NASA’s OSIRIS-REx spacecraft just arrived at Bennu on December 3 (SN Online: 12/3/18). Already, the spacecraft is reporting incredible discoveries.
OSIRIS-REx stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer.
Over the next year, mission scientists will look for the perfect spot on the asteroid to obtain a handful of rock and dirt samples and return it to Earth.
“Very early in the mission, we’ve found out Bennu is going to provide the type of material we want to return,” explained principal investigator Dante Lauretta of the University of Arizona in Tucson.
“It definitely looks like we’ve gone to the right place.”
But even before we get a chance to analyze the surface of Bennu through samples brought back to Earth, we’ve already made a stunning discovery.
OSIRIS-REx has discovered traces of water on Bennu.
OSIRIS-REx’s has 2 spectrometers on board which measure the chemical signatures of a number of different minerals based on the wavelengths of light they emit and eventually absorb.
The instruments detected signs of hydrated minerals on Bennu’s surface a month before the spacecraft entered into orbit around at the asteroid. Most importantly, the signal remained strong all over the asteroid’s surface as the spacecraft approached, Simon explained.
Interestingly. those minerals can form only in the presence of liquid water and tell us that Bennu had a hydrothermal system in its past.
The probe, which launched back in 2016, successfully arrived a mere 12 miles from the 1,600-foot-wide asteroid on December 3rd, carrying an armory of instruments that will be used to explore the asteroid like never before.
As explained in a statement by NASA, “the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) and the OSIRIS-REx Thermal Emission Spectrometer (OTES), reveal the presence of molecules that contain oxygen and hydrogen atoms bonded together, known as hydroxyls.”
“The team suspects that these hydroxyl groups exist globally across the asteroid in water-bearing clay minerals, meaning that at some point, Bennu’s rocky material interacted with water. While Bennu itself is too small to have ever hosted liquid water, the finding does indicate that liquid water was present at some time on Bennu’s parent body, a much larger asteroid.”
“The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” said Simon
“When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”