3 ms·

The Buran has a lot of innovation inside that exterior shell though. Its flight was fully autonomous, for example.

by riehwvfbk 2y ago

pinewurst 2y ago
Implemented on their on-board cluster of PDP-11skis. Really.
- riehwvfbk 2y ago
  There was also an entire programming language developed specifically for the Buran, and it was visual: https://en.m.wikipedia.org/wiki/DRAKON https://en.m.wikipedia.org/wiki/DRAKON
dredmorbius 2y ago
I've heard a few different accounts of both the US Space Shuttle and Soviet Buran's design decisions here. I've heard but cannot find a reference for the Space Shuttle being able to land autonomously except for the landing-gear release switch, which had to be manually toggled. This StackExchange thread has a similar observation (also without citation): <https://aviation.stackexchange.com/a/23992 https://aviation.stackexchange.com/a/23992> That may simply be an urban (or LEO) ledgend... (Up-thread there's discussion of issues with the US craft's somewhat uneven experience in attempting to automate other parts of the landing sequence.) There's a Nasa report on automated modes of the Shuttle as well, which notes that "converting the Shuttle fleet to an autonomous system will be challenging and expensive", here: <https://ntrs.nasa.gov/api/citations/20100033420/downloads/20100033420.pdf https://ntrs.nasa.gov/api/citations/20100033420/downloads/20...> (PDF) I also recall rationales offered for Buran's fully-automated operation being both that the Soviets had lower trust in their astronauts' ability and/or trustworthiness, and that fully-automating the craft enabled non-crewed test flights during project development. Again, no sources, and don't take me as any authority on this point.
- mrpippy 2y ago
  APU start/run, air data probe deploy, main-landing gear arm/down, drag chute arm/deploy, and fuel cell reactant valve closure were all landing steps that could only be performed manually. Post-Columbia, they developed a cable and software (RCO: Remote-Controlled Orbiter) to allow these to be triggered from ground controllers or flight software. https://ntrs.nasa.gov/api/citations/20070019347/downloads/20070019347.pdf https://ntrs.nasa.gov/api/citations/20070019347/downloads/20...
  - riehwvfbk 2y ago
    So how did the Buran complete its uncrewed flight? Or would that be post-Challenger (which is what I assume you meant by post-Columbia)?
    - mrpippy 2y ago
      No, the Shuttle post-Columbia. The use case was that in case an orbiter sustained irreparable tile damage on launch, the crew would hole up in the ISS for weeks until a rescue Shuttle could be launched. But it was still worth seeing if the damaged orbiter could re-enter and land, so they developed the cable (stored at the ISS) and software to allow an unmanned orbiter to allow that. Obviously was never used.
- avmich 2y ago
  On one hand, Buran creators explicitly looked into American design while working. On another, important parts in design are completely different. Saving expensive main engines? Not on the orbiter, but on separate rocket, in subsequent plans. Solid fuel boosters? Too risky, better use the world's most powerful liquid fuel engines. Carcinogenic onboard propellants for RCS? Use cryogenics instead, and make sure they're preserved well for a month of flight. A few improvements here and there, and while externally Buran is quite similar to Shuttle, the whole launching stack is already less so, and the list of different details is not that short.

The Buran has a lot of innovation inside that exterior shell though. Its flight was fully autonomous, for example.

pinewurst 2y ago

Implemented on their on-board cluster of PDP-11skis. Really.

riehwvfbk 2y ago
There was also an entire programming language developed specifically for the Buran, and it was visual: https://en.m.wikipedia.org/wiki/DRAKON https://en.m.wikipedia.org/wiki/DRAKON

dredmorbius 2y ago

I've heard a few different accounts of both the US Space Shuttle and Soviet Buran's design decisions here. I've heard but cannot find a reference for the Space Shuttle being able to land autonomously except for the landing-gear release switch, which had to be manually toggled. This StackExchange thread has a similar observation (also without citation): <https://aviation.stackexchange.com/a/23992 https://aviation.stackexchange.com/a/23992> That may simply be an urban (or LEO) ledgend... (Up-thread there's discussion of issues with the US craft's somewhat uneven experience in attempting to automate other parts of the landing sequence.) There's a Nasa report on automated modes of the Shuttle as well, which notes that "converting the Shuttle fleet to an autonomous system will be challenging and expensive", here: <https://ntrs.nasa.gov/api/citations/20100033420/downloads/20100033420.pdf https://ntrs.nasa.gov/api/citations/20100033420/downloads/20...> (PDF) I also recall rationales offered for Buran's fully-automated operation being both that the Soviets had lower trust in their astronauts' ability and/or trustworthiness, and that fully-automating the craft enabled non-crewed test flights during project development. Again, no sources, and don't take me as any authority on this point.

mrpippy 2y ago
APU start/run, air data probe deploy, main-landing gear arm/down, drag chute arm/deploy, and fuel cell reactant valve closure were all landing steps that could only be performed manually. Post-Columbia, they developed a cable and software (RCO: Remote-Controlled Orbiter) to allow these to be triggered from ground controllers or flight software. https://ntrs.nasa.gov/api/citations/20070019347/downloads/20070019347.pdf https://ntrs.nasa.gov/api/citations/20070019347/downloads/20...
- riehwvfbk 2y ago
  So how did the Buran complete its uncrewed flight? Or would that be post-Challenger (which is what I assume you meant by post-Columbia)?
  - mrpippy 2y ago
    No, the Shuttle post-Columbia. The use case was that in case an orbiter sustained irreparable tile damage on launch, the crew would hole up in the ISS for weeks until a rescue Shuttle could be launched. But it was still worth seeing if the damaged orbiter could re-enter and land, so they developed the cable (stored at the ISS) and software to allow an unmanned orbiter to allow that. Obviously was never used.
avmich 2y ago
On one hand, Buran creators explicitly looked into American design while working. On another, important parts in design are completely different. Saving expensive main engines? Not on the orbiter, but on separate rocket, in subsequent plans. Solid fuel boosters? Too risky, better use the world's most powerful liquid fuel engines. Carcinogenic onboard propellants for RCS? Use cryogenics instead, and make sure they're preserved well for a month of flight. A few improvements here and there, and while externally Buran is quite similar to Shuttle, the whole launching stack is already less so, and the list of different details is not that short.