NASA spacecraft OSIRIS-REx is currently gearing up to begin its sample return mission. Recently, scientists on the mission presented new findings on asteroid Bennu’s surface material, geological characteristics, and dynamic history. Researchers have noted they suspect the sample delivered back to earth from the asteroid could be unlike anything we have in the meteorite collection on Earth.
The discoveries the scientists are talking about have completed the mission pre-sample collection science requirements and provide insights into the asteroid that will be studied for generations to come. One paper led by Amy Simon from the Goddard Space Flight Center showed carbon-bearing, organic material is widespread on the asteroid’s surface, including the primary mission landing site. The landing site is where OSIRIS-REx will perform its first sample collection attempt on October 20. Findings from that study show that hydrated minerals and organic material are expected to be present at the landing site. Researchers hope the study of the organic molecules could help answer questions about the origins of water and life on Earth.
Scientists are optimistic that the abundance of carbon-bearing material means the spacecraft will sample that material and return it to Earth. The team also found that many boulders and rocks on the surface of the asteroid have bright veins in them that appear to be carbonate. Some of those rocks are located near Nightingale crater, indicating there is a chance carbonates could be present in the returned samples.
The presence of carbonates leads the team to believe that the parent asteroid of Bennu likely had an extensive hydrothermal system where water interacted with and altered the rock on the parent body. The veins in some of the boulders on the asteroid are up to a few feet long and several inches thick, which scientists say validates and asteroid-scale hydrothermal system of water on the parent body.
Science teams also found the regolith at the Nightingale landing site has only been exposed to the harsh space environment. That means that Bennu will collect and return some of the most pristine material on the asteroid. Another of the papers distinguished two main types of boulders on the asteroid’s surface – dark and rough and bright and smooth. They believe the two different types of rock may have formed at different depths of the parent asteroid. The dark and rough porous rock would be destroyed on entry to the Earth’s atmosphere and may have never been seen in samples collected on Earth.