Recently, National Aeronautics and Space Administration (NASA)’s OSIRIS-REx spacecraft began its two-year journey back to Earth from asteroid Bennu. Marking NASA’s first mission to visit a near-Earth asteroid, survey it, and collect a sample, the spacecraft brings the promise of the largest amount of extraterrestrial material to be returned to Earth since the Apollo era. Launched in 2016, the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission is a trajectory spanning seven years, which will conclude once a minimum of 60 grams of samples are delivered back to Earth in 2023.
What’s on Board?
The spacecraft comes with five instruments meant to help explore Bennu. These include cameras, a spectrometer, and a laser altimeter. The robotic arm of the spacecraft, famously known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), was used to “TAG” the asteroid at a sample site and gather a sample.
The Promise of Asteroid Bennu
Bennu, an ancient asteroid more than 200 million miles from Earth, is approximately as tall as the Empire State Building. It was discovered by the NASA-funded Lincoln Near-Earth Asteroid Research team in 1999. Identified as a B-type asteroid, Bennu contains significant amounts of carbon and various other minerals. Only reflecting about 4% of the light that hits it due to its high carbon content, this figure is notably low in comparison to Venus which reflects 65% and Earth which reflects about 30% of the light.
The Origin and Future of Bennu
The interior of Bennu holds about 20-40% of empty space. Scientists believe that Bennu formed in the initial 10 million years of the solar system’s formation, making it approximately 4.5 billion years old. As a Near Earth Object (NEO), there is a slight chance that Bennu might collide with Earth between the years 2175 and 2199.
The Scientific Significance of Asteroid Samples
Researchers will use the asteroid samples to study the formation of the solar system and habitable planets such as Earth. NASA plans to distribute part of the samples to laboratories across the world, and will reserve about 75% of the samples for future generations who can study it with technologies not yet created.
Introducing Asteroids: The Minor Planets
Asteroids are rocky objects that orbit the Sun and are much smaller than planets. NASA’s current tally of known asteroids stands at 994,383. These remnants from the formation of the solar system over 4.6 billion years ago are sorted into three classes. Those found in the main asteroid belt between Mars and Jupiter, estimated to contain between 1.1-1.9 million asteroids make the first class. The second group constitutes of trojans, which share an orbit with a larger planet. The third classification includes Near-Earth Asteroids (NEA), with orbits that pass close by the Earth. Over 1,400 of these, classified as Potentially Hazardous Asteroids (PHAs), cross Earth’s orbit and possess the potential to make threateningly close approaches to our planet.
