WASHINGTON – The Five-Week Part-Time Shutdown This year, NASA's missions may have provided a representative of a troubled instrument on the agency's next Mars mission.
During a March 27 presentation to the National Academy's Committee on Astrobiology and Planetary Science, Ken Farley, project scientist for the Mars 2020 rover, said NASA directed the mission last December to conduct a "termination / continuation" review for Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC), one of the instruments on the rover.
"It was a combination of technical challenges and high cost risk
That review was originally scheduled for early January, he said, but was delayed by the five-week par tial government shutdown that started Dec. 22, curtailing all but essential agency activities. The review took place in late January and early February, after the shutdown ended.
"We've just finished doing some of the technical challenges" during that time, Farley said. After the review, SHERLOC, with "minor delays to the procedures that are used to minimize further cost growth and minimize the schedule risk."
but its lower its technical risk and cost.
The instrument, mounted on the rover's arm, carries a set of spectrometers, a camera and a laser to study Martian rocks.
Farley, speaking the committee by telecon, said that the spectrometer component of the instrument is scheduled for delivery to the Jet Propulsion Laboratory in this summer for integration onto the spacecraft. There are backup plans, though, with the release of the instrument to be shipped to Cape Canaveral, Florida, next January for a July 2020 launch.
He did not elaborate on the details of the instrument problem but said it had a high-voltage power supply for its laser. "If I could convey one message to the science community, it is to think deeply about high-voltage power supplies on Mars, because they have been a real problem for us," he said. "Mars is a terrible environment for such voltages, so we have trouble with arcing."
SHERLOC was one of those reasons cited by NASA for the mission's cost overrun. The agency, in its full fiscal year 2020 budget request March 1
NASA has not provided further details on that. Lunar and Planetary Science Conference March 18, Lori Glaze, director of NASA's planetary science division, said the cost growth was less than 15 percent of the overall cost – $ 2.1 billion plus $ 300 million for its first Martian Year of operations – and that the costs would come out of other parts of the overall Mars program. The agency's fiscal year 2019 operating plan, yet to be released, seeks to contain details of those costs.
Other aspects of the mission are faring well. The heat shield that will protect the rover during entry into the martian atmosphere has been rebuilt after the original unit cracked during testing last year. "The new build on schedule," he said, and is scheduled for delivery this summer. Mechanical actuators for various parts of the rover, components that cause problems for the development of the Curiosity rover.
A key part of the Mars 2020 mission wants to test samples of Martian rocks and soil for return to Earth by future missions.
Previous planning called for the rover to leave the sample canisters on the surface as it roves, requiring a future mission to pick them up with its own rovers. Farley said the mission is now thinking about going back to its original plan to carry the cached samples on the rover.
"We're having the group of people that are thinking about how to do that," he said of planning for collecting and returning samples. "In particular, how can Mars 2020 best handle its sample cache?
Farely adding there's no urgency in selecting a method for caching samples. "The beauty of this design is not up to date, because the hardware is capable of doing any combination or carrying everything on the ground or splitting it up," he said. We do not put them down when we're on Mars. "