A graveyard orbit sounds like it will be flying around up their indefinitely as high speed shrapnel. Does anyone know why they would choose this instead of destroying it on re-entry?
Satellites in lower positions actually have to maintain their orbit due to orbital decay. Because Geostationary orbit is so far away, there's a lot less decay.
For example SpaceX's starlink only has a lifespan of 5 years, and this is because of their low orbit.
For physical intuition, uh, the atmosphere is a hundred times further away than the graveyard orbit.
De-orbiting to hit the atmosphere at a shallow angle would actually take slightly less delta-v than de-orbiting to a straight plunge to Earth. But both are much larger than the delta-v required to get to a graveyard orbit.
So we're in a stable orbit with a high periapsis (closest part of our orbit to earth). To de-orbit we need to lower the periapsis so that it touches the atmosphere, and on each pass the satellite will slow down, further lowering the apoapsis and periapsis. The problem is that to do this we have to burn all that horizontal velocity that's keeping us in orbit in the first place, which is a crapload.
An alternative is to instead change the orbit so it's no longer in geostationary orbit and potentially interfering with live satellites, so instead they just push the satellite further out into the "graveyard orbit".
There's 100x difference in the needed energy for the two methods, and I'm sure you can see why most would opt for the graveyard orbit.
EDIT: To add, it's actually rather difficult to "plunge into earth". To do this you need to burn all of your horizontal velocity (I think that's around 3.07 km/s in geostationary orbit?). Reaching the sun is actually really difficult as well for the same reason, you have to lose all of your horizontal velocity, and earth has a ton.
I HIGHLY recommend both of them.
Yes. you can accelerate away from the Earth and have a lower periapsis (conversely, you can accelerate towards the Earth and have a higher apoapsis). The only way you can maintain the same periapsis is by accelerating in the same direction you're going. Highly impossible in an explosion.
Also note, it is impossible to raise periapsis in a single event (or single time frame), except by leaving Earth orbit entirely (i.e. eject to planetary space)
Additionally, it takes a lot of fuel to be able to de orbit high altitude satellites.
The issue with space debris is with orbits in the 500-5,000km range. Lower than that and the debris will reenter quickly, higher and you start getting spread out enough to not matter as much.
They're also in a ring in the plane of the equator. Easy to avoid.
So they already are aligned and just need to be moved to a higher orbit.
Geosynchronous orbits are orbits at the same altitude, but not necessarily aligned with the equator. Most of what I know about orbital mechanics I learned from Kerbal Space Program, but given that it's very expensive to change orbital inclination, I would be shocked if geosynchronous satellites were returned to a flat inclination before being disposed of.
Because the ∆v required to re-enter the atmosphere is significantly higher than that required to leave geosynchronous orbit for a higher graveyard orbit.
But yes, ultimately it will remain up there as "high speed shrapnel" - which is not an ideal situation, and continuing to treat disposal as we have may put us in a situation where these orbits become so full of high speed garbage that they are unusable. As a species, we need to do more work on cleaning up our space garbage before it's too late.
Kurzgesagt actually has a great video on the topic of space debris for anyone interested: https://www.youtube.com/watch?v=yS1ibDImAYU
And you can only pickup garbage that's in a similar orbit too.
In fact there's such an intercept being done soon, the mission extension vehicle (MEV) is going to rendezvous with an old but still controlled satellite in order to extend its useful life. This rendezvous is being done in the graveyard orbit in case something goes wrong.
The ESA is putting a lot of focused attention behind this very thing, to certain extents [0]
[0] https://conference.sdo.esoc.esa.int/proceedings/sdc7/paper/7...
A satellite is made out of metal and such things. You can heat that metal hot enough to melt it, but then its structural integrity will fail, and the liquid will disperse into a cloud of metal droplets while other satellite-parts drift away. When the metal droplets cool off, they will still remain in about the same orbit. This does not make an impact with any of these droplets particularly safe.
Transporting the amount of energy to properly vaporize metal is also problematic and expensive.
We do not possess tractor beam technology. Our tractors on this planet all use mechanical linkages. If we did have tractor beam technology, powering it would remain a problem.
> However, about 10 years ago, researchers found that the object may experience an optical pulling force (OPF) toward the source direction when illuminated by an unfocused beam, such as a diffraction-free (nondiffraction) Bessel beam, which is named an optical tractor beam (OTB). Although it seems counterintuitive, OPF has been theoretically proved and experimentally demonstrated within recent years, as will be reviewed in this paper.
Source: https://www.spiedigitallibrary.org/journals/advanced-photoni...
Although, there's a lot of distance to cover between the current state-of-the-art and actually capturing orbital debris.
I guess there's a hope that someday we'll figure out a way to recover and permanently de-orbit all of them.
If one can't do business without carelessly leveraging finite public resources I would argue that that business is untenable
I know, I know, the above is close to hopelessly optimistic. It's like when I was younger: I remember thinking, "I'm not going to smoke cigarettes, but if I did it would probably be okay. By the time it would really matter, medicine will have surely found cures." I was an idiot, though I never did smoke.
Public resources are always consumed while public exists. We should thrive to always experiment, learn from it and evolve/do better.
When we're talking about satellites in graveyard orbits, no humans can see it, there's no wildlife, or really any environment to damage. None of the concerns we have with litter apply. Trying to speak against it as if it's litter is then either an attempt to shoehorn a concept into a place where it doesn't apply to make a snap judgement, or a malicious attempt to attach something for other reasons. No comment on which is going on here, but if you're going to convince anybody not to enjoy the many benefits of geostationary satellites, you're going to need to make a better case than likening it to "litter".
Low Earth orbits do have atmospheric drag issues, and those items need to have fuel to replace lost velocity and restore the correct orbit.
The ISS page has a neat table of orbital height over time where you can see the burns to 'jack it back up'.
While there's a lot of space junk up there, you can see that the graveyard orbit is in fact a fairly tight line around the equator. It should be quite easy to avoid.
From the look of it, it's kinda functionally equivalent to putting a fence around an airport. I mean, sure, it theoretically limits your options, but not in any practical way.
It sounds like there's confusion about that point. The article says that the plan says that they're going to de-orbit the satellite so it can burn up on reentry, and that it will be in a graveyard orbit, which are contradictory objectives to each other. It sounds like AT&T hasn't responded yet to clarify which of the two they actually meant.
De-orbit down around usual LEO altitudes is more drag-effect, you will return to Earth soon enough anyway.
Suffice to say this is a very great distance, and the probability of a collision orbit at this distance is so phenomenally unlikely that even if left in place there is nothing to consider of this risk.
Moving to a higher and unused orbit means nothing will ever impact it in any human time horizon.
Low Earth Orbit is a bigger concern; but much of the concern in that region is spent rocket stages which have enough propellant inside them that they eventually explode and then for several months-years we have lots of debris (and then threat of a Kessler Cascade). The international community has responded to this threat by adding regulations on the proper disposal of spent rocket stages. (Occasionally, similar to this satellite, there are failed stages which do explode, but it should not happen often or on a normal path.)
http://acqnotes.com/wp-content/uploads/2014/09/Orbit-Map.png
But it's just a guess.