A technique that involves pressurization with a radioactive gas has been proposed to solve two problems associated with canisters used to transport samples from remote bodies (planets, moons, asteroids, or comets) back to Earth. The canisters must be sealed at the sampling locations. The problems are how to test the canisters for leakage during transit and how to prevent buckling of the containers from the onset of atmospheric pressure upon return to Earth. The solution to these problems could also be adapted to use on Earth to ensure the integrity of canisters used to store material specimens for long times and to prevent the collapse of sealed canisters that must be brought to or stored at pressures higher than those at which the samples are sealed inside.

According to the proposal, a small container of radioactive krypton (mixed with another suitable pure gas or mixture of gases) would be placed in each sample canister. The container of gas would be equipped with means to release the gas into the interior of the canister soon after the canister is hermetically sealed with the sample inside. A Geiger counter or other radioactivity sensor near the canister would provide an indication of the leakage (if any) of radioactive gas from the canister. The amount of gas provided must be large enough so that the pressure in the canister is sufficient to resist buckling of the canister under ambient atmospheric pressure.

This work was done by Joseph C. Lewis of Caltech for NASA's Jet Propulsion Laboratory. No further documentation is available.

NPO-20446