Space Forum / Shuttle / November 2005

No...STS-1,2,3,4,5,6,7,8,9 went in order.  Then the numbering system
went like this:
first number was the fiscal year the flight was planned (4=
1984,5=1985,6=1986)  The second number referred to the launch site.
1=Kennedy Space Center, 2would have equaled Vandenberg AFB in
California, which they planned to use for polar-orbital flights
(flights going over the poles) but those plans were scrapped after the
Challenger accident)  The letter obviously refers to the order in which
they were to be flown. So after STS-9 (which would've been STS-41A
under that system, because even though flown in 1983, NASA's fiscal
year begins on October 1st), came STS-41B, then 41C, then 41D...then
E/R were cancelled and/or consolidated into 41D and so next was
41G...and then came the "5" series, STS-51A, then 51C, 51D (which
combined Dand E) then 51B, and then I'm a little shaky on the order but
I think it was 51G, 51F, 51I, 51J...then STS-61A, B, and C...then
STS-51L ("challenger") which even though flown on 1/28/86..was planned
for flight earlier obviously.  After the accident, when they returned,
they went back to more "normal" numbering, starting w/STS-26.
John

No.

STS-41A was orginally designated STS-9 and is generally remembered as
such. The next flight was to be STS-10, but this mission was cancelled
(I believe it was the abandoned military "Teal Ruby" mission, but I
might be wrong.)

The subsequent STS-11 was designated STS-41B when it flew in February
1984.

In 1983, NASA inexplicably decided it needed a new Shuttle Mission
designation scheme for the general public. It still followed the old
STS-n formula internally even while STS-41B, 41C, etc. were the
"official" designations. NASA's desire to avoid so obviously flying
missions out of order (proving delays and other problems) is probably
the primary reason for the change. They may also have been trying to
avoid flying an "STS-13". Who knows...

The Challenger disaster on the 25th Shuttle flight was designated
STS-33 internally and STS-51L for the general public.

The "41A' scheme indicated...

4 = Program Year (not calendar year) of Shuttle program flights (1981
was 1, 1982 was 2. 1990 would have been "10" not "0".)

1 = Launch Site (1 = KSC, 2 = Vandenberg AFB)

A = Flight as assigned sequentially in the program year. A=1, B=2,
etc.

After Challenger, NASA eventually returned to the simpler STS-n
scheme. They let the missions fly when they were ready, regardless of
their number on the original manifest. Hence, Columbia was lost on
STS-107, the 113th Shuttle flight.

Brian