- Cassini-Huygens Mission status report

"Christopher M. Jones" wrote in message
...

I don't, but you KNOW that the ESA would have grabbed
some of the credit if Beagle-2 would have succeeded,
even though it was not their mission.

I note that not many of the Cassini status reports mention Huygens in any
way. So it works both ways.

In article ,
Neil Gerace wrote:
I note that not many of the Cassini status reports mention Huygens in any
way. So it works both ways.

It was most interesting to compare the ESA and JPL prelaunch photos. ESA
photo of Huygens ready to leave for JPL: big bold ESA logo on its center.
JPL photo of Cassini after Huygens had been mated to it: Huygens is right
in the center of the photo... but whether by actual alteration, clever
lighting, or just photo editing, that ESA logo is so washed out that you
can't even see it unless you know exactly where to look.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Neil Gerace wrote:

Well that's interesting. Could we use aluminium or would we need to splash
out on titanium or something else, for instance?


Actually Mercury is a lot easier to deal with than Venus; Mercury has a
hot surface (at least on the side that's presently facing the Sun as the
planet rotates), but virtually no atmosphere to conduct heat to the
lander; so a reflective sunshade should keep the lander cool as it rests
in the shade's shadow. And I'm pretty sure we can generate sufficient
electrical power with solar panels also... :-)

Pat

In article ,
Pat Flannery wrote:
Actually Mercury is a lot easier to deal with than Venus; Mercury has a
hot surface (at least on the side that's presently facing the Sun as the
planet rotates), but virtually no atmosphere to conduct heat to the
lander; so a reflective sunshade should keep the lander cool as it rests
in the shade's shadow.

Alas, radiation from the surface can also be pretty fierce, so it's not
easy to set up a shade configuration that shields the lander from
everything except cold black sky.

(Even orbiters have problems with this: a low circular orbit is great for
mapping, but it means the spacecraft spends the daylight half of each
orbit being roasted from *both* sides. Dealing with that simply isn't
considered feasible, last I heard; both Messenger and Bepi-Colombo will be
in quite elliptical orbits to give them a chance to cool off at high
altitude in between low passes.)

It would be easier if the landing was at fairly high latitude, where
temperatures are lower and there's a known region (directly overhead)
that's always cold sky.

And I'm pretty sure we can generate sufficient
electrical power with solar panels also... :-)

This is actually not to be taken entirely for granted, because solar
panels do not work well at high temperatures. Keeping them cold is a of
an issue even in Earth orbit, and the problem assumes really serious
proportions on or around Mercury.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

On 2004-06-02, Neil Gerace wrote:

"Christopher M. Jones" wrote in message
...

I don't, but you KNOW that the ESA would have grabbed
some of the credit if Beagle-2 would have succeeded,
even though it was not their mission.

Editorial comments on the ESA-Beagle relationship:

http://mainlymartian.blogs.com/semij...n_a_diffe.html

I note that not many of the Cassini status reports mention Huygens in any
way. So it works both ways.

Bear in mind that Cassini has been cruising for a long, long time; every
now and again, not often, they've turned Huygens on and checked it's not
dead yet. Even at the moment, there's still a good while to go before H.
needs to be alive and functioning, so it's remaining dormant.

A status report that kept saying "Huygens is still bolted firmly to the
centre mounting strut at three points, and has not yet fallen off" would
rival the "operating nominally except when they're not" line of the ISS
ones for unuseful information... ;-)

Thought - will a sucessful Huygens upstage Cassini? I'm not sure it
really has the photo-abilities to do it, IYSWIM.

--
-Andrew Gray

In article , "Christopher M. Jones"
wrote:

Mike Flugennock wrote:

(massive self-snippage)

So, any theoretical bets on whether or not a Mercury lander would
survive any longer than a Venera? Seems that'd be a place where
forcible conversion of the spacecraft into semi-molten slag would
become a _really_ serious issue.

You gotta consider the thermal dynamics. Venus is a
really hard problem because there's just so much heat
to deal with, 60 bars of superheated atmosphere is a
heck of a lot of heat energy to reckon with, and it
touches your spacecraft *everywhere*. And then
there's the wind and whatnot keeping the air that same
temperature no matter what kind of cooling you bring
along. But Mercury you just have to deal with the Sun
(same problem as with an orbiter, solvable) and contact
with the ground, which can be handled pretty easily
with a couple insulated legs...

...All that aside, you can always just put it in the shade
or semi-shade, since Mercury has a slow rotation rate...

Now, that might make for some interesting astronomical observations,
especially looking _outward_, towards Venus and Earth...though the rest of
the stars probably wouldn't look all that different.

But that might make seeing things a bit difficult. If
you brought along an RTG and a spot-light then you'd be
set though...

Y'know, a flood would be really handy for sure, but I'll bet by the time
somebody finally bothers to put a lander on Mercury, somebody will have
also developed a CCD even more sensitive under low light than what we have
now*. Actually, along with a flood, for a lander camera on Mercury, we may
also want a set of heavy filters -- so we don't fly our camera all the way
there only to have it do an Al Bean on us. Something that lets us screen
out the Sun's disk might also be good to have as Mercury sounds like a
nice place to try and do some close-up coronal mass ejection observations
-- though I can't recall right offhand whether or not any CMEs have
stretched out far enough to "lick" Mercury.

Just for fun I'll toss out this: what about a Mercury
rover? Now that I'd really like to see...

Well...that'd be really sweet, I'll agree, but heat, I think, would be
such an issue there that right now it'd be fantastic to just get a
stationary lander there, functioning, sending data/fotos back of
reasonable quality (actually, I wonder if anyone designing a lander for
Mercury has considered some kind of collapsible-for-launch/cruise and
deployable-after-landing combination photovoltaic array/sun
shade...something that shades the lander but lets it get fotos of its
surroundings under full sun). Now, dealing with heat issues for a _rover_
-- all those moving parts, y'know -- sounds like an even tougher problem.

I'm guessing a landscape looking as dead and hard-boiled as Luna, only a
little more scorched-looking, perhaps. (;^ I've seen some fairly good B&W
flyby probe images, but haven't found anything in color of Mercury.
Nothing spectacular, I'm sure; probably similar to the country between
Yuma and the mountains bordering the far eastern edges of San Diego
County, except covering a whole planet.

Something else I've wondered about the night side on Mercury is just how
dark it'd get on a planet that small, that close to the Sun...still pretty
damn' dark, probably, given the lack of atmosphere, but that close, I've
still wondered what kind of "edge light" you'd get. I'll bet the Sun
appears really huge there in the daytime -- and I'll bet sunrises look
downright scary -- and I keep trying to imagine if that'd have any effect
on night-side visibility.






* Speaking of which, I could really get into some dawn/dusk shots from
Spirit, with Husband Hill silhouetted by/brilliantly lit up by the low
Sun, perhaps with Earth and/or Jupiter as a morning/evening star, right
about now (which way are the Columbia Hills oriented, anyway...?). They've
posted one already from Opportunity iirc, just after sunset, with the
Earth as a blue evening star, which was excellent, but a bit late to catch
the sky changing colors. I'll bet the sky colors there, right at dusk, are
really something.

--
"All over, people changing their votes,
along with their overcoats;
if Adolf Hitler flew in today,
they'd send a limousine anyway!" --the clash.
__________________________________________________ _________________
Mike Flugennock, flugennock at sinkers dot org
Mike Flugennock's Mikey'zine, dubya dubya dubya dot sinkers dot org

In article , "Neil Gerace"
wrote:

"Christopher M. Jones" wrote in message
...

I don't, but you KNOW that the ESA would have grabbed
some of the credit if Beagle-2 would have succeeded,
even though it was not their mission.

I note that not many of the Cassini status reports mention Huygens in any
way. So it works both ways.

Well, Huygens really hasn't started doing what it's supposed to do yet,
except not-very-exciting things like reporting its health periodically,
iirc.

--
"All over, people changing their votes,
along with their overcoats;
if Adolf Hitler flew in today,
they'd send a limousine anyway!" --the clash.
__________________________________________________ _________________
Mike Flugennock, flugennock at sinkers dot org
Mike Flugennock's Mikey'zine, dubya dubya dubya dot sinkers dot org

In article ,
wrote:

On 2004-06-02, Neil Gerace wrote:

"Christopher M. Jones" wrote in message
...

I don't, but you KNOW that the ESA would have grabbed
some of the credit if Beagle-2 would have succeeded,
even though it was not their mission.

Editorial comments on the ESA-Beagle relationship:

http://mainlymartian.blogs.com/semij...n_a_diffe.html

I note that not many of the Cassini status reports mention Huygens in any
way. So it works both ways.

Bear in mind that Cassini has been cruising for a long, long time; every
now and again, not often, they've turned Huygens on and checked it's not
dead yet. Even at the moment, there's still a good while to go before H.
needs to be alive and functioning, so it's remaining dormant.

A status report that kept saying "Huygens is still bolted firmly to the
centre mounting strut at three points, and has not yet fallen off" would
rival the "operating nominally except when they're not" line of the ISS
ones for unuseful information... ;-)

Thought - will a sucessful Huygens upstage Cassini? I'm not sure it
really has the photo-abilities to do it, IYSWIM...

Tough call. Cassini's fotos of Saturn, the ring system, and the moons will
be crisp, clean, colorful ooooh-and-aaahhhh material for sure, but
still...a look that close at a moon of a planet besides our own for the
first time, even though perhaps only in B&W -- especially if it can
survive long enough to send back some fotos from the surface, or maybe "at
sea" -- sounds especially fascinating.

Actually, as excellent as Cassini's fotos are promising to be, the thing
that's always excited me the most about this mission has been the Titan
landing. Images from the surfaces of other worlds, viewed for the first
time -- whether from Luna, Mars, Venus, or now, Titan -- have always been
something exciting to me.

--
"All over, people changing their votes,
along with their overcoats;
if Adolf Hitler flew in today,
they'd send a limousine anyway!" --the clash.
__________________________________________________ _________________
Mike Flugennock, flugennock at sinkers dot org
Mike Flugennock's Mikey'zine, dubya dubya dubya dot sinkers dot org

In message , Mike
Flugennock writes

Actually, as excellent as Cassini's fotos are promising to be, the thing
that's always excited me the most about this mission has been the Titan
landing. Images from the surfaces of other worlds, viewed for the first
time -- whether from Luna, Mars, Venus, or now, Titan -- have always been
something exciting to me.

Absolutely. I've seen them all - the Russian moon pictures which gave
the Daily Express their scoop; the Surveyor 1 pictures - that was a live
broadcast; the first Mars pictures with the dodgy colours; and Venus. I
hope to live long enough to see pictures from a Jupiter probe, rather
than the floppy-disk worth of data you got from Galileo.
--
What have they got to hide? Release the full Beagle 2 report.
Remove spam and invalid from address to reply.

In article ,
Andrew Gray wrote:
Thought - will a sucessful Huygens upstage Cassini?

Assuming Huygens works completely, and especially if it survives touchdown
and gets some surface photos... then yes, temporarily. Look at Beagle 2
vs. Mars Express. If Huygens was a long-lived lander, then Cassini could
count on being in its shadow for quite a while; as it is, I expect Cassini
will slowly emerge back into the limelight.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |