Two days after touching down on asteroid Bennu, NASA’s OSIRIS-REx mission team received on Thursday, Oct. 22, images that confirm the spacecraft has collected more than enough material to meet one of its main mission requirements — acquiring at least 2 ounces (60 grams) of the asteroid’s surface material.
The spacecraft captured images of the sample collector
head as it moved through several different positions. In reviewing these
images, the OSIRIS-REx team noticed both that the head appeared to be full of
asteroid particles, and that some of these particles appeared to be escaping
slowly from the sample collector, called the Touch-And-Go Sample Acquisition
Mechanism (TAGSAM) head. They suspect bits of material are passing through
small gaps where a mylar flap — the collector’s “lid” — is slightly wedged open
by larger rocks.
“Bennu continues to surprise us with great science and
also throwing a few curveballs,” said Thomas Zurbuchen, NASA’s associate
administrator for science at the agency’s headquarters in Washington. “And
although we may have to move more quickly to stow the sample, it’s not a bad
problem to have. We are so excited to see what appears to be an abundant sample
that will inspire science for decades beyond this historic moment.”
The team believes it has collected a sufficient sample
and is on a path to stow the sample as quickly as possible. They came to this
conclusion after comparing images of the empty collector head with Oct. 22
images of the TAGSAM head after the sample collection event.
The images also show that any movement to the
spacecraft and the TAGSAM instrument may lead to further sample loss. To
preserve the remaining material, the mission team decided to forego the Sample
Mass Measurement activity originally scheduled for Saturday, Oct. 24, and
canceled a braking burn scheduled for Friday to minimize any acceleration to
the spacecraft.
From here, the OSIRIS-Rex team will focus on stowing
the sample in the Sample Return Capsule (SRC), where any loose material will be
kept safe during the spacecraft’s journey back to Earth.
“We are working to keep up with our own success here,
and my job is to safely return as large a sample of Bennu as possible,” said
Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona
in Tucson, who leads the science team and the mission’s science observation
planning and data processing. “The loss of mass is of concern to me, so I’m
strongly encouraging the team to stow this precious sample as quickly as
possible.”
The TAGSAM head performed the sampling event in
optimal conditions. Newly available analyses show that the collector head was
flush with Bennu’s surface when it made contact and when the nitrogen gas
bottle was fired to stir surface material. It also penetrated several centimeters
into the asteroid’s surface material. All data so far suggest that the
collector head is holding much more than 2 ounces of regolith.
OSIRIS-REx remains in good health, and the mission
team is finalizing a timeline for sample storage. An update will be provided
once a decision is made on the sample storage timing and procedures.
NASA’s Goddard Space Flight Center in Greenbelt,
Maryland, provides overall mission management, systems engineering and the
safety and mission assurance for OSIRIS-REx. Lockheed Martin Space in Denver
built the spacecraft and is providing flight operations. Goddard and KinetX
Aerospace of Tempe, Arizona, are responsible for navigating the OSIRIS-REx
spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program,
which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama,
for the agency’s Science Mission Directorate in Washington.
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