Frequently Asked Questions
- Why do satellites fall from orbit?
- Why does space hardware come apart during reentry?
- Are there examples of objects that have survived reentry?
- How much material from a satellite will survive reentry?
- What is a "debris footprint?"
- Can we predict where debris will land?
- Can we control where debris will land?
- Has anyone been hit by falling debris?
- How fast will debris be moving when it lands?
- What is the overall risk from reentry debris?
- Why do reentering bodies experience extreme heating?
Spacecraft Reentry FAQ:
Are there examples of objects that have survived reentry?
More than 50 debris objects have been recovered and documented over the years (see recovered debris), and there are several noteworthy examples from recent reentries.
On January 22, 1997, a Delta second stage reentered and four objects were recovered: a 250-kg stainless steel tank, a 30-kg pressure sphere, a 45-kg thrust chamber, and a lightweight piece which struck but did not injure a woman.
On April 27, 2000, a Delta second stage used in the launch of a Global Positioning System (GPS) satellite reentered and debris impacted near Cape Town, South Africa. The recovered debris was nearly identical to that recovered in Texas.
In general, components made of aluminum and similar materials with low melting temperatures do not survive reentry, while pieces or components made of materials with high melting temperatures, such as stainless steel, titanium, and glass often do survive. Large pieces with moderate melting temperatures can also survive reentry, radiating heat over their large surface areas. Pieces that survive reentry tend to be large and in some cases heavy, posing a significant hazard to any people and property within the bounds of the object's reentry debris footprint.
It is interesting to note that even low melting temperature materials can survive under the right circumstances. For example, a lightweight piece that comes off of the parent body early in the reentry may not see sufficient heating to melt, and another object contained within the body of the satellite and protected by surrounding structure through most of the reentry may also survive.
Further questions? Contact us at cords@aero.org .
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| The thrust chamber and related debris for the Delta stage was also recovered. It now resides in a UFO museum in Texas. (Aerojet) | One object recovered from the reentry of the Delta second stage into Texas was this 250-kg propellant tank. (NASA) | This 30-kg sphere (which contained a gas used to pressurize the fuel tank) was found 105 km from the large tank. (NASA) |
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| Ms. Lottie Williams was struck by this small piece of debris. (Tulsa World) | Thrust chamber recovered in South Africa. (Die Burger/Antonie Robertson) |
Delta second stage propellant tank recovered in South Africa. (Die Burger/Johann van Tonder) |
Pressure sphere recovered in South Africa. (Argus/Enver Essop) |
