Huygens' Titan Descent

http://www.space.com/missionlaunches...mm_050114.html

"For those at work who don't have streaming video available........."

LIVE coverage of Huygens' Titan Descent

6:05 a.m. EST:

Space News Writer Peter de Selding reports live from Huygens mission
control:

DARMSTADT, Germany-- A network of powerful ground telescopes has picked
up the signal of Europe's Huygens descent probe 1.2 billion kilometers
away, confirming that the probe is alive as it begins its descent into
the thick atmosphere of Saturn's largest moon, Titan.

European Space Agency officials at Huygens mission control here said the
signal -- no more than the equivalent of a telephone dial tone -- was
detected by a network of 18 telescopes deployed to listen for a signal
coming directly from Huygens.

The biggest of these antennas is the 100-meter-diameter Robert C.

Byrd Green Bank Telescope, operated by the National Radio Astronomy
Observatory in Green Bank, West Virginia.

The signal did not confirm anything beyond the fact that Huygens is
alive. But it was enough to cause a burst of applause here when
announced at 10:35 a.m. GMT (5;35 a.m. EST) today. 'There is a lot of
emotion in this room," said Jean-Pierre Lebreton, Huygens program
manager at ESA. "It's great news."

Leonid Gurvitz, mission manager for Huygens' communications with the
ground telescope network, said 18 telescopes including Green Bank had
been trained to pick up a signal and that it is the network itself, more
than any single telescope, that received the Huygens signal.

NASA's Cassini satellite, which carried Huygens to Saturn orbit, has
been moved into position to receive Huygens mission data during the
probe's 2.5-hour descent into Huygens' thick atmosphere.

A more-complete assessment of whether Huygens' parachutes have deployed
and its heat shield jettisoned to permit the start of observations is
expected to be received by science teams from Cassini around 11:20 a.m.
EST (1620 GMT) today.

6:00 a.m. EST: If it switched on as planned, a microphone instrument
aboard Huygens may allow researchers to recreate the sound of the
probe's descent as it plunged through Titan’s atmosphere, ESA mission
scientists said. The instrument may also record thunder, and Huygens
scientists hope to have at least initial data to present within 24 hours.

5:50 a.m. EST: Cautious ESA commentators stress the Huygens signal is
just a carrier tone. There is no confirmation that the six science
instruments aboard the probe are working as planned.

"It looks like we heard the baby crying," said Huygens mission manager
Jean-Pierre Lebreton from the floor of ESOC mission control. "But
clearly it tells us the probe is alive, the entry has been successful
and we are under parachutes."

5:35 a.m. EST: Huygens speaks from Titan! ESA has confirmed that the
Green Bank Telescope successfully detected a Huygens signal tone. The
signal, a confirmation that Huygen's transmitter is at least
functioning, and activated on time at about 5:18 a.m. EST.

About 600 people are at ESOC mission control for Huygens Titan descent
and some engineers crowded around computer monitors when the signal
confirmation was announced.

"It's a tremendously exciting moment," said John Dodsworth, Huygens
ground manager at ESOC.

This is pretty exciting stuff! I hope and pray Huygens lands safely and
this mission is a success. I'm watching the live feed from NASA TV and
refreshing a good number of websites monitoring the mission. Here's a
real good misson monitor link:
http://www.planetary.org/saturn/huygens_mission.html

-DH

Impact9 wrote:
This is pretty exciting stuff! I hope and pray Huygens lands safely and
this mission is a success. I'm watching the live feed from NASA TV and
refreshing a good number of websites monitoring the mission. Here's a
real good misson monitor link:
http://www.planetary.org/saturn/huygens_mission.html

-DH

We have to remember that Huygens is primarily an atmospheric probe and
that the majority of data will be acquired during the decent to the
surface, if it survives the landing anything that happens afterwards is
a bonus.

JPL is reporting it made the landing and transmitted for 1.5 hours
after impact.

I am a bit puzzled why they only made the probe last the few short
hours after it detached from cassini. They could of built a better
battery when Voyager I is like 28 year and still going. I know it is
like -300F and mechanical things won't operate long in that harsh
environment. Assuming the probe could survive the environment it would
of been nice to be able to tap it for everything possible.

Hopefully the data will be scientifically worth the wait and cost. The
picture cassini took during the trip are nothing short of breathtaking.
Suppose to have 3 more years of cassini goodness!

In article .com,
"Impact9" wrote:

JPL is reporting it made the landing and transmitted for 1.5 hours
after impact.

I am a bit puzzled why they only made the probe last the few short
hours after it detached from cassini. They could of built a better
battery when Voyager I is like 28 year and still going. I know it is
like -300F and mechanical things won't operate long in that harsh
environment. Assuming the probe could survive the environment it would
of been nice to be able to tap it for everything possible.


The issue is how long the orbiter is in range to relay data from Huygens
to Earth. It's only a few hours, so a longer-life battery for Huygens
would have been pointless.

I am a bit puzzled why they only made the probe
last the few short hours after it detached from cassini.

The problem with Huygens is that it comunicates through Cassini. And
Cassini can't just park there .

Ante

"Impact9" wrote in message
oups.com...
JPL is reporting it made the landing and transmitted for 1.5 hours
after impact.

I am a bit puzzled why they only made the probe last the few short
hours after it detached from cassini. They could of built a better
battery when Voyager I is like 28 year and still going. I know it is
like -300F and mechanical things won't operate long in that harsh
environment. Assuming the probe could survive the environment it would
of been nice to be able to tap it for everything possible.
The reason the deep space probes like Voyager, can go on for so long, is
they use radioisotope generators, rather than batteries. A lump of
radioactive material, generating heat. There is enough difficulty getting
authority to launch such generators, and putting one on the surface of
another world, which might potentially at some time in the future (even if
it is not now), become the basis for life, would be a 'no-no'.
Given the short period when Cassini can stay in range, and that the prime
'purpose' of the probes instruments, are to investigate the atmosphere,
not the surface, longer life batteries, mean more weight, which then mean
bigger parachutes, and yet more weight, and suddenly you are over the
available launch payload...

Hopefully the data will be scientifically worth the wait and cost. The
picture cassini took during the trip are nothing short of breathtaking.
Suppose to have 3 more years of cassini goodness!

Yes.

I am a bit puzzled that Huygens internal temperature can be 25 deg C
(ESA streamed video briefing) after the long cold soak of decent and
sitting on the surface for a couple of hours.

Jerry

wrote

I am a bit puzzled that Huygens internal temperature can be 25 deg C
(ESA streamed video briefing) after the long cold soak of decent and
sitting on the surface for a couple of hours.

The scientist who answered the question indicated, with a smile, that the
Huygens probe must be very well insulated.

"richard schumacher" wrote in message news:no-spam-

I am a bit puzzled why they only made the probe last the few short
hours after it detached from cassini. They could of built a better
battery when Voyager I is like 28 year and still going. I know it is
like -300F and mechanical things won't operate long in that harsh
environment. Assuming the probe could survive the environment it would
of been nice to be able to tap it for everything possible.


The issue is how long the orbiter is in range to relay data from Huygens
to Earth. It's only a few hours, so a longer-life battery for Huygens
would have been pointless.

If that were the "only" reason then I would disagree. Cassini will be
passing by Titan again in a few weeks. I would think they could have held
data and then blasted it at the satellite each time it passed.

However, as I understand it that is not really why they kept the life to
only a few hours. I think it had more to do with just getting it down
safely, the weight of the probe on Cassini, cost, and probably just the
general expectation that conditions were not favorable to the life of the
unit being long.

Glenn