OSIRIS-REx at Bennu
NASA's OSIRIS-REx spacecraft will attempt to collect samples from the surface of asteroid Bennu for return to Earth. Credit: NASA

KENNEDY SPACE Center, Fla. — NASA managers have given their approval for the launch Sept. 8 of an Atlas 5 carrying a spacecraft that will travel to a nearby asteroid, collect samples and return them to Earth.

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer, or OSIRIS-REx, mission passed a launch readiness review Sept. 6, the last major review prior to its launch from Cape Canaveral at 7:05 p.m. Eastern Sept. 8. A weather forecast projects an 80 percent chance of acceptable weather for launch.

NASA and United Launch Alliance officials said at a pre-launch briefing here Sept. 6 that there were no issues they were dealing with prior to the scheduled launch. They also emphasized that last week’s Falcon 9 explosion at Space Launch Complex 40, less than two kilometers from the building where the Atlas 5 and OSIRIS-REx are being prepared for launch, would not affect the mission.

Tim Dunn, the NASA launch director for the mission, said NASA’s Launch Services Program completed a “crossover assessment” review over the weekend to determine if there might be shared hardware or other links between the Falcon 9 and the Atlas 5. “There is no elevated risk to OSIRIS-REx launching on an Atlas 5,” he said.

Scott Messer, program manager for NASA missions at ULA, said workers did an extensive search of the pad at Space Launch Complex 41 and the assembly building that contains the rocket and spacecraft, and found no damage or debris there linked to the Falcon 9 explosion. “At this point, we haven’t identified any risks, and we’re on track for launch on the 8th,” he said.

OSIRIS-REx, the third mission in NASA’s New Frontiers line of medium-sized planetary science missions, will travel to the near Earth asteroid Bennu, arriving in August 2018. The spacecraft will study the asteroid with cameras and other instruments for nearly two years.

The key moment for the mission will come in mid-2020, when the spacecraft attempts to collect samples of the asteroid’s regolith, the layer of pulverized rock on its surface. The spacecraft will slowly approach Bennu, extending a sampling tool called the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) at the end of a robotic arm. TAGSAM will briefly make contact with the surface, firing puffs of nitrogen gas that will move regolith into the collection tool.

TAGSAM will spend only a few seconds on the surface of the asteroid before moving away. “We’ll do a safe, slow, smooth high-five to collect that sample,” said Christina Richey, OSIRIS-REx deputy program scientist at NASA Headquarters. The goal is to collect at least 60 grams of asteroid samples, but project officials said they believe they can collect several times that amount based on laboratory tests of TAGSAM.

After placing the sample in a return canister based on the one used on the Stardust comet sampling mission, OSIRIS-REx will leave Bennu in March 2021, returning to Earth in September 2023. The main spacecraft will fly past Earth while the sample return canister parachutes to a landing in Utah.

Dante Lauretta of the University of Arizona, the principal investigator for OSIRIS-REx, said at the briefing he was looking forward to the launch. “I’m absolutely not nervous because we have a phenomenal team and they know what they’re doing,” he said. “I am anxious, because I’ve been working on this program for 12 years now, and I really want to fly this spacecraft.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...