Anyone want to try this?

Greg Roberts (
Tue, 19 Nov 1996 11:11:49 +0200

Visual satellite observers might be interested in trying to recover the
satellite 1971-110C for which no elements have been available for about
a decade. Fortunately during all this time the satellite has been
transmitting on 137.080 MHz and I have been tracking it somewhat
irregularly by radio over this period. Earlier I posted a set of crude
elements,derived from radio observations, to the HEARSAT mailing list
and yesterday I mailed a second set of improved elements again to HEARSAT.
Walter Nissen feels I should make this data available to SEESAT members
in case anyone wants to have a look for it.

I am in two minds about this as I feel the radio data is not yet good
enough for visual observers to waste their time, but maybe there are one
or two people who have nothing "better" to do. The satellite is rather
small physically and around about 8th magnitude. The satellite itself is
a precursor to the SSU series of satellites. I cannot recall offhand if
it has a companion or two.During the early 70's, when I tracked it by
radio,there were two transmissions received at the same time from two
different satellites travelling as a pair and it took me quite a while to
decide which frequency belonged to which satellite. Although it was 
definately a 71-110 launch pair I cant recall, without digging through old
record books, whether it was 71-110C and a companion or not.

As to the accuracy of the elements:

The inclination is probably good to within a tenth of a degree. The epoch
time is a predicted equator crossing time based on a 30 degrees South
latitude crossing observed by radio.The error here should not be more than
a few seconds. The orbital period is the main uncertainty - the period
given was derived from a weeks observation of radio passes and the period
was adjusted to give a reasonable fit.I am reasonably confident that the
figure given is pretty close but I am sure it can be refined still more.
Like all element sets the error will get bigger the further one goes from
the epoch-I will issue new elements again once I have enough passes to
justify changing the period. The R.A. of node has the biggest uncertainty
and at the moment I think its good to within a degree or two. The drag term
will be very low and at this stage,with the uncertainty in period,is
meaningless. The orbit is essentially circular so the eccentricity is very
small.With a near circular orbit the argument of perigee is difficult to
define and since mean anomaly is related to the argument of perigee this is
also difficult to define.

So thats the story. I have morning visibility shortly and, if I can motivate
myself enough, will attempt to try some passes optically.Meanwhile if anyone
else wants to try optically I would be interested in your observations.


1 05680U 71110C   96322.73794648  .00000001  00000-0  00000-0 0    25
2 05680  70.0000 325.9018 0000001 327.8540  32.1460 13.73846979    10