Galileo! Galileo. Galileo! Galileo frigged-LEO: Easy come, easy go. Little high, little low The European Space Agency (ESA) says it is working “relentlessly” after an “injection anomaly” pushed its two new Galileo sat-nav satellites into the wrong low Earth orbit (LEO). The ESA today said “the satellites are safely under control” and pointing in the right direction at the Sun, at least. The agency is also prepared to …
ESA has already confirmed the satellites were not insured.
As they have a production line that makes 30 of these satellites (with a considerable chunk made by SSTL in Surrey http://www.sstl.co.uk/Divisions/Telecommunications---Navigation/European-GNSS-Programme) it is cheaper to just have them create two extra than paying eye-watering insurance premiums for something that might never happen.
That said, some people think the launch vehicle might be to blame. If that turns out to be the case the launch company might actually have to shoulder some of the cost, depending on their contract.
Isn't this the second and third satellited they've lost, out of the first 6 launched? I believe one of the earlier ones didn't work, although it's possible these two can be salvaged. But it's a bit sad to have lost half of the reserve of 6, in the first year of the program. On the other hand, out of 15 launches you'd expect to lose at least one, no-one's got a perfect record. It's almost as if rocket science was hard...
They are quite a bit off actually.
"The targeted orbit was circular, inclined at 55 degrees with a semi major axis of 29,900 kilometers. The satellites are now in an elliptical orbit, with excentricity of 0.23, a semi-major axis of 26,200 kilometers and inclined at 49.8 degrees, according to Arianespace." http://www.insidegnss.com/node/4165
The biggest problem is the inclination, which is off by 5 degrees. That is a lot. I am no rocket scientist but based on what I gather from people with more knowledge of the issue, being able to solve the multiple ways they are off with the limited amount of fuel they get to perform corrective measures might be very hard or impossible. Spending this fuel now would also reduce their life span
Choosing a reduced life span to get them in the right orbit would mean the project wouldn't suffer the same delay as launching new ones. However, it would still come at a cost as they would need to be replaced sooner than anticipated.
"shortened life" is relative.
If the orbit can be circularised, at 24,000 miles up they will take several thousand years to come down.
The main issue is not wasting too much fuel (needed for stationkeeping and solar pointing), although these do have ion thrusters.
I don't think station keeping is much of a problem, it's not like geostationary orbit where they need to be within a small box over the equator as they are actually intended to be in a geosynchronous orbit (2 orbits in 24 hours is what the GPS SVs do, not sure if Galileo is the same).
In theory all that matters is that they are in a predictable position, fill in an empty part of the constellation and can be found and their ephemeris data measured very accurately using the earth stations, the satellites just send this information back to the GNSS receivers of the users which then perform the calculations needed to locate themselves.
That shouldn't be a problem. Just send up Harry in the Salvage 1 to give it a bit of a nudge or maybe refill the tanks.
Oh, wait that was fictional. I meant we should send up the space shuttle to refuel...
Dammit! Not only do I not have a flying car, all the tech we thought we had seems to be disappearing too.
Navigation Satellites like Galileo (and GPS after which it is modelled) broadcast the details (or ephemerides) of their orbit in their navigation message - stuff like orbit inclination, radius, eccentricity etc etc. I haven't checked, but the numeric range of these paarmeters should allow the description of these 'non-nominal' orbits to the same level of accuracy. So in theory they can be used in their current orbits. In will bugger up the coverage calculations as they won't be in sync with the other satellites in the three nominal planes. I'll bet there are some sleepless nights at ESTEC now with people running constelation simulators. There's probably no threat to other satelltes as MEO (mis Earth Orbit) is basically empty apart from sat nav satellites - the radiation levels are high. Sat nave does not need GEO stationary orbits and LEO orbits near the earth would not last long enough due to the drag of the Earth's atmosphere
Interestingly, Boeing's patent on lunar flybys seems to only apply to satellites launched in March or September.
It also appears to have lapsed.
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