OSIRIS-REx sets out to touch an asteroid
By Jan Wondra
It’s a small matter of setting out across time and deep space to reach a piece of rocky space debris whose 500-meter diameter is about the length of five football fields, then orbit it for several months while picking the perfect spot to touch lightly down, gather up some material from the surface and bring it back to Earth.
The asteroid, for that, is what it is, is known as Bennu. The vehicle that will accomplish this feat is known as OSIRIS-REx, and it has been designed and built in Colorado by Lockheed Martin engineers in their Waterton Canyon facility.
“Our mission goal is to successfully bring back a sample of the asteroid,” said Timothy Linn, chief systems engineer for the OSIRIS-REx project. “But our real goal is to understand our origins and to understand how this near-Earth object operates, which can improve the safety of future space missions.”
The OSIRIS-REx unmanned space vehicle being built in Waterton Canyon is nearly complete. It will ship out to Cape Kennedy Space Center in May and it is scheduled to launch Sept. 8.
“We have a 39-day launch window,” said Gary Napier, of the mission’s Civil Space Communications. “That allows some leeway for bad weather in Florida. And there is some symbolism in that our planned touch-and-go on the asteroid is July 4, 2020.”
The trajectory of the launch to what is considered a B-class asteroid is carefully planned. The mission marks only the fourth time that NASA has set out to capture space materials, the others being the Apollo moon missions and the Stardust mission which captured comet materials. This launch is important for another reason; the launch and the entire mission will be operated here in Colorado by systems engineers based in Waterton Canyon.
“The launch from Earth is a fly-by-the-moon that gives us extra energy, a boost toward the asteroid,” said Linn. “Bennu is one of the best known near-Earth objects, among thousands of near-Earth objects. We know a lot about it now because we’ve got a resolution to about three meters, the general topography, but we’ll know more about it once we get there, the mineral content, the shape, and size of particles.”
Mission engineers describe the collection arm as “a sort of pogo stick. It’s got a spring in the middle of its forearm that will absorb the impact of touching the asteroid so that it doesn’t bounce off.”
“We’ll orbit for several months to pick a touch site, then in a matter of five seconds, pick up a 60-gram sample, about two ounces,” Linn said. “This is actually a huge sample size that will be distributed to several research facilities in the U.S. and Canada, which has collaborated on the project. We’ll correlate the findings with five other systems, including two spectrometers. One is NASA”s Goddard [spectrometer]; the other is at the University of Arizona.”
The enormity of the mission cannot be underestimated, according to Lockheed Martin.
“This is a 4.5 million-year-old time capsule from the early formation of our solar system,” Napier said.
“The ‘s’ in OSIRIS-REx is for security,” Linn said. “The routes of these small bodies change over time. In fact, solar energy hitting an asteroid can change the orbits of these objects, possibly bringing them into a path crossing a planet’s orbit, and we need to understand that.”
That is a way of saying that if that were to happen and an asteroid threatened life as we know it on Earth, we would need a way to stop it. The entire mission is forward-looking.
“The idea of asteroid retrieval missions is not as far-fetched as you’d think,” Linn said. “There are private companies waiting in the wings.”
The perception that aerospace engineers have been dreaming of space since childhood isn’t far off either.
“I was always interested in motors and things that moved,” Linn said. “That led me to rockets and launching things, which led me to engineer at CU Boulder, which led me here. OSIRIS-REx is my most exciting project to date, but I’ve worked on the Phoenix Mars Lander, the study of the dark side of the moon. I worked on Genesis.”
Lockheed Martin has made it easy to follow the progress of this Colorado-based mission. It’s website www.asteroidmission.org features a startling image of Bennu rotating in space.
“This mission is exciting,” Linn said. “We’re bringing back a sample of an asteroid. Exploring these small bodies, with the potential future of human missions, is a path forward for human space exploration.”