Re: Zuma pre-launch elements

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 15 Nov 2017 10:30:06 +0100
The Zuma launch has been postponed by a day, to early Friday the 17th, 1:00 - 3:00 UT.

- Marco

https://spaceflightnow.com/2017/11/15/falcon-9-zuma-mission-status-center/
Verstuurd vanaf mijn iPad

> Op 14 nov. 2017 om 22:59 heeft Ted Molczan via Seesat-l <seesat-l_at_satobs.org> het volgende geschreven:
> 
> Zuma is scheduled for launch from Cape Canaveral on a Falcon 9 v1.2 on 2017
> Nov 16, during a roughly two hour launch period that opens at 01:00 UTC. 
> 
> I have not done much research on this launch. There has been considerable
> discussion on NasaSpaceflight.com, which I have read through. The launch was
> procured by Northrop Grumman on behalf on an unspecified U.S. government
> customer. The NRO reportedly has denied ownership, but in my opinion that
> does not preclude a mission on behalf of the NGA or NSA.
> 
> Spaceflight Now will cover the launch:
> 
> https://spaceflightnow.com/
> 
> The ascent NOTAM suggests a trajectory very similar to that of NROL-76,
> which launched USA 276 (17022A / 42689) into a 50 deg orbit. USA 276
> subsequently made a number of close fly-bys of ISS. The second stage
> de-orbit NOTAMs is consistent with a quasi-50 deg orbit, with de-orbit
> occurring about 3.5 h after launch.
> 
> The following orbital elements assume launch at 01:00 UTC, into an orbit
> similar to the initial orbit of USA 276:
> 
> Zuma                                                     391 X 412 km
> 1 74301U 74301A   17320.04166668  .00011340  00000-0  15763-3 0    07
> 2 74301  50.0032 323.7956 0015627 353.6173  21.6500 15.55612078    05
> 
> Below are lower and higher altitude variants, to help bracket initial
> searches:
> 
> Zuma                                                     293 X 314 km
> 1 74302U 74302A   17320.04166669  .00011340  00000-0  15763-3 0    00
> 2 74302  50.0032 323.7956 0015627 353.6173  21.1500 15.90000000    06
> 
> Zuma                                                     496 X 517 km
> 1 74303U 74303A   17320.04166669  .00011340  00000-0  15763-3 0    02
> 2 74303  50.0032 323.7956 0015627 353.6173  22.1500 15.20000000    01
> 
> Inclination and RAAN could be off by at least a few degrees.
> 
> Launching at about 01:32 UTC would enable matching the RAAN of USA 276,
> 331.9 deg. That is an observation, not a prediction; meaningless
> coincidences and near coincidences involving orbits arise frequently.
> 
> Once Zuma's orbit is known, it will be possible to check for close
> encounters with ISS. I have no reason to expect any relationship to ISS, but
> it would not hurt to check.
> 
> For launch at 01:00 UTC, an evening northern hemisphere visibility window
> would open several days after launch. Southern hemisphere observers would
> have morning visibility about 9 days after launch. I did not make an
> exhaustive evaluation of visibility, so prospective observers should check
> local visibility.
> 
> Ted Molczan
> 
> 
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Received on Wed Nov 15 2017 - 03:31:07 UTC

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