YouTube auto-played this to me after Scott Manley. I don't really recommend this channel as there are a lot of small errors due to the speaker's unfamiliarity with the science and mis-speaks like altitude where it should be attitude or lifting a paragraph of an Astronaut's published article in Space.com without crediting the print source or providing a link.

The context is that the ISS needs astronauts on-board to help solve problems like these. But would recovery from these three problems have each required astronauts on board?

All of these problems were mitigated because of the collaborations between engineers on the ground and in the station.

enter image description here

From YouTube here

  • 1
    $\begingroup$ I think a potentially more interesting question is whether mitigation of such problems could have waited until the next time astronauts arrived at the station. $\endgroup$ – kasperd Oct 22 '18 at 10:18
  • $\begingroup$ @kasperd That's a very good question; each case is different. Consider choosing one and asking a new question! The scenario described by retired Astronaut and Expedition 10 cmdr. Leroy Chiao as linked here would be horrendous to try to recover from, and the loss of attitude control might make reentry happen even faster. But for a slow leak (say days or weeks) the answer might be much more interesting. $\endgroup$ – uhoh Oct 22 '18 at 10:22

The near collision

According to the NYTimes

In the section of the station run by the United States, astronauts closed the hatches in case the debris — commonly known as space junk — crashed through, to limit the danger of explosive decompression

So action done by the astronauts would have helped mitigate an actual collisions.

Answer: kind of.

The air leak in 2004

According to Space Safety Magazine

With just two crew members on board NASA’s Michael Foale and Roscosmos’ Alexander Kaleri – it took three weeks to locate the leak using a handheld ultrasonic probe.

And this video of astronauts fixing a leak. Youtube

This is an actual video of the astronauts fixing the leak.

Answer: YES!

  • $\begingroup$ Will try to edit if I find a source for the computer glitch ... $\endgroup$ – Antzi Oct 22 '18 at 6:40
  • $\begingroup$ Are leaks (explosive or otherwise) a problem if there are no crew on board? It complicates reoccupation, of course. $\endgroup$ – JCRM Oct 22 '18 at 17:01
  • 1
    $\begingroup$ @JCRM it would be bad - very bad - for air-cooled equipment if all the air leaked out. $\endgroup$ – Organic Marble Oct 23 '18 at 3:36
  • $\begingroup$ @uhoh edited with a quote about the 2004 leak, the article explain how they partially automated this task later. $\endgroup$ – Antzi Oct 23 '18 at 3:44

Re: June 2007 computer failure

In June 2007 while the Orbiter Atlantis was docked at the ISS during mission STS-133, all 3 of the Russian segment GNC computers crashed. This left the ISS without the ability to do any propulsive maneuvers, had not the Orbiter been docked.

STS-117 was installing new solar arrays and the Russians were quick to blame power supply problems related to this for the failures. However, investigation showed that the actual problem was poor design of the computer system (which resulted in a zero fault tolerant situation) and their cooling systems (which led to corrosion issues).

In the weeks that followed the crisis and apparent recovery, station commander Fyodor Yurchikhin and his fellow cosmonaut Oleg Kotov disassembled the boxes and cabling and inspected every angle of the hardware, occasionally assisted by their American crewmate, Clayton Anderson. Multiple scopes and probes had failed to find the flaw, but their eyes and fingers eventually did.

The connection pins from the power-monitoring device they'd bypassed earlier, they found, were wet--and corroded. The final report described the ”change in appearance” of fasteners on one box's connectors and noted ”the presence of deposits and residue on the housings, and residue and spots on the contact surfaces.”

Continuity checks found that specific wires, called command lines, in the cable coming out of the device had failed. And one of those lines had short-circuited. Also, in a shocking design flaw, there was a ”power off” command leading to all three of the supposedly redundant processing units. The line was designed to protect the main computers, which are downstream of the power monitor, from power glitches too great for normal power filters to protect against. It does so by turning the computers off when it senses trouble. But in a failure unanticipated by its designers, this one command path itself was able to kill all three processing units due to a single corrosion-induced short.

During the next shuttle mission

During the August shuttle visit, the Russians were able to turn stabilization control over to the American spaceship and tear down their old computer network. The boxes and cables were replaced with fresh units, built and supplied by the European Space Agency and sent up inside a recently launched robot supply ship.

This quote

Multiple scopes and probes had failed to find the flaw, but their eyes and fingers eventually did.

lends credence to the claim that recovery required astronauts on board. Also, the design error which resulted in a loss of redundancy / zero fault tolerance would have kept the ground from simply switching to a different computer.

Note, however, that the ISS was not designed to operate uncrewed for long periods of time, so it is unrealistic to expect it to be able to respond to failures without onboard intervention. See this question and its answers: Why has the ISS not been left unmanned?



Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

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