OSIRIS-REx Interest Grows as Launch Day Nears
There's nothing like the great unknown to capture the imagination of scientists and science fans alike, and the UA-led OSIRIS-REx asteroid sample return mission holds plenty of suspense for both groups.
If the questions posed at Saturday's Lunar and Planetary Laboratory open house were any indication, then Tucsonans are impressively up to speed on the OSIRIS-REx mission and eagerly anticipating the spacecraft's launch on Sept. 8 in Florida.
A near-capacity auditorium crowd of all ages at the Kuiper Space Sciences building wanted to know about everything from the spacecraft's solar panels to the pressurized nitrogen that will be used in collecting a sample from the near-Earth asteroid Bennu.
University of Arizona scientists Bashar Rizk, Carl Hergenrother and Michael Nolan shared their perspective in a panel discussion on various aspects of the mission. They were followed by the mission's deputy principal investigator, Ed Beshore, whose hourlong overview filled in any gaps.
The result was a wealth of information that could be appreciated by laypeople and space geeks alike. But it's what the scientists don't know or expect that really fires the imagination — both theirs and ours.
The billion-dollar NASA mission, on the drawing boards at the UA since 2004, is certain to yield unexpected results, according to Nolan, an asteroid scientist.
"In any mission, you have to predict what you will find," Nolan said, "and we predict we’ll find pristine material related to the origin of life.
"However, in every other mission, we've predicted and been wrong on things — and that's why we do this. We'll be finding things we don't know anything about."
The sample will be the grand prize, and Beshore called it "a gift to future scientists (who will be) using techniques we haven't dreamed of yet." The mission represents "a turning of the corner" in the way that the planets are investigated, he said.
Rizk noted that the weekend marked the one-year anniversary of the installation and integration of the UA-designed OSIRIS-REx Camera Suite, or OCAMS, which will be the spacecraft's eyes in the sky.
The three cameras are known informally as PolyCam, a "spyglass" that will spot Bennu from hundreds of thousand of miles and investigate its surface features; MapCam, which will map the entire surface of the asteroid from about three miles, in color; and SamCam, the spacecraft's "peripheral vision" that will image the actual sample event, expected to occur in July 2020.
"We're hoping this asteroid will surprise us in the way that so many images have in the past," said Rizk, who was the lead on OCAMS.
Hergenrother, the astronomy lead, detailed the process of elimination that fixed on Bennu as the target. The asteroid, which is 148 million miles away, was chosen because of its carbonaceous composition ("Material that has had a minimal amount of change," he said), Earth-like orbit, moderate rotation and size.
"We're going to learn so much about asteroids that we'll be able to apply to other (space) objects," Hergenrother said.
The OSIRIS-REx spacecraft will have three tries to retrieve the sample, expected to yield between 60 grams and a couple of pounds of Bennu's regolith, or loose surface material. An instrument known as TAGSAM — which stands for Touch-and-Go Sample Acquisition Mechanism — will be used for the collection. If all goes well, the sample will return to Earth at the Utah Test and Training Range, about 80 miles west of Salt Lake City, in September 2023.
What happens, one questioner wanted to know, if TAGSAM muffs the first try?
"We'll have to go to Washington and show them a lot of PowerPoint," Beshore said, his sense of humor still intact with less than two weeks to go before launch.
For more about the OSIRIS-REx mission, go to asteroidmission.org. The spacecraft is expected to launch at about 4 p.m. (Arizona time) on Sept. 8 from Kennedy Space Center in Cape Canaveral, Florida.
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University of Arizona in the News