Slashdot Mirror
ESA to Give New Life to Old Satellites
JPNews writes "The European Space Agency is designing a program (www.esa.int) to re-configure dying television transmission satellites to be used as a XM Radio-like satellite radio network. 'Once in position, 35,000 km away in space, TV satellites will remain in orbit forever, but their useful life amounts to 15 years or less... further life can be squeezed from a low-propellant TV satellite switched over to mobile digital radio broadcasting where precision position control is less important.'"
It's good that they are looking at reusing some of the old junk that we can't effectively remove from space.
Perhaps NASA could sell off some of their old, unused satellites to get (some of) the funding the need?
Work sucked, until it became unemployment, when it became slightly more tolerable. -Tet
I am a little suspicious of motives and lock-in though.
If these are up for a further 15 years, is there any more support after that?
Or would we be locked-in to using a system that by then is even more out of date.
Interesting idea, but care needs to be taken
from: http://www.space.com/news/spaceagencies/esa_25year s_000602.html
:)
However, ESA's biggest achievement of all, explained Bonacina, lies not in any one particular space project. Rather, it's the fact that 15 European nations have successfully worked together, and in cooperation with other non-European space programs, to reach a common goal.
It's amazing how little a program this wide in scope accomplishes
With NASA giving the one-fingered salute to the unfairly maligned "faster-better-cheaper" programme it's nice to see the ESA taking a more pragmatic approach to things. I have a great deal of respect for NASA but I also want to see Europe, China, India and others up the ante, and this seems like a perfect example.
Dammit. Where'd I put my tinfoil hat.
I can get just as unreliable access down here on the ground, thanks.
Most older communications satelites have what are called "transponders"-- they take everything that comes in on a certain band of frequencies and plays it out on another set.
Because usually relatively high-bandwidth analog signals with high quality requirements are sent through these transponders, and the satelites have a relatively small amount of output power, high gain antennas (big satelite dishes) are required to recover the signal, which must be very precisely pointed.
By using digital signals and audio compression technology, suddenly the signals can be narrower bandwidth. Noise is proportional to bandwidth, and since the signal is narrower, signal/noise ratio is improved. This means high-gain antennas may no longer be strictly necessary, and thus the position of the satelite becomes less critical as the orbit decays.
Note that this does not lock us in to a proprietary standard-- if the spectrum is allocated for this purpose, smarter digital transmitters can be put into space for the same purpose later.
Still important is attitude control-- the satelite's antenna must be pointed down and the solar panels pointed in a useful direction. But this often uses gyroscopes, reaction wheels, and magnetic systems-- which do not use propellant.
Finally, battery life is a question. No communications satelite is constantly receiving solar power, so if the satelite is operated while not in view of the sun, batteries on the satelite discharge. Satelites can withstand a limited number of charge cycles before they fail, and this is likely to form the true upper bound on satelite lifetime.
In all, it's a good idea. I imagine we'll see lots of clever ways to emerge on how to use legacy hardware we've put in space, as launch costs remain so expensive.
It would be quite cool, depending on the frequencies, if they could open the sattelites up to hams. There are a few sattelites here and there available for amateur use, but something launched by the ESA is probably waay cooler.
Of course, this all depends on the ability of them to switch which frequencies the sattelites use--I imagine they weren't originally designed to use Ham frequencies. As for "sloppy" orbits, we hams typically have fairly sophisticated tracking equipment: a 486 pc, running any one the free tracking wares, connected to a dual-axis antenna rotator. Makes it a challenge!!
Recursive (adj.): see 'Recursive'
just wondering how long they think they can stop people from hacking the xm network...
broadcasted stuff has almost always been 110% easier to beat (read: harder to find the pirates, arrrrrg!) than conventional cable/wired networks.
Honestly, I really hope so.
I don't think we should completely abandon manned space missions, but the ISS is going to cost $100B over its lifetime-- figuring that the cost of a 4 year university education is $100k, we could create a million more scientists on earth-- and think how much that could do to solve the autonomous control and robotics problems that currently limit unmanned missions.
Right now, basically 2 of the 3 members of the ISS crew are dedicated to doing things to keep the ISS running. Surely with $100B we could get as much real space science done as that one individual who's concentrating on science on the ISS over these next 10 years can, right?
Let's learn what we can now cheaply, and regroup in 10-25 years and go to Mars, or form a colony on the moon, or do something else really radical that broadens the future for mankind.
You're talking about satellites in geostationary orbit, 35,000km out. For reference the ISS is at 400km. They're as close to "permanent" as makes no odds. The moon isn't strictly in "permanent" orbit either, but no one gets too worked up about it.
Never used a TV satelite dish have ya sonny? You have to aim the dish fairly accurately at the satelite, which kinda requires that it be where it should. Since you never get perfect geosynch (IANAOrbitalEngineer, but stands to reason), you need to use little spurts of attitude jets to keep in place. You'll also need these to despin the gyros that maintain attitude from time to time.
The punchline is that these XM radio receivers, like GPS, don't require a dish to be pointed at the satelite, so it's free to stray further from it's assigned station. This allows you to use less fuel in staying in place.
But then, you're probably a troll, so I just wasted my breath.
This kind of thinking is exactly what we need right now. Our space program has kind of a "chicken and egg" problem right now. NASA doesn't really have the budget to do the research we need. Space won't become cheaper until commercial interests get involved, and commercial interests won't touch space as long as it's so expensive.
By eliminating or reducing launch costs, we get more people interested in joining the party. More companies == more research dollars == better space programs for everybody.
This
When you get a group, such as the ESA, doing that, even better.
Kudos to you sir(s).
But according to my education these satellites loose power and can no longer fight earth's gravity after a while, which causes them to fall into the earth's atmosphere and dissentigrate on reentry.
I have a friend that works with satellites for a living.. maybe I should go ask him to be sure...
Shoot Pixels, Not People!
I'll agree. Looking back on history, it just seems like there was no motivation like competition.
David Brin points out America is a peculiar society in that its populace considers its golden age to be in the future. But I wonder if that is really so. We already say "back in the day we were on the Moon".
I'm not saying we are past our peak, but I wonder if something like going to the moon will be where historians put American's peak or if we are going to have the courage to do more.
-------------------
OnRoad: Reporting what happens in America when the police get out of hand.
Let's learn what we can now cheaply, and regroup in 10-25 years and go to Mars, or form a colony on the moon, or do something else really radical that broadens the future for mankind.
The problem is not now, nor has it ever been, a lack of technology or science.
The problem has been, since the days of Skylab, one of money. (Trivia question: what was the first scheduled shuttle mission? A _BOOSTER_ for skylab. Had the shuttle + booster been built in time, we'd have had a space station in orbit for quite possibly just as long as the Russians.)
I used to work in the Aerospace industry. Analog design. Power. RF/Microwave. Robotics. Loved it. But things changed. Layoffs.
So, I have been freelancing for ten years.
I consider myself extremely educated in the physics of why things work, but dumber than shit on "people skills". I easily get tripped up if someone asks me to do something I have good reason to believe won't work, and tell the truth, even though it costs me the job.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
We has a 128kbps VSAT terminal at college supplied by aging ernet satellite. Data rates used to come down to 2kbps yes kilo BITS. Such satellites are normally space junk, however this may allow us to sqeeze the last bit of life from the satellite, and this will result in cost of cummunications to come down pretty much. I wonder why didnt they think of it before!
My Aurora : http://www.youtube.com/watch?v=o91ZsGwJYyg
FB : https://www.facebook.com/TanveersPhotography
I'm not really up on this, but I used to work at a place that made the Intelsat satellites, and some of the people around me were working on this stuff.
You do know that ESA puts more commercial satellites in space than NASA? Of cause if you count military satellites NASA wins. ESA isn't allowed to launch military satellites.
The biggest problem is that ESA need NASA or Russia to ship its astronauts.
Are there any regulations regarding dead satellites? Once a bird is placed in a (mostly) stable geosync orbit, it's going to remain in the general neighborhood for quite a while. I would think it wise to require these satellites to bump themselves down into the atmosphere when they've reached the end of their useful lifetime. The more junk that accumulates up there, the greater the chances for impact-related disasters. Last year ~75 civil satellites were launched.. I expect the total is higher.
Chances are that as time goes by, our travels out into space will increase, putting more craft at risk. It'd be a shame for future generations to be stuck dodging a (relatively) thick field of high-speed objects ranging in size from marbles to large houses. Things to keep in mind...
Adam "Fogie" Fogler -- Professional Paid College Student
I'm wondering how close to XM will this be...is it going to come with the monthly service fee? Because that's my biggest beef with XM. I understand that they need to have some way of making money, and if people are willing to shell out their hard-earned cash to get a couble hundred radio stations, that's fine with me, but I'm not willing to pay $10 a month when I have a host of perfectly viable radio stations to listen to with the equipment I have already, for practically nothing. (Except for those public radio donations. That's a good cause.) Maybe if I was a more hardcore radio listener...or if I lived somewhere that didn't have a good radio selection...I dunno. Does anyone who uses XM want to explain why they think it's worth the fee? I'm a bit curious.
I'd rather have privately-built space stuff, but even blowing the $100B on the space station or a really great fireworks show would be better than blowing it on a war. And if we don't buy college educations for a million or two scientists, we can just as well buy college educations for a million or two liberal arts students so we'll get better literature or at least better-written computer manuals and television shows...
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
I wonder why (comm, spy) sats are not designed to dock with a small propellant containing vehicle that could be launched midway through the sats life to replenish propellant, since this seems to be one of the main limitting factors of sat. usefulness, and launching such a vehicle would probably cost a lot less than a whole new sat.
After all, the Russian's do something very similar with their Progress cargo ships that dock automatically with the ISS and had also done this with Mir before.
Understanding is a three edged sword. - Ambassador Kosh Naranek, Babylon 5