Satgen412   Hits and Misses  by GM4IHJ    (BID SGEN412)  15 Feb 97

Several readers have asked " How do we compare with commercial sats
with regard to launch and in orbit failures? ". So here is a brief
review . Taking the commercial sats first - In 1996 there were 77
launches of which 72 got into their designed orbit. There were 4 launch
failures - Intelsat 708; a Kosmos on May 14th ; the irreplaceable
Cluster Magnetospere probes in June and a second Russian Kosmos also in
June . All the rest got into designed orbits except for the ill fated
Russian Mars probe which reentered after less than 2 orbits. Amsat was
lucky with both Fuji29 and Unamsat Mo30 making it safely into orbit.

We were not so lucky in 1995 when the rocket carrying the first Unamsat
and the Israeli Techsat suffered a staging failure , lost power and
dumped our satellites back into the atmosphere over the Russian Far
East. Despite this loss however , we have not done too badly , with
launches prior to 1995 losing only one Amsat - Phase 3A, in 1980 and
even further back in 1965, Oscar IV failing to reach design orbit and
having in consequence a very short , albeit productive active life,
before early reentry.

Overall assessment is difficult because of the wide variation in
satellite failures over the years. But commercial /military launches
seem to have a roughly 3 to 4% failure rate. So Amsats 3 failures in 40
launches since 1961 suggests that we are not as fortunate by a factor
of 2. A feature which probably arises from our need to take any orbit
offered rather than wait for (expensive ) flights on proven launch
systems.

Looking at the post launch situation , there is not enough published
commercial information on in orbit failures to allow comparisons to be
made, although limited personal evidence at IHJ suggests that failure
in orbit is not uncommon. A situation which is repeated in the Amsat
records :-
  Two Uosats which were saved from death , only after Herculean efforts
involving the use of large radio telescopes to locate and wake them up.
  One Uosat which failed completely several days after launch.
  The French Arsene satellite which never became operational
  Plus various failures some time after launch , such as - the failure
of main transponder amplifiers for Mode L in Oscar 10 and, for Mode J
and L in Oscar 13. The less than satisfactory orbit of Oscar 10 which
led to its partial immobilisation due to loss of ground control; the
Phase keying problems of Pacsat, Lusat and Webersat,and the various
mode failures of the Dove satellite.
All things considered however our small problems have not prevented
thousands of radio amateurs , worldwide, enjoying satellite operations
of high quality. Unlike several commercial ventures which have perished
ignominiously and suddenly gone unreported , after an opening blast of
publicity, just as we are about to enter a period when commercial
builders say they will be orbiting up to 700 or more low earth orbit
sats. Things are already interesting, with one launch of this armada  
, first being delayed for a few days, but now going unreported, whilst,
a second group got two satellites into orbit 18 months ago, but have
yet to launch any of the other two dozen which we were told would be in
orbit some time ago.