Some LEO search elements for 99028A.
Ted Molczan (molczan@home.com)
Sun, 30 May 1999 01:59:35 -0400
As I mentioned a couple of days ago, it is not a foregone conclusion that
the payload(s) of the 99028A launch were headed for a Molniya orbit. It is
conceivable that this was a NOSS launch, or perhaps some similar new
mission.
One fact that may point to a NOSS, is that its orbital plane would be about
the same distance from the plane of NOSS 2-3 as the separation between the
planes of the older NOSS 2-1 and 2-2 triads. That makes sense, since the
older satellites may be at or near the end of their useful lives, since they
are now 8 to 9 years old.
For those who might be interested in wild-goose chases, I have appended a
set of search elements for circular orbits of mean motion between 15.9 and
13.4 rev/d.
The search elements are NOT predictive - they merely define search planes
consistent with the circumstances of the launch. Since the position of the
putative satellite with these orbits is unknown, anyone wishing to search
must be prepared to stare at the orbital plane for an entire orbital period.
This is a time-consuming project, in terms of the set-up time and the
observation time, with an uncertain outcome. If the payload is on or near
one of these orbits, and bright enough to be seen, then skilful searchers
have an excellent chance of finding it. Otherwise, they will search in vain.
Since the Earth rotates under the plane of the orbit, allowance must be made
for the slow apparent movement of the plane across the sky. Some ephemeris
generators may have features that assist in allowing for the Earth's
rotation when an object's time of arrival is uncertain. If not, then it is
necessary to edit the elements directly, to vary either the epoch or mean
anomaly, in order to produce a series of ephemerides, at suitable time
intervals over one orbital period.
The concept is to plot a series of paths, at intervals of, say, 5 to 10
degrees of elevation. The time increment required to produce this spacing
varies. When the orbital plane is low above the horizon, it rises slowly.
When it is high above the horizon, it moves across the sky more rapidly.
Searches may be conducted with the unaided eye or binoculars, depending on
the circumstances. When the orbit is low above the horizon, the satellite is
likely to be faint, requiring the use of binoculars. Observing the plane
when it is low can be advantageous, because the uncertainties in the
inclination or RAAN have the least effect on the orbital path. That is
because the orbit is being viewed from the side. Slowly panning the
binoculars above and below the predicted path improves the probability of
spotting the object.
As the orbit rises, the satellite can be expect to be brighter, which may
permit using the unaided eye, provided that there is reason to believe the
object will be bright enough. Using the unaided eye provides a wider field
of view than binoculars, and is causes less fatigue.
Several participants on SeeSat-L have used the method described to detect
secret satellites, including the discovery of newly launches objects and
recovery of known objects. A good example of the latter, are the Keyholes,
which are cannot be observed in the N. hemisphere during winter, and so must
be recovered each spring.
In my successful search for the secret 89061B payload deployed from a
shuttle in Aug'89, I used binoculars at low elevations, and the unaided at
high elevations. The object was spotted using both methods on two different
nights. It had been deployed into a 57 deg orbit of mean motion about 15.9
rev/d, and subsequently manoeuvred up to a mean motion of 15.4 rev/d, which
is where I found it.
Searching may be something of wild goose chase; however, it is very
satisfying to discover a newly launched secret satellite.
Happy hunting!
Ted Molczan
The following search orbits assume that the object manoeuvred to the search
altitude shortly after separating from the Titan 2nd stage. The dimensions
and standard magnitude correspond to an object of the approximate dimensions
of payload fairing. If there are multiple payloads, then the standard
magnitude may be a couple of magnitudes too bright.
99142A 15.0 4.0 0.0 4.2 d
1 99142U 99142 A 99142.40367000 .00000000 00000-0 00000-0 0 08
2 99142 63.4100 103.2500 0010000 160.0000 343.4000 15.90000000 09
99142B 15.0 4.0 0.0 4.2 d
1 99143U 99142 B 99142.40367000 .00000000 00000-0 00000-0 0 09
2 99143 63.4100 103.2500 0010000 160.0000 343.4000 15.40000000 05
99142C 15.0 4.0 0.0 4.2 d
1 99144U 99142 C 99142.40367000 .00000000 00000-0 00000-0 0 00
2 99144 63.4100 103.2500 0010000 160.0000 343.4000 14.90000000 00
99142D 15.0 4.0 0.0 4.2 d
1 99145U 99142 D 99142.40367000 .00000000 00000-0 00000-0 0 01
2 99145 63.4100 103.2500 0010000 160.0000 343.4000 14.50000000 07
99142E 15.0 4.0 0.0 4.2 d
1 99146U 99142 E 99142.40367000 .00000000 00000-0 00000-0 0 02
2 99146 63.4100 103.2500 0010000 160.0000 343.4000 13.90000000 01
99142F 15.0 4.0 0.0 4.2 d
1 99147U 99142 F 99142.40367000 .00000000 00000-0 00000-0 0 03
2 99147 63.4100 103.2500 0010000 160.0000 343.4000 13.40000000 07