OSIRIS-REx Capsule Landing "Did Not Go...To Plan" - NASA

On September 24, 2023, NASA's OSIRIS-REx spacecraft, which was returning to Earth after having embarked on a historic mission to collect samples from the near-Earth asteroid Bennu; successfully landed its sample return capsule in the Utah desert. The capsule, carrying the precious cargo of rocks and dust gathered from the surface of Bennu, made a safe descent using its main parachute, after an unexpected annomally with the drogue chute during the landing sequence.

The descent, which was expected to follow a carefully planned trajectory, encountered a glitch when a small parachute known as a drogue failed to deploy as anticipated.

NASA engineers have conducted a thorough analysis of the descent video and the capsule's which has revealed a wiring issue in the parachutes' release triggers.Inconsistent wiring label definitions in the design plans were the likely culprits behind the malfunction.

The use of the term "main" was found to be inconsistent between the device sending electric signals and the device receiving them. On the signal side, "main" referred to the main parachute, while on the receiver side, it was a reference to a pyrotechnic device responsible for releasing the parachute canister cover and deploying the drogue.

The glitch resulted in the drogue chute being cut free while still packed inside the capsule at an altitude of 100,000 feet, rather than deploying to slow and stabilize the descent as intended.

At 9,000 feet, the drogue deployed after its retention cord was cut, leading to an unexpected sequence of events. Fortunately, the main parachute deployed as planned and proved robust enough to stabilize and slow the capsule, resulting in a landing over a minute earlier than expected.

Despite the parachute anomaly, NASA has confirmed that there was no negative impact on the OSIRIS-REx mission's primary objective – the safe delivery of the Bennu sample. The agency is now focused on investigating and rectifying the root cause of the parachute malfunction.

To confirm the findings, NASA plans to conduct tests on the parachute release system hardware, currently housed inside one of the glove boxes with the Bennu sample at NASA's Johnson Space Center in Houston. Once the curation team completes processing the sample material, engineers will have access to the hardware and will be able to verify the exact cause of the parachute deployment issue.

The curation of the Bennu sample remains the mission's top priority at this time.