A sample that was collected from the surface of the Bennu asteroid by NASA’s OSIRIS-REx spacecraft was stowed successfully on October 28 in preparation for its journey back to Earth.
The OSIRIS-REx sample stowage procedure had originally been slated for early November. However, images sent back to Earth following the sample collection on October 20 showed that a mylar flap, which had been designed to keep the sample inside the collection head, was wedged open by large rocks allowing the sample to slowly drift into space.
Eager to ensure that the entire sample wouldn’t leak out, the OSIRIS-REx team began the labour intensive stowage procedure on October 24.
Unlike most other robotic spacecraft procedures, the OSIRIS-REx sample stowage procedure is complex requiring near-continuous oversight. This procedure is made all that more difficult with the 330-million-kilometer distance between Earth and the spacecraft resulting in an 18.5-minute signal delay in each direction.
The first element of the procedure requires the careful monitoring of the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) robotic arm to ensure the collection head was placed safely within the Sample Return Capsule (SRC).
“Given the complexity of the process to place the sample collector head onto the capture ring, we expected that it would take a few attempts to get it in the perfect position,” said Rich Burns, OSIRIS-REx project manager at NASA’s Goddard Space Flight Center. “Fortunately, the head was captured on the first try.”
By late October 27, the TAGSAM robotic arm had placed the collection head into the SRC. The OSIRIS-REx team confirmed the collection head had been thoroughly fastened down by commanding the arm to essentially tug on it to see if it would come loose.
Finally, on the afternoon of October 28, the lid of the SRC was closed and two internal latches were fastened.
“I’m very thankful that our team worked so hard to get this sample stowed as quickly as they did,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “Now we can look forward to receiving the sample here on Earth and opening up that capsule.”
The next phase of the OSIRIS-REx mission will see the team prepare for the Earth Return Cruise phase with the spacecraft likely to depart in March 2021. It is then expected to safely return its precious sample back to Earth on September 28, 2023.