NASA's Osiris-Rex mission set for a sample grab from asteroid Bennu

[lizkat]

This will be an edge-of-chairs experience for the NASA project teams... the spacecraft has enough nitrogen aboard to take just three shots at obtaining a shallow-depth sample of the asteroid's boulder and rubble-strewn surface material. It's been trained to back away if it spots boulders large enough to endanger the mission's success, and an optimum ("largely boulder-free") place has been selected for an approach for the brief contact. However, a spokesman commented that overall it's been like trying to nail down a parking close to your house from two million miles away. One might add, "oh, and having the barista bring the coffee to the curb."

Touch-and-go: US spacecraft sampling asteroid for return

CAPE CANAVERAL, Fla. (AP) — After almost two years circling an ancient asteroid hundreds of millions of miles away, a NASA spacecraft this week will attempt to descend to the treacherous, boulder-packed surface and snatch a handful of rubble.

apnews.com

Once it drops out of its half-mile-high (0.75 kilometer-high) orbit around Bennu, the spacecraft will take a deliberate four hours to make it all the way down, to just above the surface.

Then the action cranks up when Osiris-Rex’s 11-foot (3.4-meter) arm reaches out and touches Bennu. Contact should last five to 10 seconds, just long enough to shoot out pressurized nitrogen gas and suck up the churned dirt and gravel. Programmed in advance, the spacecraft will operate autonomously during the unprecedented touch-and-go maneuver. With an 18-minute lag in radio communication each way, ground controllers for spacecraft builder Lockheed Martin near Denver can’t intervene.

Well here's hoping. It would be good to know more about Bennu, since it orbits the sun as Earth does, and swings fairly close to us every six years... there's a 1 in 2700 chance of it colliding with planet Earth late in the 21st century. Assuming we're still maintaining a human habitat on Earth by then, we might have to plan on trying to divert Bennu's orbit with a well thought out shove. Wow, trusting that yet another autonomous finale would work well... but we'd probably only have one shot at getting that right.