Can satellites be serviced?

[TV Junkie]

TV Junkie. Thanks you for getting the you tube vidio. Now people will know I wasn,t just talking thru my hat. I still hope that others will do thier research to Northrop gruman about satelite servicing.

I don't think folks would think that of you my friend!!

 

[navychop]

Yes, there is interest in a standardized attachment point on satellites for recovery, servicing, disposal etc. Same for refueling ports (which pretty much requires that attachment point). Different fuels may be used, but not that many. Oxygen would be common and can be one standard port. Not all fuel used by satellites for station keeping require oxygen. Some (most?) self ignite using chemically bound oxygen in the fuel itself.

 

[TheKrell]

Some (most?) self ignite using chemically bound oxygen in the fuel itself.

Hypergolic propellants use 2 components that ignite when mixed. Is that what you mean? Or one propellant that decomposes via a catalyst?

 

[harshness]

Northrop Grumman is already servicing satelites.

The satellite isn't really being "serviced" (refueled) as much as it is having its drive system replaced by the self-piggybacking MEV. Launch a smaller bird to salvage a larger bird.

I see the MEP as a future and the MEV as more of a proof-of-concept but they'll have to figure out whether restoring some of the old birds is really worth it given that many of them (especially the ones that cover something other than ocean as the Intelsat was) may be looking for more confined beams (as Bell Satellite TV has done with their latest bird that reduced US coverage significantly).

Given that the MEVs are the only satellites currently designed for refueling, actual repairs/refurbishments are still quite a ways off.

 

[NYDutch]

I would only point out that certain low altitude high value satellites have indeed been serviced. Cases I can think of off the top of my head include Hubble and multiple space stations. Anybody remember Skylab?

There are those rare few of course, and some other physically serviceable sats appear to be on the horizon, but overall sats are still not physically serviceable in situ. Especially the high altitude DBS sats.

 

[navychop]

Hypergolic

I couldn’t remember the word when I posted.

 

[TheKrell]

I couldn’t remember the word when I posted.

I am wondering what's happening to me, and more specifically my memory, as I age. As you may note in various SG threads, I'm popping up with info from decades ago, and which I haven't thought about in years. Are these old memories replacing more recent ones?

 

[Ethan13]

There are those rare few of course, and some other physically serviceable sats appear to be on the horizon, but overall sats are still not physically serviceable in situ. Especially the high altitude DBS sats.

Do you think that the possibility of servicing satellites could greatly reduce the likelihood of Kessler syndrome in orbit? Or is it better to come up with other ways to solve the problem for this?
I saw the strange news recently about the development of a wooden satellite by a Japanese company. wood will burn faster in the atmosphere, but there are also electronics and fuel residues.

 

[Ethan13]

Space company London has successfully tested its space tug.
This device can restart the engine in orbit several times.
The space tug will allow you to remove space debris.
Here is the article:
Successful Fife rocket tests could hold key to solving the space junk problem .
It also says that the launch is scheduled for 2023.
How promising do you think this technology is?
It seems beautiful to me.

 

[NYDutch]

Do you think that the possibility of servicing satellites could greatly reduce the likelihood of Kessler syndrome in orbit? Or is it better to come up with other ways to solve the problem for this?
I saw the strange news recently about the development of a wooden satellite by a Japanese company. wood will burn faster in the atmosphere, but there are also electronics and fuel residues.

The possibility of the Kessler effect occurring is primarily a LEO issue rather than the higher elevations, but as collision avoidance systems keep advancing, such as those used in the Starlink sats, the probability decreases. I do recall seeing something about the Japanese wooden satellite, but I don't know enough about the details to fully understand the operational concept. Starlink sats have proven that complete destruction on re-entry is achievable without going to that extreme.

 

[TheKrell]

I'm having trouble Googling Starlink and collision avoidance systems. Do you have a reference?

 

[NYDutch]

I'm having trouble Googling Starlink and collision avoidance systems. Do you have a reference?

There's a pretty good explanation here:

Starlink's autonomous collision avoidance

On their website, SpaceX claims that Starlink satellites are able to conduct autonomous collision avoidance manoeuvres using alerts from the US Department of Defence. This seems very reasonable, gi...

space.stackexchange.com

 

[TheKrell]

There's a pretty good explanation here:

Starlink's autonomous collision avoidance

On their website, SpaceX claims that Starlink satellites are able to conduct autonomous collision avoidance manoeuvres using alerts from the US Department of Defence. This seems very reasonable, gi...

space.stackexchange.com

Well, that's confusing. Your ref says it will be done on the ground using DoD SpaceTrack data, rather than making each satellite figure it out. What's "autonomous" about that?

SpaceX somewhere must be receiving this information and determining when to make a maneuver. There's no way this is done on every satellite, it's complex work, and easier done on the ground.

 

[NYDutch]

Well, that's confusing. Your ref says it will be done on the ground using DoD SpaceTrack data, rather than making each satellite figure it out. What's "autonomous" about that?

My take is that the heavy computing for each sat will be done on the ground with the results uploaded for independent action as needed. Maybe "semi-autonomous" would be a better descriptor. I see it as similar to our vehicle GPS where regular updates are transmitted to advise us of traffic conditions ahead, but it's up to the local navigation system (me in this case) to determine and take any needed actions such as lane changing, rerouting, etc. to avoid delays.

 

[telstar_1]

Wow, sats trying to avoid each other as well as 60 years of space debris. The amount of stuff we're putting up there only seems to be exponentially increasing. The idea of servicing satellites has mostly fallen through simply because better and better technologies become available for new launch. It's also of course an incredibly expensive undertaking, as would be the idea of launching a vehicle to try to retrieve old space hardware and return it safely to the earth.

We're filling the space around our planet up with speeding bullets, a few of which have actually collided, while there has for years been prediction of an eventual tipping point wherein collisions increase in frequency, creating thousands more bullets with each strike to create such dense shrapnel that may render certain orbits practically unusable, as well as being practically impossible to clean up. Is that the Kessler Effect described?

I have variously heard these minisats being described in glowing terms as a boon to mankind, technically interesting, etc., but don't they simply represent loading the gun up with more and more whizzing bullets?

 

[navychop]

From what I read, if we stopped all launches, in 3-5 years, essentially all LEO garbage would be gone.

 

[NYDutch]

Wow, sats trying to avoid each other as well as 60 years of space debris. The amount of stuff we're putting up there only seems to be exponentially increasing. The idea of servicing satellites has mostly fallen through simply because better and better technologies become available for new launch. It's also of course an incredibly expensive undertaking, as would be the idea of launching a vehicle to try to retrieve old space hardware and return it safely to the earth.

We're filling the space around our planet up with speeding bullets, a few of which have actually collided, while there has for years been prediction of an eventual tipping point wherein collisions increase in frequency, creating thousands more bullets with each strike to create such dense shrapnel that may render certain orbits practically unusable, as well as being practically impossible to clean up. Is that the Kessler Effect described?

I have variously heard these minisats being described in glowing terms as a boon to mankind, technically interesting, etc., but don't they simply represent loading the gun up with more and more whizzing bullets?

Starlink LEO sats will de-orbit and burn up in a few years even if not functioning. I can't speak to the other LEO sats as far as burning up, but all of them will de-orbit much faster than mid or high altitude sats. There's enough gravity pull to make sure they come down at some point. LEO sats are similar to airplanes in that launches are optional, landings are mandatory.

 

[TRG]

I am wondering what's happening to me, and more specifically my memory, as I age. As you may note in various SG threads, I'm popping up with info from decades ago, and which I haven't thought about in years. Are these old memories replacing more recent ones?

I know the feeling. I can't remember what I had had for breakfast some days but complex physics and formulas from years ago are clear as a bell. Hopefully that doesn't equate to alsheimers or something equally as mentally debilitating.

 

[TRG]

From what I read, if we stopped all launches, in 3-5 years, essentially all LEO garbage would be gone.

Hmmm... Not sure about that. There is space junk that is decades old in low earth orbit.

I once had an equatence now deceased that worked at NORAD. They track thousands of small materials in orbit. Everything from paint chips to dislodged bolts. Some of that material isn't expected to re-enter the atmosphere for a long, long time.

 

[TheKrell]

There's enough gravity pull to make sure they come down at some point.

It's not the gravity, but rather the drag from the extremely rarified air up there. That drag depends on the density of the satellite. Nuts and bolts will probably (my wag) stay up there much longer than a big satellite with large solar panels to drag it down.