Opportunity has landed

Peter Stickney wrote:

Airbags are 3 for 4, aren't thay, I seem to recall that Beagle 2 was
an airbagger. And we don't know just when/where it failed, yet.


Oh...that thing... how quickly one forgets _that_ thing.
Well, whatever it was, it has no right being on the same planet as
wonderful, and freedom-loving, American probes.
When the time comes, the little embarrassment must be hustled back to
Earth, or simply melted down for scrap metal so as not to contaminate
the environment of _our_ planet!
Maybe its remains could be used for a novelty ashtray or something.
God's judgment is plain in regards to Mars...His Divine Will has seen
fit to allow _only_ American probes to its surface to work...it is
apparent that he wishes the United States to claim the planet as part of
our Manifest Destiny!
In much the same way, He cannot be blamed for the unfortunate fact that
there are Arabs living on top of _our_ oil.
WHO are WE to DENY the WILL of GOD? ;-)

Pat

Brett Buck wrote in message . com...
Well, at some point in the near future, precision landing may be
needed - to follow up on previous discoveries, go to very specific
sites, etc. Unless they either get very much more competent rovers, that
means that it will have to be powered landers with high-accuracy
terminal guidance.

Actually, if you have a big, "fast", RTG powered rover you
can land in the safest spot (with airbags) and simply drive
to where you want. Reasonably achievable speeds for
Martian rovers in the near future could easily be in the km
per day category. And with a rover that lasted years
(Viking lander 1 lasted almost 6 years) you easily end up
with a range of hundreds to thousands of kilometers.

In article ,
Christopher M. Jones wrote:
Well, at some point in the near future, precision landing may be
needed - to follow up on previous discoveries, go to very specific
sites, etc. Unless they either get very much more competent rovers, that
means that it will have to be powered landers with high-accuracy
terminal guidance.

Actually, if you have a big, "fast", RTG powered rover you
can land in the safest spot (with airbags) and simply drive
to where you want.

Unfortunately, "safest" doesn't necessarily translate to "safe". The
airbag system doesn't *guarantee* a safe landing; a sharp rock could be
curtains for an airbag lander. You are better off doing a rocket landing
with a scanning lidar for finding a flat spot and flying to it.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

yes, like a combination skydive and bungee jump with rockets and a well
timed pair of scissors.

I used to skydive, and once saw ground rush at about 900 feet. I needed no
encouragement to find my ripcord and was glad i had peed before the jump.
Ground looks like it is a hammer coming at you. I was only going 120 mph,
and opened over 500, opportunity was going 140-150 and "opened at less than
30 feet (from the sounds of it, much less) and then immediately cut away!

that would be a heck of a carnival ride!



"RDG" wrote in message ...
Hell of a ride for a human crew! :-)

I can just see the carnival attractions now....

well, we could be picky and say American airbag systems are 3 for 3 (in fact
i think someone at JPL said that this morning)

but a more precise and useful thing to say is that the chute/rockets/airbag
trio is 3 for 3. Beagle did not have retro rockets i think.

there are limitations because of atmosphere depth, but i suspect they could
be gotten around. with rover mobility, accuracy becomes less a problem.

the key question is, if you have a delivery system with such a record, (and
even though the powered landers are 2 for 3, there were rocks very very
close by that could have wrecked them, and we were just blindly lucky we
didn't hit them) why would you spend a lot of time and money developing a
new system and risk projects on such untested devices?


"Peter Stickney" wrote in message
...
In article ,
Pat Flannery writes:


wrote:

Neil Gerace wrote on Sun, 25 Jan 2004 13:11:06
+0800:
:NG Strong signal, still rolling around on the surface though

Rolling along like the Energizer rabbit, it seems.

The inflatable landing bags seemed pretty wild-man crazy when they first
tried them on Pathfinder...but they've worked 3 for 3 now, and we have
an apparently quite reliable means of putting payloads on the surface of
Mars- combined with the probe design and whole landing technique, we now
have a great "Basic Bus" ability to get payloads to the Martian surface
with reliability...now if _I_ were deciding how things go from here...we
freeze the design for the landers, add different payloads, and go with
the Delta IIs for a while, then start stacking them in multiples on
Delta IV's or Atlas V's...lets put down a _whole gridwork_ of probes on
Mars; either using RTGs or trainable solar panels, and have a look at
this place say ten or twenty degrees of latitude by longitude at a time!
And MAKE SURE that that what's-his-name in the American flag shirt and
broom takes good care of them, and brings both to all future landings.
I'm not superstitious ...but I do remember Apollo 13...

Airbags are 3 for 4, aren't thay, I seem to recall that Beagle 2 was
an airbagger. And we don't know just when/where it failed, yet.

Otherwise, it seems like an Idea.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

On Sun, 25 Jan 2004 21:56:08 GMT, "bob"
wrote:

that would be a heck of a carnival ride!

....One that no doubt Disney would charge extra for even if you bought
the "E" ticket.

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

"bob" wrote in message
m...
opportunity was going 140-150 and "opened at less than
30 feet (from the sounds of it, much less) and then immediately cut away!

Note that it *wasn't* going "140-150" at the time it was cut away.

of course not. but it was going 140-150 just before the rockets fired off. a
high tech bungee jump
the low G's recorded suggest to me that the thing came to a stop a little
lower than expected.
Spirit was less than 30 feet (anyone remember how much lower?) when it cut
loos I will be interested to hear how low this one was. I wager under 15
feet.


"Scott Hedrick" wrote in message
.. .

"bob" wrote in message
m...
opportunity was going 140-150 and "opened at less than
30 feet (from the sounds of it, much less) and then immediately cut
away!

Note that it *wasn't* going "140-150" at the time it was cut away.

"Pat Flannery" wrote in message
...

Well, whatever it was, it has no right being on the same planet as
wonderful, and freedom-loving, American probes.

I thought America hated the French, I mean Freedoms?

From Neil Gerace:
"Diane Wilson" wrote

says...

Bear in mind that airbags are 3/3 and powered descent is 2/3, and
the one failure appears to have been imminently fixable. Either way
would appear to work just fine - it's just a matter of getting the
details right.

If you include lunar landings, powered descent has quite an excellent
track record. And fairly precise landing capability, even without
lunar GPS.

Well, if we include landings in a place where airbags can't be used to
support the argument in favour of powered descent, then we can include
powered descent by aircraft on Earth, where it is already the method of
choice.

Neil, this statement strikes me as very confused. You seem to be
saying that airbags *can't* be used for landing on the Moon. And then
you seem to be saying that *powered descent* is the method of choice
for landing on Earth.

If I'm reading this the way you intended, you may want to check both
of those views!


~ CT