Comments on: Ulysses’s odyssey comes to an end

By: Cyde Weys

Cyde Weys — Thu, 28 Feb 2008 20:35:35 +0000

Are we sure it stole energy from Jupiter to get into the tighter orbit? There’s less energy in a tighter orbit, so maybe Jupiter stole energy from the probe rather than the other way around?

By: Wayne

Wayne — Thu, 28 Feb 2008 04:26:55 +0000

Buzz,
I don’t remember the source, but I think you’re right about the transmitters. That’s not to say that you can’t get science data from a low-gain antenna (see Galileo mission), but it certainly puts a crimp in things.

By: Buzz Parsec

Buzz Parsec — Thu, 28 Feb 2008 01:09:56 +0000

The article I read (spaceflightnow.com) was a little confusing, but I think they turned off one of the transmitters to save power so they could redirect that power to the heaters to keep the hydrazine from freezing, but then when they tried to turn the transmitter back on, it didn’t work, so they figured without the transmitter and with the general wearing out of the other systems, it wasn’t worth keeping it going. (The article didn’t say, but I presume Ulysses is still communicating with the Earth using a low-power transmitter, so they know it’s still alive, but the high-power transmitter is needed to send back significant quantities of scientific data, rather than just “yup, I got that message” stuff.)

By: Dunc

Dunc — Wed, 27 Feb 2008 11:31:35 +0000

Props to the Cream fans, but surely Ulysses 31 is the more appropriate reference? " Ulysses, Ulysses, soaring through all the galaxies, in search of Earth, flying in to the night."

By: Patrik

Patrik — Wed, 27 Feb 2008 07:00:30 +0000

A Science@NASA article from 2004 mentioned that the power level is down to 207 W from 285 W (30W of which should be due to decay if Pu 238 is used) which already then caused problems with the propellant heaters if they tried to use all the instruments and communicate at the same time. My guess is that the Voyeger probes where more overengineered and that they usually don’t run all their instruments.

By: Troy

Troy — Wed, 27 Feb 2008 05:45:58 +0000

When the MESSENGER data was delayed because of a com issue with Ulysses I was SHOCKED that it was still going. I’m surprised that the radioactive supply is shot after only 17 years though since the Pu 238 half life is something like 85 years. Voyager is still communicating more than 30 years later. My understanding is that it isn’t the amount of radioactive materials, rather it is the degrading of the thermocouple that harvests the energy.

By: ColoRambler

ColoRambler — Wed, 27 Feb 2008 04:32:11 +0000

My only regret for this mission? It didn’t swing by the asteroid 201 Penelope.

Moreover, it didn't hang around here for a few years as part of the mission. Bummer.