Zombie Satellites Return from the Graveyard | Hacker News Reader

Zombie Satellites Return from the Graveyard

spectrum.ieee.org

79 pointssohkamyung41 comments

One of the things persons not involved in the industry find interesting, is that in the entire history of manned spaceflight, no human has ever visited geostationary orbit.

I have talked to a number of people who were mistakenly under the impression that humans occasionally conduct repairs on telecom satellites.

Also this is the first time a (non-classified, that we know about) spacecraft has visited and photographed another satellite in geostationary orbit.

Humans have done something like repairs on telecom satellites... If they got stuck in LEO before insertion to GEO. Also, ISS.

Very, very rarely and at ridiculous cost ($900m+ per launch) by space shuttle in the 1980s as publicity stunts, nothing more.

The space telescope got several repair and upgrade missions.

Since the R+D cost of developing the telescope was already spent, it's hard to believe the incremental cost of building and launching another one would have cost more than a shuttle mission.

LEO is a very, very different thing in terms of exo-atmospheric delta v budget than achieving a circular Geostationary distance orbit with a manned craft.

Which is why I really hope the new space telescope will work, since they can't realistically go out there to fix it.

And then having enough fuel leftover to return to Earth from Geostationary orbit with your manned craft.

And having a craft that can survive the heat load of re-entering the atmosphere from very high speed (as they demoed in an Orion test flight unmanned), if you're in Geostationary and thrust retrograde until your orbit becomes a highly elliptical one with a new perigee of around 100km, you're going to re-enter very hot and fast.

The marginal costs for Shuttle missions were less than that, say about $250 million, and they often launched multiple satellites as well as performing other missions. It’s complicated.

The total cost of the space shuttle program in 2011, adjusted for inflation was $196 billion. It launched a total of 135 times. This is about 1.45 billion per launch.

Maybe I'm wrong, but the Van Allen belts may also be a reason [1]. The ISS and LEO is below the belts, but the geostationary orbit is inside them, which might cause astronauts to be exposed to higher levels of solar radiation.

[1] https://en.wikipedia.org/wiki/Van_Allen_radiation_belt

One of the things persons not involved in the industry find interesting, is that in the entire history of manned spaceflight, no human has ever visited geostationary orbit.

No one has ever stopped in geostationary orbit, but you have to go past where geostationary satellites stay to get to the moon, so quite a lot of people have really.

Excuse my meta-pedantry, but an orbit is not defined only by a height, it requires also an appropriate velocity.

https://en.wikipedia.org/wiki/Orbit

Well yes, you certainly wouldn't want to go to a circular geostationary orbit and then expend a ton of fuel to thrust retrograde, cancelling out all your velocity, which would result in falling straight into the earth. Definitely not like people would think of in common sci-fi where things can just hang motionless in space.

Being in circular geostationary is defined as also having enough velocity for your orbit to remain circular.

You go through the same radius - but aren't geostationary satellites in a different plane?

Trajectories on the way to/from the moon would require a lot of additional delta v to circularize at Geostationary. Or if you're in an orbit that looks like 550 km x 37600 km, when you're at apogee you need a lot of extra delta v spent in prograde thrust to raise your perigee to the same figure.

This area of research and application is fascinating and, as the article alludes, will only become more important in the coming decades.

I also read a related story[0] recently that others may find of interest: A hobbyist was able to track down a satellite whose EOL was supposed to be in _1972_ by using a beefed up HAM radio to scour the sky for its RF.

[0] - https://www.npr.org/2020/04/24/843493304/long-lost-u-s-milit...

There really needs to be mandatory insurance for GEO satellites. If your satellite fails to reach the graveyard orbit, the insurance pays the towing fees.

Reminds me of the series Planetes. I would definitely be a garbage man if it meant working space and EVAs.

Not quite the same, but I'm reminded of the short lived show "Salvage 1", starring Andy Griffith [1]

[1] https://en.wikipedia.org/wiki/Salvage_1

Interesting, I hate that these types of shows appear to be lost to the ages. I can't find it to buy (there are a handful of episodes available for purchase on DVD on Amazon for something like $17/per) and I don't see it come up on streaming services either.

I loved that show when I was a kid. The science was pretty bad, but the stories were great.

One of my all-time favourite sci-fi shows. The setting manages to mix the banal and the excitement of space so well.

In that case you might be interested in Hardspace: Shipbreaker[1] game which is currently in early access. There are some gameplay videos already, for example Scott Manley's[2].

[1]: https://hardspace-shipbreaker.com/

[2]: https://www.youtube.com/watch?v=kj0FKs7l8sA

A neighbor of mine worked on the refuelling mission described here. Basically he uses a library of CAD designs to assemble standardized components for satellites. The more I learn about satellite operations the more impressed I get. My favorite was a zombie satellite that woke up after 25+ years and started transmitting again. Apparently, the solar panels had broken in such a way that they transmitted power through the battery (even though the battery could no longer hold a charge), so periodically the satellite would be in illumination and transmit (but it had a very weird pattern because the satellite was spinning out of control).

It still blows me away that most satellites, if they have a glitch like losing contact with the ground, will go into "Safe" mode- solar panels fully deployed, directly facing the sun, so it's likely there's enough power to recontact. I have enough trouble implementing a PID-driven motor on my arduino that it impressed me what people can do in space.

Lots of material up there, would be interesting to prospect what more tech could be appropriated there for new use-cases.

At https://space-search.io by applying the orbit duration filter lower than 1 (i.e. above geostationary) you can get a good picture of all the satellites currently in that kind of graveyard orbit.

>Graveyard orbits comprise paths at least 300 kilometers above the geosynchronous region, giving the zombie spacecraft room to have their orbits incrementally ground down by the gravity of the sun and moon.

Why is the graveyard orbit higher than the orbit for operating satellites? Doesn't that mean when the orbit eventually decays, that the satellite will eventually fall back into the orbit where all the operating satellites are?

Likely to let these satellites not interfere with the operational satellites right now, and for many decades? Also, the higher the orbit, the more room it has, and the longer it takes to fall from it onto the planet.

Maybe we'll be collecting these satellites after these few decades pass, and use them for something.

At Geostationary distances, there is so little in the way of atmospheric molecules that orbits will not decay over a geological time scale. Humankind could nuke itself into near oblivion, revert to the stone age and rediscover spaceflight in 20,000 years from now and those satellites would still be up there at just about the same altitude.

It's very different in terms of atmospheric drag compared to orbits under 1500km.

I get the impression it’s easier to go for a bigger orbit than deorbit when you’re at GEO.

There's not much going on above GEO, so there's little risk of hitting someone else if/when you lose control of the sat. Orbital decay is pretty minimal at that level.

I guess to prevent dead satellites interferring with new ones comming to GEO from below ? Not sure if that's right though as many GEO insertion orbits often have apogeum much higher than the final GEO altitude.

Assuming a telecom satellite is still controllable at EOL, the TWTAs will be powered off, leaving only the narrow band S/L band command and control channel operational while the orbit is raised slightly.

In addition to the other replies, it's also fine to move your EOL satellite to a sufficiently lower orbit, but it's not really considered a graveyard orbit, it will just decay and burn up in the atmosphere.

I don't quite understand why they don't decrease their orbit to burn up in the atmosphere. It would certainly be the Kerbal way.

Are the satelites too large to burn up?

According to some Wikipedia research “De-orbiting a geostationary satellite requires a delta-v of about 1,500 metres per second (4,900 ft/s), whereas re-orbiting it to a graveyard orbit only requires about 11 metres per second (36 ft/s).”

https://en.m.wikipedia.org/wiki/Graveyard_orbit

Huh, wouldn't have guessed it to be that much, but it makes sense. De-orbiting gets cheaper the higher your orbit is and a geo stationary orbit is high, but not that high.

requires a huge amount of fuel for a geo-stat-sat to get back down.

The Kerbal way is to remember that to lower your orbit, you have to slow down, and to slow down requires propellant. You're moving really, really fast in a geosync orbit, so slowing down to lithobrake your satellite would require a _lot_ of propellant.

Conversely, to raise your orbit, you have to speed up. And since you're only going up a little bit, you only need a little bit of propellant.

While theoretically possible, it is a lot easier to put a "spare" 1500-2000m/s of delta v and fuel tankage on a Kerbal spacecraft than in real life. Unless we invent a magical ion thruster with a specific impulse of 30000 nobody is going to put enough fuel on a Geostationary telecom satellite to lower its perigee below 100km at EOL. That same fuel is better used for station keeping and to extend its service life.

I'll just leave this here: http://orbitofshame.org

Reply on news.ycombinator.com