NASA believes it knows why the return capsule of the OSIRIS-REx asteroid probe failed to deploy its parachute as planned during its descent through Earth’s atmosphere on September 24.
The problem, which did not prevent the capsule from landing safely and quietly that day, was likely caused by crossed wires.
“After extensive review of the landing video and extensive documentation of the capsule, NASA found that inconsistent definitions of wiring labels in the design plans likely caused engineers to wire the parachute launch actuators so that signals intended to deploy the chute were triggered out of order,” he wrote. Agency officials at A Tuesday’s blog post (December 5).
They added, “In the design drawings of the system, the word ‘main’ was used inconsistently between the device that sends the electrical signals and the device that receives the signals.” “On the signal side, ‘main’ meant the main parachute. In contrast, on the receiving side, ‘main’ was used as a reference to the fireworks being fired to release the parachute case cover and deploy the parachute. Engineers connected the two, resulting in a malfunction In parachute deployment procedures.”
Related: NASA’s OSIRIS-REx rover lands samples from asteroid Bennu to Earth after a historic 4-billion-mile journey.
The chute was supposed to be deployed at an altitude of 100,000 feet (30,000 m), helping to slow and stabilize the return capsule’s descent before deploying the main chute at an altitude of about 10,000 feet (3,000 m).
However, as a result of the wire problem, the anesthetic retention wire was cut at the time of deployment, leaving lubricant in the capsule. The drug remained there until the capsule reached an altitude of 9,000 feet (2,740 m), when the main chute opened. At that point, the drug jumped into the air and fell away, with nothing holding the capsule down.
But the main lubricant overcomes the problem. “Its design was strong enough to stabilize the capsule and slow it down, resulting in a safe landing more than a minute earlier than expected,” NASA officials wrote in the statement. “There was no adverse impact on the OSIRIS-REx Bennu sample as a result of unexpected drug deployment.”
Bennu is the near-Earth asteroid that OSIRIS-REx visited, studied, and sampled. Material that the probe picked up from Bennu’s surface in October 2020 is now being processed at NASA’s Johnson Space Center (JSC) in Houston.
Once that’s done, researchers around the world will study the sample, looking for clues about the early days of the solar system and the role carbon-rich asteroids like Bennu may have played in bringing the building blocks of life to Earth long ago.
The return capsule’s parachute release system is inside a protective glove box next to the Bennu sample at JSC, NASA officials said. “Once the processing team there completes processing the sample material — the mission’s top priority at the moment — NASA engineers will be able to access the parachute’s hardware and investigate the cause,” they wrote.
