Crossed wires led to high drama when NASA returned asteroid samples to Earth

Crossed wires led to high drama when NASA returned asteroid samples to Earth

Zoom in / The OSIRIS-REx sample return capsule, with its main parachute nearby, shortly after landing in Utah on September 24, 2023.

Keegan Barber/NASA

This was the moment Dante Lauretta had been waiting to see for nearly 20 years. A small robotic capsule on its way back to Earth contained rocks captured from an asteroid, and Lauretta was eager to get his hands on the samples.

Led by Lauretta, scientists carefully designed a billion-dollar mission to bring back pieces of a carbon-rich asteroid believed to contain organic molecules, the building blocks needed for life to arise. This NASA mission, known by the acronym OSIRIS-REx, blasted off from Earth in 2016, collected samples from a roughly 1,600-foot-wide (500-meter) asteroid called Bennu in 2020, then set a course to return to Earth.

On September 24, the OSIRIS-REx spacecraft released the canister containing the asteroid samples to plunge into Earth’s atmosphere, while the parent vehicle headed onto a trajectory to return it safely to deep space for a follow-up mission to explore a different asteroid at the end of 2020.

Loretta, the principal investigator for OSIRIS-REx from the University of Arizona, was a passenger in a US military helicopter flying around the capsule’s landing zone in the Utah desert. A heat shield protected the capsule from temperatures reaching more than 5,000 degrees Fahrenheit during reentry.

Next, a small parachute was supposed to open to stabilize the 32-inch (81 cm) wide reentry vehicle. After about five minutes, a larger main chute will open to slow the capsule down for a gentle landing while protecting the precious asteroid material trapped inside.

At least, that was the plan. As OSIRIS-REx returned its asteroid sample safely to Earth, there were moments of high drama.

out of control

For those watching NASA’s live video coverage of the OSIRIS-REx mission’s return to Earth, there were hints that something was wrong. Video images taken by a NASA tracking plane showed the capsule descending towards Earth at high speed, long after the point where the parachute was supposed to be visible.

Inside a nearby helicopter, Loretta waited for verbal updates on the capsule’s condition.

“I “I heard the 100,000-foot crossing, and there was no anesthetic, and the anesthetic chute is supposed to come out at 100,000 feet,” he recalled during a presentation last month to the National Academies’ Space Studies Council. “Sixty thousand feet, there’s no drug. I’m like, ‘Oh, that’s not good.'”

The last time NASA tried to bring extraterrestrial samples to Earth, the parachute never opened. The robotic Genesis mission ended in an out-of-control impact in Utah, tearing apart the capsule, sending back microscopic particles collected from the solar wind. Scientists were able to save some samples, but it was not easy.

Loretta described an accident like the one on NASA’s Genesis mission as a “worst case scenario” for OSIRIS-REx. In this case, scientists will need to collect as much of the asteroid sample as possible from the Utah desert. Anything salvaged must be carefully examined to ensure it has not been contaminated with Earth’s soil and life forms.

You can watch a replay of OSIRIS-REx’s landing below.

“We are faltering,” Loretta said. “We are in a subsonic regime, and we are not stabilizing.” “There’s no anesthetic chute deployed here. Problem! So I was trying to mentally prepare myself, because we’re watching live TV, to get off this helicopter and deal with a capsule that crashed in the desert.”

Next, Loretta heard confirmation from the Air Force that the OSIRIS-REx reentry capsule had opened its main parachute.

“I was saying what? How is that possible?” he said. “So the main parachute deployed. And the drogue parachute, as we were able to reconstruct it, moved a second before the main parachute. And so it came out. It had to be ejected. It was in front of the main parachute in the canister, and it seemed like there was a problem with the circuit.”

NASA provided a more detailed description Tuesday of the problem that prevented the anesthetic cascade from being deployed on time.

The capsule was supposed to send an automated signal to deploy the drug chute at 100,000 feet, starting a roughly five-minute timer before a second signal cut the parachute’s retaining cord, allowing the larger parachute to open and complete the descent sequence. Instead, at 100,000 feet, the signal prompted the system to cut off the anesthetic while it was still packed inside the capsule, according to NASA.

At 9,000 feet, the other signal sent the order to actually release the dope chute. But with the retaining rope already cut, the anesthetic was immediately released from the capsule, and the main parachute opened as expected.

“The first signal was supposed to fire a mortar round and release the drug,” Loretta said. He added, “The second signal was supposed to cut the cable to free the main cable… It seems that the first signal cut (the cable), and then the second signal fired the mortar shell, so it went back. But it succeeded. We had a lot.” “I landed safely on the side of this main chute. I landed safely – a beautiful, precise landing in the Utah desert.”

An investigation by engineers from NASA and Lockheed Martin, which built the OSIRIS-REx spacecraft and the return capsule, found that mission construction plans were not specific enough in guiding the technicians who assembled the return capsule.

“In the system design plans, the word ‘main’ was used inconsistently between the device that sends the electrical signals and the device that receives the signals,” NASA said in a written statement. On the signal side, “main” meant the main parachute. In contrast, “main” on the receiver side was used as a reference to the pyrotechnics fired to release the parachute case cover and deploy the parachute.

“Engineers connected the two main streams, causing a disruption in parachute deployment operations,” NASA said.

Scientists continue to analyze asteroid material transported by the OSIRIS-REx rover, Loretta said.

In a preliminary analysis of some of the dust, scientists found approximately 5% carbon by mass, and the material contains abundant water in the form of moist clay minerals. It is very plausible that asteroids like Bennu transported the vast majority of the water now found in Earth’s oceans, lakes and rivers billions of years ago.

The team tasked with retrieving samples from the capsule at NASA’s Johnson Space Center in Houston had trouble opening some of the fasteners sealing the asteroid’s material into the main collection chamber. While the team was working on a new plan to collect all of the asteroid’s samples inside, it used tweezers to pull out some of the larger pieces, including a roughly 1.2-inch-long (3-centimetre) fragment directly from Bennu.

“Organic chemistry sounds great,” Loretta said.

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