Satellite designations in orbit - was re: Perseid/Stellafane/NOSS FAQ

Philip Chien (
Thu, 22 Aug 1996 02:43:36 -0400

 dk058@cleveland.Freenet.Edu (Walter Nissen) asked:

>Has anyone paid attention to whether there might be any preference for one
>or the other?  I recall pointing out that EGP's name changed to EGS.  But
>no one I know seems to care.  Does anyone have statistics about which type
>of name predominates?

Actually name changes happen more often than not.  As a rule tracking
people tend to use the names which are given to satellites after they reach
orbit, and manufacturers tend to their original contract designations.
Many payloads have one designation on the ground, and then another one in
orbit, depending on who you're talking to.

When Hughes contracted to build two HS-601 satellites for Australia, they
were originally known as the Aussat B series.  Later the customer chose to
rename them Optus, well before their launches.

Each of the Japanese satellites is given a rather poetic name after it
becomes operational in orbit.  EGP/EGS is Ajisai for example.

Ham satellites usually have a project designation on the ground, and an
OSCAR designation once they're in orbit.  For example, Japan Amateur
Satellite-2 (JAS-2) was the piggyback payload on the recent H-II launch,
and should be named Fuji OSCAR-29 in the near future.  (Fuji for Japan,
OSCAR = Orbital Satellite Carrying Amateur Radio, 29 for the 29th amateur
satellite to be placed in orbit).  If an amateur satellite does not achieve
orbit (e.g. Phase 3-A lost in an Ariane 1 accident or UNAMSAT-A lost in a
START accident) then it isn't given a OSCAR designation.  However once an
OSCAR designation is given it doesn't go away, even if the satellite has an
activation failure.  I'm currently helping build the Phase 3-D satellite,
which will _PROBABLY_ become AO-31 when it reaches orbit.  The actual
number depends on the schedules of other amateur satellites scheduled for
launch over the next year or so, which launch vehicles get delayed, which
launch vehicles are failures, etc.  So I don't know what my satellite will
be called until shortly before launch!

NASA uses designations for its payloads based on its contracts with its
customers, but the customer may call their satellites by different
designations once they're in orbit.  The Telesat series went up through
about H or I if I recall correctly, but those satellites were known as the
Anik D series or Anik C series, etc.

Telstar 3A, 3B, and 3C, were renamed Telstar 301, 302, and 303 in orbit.

The Telstar 403 ground spare satellite became Telstar 402R because of the
failure of Telstar 402 shortly after launch.

Galaxy 1 was supposed to be replaced by Galaxy 1R, but Galaxy 1R was lost
in an Atlas launch vehicle failure.  The replacement replacement was
launched on a Delta, but just to confuse the issue was also known as Galaxy
1R.  So there are two spacecraft which have that designation, but only one
which made it to orbit.

The GOES weather satellites use letters on the ground (GOES I,J,K for the
current series, and get numerical designations in orbit (GOES 8 and 9 in
orbit now, GOES K becomes GOES 10 after it is activated in orbit).  The
reason the numbers don't match the letters is the launch failure of GOES-G,
which would have been GOES 7.  Since it failed to rach orbit GOES-H became

The UHF series of satellites is actually two separate purchases, three
UHF-only satellites, and seven with the additional EHF capabilities.  These
satellites have also been known as UFO (UHF Follow On) and SHF.  And once
Hughes turns them over to the Navy they get USA designations too.

Pioneer Venus Orbiter and Pioneer Venus Probe are a/k/a Pioneer 11 and 12.

Navstar satellites receive GPS designations, etc. etc.

A shuttle mission has many different designations including STS-79,
Atlantis, OV-104-17, Mir 4, etc.

The key confusion is the TDRS series.  TDRS-A became TDRS-1 in orbit.  Fine.
TDRS-B was lost in the Challenger accident.  TDRS-C was launched on STS-26,
and presumably should have been renamed TDRS-2, however it wasn't - it was
named TDRS-3.  So the designation TDRS-2 was never used, a contradiction of
how all other NASA satellite series have been named.

Philip Chien, Earth News - space writer and consultant  PCHIEN@IDS.NET
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