DirecTV 4s

[slice1900]

Probably. But how much will it build up over the next hundred, two hundred years?

There are only so many GSO satellites you can have at once, because of the way they're licensed in certain slots. And given that they last 20 years each, you're only talking about a couple thousand a century. Likely not all at the same altitude and not necessarily orbiting exactly around the equator (I don't know what 'rules' there are for how to park them) You'd need a lot more time than that for them to become a problem. Heck if they are all orbiting aroudn the equator it is pretty easy to avoid them - when leaving the Earth go don't leave exactly along the equatorial plane. They probably never do because their intended destination is probably never exactly along the equatorial plane, so they don't even need to consider the GSO & parked satellites because the craft isn't coming near where they are.

Like I said, LEO is much worse problem today and it will be far worse as time goes on. We'll probably have to think of a solution for it before 100-200 years go by, meanwhile the parking/graveyard orbit for GSO satellites will continue to not be any sort of issue for anyone.

 

[goaliebob99]

. In addition, DIRECTV has assessed fuel gauging uncertainty and this budgeted propellant provides an adequate margin of fuel reserve to ensure that the disposal orbit will be achieved despite such uncertainty.

This pretty much spells out that the satellite could be leaking gas or used more than they were aware of if DirecTV doenst know how much gas is in the tank, but they know that they have enough to kick it to the trashcan.

 

[HoTat2]

This pretty much spells out that the satellite could be leaking gas or used more than they were aware of if DirecTV doenst know how much gas is in the tank, but they know that they have enough to kick it to the trashcan.

But I would think any possible undetected fuel leaks notwithstanding, T4S's fuel supply minus the max. tolerance of the guaging system should still be telemetered back via TT&C to let DIRECTV know how much of a margin in fuel supply remains before reaching the disposal reserve.

So they should never allow that margin to drop too far as to allow the total fuel supply to ever come close to the disposal fuel reserve level.

Sent from my LM-V405 using Tapatalk

 

[slice1900]

That 'fuel gauge uncertainty' might be why they chose the specific license extension they did (through early next year) back in 2011. That was their "worst case scenario" for having enough fuel left to still reach their intended disposal orbit.

They may have re-assessed it more recently and found it has a few years of life left in it, and someone else has a use for it. If they've sold it to someone else that would explain why it is busy moving east instead of going directly into disposal orbit. If someone else now owns it, there wouldn't be an FCC filing for the move. Whoever owns it would do the filing under their own country's satellite authority.

The only other alternative is that Directv is moving it east before raising its orbit for disposal. Not sure why you'd do that, but maybe there are reasons why you would - i.e. if they think it is leaking they might want to put it in a disposal orbit that's as far from others as possible since the leak would cause it to slowly move. I imagine there are probably not a lot of satellites in a disposal orbit exactly over the middle of the Atlantic... Still, I would have expected some sort of filing for that eastward pre-disposal move.

There's an older filing for the satellite where they say they can't meet some new FCC regulation about venting remaining propellant after reaching disposal orbit because the satellite is of an older design that can't do that. Presumably more recently built satellites are required to do so.

 

[navychop]

Keep in mind, disposal orbits are a bit beyond geo. They move slowly. And slowly away from the earth.


Sent from my iPhone using Tapatalk

 

[nelson61]

The future for out of fuel satellites

Northrop's satellite refueling spacecraft launches on October 9th

 

[HoTat2]

The future for out of fuel satellites

Northrop's satellite refueling spacecraft launches on October 9th

Very interesting;

Not only in these "MEV" satellites ability to reach and refuel other satellites at GEO altitudes.

But somehow able to do it even for satellites that were not built for in-orbit refueling to begin with.

Sent from my LM-V405 using Tapatalk

 

[nelson61]

Very interesting;

Not only in these "MEV" satellites ability to reach and refuel other satellites at GEO altitudes.

But somehow able to do it even for satellites that were not built for in-orbit refueling to begin with.

Sent from my LM-V405 using Tapatalk

Apparantly it straps on and stays hooked up until the satellite reaches end of mechanical life and then can detach and hook on to another satellite

Sent from S10 Plus
using the SatelliteGuys app!

 

[HoTat2]

Apparantly it straps on and stays hooked up until the satellite reaches end of mechanical life and then can detach and hook on to another satellite

Sent from S10 Plus
using the SatelliteGuys app!

Oh ... well I guess that makes it a little more understandable.

As the MEV after docking (or physically "strapping" itself as you say) to the satellite must have some kind of robotic refueling probes that actually drill into or otherwise puncture the fuel tanks of the satellite and can supply fuel as long as it remains attached.

I thought it could somehow refuel a satellite and then move on to another like a spaceborne refueling truck ...

Sent from my LM-V405 using Tapatalk

 

[navychop]

Or it just holds on while using its own station keeping thrusters.


Sent from my iPhone using Tapatalk

 

[slice1900]

Its an interesting idea, but a 20 year old satellite is often quite out of date so you may want to replace it for other reasons, or some of its equipment is failing. Directv wouldn't have been interested in refueling D4S, D8 and D9S because they don't have dedicated beams to PR and Hawaii, and would supply five fewer national transponders once the need for spotbeams at 101 goes away before long. Who knows what might be wrong with them, what kind of shape the batteries are in, etc.

I suppose if they want to extend the life of their satellite offering when some of the older satellites at 99/103 start running out of fuel in ~2030 this might be a less expensive option to consider assuming they don't have other issues.

One of those "grabber" satellites would be handy to have if a satellite had a total failure while in GSO, and risked becoming a hazard to other GSO satellites someday. It could get raised up to the graveyard orbit, then the grabber can let go and go to its next mission.

 

[nelson61]

Or it just holds on while using its own station keeping thrusters.


Sent from my iPhone using Tapatalk

I'll guess that's it. I had read that the older satellites had the fill valves wire strapped or sealed so they could not open

Sent from S10 Plus
using the SatelliteGuys app!

 

[doctor J]

D4s still in lower orbit. Continuing 1.7 degrees east daily.
Presently at 81.9087 W

 

[HoTat2]

And DIRECTV files for 30-day STA extensions on two earth sations (one at the Bakersfield LADF and the other at the CRBC) to complete the deorbiting of T4S.

So I guess that definitely confirms that T4S is not being transferred to another service. But still beats the heck out of me how DIRECTV is going about moving T4S to a disposable orbit this way.

Was hoping the STA documents would make some mention of these weird maneuvers. But nothing ...

Notify going to License

Notify going to License

Sent from my LM-V405 using Tapatalk

 

[CycloneSat]

What’s T4S’s permanent resting position, and has it arrived there?

 

[nelson61]

What’s T4S’s permanent resting position, and has it arrived there?

It is no longer geostationary so it will forever appear to be continually moving , at some altitude other than geostationary

Sent from S10 Plus
using the SatelliteGuys app!

 

[doctor J]

D4s still in lower orbit. Continuing 1.7 degrees east daily.
Presently at 76.8919 W

Doctor j

 

[slice1900]

Tom Speer posted a good theory about what is going on with D4S. He suggested they were moving it eastward before raising its orbit to allow them to track it across the US in its graveyard orbit.

FCC filings bear this idea out, they filed two STAs for earth stations to use for D4S's deorbit, Bakersfield and Castle Rock. Castle Rock's writeup said it could see as far as 40W, and Bakersfield can see as far as 170W. So in a little under three weeks you'd expect to see it raise its orbit above GSO before it reaches 40W, and then first Castle Rock then Bakersfield can track it as it moves west until it reaches about 170W. That should be long enough to insure it is in a stable and proper graveyard orbit, and send commands to tweak it if necessary. Once it is retired in the graveyard orbit per FCC/ITC regulations its no longer their responsibility and they can ignore it.

 

[doctor J]

Weekly D4s update:

Still at 35,632 x 35,679 Km (Lower) orbit and still moving East at ~ 1.7 degrees per day
Todays TLE has it at 68.56 W at this moment.
Will be at it's Tracking EAST limit by November 1, 2019 (40 degree W Longitude).

Doctor j

 

[nelson61]

Last epoch shows elevation increasing from ~ -130 to ~ -80 km from GEO orbit and is located ~55 ish west