KENNEDY SPACE CENTER, Fla. — A spacecraft that will fly NASA’s first asteroid sample return mission arrived in Florida May 20 to begin final preparations for its September launch.

A U.S. Air Force C-17 cargo aircraft landed at the Shuttle Landing Facility here at 7:20 p.m. Eastern, delivering the Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer (OSIRIS-REx) spacecraft. The C-17 arrived from Buckley Air Force Base in Colorado, near the Lockheed Martin facility where the spacecraft was assembled.

The transport of the spacecraft from Colorado to Florida went as planned, much to the relief of the mission’s principal investigator, Dante Lauretta of the University of Arizona. “Everything’s going according to plan,” he said after arrival here.

OSIRIS-REx now enters final preparations for launch on a United Launch Alliance Atlas 5, currently scheduled for Sept. 8 from Cape Canaveral at the beginning of a launch window that lasts a little more than one month. Immediately after landing, the spacecraft was transported to the Payload Hazardous Servicing Facility here to begin that work.

The spacecraft will rendezvous with the near Earth asteroid Bennu in August 2018. OSIRIS-REx will study the asteroid with a suite of instruments including cameras, spectrometers and a laser altimeter.

OSIRIS-REx will also deploy a robotic arm to collect at least 60 grams of asteroid samples. The spacecraft will depart Bennu in March 2021 and return the samples to Earth in September 2023.

OSIRIS-REx will be NASA’s first mission to return samples from the asteroid, but not the first mission overall. Japan’s Hayabusa spacecraft collected samples from the asteroid Itokawa in 2005 and returned them to Earth in 2010. Hayabusa 2, a follow-up mission launched in December 2014, will collect samples from the asteroid Ryugu and return them to Earth in 2020.

OSIRIS-REx is the third in NASA’s New Frontiers series of medium-class planetary science missions. The first, New Horizons, flew past Pluto in July 2015. Juno, the second New Frontiers mission, will enter orbit around Jupiter on July 4.

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...