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]
