Author Topic: STS flight numbering system  (Read 13268 times)

Offline AstroRJY

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STS flight numbering system
« on: 07/23/2007 02:00 am »
A couple of questions for those who actually know:

What was the logic in shifting from numbering flights STS-8, STS-9, etc. to  the STS-41B, STS-41C system, etc.  I know the 4 was fiscal year 84 the 1 was for KSC (because before Challneger they planned to have a 2 meaning Vandenberg, CA) and then the letter was supposed to alphabetically correspond with the flight of that year, meaning B is the second scheduled flight of 1984 from KSC,  C is the 3rd flight for 1984, etc.  Obviously during the interim between 1986-1988 they decided to go back to the STS-26 numbering.  I remember at the time asking a JSC PAO person why and she said " it was too hard for the public to figure out."

I still wonder why the Challenger launch planned for January 1986, following 61-A, B, and C, still was numbered as 51-L, which literally means the 12th planned flight of fiscal year 1985.

Since STS-26 in 1988, only 23 flights in 19 years have launched in the order to which missions were assigned:

STS-26, STS-27, STS-44, STS-55, STS-58, STS-60, STS-64, STS-66, STS-70, a long string from STS-75 though STS-84, STS-89, 90 and 91, and then STS-114.
(Source: Bill Harwood's STS Chronology on CBS News space website.)

All the others slipped ahead or behind by 1 or 2 here and there.

Also does anyone have the list of all the ORIGINAL STS flight assignments from 1984 and 1985?  For example 41-B was originally STS-11, 41-C was STS-13, 41-D was STS-12, etc.  I read it years ago in a book, possibly one of the Tim Furniss sapce shuttle books.


Offline Thorny

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Re: STS flight numbering system
« Reply #1 on: 07/23/2007 02:17 am »
There have been various reports explaining the redesignation of Shuttle missions beginning in 1983/84, NASA wanted to avoid another "13". NASA wanted to make it less obvious to John Q. Public how far behind schedule Shuttle was, NASA didn't want people wondering what happened to the cancelled STS-10, etc. Note that NASA never really abandoned the original scheme. Internally, the Challenger disaster was referred to as STS-33. The STS-33 which flew in 1989 was then internally called STS-33R.

The first number in "41-B" was actually the "program year" (Fourth fiscal year of Shuttle flights) not 1984. 1990 (Program Year 10) would have seen 10-1-B not 01-B, had the scheme continued.

Once a mission was assigned a designation, it kept it, despite delays. Hence 51-L (slipped into 1986 by continuing IUS redesign difficulties, and with 51J getting IUS priority) kept 51-L rather than be redesignated 61D, and bumping the mission that already had 61D. That also explains why so few missions flew in their correct numerical order later... as flights were delays, high priority missions moved up to stay closer to their schedule, sometimes out of necessity (the Magellan, Galileo and Ulysses launch windows, for instance.)






Offline Jim

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Re: STS flight numbering system
« Reply #2 on: 07/23/2007 02:20 am »
One of the stories was to avoid STS-13.  Another was they wanted to track missions/payloads vs flights.  
"I still wonder why the Challenger launch planned for January 1986, following 61-A, B, and C, still was numbered as 51-L, which literally means the 12th planned flight of fiscal year 1985"

Like you said, it was "planned:.  TDRSS  problems delayed the mission

Offline AstroRJY

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Re: STS flight numbering system
« Reply #3 on: 07/23/2007 02:27 am »
"The first number in "41-B" was actually the "program year" (Fourth fiscal year of Shuttle flights) not 1984. 1990 (Program Year 10) would have seen 10-1-B not 01-B, had the scheme continued."

I read repeatedly that the first number indicated fiscal year, which for the federal government. runs Oct. 1- Sept. 30 of the following calendar year, hence all the flights like 51-A startting in Nov. 1984, 61-A starting in Oct. 1985..

Anyways thanks very much, this is good, useful info.

Offline AstroRJY

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Re: STS flight numbering system
« Reply #4 on: 07/23/2007 02:29 am »
Quote
Jim - 22/7/2007  10:20 PM

One of the stories was to avoid STS-13.  Another was they wanted to track missions/payloads vs flights.  
"I still wonder why the Challenger launch planned for January 1986, following 61-A, B, and C, still was numbered as 51-L, which literally means the 12th planned flight of fiscal year 1985"

Like you said, it was "planned:.  TDRSS  problems delayed the mission


They actually thought they could launch 12 flights in one year?  Well they did get 9 off  during all of 1985 which I think is still a record pace.... just checked yeah, managed 8 launches in 1992 and 1997.

Offline Thorny

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Re: STS flight numbering system
« Reply #5 on: 07/23/2007 02:34 am »
Quote
AstroRJY - 22/7/2007  9:29 PM

They actually thought they could launch 12 flights in one year?  Well they did get 9 off  during all of 1985 which I think is still a record pace.... just checked yeah, managed 8 launches in 1992 and 1997.

They came 14 seconds from launching a tenth flight in 1985. 61-C was scrubbed on December 19 by an SRB problem, and they did launch ten in one 365 day period, from January 24, 1985 to January 12, 1986, with the doomed 51-L launching on January 28, 1986.


Offline Jim

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Re: STS flight numbering system
« Reply #6 on: 07/23/2007 03:23 am »
Quote
Thorny - 22/7/2007  10:17 PM
 1. Note that NASA never really abandoned the original scheme. Internally, the Challenger disaster was referred to as STS-33. The STS-33 which flew in 1989 was then internally called STS-33R.

2.The first number in "41-B" was actually the "program year" (Fourth fiscal year of Shuttle flights) not 1984. 1990 (Program Year 10) would have seen 10-1-B not 01-B, had the scheme continued.

3. Once a mission was assigned a designation, it kept it, despite delays. Hence 51-L (slipped into 1986 by continuing IUS redesign difficulties, and with 51J getting IUS priority)


1.  It was KSC that kept the orginal scheme because of their paperwork.  JSC and the SSP fully accepted the new system

2.  It was fiscal year not "program" year

3.  It was TDRSS problems

Offline AstroRJY

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Re: STS flight numbering system
« Reply #7 on: 07/23/2007 03:38 am »
I think by IUS problems and TDRS problems (one S) he was referring to the IUS booster used to launch large spacecraft like TDRS satellites and other planetary craft once they were clear of the oriter in space.

Offline Jorge

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Re: STS flight numbering system
« Reply #8 on: 07/23/2007 05:45 am »
Quote
Jim - 22/7/2007  10:23 PM

Quote
Thorny - 22/7/2007  10:17 PM
 
2.The first number in "41-B" was actually the "program year" (Fourth fiscal year of Shuttle flights) not 1984. 1990 (Program Year 10) would have seen 10-1-B not 01-B, had the scheme continued.

2.  It was fiscal year not "program" year

I think I'm to blame for that unfortunate term. I was trying to come up with a shorthand for "fiscal year minus 1980" since the usual definition of "last digit of fiscal year" doesn't explain what happens in fiscal year 1990. There wouldn't have been an extra dash, so the first flight in FY90 would have been 101-A.
JRF

Offline SpaceNutz SA

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Re: STS flight numbering system
« Reply #9 on: 07/23/2007 06:45 am »
Hard to believe that in the age of technology - and with NASA leading the way - that they are still superstitious about the number 13  :)
"Lets not make things worse by guessing" - Gene Kranz - Apollo 13 Flight Director

Offline Celeritas

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Re: STS flight numbering system
« Reply #10 on: 07/23/2007 11:35 am »
Quote
SpaceNutz SA - 23/7/2007  2:45 AM

Hard to believe that in the age of technology - and with NASA leading the way - that they are still superstitious about the number 13  :)

I know.  Especially since it's bad luck to be superstitious.  ;)

Offline Thorny

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Re: STS flight numbering system
« Reply #11 on: 07/23/2007 02:27 pm »
Quote
Jim - 22/7/2007  10:23 PM

2.  It was fiscal year not "program" year

No, it was year of Shuttle operations, sometimes called "program year". It happens to coincide that 1984 was the fourth fiscal year of Shuttle flights, but the problem with the simple "fiscal year" explanation is, "What happens in 1994? Do you have another 41-B"? No, the second flight in 1994 would have been 141-B.



Offline Jim

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Re: STS flight numbering system
« Reply #12 on: 07/23/2007 03:39 pm »
NO, it was fiscal year.

I was in the USAF shuttle program office working manifests.  

Program year had no meaning wrt anything.

they hadn't even thought about repeating numbers at the time.

Explain how
61-A flew in 1985
51-A flew in 1984

NASA still  does it manifesting based of fiscal years

http://enterfiringroom.ksc.nasa.gov/funFactsSTSNumbers.htm

Offline brihath

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Re: STS flight numbering system
« Reply #13 on: 07/23/2007 05:06 pm »
I agree with Jim-

There was an Aviation Week article at the time that said the same thing- flights were ordered by U. S. Government Fiscal year: 10/1 to 9/30, based upon initial planned launch dates.  That is why 41G flew in October 1984 (FY1985), but was originally scheduled to fly before the FY rolled over.  I think the next flight after that was 51A- November 1984.

Offline Thorny

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Re: STS flight numbering system
« Reply #14 on: 07/23/2007 05:24 pm »
It was Fiscal Year, I agree. But the "year" was not 1984, but Year 4. That's why the designation wasn't 841-B but 41-B.


Offline Jim

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Re: STS flight numbering system
« Reply #15 on: 07/23/2007 06:03 pm »
Quote
Thorny - 23/7/2007  1:24 PM

It was Fiscal Year, I agree. But the "year" was not 1984, but Year 4. That's why the designation wasn't 841-B but 41-B.


No such thing as Year 4.  It was just the last digit of the fiscal year, period.    

Like I said, the 90's were not accounted for and so 101-A was not the nomenclature.

Offline GLS

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Re: STS flight numbering system
« Reply #16 on: 07/23/2007 06:24 pm »
AstroRJY, the list of goes like this:
STS 9 -> (STS 41-A)
STS 10 -> (DOD, cancelled)
STS 11 -> STS 41-B
STS 12 -> (OV-103, TDRS-C then TDRS-B, cancelled, crew moved to STS 14)
STS 13 -> STS 41-C
STS 14 -> STS 41-D (original, *cancelled*)
STS 14R -> STS 41-D (41-D + 41-F, after the RSLS abort)
STS 15 -> STS 41-E (OV-099, DOD, cancelled)
STS 16 -> STS 41-F (OV-103, cancelled)
STS 17 -> STS 41-G (this was going to be on OV-102, after the mods, but they got delayed so it moved to OV-099)
STS 18 -> STS 41-H (cancelled, crew moved to STS 51-A)
STS 19 -> STS 51-A
STS 20 -> STS 51-C
STS 21 -> STS 51-B (switch with STS 51-C, and then delayed to STS 24)
STS 22 -> STS 51-E (cancelled, crew moved to STS 51-D)
STS 23 -> STS 51-D (original crew moved to STS 51-G)
STS 24 -> STS 51-B
STS 25 -> STS 51-G (original crew moved to STS 61-A or STS 61-B (can't remember it right now))
STS 26 -> STS 51-F (moved from STS 24)
STS 27 -> STS 51-I
STS 28 -> STS 51-J
STS 29 -> (STS 51-H or STS 51-K, cancelled)
STS 30 -> STS 61-A
STS 31 -> STS 61-B
STS 32 -> STS 61-C
STS 33 -> STS 51-L (moved from STS 26)
STS 34 -> STS 61-E
STS 35 -> STS 61-F
STS 36 -> STS 61-G
....

both STS 61-F and STS 61-G (Galileo and Ulysses), never moved from STS 35, STS 36 since at least mid 1984, these 2 where written in stone (planets won't wait for you...) and the missions, crews and OVs moved around thying to keep these 2 in May 1986.
There where a LOT of changes in this period... there's still a lot of stuff I don't know, so there might be some data missing...
They went back to the regular numbering in October 1986.
GLS is go for main engine start!

Offline Thorny

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Re: STS flight numbering system
« Reply #17 on: 07/23/2007 07:06 pm »
Quote
GLS - 23/7/2007  1:24 PM
STS 30 -> STS 61-A
STS 31 -> STS 61-B
STS 32 -> STS 61-C
STS 33 -> STS 51-L (moved from STS 26)
STS 34 -> STS 61-E

Whatever became of 61-D?

Offline Thorny

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Re: STS flight numbering system
« Reply #18 on: 07/23/2007 07:08 pm »
Quote
Jim - 23/7/2007  1:03 PM

Like I said, the 90's were not accounted for and so 101-A was not the nomenclature.

At the time of Challenger, they didn't have a rough schedule that went out into FY1990?

Offline Michael Cassutt

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Re: STS flight numbering system
« Reply #19 on: 07/23/2007 07:15 pm »
Quote
Thorny - 23/7/2007  2:08 PM

Quote
Jim - 23/7/2007  1:03 PM

Like I said, the 90's were not accounted for and so 101-A was not the nomenclature.

At the time of Challenger, they didn't have a rough schedule that went out into FY1990?

NASA had a whole list of customer requirements and payloads, but the last formal manifest -- pre-Challenger -- that I possess is dated November 1985 and only projects through "81-N" in September 1988.

Michael Cassutt

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