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Below are two cropped parts of File:ISS-28 Ron Garan prepares the Reentry Breakup Recorder.jpg

In the Unity node of the International Space Station, NASA astronaut Ron Garan, Expedition 28 flight engineer, prepares the Reentry Breakup Recorder (REBR) for installation in the Automated Transfer Vehicle-2 (ATV-2). The ATV-2 is scheduled to undock from the station on June 20, 2011. REBR data improves the understanding of vehicle breakup during reentry, allowing improvements in prediction of the breakup process, increasing the accuracy of estimated casualty expectations, and limiting premature deorbiting of space hardware. In the long term, this research assists in the development of a "black box" for commercial space transportation systems.

The Wikipedia article Reentry Breakup Recorder explains that the device is designed to record data during atmospheric reentry and breakup and then transmits that data before being destroyed upon impact. It then mentions that in one case the recorder survived a water impact and continued to transmit.

I think the copper enclosure shown in the photo might be helpful to redistribute heat and/or to protect electronics from high electric fields and charging from the plasma formed during reentry, but it would not itself survive reentry without some kind of additional covering.

Question: How does a Reentry Breakup Recorder survive reentry and then broadcast its data before impact?

What protected this device from being destroyed during reentry, both the electronics and the antenna necessary for broadcast of the data?

Was there a parachute near the end to extend the time available for broadcast?


Note the anti-static wristband.

enter image description here Source x2

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This fact sheet has some details and a nice image.

enter image description here

The upper dome shaped and the lower cone shaped heat shields are below the copper housing. There is no parachute to extend the time available for broadcast. The copper housing was designed to release REBR as the temperature of the housing increased.

The lower cone shaped heat shield is substantialy thicker than the upper one. This may indicate that the REBR should enter with the cone down and forward.

The copper housing should be removed before using the GPS and Iridium antennas. The antennas should be pointed up towards the GPS and Iridium satellites.

The graphic from this paper shows the altitude-time history of a real reentry.

enter image description here

Data transmission needed 181 seconds, but additional 150 seconds would have been possible.

Recovery of the device is not required after transmitting all recorded data.

Some data:

Mass (REBR alone) – 4 kg Mass (REBR plus protective housing) – 8.6 kg

Dimensions (REBR alone) – 30 cm diameter X 23 cm high Dimensions

(REBR plus protective housing) – 36 cm diameter X 28 cm high

I found some more information about the heat shield shape and its desired orientation in this NASA paper enter image description here

So the probe should orient itself to cone down and forward regardless orientation during release. Note that the center of mass is close to the tip of the cone for both images.

A picture from another paper showing the orientation of the probe with cone down and forward.

enter image description here

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    $\begingroup$ This is fascinating! I'm trying to understand the shape, and the orientation during atmospheric reentry, and during free-fall below 18 km, and the orientation of the antenna, but I can't quite figure out which way it's supposed to point. During free-fall I'd expect the antennas to point up, but that puts it nose-down. However during reentry I'd expect the round shell (the "top" in image) to be pointed forward and down. I'm confused! $\endgroup$ – uhoh Jan 8 at 12:29
  • $\begingroup$ I would have thought the opposite, i.e. that the flatter part (higher part in the image) would orient itself forward/down during the fall. See this: quora.com/… and this space.stackexchange.com/questions/6253/… (the automatic re-orienting depends on the mass distribution, so I might be wrong) $\endgroup$ – BlueCoder Jan 8 at 13:09
  • $\begingroup$ (I was commenting on the device orientiation once it is free from its housing, I don't know which way would be oriented when still connected) $\endgroup$ – BlueCoder Jan 8 at 13:12
  • $\begingroup$ The cone points in the direction of travel; note that it's called the 'forebody' in the text of the image. $\endgroup$ – Organic Marble Jan 8 at 13:38
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    $\begingroup$ Excellent answer Fun fact ... on one of the missions, the REBR vehicle survived impact and continued to transmit for several additional hours while bobbing in the S. Pacific. You could estimate wave height from the GPS data. $\endgroup$ – CoAstroGeek Jan 8 at 23:51

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