This question was prompted by articles mentioning that a majority of Space Shuttle launches had scrubbed launches.

Which STS mission had the largest amount of accidents and/or failures?

If relevant, this question may be separated into categories like on-pad scrubs and in-flight issues that did not result in mission aborts.

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    $\begingroup$ I don't have a good sense of all the Shuttle missions, but STS-93 seems like it deserves a mention $\endgroup$
    – Erin Anne
    Commented Nov 21, 2022 at 0:00
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    $\begingroup$ The "largest amount of ...failures" is boring anyway. It will be a long litany of chipped tiles and stuck middeck locker doors. Ask about the most impactful failures. That would be a fun answer to write. $\endgroup$ Commented Nov 21, 2022 at 1:25
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    $\begingroup$ @OrganicMarble I can guess that answer “yeah so this one blew up right after launching” $\endgroup$
    – Topcode
    Commented Nov 21, 2022 at 14:40
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    $\begingroup$ @Topcode excellent point. The most impactful non-fatal failures. $\endgroup$ Commented Nov 21, 2022 at 14:40
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    $\begingroup$ @OrganicMarble The majority having leak issues was bad memory on my side. I remembered this paragraph from Ars Technica wrong "Over its lifetime, due to this complexity, the shuttle on average scrubbed nearly once every launch attempt. Some shuttle flights scrubbed as many as five times before finally lifting off. For launch controllers, it never really got a whole lot easier to manage the space shuttle's complex fueling process, and hydrogen was frequently a culprit." $\endgroup$ Commented Nov 21, 2022 at 23:18

1 Answer 1


I assume you don't count the Challenger and Columbia disastors, otherwise those win. Assuming you don't I can't decide which one as they had different types of problems but here are some troubled missions:

  1. STS-93:It was scrubbed three times before launch. Then it launched without 897 lb of LOX. Then, the wiring failed and caused problems with a bunch of sensors. Finally, there was a deactivated LOX post in the main injector. Of course, the biggest of all was that, during ingnition, a gold pin hit the nozzle extension, causing a nozzle leak. Due to a bunch of luck, disaster was averted. There are more, but those were the biggest.
  2. STS-26: The flight after the Challenger disaster. It was scrubbed once before launch. A couple of problems occured. First, the FES (Flash Evaporator System) iced up and shut down leaving the crew in a shuttle with temperatures of around 87°F (31°C) until day 4 of the mission. Second, a Ku-band antenna deployed on day 2 but failed to respond. Gradual improvement.
  3. STS-27:During the ascent, it appears that a piece of foam hit the shuttle, like in the Columbia disaster. The crew believed it to be unsurvivable. Luckily for them, the tiles that they hit covered something else that was steel, and therefore it didn't burn up on reentry. Lucky break. Gradual worsening.
  4. STS-28:1 launch delay. First, a pyro initair circuit had an issue and failed. Then, an Exhaust Temp had an issue. Next, a regulator pressure dropped. Also, some recorders had issues, as did a camera which couldn't focus. Additionally, measuerer fuel was malfunctioning, as was the pitch and yaw actuators. The TPS (Thermal Protection System) also sustained some damage, although that is common. Then, a fuel cell's sensor failed. Also, the side hatch wasn't working as was very hard for the crew to operate. Finally, an airlock pin did not latch. Improvement, but a bunch of annoying minor issues.

Fortunately, STS-29 did not have any notable issues (about time). So, these are what I would call some of the 3 biggest cursed launches of the shuttle program.

  • $\begingroup$ You left out the main failure on STS-93, the nozzle leak. Read the part about the LOX post again. $\endgroup$ Commented Mar 21, 2023 at 12:02
  • $\begingroup$ Done. @OrganicMarble $\endgroup$ Commented Mar 21, 2023 at 20:14
  • $\begingroup$ Speaking of clear communication, did STS-28 have any notable issues or not? "Fortunately, STS-28 did have any notable issues (about time)." $\endgroup$ Commented Mar 21, 2023 at 23:14
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    $\begingroup$ I don't think you are getting the point here. STS-29 had 12 or so significant anomalies according to the Missions Summary. The question wants to know "Which STS MIssion". That means the answer will be one mission, the one with the most failures. Also your writeup on STS-28 is awful, you clearly didn't understand anything you read in the Summary. What in the world does "measuerer fuel was malfunctioning" mean? Downvoted. $\endgroup$ Commented Mar 22, 2023 at 11:45
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    $\begingroup$ Thank you for the answer! However I wasn't asking for examples of missions that had multiple major issues, but rather the one with the most setbacks, even minor ones (but still made it to official documents). As @OrganicMarble mentions, that would be only one mission (possibly per category), and the failure count has at least one more digit than what you mention. $\endgroup$ Commented Mar 22, 2023 at 19:03

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