Oct. 29 (UPI) -- The asteroid sample collected by NASA's OSIRIS-REx spacecraft early this month has been safely secured in its return capsule.
"We had originally planned to conduct the stow operation next week, but we're here to announce today that we've successfully completed that operation," Rich Burns, OSIRIS-REx project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said during a press conference on Thursday.
Last week, mission engineers were reviewing images of the spacecraft's sample collection head, the TAGSAM, when they noticed escaping particles.
It turns out, the sample head was so full that a valve called the mylar flap -- designed to allow particles into the collection head but not out -- had gotten jammed.
Instead of going ahead with maneuvers intended to precisely measure the sample's mass, mission engineers decided to expedite the sample stow operation.
"Our team quickly redesigned the entire timeline for the stow campaign, which was extremely difficult," Burns said. "It takes approximately 37 minutes just to confirm that a command has been received by the spacecraft."
Because of this time-delay in communications between the craft and mission control, and the methodical nature of the stow operation, members of the OSIRIS-REx mission team had to work around the clock.
To ensure each step of the stow operation was completed properly, engineers routinely paused to take photographs and examine their progress. The process involved precisely positioning the TAGSAM's collector head into the Sample Return Capsule, or SRC, closing it and then conducting tests to ensure it was securely sealed and ready for the trip back to Earth.
"We wanted to only attempt the stow operation one time and make sure we were successful, and we definitely were," Sandy Freund, a mission support manager for OSIRIS-REx at Lockheed Martin, said during the press conference.
Images collected before and during the stow procedure suggest the collection head only leaked particles when it was in motion -- as a result of what engineers called a salt-shaker effect. When spacecraft's robotic arm and TAGSAM remained motionless, the asteroid sample material remained inside the collection head.
"I was of course concerned about the loss of particles," said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. "Every one of those particles is scientifically valuable."
However, Lauretta and the rest of the team said they were confident that there was plenty of sample ready to be returned to Earth for scientific analysis.
"Everywhere that we can see into the TAGSAM, we can see an abundance of sample materials," Lauretta said. "We are confident that we still have hundreds of grams of sample that we plan to bring back to Earth."
NASA plans to send OSIRIS-Rex and its asteroid sample on its journey home early next year, but the craft is currently 200 million miles away. The sample won't make its way to Earth's surface until the end of 2023.
