Readers may remember this story from 2010:
“Zombie” satellite shuts down critical NOAA NWS systems overnight
It appears the zombie has been brought back from the half dead.
From Slashdot:
The American telecommunications satellite Galaxy 15 has been brought under control after spending most of the year traversing the sky and wreaking havoc upon its neighbors. The satellite is currently at 98.5 degrees west longitude (from 133 west). An emergency patch was successfully uploaded, ensuring that the conditions which caused it to ‘go rogue’ will not occur again. Once diagnosis and testing have been completed, Intelsat plans to move the satellite back to 133 west.
Wikipedia has:
On 23 December 2010, Intelsat successfully regained control over the satellite after the Baseband Equipment Command Unit reset following a loss of lock and full discharge of the batteries, reportedly the most critical phases of the recovery of Galaxy 15 have been completed. The emergency command patch which would allow ground controllers to gain access to redundant BBEs in the event of a similar failure in the future has also successfully been applied to Galaxy 15 according to Intelsat. [32] Definitive plans to transfer Galaxy 15 to a new orbital slot, such as 93° West, and conduct significant in orbit testing of the further viability of the payload and return to service still have not been announced. On 02 September 2010, Intelsat indicated that once Galaxy 15 was fully recovered they would like to move it back to 133° West and then relocate the Galaxy 12 spacecraft for its intended mission at the currently vacant 129° West slot.[33]
That’s some good news to start off the year. Spaceflight now has more
If zombies can be brought back to life, there’s hope for New Year’s revelers everywhere.
A question we need to ponder is what role did “validated” performance models of various Galaxy 15 subsystems play in this remarkable recovery. Having spent
forty years in the aerospace business, I’ve come to appreciate the value of “validated” (usually through extensive, and oftentimes painful, ground tests) models we can count on to find appropriate fixes in case of emergencies such as that encountered with this spacecraft. Too bad most climate scientists and the politicians that support them haven’t gotten the message yet.
Since com sats like Galaxy 15 reportedly cost around $250 million, whoever figured out how to finally resurrect this zombie would seem to deserve a non-trivial bonus.
Seems like whatever “fix” they uploaded to ensure override access to the backups should also be sent post-haste to all similar sats.
If I recall correctly, a null packet caused the original crash. I hope they’ve fixed that little bug.
DaveE.
So, do zombie satellites traverse the heavens, saying “Braaaaainwaves”?
James Hansen did give you enough warning on the effects of global warming on everything on the planet!
A question for the satellite experts out there, just for curiosity’s sake: how much fuel will it take to reposition the satellite back from 98.5 degrees to 133? And how much will that impact on the useful life of the satellite? I’m assuming that satellites are launched with a finite amount of fuel for the positioning thrusters (or whatever they’re called…), and it seems like pushing a satellite through nearly 35 degrees of geosynchronous orbit would burn a lot of fuel. Isn’t that about 16000 miles? Maybe someone can explain how such a major repositioning is accomplished.
Well since I spent much of the 70’s and the 80’s watching all them horrible zombie documentaries I can positively unequivocally concurrently over and over again perfectly pitched state that no good ever comes from bringing a dead agent of a biochemical mechanical automaton back to life. Again!
Put the spell of darwin on ’em, for, OMFG, if they failed to live the first time around, boo hoo on them. :p
Toby Nixon
January 1, 2011 at 11:08 am
Repositioning a sat in geosynchronous orbit takes a surprisingly small amount of fuel, a little sqirt to the rear or forward to move to a higher or lower orbit, then a little sqirt to get back to geosynch. As far as maintaining position, modern sats have a few tricks that do not use any fuel.
Toby Nixon, A very small burn either pro or retrograde will cause the orbit to be a ellipse with a different period from the circular orbit. Eventually the sat will end up in the right place when another small burn will re-circularise the orbit and stabilise the sat at the new position so very small thruster burns will keep it there. Not much fuel required.
DesertYote says: . . . a little sqirt to the rear or forward to move to a higher or lower orbit, then a little sqirt to get back to geosynch. . . .
Mike Borgelt says: . . . A very small burn either pro or retrograde will cause the orbit to be a ellipse with a different period from the circular orbit. Eventually the sat will end up in the right place . . .
The counter-intuitive thing about this is that to move forward, you squirt to slow down. That drops you into a slightly lower orbit with a faster period, so you move ahead. Opposite for moving back. You have to fire your jets opposite the way you want to move.
This satellite should be put out other satellite operators’ misery and dumped in a parking orbit, not put back in service. It’s a proven threat to the fleet.
Seems we have a few space cookies here!
Outstanding!
Nice to see we still have some real brains in this country. Or, that we still know how fo find one or two in some other country to pull our chestnuts out of the fire. Whatever. Nice job!
The change requires very little fuel, but lots of patience. Orbital mechanics is fascinating, and for the snooker players among us, relatively easy. Galaxy 15 off the pink in the corner pocket.
CPUs! CPUs!!
New York Times Headline:
GLOBAL WARMING CAUSING SATELLITES TO GO BERSERK – “Fits in with all predictive computer models”, says former NASA scientist