Zuma pre-launch elements

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Thu, 16 Nov 2017 02:02:47 -0500
Zuma is scheduled for launch from Cape Canaveral on a Falcon 9 v1.2 on 2017
Nov 17, during a 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:


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.

Marco Langbroek has posted 50 deg inclination TLEs for altitudes of 300 km,
400 km and 500 km, at 30 min. intervals during the launch period:


Closer analysis of the stage 2 de-orbit NOTAM, reveals that at de-orbit the
inclination is closer to 52 deg, and the RAAN is about 8 deg west of that of
the 50 deg orbit derived from USA 276. This does not invalidate the Zuma 50
deg orbit hypothesis. It would be well within the performance of stage 2 to
increase its inclination by 2 deg and decrease RAAN by 8 deg for de-orbit,
which represents a 6.5 deg plane change. The manoeuvre could be performed
near 48 deg N descending or 48 deg S ascending, and would require delta-V of
0.114 times orbital velocity. However, different mission profiles are

One possibility would be for Zuma to be deployed into a 52 deg inclination
orbit of 1000 km altitude, with RAAN about 2.4 degrees east of the 50 deg
orbit derived from USA 276. The higher orbit would delay the de-orbit of
stage 2 sufficiently to allow the de-orbit zone to rotate directly under the

The mission could be begin with a 300 km parking orbit:

Parking orbit                                            292 X 313 km
1 70000U 17999A   17321.04166671  .00011340  00000-0  15763-3 0    04
2 70000  52.0000 327.1356 0015627 353.6173  19.7000 15.90000000    04

Following an apogee raising manoeuvre at 01:20 UTC, and a circularization
burn at 02:09:20 UTC, Zuma would be deployed into the following orbit: 

Zuma                                                     998 X 999 km
1 70000U 17999A   17321.08981482  .00011340  00000-0  15763-3 0    03
2 70000  52.0000 326.9128 0001000  95.1090 179.9200 13.70400000    05

Stage 2 de-orbit at 03:00:20 UTC would result in the following orbit, which
would re-enter at about 03:40 UTC, on a track that follows close to the
centre-line of the de-orbit NOTAM.

Stage 2 de-orbit                                          14 X 999 km
1 70000U 17999A   17321.12523149  .00000000  00000-0  00000-0 0    06
2 70000  52.0000 326.7822 0715000 270.0000 179.8000 15.20000000    01

The above is only one of many possible solutions. The inclination and RAAN
of the parking orbit determine the altitude of the final orbit of Zuma that
would we required for the second stage to align with the de-orbit NOTAM
zone, which could be well over 1000 km. Some scenario's would also require
stage 2 to make a small plane change.

I have no idea what will happen. It would be prudent to begin searches using
the 50 deg orbits that Marco posted, but be prepared to consider orbits a
bit higher in inclination, and quite a bit higher in altitude.

Ted Molczan

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Received on Thu Nov 16 2017 - 01:03:25 UTC

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