why is the mars rover's lifespan 90 days

On Sat, 10 Jan 2004 00:20:52 -0800, Rick wrote:

"David Knisely" wrote in message ...

is now. If the rover was RTG powered (ie: nuclear "batteries"), the power
would not be an issue, but such power generators are expensive, heavy, and not
popular with some environmentalists.

Good grief, it's MARS for chrissakes. Would the radiation damage
the planet's native flora and fauna??

Mars could conceivably have simple life. Using a nuclear power source
would be a serious contamination.

Using them in space, of course, is not. There's plenty of radiation going
about already.


--
- Mike

Remove 'spambegone.net' and reverse to send e-mail.

Rick wrote:

Good grief, it's MARS for chrissakes. Would the radiation damage
the planet's native flora and fauna??

No, but some of the more radical environmentalists worry (needlessly actually)
about the effects here of a launch accident releasing the Plutonium Oxide used
to generate the electricity in an RTG. This has caused some resistance to
their use, even though NASA has properly addressed these concerns in the RTG
design (one even survived a launch accident and was recovered and re-used on
another mission). However, again, RTGs are heavy and expensive (much moreso
than solar panels and batteries), so for these light direct-entry probes, we
will probably see solar power being used for the foreseeable future. Clear
skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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david posted:

What a wonderfully crass , anally generated, truly American attitude!

It isn't American at all. Its just one which is generated through a lack of
knowledge and frustration at the reaction of some environmentalists to things
which are not a significant threat to the environment. As such, it can be
modified by addressing the facts in a civil manner, rather than merely labling
things as being an "anally generated attitude" of one country or another.
Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
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Rick posted:

Indeed. In fact the orbiter in the current mission is powered with
2.7g of plutonium chloride..

No, the current orbiters are all solar powered. Some radioactive materials
might be used to provide warmth to some of the electronics, but the power for
all the orbiters is currently solar (with battery backup for when the
spacecraft is in the planet's shadow). Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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* Attend the 11th Annual NEBRASKA STAR PARTY *
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* http://www.NebraskaStarParty.org *
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If you did some research into upcoming missions, you'd see that NASA
has a large nuclear-powered rover on the board. Still, not enough
radiation escapes to make it dangerous. Nor does it on a
nuclear-powered ship, etc, etc.

Did anyone else but me read about and see what JPL did to try to keep foreign
materials from earth off of the rover during construction of it? Including
bacterial, viral, and another earth contaminates.
Of course they couldn`t make sure the thing is totally clean. They made a huge
effort to make sure anyting from earth did not contaminate Mars.
Dan.

Dan How long do you think the Earth's bacteria would last on Mars?
Bert

"G=EMC^2 Glazier" wrote in message
...
Dan How long do you think the Earth's bacteria would last on Mars?
Bert

"Earth microbes on the moon"
"Space historians will recall that the journey to the stars has more than
one life form on its passenger list: the names of a dozen Apollo astronauts
who walked on the moon and one inadvertent stowaway, a common bacteria,
Streptococcus mitis, the only known survivor of unprotected space travel. As
Marshall astronomers and biologists met recently to discuss biological
limits to life on Earth, the question of how an Earth bacteria could survive
in a vacuum without nutrients, water and radiation protection was less
speculative than might first be imagined. A little more than a month before
the forthcoming millennium celebration, NASA will mark without fanfare the
thirty year anniversary of documenting a microbe's first successful journey
from Earth."
"Although the space-faring microbe was described in a 1970 Newsweek article,
along with features in Sky and Telescope and Aviation Week and Space
Technology, the significance of a living organism surviving for nearly three
years in the harsh lunar environment may only now be placed in perspective,
after three decades of the biological revolution in understanding life and
its favored conditions."
http://science.nasa.gov/newhome/head...m#anchor179666

"David Knisely" wrote in message
...

No, but some of the more radical environmentalists worry (needlessly
actually)
about the effects here of a launch accident releasing the Plutonium Oxide
used
to generate the electricity in an RTG. This has caused some resistance to
their use, even though NASA has properly addressed these concerns in the
RTG
design (one even survived a launch accident and was recovered and re-used
on
another mission). However, again, RTGs are heavy and expensive (much
moreso
than solar panels and batteries), so for these light direct-entry probes,
we
will probably see solar power being used for the foreseeable future.
Clear
skies to you.

Why not launch a probe that has nothing but generators then? Have it land,
and then aim for all other probes to land within proximity of it. A sort of
Martian Exxon station? While I am on this, why not dump the high gain
antenna and have a series of probes between here and there to act as relays?
Several less powerful transmitter/receivers that can act as a grid, using
less power and ensuring great reliability?

BV.
www.iheartmypond.com

BV wrote:

Why not launch a probe that has nothing but generators then?

Same problems: the environmentalists, the cost, and the weight. If you want a
probe light or mobile and less expensive, something has to give. In this
case, its an RTG. They are heavy and they are expensive. If you want to cut
costs and weight, you can use solar power at Mars. Its not a perfect
solution, but, as Pathfinder (and now Spirit) has shown it works.

Have it land,
and then aim for all other probes to land within proximity of it.

A new problem: rendezvous. What happens if the launch of the generators
fails? Its still better to have the power systems sent with each probe.

While I am on this, why not dump the high gain
antenna and have a series of probes between here and there to act as relays?

Why? The high-gain antennas on the two Viking landers and Pathfinder worked
OK, and the one on Spirit also seems to be working quite well. We already
have two or three relays in orbit right now (Mars Global Surveyor, Mars
Odyssey, and Mars Express) for times when the Earth is not well placed for
direct contact.

Several less powerful transmitter/receivers that can act as a grid, using
less power and ensuring great reliability?

The communications gear is probably not the dominant power drain. Heating the
electronics, running the instruments, and supplying power for the motors
probably expends more current that the transmitter. The rover probably will
work a little past its design lifetime. The next one will probably use an
RTG, as the rover will be nearly the size of a small van and will probably
last for at least a year. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

On Fri, 16 Jan 2004 17:00:50 -0500, BenignVanilla wrote:


Why not launch a probe that has nothing but generators then? Have it land,
and then aim for all other probes to land within proximity of it. A sort
of Martian Exxon station? While I am on this, why not dump the high gain
antenna and have a series of probes between here and there to act as
relays? Several less powerful transmitter/receivers that can act as a
grid, using less power and ensuring great reliability?

Because it has potential.