Being the first space-rated orbiter produced, Space Shuttle Columbia was the heaviest and therefore rarely selected for high inclination trajectories like the ISS near the end of the program.

Which components were still heavier for Columbia compared to the other shuttles by 2003?

  • 2
    $\begingroup$ This does not answer your question but you might find it interesting space.stackexchange.com/q/40705/6944 $\endgroup$ Commented Feb 14, 2023 at 0:00
  • $\begingroup$ general structure around the tanks and cockpit maybe? also in-space propulsion... $\endgroup$ Commented Feb 14, 2023 at 1:07
  • 2
    $\begingroup$ @RegenerativelyCooledAstronaut "in-space propulsion"??? $\endgroup$ Commented Feb 14, 2023 at 1:37

1 Answer 1


The tl;dr answer is "structure, mainly in the wings".

I have struggled to find references giving details, though. I particularly wanted to find comparison diagrams, but I did not.

There are several references that give little parts of the story.

The differing weights of the orbiters reflected improvements in design that had accrued in the course of development. Though people spoke of “production” of shuttle orbiters, this was not at all like the massive aircraft orders of World War II. Every orbiter amounted to an individual procurement, and there was ample opportunity to change the blueprints from one to the next. Weight reduction was essential, for a lighter orbiter could carry correspondingly heavier payloads. It was achieved through use of titanium in the primary structure, as that metal was denser than aluminum but considerably stronger. Boron-epoxy composite, particularly light light in weight, also began to appear. This indicated a clear trend: early orbiters being heavy, even after refurbishment, and later ones being considerably less so:

  • Enterprise (as flight vehicle) 160,000 pounds
  • Columbia 158,000 pounds
  • STA-099 (as Challenger) 155,000 pounds
  • Discovery 151,000 pounds
  • Atlantis 151,000 pounds

Heppenheimer, Development of the Space Shuttle, 1972-1982, p. 348

Additionally, the wings were modified to incorporate lessons learned from the static testing just completed. Challenger would end up some 2,889 pounds lighter than the earlier Columbia.

Jenkins, Space Shuttle (1992 edition), page 166

After the initial design of Challenger and Columbia, NASA initiated a weight-savings program for the follow-on vehicles—Discovery, Atlantis, and Endeavour. The space agency achieved weight savings through optimization of aluminum structures and replaced the aluminum spar webs in the wing with a graphite/epoxy laminate.

Multiple authors, Wings in Orbit, Structural Design chapter, p. 275

I would love it if someone can come up with more details.

  • $\begingroup$ Does "Enterprise (as flight vehicle) 160,000 pounds" mean the estimated final weight had it been kitted out for spaceflight? I'd always assumed Enterprise was relatively lightweight due to the missing space hardware but I can't find any other references to its weight offhand. Maybe that's a separate question. $\endgroup$
    – CameronSS
    Commented Feb 16, 2023 at 21:49
  • 1
    $\begingroup$ @CameronSS Yes, I think it means that's what it would have weighed if they turned it into a spaceworthy Orbiter. Not 100% sure though. $\endgroup$ Commented Feb 16, 2023 at 22:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.