Lost in Space

"Jorge R. Frank" wrote:

A more likely answer is that if we ever send a manned craft to a
deep-space target, it would likely be preceded by lots of unmanned
craft. Look at Mars for example. When we finally get there, we will
have a full orbital communications network, a Martian GPS

I agree there will be robotic assets, but I don't think they will be as
extensive as you paint it. A Martian GPS (MPS?) is a nice luxury but will
likely be one of the first things axed when overruns start occurring on the
manned side of the mission.

The sad part is that, despite the limited utility of a M-GPS type of
system, somebody will probably propose one and millions will be wasted
on developing it.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"dean" wrote in message
news:2006112309332116807-robodean@gmailcom...
snip

I was more hung up about the loss of communication with long term
missions. It is conceivable that sometime, in a few decades, we may start
undertaking long range space travel. I was just playing a thought
experiment. What if? What if a spaceship went off to Europa and all its
communication gear went dead. What would or could happen.
But of course, at least for the very near future, you are totally right.


I don't think we have a radar or visual track on deep space probes. I think
without an active communication on the probe, we would loose it completely,
i.e. it would become invisible to us.

Danny Dot
www.mobbinggonemad.org

wrote in message
oups.com...

snip


Consider the Mars Observer back in 1992. This unmanned probe abruptly
stopped communicating. There was a plan to point Hubble at Mars to
take a look. Although Hubble could not see the probe, it would be able
to see the glare as the probe fired up its engines to slide into Mars
orbit.

Are you sure about this? I wouldn't think the "glare" or those small
engines could be seen by Hubble.

Danny Dot
www.mobbinggonemad.org

snip

Danny Dot wrote:
Are you sure about this? I wouldn't think the "glare" or those small
engines could be seen by Hubble.

Hmm, I can't seem to find anything online to confirm this.

On the other hand, the planet chart at www.heavens-above.com seems to
indicate that there was about a 35 degree angle between Mars and the
Sun from Earth on 21 Aug 1993. Hubble's normal cutoff is around 50
degrees (I can only find one reference to this). Which correlates with
what I heard at the time which was that using Hubble was technically
possible but not worth the extreme risk, given that the resulting
information would likely not tell us how to rescue the probe.

As for picking up the engine glare, I suspect that any such
hypothetical observations would be a difference operation. Take a
grossly over-exposed shot of Mars. Take a grossly over-exposed shot of
Mars + Mars Observer. Mathematically subtract the two images. Look
for non-random differences. One advantage of this sort of observations
is that one is just counting photons, not trying to build a sharp
image. So the uncorrected flaw in Hubble's mirror would not have made
any significant difference.

Another thing that would help is that one would be looking for the
characteristic wavelength generated by the monomethyl hydrazine fuel in
Mars Observer's engines. I've no idea what the spectra of burning
monomethyl hydrazine is, but Hubble has got an extensive set of filters
which could be juggled to get rid of as much background light as
possible.

wrote in message
ups.com...
Danny Dot wrote:
Are you sure about this? I wouldn't think the "glare" or those small
engines could be seen by Hubble.

Hmm, I can't seem to find anything online to confirm this.

On the other hand, the planet chart at www.heavens-above.com seems to
indicate that there was about a 35 degree angle between Mars and the
Sun from Earth on 21 Aug 1993. Hubble's normal cutoff is around 50
degrees (I can only find one reference to this). Which correlates with
what I heard at the time which was that using Hubble was technically
possible but not worth the extreme risk, given that the resulting
information would likely not tell us how to rescue the probe.

As for picking up the engine glare, I suspect that any such
hypothetical observations would be a difference operation. Take a
grossly over-exposed shot of Mars. Take a grossly over-exposed shot of
Mars + Mars Observer. Mathematically subtract the two images. Look
for non-random differences. One advantage of this sort of observations
is that one is just counting photons, not trying to build a sharp
image. So the uncorrected flaw in Hubble's mirror would not have made
any significant difference.

Another thing that would help is that one would be looking for the
characteristic wavelength generated by the monomethyl hydrazine fuel in
Mars Observer's engines. I've no idea what the spectra of burning
monomethyl hydrazine is, but Hubble has got an extensive set of filters
which could be juggled to get rid of as much background light as
possible.


Nice post, Thanks.

I am not going to say I know Hubble could not have seen the rocket plume.

Danny Dot
www.mobbinggonemad.org