It's the first spacecraft to orbit such a small object, but it won't be the first to make contact: Japan brought back an asteroid sample in 2010.
The spacecraft, technically the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) is orbiting the asteroid Bennu, a diamond-shaped chunk of space rock with a varying orbit that keeps it around 100 million miles (160 million kilometers) from Earth. The special broadcast will begin at 11:45 a.m.in case the space probe arrives early to 12:15 p.m. EST. During this period, OSIRIS-REx completed four maneuvers slowing the spacecraft's velocity from approximately 1,100 miles per hour (491 m/sec) to 0.10 miles per hour (0.04 m/sec) relative to Bennu, which resulted in the slower approach speed at the end of the video.
The goal of both missions is to learn more about how the original solar nebula coalesced to form the sun and its retinue of planets, asteroids and comets, giving scientists a better understanding of the raw materials that went into Earth's construction and even the eventual development of life.
After today, OSIRIS-REx will spend almost a year examining Bennu and sending back highly detailed images of its surface.
The Touch-and-Go Sample Acquisition Mechanism (TAGSAM) will suck up the regolith, kicked up by its nitrogen gas thrusters, and hopefully collect enough to study back at home. However, the space probe's main mission will not begin until next year. Its proximity to us made it a prime target for OSIRIS-REx.More news: UP CM, DGP say Bulandshahr incident ‘part of larger conspiracy’
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Over the next four weeks, the spacecraft will conduct multiple flybys of Bennu, collecting data to help scientists determine the asteroid's mass.
Finally, on September 24, 2023, a capsule containing the sample will streak through Earth's atmosphere and land in the Utah desert. For 27 months, the craft has been traveling through the solar system en route to Bennu, which orbits the Sun between Earth and Mars.
Achievement unlocked: "We have arrived!" For example, the probe's measurements, and those of researchers studying the returned sample, should reveal a great deal about the resource potential of Bennu-like asteroids. The rapid rotation also sends small rocks on the asteroid's surface flying into space, meaning there's nothing there for the spacecraft to collect. Bennu's nearly 500 meters in diameter, and rotates only once every 4.3 hours. The second sequence shows the spacecraft's fly-in approach with Bennu slowly growing larger in the distance.
During a survey lasting one and a half years, the explorer will touch down on the surface up to three times to retrieve rocks totaling about 2 kilograms.
This meeting will provide scientists with a rare window to look back at the beginnings of Earth's solar system, said Jay McMahon, an assistant professor in aerospace engineering at CU Boulder.
'Bennu is a leftover fragment from the tumultuous formation of the solar system, ' NASA says.