Jupiter question

Here's a question I've always wondered about. How come no space probe (that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

I think this would be fascinating. Is it because the atmospheric
temperature would melt the probe/camera before it reached the low orbit
and/or descent? Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

Larry

In article ,
Larry G wrote:
Here's a question I've always wondered about. How come no space probe (that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere?

Because there has only ever been one probe into Jupiter's atmosphere --
the Galileo atmosphere probe -- and various design limitations (not least,
the fact that it was built with early-1970s electronics) made a camera
impossible there.

Or at least photos from a very low orbit.

Very low Jupiter orbits tend to involve very high radiation doses and are
most unhealthy for electronics. The only probe that has really passed low
over Jupiter was Pioneer 11, which made one quick flyby; it had only a
very simple camera system, and didn't get many pictures, especially from
high-radiation areas where the camera kept having to be reset.

Both Galileo and its probe passed through such altitudes on their way into
Jupiter, of course, but the probe had no camera and Galileo's antenna
problems prevented real-time image transmission during its last hours.

...Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

There is interest in doing more Jupiter atmosphere probes -- especially
since Galileo's probe, annoyingly enough, seems to have gone into a fairly
unusual area and so we're not sure how its data generalizes to Jupiter's
atmosphere as a whole -- but so far, no funded missions.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

"Larry G" writes:

Here's a question I've always wondered about. How come no space probe
(that I'm aware of) has taken photos inside Jupiter's (or any of the
large planets') atmosphere?

Limited uplink bandwidth plus limited available light.
Both factors imply that It Would Cost Too Much To Fly It.


Or at least photos from a very low orbit.

Define "low."

Also, _too_ low, and atmospheric drag sucks in your Incredibly Expensive
Space Probe.


I think this would be fascinating.

"Fascinating" doesn't always Pay The Bills.


Is it because the atmospheric temperature would melt the probe/camera
before it reached the low orbit and/or descent?

No. It is because of Limited Bandwidth, Limited Light, and Limited Budget.


Are there any known plans to send a probe that could withstand the
extreme temps (or gravity?) to achieve such a feat?

No.

(BTW, "gravity" is hardly an issue; the Jupiter Entry Probe experienced
=FAR= higher gee-loads during the atmospheric entry.)


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

(Gordon D. Pusch) wrote:
"Larry G" writes:

Here's a question I've always wondered about. How come no space probe
(that I'm aware of) has taken photos inside Jupiter's (or any of the
large planets') atmosphere?
[snip-o-rama]
Limited uplink bandwidth plus limited available light.
Both factors imply that It Would Cost Too Much To Fly It.

Is it because the atmospheric temperature would melt the probe/camera
before it reached the low orbit and/or descent?

No. It is because of Limited Bandwidth, Limited Light, and Limited Budget.

Limited bandwidth and limited budget I'll buy, but not limited light.
Modern imaging technology is just too good to give that any weight.
Keep in mind that the '70s vintage Voyager spacecraft did a fair job
out at Neptune with light less than 2% of the levels at Jupiter.
Modern imaging systems are light-years beyond what was available in
the '70s, so much so that "night-vision" systems can be mass produced
and sold commercially at reasonable prices. The sorts of things
available for use on a multi-million dollars spacecraft give little
wiggle room for ideas that a probe would not actually be able to image
anything worthwhile, even "deep" within Jupiter's cloud cover(s).

Limited bandwidth, too, is not so much a primary concern as much as a
secondary concern due to limited *time*. The setup for imagery on
Saturn's moon Titan will be no better than within the Jovian
atmosphere but there at least the probe has the chance to land on the
surface and spool off all its recorded images. Whereas with Jupiter
you'd likely need some sort of baloon (which, I hardly need to say,
would be difficult) to keep the spacecraft high up before it got
crushed and/or melted when falling to lower levels in the atmosphere.
Either that or really high bandwidth communications which work well
over several hundreds of thousands of kilometers (which, I hardly need
to say, would be difficult). There are other options as well but
they're too risky and too novel to be tried by the current crop of
folks in charge of interplanetary missions.

In article ,
Christopher M. Jones wrote:
Limited bandwidth and limited budget I'll buy, but not limited light.
Modern imaging technology is just too good to give that any weight.
Keep in mind that the '70s vintage Voyager spacecraft did a fair job
out at Neptune...

Bear in mind that the only probe yet to enter Jupiter's atmosphere was
built only a few years after the Voyagers, with quite similar technology.

The two situations also are not quite comparable. Voyager 2 at Neptune
could, and did, use quite long exposures. That option isn't available
when parachuting down through an atmosphere.

...The setup for imagery on
Saturn's moon Titan will be no better than within the Jovian
atmosphere but there at least the probe has the chance to land on the
surface and spool off all its recorded images.

No, the data and images from Huygens will be coming back in real time.
There is no assurance that it will survive the landing, since we know
almost nothing about the nature of the surface. Whether it will remain in
communication is also a little uncertain; in particular, if it lands on a
slope, its antenna may be pointed too far off vertical for Cassini to
continue receiving it. And finally, even if all goes well, it won't be
sending data from the surface for more than a half hour or so (I forget
the exact number), partly because its batteries will be getting very low
but mostly because Cassini will go below its horizon. Huygens is
primarily an atmosphere probe, not a lander, so long surface life was
not a design goal.

The difference in imaging is partly better technology, but mostly just
that the people designing Cassini/Huygens gave imaging a higher priority.
There wasn't any law of nature saying that the Galileo atmosphere probe's
data rate had to be too low for effective imaging; that number emerged from
the design tradeoffs that were made, based partly on the assumption that
the probe didn't *need* a high data rate.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

"Larry G" wrote in message
...
Here's a question I've always wondered about. How come no space probe
(that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

I think this would be fascinating. Is it because the atmospheric
temperature would melt the probe/camera before it reached the low orbit
and/or descent? Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

Larry


Only one probe has entered Jupiter's atmosphere.
The probe from the Galileo spacecraft.
It, unfortunately didn't have a camera.

"Larry G" wrote in message
...
Here's a question I've always wondered about. How come no space probe
(that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

I think this would be fascinating. Is it because the atmospheric
temperature would melt the probe/camera before it reached the low orbit
and/or descent? Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

Larry


Only one probe has entered Jupiter's atmosphere.
The probe from the Galileo spacecraft.
It, unfortunately didn't have a camera.

"Larry G" wrote in message
...
Here's a question I've always wondered about. How come no space probe
(that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

I think this would be fascinating. Is it because the atmospheric
temperature would melt the probe/camera before it reached the low orbit
and/or descent? Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

Larry

Wouldn't melt it, it would be eventually crushed. The atmosphere is cold
and gets progressively colder and with higher pressure as it gets thicker.

There's nothing to see - ever been inside a fog bank? That's what it'd look
like.

--
Alan Erskine
alanterskine(at)hotmail.com


Due to Optusnet's failure to deal with
the current virus SPAM attack, respond
to alanterskine(at)hotmail.com

In article , Larry G wrote:
Here's a question I've always wondered about. How come no space probe (that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

I think this would be fascinating. Is it because the atmospheric
temperature would melt the probe/camera before it reached the low orbit
and/or descent? Are there any known plans to send a probe that could
withstand the extreme temps (or gravity?) to achieve such a feat?

Bear in mind there have only ever been two probes to do anything more
than a flyby of the gas giants, and one of those is still en-route...

Galileo did carry a small probe to be dropped into Jupiter, but a
variety of reasons - the very limited amount of data transmission that
was possible being a major one - meant that equipping it for photography
wasn't a reasonable option. I've seen the decision characterised as
"some interesting science, or two photographs".

http://groups.google.com/groups?selm...0spsystems.net
http://groups.google.com/groups?selm...0spsystems.net
(& following thread)
for a couple of posts discussing it; there's more, but I don't want to
spend all evening googling g

Cassini also has an entry probe, but this is designed to be dropped onto
Titan - undeniably a more interesting target...

--
-Andrew Gray

"Larry G" wrote in message ...
Here's a question I've always wondered about. How come no space probe (that
I'm aware of) has taken photos inside Jupiter's (or any of the large
planets') atmosphere? Or at least photos from a very low orbit.

Galileo dropped a probe into Jupiter's atmosphere, but it did not have
a camera. I don't recall the reason why. The probe successfully
entered the atmosphere, deployed its parachute, and radio'd
atmospheric chemistry data back to Galileo/Earth.

So it's quite possible to do this, it just hasn't been done, and
voyages to the major planets are infrequent.

Mike Miller, Materials Engineer