Re: Satellite designations in orbit

Lynn + Steve Walter / LAST Acre (walterlc@huntel.com)
Thu, 22 Aug 1996 19:03:33 -0500

Regarding Philip Chien's...
>
>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.
>
>

... it IS proper to refer to TDRS-C as TDRS-3, since TDRS-2 still exists
(in a concrete graveyard down at the Cape, I believe).  I have been VERY
involved with each TDRS for about 10 years, now, and I've never heard of
TDRS-3 being referred to with the number '2'!

As a slightly further elaboration on TDRS, there've been 7 of them launched
to date, each essentially the same type of spacecraft (built by TRW).
[Tho, there are some key differences (improvements?) in each subsequent
craft.]

Philip is correct in that each TDRS carries a sequential-letter-designation
while on the ground.  And, I believe it is NASA's convention to change this
letter into the number corresponding to the alphabetic character once the
vehicle is on-orbit.  This practice does NOT stop folks from mixing
alphabet characters and their numbers, however -- it is, I'm afraid, such a
day-to-day mixture at the TDRS White Sands Complex.  My own, personal push,
is to steadily use the NASA convention of numbered craft once on-orbit.

FYI, by the way, the next 3 TDRS vehicles are being built by Hughes; they
currently contain the 'HIJ' designations (on the ground), and I suspect
will be referred to as TDRS-8,-9,-10 after launch.  These vehicles look
VERY different from the current series.

I hope this information is of use, or at least amusing!


Steve Walter







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