One year after launch, NASA’s OSIRIS-REx booster is racing behind toward Earth for a vicious flyby Friday, regulating a planet’s sobriety to change march and set adult a event with a asteroid Bennu late subsequent year in a billion-dollar idea to squeeze a representation from a aspect and lapse it to watchful scientists.
Streaking by space during some 19,000 miles per hour, OSIRIS-REx will make a closest proceed to Earth during 12:52 p.m. ET Friday, flitting some 11,000 miles above Antarctica only south of Cape Horn, Chile, in a long-planned gravity-assist flyby that will boost a probe’s quickness and, some-more important, put it in a same orbital craft as Bennu.
“It’s mostly a change in direction,” Mike Moreau, a moody dynamics lead during NASA’s Goddard Space Flight Center, pronounced in an interview. “Flying underneath a stick kind of tips us adult and out of a Earth [orbital] craft and gets us aligned to Bennu’s plane. It’s about a six-degree difference.”
The Earth flyby also will give OSIRIS-REx a indispensable quickness boost. The sum change in quickness after a flyby is about 8,400 miles per hour. To put that in perspective, a many a booster could do on a own, regulating a whole bucket of propellant, would be about 4,250 mph.
“So a distance of this maneuver, if we will, is most incomparable than a sum propulsive capability of a vehicle,” Moreau said. “That’s because we use a Earth flyby. It opens adult arena options that would not be accessible only with a fuel we lift on board.”
Four hours after tighten approach, OSIRIS-REx will start a array of observations of a Earth and moon to assistance engineers regulate a instruments as it starts a final leg of a two-year excursion to Bennu, nearing in Oct 2018 or shortly thereafter.
The booster will spend dual years mapping a tiny asteroid in unusual detail, regulating a worldly camera, dual vegetable sniffing spectrometers, a laser altimeter and a student-managed X-ray imaging complement before unlimbering a drudge arm in Jul 2020 to collect a dirt representation from a surface.
The idea is to constraint during slightest 2.1 ounces of element and, depending on a inlet of a surface, adult to 4.4 pounds.
With a collected element safely stowed in a re-entry capsule, OSIRIS-REx will bid Bennu farewell in Mar 2021, environment off on a two-year excursion behind to Earth. The 100-pound representation plug will be expelled in Sep 2023, attack Earth’s atmosphere during a peppery 27,000 mph before a peaceful parachute-assisted touchdown in Utah.
Appropriately enough, a spacecraft’s name is a involved acronym station for Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer.
Moreau credited a group of engineers during KinetX Aerospace for a accurate navigation that is running OSIRIS-REx to a target.
“The KinetX guys have this down, a low space navigation partial of it,” he said. “Right now, only in a final few days as we’ve been coming [Earth], a doubt in a position is reduction than a kilometer and a few tenths of a second during a time of closest approach.”
He pronounced a flyby “is cool, though many people don’t comprehend OSIRIS-REx is an intensely severe idea from a navigation perspective.”
“When we arrive during Bennu, it’s one of a smallest objects that’s ever been visited, and we’re going into these unequivocally tight, tiny orbits around it where we’ll be as tighten as 700 meters from a surface,” he said. “The hurdles of doing that are unequivocally extreme, we have to indication all of these unequivocally tiny army on a booster intensely precisely.”
The vigour of object on a spacecraft, for example, can means unequivocally slight changes that have to be taken into account, along with pointed thermal effects.
“When a booster slews and there’s a prohibited aspect that was unprotected to a object and now it’s in shadow, that radiates heat, and that creates a tiny acceleration,” Moreau said. “We have models for all that stuff. we consider we could substantially contend we’ve characterized OSIRIS-REx during this indicate improved than roughly any heavenly mission.”
As for a Earth flyby Friday, a navigation group will guard a spacecraft’s arena “just to make certain all is on track,” Moreau said. At a same time, booster engineers will guard telemetry to make certain a scholarship instruments are prepared for a designed Earth-moon calibration observations.
And while OSIRIS-REx will fly by a segment of near-Earth space during a flyby that is populated by a accumulation of satellites, a contingency of a collision are intensely low. Moreau pronounced a minute research showed a half-dozen satellites could be within 600 miles of so of a booster during one indicate or another, “but there was unequivocally never a poignant possibility of carrying a and with anything.”