The following contains excerpts from the NASA's Mars Exploration Analysis Group white paper titled Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars [1.66MB PDF]. The report has been approved for public release by JPL Document Review Services (CL#05- 0381), and may be freely circulated.


The paper suggests the following four measurements on equal and highest priority:

• Study Particulates - Aeolian and regolith dust and particulates should be analyzed with sufficient accuracy to predict hardware and engineering interaction and develop credible modeling labs on Earth.
  
• Measure Atmospherics - Measure atmospheric variability for both Entry/Descent/Landing (EDL) and Takeoff/Ascent/Orbit Insertion (TAO) profiles from ground level to greater than 90km in both ambient and dust storm conditions.
  
• Avoid Replicants - "Determine if each martian site to be visited by humans is free, to within acceptable risk standards, of replicating bio-hazards which may have adverse effects on humans and other terrestrial species. Sampling into the subsurface for this investigation must extend to the maximum depth to which the human mission may come into contact with uncontained martian material."
  
• Locate Water - Potential sources of water should be characterized in case a future mission plan is determined to require In Situ Resource Utilization (ISRU) for reasons of affordability or safety. The white paper adds this caveat, "At this time it is not known where human exploration of Mars may occur."
  

The following six measurements are in descending order of lower priority:

1. Determine human toxicity potential of dust and particulates.
   
2. Determine the effect of atmospheric electricity on occupation, EVA and TAO.
   
3. Determine the effect of ionizing radiation at martian surface, "distinguishing contributions from the energetic charged particles that penetrate the atmosphere, secondary neutrons produced in the atmosphere, and secondary charged particles and neutrons produced in the regolith."
   
4. Determine traction and cohesion properties of soil and regolith at proposed landing sites.
   
5. Determine ground-level meteorological properties of dust storms and potential effects on occupation and EVA.

The paper itself provides much greater detail into the precursor planning and assumes that the robotic precursor missions take place during the 2011 launch opportunity. The executive summary can be found here for those so inclined. Very interesting.

This white paper was developed by David W. Beaty (Mars Program Office-JPL/Caltech), Kelly Snook (JSC/NASA HQ), Carlton Allen (JSC), Dean Eppler (SAIC), Bill Farrell (GSFC), Jennifer Heldmann (ARC), Phil Metzger (KSC), Lewis Peach (USRA), Sandy Wagner (JSC), and Cary Zeitlin (Lawrence Berkeley), on behalf of the Mars Human Precursor Science Steering Group (MHP SSG). [/CREDITS]

__________________
In the progress of this discussion I shall endeavor to give a satisfactory answer to all the objections which shall have made their appearance, that may seem to have any claim to your attention.

Alexander Hamilton, Federalist No. 1

Anyone feel like posting over at GLP?

and

It shouldn't be that hard to spin that into a unified conspiracy theory.

__________________
In the progress of this discussion I shall endeavor to give a satisfactory answer to all the objections which shall have made their appearance, that may seem to have any claim to your attention.

Alexander Hamilton, Federalist No. 1

[quote="Cylinder"]The following contains excerpts from the NASA's Mars Exploration Analysis Group white paper titled Precursor Measurements of Mars Needed to Reduce the Risk of the First Human Mission to Mars [1.66MB PDF]. The report has been approved for public release by JPL Document Review Services (CL#05- 0381), and may be freely circulated.

8)

__________________
jwj

It's ok not to know. We should try harder to find out.

Just finished reading the document. It certainly looks as if they have all the critical measurements covered. However one thing does surprise me.

At the time of Pathfinder/Sojourner it was originally intended that the mission serve as a testbed for a network of 'Pathfinder-style' landers spread across the face of Mars. This was cancelled due to rising costs before the launch of the testbed which then became the main mission.

Why hasn't anyone proposed reviving the concept? It would seem to be the perfect way to gather much of the radiation data and build up a 'ground-level' view of Martian weather.

As for costs, surely it would cost less to revive flight tested technologies than to build a completely new lander design.

Comments...

If they're going to send a bunch of any sort of probes, I'd vote for MER-style rovers over Pathfinder-style stationary landers. In any case, my recollection is that Pathfinder was primarily an engineering mission designed to test the "bouncing balloon" approach to landing probes on Mars.

__________________
Everything I need to know I learned through Googling.

The recollection is correct. Originally it was called MESUR Pathfinder. The MESUR (I've found a link to some hard data on MESUR) part of the name referred to a planned mission called Mars Environmental SURVey, a network of landers that was to use the "bouncing ballon" method of re-entry.

The attached rover was also a testbed for a system of remote operation that had been developed since the early 80's. In the end it stole the show from the lander and led to the current MER project.

Ironically NASA decided that the 1$ Billion price tag for the MESUR program was too much and canned the project. Fortunately planning for the testbed was far too advanced for it to also be canned.

I'd also agree that sending multiple MER style Rovers would be the optimum solution. However the prime need is, at least in my reading, for some sort of coordinated network to cover a wide area of the Martian surface to get information not just from one or two locations, but dozens.

Ironically this is what MESUR would have provided had it gone ahead.

What I am suggesting is that perhaps some consideration might be given to looking over the one result of the MESUR program and rather than simply abandon the technology (& concept) make full use of it to get the information in fewer launches than if a rover (or two) was sent at each launch opportunity.

There is a problem in this solution. MER, just as any other Mars mission, was fully optimized for its specific type of Mars opposition. Now, as we all recollect, the 2003 opposition was extremely close (duck! duck! duck!), which meant that with a "cheap" delta-2 rocket we could get it to Mars. Flying multiple Mars missions with identical hardware seems to be rather inefficient, if at all possible...

__________________
Our Moonshot: join the One Campaign.
please visit: www.one.org

Firstly, I do not advocate a full repeat of the MER mission, the key objectives outlined in the briefing document do not require such. Sending more rovers is optimum only in terms of the Media coverage it would generate. (I admit that this contradicts what I said earlier but I've had time to think since then).

What appears to be needed is a comprehensive measurement of selected Martian conditions (eg weather, solar radiation at surface). This could be better served by fixed stations spread over a wide part of the Martian surface.

The replication of a flight proven design concept such as Pathfinder would allow this to be done more expeditiously than if a new design was created, tested and then launced.

Series manufacture would also have the useful effect of lowering costs.

Further, it should be noted that a fixed payload design would also allow optimisation of the boosters to fit the conditions of the particular opposition.

Finally, in support of the above, consider the Surveyor series used during the lead up to Apollo. There were seven attempted landings with five successes all using the same design of spacecraft. The consistency in design and fit out allowed the results to be compared in a way that the current 'new lander for each opportunity' approach does not.

(Multiple edits to reflect further thought on the concept)

Would 'micro-landers' be an option for such a task? If you could keep one below 200 kilos (incl. EDL technology) you can send a few of these in a single Delta-2 launch. I don't know what the requirements for these probes are but I guess they can be made pretty 'low-profile'. The solar-array is likely to be the toughest component to miniaturize.

__________________
Our Moonshot: join the One Campaign.
please visit: www.one.org

I'm not sure what the minimum size for a solar panel array at Mars to provide power for both experiments & communications would be.

Small 'bounce landers' might be required to use batteries, which would seriously cut into surface lifespan.

As to the size/weight of the landers, Pathfinder, less the rover worked out at 264 kilos and Pathfinder in my opinion would make a good basis for a 'network lander' concept.

Interestingly 'basic' hardlanders seem to have a long history, one of the precursors to Viking was a 'watermelon size' probe with a mast mounted camera (see here), which would have used balsawood to cushion the impact much in the manner of Ranger 3 to 5.

A certain mission from the Planetary Society should make people rethink this micro-nonsense.

Stop all probe construction--focus on better lift--then put some nuclear-electric rovers up there capable of circumnavigating the Martian disk.

No more toys.