NASA’s OSIRIS-REx spacecraft moved inside about 131 ft, or 40 meters, of asteroid Bennu this 7 days in the $1 billion mission’s remaining practice operate prior to a contact-and-go landing on the asteroid in Oct to obtain samples for return to Earth.
All through the sampling rehearsal Tuesday, engineers monitoring the spacecraft’s maneuvers from Earth confirmed that navigation algorithms, software for autonomous functions, science devices, and quite a few mechanical systems all functioned as predicted.
On Tuesday, the OSIRIS-REx spacecraft fired thrusters to go away a “safe-household orbit” roughly .6 miles (1 kilometer) from asteroid Bennu, then descended to a issue all-around 410 toes (125 meters) higher than the asteroid’s area. The spacecraft then fired thrusters to execute a so-termed “checkpoint” burn off to start out a absolutely free tumble towards the asteroid.
Eight minutes later, OSIRIS-REx pulsed its handle jets again for a “matchpoint” burn up to match the spacecraft’s motion with the asteroid’s rotation. That permits the spacecraft to make its remaining descent to the area more than the specific sampling area.
The spacecraft continued descending toward the asteroid for 3 minutes following the matchpoint melt away, achieving a stage 131 feet from Bennu ahead of firing thrusters yet again for a back again-absent maneuver.
The place OSIRIS-REx attained all through Tuesday’s rehearsal marked the closest the spacecraft has appear to asteroid Bennu, next a similar sampling workout in April that practiced the mission’s descent maneuvers up to a position 213 ft, or 65 meters, from the asteroid.
Following launching from Earth in 2016 and arriving at its asteroid goal in 2018, NASA’s Origins, Spectral Interpretation, Source Identification, Protection, Regolith Explorer, or OSIRIS-REx, spacecraft has been mapping Bennu with cameras, mineral-sniffing spectrometers and a Canadian-constructed laser to measure its roughness.
Shaped like a spinning top rated, Bennu measures close to 1,614 toes (492 meters) large. At the time of Tuesday’s rehearsal, the asteroid was found about 179 million miles (288 million kilometers) from Earth. At that length, it requires 16 minutes for commands from floor teams to achieve the OSIRIS-REx spacecraft.
“This time lag prevented reside commanding of flight activities from the floor throughout the rehearsal,” NASA said in a assertion. “As a consequence, the spacecraft performed the total rehearsal sequence autonomously.”
Ground controllers uplinked the descent sequence to the spacecraft forward of time, and OSIRIS-REx flew the descent profile on autopilot, just as it will on the real sampling endeavor.
OSIRIS-REx has been scouting sites for its sample selection operate, but researchers discovered Bennu is extra rugged than anticipated.
The spacecraft’s sampling rehearsal Tuesday specific a place dubbed Nightingale, the mission’s major sample collection internet site found within a 460-foot (140-meter) crater in Bennu’s northern hemisphere. The web site is surrounded by boulders and sharp terrain, and that compelled engineers to develop upgraded navigation abilities to allow for the spacecraft to guidebook itself to a safe and sound touch-and-go landing.
OSIRIS-REx takes advantage of a functionality named normal attribute monitoring to get a series of photographs with a navigation digital camera to autonomously recognize rocks, craters and other markings on the asteroid’s surface, yielding knowledge on situation and relative velocity. The spacecraft’s laptop compares the imagery with a map of dangers loaded into the laptop or computer ahead of the descent. If OSIRIS-REx detects it is approaching a harmful area, it can command an abort and back absent from Bennu.
The natural element monitoring algorithms were being efficiently tested all through Tuesday’s rehearsal. The spacecraft’s cameras captured greater-resolution views of the Nightingale sampling spot when OSIRIS-REx was flying instantly more than the internet site, allowing for floor groups to update and refine the natural aspect monitoring capability prior to the actual sampling attempt in October.
“Many crucial systems were exercised through this rehearsal — from communications, spacecraft thrusters, and most importantly, the on-board natural attribute monitoring direction method and hazard map,” Dante Lauretta, OSIRIS-REx’s principal investigator from the College of Arizona, Tucson. “Now that we’ve concluded this milestone, we are assured in finalizing the treatments for the TAG (Touch-And-Go) function. This rehearsal verified that the staff and all of the spacecraft’s units are ready to accumulate a sample in Oct.”
OSIRIS-REx also extended its sample assortment arm, regarded as TAGSAM, during Tuesday’s rehearsal. The spacecraft also moved its two solar array wings to a “Y-wing” configuration to safely situation them absent from the asteroid’s surface area, just as they will be positioned throughout the touch-and-go landing.
The TAGSAM arm was later on retracted back again to a stowed placement following OSIRIS-REx started flying away from Bennu at the conclusion of the rehearsal Tuesday.
During the mission’s genuine sampling run, a product mounted on the conclude of the spacecraft’s TAGSAM arm will call the asteroid surface for quite a few seconds and fire compressed nitrogen gas. The gasoline cartridge will disrupt the rock at the sampling internet site, and the spacecraft will capture some of the product in a chamber for return to Earth.
Experts hope to gather at minimum 2.1 ounces (60 grams) of pristine samples from Bennu’s area, and return the materials to Earth in September 2023 for evaluation in advanced laboratories. Researchers will look at the specimens to search for signals of organic and natural make a difference and other chemicals vital to the origin of existence.
Built and operated by Lockheed Martin, the OSIRIS-REx spacecraft launched from Cape Canaveral in September 2016. A constrained number of staff managed Tuesday’s checkpoint rehearsal from a Lockheed Martin handle middle in Colorado, furthermore sites at the Goddard House Flight Middle in Maryland and the College of Arizona.
Other group members participated remotely thanks to the coronavirus pandemic, NASA reported.
Before this year, mission administrators resolved to give groups far more time to get ready for OSIRIS-REx’s sampling try as officials adjusted to new operations techniques to minimize dangers from COVID-19.
That conclusion delayed OSIRIS-REx’s second sampling rehearsal from June 23 to Aug. 11, and pushed again the actual sampling run from Aug. 25 to Oct. 20.
If the very first sampling try turns up vacant in Oct, scientists have penciled in chances for more attempts ahead of the spacecraft departs Bennu next year to begin the return vacation to Earth.
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