> The agency had to modify its 15m dish in Perth to get through to Phobos-Grunt. This required widening the antenna's beam to catch the probe in its uncertain orbit.
> Perth also reduced the power of the transmission to make it more like the sort of faint X-band signal the craft would expect to hear at Mars.
> "We were able to get our transmission in and the commands that were sent then allowed the transmitter on the spacecraft to be turned on; and then we saw the signal coming back into our big dish," explained Dr Klaus-Juergen Schulz, the head of the ground station systems division at Esa-Esoc.
The hacker ethic is alive and well in space operations!
There's a long history of this sort of thing. All communication with Galileo, for instance, was via the auxiliary transmitter intended to properly target the much bigger main transmitter; the main transmitter dish was damaged on launch.
As part of the measures to increase the efficiency of transmission, a new coder/decoder was developed to add about 2dB to the SNR to the transmitter.
It was called the Big Viterbi Decoder, or BVD for short. The noted information theorist Ed Posner, who was on the design team, quipped, "I've worked on hardware and on software for space systems, but this will be the first time I've worked on underwear."
There's also a movie on something like this, about the moon landing: "The Dish" (http://www.imdb.com/title/tt0205873/). Was a good movie I believe, but it's been a while.
> The best scenario is that the issues are related to a software anomaly, and that engineers can then upload new commands.
Dear Santa, please bring me a 15m dish for Christmas, because I badly want to try to upload new commands too.
More seriously, I never realized that there are probably a lot of hackable things flying above our heads, provided that you have the appropriate equipment.
There certainly are hackable things flying over your head. However, with your 15m dish men in black suits will zero-in on your ___location in a flash, and you'll be behind bars before you know it - probably before you can focus on the target out on space. So I'd suggest palling around with the chinese and russians and see if they'll provide you with some AA if you plan on doing that. Like anything else these days, you use cut-and-dried old fashion hacking techniques to gain access to the computer systems. There was just an article on this site about the russians hacking into some sewage plant. They didn't hack the valves and equipment directly, they guessed a password and got into the computers controlling the whole thing.
I'd bet, though, that many things aren't very well protected, because people designing space systems assume that nobody is going to try to mess with them, and also because they probably use proprietary communication protocols.
But just imagine how cool it would be to ssh into a satellite :)
A few years ago I worked for a satellite imagery company. I can tell you that communications with space vehicles in orbit are heavily encrypted using very strong and very proprietary algorithms that require special hardware. Because of this encryption, I had to acquire a government security clearance.
Actually no, these things pretty much fly in the open, chiefly out of necessity (recovering from bit transmission errors is much more complicated when encrypted, and uses up valuable power as well). Usually you have to know a prefix code to get the probe to listen, a la Dr. Strangelove.
It really is security-through-obscurity. Though that definitely isn't considered safe, a lot of spacecraft (especially deep-space ones) are pretty damn obscure. The true weakest link is the security at the ground station, not some fool with a 40 meter dish.
> Perth also reduced the power of the transmission to make it more like the sort of faint X-band signal the craft would expect to hear at Mars.
> "We were able to get our transmission in and the commands that were sent then allowed the transmitter on the spacecraft to be turned on; and then we saw the signal coming back into our big dish," explained Dr Klaus-Juergen Schulz, the head of the ground station systems division at Esa-Esoc.
The hacker ethic is alive and well in space operations!