OSIRIS-Rex – Atlas V 411 (AV-067) – Canaveral SLC-41 – 08.09.2016 23:05 UTC

Автор Anatoly Zak, 26.05.2011 08:53:55

« назад - далее »

0 Пользователи и 1 гость просматривают эту тему.

instml

Пролет Земли 23 сентября 2017 над Антарктидой на высоте около 17 тыс. км.

Кампания по наблюдению Земли и Луны 22 сент - 7 окт 2017
Go MSL!


Salo

https://ria.ru/science/20170118/1485974321.html
ЦитироватьЗонд НАСА совершил первый маневр на пути к "астероиду апокалипсиса"
17:03 18.01.2017

© NASA/ NASA's Goddard Space Flight Center/Conceptual Image Lab

МОСКВА, 18 янв – РИА Новости. Зонд OSIRIS-REx успешно совершил первый маневр в глубоком космосе, который вывел его на траекторию сближения с Землей для дальнейшего разгона на пути к астероиду-"убийце" Бенну, сообщает НАСА.
"Маневр DSM-1 важен по той причине, что мы впервые сильно изменили траекторию полета зонда и впервые включили его главный двигатель. Приятно, что этот важный этап в нашем путешествии к Бенну успешно завершился, и мы продолжаем полет к астероиду", — заявила Арлин Бартельс (Arlin Bartels) из Центра космических полетов имени Годдарда.
Зонд OSIRIS-REx успешно вывели на околоземную орбиту в минувшем сентябре. Цель миссии – сближение и забор грунта с поверхности астероида Бенну (1999 RQ36). По текущим планам НАСА, зонд сблизится с астероидом в 2018 году, заберет грунт в 2019 году и запустит капсулу как минимум с 60 граммами астероидной материи в направлении Земли. Приземлиться она должна на территории штата Юта в конце сентября 2023 года.
OSIRIS-REx для экономии топлива будет лететь к Бенну не по прямой траектории, а совершит "турне" по окрестностям Земли, почти вернувшись назад предстоящей осенью. Совершив "петлю", зонд пролетит на расстоянии 20 тысяч километров от поверхности планеты, чтобы использовать силу ее притяжения для разгона и выхода на траекторию сближения с астероидом.
По такому же принципу действует праща, разгоняя и выпуская камень.
Первый орбитальный маневр, или DSM-1, был проведен в канун Нового года, 28 декабря, после чего скорость зонда выросла на полторы тысячи километров в час. Ради этого аппарат сжег 350 килограммов топлива. Данные об успешном завершении маневра были переданы на Землю только недавно. Теперь НАСА планирует провести еще одну небольшую коррекцию орбиты для максимально тесного сближения зонда с Землей во время гравитационного разгона.
Ближайшие два года полета к Бенну зонд не проведет впустую. Уже в феврале он включит свои камеры и часть научных инструментов для поиска так называемых "троянских" астероидов – квазиспутников Земли, движущихся по ее орбите чуть впереди или чуть позади планеты в тех точках, где гравитация Солнца и Земли уравновешивается. Кроме того, ученые и инженеры миссии будут отрабатывать сценарии сближения OSIRIS-REx с астероидом и поиска оптимальной точки для забора грунта с его поверхности.
Астероид Бенну (Bennu) диаметром около 500 метров открыли в 2013 году. Согласно ряду расчетов, он может столкнуться с Землей в 2169 или 2199 году.
"Были когда-то и мы рысаками!!!"

Salo

http://spaceflightnow.com/2017/02/01/nasas-osiris-rex-probe-moonlights-as-asteroid-sleuth/
ЦитироватьNASA's OSIRIS-REx probe moonlights as asteroid sleuth             
 February 1, 2017 Stephen Clark
 
The OSIRIS-REx spacecraft will undertake a search for Earth-Trojan asteroids while on its outbound journey to the asteroid Bennu. Earth Trojans are asteroids that share an orbit with Earth while remaining near a stable point 60 degrees in front of or behind the planet. Credit: University of Arizona/Heather Roper

On course to collect specimens fr om asteroid Bennu after its launch last year, NASA's OSIRIS-REx spacecraft will search this month for objects sharing an orbit with Earth, a bonus science opportunity to locate possible fragments of the primordial building blocks that formed our home planet.
The long-range observations begin Feb. 9 and run through Feb. 20, using one of the probe's cameras to look for asteroids embedded in swarms scientists believe lurk ahead of and behind Earth in its orbit around the sun.
Named Earth-Trojans, the objects likely group in clouds at Sun-Earth Lagrange points, where the combined pull of gravity fr om the bodies would allow asteroids to orbit in lock-step with Earth. The so-called L4 and L5 Lagrange points lead and follow Earth by 60 degrees in its path around the sun.
The same positions in front of and behind Jupiter harbor thousands of Trojan asteroids, and smaller Trojan swarms have been discovered near Venus, Mars, Uranus and Neptune.
It turns out OSIRIS-REx is about to pass through the Sun-Earth L4 Lagrange point, and managers decided to scan the region where Earth-Trojans might be located to see what the spacecraft can find.
Now located nearly 74 million miles (119 million kilometers) from Earth, OSIRIS-REx is on a seven year-journey to asteroid Bennu and back, charged with gathering rock samples from the mountain-sized object and delivering them to scientists for examination inside laboratories on the ground.
Since its launch Sept. 8, 2016, OSIRIS-REx has switched on all of its science instruments and performed a major course correction maneuver to aim for a flyby of Earth this Sept. 22. Earth's gravity will slingshot the spacecraft toward Bennu.
The Dec. 28 burn changed OSIRIS-REx's speed by 964 mph (431 meters per second) and consumed a quarter of the probe's propellant supply. The maneuver was the largest of the mission until the Lockheed Martin-built spacecraft's arrival burn at Bennu in August 2018.
 
Artist's concept of the OSIRIS-REx spacecraft's deep space maneuver. Credit: NASA

Спойлер
Another small "clean-up" thruster firing Jan. 18 further tweaked OSIRIS-REx's trajectory, and the spacecraft switched over to its high-power antenna Jan. 25 to beam data back to Earth at faster rates.
The milestones clear the way for the mission's first science campaign next week.
"The Earth-Trojan asteroid search provides a substantial advantage to the OSIRIS-REx mission," said Dante Lauretta, OSIRIS-REx principal investigator from the University of Arizona in Tucson. "Not only do we have the opportunity to discover new members of an asteroid class, but more importantly, we are practicing critical mission operations in advance of our arrival at Bennu, which ultimately reduces mission risk."
Only one of the elusive Earth-Trojans has been detected to date.
Astronomers using NASA's WISE infrared telescope confirmed the discovery of an asteroid in 2011 that fit the definition of an Earth-Trojan. Asteroid 2010 TK7 is about 1,000 feet (300 meters) in diameter, and experts predict its extreme orbit, which takes it far above and below the plane of the planets, will be stable for at least the next several thousand years.
Scientists consider 2010 TK7 an outlier of a large group of asteroids sharing Earth's orbit, some of which may have been there since the solar system formed more than 4.5 billion years ago.
"The orbital motion of 2010 TK7 is chaotic and unstable on billion-year timescales, and it is unlikely to be a remnant from the formation of the Earth," Lauretta wrote in a blog post describing the upcoming observing campaign. "The existence and size of a primordial population of Earth-Trojans (genuine remnants of the building blocks of our planet) are not well constrained and represents a significant gap in our inventory of small bodies in near-Earth space."
Earth-Trojans are difficult to find from the ground because they are usually in daylight, and the WISE spacecraft orbiting Earth detected 2010 TK7 because its unique orbit oscillates farther from the sun's position in the sky than most members of the group.
Current ground-based surveys are only sensitive to Earth-Trojan asteroids bigger than about 3,000 feet, or approximately 1 kilometer, said Carl Hergenrother, an OSIRIS-REx staff scientist at the University of Arizona.
 
This artist's concept illustrates the first known Earth-Trojan asteroid, discovered by NEOWISE, the asteroid-hunting portion of NASA's WISE mission. The asteroid is shown in gray and its extreme orbit is shown in green. Earth's orbit around the sun is indicated by blue dots. The objects are not drawn to scale. Credit: Paul Wiegert, University of Western Ontario, Canada

By mid-February, OSIRIS-REx will be "an ideal spot to undertake a survey," Lauretta wrote.
Between Feb. 9 and Feb. 20, the spacecraft's mapping camera will take 145 pictures per day of the volume of space wh ere Earth-Trojans are expected to reside, according to Lauretta.
"It's a big cloud, and there should be material there," Hergenrother said at a Jan. 12 meeting of NASA's Small Bodies Assessment Group. "We should be able to detect stuff down to 100 meters (330 feet), and possibly even smaller, depending on the performance of our cameas, and the albedo (reflectivity).
"If we don't find anything, it either means there's a lot less objects out there than we were thinking, or they're a lot smaller," Hergenrother said.
While Lauretta said there is a scientific motivation for the Earth-Trojan search, the top reason for the campaign is to practice techniques the OSIRIS-REx science team plans to employ once the spacecraft arrives at Bennu.
On approach to Bennu, the probe's cameras will look near the asteroid to hunt for tiny miniature moons as small as 4 inches (10 centimeters). Navigators want to know the location of any debris around Bennu to prevent a crash with the spacecraft.
Jupiter and several large distant asteroids will be imaged by OSIRIS-REx's camera when it scans for Earth-Trojans. The images will help the ground team rehearse the complex real-time in-space navigation the mission requires during the rendezvous with Bennu, along with the identification of moving targets mimicking the behavior of potential mini-moons surrounding the asteroid.
Although the scientific objectives are secondary, Lauretta said his team is excited about the prospect of making a discovery so early in the mission.
"We'll clearly be able to set an upper lim it on what's out there because we know what we could detect if it was there," Lauretta said at the Jan. 12 science meeting.
OSIRIS-REx could also discover an asteroid from another family that just happens to pass through the camera's field-of-view, Lauretta said. But scientists will pin down the orbit of any object OSIRIS-REx detects, and an Earth-Trojan asteroid locked in a stable orbit could be evidence of a larger cloud of mini-worlds hidden from view.
"Is this dynamically stable? Could it be a primordial Earth object?" Lauretta asked, posing questions scientists will have if OSIRIS-REx finds anything starting next week. "That would be the most fascinating thing that we could discover."
[свернуть]
"Были когда-то и мы рысаками!!!"

che wi

Цитировать OSIRIS-REx · Apr 4

At my current distance, it takes just under 7 minutes for me to talk to Earth

che wi

ЦитироватьNASA's OSIRIS-REx@OSIRISREx · 35 minutes ago

Only 100 days until my #EarthGravityAssist -- when I'll borrow some of Earth's orbital energy to slingshot onto Bennu's orbital plane.

Имxотеп

#186
Троянцы Земли не найдены

В феврале OSIRIS-REX прошел через точку L4 системы Солнца-Земля и использовал эту возможность для непосредственного поиска астероидов-троянцев с помощью камеры MapCam. Она может видеть объекты до 14 звездной величины, то есть способна обнаружить астероид размером 200-400 м с расстояния 0.04 а.е. или астероид размером около 100 м с расстояния 0.01 а.е. Для сравнения: земные обзоры PanSTARRS или Catalina могут увидеть в точке L4 астероиды диаметром не менее полукилометра.



Было сделано 1350 снимков 90 полей и найдено 0 троянцев, 17 известных астероидов главного пояса и 1 известная планета (Юпитер).

http://www.lpi.usra.edu/sbag/meetings/jun2017/presentations/Lim.pdf

instml

Пролет Земли через 1 месяц!
Go MSL!

instml

NASA'S ASTEROID SAMPLE RETURN MISSION SUCCESSFULLY ADJUSTS COURSE

August 25, 2017

NASA's OSIRIS-REx spacecraft fired its thrusters to position itself on the correct course for its upcoming Earth flyby. The spacecraft, which is on a two-year outbound journey to asteroid Bennu, successfully performed a precision course adjustment on Wednesday to prepare for the gravity slingshot on Sept. 22.

This trajectory correction maneuver was the first to use the spacecraft's Attitude Control System, or ACS, thrusters in a turn-burn-turn sequence. In this type of sequence, OSIRIS-REx's momentum wheels turn the spacecraft to point the ACS thrusters toward the desired direction for the burn, and the thrusters fire. After the burn, the momentum wheels turn the spacecraft back to its previous orientation. The total thrust is monitored by an on-board accelerometer that will stop the maneuver once the desired thrust is achieved.

High-precision changes in velocity, or speed and direction, will be critical when the OSIRIS-REx spacecraft operates near Bennu. Because Bennu is so small, it has only a weak gravity field. Therefore, it will only require tiny changes in velocity to do many of the maneuvers that are planned to explore and map the asteroid.

The Aug. 23 maneuver began at 1 p.m. EDT and lasted for approximately one minute and 17 seconds. Preliminary tracking data indicate that the maneuver was successful, changing the velocity of the spacecraft by 1.07 miles per hour (47.9 centimeters per second) and using approximately 16 ounces (0.46 kilogram) of fuel.

OSIRIS-REx will fly by Earth on Sept. 22 to use our planet's gravity to propel the spacecraft onto Bennu's orbital plane. As of Friday, Aug. 25, the spacecraft is about 10.3 million miles (16.6 million kilometers) from Earth.

The mission team has another minor Earth-targeting maneuver tentatively planned for Sept. 12. Over the next few weeks, the navigation team will process daily spacecraft tracking data from Wednesday's maneuver to determine whether the additional maneuver is necessary before the Earth gravity assist.

https://www.asteroidmission.org/?latest-news=nasas-asteroid-sample-return-mission-successfully-adjusts-course
Go MSL!

Pirat5

немного больше суток осталось:
Цитировать22.09.2017 o 16:52 w odległości ok. 16000 km od Ziemi przeleci sonda OSIRIS-REx, wykonując manewr grawitacyjny w drodze do planetki (101955) Bennu.
http://lk.astronautilus.pl/plan.htm
16:52 GMT = 19:52 мск


tnt22

ЦитироватьA Slingshot from Earth to Asteroid Bennu
 
NASA Goddard

Опубликовано: 22 сент. 2017 г.

OSIRIS-REx is NASA's mission to explore near-earth asteroid Bennu, collect a sample, and return it to Earth. To get to Bennu, however, OSIRIS-REx must first leave the plane of Earth's orbit and match the orbital tilt of its target. On September 22, 2017, OSIRIS-REx will approach Earth and fly over its southern hemisphere, passing within 11,000 miles of Antarctica. This gravitational slingshot will bend its trajectory by six degrees, sending the spacecraft on a path to intercept Bennu. Shortly after the flyby, OSIRIS-REx will look back at Earth and take images and spectra, ensuring that its instruments are ready for arrival at Bennu in 2018.
https://www.youtube.com/watch?v=svq4-Kf4K2Ehttps://www.youtube.com/watch?v=svq4-Kf4K2E (1:35)

tnt22

https://spaceflightnow.com/2017/09/22/osiris-rex-earth-gravity-assist/
ЦитироватьOSIRIS-REx asteroid mission heads for Earth flyby
September 22, 2017 Stephen Clark

NASA's OSIRIS-REx spacecraft, en route to asteroid Bennu to retrieve samples and return them to scientists, will slingshot past Earth on Friday, using gravity to change its trajectory for a rendezvous with its target late next year.

One year since it launched fr om Cape Canaveral aboard an Atlas 5 rocket, OSIRIS-REx will return to Earth on Friday with a high-speed encounter taking the probe about 11,000 miles (17,000 kilometers) above Earth. The solar-powered spacecraft will make its closest approach to Earth at 1652 GMT (12:52 p.m. EDT) Friday, passing over Antarctica, just south of Cape Horn, Chile.
Спойлер

Artist's concept of the OSIRIS-REx spacecraft flying by Earth. Credit: NASA/Goddard Space Flight Center/University of Arizona

Navigators have confirmed OSIRIS-REx's trajectory will not go near any satellites or space junk tracked in Earth orbit, officials said.

OSIRIS-REx is approaching Earth at a relative velocity of 19,000 mph — more than 30,000 kilometers per hour — after traveling almost 600 million miles (1 billion kilometers) since its blastoff Sept. 8, 2016. The spacecraft spent the last year orbiting the sun, fine-tuning its flight path with several engine and thruster firings to aim for Friday's Earth flyby.

The spacecraft will get a gravitational kick fr om the encounter, employing Earth's gravity to redirect its orbit toward asteroid Bennu, an object measuring around 1,600 feet (500 meters) in diameter. Bennu circles the sun on a course tilted roughly 6 degrees from the plane of Earth's orbit, requiring OSIRIS-REx to fight against the sun's gravitational pull to reach the asteroid.

Friday's flyby will impart a change in OSIRIS-REx's velocity of around 8,400 mph — nearly 4 kilometers per second — around twice the adjustment possible if the spacecraft dedicated all of its fuel to the maneuver.

Manufactured by Lockheed Martin, OSIRIS-REx would have needed a much bigger, and more expensive, launcher to fly directly from Earth to Bennu, or carry a heavier load of fuel, a design change that would also have necessitated a larger rocket.

"It was a way to substantially save on resources, either on the spacecraft or on the launch vehicle, or both," said Dante Lauretta, OSIRIS-REx's principal investigator from the University of Arizona.

The gravity assist is similar to maneuvers used on many interplanetary missions, and the slingshot effect is natural, requiring no input from the spacecraft once it's on course for the flyby.

"For about an hour, NASA will be out of contact with the spacecraft as it passes over Antarctica," said Mike Moreau, the flight dynamics system lead at NASA's Goddard Space Flight Center. "OSIRIS-REx uses the Deep Space Network to communicate with Earth, and the spacecraft will be too low relative to the southern horizon to be in view with either the Deep Space tracking station at Canberra, Australia, or Goldstone, California."

NASA will regain communications with OSIRIS-REx around 1740 GMT (1:40 p.m. EDT), and the spacecraft will begin collecting imagery and calibration data with its science instruments around four hours after closest approach at a distance of around 60,000 miles (100,000 kilometers) from Earth.


OSIRIS-REx will approach Earth over the night side of the planet, then swing over the South Pole and depart over the Pacific Ocean in daylight. Credit: NASA/Goddard Space Flight Center/University of Arizona

According to Lauretta, OSIRIS-REx's three imaging cameras will look back at Earth and the moon for up to 10 days after the encounter, capturing close-up and long-range views, including a family portrait of the Earth-moon system.

The spacecraft is closing in on Earth above the night side of the planet, meaning the best views will come on OSIRIS-REx's outbound leg as it departs over the Pacific Ocean.

OSIRIS-REx's thermal emission spectrometer and visible and infrared spectrometer will also collect data on Earth for calibration, ensuring the accuracy of measurements gathered at Bennu. The mission's Canadian-built laser altimeter and a student-built dust experiment will not be fully activated until arrival at Bennu.

Images from the flyby will be released Tuesday, officials said.

"The spacecraft is doing extremely well," Lauretta said in an interview with Spaceflight Now. "We have checked out all of the spacecraft subsystems, and everything is woking as expected. The instruments have gone through two checkout and calibration campaigns."

OSIRIS-REx is short for the Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer, an approximately $1 billion mission funded by NASA to travel to asteroid Bennu, snag at least 2.1 ounces — 60 grams — of surface material, and return the specimens to Earth in September 2023.

Next up for the mission will be a series of course correction burns over the next year to set up for the final approach to Bennu.

Science observations of Bennu will begin in August 2018, and detailed images of Bennu should be acquired by OSIRIS-REx in October. Analysts will look for evidence of debris or moons in the asteroid's vicinity before OSIRIS-REx's arrival.

"The encounter, as the flight dynamicists think about it, happens in November of 2018," Lauretta said. "That's when we'll actually do a close approach over the north pole of the asteroid with an imaging campaign, and then do a couple of maneuvers and repeat that sequence multiple times."

OSIRIS-REx will go into orbit around the asteroid and identify locations wh ere the probe's sampling mechanism could scoop up material for return to Earth. The mission is the first asteroid sample return attempt mounted by NASA, and the second worldwide after Japan's Hayabusa mission brought back microscopic specimens from asteroid Itokawa in 2010.

Some time in July 2020, a robotic arm will reach down to the asteroid's surface with a device that will unleash a pulse of compressed nitrogen gas, scouring up bits of dust and rock into a collection chamber.

The spacecraft will leave Bennu in 2021 for the cruise back to Earth, wh ere it will drop the sample-carrying canister for re-entry and a parachute-assisted landing in Utah on Sept. 24, 2023. Scientists will inspect and analyze the samples in a special clean room at NASA's Johnson Space Center in Houston, looking for signs of organic molecules and other primordial building blocks that formed the planets and seeded life.

"This is really giving us a taste of what we're going to experience next year, and I think it's the start of building the excitement for our asteroid encounter," Lauretta said of Friday's flyby of Earth.
[свернуть]

tnt22

Цитировать Jonathan McDowell‏Подлинная учетная запись @planet4589 37 мин. назад

For the next half hour OSIRIS-Rex passes through the GEO altitude range but far to the south of the GEO belt. Now 40000 km above Adelaide

tnt22

http://spaceflight101.com/osiris-rex/osiris-rex-earth-gravity-assist/
ЦитироватьOSIRIS-REx Earth Gravity Assist sets up Distant Rendezvous with Asteroid Bennu
September 22, 2017


Image: NASA

Over a year after its launch, NASA's OSIRIS-REx spacecraft is inbound for a close flyby of Earth on Friday to use the planet's gravity to bend its flight path and place it on a course approaching asteroid Bennu next year for an up-close study of the ancient world including a daring touch-and-go maneuver to vacuum up sample material that is hoped to provide insight into the birth and early formation of the Solar System.

Friday's gravity assist brings the two-metric-ton OSIRIS-REx spacecraft to a closest approach at a distance of around 17,000 Kilometers, passing within the Geostationary Belt where the world's communications and weather satellites reside. The primary purpose of the maneuver is 'borrowing' some momentum fr om Earth to place the craft onto its approach path to Bennu for arrival in November 2018, but the flyby will also be utilized as a welcome opportunity to use the well-known Earth-Moon system to calibrate the spacecraft's instruments after a year in space.
Спойлер

OSIRIS-REx Roadmap to Bennu – Image: NASA/University of Arizona

The Lockheed-built OSIRIS-REx spacecraft departed Earth atop an Atlas V rocket on September 8, 2016 – lifting off fr om Florida's Space Coast and receiving a smooth ride on the two-stage rocket that accelerated it beyond Earth's gravitational grasp. Placed into a solar orbit of 0.78 x 1.23 Astronomical Units, inclined 0.2°, OSIRIS-REx was set for one year of mostly quiet cruising ahead of its re-rendezvous with planet Earth.

OSIRIS-REx completed a major Deep Space Maneuver on December 28, 2016 to change course toward its Earth gravity assist, firing the main engines to change its speed by 431 meters per second. The spacecraft made a 2.6-meter-per-second clean-up maneuver on January 18 to fine-tune its trajectory and a precise course correction on August 23 used the craft's Attitude Control System for a 77-second burn to change speed by 0.48 meters per second as a final setup maneuver for the flyby.

>> OSIRIS-REx Mission / Trajectory Design


Earth Gravity Assist Trajectory – Image: NASA

While coasting in its orbit around the sun, OSIRIS-REx went through a number of testing activities on its instruments and ten days in February were used to point the craft's Mapping Camera toward the Sun-Earth Lagrange Point 4 to look for Trojan asteroids – bodies captured at the L4 point and traveling around the sun ahead of Earth. No Trojans were discovered, but the experiment proved MapCam's sensitivity as a number of faint main belt asteroids were detected by the instrument.

The OSIRIS-REx spacecraft arrived back in Earth's Hill Sphere on September 19 wh ere Earth represents the primary gravitational force acting on the vehicle, altering its course. Closest approach occurs on Friday, September 22 at 16:51:45 UTC at an altitude of 17,237 Kilometers over Antarctica, due south of Cape Horn, at a relative speed of 30,670 Kilometers per hour.


Earth Gravity Assist Ground Track – Image: NASA

OSIRIS-REx dips below the Geostationary Orbit altitude at 15:32 UTC and communications will be lost for up to 55 minutes as the spacecraft fades below the horizon as seen from the Deep Space Network Station in Canberra, Australia around 16:45 UTC and the signal is re-acquired by Goldstone, California at 17:40 UTC. The spacecraft will rise above Geostationary Altitude at 18:11 UTC and make its closest approach to the Moon around ten hours after the flyby, coming no closer than 265,500 Kilometers.

The OSIRIS-REx mission team screened the spacecraft's path well ahead of time for any satellites or pieces of space debris to make sure there would be no close conjunction with any resident object in Earth orbit. As a precautionary measure, a pre-determined maneuver was ready to go into action the day before closest approach to have OSIRIS-REx change course in case of a late identified conjunction, but orbital data showed the craft would come no closer than 900 Kilometers to any known orbiting object.


Jupiter & three Galilean Moons captured by PolyCam – Image: NASA/Goddard/University of Arizona

OSIRIS-REx will depart Earth's Hill Sphere at 8:49 UTC on September 25 after the angular momentum exchange with Earth imparted a change in velocity of 3.778 Kilometers per second – around 90% more than what would be possible with the spacecraft's initial propellant load. The majority of delta-v provided by the Earth gravity assist is going into the plane-change maneuver, transitioning OSIRIS-REx from a 0.2-degree inclined solar orbit into a six-degree orbit to match Bennu's orbital tilt.

The target heliocentric orbit for OSIRIS-REx after the Earth flyby is 0.87 by 1.31 Astronomical Units, inclined 6.4 degrees. Asteroid Bennu orbits at 0.897 by 1.356 AU, 6.03°.

A number of science observations are planned to occur as OSIRIS-REx traverses the Earth-Moon System, approaching Earth from the night side before entering sunlight after the flyby. Initial observations are planned during a five-hour window opening at 20:52 UTC and more data will be collected at three, six and ten days after the flyby using the OSIRIS-REx Camera Suite (OCAMS), the OVIRS Visible and Infrared Spectrometer, the Thermal Emission Spectrometer, and the TAGCAMS cameras to be used during the sample collection operation at Bennu.

>> OSIRIS-REx Mission Section

>> Instrument Overviews


Image: NASA

Out of an abundance of caution, the OSIRIS-REx science team deactivated all instruments on the spacecraft a month before the gravity assist to eliminate any risk of an instrument-related safe mode on the spacecraft hampering any Trajectory Correction Windows. In total, OSIRIS-REx had three TCM windows to adjust its course, but only the first on August 23 was needed as the maneuver put the spacecraft on a very precise course. The instruments will be powered up two hours after closest approach if nothing unforeseen occurs.

A number of missions have used Earth Gravity Assist maneuvers as welcome opportunities for science calibration since the spectral properties of the Earth and Moon are very well understood after decades of studies, allowing instruments to be calibrated after spending an extended period in space. Exercising the instruments also provides knowledge on operational aspects like command sequences and other mission control elements that have to run smoothly when operating in proximity of Bennu.


Image: University of Arizona

The MapCam instrument will collect imagery at various distances with its field of view matching the size of the Pacific Ocean from a distance of around 100,000 Kilometers. The much narrower PolyCam will capture images at a resolution of 500 Kilometers on Earth's surface. For lunar observations, geometry does not play out favorably for OSIRIS-REx, looking at the Moon at less-than-ideal phase angles when imaging begins three days after the Earth flyby, though imaging will continue until the spacecraft is over one million Kilometers from Earth.

The OSIRIS-REx science team hopes to release initial photos from the spacecraft's passage through the Earth-Moon System on September 26. All in all, the spacecraft will capture nearly 1,000 images in the ten days after its flyby.

Outbound from Earth, OSIRIS-REx will go back into quiet coasting for another lap around the sun that will take it ever closer to asteroid Bennu. Another major Deep Space Maneuver on June 19, 2018 will mark the start of the craft's rendezvous with Bennu, comprising a series of additional maneuvers until PolyCam can acquire the asteroid in August 2018 for the start of the approach phase.


OSIRIS-REx before Launch – Photo: NASA Kennedy

OSIRIS-REx will arrive at Bennu in November 2018 for an initial period of formation flying at five Kilometers before heading into a one-Kilometer orbit around the asteroid, going through different surveying phases and touch-and-go rehearsals before attempting a critical maneuver to make contact with Bennu and collect up to two Kilograms of sample material. Depending on science-driven decisions, OSIRIS-REx could depart Bennu as early as January 2020 or as late as April 10, 2022 with the mission's baseline plan calling for the return of the sample on September 24, 2023 via parachute-assisted landing in Utah.

Asteroid Bennu is a dark, unexplored world roaming the Inner Solar System in an orbit taking it close to Earth every six years. This makes the 500-meter asteroid one of the more accessible bodies for a mission like OSIRIS-REx but also puts Bennu in the category of potential Earth impactors that could hit the planet at a future date.


Image: Lockheed Martin

Asteroids are often likened to time capsules from the early beginnings of the solar system, having not undergone significant alteration since the early stages of planetary formation. Therefore, carbon-rich asteroids like Bennu are considered a scientific treasure trove that could hold the answer to the question how the building blocks of life were delivered to Earth to permit life to develop.

Collecting a sample from the asteroid's surface and returning it to Earth for laboratory tests will enable scientists to look back to the very dawn of the Solar System and help understand the original inventory of organics present in this early stadium, feeding into processes that led to life and the habitability of planet Earth.

Sample return missions have the advantage of utilizing state-of-the-art laboratories for very precise analysis that can not be duplicated by any spacecraft instrument.

Carbon-rich asteroids have been identified as the likely candidates that delivered prebiotic compounds to Earth, organic molecules that became essential in the formation of life. Studying these processes will broaden our understanding of why we are here and how likely it is that these processes also led to the formation of life elsewh ere in the Solar System and even throughout the universe.
[свернуть]

tnt22

https://www.nasa.gov/feature/nasa-s-osiris-rex-spacecraft-slingshots-past-earth
ЦитироватьSept. 22, 2017

NASA'S OSIRIS-REx Spacecraft Slingshots Past Earth

NASA's asteroid sample return spacecraft successfully used Earth's gravity on Friday to slingshot itself on a path toward the asteroid Bennu, for a rendezvous next August.

At 12:52 p.m. EDT on Sept. 22, the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) spacecraft came within 10,711 miles (17,237 km) of Antarctica, just south of Cape Horn, Chile, before following a route north over the Pacific Ocean.
Спойлер
OSIRIS-REx launched from Cape Canaveral Air Force Station in Florida on Sept. 8, 2016, on an Atlas V 411 rocket. Although the rocket provided the spacecraft with the all the momentum required to propel it forward to Bennu, OSIRIS-REx needed an extra boost from the Earth's gravity to change its orbital plane. Bennu's orbit around the Sun is tilted six degrees from Earth's orbit, and this maneuver changed the spacecraft's direction to put it on the path toward Bennu.

As a result of the flyby, the velocity change to the spacecraft was 8,451 miles per hour (3.778 kilometers per second).

"The encounter with Earth is fundamental to our rendezvous with Bennu," said Rich Burns, OSIRIS-REx project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The total velocity change from Earth's gravity far exceeds the total fuel load of the OSIRIS-REx propulsion system, so we are really leveraging our Earth flyby to make a massive change to the OSIRIS-REx trajectory, specifically changing the tilt of the orbit to match Bennu."

The mission team also is using OSIRIS-REx's Earth flyby as an opportunity to test and calibrate the spacecraft's instrument suite. Approximately four hours after the point of closest approach, and on three subsequent days over the next two weeks, the spacecraft's instruments will be turned on to scan Earth and the Moon. These data will be used to calibrate the spacecraft's science instruments in preparation for OSIRIS-REx's arrival at Bennu in late 2018.

"The opportunity to collect science data over the next two weeks provides the OSIRIS-REx mission team with an excellent opportunity to practice for operations at Bennu," said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. "During the Earth flyby, the science and operations teams are co-located, performing daily activities together as they will during the asteroid encounter."

The OSIRIS-REx spacecraft is currently on a seven-year journey to rendezvous with, study, and return a sample of Bennu to Earth. This sample of a primitive asteroid will help scientists understand the formation of our solar system more than 4.5 billion years ago.

NASA's Goddard Space Flight Center provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission's science observation planning and data processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the agency's New Frontiers Program for the Science Mission Directorate in Washington.

Erin Morton
 University of Arizona, Tucson

Nancy Neal Jones
NASA's Goddard Space Flight Center, Greenbelt, Maryland
[свернуть]
Last Updated: Sept. 22, 2017
Editor: Karl Hille

tnt22

Цитировать Dante Lauretta‏ @DSLauretta 1 ч. назад

Congratulations @OSIRISREx team on a successful Earth Gravity Assist - trajectory is absolutely perfect - right up the middle!

tnt22

Цитировать Jonathan McDowell‏Подлинная учетная запись @planet4589 13 мин. назад

OSIRIS-Rex now heading away from Earth, range 108000 km and increasing

tnt22


che wi

«Охотник за астероидом» НАСА приблизился к Земле на пути к космическому камню

ЦитироватьКосмический аппарат НАСА, направляющийся к астероиду, использовал нашу планету для совершения гравитационного маневра в пятницу, двигаясь в направлении своей научной цели - космического камня.

Запущенный примерно год назад, космический аппарат Osiris-Rex прошел на расстоянии 17237 километров от нашей планеты в пятницу после обеда, пролетев над Антарктикой. Он использовал гравитацию Земли как «рогатку», благодаря которой аппарат лег на курс к астероиду Бенну.

Согласно плану зонд Osiris-Rex должен достичь этого небольшого, округлого астероида в следующем году, а в 2020 г. – отобрать с его поверхности несколько образцов грунта для возврата на Землю. Если все пройдет успешно, ученые должны получить эти образцы к 2023 г.

Пятничный пролет был довольно коротким по времени: космический аппарат мчался на скорости примерно 31000 километров в час. НАСА приняло предварительные меры, обеспечивающие безопасность спутников, находящихся на высоких орбитах, от столкновения с зондом Osiris-Rex, который по размеру сравним с легковым автомобилем.

Астероид Бенну составляет всего лишь примерно 500 метров в поперечнике и обращается вокруг Солнца по орбите, диаметр которой слегка превышает диаметр орбиты Земли. Научная станция Osiris-Rex войдет на орбиту вокруг этого астероида и будет производить поиск лучшего места на его поверхности для отбора нескольких крохотных порций грунта. Аппарат будет парить над поверхностью астероида, подобно колибри, в то время как механическая рука-манипулятор быстро опустится к поверхности и отберет при помощи всасывания немного грунта, перемешанного током азота, исходящего из двигателей космического аппарата.

Ученые говорят, что этот древний астероид может содержать ценные сведения о происхождении жизни. Считается, что он сформировался 4,5 миллиарда лет назад и является остатками «строительных кирпичиков» Солнечной системы.