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Coffee House => Coffee House Boards => CH / Science and Technology => Topic started by: blobrana on March 18, 2004, 12:21:58 AM
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I noticed an article about NASA/ESA Ulysses spacecraft's Radioisotope Thermoelectric Generator, or "RTG." is starting to run down, and soon it won't have enough to keep itself warm.
The spacecraft was launched in 1990 “on a five-year mission” to explore strange new..,er, the Sun, and originally its reactor produced 285 watts of power, but now 14 years later, it's down to 207 watts. If it gets too much lower, the spacecraft won't be able to operate the heaters that keep the fuel flowing. Without this fuel, it won't be able to orient its main antenna to-wards the Earth to transfer data.
"They say revenge is a dish best served cold... it is very cold... in SPACE!" [EDIT: Khan Noonien Singh ]
The craft has gathered new data about the speed and direction of the solar wind. It discovered the 3D shape of the sun's magnetic field. It recorded solar flares on the sun, and super-solar flares from distant neutron stars. Ulysses even flew through the tail of comet Hyakutake.
The mission was supposed to end in 1995, but because Ulysses was so successful, NASA and the ESA granted three extensions, most recently in Feb. 2004.
Ulysses is now has to keep going until 2008, thirteen years longer than originally planned!
Ulysses' extended mission, as before, is to study the sun. But at the moment Ulysses is far from our star. It's having a close encounter with Jupiter, studying the giant planet and its magnetic field. Sunlight out there is 25 times less intense than on the Earth, and Ulysses is getting dangerously cold...
Fuel lines are critical to the mission. They deliver (toxic) hydrazine propellant to the ship's eight thrusters. Jut now they're hovering about 3 degrees above zero, but if they freeze ... trouble.
Ever had burst pipes in winter...? When hydrazine thaws, it expands, possibly enough to rupture the fuel lines.
No thrusters means no communication. The mission would be `lost in space`.
Ulysses will turn away from Jupiter and eventually head back to the sun. And eventually solar heating will keep the hydrazine warm, and the on-board heaters can be turned off...but that won't happen until 2007.
Strange that a `Sun probe` may freeze to death...Huh...
[CORRECTED TODAY]
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The only way would be to turn off any non-vital equipment to keep the heaters alive until the probe can get closer to the sun. Another would be to abandon the probe. After all, it's mission was completed long ago.
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Pity we don't have any space mirrors accurate enough to reflect a beam of sunlight out into space and onto the probe. Or even use lasers to boost the power from the solar panels. But the accuracy needed for either would be mind-boggling...
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Poor Ulysses :-(
It's sad to watch such a dedicated and loyal servant die slowly an painfully.
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> Revenge like a dish best served cold. Very cold like deep space...
Not really. Space is mostly vacuum, and isn't hot or cold.
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T_Bone wrote:
> Revenge like a dish best served cold. Very cold like deep space...
Not really. Space is mostly vacuum, and isn't hot or cold.
Well, yes, if you are going to be all picky and thermodynamic about it :-D
However, I think Blobrana meant cold as in "lack of significant thermal radiation". That far from any decent heat source, any object (eg the probe) will radiatively bleed its own heat away into the void and freeze...