Zuma pre-launch elements

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 14 Nov 2017 16:59:20 -0500
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 Tue Nov 14 2017 - 16:00:16 UTC

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