Slashdot Mirror
Cassini Probe Has Camera Problems
xX_sticky_Xx writes "The BBC is reporting that the last billion dollar NASA probe, Cassini, (enroute to Saturn) is suffering from an unknown source of contamination on its narrow field camera. NASA has attempted to alleviate the contamination, which is causing a haze to appear around images, by "defrosting" it, with so far limited success. Another attempt will be made in January. If this problem can't be resolved this will be extremely disappointing. Cassini is set to expand our knowledge of Saturn more than Galileo did for Jupiter."
What about plain old space dust? According to this article there's enough of it out there to hamper astronomists when viewing celestial objects from earth. More closer to the point this article describes how people involved in space exploration are concerned with peices of space dust, too small to be tracked, causing serious damage to orbiting satelites. The Cassini article says they're pretty sure that it's related to the deep cold of space, which is why they equipped it with heaters. But if it's not related to the cold, it's not out of the realm of posibility that maybe Cassini simply encountered some of this dust? Although you'd have to think the makers of the satelite thought of this already, but who knows.
I posted to
This is from the report sent out:
.Recent instrument activities included two Radio and Plasma Wave Science HighFrequency Receiver calibrations. Engineering activities taking place onboardthe spacecraft this week include an Attitude Control Subsystem high-watermark clear and the uplink of the Mission Sequence Subsystem (MSS) D7.6.1Modules.
Cassini Weekly Significant Eventsfor 12/06/01 - 12/12/01The most recent spacecraft telemetry was acquired from the Goldstonetracking station on Wednesday, December 12. The Cassini spacecraft is in anexcellent state of health and is operating normally. "Present Position" webpage, http://www.jpl.nasa.gov/cassini/english/where/
when you take something from earth pressure to zero pressure you'd be surprised at what will boil off. this is called outgassing, as polymers, etc... lose mass to vapor. the stuff outgassed can then condense on your optics and ruin your pictures. The usual practice is to put everything in a vacuum chamber and get it all out before flight, but this won't always be enough. Also, you can coat surfaces that will outgass, but you need to use anyway (such as electronics circuit boards) with a non-outgassing coating (such as uralane). If some electronics overheat and melt away some of that coating, the materials underneath might, you guessed it, outgass. It is a difficult problem to avoid and it is unfortunate that it might ruin the mission. hopefully not.
Okay, most of the folks here seem to be bashing NASA and jumping to conclusions that the probe is lost. No damn way. They'll come up with a solution soon enough - for one thing, a similar incident occured with the Stardust probe earlier this year. Just take a look at the status reports.
Start at somewhere aroud May 4,2001 and go backwards (by that report, the problem had been fixed). I bet the glitch on Cassini will be fixed just as easily. Note that the problem occured just before christmas, so they probably just tried a "quick fix" to see if it just went away. Like said, they have until 2004(!) 'till Cassini is at its destination to try a number of things. They'll probably get rid of the contamination just by turning on the heaters for a couple of months, but they don't want to start the operation and immediately leave for a christmas vacation (in case something comes up).