For reentry the Space Shuttles lowered their perigee to 28 nautical miles (52 km) above sea level. Shuttle Columbia disintegrated around 60 km altitude, and the first debris fell off as high as 70.5 km. Given the fact that the perigee didn't intersect the Earth, could some debris have made one or two more orbits around the planet?

  • $\begingroup$ I am not sure that you initial assumption is actually correct. While the perigee before entering the athmosphere might have been above sea level, at the time of disintegration the shuttle already did slow down quite a bit due to aerobraking. So the trajectory at that point will most likely have been suborbital, i.e. a perigee intersecting earth. $\endgroup$
    – mlk
    Jan 10, 2022 at 13:08
  • $\begingroup$ @mlk Maybe, just initially the shuttle's perigee was being lowered to 28 nmi for reentry. $\endgroup$
    – user46063
    Jan 10, 2022 at 14:04
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    $\begingroup$ I tried to look it up: Wikipedia mentions a speed of 23,278 km/h just before the beginning of breakup, but the theoretical (without air resistance) minimal orbital speed for that height is somewhere around 28,000km/h, so I think they were already suborbital at that time. $\endgroup$
    – mlk
    Jan 10, 2022 at 15:03

2 Answers 2


No. Even the highest ballistic coefficient debris (engine turbopumps, etc) only made it to Louisiana.

Heavier objects with higher ballistic coefficients, a measure of how far objects will travel in the air, landed toward the end of the debris trail in western Louisiana.

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Source: CAIB Report Volume 1 p. 45 & 47

  • $\begingroup$ So in the report they're absolutely sure no debris kept orbiting? $\endgroup$
    – user46063
    Jan 7, 2022 at 16:35
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    $\begingroup$ @Giovanni it's not explicitly stated in the report - perhaps because it never entered the authors' minds that anyone would have considered it possible. The ballistic coefficient is a measure of how well an object can punch through the atmosphere, and the objects with the highest ballistic coefficients only made it a few hundred miles further. The early debris was tiles with very low ballistic coefficients. $\endgroup$ Jan 7, 2022 at 17:00
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    $\begingroup$ It might be helpful to mentally picture the debris paths from the breakup point to the various impact points. You'll find that light parts have steep paths, the heavy parts have less steep paths, and there's plenty of debris in between. A path that would send a piece of debris far beyond Louisiana would have to be much heavier than the Space Shuttle itself! We can immediately exclude that option. $\endgroup$
    – MSalters
    Jan 10, 2022 at 15:24
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    $\begingroup$ Does the ballistic coefficient even need to come into it? The craft was already at sub-orbital speeds, so unless additional speed was somehow imparted onto a piece of the craft, there is simply no way for it to orbit. It's kind of like how a bouncing ball can never bounce higher than the previous bounce without additional energy from somewhere. $\endgroup$
    – Harabeck
    Jan 10, 2022 at 19:24

Unlikely. From the Wikipedia page on orbital decay:

Due to atmospheric drag, the lowest altitude above the Earth at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately 150 km (93 mi) while the lowest perigee of an elliptical revolution is approximately 90 km (56 mi).

70.5 km is well below that. On that same page there is a link to an open-source software package that allows you to simulate orbital decay, if you are interested to model this further (I have not used the software myself).

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    $\begingroup$ The 150 km / 93 mi value for a circular orbit is outdated since the satellite Lixing-1 orbited in a 124 km x 140 km orbit for more than three days. space.skyrocket.de/doc_sdat/lixing-1.htm And Jonathan McDowell lists high-elliptical Molniya sats that survived 70 km perigees. I guess the Wikipedia values rather mean any spacecraft can orbit at these altitudes, but some can so at lower ones. $\endgroup$
    – user46063
    Jan 7, 2022 at 12:52
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    $\begingroup$ @Giovanni re: Lixing-1, same website also says "It likely features some kind of propulsion to lower the orbit and to maintain the low orbit." and it looks suspiciously like ESA's GOCE spacecraft that did the same (use propulsion to sustain a low orbit, albeit much higher). $\endgroup$ Jan 7, 2022 at 16:02

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