LOS ANGELES: A Nasa space capsule carrying a sample of rocky material plucked from the surface of an asteroid three years ago hurtled towards Earth this weekend headed for a fiery plunge through the atmosphere and a parachute landing in the Utah desert on Sunday.

Weather forecasts were favourable and the robotic spacecraft OSIRIS-REx was on course to release the sample-return capsule for final descent as planned, with no further adjustments to its flight path needed, Nasa officials said at a news briefing on Friday.

Mission managers are expecting a “spot-on” touchdown on the US military’s vast Utah Test and Training range, west of Salt Lake City, said Sandra Freund, programme manager at Lockheed Martin, which designed and built the spacecraft.

The round, gumdrop-shaped capsule is scheduled to land by parachute at 10:55am, about 13 minutes after streaking into the top of the atmosphere at roughly 35 times the speed of sound, capping a seven-year voyage.

If successful, the OSIRIS-REx mission, a joint effort between Nasa and scientists at the University of Arizona, would mark the third asteroid sample, and by far the largest, ever returned to Earth for analysis, following two similar missions by Japan’s space agency over the past 13 years.

OSIRIS-REx collected its specimen from Bennu, a carbon-rich asteroid discovered in 1999 and classified as a “near-Earth object” because it passes relatively close to our planet every six years.

Bennu is small as asteroids go, measuring just 1,600 feet in diameter.

It holds valuable clues to the origins and development of rocky planets such as Earth.

OSIRIS-REx launched in September 2016 and reached Bennu in 2018, then spent nearly two years orbiting the asteroid before venturing close enough to sink its robot arm into the loose surface on Oct 20, 2020, in a grab-and-go maneuver.

The spacecraft embark­­ed on a 1.2-billion-mile cruise back to Earth in May 2021.

The Bennu sample is estimated at 250 grams, far surpassing the amount of material carried back from asteroid Ryugu in 2020 and asteroid Itokawa in 2010.

On arrival, the new sample will be flown by helicopter to a “clean room” set up at the Utah test range.

Published in Dawn, September 24rd, 2023