NASA Announces Public Meeting for Proposed Mars Mission Options

[Guest_AlexBlackwell_*]

NASA Announces Public Meeting for Proposed Mars Mission
MEDIA ADVISORY: M06-154
October 4, 2006

[gndonald]

I see NASA is still afraid to show the RTG power supply on the MSL rover. Here's hoping that the Anti-Nuclear crowd don't 'smoke' them into chosing Solar Panels for this one.

[Mariner9]

Yes, I also noticed a mention of the mission using either an RTG or solar panel power. I have trouble imagining that JPL is still pondering that move this late into the design.... so have to wonder if that is also a political move on their part to give the impression that if they are indeed going with RTG, that the decision was carefully weighed from the engineering standpoint and they didn't just jump to that conclusion too quickly.

The sucess of the MERs might be playing a part in all this. The conventional engineering wisdom before the mission landed was that solar panels would loose effectiveness over time as the dust collected. At 2.5 years and going strong, MER is putting that concern to rest. So even if using an RTG is still a better choice for MSL, it gives ammunition to the anti-nuke crowd to point at MER and say that solar can do the job.

I hope they go with an RTG... because we all know that in spite of the improvement in solar cells over the last 20 years, many of the outer planets missions still need nuclear power. Loosing this one because of politics would bode ill for future missions.

[punkboi]

I see NASA is still afraid to show the RTG power supply on the MSL rover. Here's hoping that the Anti-Nuclear crowd don't 'smoke' them into chosing Solar Panels for this one.

They won't. They couldn't even 'smoke' NASA into not launching Galileo, Cassini and New Horizons

[helvick]

At 2.5 years and going strong, MER is putting that concern to rest. So even if using an RTG is still a better choice for MSL, it gives ammunition to the anti-nuke crowd to point at MER and say that solar can do the job.

I'm certain that they are being vague in order to avoid drawing unnecessary attention to it but the argument that the MER's have proven that solar panels are good enough doesn't hold water for MSL. Speaking as UMSF.com's #1 Solar power fan I have to say that I'd be disgusted if Solar power is being seriously considered for MSL.

The MER's have been lucky. There have been no really bad dust storms since they landed. A single dust storm on a par with either of the 1977 storms that the Vikings lived through would have killed both MER's. To survive such a storm any rover needs approximately 5x margin of solar power generating capacity.

They are were also extremely tightly constrained in where they could be targeted. Spirit is only 12deg further south than Opportunity yet it is at the extreme edge of the survival zone for a MER type rover - and that was the case in it's first year of operation. Had it been even a few degrees further south it could not have survived its first winter.

Solar Panels are physically awkward and impose mobility constraints. Roving in canyon type terrain or even close in to cliffs that are badly oriented (ie that would block the sun) is just not an option.

I could go on.

[lyford]

From the release:

An alternative mission would be powered by solar arrays.

I would say that it would be an extremely alternate mission, and would be so constrained as to change MSL's abilities and mission. 75kg of science instruments, heavier rover with more mobility power draw, longer range... all would be at the mercy of an unpredictable power budget. I can almost imagine that MSL with solar would more resemble a crocodile having to bask in the sun just to get enough energy to make it through the day....

[mcaplinger]

I would say that it would be an extremely alternate mission, and would be so constrained as to change MSL's abilities and mission. 75kg of science instruments, heavier rover with more mobility power draw, longer range... all would be at the mercy of an unpredictable power budget.

Did anybody read the EIS? In my quick skim, they really didn't make this case as strongly as I thought they would, focusing mostly on the latitude restrictions that would come with solar. Frankly, if I read the EIS in isolation I might well conclude that they hadn't really justified needing the RTG.

[lyford]

I agree it's a rather bland presentation of the restrictions:

For the reasons discussed below, the solar powered rover for Alternative 2 would not be capable of operating over the full range of scientifically desireable landing site latitudes.

Touche!

Solar restricts the mission to 15 degrees N in the alternate- which is the only place on Mars giving the full power for a full Mars year. If you lower the power requirements, you can stretch that a bit, but they you have to give up some instruments or make the mission less than a Martian year...

I think they also should mention that the solar version looks like a house boat compared to the cool batmobile thermal regulators on the RTG model

(let me know if the inline images are too large to load for some with slow connections and i'll make them attachments)

[Mariner9]

I stand by my point that the anti-nuke crowd could easily use MER as an argument against going Nuclear.

I don't think it is a good argument, and would ultimately loose for all the reasons everyone has stated, but it is not a completely crazy argument either. Who said the rover HAD to go farther south or north? And does it HAVE to last more than a year? And so on and so on. Clearly you could do the mission with solar power, it would just be a lot less capable.

Keep in mind, these same folk argued that NASA had failed to consider making Cassini solar powered .... although I never did see any indication that the protesters had bothered to make even a back of the envelope study of their own to show that Cassini could get enough power from solar panels, or just how large and heavy those panels would need to be. But hey, not their job, right? They just complain, and NASA should spend millions proving their wild complaints to be invalid.


I think the point was made that the presentation was made to avoid drawing unecessary attention to the whole issue. I agree... and I hope it works. I don't see the anti-nuke folk suceeding (especially with the current administration in office) but I also don't want a nasty battle which would make any future use of RTGs that much harder.

[dvandorn]

The problem is, if you tell these people that you need the energy available from an RTG to accomplish the mission, they'll just use their circular logic to conclude that any mission which requires nuclear power isn't worth the risk. Period. End of story. Their argument becomes: If you can't do the mission without using plutonium, then the mission doesn't need to be flown. If you insist that it does, then you are knowingly exposing them to an almost certain death. They're looking for a reason to hate and fear you.

No amount of logic or reasoning will budge them from that position, because they are not operating from a rational position. They are irrational and driven entirely by fear -- fear engendered by people who want to use a mass of fearful people to further their own goals of acquiring and retaining some form of power.

Keeping people afraid in order to achieve power is the worst, most profoundly sick and perverted mindset in the entire panoply of the human psyche. It's also one of the most common perversions. If it were possible to alter human nature, this is the place I would start.

-the other Doug

[djellison]

The Anti's couldn't stop Pioneer, Voyager, Viking, Cassini, Galileo or NH....they won't stop MSL either.

Doug

[Jeff7]

I stand by my point that the anti-nuke crowd could easily use MER as an argument against going Nuclear.

Though let us not forget, the MERs do have some radioisotope heaters in them. Even for them, solar still isn't technically enough. Otherwise I guess they'd need bigger batteries to provide power to electric heaters, which means either larger solar panels are needed, or less science gets done.
So the anti-nuke extremists could probably even say that the MERs shouldn't ever have flown in their current form.

[Rakhir]

Nasa finally admits plutonium dangers

[helvick]

This is out of date, inaccurate and makes some claims that are unsubstantiated and improbable. If it were were worth picking apart I'd spend some time doing it but it's far too sloppy to warrant the effort.
But some quick points:
[1] This is old news - we debated this (Solar Power for probes beyond Jupiter) months back.
[2] The data referenced is grossly inaccurate, especially the damage caused by US launch failures that involved spacecraft with on board nuclear power.
[3] The implications that solar power was developed as a consequence of either those launch failures or some dudes speculative analysis of the effects of them is highly simplistic at best.
And I could go on.

Folks like the author of this piece really would be well advised to put their energy into having resources put towards the safe recovery and disposal of the RTG's used by the Former Soviet Union to power remote lighthouses. That stuff is much more likely to do bad things to people here on earth.

Harrumph.

[Jeff7]

Nasa finally admits plutonium dangers

The article cited something in “Aviation Week & Space Technology”:
"The U.S. space agency is already planning a solar-powered mission to study the atmosphere of Jupiter, and has looked at sending probes as deep into space as Neptune using only the Sun’s energy for spacecraft and instrument power…It is all but certain the next U.S. deep-space missions will be solar-powered."

To Neptune? Using solar power? To do what, run a 1MP digital camera and a transmitter?
If there are such efficient solar cells out there, where are they? Why are we in the consumer market stuck using cells that max out at around 13%?


Plutonium in space would be even less necessary if they'd get the Prometheus program going again.
Sure they'd use uranium, so some people would still complain, but it's not nearly as toxic, and it would allow for much more powerful spacecraft.