It will be ~46 deg F tonight at 8 PM EST at the Cape. ~50 tomorrow and ~60 SundaySpaceX may be waiting for the weather to warm up. Sounds odd, to be honest, but could that be a contributor?
On a. Rief glance I didn’t find the launch window for tomorrow’s launch
00:01:10 Max Q (moment of peak mechanical stress on the rocket)00:02:16 1st stage main engine cutoff (MECO)00:02:19 1st and 2nd stages separate00:02:21 2nd stage engine starts00:02:30 1st stage boostback burn begins00:03:08 Fairing deployment00:06:09 1st stage entry burn begins00:07:51 1st stage landing
00:01:16 Max Q (moment of peak mechanical stress on the rocket)00:02:20 1st stage main engine cutoff (MECO)00:02:24 1st and 2nd stages separate00:02:25 2nd stage engine starts00:02:33 1st stage boostback burn begins00:03:08 Fairing deployment00:06:15 1st stage entry burn begins00:07:56 1st stage landing
Everyone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example: SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landingBut what if the mission did not even exist before then?
Could these time differences indicate that Falcon 9 will fly a more flattened trajectory?I ask that because the new MECO time is four seconds later than the original time (140 seconds compared to 136 seconds).
Quote from: ZachS09 on 01/06/2018 08:37 pmCould these time differences indicate that Falcon 9 will fly a more flattened trajectory?I ask that because the new MECO time is four seconds later than the original time (140 seconds compared to 136 seconds).The adjusted times could be trajectory related or related to month of year of launch. Winter months produce a thicker lower atmosphere and thus the rocket has to work harder to get through it. Shuttle compensated for this by having "winter SRBs" that had their prop poured in a configuration to produce greater thrust but shorter burn time. As Flacon 9 is a liquid rocket, a longer burn time for a winter month launch mission would make sense. And given the atmospheric setup over Florida of the last week, this might be the case.
Quote from: LouScheffer on 01/04/2018 03:19 pmEveryone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example: SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landingBut what if the mission did not even exist before then? Except that our article clearly says Zuma's launch contract was established in 2015. https://www.nasaspaceflight.com/2018/01/spacex-falcon-9-launch-clandestine-zuma-satellite/
According to source documentation, Zuma’s launch contract – which did not specify a launch date – was established with SpaceX in 2015.
The adjusted times could be trajectory related or related to month of year of launch. Winter months produce a thicker lower atmosphere and thus the rocket has to work harder to get through it. Shuttle compensated for this by having "winter SRBs" that had their prop poured in a configuration to produce greater thrust but shorter burn time. As Flacon 9 is a liquid rocket, a longer burn time for a winter month launch mission would make sense. And given the atmospheric setup over Florida of the last week, this might be the case.
Quote from: ChrisGebhardt on 01/06/2018 09:16 pmQuote from: LouScheffer on 01/04/2018 03:19 pmEveryone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example: SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landingBut what if the mission did not even exist before then? Except that our article clearly says Zuma's launch contract was established in 2015. https://www.nasaspaceflight.com/2018/01/spacex-falcon-9-launch-clandestine-zuma-satellite/Again, I don't think this is a contradiction. Your article states (bold mine):QuoteAccording to source documentation, Zuma’s launch contract – which did not specify a launch date – was established with SpaceX in 2015.For a first pass at a responsiveness test, Agency X might grant SpaceX a contract for a booster, and a launch, but nothing else - no payload specified, no date, no orbit, maybe not even which coast. Then, for example, on 1 November 2017, they call up and say "Here's your payload , name is ZUMA. Here's the orbit we want. Get it into orbit within 30 days."This is exactly consistent with what we saw, your article, and the NAS report from 2010 recommending the Air Force set up responsiveness objectives. It explains why we heard nothing from SpaceX before 1 November - they did not know. And (my opinion only) this seems like very reasonable first pass at responsiveness by the government.
Quote from: whitelancer64 on 01/03/2018 05:16 pmA full WDR would do the exact same things as a static fire except light the engines. And that is in fact a MAJOR difference.A WDR doesn't require the services of the range. In this case the WDR was a propellant loading test. IMO it is a safe guess that SpaceX only partially loaded the vehicle and didn't even bother pressurizing the tanks to flight pressure.A Static Fire does require the range because a static fire is considered to be a potential launch, coming with all the hazards that are associated with an actual launch, such as having a fully fueled and fully pressurized vehicle.
A full WDR would do the exact same things as a static fire except light the engines.
Is it just me or do the landing legs look different?
Quote from: yokem55 on 01/07/2018 02:44 pmIs it just me or do the landing legs look different?Maybe its just lighting condition, but those really look flatter and missing the sharp triangular (cutaway by spin axes) outer 'crest'.
...targeting the orbital plane of USA 276 has become viable near the end of the 1:00 - 3:30 UT launch window. The orbital plane of USA 276 passes over the launch site near 3:38 UT on January 8th.
However, the launch window is only 01:00 to 03:00 UTC, not 03:30 UTC, correct?