2018-001A
NGST commercial launch for US govt. Core B1043.
The first orbital launch of the year was carried out by SpaceX on Jan 8 with a secret payload called ZUMA, to be sent to low Earth orbit inclined at 50 degrees. SpaceX's contract was with the Northrop Grumman company, which was probably also the spacecraft prime contractor, and fronted for the ultimate user which is an unknown US government agency (probably the NRO, but it's always possible a new secret three-letter-agency has arrived on the scene). According to industry sources prior to launch, Northrop Grumman is known to have provided its own payload adapter instead of using the standard Falcon 9 one. A payload adapter connects the spacecraft to the final stage of the rocket and performs the actual separation of spacecraft from rocket once orbit is achieved. (Don't confuse this with the payload fairing or nosecone, which protects the spacecraft from the atmosphere). This function is normally the responsibility of the launch provider, but it is reasonable to infer that in this case payload separation was the responsibility of Northrop Grumman or of the US government customer, rather than of SpaceX.
Falcon 9 mission 48 was launched from Cape Canaveral's Pad 40 and used first stage B1043, which returned to the Cape to land at landing zone LZ1. Mission events after payload fairing separation are secret, but SpaceX later reported that the Falcon 9 did its job correctly. The second stage was expected to separate from the payload and perform a deorbit burn after about 1.5 orbits, destroying itself over the Indian Ocean. Consistent with this, a rocket burn was seen at the appropriate time by observers in Sudan.
For a successful mission I would have expected two entries in the US satellite catalog: the payload, given the bland cover name USA 280 and the international designation 2018-001A, and the rocket, which would get 2018-001B despite its short stay in orbit (the normal rule is that you get cataloged if you stay up more than one complete orbit). In the event, only one catalog entry appeared, that for USA 280. The Wall Street Journal reported, citing sources on Capitol Hill, that the mission was a failure - the spacecraft failed to separate from the upper stage and was destroyed on reentry. This scenario, if true, is consistent with the available data, including the claim that SpaceX does not think it is at fault (although a full failure investigation could always find something subtle that could change that). It would imply that the combined Zuma/Falcon Stage 2 completed its 1.5 orbits - consistent with it getting a single catalog entry - and that the second stage then was deorbited with the expensive payload still attached. Industry insiders have suggested that multiple attempts would have been made to separate the payload. It is possible that the deorbit burn was not aborted because if the payload remained in orbit attached to the stage, it would present a significant debris risk (similar to the risk used to justify the antisatellite intercept of USA 193 in 2008). If it's clear the mission is a failure, it's more prudent to carry out safe disposal of the vehicle. The `decay date' (i.e. reentry date) column in the satellite catalog has been left blank, but that is standard for secret missions which have often reentered without any acknowledgement.
Others have suggested a scenario in which the mission was a success and the failure rumours are a deliberate cover story as part of an attempt to conceal the spacecraft. I find this unlikely for two reasons. Firstly, the source of the rumours seem to be Congressional staffers who can influence the spy agencies' budgets, will be displeased with them at the hundreds of megabucks apparently lost, but will be even less pleased about being made patsies for a cover story - and they will find out. Secondly, my impression is these rumours have made amateur observers even more determined than usual to search for the satellite in order to clarify the situation, so it's highly unclear what such a cover story would actually achieve.
Satellite observer Marco Langbroek has calculated that the Sudan observation implies an orbital altitude around 1000 km; the Falcon 9 has about a 9000 kg capacity to this orbit, which sets an upper limit to the payload mass. Such an orbit makes some kind of radar satellite seem the most likely mission.
Observations of stage 2 reentry over Sudan indicate 1000 km orbit (+- 100 km). F9FT capacity to this orbit around 9000 kg. Successful (?) deorbit with payload still attached suggests mass is more likely lower.
Need 300 m/s to achieve -100 km perigee (let's guess this was intended) from 1000 km orbit. Delta V = 3380 ln (m1/m2) = 300 m/s for m2 = 3000 kg implies 280 kg prop. If only 250 m/s achieved (1+280/m) = 1.077 so 280/m = 0.077 so m = 3600, implying very light payload. To deorbit 11000 kg payload+stage with this prop only get 91 m/s With 9000 kg get 111 m/s
Reverse argument: if deorbited, used 250 m/s. Assume this was with 6000 kg payload so 9000 kg overall. dV = 250 = 3380 ln (1+x/9000) so about 700 kg of prop needed.
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| Zuma |
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| Date | Time | Event | Orbit |
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| 2018 Jan 8 | 0100 | Launch by Falcon 9 | CC LC40 |
| | | T+2:16 MECO |
| | 0102 | T+2:19 St 1 sep |
| | | T+2:21 Stage 2 burn |
| | | T+2:30 Boostback burn |
| | | T+3:08 Fairing |
| | | T+6:09 Entry burn |
| | 0108 | T+7:51 Stage 1 land LZ1 |
| | 0110? | Stage 2 SECO |
| | | Payload failed to sep? |
| | 0315? | Stage 2 deorbit over Sudan |
| | 0330? | Stage 2 entry over Indian Ocean |
