NASA believes it has discovered why the OSIRIS-REx asteroid probe’s return capsule failed to deploy its drogue parachute as planned during its descent through Earth’s atmosphere on September 24th.
The problem did not prevent the capsule from making a safe and soft landing that day, but it was probably caused by wire crosstalk.
“After a thorough review of the descent video and extensive documentation of the capsule, NASA found that due to inconsistent definitions of wiring labels in the design plan, engineers were unable to wire the parachute release trigger and deploy the drogue chute. “We found that the signals for this purpose were likely not fired out of order,” the agency official wrote. Tuesday’s blog post (December 5th).
“In the system design plans, the word ‘main’ was used inconsistently between the device transmitting the electrical signal and the device receiving the signal,” they added. “On the signal side, ‘main’ meant the main parachute. By contrast, on the receiver side, ‘main’ meant the pyrotechnics that released the cover of the parachute canister and ignited it to deploy the drogue.” The engineer connected the two.” The main power supply is cut off and the parachute deployment action is taken out of sequence. ”
Related: NASA’s OSIRIS-REx lands samples from asteroid Bennu on Earth after historic 4 billion mile journey
The drogue chute was to be deployed at an altitude of 100,000 feet (30,000 meters) and served to slow and stabilize the return capsule’s descent prior to deployment of the main chute at approximately 10,000 feet (3,000 meters). .
However, as a result of a wiring problem, the drogue’s retention cord was severed during deployment, leaving the chute within the capsule. The drogue remained there until the capsule reached an altitude of 9,000 feet (2,740 m) and the main chute opened. At that point, the drogue took to the air and fell, with nothing holding the capsule.
But the main chute overcame that problem. “The design was robust enough to stabilize and decelerate the capsule, allowing it to land safely more than a minute earlier than expected,” NASA officials said in a statement. “There were no adverse effects on the OSIRIS-REx Bennu sample as a result of the unexpected drogue deployment.”
Bennu is a near-Earth asteroid visited, studied, and sampled by OSIRIS-REx. The material the spacecraft captured from Bennu’s surface in October 2020 is currently being processed at NASA’s Johnson Space Center (JSC) in Houston.
Once that’s done, researchers around the world will study the samples to learn more about the early days of our solar system and the role carbon-rich asteroids like Bennu played in bringing the building blocks of life to Earth long ago. You’ll have to look for clues.
NASA officials said the return capsule’s parachute release system is in a protective glovebox alongside the JSC’s Bennu sample. “Once the on-site curation team completes processing the sample material (currently the mission’s highest priority), NASA engineers will be able to access the parachute hardware to verify the cause,” they wrote. ing.