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January 14, 2005



(from John Strickland, NSS board member from Austin, TX)

Descent Timeline: Jan 14, 2005 (All times E.S.T.)

All times are when signals arrive at Earth.

Huygens carrier signal only may be able to be tracked by radio-telescopes, proving probe is still functioning and providing position and speed of probe. Huygens transmits as fast as it takes images. Cassini will not transmit to earth until after it has captured all the Huygens data. Images are taken by 3 camera lenses making a spiral pattern, looking out and down. These can then be combined into panoramas. We already know that Huygens is spinning at the correct rate.

Huygens signal (arrival times)

4:51 am
- probe turns on transmitters.

5:13 - 5:18 am
- Re-entry, shields released, chutes opened and cameras start taking pictures during descent.

~7:34 am
- touchdown on surface (probe motion should stop).

~9:50 am
- batteries on Huygens run out of power.

Cassini Signal - (arrival times)

9:44 am
- Cassini flys below Huygens Horizon, Loss of Signal

9:46 – 10:07 am
Cassini turns towards Earth to begin transmitting data

10:14 am
First post-landing data from Cassini sent to Earth (proof Cassini is working).

10:17 am
Playback of Huygens Data begins (This is when we will know whether data is good).

2:24 – 3:15 pm
Presentation of First Titan Images from ESA/JPL.

5:07 pm
First Playback of data completed.

5:00 – 6_00 pm
Additional Images from Titan from ESA/JPL.

Jan 15

12:00 – 1:00 pm
Early Look at Science Results from Huygens ESA/JPL.


So far, we still have no idea what the radar and infra-red images are showing us, since we have no sample of “ground truth” and since we see very few if any recognizable shapes. There are no shadows sharp enough to reveal surface shapes. The radar shows mainly smooth and rough areas only as light and dark color. Based on the high amount of texture seen in both the radar and near-infra-red images, this seems to be a very young and dynamic surface.

We do not see many if any craters. We see what might be results of a very dynamic surface environment, with possible rivers and streams (but not of water!) Bright areas could be alluvial fans of debris, or the results of tectonics, wind and sand or unknown forces. There should be ice and frozen organic material on the surface. However, the organics might make up a hard, dry soil or sand-like surface material instead of being a sticky goop. There could be small lakes or pools of liquid ethane, and dissolved in it could be methane and liquid nitrogen. There should be a “water table” with the hydrocarbons taking the place of water. Surface conditions: 1.5 atmospheres of pressure at -290 deg F. There should be enough light to take good pictures if there are recognizable shapes. There may be a lot of wind.

We know so little about what a cryogenic environment would be like after billions of years, that we cannot rule out less likely discoveries such as cryogenic life, until we see the surface. The probability of such a discovery may be extremely unlikely, however. No one wants to discuss such unlikely things to the media, especially. There is a good chance that the surface, surface materials and whatever features are formed there may be unlike anything we have ever seen before.


Since the number of critical mission events is much smaller than for a lander, the chances of success are high. Assuming there is no failure of the mission electronics, the most critical events are mechanical ones:

Timers to start the mission sequence

Detection of end of re-entry period

Deployment of Pilot chute

Deployment of Main chute

Release of Front Heat Shield cover

Deployment of main instruments

Deployment of small chute

Surface proximity sensor on

Descent Imager light turned on


Posted by apsmith at January 14, 2005 10:58 AM



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