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Posted by: Marcel Jul 21 2005, 12:07 PM

I wonder if a small RTG could help Phoenix through northern winter after its primairy mission (in order to keep it awake at minimum requirements for thermal and communication purposes), and what you'll think about that idea.

Posted by: Analyst Jul 21 2005, 01:03 PM

Sure it could. But it would cost a lot of money. Besides, launch is about two years away, the design is fixed, they are well in development and component testing.

No chance, forget it.

Posted by: Marcel Jul 21 2005, 01:21 PM

I understand that it would cost money. The question is how much.

The main two things that it would need is

1

Posted by: Marcel Jul 21 2005, 01:24 PM

Oops, sorry, did not finish yet:

It needs:

1 Space to integrate
2 A connection to the main bus.

Et voila.

But you're probably right, it's too late. The thing's allready built.

Posted by: djellison Jul 21 2005, 01:48 PM

No money ( PHX has already dropped the active entry iirc, because the money simply isnt there)

No volume - already a tight squeeze inside the payload - which is way way beyond PDR, and thus not changeable.

No mass - it'll be calculated to the last kg - the launch vehicle is probably undergoing manufacture already - A Delta II - which flavour I'm not sure.

I think people very very easily underestimate the complexity of spacecraft.

And lest we forget - we dont NEED months and months of extended mission. Take the full panorama, do the trenching, enjoy the LIDAR - job done.

It's not like an extra year would be usefull so we can drive 5km to a different area...and NO...we cant put wheels on it

Doug

Posted by: Marcel Jul 22 2005, 07:07 AM

I know exactly what you mean Doug. It was just an idea without me knowing much about the architecture of the lander itself. What was leading in the idea, is that an RTG is self sustaining: it doesn't need anything except a place (which is not available considering your reply) and a galvanic line to the bus (which shouldn't be a problem). The money however is always a "problem".

I'll forget about it.

Posted by: RNeuhaus Jul 22 2005, 10:14 PM

It would be interesting to know a bit more about the exotic source of energy RTG. I am ignorant of this and I would be appreciated if anyone can point any reference or any posting to describe the technicals details of that. So far I know that it would cost much and also weight and size. By how much?

Rodolfo

Posted by: Bob Shaw Jul 22 2005, 10:30 PM

Marcel:

Not just the money, but the fissile material - believe it or not, fuel for RTGs is in short supply, and the New Horizons Pluto (and beyond!) vehicle was under quite a lot of pressure at one point due to the inability to get the thing fully topped off...

Interestingly, there are radionucleide heaters in the MER rovers, and even aboard Pathfinder - and there were tons of the things aboard Mars-96, now spread over the Andes... ...well, not actually tons, but it does give one pause for thought when the 'no-nukes' brigade pipe up!

Bob Shaw

Posted by: deglr6328 Jul 22 2005, 11:49 PM

Check out the Wikipedia page. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator I think its quite nice (since I contributed quite a bit to it ).

Posted by: RNeuhaus Jul 23 2005, 03:06 PM

deglr6328
Very good encyclopedia. Very readable.

Rodolfo