This maneuver marks the beginning of the next phase of the spacecraft’s mission, called Orbital B. The mission brings the probe to a distance of 2,231 feet above the asteroid’s surface, making it closer than ever to the asteroid Bennu. The previous record measured 0.8 miles above its surface.
When the spacecraft arrived at the asteroid, the team needed to learn about its movement so it could safely fit the spacecraft in. Team members observed particles that are ejected into space from the asteroid’s surface, so the beginning of the Orbital B phase was devoted to understanding those events by taking photos of the asteroid’s horizon.
Now that OSIRUS-REx is closer than ever to the asteroid Bennu, it will map the entire asteroid using its instruments, such as the OSIRIS-REx Laser Altimeter (OLA,) PolyCam, the OSIRIS-REx Thermal Emission Spectrometer, and the Regolith X-ray Imaging Spectrometer (REXIS).
The spacecraft is expected to stay in Orbital B until the second week of August, when it will move to the Orbital C position to observe other particles. At that time, the spacecraft will be orbiting 0.8 miles above the asteroid’s surface.
The team will use the data collected during the Orbital B phase to learn more about the safety and probability of extracting a sample of the asteroid’s surface safely. Based on that data, the team will pick four sample sites to be examined before the spacecraft attempts to send the sample back. This will take place during the fall as part of the reconnaissance phase of the mission.
The OSIRIS-REx team will have to consider a few more safety requirements before they prepare for the sample collection. The site must be clear of large rocks and boulders so that the spacecraft can have an easier time navigating without encountering obstacles that could lead to damage. Moreover, the site must not be tilted too much as opposed to the sampling arm, especially given the rocky surface of Bennu.
The end of the OSIRIS-REx’s mission is nowhere near, and it will get even closer to the asteroid Bennu by eventually landing on it. The mission will last seven years, and once it returns the sample to Earth, scientists will be able to analyze it and hopefully gain new insights of the formation of the solar system, which they believe occurred over 4.5 billion years ago. The sample collection will likely take place in 2020, while it is expected to be delivered by September 2023.