[meteorite-list] Phoenix Lander
Mark Ford
mark.ford at ssl.gb.com
Wed Jun 4 06:15:33 EDT 2008
Hi Sterling et al.,
Naturally you have a valid point, and they must have their reasons, but
surely, figuring out how to use the arm on Mars should surely all have
been done on Earth sims many many times already? - as for having to
write blocks of code and test it to make it move (Christ almighty, life
really doesn't have to be that difficult y'know!), yes naturally there
are the mars variables to worry about and the odd glitch etc, but just
seems strange that they are this far in with relatively little to show
(so far) that's all. But yes, hopefully I guess the diligence will pay
off..
>>Remember, this is a remake mounted on an unused backup
>>spacecraft, a hybrid, a kludge, an Apple running Windows which
>>is emulating Unix (not literally, but you get the idea). You know
>>how much data the Phoenix can hold overnight (if it needs to)?
>>Yes, friends -- 14 Megabytes
Yes but it is hardly a cobble together from radio shack we are talking
fully tested custom made, top quality space hardware here! And it runs
a pretty good Linux O/S deriv. I recall, which has no doubt even been
tested too.
(Programmer gag - I can understand if it is a Linux type OS they would
need to rewrite a quick 'Mars driver', coz the one they have doesn't
quite work...)
14 meg?! Actually that's massive considering most engineering data only
needs to be simple binary text, you should see what the early stuff had
to work with !!
I did chuckle however when they announced the fact that the soil is
sticking to the digger/scoop much more than they thought it would, -
errm what exactly where they expecting in the martian high arctic during
summer ? a nice dry sand that slides off the scoop like a dream?? Does
anyone actually remember the moon? Lol. - I jest of course
Mark
-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
Sterling K. Webb
Sent: 04 June 2008 04:30
To: francisgraham at rocketmail.com; meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] Phoenix Lander
Hi,
I note that all your examples involve return and the possibility
of a rapid exit. We want a robot to last and to perform for as
long as possible; it can't dash home and we wouldn't want it to.
Operating a robot by telepresence over a long light-time delay
is chancy. Phoenix has already had "problems" with radio
transmission and various other minor glitches.
I recommend reading the following piece about the way the
command structure of the Phoenix "robot" works:
http://phoenix.lpl.arizona.edu/blogsPost.php?bID=202
As you can see, it's not like pushing a big button on the Robot
Control Panel. Things are done by writing blocks of VML2
code to accomplish a specific task, testing them, sending them,
etc. As the SSI Co-Investigator says, "Frankly, any day with
a tomorrow is a good day on Mars."
Remember, this is a remake mounted on an unused backup
spacecraft, a hybrid, a kludge, an Apple running Windows which
is emulating Unix (not literally, but you get the idea). You know
how much data the Phoenix can hold overnight (if it needs to)?
Yes, friends -- 14 Megabytes. How big is the flash card in your
digital camera?
I think it's doing a wonderful job. Go slow. Test every foothold
before you put your weight on it. Look before you leap. Small steps,
small steps...
Sterling K. Webb
------------------------------------------------------------------------
---------
----- Original Message -----
From: "Francis Graham" <francisgraham at rocketmail.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Tuesday, June 03, 2008 9:35 PM
Subject: [meteorite-list] Phoenix Lander
Dear List
Mark Ford has a point. In the Apollo Lunar Missions, right away as
soon as
they emerged from the LM, the astronauts obtained a basket of moon rocks
and
sent it up to the LM. The reasoning was, if something went amiss, and
they
had to leave the lunar surface soon after landing, they would not return
empty-handed. This was called a "contingency sample".
The argument also applies to unmanned missions. Phoenix might have had
a
provision for an immediate contingency analysis designed in to its
program,
but, at risk of peril, did not, and waited a week.
Nonetheless it is a good idea to do contingency sampling. It might be
also
a good idea for a future Mars sample return mission to obtain an
immediate
contingency sample. If things go wrong, and the scoop arm later
malfunctions
while picking around for interesting stuff, or some such, at least they
can
blast the hurried small contingency sample off Mars and back to Earth.
One can apply this also to astronomy. One might collect what data one
can,
even low grade, right away, in case it clouds up. Then do careful
instrument
tweaking if clouds stay away. In meteorite collecting, one can grab a
few
random samples around the crater ejecta and then, if the situation
remains
pleasant, seek out better samples elsewhere. Seems like a smart idea.
There is a host of practical problems to which this idea can be
applied,
where time=increased chance of difficulties.
Francis Graham
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