Rollin' Rollin' Rollin'...Get That Rover Rollin' !!

Henry Spencer wrote:
The MERs have some, I think. As did Mars Pathfinder and Sojourner.
They're a bit limited because you can't turn them *off* when things
get too warm, so you can't be too enthusiastic with them.

Yes and no. Pioneers 10 and 11, if I recall correctly, had things
like venetian blinds which opened or closed depending on temperature.
I believe they used no electronics, but just bimetallic strips.

Something like that ought to work even better on Mars than in vacuum.

They've been used on quite a few things, but without much publicity.
I don't *think* Apollo used any -- running on fuel cells, it had
plenty of power even at night -- but I believe there were some in
the surface-experiment packages, including Apollo 11's seismometer.

Didn't all the surface-experiment packages use RTGs for power? If
not, why was there concern over plutonium in Apollo 13s LEM, which
crashed into the Pacific? Why else would there have been plutonium
in the LEM?
--
Keith F. Lynch - - http://keithlynch.net/
I always welcome replies to my e-mail, postings, and web pages, but
unsolicited bulk e-mail (spam) is not acceptable. Please do not send me
HTML, "rich text," or attachments, as all such email is discarded unread.

In article ,
Keith F. Lynch wrote:
[RHUs are] a bit limited because you can't turn them *off* when things
get too warm, so you can't be too enthusiastic with them.

Yes and no. Pioneers 10 and 11, if I recall correctly, had things
like venetian blinds which opened or closed depending on temperature.
I believe they used no electronics, but just bimetallic strips.

They're called louvers. They work, but people are a bit reluctant to
trust them because they do have moving parts, and in theory can stick.

Something like that ought to work even better on Mars than in vacuum.

It's trickier on Mars, actually. You'd like to keep out dust, there's
more worry about sticking in the presence of dust, and louvers typically
don't seal well enough to give really *good* insulation in an atmosphere.
(Air flow can carry off substantial amounts of heat through quite narrow
slits.)

I don't *think* Apollo used any -- running on fuel cells, it had
plenty of power even at night -- but I believe there were some in
the surface-experiment packages, including Apollo 11's seismometer.

Didn't all the surface-experiment packages use RTGs for power?

All except the Apollo 11 one, but I was treating RTGs as a separate issue.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

LooseChanj wrote:
On or about Fri, 9 Jan 2004 23:32:57 +0800, Neil Gerace made the sensational claim that:

"Chosp" wrote in message
news:VMqLb.35481$i55.12352@fed1read06...

"Diane Wilson" wrote in message
link.net...

In article ,
om@our_blessed_lady_mary_of_the_holy_NASA_rese arch_facility.org says...

On Wed, 07 Jan 2004 13:48:03 GMT, Diane Wilson
wrote:


Then it's pretty poor planning to have only one sun available.
I mean, what if it goes out?

...Pat, Diane thinks she's you, now :-P

Nonsense. I'm Jim Oberg, just like everyone else.

Diane

That's good. Very good.

I'M Spartacus!



Bond. James Bond.

I'm Tigger. That's T-I-double-guh-er.
--
Tim Demko
http://www.d.umn.edu/~tdemko

"Andrew Gray" wrote in message
. ..
In article , Derek Lyons wrote:

kill them due to lack of power. (Some observations can take as much
as 12-24 hours, with a predicted life of 90 days that means they need
to get moving as soon as reasonably possible.)

Is that 90 days or 90 sols, BTW?

It's 90 sols, actually.

But, that's only a nominal mission target, with buffers
built-in to do all the intended science. Chances are
the rovers will last 180 days or longer. So far the
thermal environment has been better than planned
for.

Bruce