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General Discussion => Live Event Section - Latest Space Flight News => Topic started by: Galactic Penguin SST on 01/07/2017 02:59 am

Title: Possible satellite collision alert for 7 January 2017
Post by: Galactic Penguin SST on 01/07/2017 02:59 am
This notice has been placed on the Space Track website of the Joint Space Operations Center. I've never seen such a terse alert from them before!  :o

The JSpOC has identified a close approach between two non-maneuverable satellites in a sun-synchronous orbit (approximately 800km altitude) with a time of closest approach at 21:53:00 UTC (16:53 EST) on 7 January 2017. The probability of collision has been predicted as high as 44%. Affected operators have been notified.

I guess the hints are enough for somone to calculate which is which?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: catdlr on 01/07/2017 03:14 am
This notice has been placed on the Space Track website of the Joint Space Operations Center. I've never seen such a terse alert from them before!  :o

The JSpOC has identified a close approach between two non-maneuverable satellites in a sun-synchronous orbit (approximately 800km altitude) with a time of closest approach at 21:53:00 UTC (16:53 EST) on 7 January 2017. The probability of collision has been predicted as high as 44%. Affected operators have been notified.

I guess the hints are enough for somone to calculate which is which?


Try this site:
http://celestrak.com/cgi-bin/searchSOCRATES.pl?IDENT=NAME&NAME_TEXT1=&NAME_TEXT2=&ORDER=MINRANGE&MAX=10
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Bubbinski on 01/07/2017 05:25 am
Are these active satellites performing missions? And would the Falcon 9 Iridium satellites get up to the 800 km altitude where the collision might occur?

Edited: would the A-Train satellites be affected as well if the worst happens?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Jarnis on 01/07/2017 05:29 am
Are these active satellites performing missions? And would the Falcon 9 Iridium satellites get up to the 800 km altitude where the collision might occur?

Edited: would the A-Train satellites be affected as well if the worst happens?

"Non-manouverable" would imply that they're non-functioning, or are there sats that high up with zero maneuvering capability?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: zubenelgenubi on 01/07/2017 06:49 pm
This notice has been placed on the Space Track website of the Joint Space Operations Center. I've never seen such a terse alert from them before!  :o

The JSpOC has identified a close approach between two non-maneuverable satellites in a sun-synchronous orbit (approximately 800km altitude) with a time of closest approach at 21:53:00 UTC (16:53 EST) on 7 January 2017. The probability of collision has been predicted as high as 44%. Affected operators have been notified.

I guess the hints are enough for somone to calculate which is which?


Try this site:
http://celestrak.com/cgi-bin/searchSOCRATES.pl?IDENT=NAME&NAME_TEXT1=&NAME_TEXT2=&ORDER=MINRANGE&MAX=10
Has anyone determined which satellites?  I followed the link catdlr provided and found no conjunctions meeting the timing that GP's OP provided.

EDIT: Till Potinius on Seesat-l posts (http://www.satobs.org/seesat/Jan-2017/0038.html), using Celestrak:
Quote
OPS 4412 (00801) - NOAA 16 DEB (41428) with 1km Min Range at 2017 Jan 07 21:53:54.734.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: input~2 on 01/07/2017 07:27 pm
T.S. Kelso ‏@TSKelso  4 h
.@till_83 Event appears to involve DMSP F15 & METEOR 1-26. Can’t confirm prediction; no public TLEs for F15. McCants data is from Day 313.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Bubbinski on 01/07/2017 07:36 pm
Where over earth would those 2 satellites be when they encounter each other? If it's over the night side I suppose people might get a little sky show if they look up. (Where I am it would be 2:53 pm, a little over an hour from now, and it's cloudy here to boot).
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Orbiter on 01/07/2017 08:06 pm
Looking at the current TLE's for METEOR 1-26 it could place the potential collision over Antarctica in approximately 47 minutes.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: IanThePineapple on 01/07/2017 08:21 pm
What programs/sites can we use to see if this happens?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Flying Beaver on 01/07/2017 08:49 pm
What programs/sites can we use to see if this happens?

U.s. military is tracking it and will confirm if it happens.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Bubbinski on 01/07/2017 09:09 pm
Was looking at n2yo.com after a Google search. The Meteor satellite would be flying over the Indian Ocean now on a northward track that will take it past Calcutta, India and Bangladesh. I suppose that would be the first opportunity for land based observers to see if anything happened to it. Its track would also take it past northern Yukon just before it enters daylight.

The DMSP satellite is heading northward over the South Pacific in daylight, it'll be over northern Alaska when it enters darkness.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Pelf on 01/07/2017 10:15 pm
Satellites missed each other: https://twitter.com/Spaceflight101/status/817871225259249664
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: enzo on 01/08/2017 04:07 am
What monetary value would the US military place on a collision like this? I.e., is it higher than the cost of developing a mitigation strategy?
By mitigation strategy I mean some kind of ready-to-launch lightweight device which would match the satellite's orbit, rendezvous and give it a nudge. Or a giant pillow...whatever works.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: FutureSpaceTourist on 01/08/2017 05:48 am
Quote
@coastal8049 @Itzalpean TCA with the old TLE was within 3 seconds to the time given by JSpOC. Miss distance 10.04km

https://twitter.com/spaceflight101/status/817885494134657026 (https://twitter.com/spaceflight101/status/817885494134657026)
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: savuporo on 01/08/2017 07:17 am
By mitigation strategy I mean some kind of ready-to-launch lightweight device ..
Operationally responsive launch does not exist.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: sdsds on 01/08/2017 07:22 am
By mitigation strategy I mean some kind of ready-to-launch lightweight device ..
Operationally responsive launch does not exist.

Operationally responsive orbital launch does not exist. It isn't clear that a mitigation device would need to reach orbit....
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: savuporo on 01/08/2017 07:40 am
By mitigation strategy I mean some kind of ready-to-launch lightweight device ..
Operationally responsive launch does not exist.

Operationally responsive orbital launch does not exist. It isn't clear that a mitigation device would need to reach orbit....

Eh ? You either
- have to match target velocity pretty closely, which by definition places you on orbit
- or you are talking about kinetic ASAT weapon

What other possibilities are there ?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: sdsds on 01/08/2017 08:31 am
Impact could be a possibility though your point is taken: adding energy and general chaos to the situation might not be a good thing in every circumstance!

Could there be mitigation devices that approach at high relative speed but don't cause the target to shatter into a million pieces? Just as a straw man proposal, what about dispersing a cloud of tiny styrofoam impactor beads? Could that alter the orbit of the target without causing its disintegration?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: as58 on 01/08/2017 08:41 am
Previously stated 'probability of collision as high as 44%'  and miss distance of ~10 km seem to me kind of at odds with each other. Or doesn't the miss distance mean what I think it does (=closest actual approach distance)?
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: AncientU on 01/08/2017 12:04 pm
What monetary value would the US military place on a collision like this? I.e., is it higher than the cost of developing a mitigation strategy?
By mitigation strategy I mean some kind of ready-to-launch lightweight device which would match the satellite's orbit, rendezvous and give it a nudge. Or a giant pillow...whatever works.

If the lateness of this alert is typical of the capabilities of prediction, the only realistic mitigation strategy is debris removal... systematically, over a period of years that is.  (A.K.A, Planning ahead.) 

Otherwise, we'll be spectators as we were yesterday. 

Oh, maybe we can all cross our fingers, too, and hope the cascade doesn't trigger.  Sounds affordable.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Rocket Science on 01/08/2017 12:19 pm
No worries Agent 86 was on top of it...
https://www.youtube.com/watch?v=oPwrodxghrw
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Comga on 01/09/2017 04:25 am
There are several threads with amature and professional concepts for deorbiting defunct satellites and space debris.
Can we keep this thread on this and other potential collisions and leave those discussions in those threads?


Edit: From Spaceflight101 (http://spaceflight101.com/close-orbital-encounter-january-7-2017/):

The publicly available SOCRATES conjunction assessment tool processes orbital data from all non-classified objects and shows a conjunction between the Transit 9 satellite and a piece of NOAA-16 debris at 21:53:54 UTC and analysis of non-public data shows possible candidate encounters between the DMSP F9 & OPS 3367A satellites and a potential head-on collision of DMSP F15 & Meteor 1-26 over Antarctica.

DMSP F15 and Meteor 1-26 appear to the the prime candidates for the encounter.

The 1,220-Kilogram DMSP F15 was launched in 1999 atop a Titan II rocket to join the Defense Meteorological Satellite Program as the first Block 5D3 satellite. Meteor 1-26 is a Soviet-era weather satellite orbited in 1976 with a launch mass around 2.2 metric tons.

Based on available orbital data, the two satellites will have a very close encounter at 21:53 UTC on Saturday, some 870 Kilometers above Antarctica. If a collision occurs between these two, it will be mostly head-on – creating the highest possible relative velocity between the two objects.

edit 2:  DMSP-15 is one of that series that has NOT had a battery explosion. 
People have discussed deorbiting DMSP satellites.  We were told that the Air Force has no interest in or budget for doing that.
Title: Re: Possible satellite collision alert for 7 January 2017
Post by: Lar on 01/09/2017 02:18 pm
Stay on topic for this particular collision alert. A mod report suggested a lock, but there may be more to this... if additional data comes out that is specific to this, great.

General strategies belong elsewhere.

thanks