OSIRIS-REx completes New Year's Eve orbit insertion burn at asteroid
After four weeks of navigating in the vicinity of asteroid Bennu, NASA's OSIRIS-REx spacecraft fired its thrusters for eight seconds Monday to slip into orbit around the carbon-rich object, making Bennu the smallest planetary body ever orbited by a spacecraft.
OSIRIS-REx arrived at Bennu on Dec. 3, ending a journey from Earth that lasted more than two years and spanned 1.2 billion miles (2 billion kilometers). Since then, the robotic spacecraft has surveyed the 1,600-foot-wide (492-meter) asteroid through a series of flybys as close as 4.4 miles (7 kilometers) over Bennu's north pole, south pole and equator to measure the asteroid's gravitational tug on OSIRIS-REx, which helped scientists determine the object's mass.
The mass estimate helped navigators refine the parameters of OSIRIS-REx's maneuver to enter orbit around Bennu. The craft's thrusters ignited for 8 seconds at 2:43:55 p.m. EST (1943:55 GMT) Monday to slightly adjust OSIRIS-REx's velocity, nudging it just enough for Bennu's tenuous gravity to capture the probe into orbit.
[...] During the mission's first orbital phase, OSIRIS-REx is orbiting the asteroid at a range of 0.9 miles (1.4 km) to 1.24 miles (2.0 km) from the center of Bennu, setting another record for the closest distance any spacecraft has orbited to a planetary body.
Also at The Guardian.
Previously: NASA's OSIRIS-REx "Arrives" at Asteroid Bennu
NASA Finds Evidence of Water on Asteroid Bennu
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NASA's Osiris-Rex Arriving at Asteroid Bennu After a Two-Year Journey
Launched two years ago, NASA's Osiris-Rex spacecraft arrives at the asteroid Bennu on Monday. Its mission is to survey the asteroid ahead of retrieving pristine bits of the solar system from the rock's surface and then bringing them back to Earth in the years ahead.
[...] Osiris-Rex is pulling in at a modest speed, and the moment of arrival is a somewhat arbitrary designation. The spacecraft started the approach phase of its mission in August when it was 1.2 million miles from Bennu. On Monday, it will be 12 miles away, although still too far away to orbit the asteroid. There should be no drama. It should be just a smooth transition to the next phase of the mission.
Osiris-Rex will make a series of passes over the asteroid at a range of 4.3 miles for an initial survey to better determine its mass, rate of spin and shape. In January, the spacecraft will get closer to Bennu, between 0.9 and 1.2 miles, and be drawn into orbit around the asteroid. It will then spend more than a year performing reconnaissance of Bennu before attempting to bounce off the surface and collect a sample of the asteroid in mid-2020.
OSIRIS-REx and 101955 Bennu.
Previously: New Horizons Spacecraft Approaches 2014 MU69; OSIRIS-REx Nears 101955 Bennu
OSIRIS-REx Approaches Bennu, Sends Photo Captured at a Distance of 330 km
The OSIRIS-REx spacecraft, which "arrived" at the asteroid Bennu on December 3 but has been slowly approaching it for weeks, has found evidence of Bennu's interaction with liquid water in the past:
In a conference today, scientists announced that OSIRIS-REx has found evidence of hydrated minerals on the surface of Bennu using its on-board spectrometers - tools used to determine the exact chemical composition of a specific spot.
That means "evidence of liquid water" in Bennu's past, according to Amy Simon, the scientist overseeing OSIRIS-REx's spectral analysis.
"To get hydrated minerals in the first place, to get clays, you have to have water interacting with regular minerals," says Simon. "This is a great surprise."
And they're abundant, too. There's "strong convincing, evidence that the surface is dominated by these hydrated minerals," according to Dante Lauretta, leader of OSIRIS-REx's sample return mission, leading the team to believe Bennu is "water rich".
NASA reports, via NASA, that OSIRIS-REx is leaving Bennu.
NASA's OSIRIS-REx completed its last flyover of Bennu around 6 a.m. EDT (4 a.m. MDT) April 7 and is now slowly drifting away from the asteroid; however, the mission team will have to wait a few more days to find out how the spacecraft changed the surface of Bennu when it grabbed a sample of the asteroid.
The OSIRIS-REx team added this flyby to document surface changes resulting from the Touch and Go (TAG) sample collection maneuver Oct. 20, 2020. "By surveying the distribution of the excavated material around the TAG site, we will learn more about the nature of the surface and subsurface materials along with the mechanical properties of the asteroid," said Dr. Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona.
During the flyby, OSIRIS-REx imaged Bennu for 5.9 hours, covering more than a full rotation of the asteroid. It flew within 2.1 miles' (3.5 kilometers) distance to the surface of Bennu – the closest it's been since the TAG sample collection event.
Just to mention, the survey and selection of a sampling site was one of the recent "citizen science" projects.
(Score: 0) by Anonymous Coward on Wednesday January 02 2019, @04:52PM
I've achieved much lower orbits in KSP.