We have all been there, had that one stubborn jar of jam that we just can’t open. Maybe you grab a rubber band or run it under warm water and its an easy fix but just imagine when the jar is a module from a $1.16 billion interplanetary probe! That’s what happened to NASA engineers when they were trying to recover samples from the OSIRIS-REx module when they discovered the clamps had cold welded shut!
OSIRIS-REx is a NASA mission to retrieve a sample from asteroid Bennu and return it to Earth. The probe launched in September 2016 in what was a complex and audatious mission. In order to collect the samples the probe ‘kissed’ the surface at just the right trajectory and velocity so not to be destroyed and to return them, OSIRIS-REx completed a flyby manouvre of Earth and dropped them off before continuing on to a new destination. Impressive stuff.
The samples were successfully returned to Earth on 24 September 2023 having been deployed high above the Earth’s atmosphere. The capsule then gracefully floated down under a parachute to the Department of Defense’s Utah Test and Training Range. The samples that were contained within will help us to better understand how the planets formed, how life began and to improve our knowledge of asteroids and just how we might be able to defend ourselves from future potential impacts.
Having successfully completed the sample collection and recovery, it seems that getting the samples out of the capsule was destined to be the more challenging aspect. When the engineers tried to open the sample head of the Touch and Go Sample Acquisition Mechanism they quickly learned that two of the 35 fastenings had cold welded themselves shut!
Unfortunately, the team did not have any ready made tools for such a situation so they had to improvise and created their own new tool from a special non-magnetic stainless steel. If this wasn’t hard enough, the team’s challenge was exaserbated because of the lack of space in the container that the samples and the capsule were stored within. This process was a laborious one though as the team had to test and refine the tool and instrument many times to minimise risk of damage and contamination.
Success was limited as the team were only able to recover 70 grams of the asteroid sample although this was in excess of the target 60 grams. The science teams are now working with some of the samples and have hermetically sealed the rest for future studies.