NASA completes investigation into the failure of the OSIRIS-REx drogue parachute
When the sample return capsule brought OSIRIS-REx’s Bennu samples back to Earth on September 24, 2023, it appeared that the drogue parachute never released prior to the release of the capsule’s main parachutes. Fortunately, those main parachutes were able to do the job, putting the capsule down unharmed but a minute early.
NASA has now completed its investigation into the drogue chute failure. According to its press release:
After a thorough review of the descent video and the capsule’s extensive documentation, NASA found that inconsistent wiring label definitions in the design plans likely caused engineers to wire the parachutes’ release triggers such that signals meant to deploy the drogue chute fired out of order.
The drogue was expected to deploy at an altitude of about 100,000 feet. It was designed to slow and stabilize the capsule during a roughly five-minute descent prior to main parachute deployment at an altitude of about 10,000 feet. Instead, at 100,000 feet, the signal triggered the system to cut the drogue free while it was still packed in the capsule. When the capsule reached 9,000 feet, the drogue deployed. With its retention cord already cut, the drogue was immediately released from the capsule.
In other words, engineers wired the thing incorrectly so it cut its cords before it was released. To further confirm this conclusion engineers will inspect the system thoroughly once scientists have completed removing the Bennu samples from the capsule.
When the sample return capsule brought OSIRIS-REx’s Bennu samples back to Earth on September 24, 2023, it appeared that the drogue parachute never released prior to the release of the capsule’s main parachutes. Fortunately, those main parachutes were able to do the job, putting the capsule down unharmed but a minute early.
NASA has now completed its investigation into the drogue chute failure. According to its press release:
After a thorough review of the descent video and the capsule’s extensive documentation, NASA found that inconsistent wiring label definitions in the design plans likely caused engineers to wire the parachutes’ release triggers such that signals meant to deploy the drogue chute fired out of order.
The drogue was expected to deploy at an altitude of about 100,000 feet. It was designed to slow and stabilize the capsule during a roughly five-minute descent prior to main parachute deployment at an altitude of about 10,000 feet. Instead, at 100,000 feet, the signal triggered the system to cut the drogue free while it was still packed in the capsule. When the capsule reached 9,000 feet, the drogue deployed. With its retention cord already cut, the drogue was immediately released from the capsule.
In other words, engineers wired the thing incorrectly so it cut its cords before it was released. To further confirm this conclusion engineers will inspect the system thoroughly once scientists have completed removing the Bennu samples from the capsule.
