Re: DirecTV races to decommission broken Boeing Spaceway-1 satellite

From: Michael R Thompson via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 31 Jan 2020 05:04:43 +0000
SPACEWAY-F1 is on the move.

TLEs on the 29th and 30th show two maneuvers: The first to put it 23km above GEO, and the second to put it 58km above. Now drifting westward.

Michael
________________________________
From: Michael R Thompson <thomp376_at_purdue.edu>
Sent: Friday, January 24, 2020 8:20 PM
To: tme_at_asteroidinitiatives.com <tme_at_asteroidinitiatives.com>; SeeSat List <seesat-l_at_satobs.org>
Subject: Re: DirecTV races to decommission broken Boeing Spaceway-1 satellite

Hi Marshall,

I'm keeping an eye on it.  It made a normal stationkeeping maneuver yesterday, but has not started to raise its orbit yet.  They might have done something a little bit weird to use extra fuel, but it might just be a glitch in the TLE.

I'd imagine they're waiting for a response from the FCC.  If they're cleared to leave fuel on board, there's still plenty of time to get to the graveyard orbit.

Personally, I'd like to see them put it up higher.  Ran the numbers the other day and I think they could get to a circular orbit 1000km above the GEO belt, and that would use up nearly all of their fuel.  There's some uncertainty in that number for sure, but they can definitely get it above the standard graveyard to use up more fuel before passivizing.

Thanks,
Michael
________________________________
From: Seesat-l <seesat-l-bounces+thomp376=purdue.edu_at_satobs.org> on behalf of Marshall Eubanks via Seesat-l <seesat-l_at_satobs.org>
Sent: Friday, January 24, 2020 7:01 PM
To: Seesat-L <seesat-l_at_satobs.org>
Subject: DirecTV races to decommission broken Boeing Spaceway-1 satellite

https://arstechnica.com/information-technology/2020/01/directv-races-to-decommission-broken-boeing-satellite-before-it-explodes/

Time is a factor -

DirecTV races to decommission broken Boeing satellite before it explodes

which contains this

Under the standard process for taking satellites out of their normal
orbits, "Spaceway-1 would complete its end-of-life maneuvers and then
discharge all remaining bipropellant prior to decommissioning the
spacecraft," DirecTV wrote.

But because of the explosion risk, there isn't enough time to fully
deplete the bipropellant. That's why DirecTV asked for a waiver from the
rules.

"Waiver is appropriate in this case because grant would not undermine
the purpose of the rule, which is to reduce the risk of accidental
explosion," DirecTV wrote. The waiver "will reduce the potential for
harm to other geostationary satellite operators," DirecTV said.

DirecTV said it intends to discharge as much fuel as possible before
completing the move but that "the priority remains the complete
decommissioning of the satellite prior to commencement of the spring
eclipse season to limit the risk of an accidental explosion." In the
time available, DirecTV said "it will be able to deplete only a nominal
portion of the approximately 73kg of bipropellant remaining onboard
Spaceway-1." Fully depleting the bipropellant would take two or three
months.

"Delayed de-orbit maneuvers or prolonged propellant depletion strategies
are not possible given the heightened likelihood of catastrophic failure
of the Spaceway-1 satellite should the damaged battery be recharged,"
the filing said.

DirecTV described its plan as "de-orbiting" and moving the satellite
into a "disposal orbit," which would suggest bringing it closer to Earth
and letting it burn up in the atmosphere. But the filing also says the
new orbit will be "300km above the geostationary arc," which would make
it a graveyard orbit. Assuming that's the case, Spaceway-1 would remain
indefinitely in an orbit that's well above other geostationary
satellites. We've asked AT&T for clarification on this point.

DirecTV asked for a 30-day waiver "beginning no later than January 20,
2020," so it may have already received permission and begun the
operation, which is expected to take 21 days. We contacted DirecTV owner
AT&T and the FCC about the status of the waiver request this morning and
will update this article if we get any response.

-----
I feel sure this satellite will be going up not down - but does anyone
know if this movement has begun?

Regards
Marshall
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Received on Thu Jan 30 2020 - 23:05:54 UTC

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