On board OSIRIS-REx as it flies by Earth are 440,000 names of people who wanted to symbolically join the mission. In partnership with the mission, The Planetary Society collected the names as part of its Messages from Earth program. The collection includes the names of everyone who was a Planetary Society member at the time. One copy of those names is stored aboard the spacecraft's sample return capsule, and will plunge back to Earth in 2023. Another copy, aboard the main spacecraft, will remain in space after the sample return capsule is dropped off. The Planetary Society also helped give the target asteroid for OSIRIS-REx, Bennu, its name by running a contest won by Michael Puzio, who was 9 years old at the time.

No rocket firings are planned for the flyby; the spacecraft will coast through it. Out of an abundance of caution, engineers turned off all of its instruments about a month ago. Assuming the flyby goes according to plan, the instruments will power up about 2 hours after the flyby. Beginning about 4 hours after closest approach, OSIRIS-REx will begin testing cameras and spectrometers on Earth and the Moon. All the cameras as well as two spectrometers will see use in four science observation windows spaced across the 10 days after the flyby; only the laser altimeter and X-ray spectrometer will not get used. In total, OSIRIS-REx will acquire nearly 1000 images.

Data transmission will not happen instantaneously. The data will arrive on the ground 24 to 48 hours after the close of each of the four science observation windows. There is not yet an automated pipeline for sending OSIRIS-REx data to the Web. Assuming everything goes well with the spacecraft through and after the flyby, you can expect to see the first photos on Tuesday, September 26; watch for NASA press releases and also check asteroidmission.org.

Following is a predicted timeline of the coming OSIRIS-REx events. Because the spacecraft is close to Earth, the difference between spacecraft event time and Earth received time is never more than a few seconds throughout the flyby period, so I am only reporting Earth received time here.