Proposed Trumpet Satellite IDs

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 28 Oct 2014 08:48:42 -0400

We who have observed and/or analyzed the various unidentified satellites in Molniya orbits, have long suspected that
one or more first generation Trumpet satellites are found among them. I had tentatively identified Trumpets 2 and 3
more than five years ago, but procrastinated on finalizing the work. I have recently updated my analysis, confirming
my earlier findings and adding a third one, resulting in the following proposed identifications:

Trumpet 1 94026A / 23097 = 13772A / 99069
Trumpet 2 95034A / 23609 = 05864A / 90046
Trumpet 3 97068A / 25034 = 08628A / 90081

They are based on analysis of orbits and optical characteristics.

1. Trumpet 1 orbit correlation

Trumpet 1 was discovered as an unidentified satellite by Robert McNaught in March 1999, and was observed by our
group until August 2001. Its last known elements were:

                                                      1019 X 39327 km
1 23097U 94026A   01218.86193933  .00000000  00000-0  00000-0 0    09
2 23097  63.6810  37.3604 7213998 272.7734  14.3730  2.00658116    08

Cees Bassa discovered 13772A / 99069 in September 2013. Below is one of Mike McCants' TLEs not long after discovery.

1 99069U 13772A   13303.66215491  .00000120  00000-0  00000-0 0    03
2 99069  64.0341 255.5737 6625708 275.9944  17.7142  2.00614283    09

Propagating back to the epoch of last known 94026A orbit using int2 yields a reasonably close match in RAAN and
argument of perigee:

1 70000U          01218.88349248  .00000000  00000-0  00000-0 0    08
2 70000  62.7138  51.5523 7183858 265.7745  16.9475  2.00614283    01

2. Trumpet 2 orbit correlation

Trumpet 2 was never knowingly tracked by our group. Based on what is known from the launch of Trumpet 3, this was
its approximate initial orbit:

                                                      1100 X 39058 km
1 72003U          95191.61888889  .00000000  00000-0  00000-0 0    06
2 72003  63.5530  20.4880 7173330 271.4220  34.6950  2.01725877    06

05864A / 90046 was first observed in Dec 2005, by Greg Roberts. Below is one of Mike McCants' TLEs, not long after
the initial observation.

1 90046U 05864A   06010.57228911  .00000000  00000-0  91732-1 0    01
2 90046  63.4777 260.3201 6955666 276.1068  83.8932  2.00613355    00

Propagating back to the epoch of the initial orbit of 95034A using int2 yields a reasonably close match in RAAN and
argument of perigee:

1 70000U          95191.74314390  .00000000  00000-0  00000-0 0    06
2 70000  63.1272  41.9975 7190827 265.2141  17.0987  2.00613355    07

In Dec 1995, Chinese astronomers observed what probably was Trumpet 2. It was among several observations of
geocentric UNIDs reported to the Minor Planet Center, relayed to SeeSat-L by Jonathan McDowell:

http://satobs.org/seesat/Jun-1996/0036.html

Mike McCants identified all except an intrinsically bright object for which the observations supported a large
number of possible Molniya orbit solutions:

http://satobs.org/seesat/Jun-1996/0047.html

B01600  CC1995 12 29.60910 07 35 22.10 +65 53 43.0           9.9 V      327
B01600  CC1995 12 29.61076 07 37 50.94 +65 50 59.7           9.7 V      327
B01600  CC1995 12 29.63807 08 17 55.96 +64 40 02.9           9.4 V      327
B01600  CC1995 12 29.63830 08 18 17.64 +64 39 01.4                      327
B01600  CC1995 12 29.63866 08 18 45.90 +64 37 58.7           8.9 V      327
B01600  CC1995 12 29.63935 08 19 47.51 +64 35 18.3                      327

Observation site: Alt 870 m, long 117 deg 34 30, lat +40 23 39.3

This was Mike's solution, assuming an operational spacecraft:

1 99999U          95363.47096110 0.00000000  00000-0  00000+0 0    01
2 99999  63.6860   6.3781 7160000 272.0170  87.9830  2.00600000    03

The above 05864A TLE, when propagated to the same date, is in good agreement:

1 70000U          95363.71482844  .00000000  00000-0  00000-0 0    04
2 70000  63.1015  17.9310 7231383 266.0484  16.4385  2.00613355    05

The Chinese observations could also have been of the Centaur of Trumpet 2, which would still have been close in RAAN
to its payload. Trumpet 1 and its Centaur were in orbit, but far away in RAAN. Whether payload or Centaur, it seems
likely that the Chinese observations were related to Trumpet 2, assuming 05684A is that object.

3. Trumpet 3 orbit correlation

Trumpet 3 was first observed by Mike McCants, on the night of its launch in Nov 1997. It was discovered as an
unidentified satellite by Robert McNaught in May 1999, and tracked by our group until Feb 2003. Its last known
elements were:

1 25034U 97068A   03038.62633649 -.00000400  00000-0 -28754 0 0    01
2 25034  63.1890 111.1910 6997000 268.0405  91.9595  2.00593611    08

08628A / 90081 was first observed in May 2008, by Peter Wakelin. Below is one of my TLEs from not long after the
initial observation.

1 90081U 08628A   08128.60175929  .00000000  00000-0  00000-0 0    03
2 90081  62.8204 215.2087 6814408 276.8656  16.0137  2.00587822    00

Propagating back to the epoch of last known 97068A orbit using int2 yields a close match in RAAN and argument of
perigee:

1 70000U          03038.73399731  .00000000  00000-0  00000-0 0    06
2 70000  62.8083 112.6499 7011678 264.2909  19.0600  2.00587822    00

4. Additional comments on orbits

All three objects clearly are payloads, as evidenced by their periodic manoeuvres to maintain semi-synchronous mean
motion.

All tend to maintain longitude of ascending node values that can be associated with U.S. Molniya SIGINT satellites.
I do not intend to go into details, but it could be a worthwhile line of research for someone so inclined. For the
present discussion the significance is that longitude of ascending node helps to distinguish between Trumpet and SDS
satellites.

5. Standard visual magnitude comparison

The following file presents plots of magnitude normalized to 1000 km vs. phase angle of the known and suspected
Trumpets.

http://satobs.org/seesat_ref/misc/Trumpet_brightness_plots.pdf

I believe it is fairly self-explanatory. They were generated using the following spreadsheet, which includes many
more plots involving the same objects.

http://satobs.org/seesat_ref/misc/Trumpet.xlsx

There are plenty of observations of 05864A and 08628A to decide with confidence that they likely are first
generation Trumpets, consistent with the orbit analysis.

We have only 11 brightness observations of 13772A. They fall nicely within the envelope of the known Trumpets and
the other suspects. Although this data is rather thin, I believe it is sufficient to support the proposed ID, when
combined with the orbital analysis.

For a time, I suspected that 08731A / 90082 was Trumpet 1, because the initial brightness data seemed like a
possible fit. Peter Wakelin helped resolve that question by producing numerous additional brightness measurements
from his archived imagery, that revealed the true relationship with phase angle, which proved that it is too faint
to be a Trumpet.

An important caveat with all of the brightness data: it was generated using a variety of different equipment and
methods, some of which have changed considerably over time. We have no practical method to account for the
differences between methods, but they undoubtedly at least somewhat impair comparability of observations, especially
over the years.

6. Discussion

The modern SDS and both Trumpet Follow-On s/c are all accounted for. No Jumpseat or any generation of SDS would be
expected to be as bright as the three objects in question; therefore, the correlations are well constrained to first
generation Trumpet.

After we lost track of Trumpets 1 and 3, more than a decade ago, I naively suspected they had been de-orbited or
allowed to be forced out of orbit by luni-solar perturbations. Since then, tracking by ourselves, but especially by
ISON, has enabled accounting for all of the U.S. SIGINT spacecraft in GEO, from which it became apparent that
multi-decade service life is common. Luni-solar perturbations can be especially severe for HEO orbits, but with
careful design of orbits and sufficient propellant, a service life of two decades is not surprising.

Ted Molczan



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