NROL-67 search elements

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 9 Apr 2014 18:27:04 -0400
NROL-67 is scheduled for launch on an Atlas V-541, from CCAFS, on Thursday, April 10, 2014 at 17:45 UTC.

http://www.spaceflightnow.com/atlas/av045/status.html

I believe that it will launch a new generation of GEO SIGINT satellite.

The following rough search elements are derived from those used for NROL-15, based on launch at 17:45 UTC:

SECO 1                                                   190 X 244 km
1 79600U          14100.74846989  .00656932  00000-0  21234-3 0    02
2 79600  28.7000 287.5802 0040859  90.0000  38.0000 16.22456322    02

SECO 2                                                 212 X 35809 km
1 79600U          14100.75725697  .00000000  00000-0  00000-0 0    09
2 79600  26.5000 287.5116 7298000 180.0000   0.0000  2.28000000    04

SECO 3                                               35822 X 35906 km
1 79600U          14100.97594908  .00000000  00000-0  00000-0 0    02
2 79600   6.0000 287.4298 0010000 180.1373 179.8600  1.00000000    06

The payload is likely to drift west toward its initial operational location.

Some additional guesses:

I believe that this launch is the same one that was known for a time as AFSPC-2, which according to an unofficial
manifest on NASASpaceFlight.com, was to employ an Atlas V-541. The USAF budgeted about $27.5 million to qualify the
Atlas V extended mission kit (EMK) (aka GSO kit), which was to have first flown on AFSPC-2. The EMK enables the Centaur
stage to operate 6 h instead of the standard 2 h, required for 3-burn direct insertion GEO missions. There are two
common GEO launch profiles. In the first and most common, the launch vehicle's mission ends with insertion of the
payload near the perigee of a geosynchronous transfer orbit, and the payload completes the remaining manoeuvres to
reduce the inclination and circularize the orbit at GEO altitude, using a PKM, thrusters, or some combination. In the
other profile, the upper stage performs all of the major manoeuvres to reach the final GEO orbit, leaving only minor
adjustments for the payload.

With the exception of Rhyolite in the 1970s, NRO SIGINT satellites launched to Molniya or GEO, have relied on the upper
stage to perform all of the manoeuvres to reach their final orbit. The only non-SIGINT NRO satellite to use this mode,
was the SDS 1, during the 1970s and 80s.

The AFSPC-2 label later was assigned to AEHF-3, which employs the Atlas V-531 and does not require an EMK. About the
same time, NROL-67 appeared on public manifests, employing an Atlas V-541, which I strongly suspect is the former
AFSPC-2 vehicle and its EMK, which is strong evidence that it is the next generation GEO SIGINT.

The new spacecraft may share the same bus as the Trumpet-FO (Follow On) SIGINT, launched to Molniya from VAFB in 2006
and 2008: 2006-027A / 29249 on Delta IV-M (4,2), and 2008-010A / 32706 on Atlas V-411. Trumpet-FO satellites host the
SBIRS-HEO sensors. I have roughly estimated their combined mass between 3,900 and 4,500 kg.

U.S. GEO SIGINTs typically operate in orbits initially inclined between 5 and 7 deg. Based on the mission planner's
guide, the Atlas V 541 can directly insert about 3,850 kg into a 6 deg GEO orbit; the next smaller vehicle, 531, can
insert about 3,400 kg, so the payload range would be 3,400 kg to 3,850 kg, which seems about right for a Trumpet
Follow-On without the SBIRS sensor.

Fairing sizes disagree: Trumpet-FO employs 4 m fairings, NROL-67's is 5 m; however, the 3-burn insertion to GEO option
is only available for the Atlas V-521, 531, 541 and 551 (Atlas V User's Guide 2010, Sec. 2.3.1.5, 2.5.5., 2.6.3, Table
2.6-1, Fig. A.1-2), so the payload's dimensions may not have determined the fairing size.

Ted Molczan


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Received on Wed Apr 09 2014 - 17:27:49 UTC

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