Beagle 2 again

Hi, is there any likelihood that the guidance could have been so far out
that the landau is actually in a completely different part of Mars?

Even if the lander died, it is a great pity that nobody spent the money to
at least send low rate telemetry during re entry, as the info would be
invlauable to all designing vehicles later on.

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
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Even if the lander died, it is a great pity that nobody spent the money to
at least send low rate telemetry during re entry, as the info would be
invlauable to all designing vehicles later on.

yeah, they followed nasa lead

Brian Gaff wrote:

Hi, is there any likelihood that the guidance could have been so far out
that the landau is actually in a completely different part of Mars?

Since Beagle 2 had no "guidance," I presume you are referring to the
navigational accuracy of Mars Express at the point it released the
Beagle 2 lander?

That said, the likelihood that Mars Express mission controllers
completely screwed up the navigation to the point that they actually
missed an entire hemisphere is, I would say, vanishingly small. MEx
controllers are confident of their release point, which, assuming
nominal post-release trajectory, would have resulted in a direct
ballistic entry of Beagle 2 and a landing/crash somewhere inside the
planned landing ellipse - this is fairly straightforward. There is,
however, a landing footprint stemming from the entry corridor outside of
which the Beagle 2 Project is certain that the probe would *not* survive.

--


Alex R. Blackwell
University of Hawaii

The Jodrell Bank radio observatory would have picked up any
transmissions from Beagle that were pointed in the general direction
of Earth (ie any transmissions from the correct Martian hemisphere).
If ME jettisoned the Beagle in such a way that the lander ended up in
the wrong hemisphere, it couldn't have landed, anyway.

However, in retrospect, those MER tones were a pretty good idea.



"Brian Gaff" wrote in message ...
Hi, is there any likelihood that the guidance could have been so far out
that the landau is actually in a completely different part of Mars?

Even if the lander died, it is a great pity that nobody spent the money to
at least send low rate telemetry during re entry, as the info would be
invlauable to all designing vehicles later on.

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________
__________________________________




---
Outgoing mail is certified Virus Free, so there!
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.561 / Virus Database: 353 - Release Date: 13/01/04

"Brian Gaff" wrote in message ...

Even if the lander died, it is a great pity that nobody spent the money to
at least send low rate telemetry during re entry, as the info would be
invlauable to all designing vehicles later on.

As I understand it, it's not really a matter of "they never bothered
to spend time/money" on data transmission during re-entry. The point
is (as is shown by a similar lack of real-time telemetry on more
expensive American and Russian landers) that it's not necessarily
worth the effort.

In order to transmit during re-entry you need to add so much hardware
and therefore weight to the lander that (considering the specific
hardware isn't going to be utilised once the spacecraft is on the
surface) it doesn't justify itself on the weight-to-usefullness scale.

(Specifically you need to add some kind of "window" to transmit
through during the re-entry phase which is also heat-resistant enough
to maintain the integrity of the spacecraft so you need something
kinda opaque and thick, which translates to opaque and *heavy*.)
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