BigDog

Imagine this thing with a pancam on the front and a low gain antenna at the rear....
It's a Martian Lama!

It's been done!

There was the Sidewinder US Army transport back in the 2060s, and NASA also invested in bipedal walking technology a few years ago. There were problems with both - in the case of the Sidewinder it was particularly when triumphal music was played! Still, at least it was a good contract from the Army's point of view - there were no strings attached.

"I think you'll find this present a valuable addition to our modern lifestyle. They're Techno-trousers, ex-NASA, fantastic for walkies."

Bob Shaw

Hello all:

After years of lurking and reading all of your postings on a daily basis, I thought I'd join the forum and contribute where I am able as a non-technical armchair enthusiast.

The recent announcement that Opportunity may well be headed to Ithaca/Endeavour has reminded me of a topic that I have long wanted to get UMSF members' views on - one which doesn't appear to have been discused at any length before:

Do you think it would make sense for NASA to build a fleet (let's say between 4 and 8) of _slightly_-improved MER "Mark 2" rovers (or "MER 2.0" if you prefer), and send them off to Mars at a rate of 1 or 2 per opposition?

Here are my own top 3 reasons why NASA might want to commit to building a corps of "MER Mk.2 " rovers:

1. Familiarity: After more than 3000 sols of experience, including more than 20 km of driving, 100,000+ photos, 3x2 winters and 1x2 severe dust storms, the MER rovers have gone through a phenomenenal amount of road testing. In addition to this, there is also the 4.5 years of hands-experience with the test units at JPL. Perhaps of equal importance, there is also a large group of people with extensive direct experience in working with the MERs.

2. Performance: These rovers have turned out to be wonderfully well engineered (and operated). While Spirit is certainly showing its age, and Opportunity could suffer some sort of catstrophic fault in the near future, both of these rovers have now been producing useful science more than 18 times longer than their original intended mission. I think it would be reasonable - conservative, even - to expect a new MER built to _exactly_ the same design to travel at least 5 kilometers, and to survive at least 1 to 1.5 Martian years (i.e. until a second dust storm and/or winter season.)

This is not to say the rovers are perfect as is. They're not. But we now have a very good understanding of their limitations and design drawbacks. In fact, I think it's our deep understanding of the current MERs' imperfections that makes the idea of an incrementally-improved MER Mk.2 so attractive to my way of thinking - we have a very good idea of what really needs fixing. Moreover, it's my perception (as a non-engineer), that most or all of the crucial vulnerabilities in the design of the MER could be addressed with incremental changes to individal parts of the rover, rather than through a overall redesign.

3. Cost: This is the least certain of the advantages, but my assumption is that if 90% of a MER Mk.2 rover is identical to the MER units currently operating on Mars, then a lot of the neccessary modelling, designing and testing work (and expense) has already been done. And if building Opportunity as a second rover cost only half again as much as building Spirit alone, then I'm assuming there could be even greater per-rover cost savings from building 4, 6 or 8 MER Mk.2 rovers at once.

I'm very interested to know what you all think!

Two main reasons why not.

1) There are not that many safe places that are scientifically interesting to land MER style landers

2) Are you paying?


Doug

Whups.

I see now that there WAS quite a discussion at the end of 2005 about sending a third MER to Mars here:


Mer 3 Possibility?


I wonder if people's conclusions from then still hold, or whether the continued survival (and scientific activity) of the rovers for a further three years has changed the cost-benefit equation appreciably?

Regarding your the first of your two responses, Doug, my understanding is that the list of potential sites back for Spirit and Opportunity were quite limited (Athabaska Vallis was the only other real contender, if I remember correctly). But I wonder whether a new call for potential sites might come up with a longer list of good candidates, if the capabilities of the MERs were redefined in terms of what the MERs have since shown themselves to be capable of. That is, rather than looking for sites appropriate for rovers that have a 90-sol lifetime and a 600-metre range, a new site selection process would be looking for sites appropriate for rovers with a ~1000 sol lifetime, and a 5-or-better km range.

I think HiRISE data would probably reduce the number of candidate landing sites. It's not about rover longevity. MER still can not be guarenteed to do a 'drive to' with a range of, say, 6km and an ellipse 10x that distance long. It's about safe, interesting landing sites - and for MER, there are not very many.

As Mike Caplinger has said several times, MER heritage is in the box level...the pieces of the machine. Navcam and Hazcam and going on MSL. Various other components might find use in other vehicles.

And even if we had 100 brilliant, safe landing sites for the MER design - the question still remains..

Who's paying?


Doug

Several of us have argued on this forum that flying a series of medium sized rovers over a period of a decade should be done before flying a Mars sample return. Flying near duplicate rovers would fit within the expected funding profile (while MSR would not), extend our knowledge of the surface, and allow a better selection of the one site to get samples for return from (as well as pre-cache a collection of samples gathered over 1-n years on the surface).

The proposed mid-sized rover for 2016 which is currently on the roadmap would meet all these goals for the first site.

Simon--Welcome and nice to have your contributions to the forum. I like your idea, have had it myself, but the hard reality is Doug's question of "Who's paying". Space budgets are really hurting everywhere, so while multiple MER's seems very attractive, mission selection is ultra competative. Maybe we can get Bill Gates, or someone with deep pockets to help support Mars exploration.
-Floyd

Hi Floyd:

Thanks - it's good to be here!

Doug's question is a good one, I agree. So in an attempt to respond, I'll pitch two possible scenarios about who might want to pay for MER Mk.2s. I'll let you tell me how far-fetched these possbilities are...

Scenario 1: Cheap MER Mk.2s make it possible for little space nations to fund a Mars rover mission (a.k.a. "reduced costs opens up a larger potential market"...)

If I think happy thoughts, I could just about imagine an agreement through which the US agrees to build a fleet of MER Mk.2 rovers (lots of space jobs), a good proportion of which are funded by "small" space nations like my own (Canada) that don't have the budgets to pay for an original mission of their own. Others possible co-funders might be the UK, other ESA countries, or India. Let's assume that with the cost discounts that come from "mass production," even Canada could find its way to funding a rover of its own. I'll get really creative and surmise that ESA might even pay in-kind if they have rockets with a bit more capacity than the Delta 2 (which means space jobs for them too).

What would a country like Canada get out of this? Well, the Canadian Space Agency would get to be the lead agency on an honest-to-god Mars rover mission which would otherwise have been utterly unaffordable for them. Canadians would get to see "their" rover on Mars, and I think we all recognize how much the prospect of national prestige can influence space exploration budgets (as an aside, I think CSA might want its rover to go to Athabaska Vallis, given the namesake for this bit of Mars is located in Alberta...). And it's not unreasonable to think that the "little" space agencies like CSA could also contribute modest instrumentation packages to some or all of the other rovers as well. In line with the Canadian role on Phoenix, maybe a number of the MER Mk.2 rovers could incorporate little Canadian met packages. The Brits could have another instrument on a number of the rovers, as might the Indians, etc. So these little space powers would get to be the prime agency for their one rover, and could play a subsidiary role on a number of other countries' rovers.

As a Canadian, would I be willing to pay tax dollars for be a part of this? Oh yes! And I think a large number of my compatriots would too - at least during good economic times.

So what's in it for the Americans? I assume they would be able to pick and choose what missions they wanted to lead, and which to participate in. And which to avoid. Which is to say, the Americans would likely be able to lead those missions with the best science opportunities / lowest risks / nicest scenery or any desired combination of these. In doing so, the Americans would get the benefits of lower per unit rover costs, even if they didn't actually pay for more than half of them themselves. The Americans would get most of the jobs for building the rovers, and I assume JPL would still the natural place for mission operations and overall coordination. Plus there's the very real prestige of developing the Model T of extraplanetary rovers! Maybe the Canadians/British/Indians would be controlling individual rovers, but it would always be clear who fundamentally made these missions possible...


Scenario 2: NASA plays it safe following the morale-bruising failure of a more innovative misison. This scenario is a lot less cheery, but I believe there have already been instances where NASA has reacted to the failure of an expensive, innovative mission by following up with a cheaper, lower-risk mission, that in addition to its science objectives aims to restore public confidence in the agency's space exploration prowess. The MER Mk.2s would seem to fit the bill for a relatively safe, popular mission.

Those are my thoughts, but I imagine there are some even better scenarios regarding who might want to pay and why...

(BTW, I apologize if these scenarios are a little heavy heavy on "political" considerations - I trust I haven't crossed the line here.)