A SpaceX Falcon 9 rocket carrying advance GPS satellites for the Air Force is on its way to the International Space Station.
https://abc30.com/science/spacex-falcon-9-rocket-lifts-off-for-international-space-station/4956896/Glad to see the mainstream news covering this launch, but perhaps they don't have the excellent space journalists we are accustomed to seeing here in NSF. For Pete's sake, all they had to do was cut-and-paste from the press kit! Yikes!Edit to add quote from the article:QuoteA SpaceX Falcon 9 rocket carrying advance GPS satellites for the Air Force is on its way to the International Space Station.
Back to the discussion about the S2 deorbit burn: I am skeptical that a further 2 hour coast to apogee before deorbit would be used - I bet they want to finish the thing as soon as possible after payload sep. Yes, it's less efficient.But if the report that reentry was at T+6h30min is correct, and using the target NOTAM area west of Namibia,I get a much better fit with a 450m/s retrograde burn at about 1600 UTC, just after payload separation,resulting in a -590 x 17570 km deorbit trajectory. Burns of around 180 m/s at apogee instead give entryat T+7h10m further downrange near the Antarctic. But it's quite possible I've done my sums wrong.
Back to the discussion about the S2 deorbit burn: I am skeptical that a further 2 hour coast to apogee before deorbit would be used - I bet they want to finish the thing as soon as possible after payload sep. Yes, it's less efficient.But if the report that reentry was at T+6h30min is correct, and using the target NOTAM area west of Namibia, I get a much better fit with a 450m/s retrograde burn at about 1600 UTC, just after payload separation, resulting in a -590 x 17570 km deorbit trajectory. Burns of around 180 m/s at apogee instead give entry at T+7h10m further downrange near the Antarctic. But it's quite possible I've done my sums wrong.
News Release Issued: Dec 23, 2018 (11:07am EST)..."In the coming days, GPS III SV01 will use its liquid apogee engines to climb into its operational orbit about 12,550 miles above the earth. We will then send it commands to deploy its solar arrays and antennas....
From the Lockheed Martin press release in the update threadQuote from: jacqmans on 12/24/2018 07:15 amNews Release Issued: Dec 23, 2018 (11:07am EST)..."In the coming days, GPS III SV01 will use its liquid apogee engines to climb into its operational orbit about 12,550 miles above the earth. We will then send it commands to deploy its solar arrays and antennas....The satellite will only deploy the solar arrays after reaching the operational orbit, does it run on battery so long? or do the solar arrays produce some power for initial checkout even before being unfurled?(I imagine this this is routine but I never noticed it before)
Question regarding first stage ditching...if SpaceX knew in advance the total fuel requirements of the payload, could they have compensated and return the first stage to the drone ship?Or was the weight and trajectory required beyond that capability?Thank you.
\Just 100m/s of margin. I can understand why USAF wanted all the performance from F9.
Quote from: edkyle99 on 12/23/2018 02:15 pm[...] I'll note that depending on the SpaceX velocity versus altitude numbers has seemed in the past to provide underestimates of the actual orbit.Aha! I think I finally tracked down why the SpaceX cutoff numbers give different apogees than tracking reveals.[...]So the trick, I think, is to do the rotating-inertial conversion *at the 3D location of the burn*.
[...] I'll note that depending on the SpaceX velocity versus altitude numbers has seemed in the past to provide underestimates of the actual orbit.
Aha! [...]
https://www.gpsworld.com/first-gps-iii-satellite-now-available/QuoteThe U.S. Air Force Second Space Operations Squadron (2 SOPS) has issued a statement that the first GPS III satellite is available for backup. While occupying the same plane as SV-68, the new satellite is broadcasting healthy, usable signals and is an active part of the constellation in the vicinity of slot F3 near SV-68.
The U.S. Air Force Second Space Operations Squadron (2 SOPS) has issued a statement that the first GPS III satellite is available for backup. While occupying the same plane as SV-68, the new satellite is broadcasting healthy, usable signals and is an active part of the constellation in the vicinity of slot F3 near SV-68.
2020012 --------------------------SVN60 (PRN23) DECOMMISSIONING JDAY 071/2200 NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2020012SUBJ: SVN60 (PRN23) DECOMMISSIONING JDAY 071/22001. NANU TYPE: DECOMNANU NUMBER: 2020012NANU DTG: 120131Z MAR 2020REFERENCE NANU: 2020010REF NANU DTG: 042041Z MAR 2020SVN: 60PRN: 23UNUSABLE START JDAY: 069UNUSABLE START TIME ZULU: 1919UNUSABLE START CALENDAR DATE: 09 MAR 2020DECOMMISSIONING START JDAY: 071DECOMMISSIONING START TIME ZULU: 2200DECOMMISSIONING START CALENDAR DATE: 11 MAR 20202. CONDITION: GPS SATELLITE SVN60 (PRN23) WAS UNUSABLE AS OF JDAY 069 (09 MAR 2020)AND REMOVED FROM THE GPS CONSTELLATION ON JDAY 071 (11 MAR 2020).3. POC: CIVILIAN - NAVCEN AT 703-313-5900, http://HTTPS://WWW.NAVCEN.USCG.GOVMILITARY - GPS OPERATIONS CENTER AT http://HTTPS://GPS.AFSPC.AF.MIL/GPSOC, DSN 560-2541,COMM 719-567-2541, [email protected], http://HTTPS://GPS.AFSPC.AF.MILMILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3526. COMM 805-606-3526.[email protected]
