> 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.
> 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!