell Jan 24 2006, 07:05 PM

Frankly, I think that's an oversimplification of what really happened. I don't think it's fair (let alone accurate) to imply that all those who favored Gusev Crater be described as positing "it's a lakebed, not basalt," which is the corollary to your descriptor above of the "I TOLD YOU SO" crowd. Most scientists knew going in that Gusev had been mantled by massive deposits of aeolian and volcanic sediments; the hope was that buried lacustrine sediments would be accessible at the surface, most likely in crater ejecta blankets. And the lousy landing ellipse didn't help, either

Posted by: AlexBlackwell Jan 24 2006, 07:18 PM

I wouldn't be surprised if that turned out to be the case. I also think everyone should bear in mind that MSL is primarily a geological mission, with one of the goals to search for paleo-habitats; it is not per se an astrobiological mission. The landing site that is selected undoubtedly will reflect this.

EDIT: Given the stated http://marsprogram.jpl.nasa.gov/msl/science/objectives.html, I probably should have been more precise above, so I'll substitute "geoscientific" for "geological."

Posted by: BruceMoomaw Jan 24 2006, 10:06 PM

Of course, one reason they went for Gusev is that more scientifically attractive sites (the bottom of Valles Marineris, Athabasca) turned out to be unacceptable for engineering safety reasons. By the time of the final selection, the only possible choice was between Gusev and a low-wind but scientifically less interesting site in Elysium. As far as I'm concerned, they did the right thing -- as Alex says, while a lot of Gusev's floor was known to be lava-flow covered, there was considerable hope that they could get close enough to some other kind of more interesting exposed surface (maybe through crater ejecta), and in the end, thanks to the rover's staying power, they did just that. The Columbia Hills seem to be providing us with a typical portrayal of what the surface of Noachian Mars was like, as opposed to the unusual Meridiani environment.

But this also proves again that we urgently need a better landing system -- both much smaller ellipses (which would have opened up a tremendous number of nice alternatives for the MERs), and a more durable final landing system. The sooner we develop these, the better -- and if we have to actually delay some landing missions in order to acquire these technologies, we should.

As for MSL: it is indeed definitely premature to peg the clay deposits as probable landing sites -- especially given the huge amount of information MRO should provide us -- but I'd definitely agree that they are the front-runners at the moment. The OMEGA team has emphasized that these were far more hospitable locations for the appearance of microbial life than the acid-deposited sulfate beds like Meridiani; and one thing that was emphasized repeatedly at last January's meeting of the Mars Strategic Roadmap group was that MSL's most important purpose is to locate a place that's rich in trace organics that may be biological fossils. If MSL finds such a place, it might be advisable to cut to the chase by eliminating any 2016 rover and pouring its money directly into accelerated development of a sample-return mission to the same place. If MSL does not find trace organics, I think it's virtually mandatory to fly some kind of mission in 2016 to look elsewhere -- whether it's the AFL, a second MSL, two small MER-class rovers with organic detection capability (if this is possible), or a stationary Deep Drill lander.

In this connection, by the way, the new MEPAG report contains one alarming eyebrow-raiser about a possible serious show-stopper in the search for Martian organics which I have never heard a word about before -- and which I'll describe in this site's thread on the MEPAG report.

Posted by: AlexBlackwell Feb 14 2006, 05:00 PM

Registration for the workshop is now (apparently) open. Click http://marsoweb.nas.nasa.gov/landingsites/ or http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop_announcement.html to register and/or submit an abstract(s). The only problem, though, at least for me, is that the features (which use Java scripts) don't seem to work at the moment.

Posted by: AlexBlackwell Mar 8 2006, 07:39 PM

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SECOND ANNOUNCEMENT SECOND ANNOUNCEMENT
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CALL FOR ABSTRACTS

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

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SECOND ANNOUNCEMENT SECOND ANNOUNCEMENT
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Dear Colleagues:

We are writing to remind you that abstracts for the First Landing Site Workshop for the 2009 Mars Science Laboratory mission (MSL) are due on March 28, 2006 (no exceptions!). The workshop will be held May 31 through June 2, 2006, at the Pasadena Conference/Convention Center in Old town Pasadena, CA. Information on local hotels can be found at http://www.pasadenacal.com/hotelmotel.htm. Web sites describing MSL landing site selection activities are http://marsoweb.nas.nasa.gov/landingsites/ and the USGS PIGWAD site http://webgis.wr.usgs.gov/msl.

There will not be a registration fee for the workshop, but interested individuals wishing to attend should indicate their intent to do so via http://marsoweb.nas.nasa.gov/landingsites/ by April 1, 2006, so that we can ensure adequate meeting space.

SUMMARY OF WORKSHOP OBJECTIVES:

As noted in the first announcement, the purpose of the first MSL 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 prioritizing and subsequently 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 enormous because MSL entry, descent, and landing capabilities enable a small landing error ellipse, high elevation (<2 km), and wide latitudes (±60°) relative to prior Mars missions.

ABSTRACT SUBMISSION:

As the deadline for abstract submission approaches, we would like to remind you that a series of relevant documents have been posted on the two websites: http://marsoweb.nas.nasa.gov/landingsites/ and http://webgis.wr.usgs.gov/msl. These include a "Users Guide" describing the engineering constraints imposed on potential landing sites, a package on the MSL mission, science objectives, and instruments, and the governing document on planetary protection. It is anticipated that most presentations will be oral, though there may be some additional space for poster presentations. All persons interested in participating in the workshop must review these constraints carefully to ensure that proposed sites can be considered.

Individuals wishing to advocate the overall types of sites or a particular site or sites at the workshop are required to submit an abstract electronically via http://marsoweb.nas.nasa.gov/landingsites/. Individual abstracts can include multiple proposed sites, but are limited to one page in length in LPSC abstract style. Abstracts must be electronically submitted in either PDF (strongly preferred) or in Word (DOC) file format. Detailed instructions on abstract submission are also posted at this web site.

The First Announcement includes summaries of the science objectives, engineering and planetary protection constraints, and the types of papers being sought. The program for the workshop will be constructed from the abstract submissions and will be sent around with the Third Announcement in April 2006.

All members of the scientific community are encouraged to participate in this important activity. Input from the science community is critical to the 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

Posted by: AlexBlackwell Mar 10 2006, 08:43 PM

Did anyone notice the new MSL-related documentation (see either website above) that came out with the second announcement? There are a couple of engineering constraints-related documents and one (a letter from PPO John Rummel) related to planetary protection.

Posted by: Phil Stooke Apr 20 2006, 01:53 AM

Abstracts are up on the Ames site:

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/program.html

Phil

Posted by: RNeuhaus Apr 20 2006, 02:24 AM

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Rafkin_1st_MSL_workshop.pdf

Interesting article. This article says that the northern hemisphere has softer maximum wind speed in general than the southern hemisphere ones. The average maximum wind speed increases from the north to south of hemipshere except to inside of Hellas basin. The strongest wind are around the tharsis mountains. The sites of Meridani Planum and Gusev craters are in the maximum wind speed average

The maximum in southern middle latitudes is a product of the polar jet, which is strongest during the winter. There is also a modest correlation of wind speeds with topography; the highest terrain has the strongest winds.

Hence, the southern hemisphere is not a good landing zone for MSL since the restriction for landing is that the wind won't be over than 30 m/sec from 10 km to surface. But, there is more investigation since the wind speed varies according to the windows of time of day.

Rodolfo

Posted by: RNeuhaus Apr 23 2006, 03:30 AM

A target for future mission. Probably, the next mission, MSL will be the next turn.

If Martian life ever did exist, it could probably have only survived during the first era, the team reports. And evidence for that life is most likely to be found in the Syrtis Major volcanic plateau, in Nili Fossae and in the Marwth Vallis Regions, two regions rich in the clay minerals abundant during Mars' youth. The researchers added that these areas would make compelling targets for future lander missions.

Where do you want to visit?

Rodolfo

Posted by: edstrick Apr 23 2006, 07:06 AM

The clay-rich areas interpreted as being formed in very early low-acidity "warm-wet" conditions are a very enticing target.

I would be very reluctant to go to an area like the badlands of northeast Meridiani where hundreds of meters of sulfate (presumably) rocks are exposed in intricately eroded deposits, if those are the only dominant type of non-basalt rock.

Similarly, I'd be reluctant to go to an area where the only really interesting "different" type of rock exposed is the clay-bearing deposits.

The highest science value landing sites for MSL will be ones where there is profound geologic diversity with materials of widly varying age and composition within the primary mission driving requirement range of the landing ellipse.

A second requirement should be that the materials be well exposed. If Spirit had landed outside the dust-scoured low albedo region in Gusev (in 2/3 of the landing ellipse!), the surface would have been much more pervasively dusted with geology obscuring redish storm fallout dust. Imagine the difficulty of Spirit doing it's geology in the hills if 90 or 99% of the rock and soil surfaces were more or less uniformly dusted and red.

I have a soft spot in my innards for the Melas Chasma site that was a real candidate for Opportunity before models indicated high down-valley winds would be a hazard to landing. I don't know the current state of OMEGA composition mapping in that area, but the geology of the Valles floor deposits in much of that area appears wildly diverse in structure and apparently composition. It wouldn't hurt that the view from inside the canyon would be bogglaceous.

Posted by: BruceMoomaw Apr 23 2006, 09:41 AM

In that connection, keep in mind that the Mawrth Vallis area which seems to be one of the richest exposed deposits of Noachian phyllosilicates also alternates them with Hesperian flows of unaltered olivine -- and the phyllosilicates are frequently exposed on the upper slopes of giant Hesperian outflow channels.

Posted by: edstrick Apr 23 2006, 09:54 AM

The site is certainly a place to take a very close look at... as is (I'd have to check) Aram Chaos. I'm a sucker for scenery, but science has an overwhelming priority. And from what I've seen as I've skim-browsed the abstracts, both regions have serious geologic complexity within fairly short driving distances.

Posted by: Richard Trigaux Apr 23 2006, 11:42 AM

Please if somebody had some idea of the rover capacity? The length of path it may do during the entire mission, or in one day, the expected mission duration, wheels diametre, navigation capacity, etc. I think it is important, as probably none site is of "primary science interest", on the countrary they may try to reach a more interesting site and after visit neighbouring sites. (To the countrary of Spirit and Oppy, which were bound to one site only)

To recall, the total surface of Mars is about like Earth's continents, and it takes 10,000kms to go on the other side. This is still far beyond the possibilities of any planned rover, so they need to carefully select their sites.

Posted by: Cugel Apr 23 2006, 02:19 PM

http://www.nuclearspace.com/a_2009_Rover.htm
This article talks about 'miles'.

http://space.com/businesstechnology/060118_msl_wheels.html
Is talking about 'hundreds of meters per day'.

Other sources talk about 10 km. during its lifetime of 2 Earth years.

To speculate a bit about really max. performance, if it can do 250 meter drives on average a sol and it would drive on 25% of the sols this would result in: 180 x 0.250 = 45 km. during its lifetime on Mars.
Impressive, but I think we're still talking about a single site mission really. There is no way it would chalk up hundreds of kilometers. Besides being nuclear powered I think the greatest performance increase must come from software development. With all the lessons from MER under the belt it must be possible to build really better autonomous driving programs. I would think.

Posted by: Phil Stooke Apr 23 2006, 03:24 PM

We do get mixed messages about daily and total range, probably from sources written at different times as their thinking evolves. I think the MSL workshop website says (somewhere) that 20 km in the primary mission is the current expectation.

Most likely, there would be intensive study of one site with limited driving, then a drive of a few km and intensive study of a second site, and so on. A bit like Opportunity at Eagle, then Endurance, then Erebus. An ideal site will be one with a safe landing point, excellent science at several points within about 10 km for the primary mission, and a good range of targets for an extended mission.

To my mind the key to range will be the nature of the software governing driving. If the site has a fair bit of relief, as I would expect, the ability to plan drives over a few hundred metres will be limited even with MRO data. A longer drive in one day will require automated hazard avoidance capability. But if you detect a hazard, what do you do? If you stop and wait for instructions, driving will be slow. If you can try multiple paths until a safe route is found to the designated target, driving longer distances in a day is more feasible. For instance, we might imaging the planners giving instructions to follow a pre-planned route, but offering alternative routes to the same place based on MRO data. If MSL is stopped by an unexpected hazard, it could search locally for a way round the hazard, or retrace its steps to a branch point and follow the second alternative route, without intervention from the ground. That would be faster. But I don't know anything about the strategy to be followed on MSL.

Phil

Posted by: mcaplinger Apr 23 2006, 04:10 PM

Definitely true. And one has to consider the source too; there appears to be little consensus yet about what MSL operations will actually look like.

The current engineering constraints document says this:

"As part of its primary mission, the MSL rover would include the capability for traversing long distances. Currently, the system is being designed for a total actual traverse distance capability of no less than 20 km. For purposes of hardware life and cycle evaluation, it is assumed that this traverse occurs over a terrain with an average rock abundance of 15%, an average slope of 5 degrees, and an average slip rate of 10%. Under these conditions the rover would travel on average about 100-150 m/sol."

But Phil is probably correct that a lot of time will be spent at a particular site before moving on to the next site (as I understand it it takes a fair bit of time for SAM and Chemin to do their things), so the per-sol average traverse is probably not representative.

Posted by: Richard Trigaux Apr 23 2006, 05:05 PM

I agree with both of you. Autonomous capability is the key for long range and several targets.

I would add that they should design the rovers with a long lifetime and long range. It would add a bit of weight (for instance the only way to increase the lifetime of a ball bearing is to increase its size) but this extra cost will be recovered with less launchs. Provided of course that there are enough science targets within range.

Posted by: mcaplinger Apr 23 2006, 05:19 PM

I agree too, for suitable definitions of "autonomous", "long", and "several". But for autonomy as JPL has implemented it on MER, and for the range of MER, the autonomy is not frequently used because it doesn't work well enough to do anything but the simplest tasks. Certainly there's no high-level route planning like the sort Phil mentioned. And I'd be surprised if MSL will have or need any more autonomy than MER given the relatively small traverse distance they're talking about.

Now, we're currently working on a much smaller rover with much simpler autonomy that would have longer range (see http://www.amerobotics.ou.edu/research/sr2/ ), but I don't believe JPL is thinking along those lines.

Posted by: Richard Trigaux Apr 23 2006, 06:13 PM

software has no weight! The only harware which could add autonomy are a LIDAR (to have a true 3D scenery without using error-prone stereo vision) and a better aaptative wheel suspension. Otherwise to add "intelligence" into the software (such as alternate routes) adds cost only in the development stage. This cost is well repaid at time of roving on bad terrain, finding unexpected target, or getting the rover out of a dune or loose rocks.

Posted by: mcaplinger Apr 23 2006, 06:40 PM

Have you ever tried to write autonomy software? Regardless of what the typical AI/robotics researcher will claim, reliable high-level autonomy of the sort being discussed is well beyond the state of the art.

You might want to read about the work of Rod Brooks -- http://www.kk.org/outofcontrol/contents.php -- for a discussion of the sort of autonomy we're working on.

Posted by: Cugel Apr 23 2006, 07:25 PM

Funny that you mention it. It's how I make a living! Unfortunately, I must agree with you. We are far from completely autonomous rover navigation software. But some things speak in our favor:

1. As being a relatively young field of interest, really substantial progress is possible within the next few years.
2. Our militairy friends are very interested in this, as more and more of their systems are becoming unmanned.
And because they are the ones with the big budgets and other resources we can hope to see some serious results. (A lot of people are currently working on this, it's big business!)
3. Computer hardware and sensor development is also on our side (Moore's law).
4. We don't need completely autonomous navigation right now, an incremental improvement would be fine and give us much.

Personally, I think with MSL it should be possible to do 1 km. drives completely autonomously (taking a week or so without further commands) in a Meridiani like environment. No science target selection, of course. Just obstacle detection and avoidance.

Posted by: J.J. Apr 23 2006, 07:30 PM

I'm personally jonesing for Eberswalde Delta...I think the science in the delta proper, the crater floor, and the crater walls (presumably an old shoreline) would be fantastic.

Posted by: RNeuhaus Apr 23 2006, 07:43 PM

I think that the one of the factors that limited the MER's autonomy is due to the fact that their surface image from MGS and/or Odyssey does not provide enough surface resolution as the MRO will provide to MSL. On the other hand, one of the most important keys for the longer autonomy is due to the low height of the MER's mast PANCAM (1.4 m) that hinder the capability to anticipate better the forward surface conditions.

Rodolfo


It is a very complicated matter to develop a high intelligence software to detect the subtle difference among the different kind of sand (loose and compact), besides takes the degree of slope, temperature of sand (hot sand, is sleeper since it is drier, wet sand, is better for traction) and also the relieve of sand also takes into the account on how to maximize the traction. On the other matter, about the safety, to decide to go whenever every aspects are meet the safety rules such as the stone height, slope, loose surface, wet surface, slippery surface and even inclusive any bigger saps that might appear than ones of often of Meridiani.

On the overall, I think we still have very little experience about the tricks of Mars surface. So the MSL must continue driving with care since it is still one of the space pioneers!

Rodolfo

Posted by: mcaplinger Apr 23 2006, 07:56 PM

Well, maybe; of course, AI researchers have been saying exactly the same thing since the early '80s. The DARPA Grand Challenge ( http://www.darpa.mil/grandchallenge/ ) does lend some credence to the state of the art, but while software may weigh nothing, the hardware and sensors that drove the Grand Challenge vehicles were orders of magnitude heavier than what we could put on a Mars rover. (Memory and CPU cycles to run that software at usable speeds certainly weighs something!) Also, I think all the GC vehicles had to do was stay on the road, which is a totally different problem than that faced by a Mars rover.

Another point: most unmanned military vehicles, UCAVs for example, are teleoperated, not autonomous. The exceptions are those that fly simple courses with no sensors, like Global Hawk.

I stand by my original statement: we are nowhere close to deploying useful high-level autonomy on Mars.

Posted by: Richard Trigaux Apr 23 2006, 08:19 PM

Yes, certainly. But some could be gained, relative to Oppy and Spirit, which could make a difference. More autonomy should certainly be possible without adding much mass, and within reach of the team who will actually write the programs. For instance trying alternative route when one don't work requires just adding lines of code, and it could save a day of roving at some occasions. Or having a fan of acceptable paths. The road is found by try and mistakes, actual computers are good for this.

Posted by: Jeff7 Apr 23 2006, 08:27 PM

True, but a computer powerful enough to run that software at a respectable speed does have weight. The MER's only use a 20MHz processor.
A more powerful computer may be slightly larger, and it will require more power.


And the other problem is, making a computer that has some degree of intelligence is difficult. Computers are stupid. Incredibly, unbelievably stupid. They will do only what they are told, nothing more, nothing less. If a rover is told to drive over a cliff, or into an obstruction that will damage it, it will dutifully do it, unless a programmer early on told it specifically not to do that. And if the programmer tells it "Don't drive into obstructions that slope 50 degrees to the left," and you try to drive the rover into something sloping the other direction, it'll smack right into it without a second thought.

That's just basic object avoidance. 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.

Add to all of that that you want some kind of fault mode programming buried in there for when something goes wrong, like what happened with Spirit's flash memory problem. Fortunately, it had a fault mode that allowed for very low-level functionality.


That just amused me briefly - the MER's are already around 7km each.
But I get MSL would catch up to that mark very quickly.

Posted by: Phil Stooke Apr 23 2006, 08:47 PM

I should probably make it clear that I am aware of the difficulty of programming autonomy into the driving.

In answer to one point, I wasn't thinking that the rover would do its own route selection, or multi-route planning, but that those things would be done on earth before each drive. The rover would follow a plan until an obstacle stopped it - and of course the plan would already avoid most of them. But once you are stopped by an unexpected obstacle, instead of stopping right there, you would ideally be able to back up one or two metres, check for safety to the left and right, and take a detour to try to get around the obstacle and back on the pre-planned track. Spirit does this now, from time to time - there have been instances well recorded in images of the tracks, for instance at Arad on 716 and just coming down off Home Plate on 779. I think a bit of improvement in that line is not unreasonable and would be very productive.

Phil

Posted by: The Messenger Apr 23 2006, 09:04 PM

I notice in the mission planning, they recommend in situ measurements of temperature, density and pressure during descent at a sampling rate of 100 Hz. I think that with current techology, this could be quaddrupled with no weight penalty, and I would add a least three axis of acceleration to the mix, and an attempt should be made to telemeter all of this data in real time.

After seeing the dynamic buffeting both MER's suffered, the more data during this phase, the better.

Posted by: BruceMoomaw Apr 24 2006, 01:01 AM

Back in June 2002, the MSL science steering group wanted MSL to have substantial onboard autonomy allowing it to drive between its locations for detailed sampling and study at the rate of fully 450 meters/sol, or 3 km in 13 sols -- and, once it arrived, to "be able to approach a designated target, deploy the instrument arm, mini-corer, or drill, and begin science activities (measurements or drilling/coring), using only a single command cycle to initiate the full suite of activity." ( http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/9684/1/02-1822.pdf ) . A typical plan based on this idea involved it, during 667 sols of operation, driving about 69 km to study 23 different detailed study locations for about 16.5 sols each.

Unfortunately, that plan then went a-glimmering, and they went back to the MER level of driving and target-approach autonomy ( http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38317/1/03-2974.pdf ; http://www.ninfinger.org/~sven/models/vault2004/pip-drft_031121secure31.pdf ), in which it would traverses only about 50 meters/sol and take a 3-sol cycle to approach any particular sampling target at one of its detailed study locations. For the reasons, see the first of those two documents, pg. 147:

"(1) PSlG wanted to balance science and engineering sophistication: Mission life driven much less by driving range, speed or hazard detection autonomy than by number of science decisions requiring human interaction at a rock sample site.

"(2) Large vehicle size allows for simple path planning.

"(3) Consistent with an 'autonomy to cost' strategy:
Hazard detection and avoidance test cost could be unbounded.
Could infuse more autonomy once science objectives are met."
______________________________


Assuming, again, that MSL spent a total of about 381 sols at its detailed study locations, it could drive only about 1/9 as far as in the earlier plan -- that is, about 7.7 km. And the new plan called for it to acquire 74 samples, each of which would now take about 7 sols to approach and collect -- so we're talking only about 150 sols worth of driving at 50 meters/sol, which again came out to only about 7.5 km.

Well. Now we're back up to an ability to traverse 100-150 meters/sol during long drives, so -- assuming that we still plan to spend about 380 sols collecting samples -- we are indeed back up to 15 to 22.5 km total drive distance.

Posted by: Stephen Apr 24 2006, 02:17 AM

Emily's "Report from MEPAG" entry on http://planetary.org/blog/ reports Bruce Betts telling her that the MSL "will have a nominal mission distance of at least 20 kilometers".

======
Stephen

Posted by: Stephen Apr 24 2006, 02:43 AM

Timothy Parker's paper on Friday June 2 is listed on the program as "Mapping the proposed MSL landing sites" but the title the paper itself bears is "Unravelling Terby's Turbulent Past" and seems to be more concerned with advocating the merits Terby Crater than with mapping. Is this an error?

======
Stephen

Posted by: RNeuhaus Apr 24 2006, 02:58 AM

A good artificial intelligence for hazardous avoidance, needs a powerful CPU like a Pentium V or above in order to get a reasonable response time after some seconds. But, the MSL microprocessor might use ones IBM PowerPC RAD 750 (MER, MGS, ODY, Messenger, Spitzer, Pathfinder used RAD6000, Developed by IBM, similar to early members of PowerPC. he computer has a maximum clock rate of 33 MHz and a processing speed of about 35 MIPS. Its performance were inferior to Pentium IIs. A typical RTOS running on NASA's RAD6000 installations is VxWorks. Reported to have a unit cost somewhere between US$200,000 and US$300,000)

The RAD6000's successor is the RAD750 processor, based on Motorola/Freescale's PowerPC 750, and is used in NASA's latest Mars probe, the Mars Reconnaissance Orbiter and also probably to MSL. It is equivalent to IBM PowerPC 750 (32-bit). The CPU has 10.4 million CMOS transistors, nearly ten times more than its predecessor. It has a core clock of 133–166 MHz and can process at up to 300 MIPS, or greater with an extended L2 cache. The RAD750 system has a price tag in excess of US$200,000. The CPU power of RAD 750 is about to Pentium IIIs that is still very slow comparing to the present Pentium V runing its clock above than 3.0 Ghz.

Hence, MSL would have a high AI for hazardous avoidance maneuver as Richard would like. Then, the MSL will still rely much the drive command from the rover driver team. However, now, with the help of MRO with high resolution of surface pictures, will permit MSL choose smarter paths toward the desired target.

References, see http://en.wikipedia.org/wiki/RAD6000 and http://en.wikipedia.org/wiki/RAD750.

Rodolfo

Posted by: Phil Stooke Apr 24 2006, 03:00 AM

Yes, I saw that thing with Tim's paper too and I think it is an error. I think it might be changed closer to the time of the workshop.

Phil

Posted by: mcaplinger Apr 24 2006, 03:21 AM

Like I said back on page 3 of this thread -- http://www.unmannedspaceflight.com/index.php?s=&showtopic=2091&view=findpost&p=51558 -- they are now saying that the mission total is at least 20 km.

Posted by: BruceMoomaw Apr 24 2006, 03:46 AM

Yeah, the main news in that item was the specific reasons given why JPL finally rejected trying to develop improved autonomy for MSL's driving, as opposed to MER's.

Posted by: Stephen Apr 24 2006, 08:18 AM

That is not entirely true. The electronic ones and zeroes software is composed of may have no weight, but the hardware they reside in in order to do their job sure does, whether that be a CPU, RAM, flash memory, a hard drive, or whatever!

Furthermore, the more sophisticated a piece of software gets the more of those sorts of resources it will probably require in order to run efficiently (or at all). To give one example, a rover which needs to find its own way round will probably have some kind of map of its local surroundings sitting somewhere which tells it where it is, where it needs to go, where obstacles (and potential onstacles) are and what kind they are, what path it is currently following, what other path(s) it might be able to follow, and so forth.

The more autonomy you want to give a rover the more sophisticated, detailed, and extensive that map will have to be. Do you want it to be able to retrace its steps from potentially hazardous ground to safer ground? Then you're talking about a more detailed and sophisticated map which not only shows where the rover is now and where it hopes to go but also records where it has been and how it got from there to where it is now, the conditions (eg obstacles) it encountered along the way, etc.

Such a map is obviously going to be a larger and more complex than the one required by less capable software. It is also likely to grow as the rover covers more ground. (Which turn raises a whole heap of other issues I won't bother with here.) That in turn may require more RAM to hold the more sophisticated map, more space to hold the more sophisticated software which runs the more sophisticated map, and more computing power to run the software which runs the map.

The end result may well be an incredibly sophisticated and accomplished software package, but it may or may not be able to run on your existing rover. To accommodate it may require you to add more RAM, a faster CPU or multiple CPUs. Such changes in turn may require hardware changes of other sorts. For example, the more powerful CPU needed to run the more sophisticated software may also require a different motherboard; or it might produce more heat than the old processor, which in turn may require more sophisticated ways of dissipitating that heat. Or it may draw more power, which in turn may impact on the rover's power system.

In short, software may well have no weight as you say, but that does not mean it is weight-less.

======
Stephen

Posted by: centsworth_II Apr 24 2006, 05:20 PM

As I recall, Steve Squyres' retrospective wish list for the MERs includes six-wheel steering that would avoid repeated, time consuming back and forth jogs to reposition in front of a target or obstacle. Any chance of the MSL having six-wheel steering? Or is the thought of having six steering actuators subject to failure too scary?

Posted by: Cugel Apr 24 2006, 08:00 PM

Instead of adding two steering actuators it seems to make more sense to me to simply remove the two non-steering middle wheels. In other words, make it a single rocker-bogie suspension instead of a double. Make the (4) wheels a bit bigger and you end up with what Steve wanted at less weight and better equipped for crossing ripples. If you place the wheels far apart, it doesn't cost you much stability either.

Posted by: BruceMoomaw Apr 24 2006, 10:32 PM

No. They tested different designs right up the wazoo (both in computer simulations and in real situations), and the 6-wheel bogie consistently came out the best overall. This is one long-awaited space engineering decision -- the best design for a rover -- that now seems absolutely firm.

Posted by: mcaplinger Apr 24 2006, 11:32 PM

For a particular rock size and frequency, maybe. For the actual terrain at the MER landing sites, six wheels is serious overkill for rocks and the system is clearly quite challenged on dunes and drifts.

Posted by: BruceMoomaw Apr 25 2006, 12:14 AM

If you have room enough in your aeroshell to include much bigger wheels, a 4-wheel system MIGHT be better. I'll have to review my documents on this, if I can find them (and the time).

In any case, there is some consideration being given to switching over to big inflatable wheels on Mars rovers, which could change everything. Make them big enough and you can simply roll directly over all small obstacles, thereby tremendously simplifying your navigation needs and accelerating your daily progress. The question is whether they can be made durable enough, given all the trouble with the Pathfinder and MER airbags.

Posted by: lyford Apr 25 2006, 02:46 AM

Careful, Bruce, you're http://www.unmannedspaceflight.com/index.php?showtopic=789

Posted by: mcaplinger Apr 25 2006, 03:14 AM

Most places on Mars, it's quite easy to just drive around what few rocks there are. A modestly larger wheel might help, but inflatable wheels are hardly necessary. A four-wheel system would have no trouble at all at either MER site.

Posted by: RNeuhaus Apr 25 2006, 03:26 AM

Absolutely yes. A inflatable wheel must not be of a gas (better) but by mechanical expansion force soon after exploding a control pyro. The wheel must be totally of metal base. A bigger wheel, the rover will advance easier over any cracks, rug surface. Needs electrical motors more power than the smaller ones but the ridding is smoother and makes less effort to motors to overcome any small stones and sand due to its greater buoyance on the ripples or soft ground sand.

But, I think the MSL team has already sticked its design with 6 wheels. Isn't ?

Rodolfo

Posted by: MaxSt Apr 25 2006, 04:26 AM

Pathfinder's site was quite rocky...

Posted by: edstrick Apr 25 2006, 05:22 AM

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.

Posted by: dvandorn Apr 25 2006, 05:33 AM

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

Posted by: MaxSt Apr 25 2006, 05:54 AM

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.

Posted by: J.J. Apr 25 2006, 05:59 AM

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.

Posted by: Cugel Apr 25 2006, 08:15 AM

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.

Posted by: edstrick Apr 25 2006, 10:38 AM

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.

Posted by: Richard Trigaux Apr 25 2006, 10:49 AM

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.

Posted by: odave Apr 25 2006, 02:34 PM

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.

Posted by: RNeuhaus Apr 25 2006, 03:21 PM

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

Posted by: Bob Shaw Apr 25 2006, 03:29 PM

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

Posted by: odave Apr 25 2006, 03:38 PM

I always preferred the http://en.wikipedia.org/wiki/BFG9000 myself

The possibilities are endless!

Posted by: ljk4-1 Apr 25 2006, 03:46 PM

[quote name= quote in reply -removed
[/quote]

FWIW -

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

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

Posted by: MaxSt Apr 25 2006, 05:11 PM

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.

Posted by: RNeuhaus Apr 25 2006, 08:16 PM

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[/quote]
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

Posted by: MaxSt Apr 26 2006, 06:40 AM

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

Not much RAM, though...

Posted by: The Messenger Apr 26 2006, 03:20 PM

If we really wanted to know if there are viruses on Mars, we would have Bill Gate's design the software.

Posted by: Stephen Apr 28 2006, 09:20 AM

Well...yes. But how much of that 20 GB will actually be available in practice?

Data is stored in a 160 Gbit (20 GB) flash memory module consisting of over 700 memory chips, each with 256 Mbit capacities. This memory capacity is not actually that large, considering how much data is going to be acquired; for example, a single image from HiRISE camera can be as big as 28 Gbit [3.5 GB].

======
Stephen

Posted by: djellison Apr 28 2006, 09:36 AM

And - that storage is the slower non-volatile type. It's not 'Ram'.

If you want to process a lot of images for navigation purposes, you need plenty of ram with which to do it.

Strangely, I've never seen any reference to Hazcam's for MSL - I'm assuming they'll be installed front and rear- but will they be MER heritage, or fish-eye'd versions of the Mastcam electronics?

Either way - I think with improvements in software, we can get better at this than we are now. Compare current driving to, say, the drive to Bonneville crater - AND - we are due another MER software update in the not too distant future.

Doug

Posted by: BruceMoomaw Apr 29 2006, 08:59 AM

Here's yet another personal estimate from me as to some of the particular interesting abstracts at this workshop. (Proceed at your own risk.)

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Grotzinger_1st_MSL_workshop.pdf : Nice summary of the general scientiic criteria for picking landing sites -- including the varying potentials of different types of rocks and minerals for preserving ancient fossil evidence.

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Aubrey_1st_MSL_workshop.pdf : A related piece concluding, from analysis of Earth minerals, that sulfates actually do a much better job of preserving fossil organic compounds than hematite does. This is important -- and it may be related to Dawn Sumner's argument that what's likely to destroy fossil organics in an environment like Meridiani is the dissolved ferric iron in the water, more than the sulfuric acid: http://repositories.cdlib.org/cgi/viewcontent.cgi?article=2186&context=postprints

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Bibring_1st_MSL_workshop.pdf : The OMEGA team repeats its case for choosing one of the small areas of exposed Noachian phyllosilicates as the best possible places to look for fossil biological evidence. I still find this convincing.

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Dietrich_1st_MSL_workshop.pdf : A proposal that MSL might land on the floor of a large crater with gullies on the walls and roll up to inspect the bottoms of the gullies. "In the Wirtz Crater in particular...there are well developed gullies with at least one impact crater on a gully apron deposit suggesting sufficient antiquity to satisfy possible constraints on investigations due to planetary protection requirements (i.e. there might be no threat that the gully with the impact crater can become active in modern times)." Maybe.

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Allen_1st_MSL_workshop.pdf : Proposal to land in Arabia Terra, a very interesting region which is not only very rich in layered rocks that seem to be highly hydrated, but which may be one of Mars' main sources of methane.

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Burr_1st_MSL_workshop.pdf : Proposal to land in Athabasca Valles, which -- on top of its other interesting attributes -- is showing some slight evidence of hydrated minerals in OMEGA's maps ( http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1477.pdf ).

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Mustard_1st_MSL_workshop.pdf : Proposal to land in Nili Fossae, a site extremely rich in Noachian phyllosilicates nd just plain intereting all the way around. I suspect this will end up as one of the frontrunners.

http://marsoweb.nas.nasa.gov/landingsites/msl/workshops/1st_workshop/abstracts/Cabrol_1st_MSL_workshop.pdf : Proposal to land in Aram Chaos, a hematite site that may be more interesting (and acid-free) than Meridiani. (But see the cautions above about looking for fossil evidence in hematite deposits.)

Posted by: edstrick Apr 29 2006, 10:46 AM

"...Proposal to land in Arabia Terra..."

I would be extremely negative on that for the MSL mission, though I would extremely strongly support it for one of a netlander type mission station.

Viking IRTM InfraRed Therml Mapper data showed that non-polar Mars is divided into essentially two types of areas: Low thermal inertia and Intermediate to High thermal inertia. Much of Arabia is a moderately high to high albedo reddish terrain consisting almost entirely of low inertia surfaces. Very few features within Arabia (such as isolated dark "splotches" in a few craters) have intermediate or high inertia. Much of Tharsis, including the 4 great shield volcanoes are in low inertia terrain, as is much of eastern Amazonis.

A low inertia areas' surface is essentially entirely covered to a depth of at least a few centimeters with uncemented dust with a probable mechanical consistancy of cement powder. They heat up very rapidly during the day and cool off very fast at night. Intermediate inertia surfaces have thermal properties of fine sand or somewhat cemented dust, while relatively rare high to very high inertia surfaces have thermal properties of coarse sand or well cemented, probably mechanically hard material. Viking, Pathfinder, and MER all landed in intermediate to moderately high inertia terrain.

Thermal inertia is primarily measured by sampling the diurnal heating cycle. An afternoon and a predawn measurement are enough for a decent estimate, though daytime surface albedo measurements help a lot to put absolute values on the numbers. Really accurate numbers require the entire day/night heating/cooling curve, not accessible to polar orbiting sun-synchronous orbiters.

Viking could also detect "brightness temperature" differences between the short wavelength thermal channels and the long wavelength one. Large cobbles and rocks cool off slower than fine sand or dust at night, and the surface -- if you could see it in infrared color -- would be studded with glowing "bluish" hot-rocks on a dully glowing "reddish" cold backgrouind. Signal-to-noise on the data was soso, and the rock abundance maps were crude, but matched the Viking landing sites well. MGS TES data have supplanted the Viking data in resolution and SNR, and the rock abuncance estimates match pathfinder and MER decently.

What does this mean? ..... Arabia and the low inertia regions in general have near-zero calculated rock abundance. They're buried or mantled with dust. This dust is *NOT* the last few years's dust storm dust. It does have weak geographic thermal and matching albedo variations, while areas of recently deposited dust in Viking images (pre-vs-post 1977 storm images) are uniform in areas where they appear thick and nearly continuous .... till wind starts eroding the fresh fallout. Instead, it's probably some dust mantle deposited during some recent climatic cycle and not eroded. Arabia seems to be heavily mantled with dust in MOC and THEMIS images, but this is not necessarily the same unit, since the low inertia deposits that control color and albedo in the low inertia regions are sensed to a maxium depth of a very few centimeters, and mantling maps do not seem to precisely match low inertia region boundaries.

Either way, in most any area in Arabia and any low inertia region, geologic exposure of material "of interest" to MSL will be atrocious at best and non-existant at worst. Like the entirely dusted high-albedo regions on the floor of Gusev (that Spirit most fortuitiously missed!) only far worse.

Posted by: BruceMoomaw Apr 29 2006, 12:55 PM

Except that there seem to be a lot of areas in Arabia where there are very extensive displays of layered sedimentary rock -- and, given the small size of MSL's landing ellipse, the odds of its actually hitting one of them is vastly better than for past landers.

Posted by: edstrick Apr 30 2006, 07:29 AM

The thermal data indicate that much of the rock is very poorly exposed. A meter to centimeters of caked-on dust or dust mantle would be utterly invisible in current imaging except indirectly, as color/albedo/thermal patterns, which is what seems to be the case.

here *are* exposures of higher inertia within Arabia, for example dark splotches with intermediate albedo margins on the floor of Henry crater lie on the crater bottom to either side of the *BIG* layered sedimentary pile in the middle of the crater, but these are rare and limited.

The layered sedimentary rock in the crater itself seemed in the Viking data to have the same inertia as typical Arabia material.

Full resolution HiRISE images and hyperspectral composition maps across the transitions between dark splotches, intermediate albedo / intermediate inertia reddish borders and the higher albedo / low inertia materials of Arabia will shed a lot of light on the problem.

I'd really love to put a netlander type payload down in absolutely representative Arabia terrain and give us some ground truth on these important regions, but that's not going to happen any time soon

Posted by: ustrax Jun 1 2006, 03:48 PM

From Space.com:

Grant said that the current site constraints are very broad and allow consideration of sites at a range of elevations and latitudes not considered by Spirit and Opportunity Mars rover planners, for example.
...
Some scientists here are backing the Holden Crater region. Others suggest that Gale Crater is a feature likely to rise to the top of the must do list. Many point to a "no brainer" of an exploration hot spot—the huge canyon landscape of Valles Marineris.

"Valles Marineris looks good now … but remember the cold feet that the engineers got about this with Spirit and Opportunity. I wouldn’t be surprised if Valles Marineris eventually falls out of favor for engineering reasons," predicted one Mars researcher taking part in the workshop.



http://space.com/news/060531_msl_destination.html

Posted by: RNeuhaus Jun 5 2006, 01:27 AM

Wrong place for the topic. Removed the post.

Rodolfo