Radiosignaler bruker 18,5 minutter til jorden. Avstanden fra solen til jorden tilsvarer litt over 8 minutter. Størrelsen på asteroiden er omtrent som Empire State Building. Asteroiden ble skapt omtrent på samme tid som planetene. Derfor er forskning på denne viktig. (Red)
NASA mission successfully touched down on asteroid Bennu
(CNN)After orbiting the near-Earth asteroid Bennu for nearly two
years, NASA's OSIRIS-REx spacecraft successfully touched down and reached out
its robotic arm to collect a sample from the asteroid's surface on Tuesday.
That
sample will be returned to Earth in 2023.
To achieve
this historic first for NASA, a van-size spacecraft had to briefly touch down
its arm in a landing site called Nightingale. The site is the width of a few
parking spaces.
The arm
reached out to collect a sample, which could be between 2 ounces and 2
kilograms. Then, the spacecraft backed away to safety.
Sjekk video her: https://tinyurl.com/y4pu3bdz
Everything went perfectly based on the data returned by the spacecraft,
according to Dante Lauretta, the mission's principal investigator and a
professor at the University of Arizona Lunar and Planetary Laboratory. He said
he feels "transcendent" and the team is "exuberant" based
on the current data.
On Tuesday
night, the OSIRIS-REx team will go through the data being sent back by the
spacecraft.
"After
over a decade of planning, the team is overjoyed at the success of today's
sampling attempt," Lauretta said in a statement. "Even though we have
some work ahead of us to determine the outcome of the event -- the successful
contact, the TAGSAM gas firing, and back-away from Bennu are major
accomplishments for the team. I look forward to analyzing the data to determine
the mass of sample collected."
The agency
will be able to confirm if a sample was successfully collected later and images
of the event will be available Wednesday on NASA's site.
"This
was an incredible feat -- and today we've advanced both science and engineering
and our prospects for future missions to study these mysterious ancient
storytellers of the solar system," said Thomas Zurbuchen, associate
administrator for NASA's Science Mission Directorate in a statement. "A
piece of primordial rock that has witnessed our solar system's entire history
may now be ready to come home for generations of scientific discovery, and we
can't wait to see what comes next."
The site
itself is nestled within a crater the size of a tennis court and ringed in
building-size boulders.
Located
more than 200 million miles from Earth, Bennu is a boulder-studded asteroid
shaped like a spinning top and as tall as the Empire State Building. It's a
"rubble pile" asteroid, which is a grouping of rocks held together by
gravity rather than a single object.
The mission -- which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer -- launched in September 2016.
Since
arriving at Bennu, the spacecraft and its cameras have been collecting and
sending back data and images to help the team learn more about the asteroid's
composition and map the best potential landing sites to collect samples.
The main
event of the mission is the Touch-and-Go sample collection event, or TAG, that
occurred today.
Bennu has
an orbit that brings it close to Earth, which is why it's considered to be a
near-Earth asteroid. One of its future approaches could bring it perilously
close to Earth sometime in the next century; it has a one in 2,700 chance of
impacting our planet.
The
samples from Bennu could help scientists understand not only more about
asteroids that could impact Earth but also about how planets formed and life
began.
"Today's
TAG maneuver was historic," said Lori Glaze, Planetary Science Division
director at NASA Headquarters in Washington, in a statement. "The fact
that we safely and successfully touched the surface of Bennu, in addition to
all the other milestones this mission has already achieved, is a testament to
the living spirit of exploration that continues to uncover the secrets of the
solar system."
Waiting for the moment
Rather
than the so-called "seven minutes of terror" of trying to land the Perseverance rover on Mars next year, the
OSIRIS-REx team has experienced "4.5 hours of mild anxiousness,"
according to Beth Buck, the mission's operations program manager at Lockheed
Martin Space in Littleton, Colorado.
The event
officially started at 1:57 p.m. ET.
During
this time, the spacecraft descended from its orbit around the asteroid and came
close enough to touch it.
The
asteroid and spacecraft are currently about 207 million miles from Earth, which
cause a communication delay of about 18.5 minutes between the mission's team
and the spacecraft.
This asteroid is ejecting particles
into space. A spacecraft may tell us why
The team at NASA has been sharing animations on
the mission's Twitter account depicting what is occurring based on the commands
that have already been sent to OSIRIS-REx hours ahead for the sample collection
sequence.
A livestream also
began at 5 p.m. ET on NASA's site that shares animations and insight from the
mission team as they explain the data they're receiving.
The
spacecraft performed the entire sequence of approaching the asteroid and
collecting the sample autonomously since live commands from Earth were not
possible.
Touching down on an asteroid
The event
took about 4.5 hours total to unfold and the spacecraft executed three
maneuvers to collect the sample.
The
spacecraft fired thrusters to leave its safe orbit around the asteroid, which
is about 2,500 feet away from the surface, and traveled for a total of four
hours before reaching just 410 feet away. Then, the spacecraft adjusted for
position and speed to continue descending.
OSIRIS-REx
then slowed its descent to target a path so it matched the asteroid's rotation
during contact. Its solar panels folded into a Y-wing configuration above the
spacecraft to protect them.
Photos: OSIRIS-REx will take a sample of asteroid Bennu and
return it to Earth
At last,
OSIRIS-REx touched down for less than 16 seconds. The spacecraft fired a
pressurized nitrogen bottle into the asteroid, using the gas as a way to lift
material off Bennu's surface.
If sample
collection occurred as planned, the spacecraft's collector head captured the
stirred up material. This head, located on the 11-foot-long robotic sampling
arm, is the only part of the spacecraft that touched Bennu. The team compares
it to an air filter in an older model car, perfect for collecting fine
material.
Small discs, which can collect dust like sticky pads, are also located on the
head in case part of the sampling maneuver didn't go according to plan.
After the event
A camera
on the spacecraft has captured footage of the collection event.
The
OSIRIS-REx spacecraft was tasked with detecting hazards and delaying its own
mission if any obstacles were to get in the way of the sample collection. Based
on its simulations, the team estimated there was less than a 6% chance the
spacecraft would abort the mission.
Imagery
will be returned by the spacecraft on Wednesday, which will provide more
details of the sample collection and how the spacecraft is faring.
"It's
hard to put into words how exciting it was to receive confirmation that the
spacecraft successfully touched the surface and fired one of the gas
bottles," said Michael Moreau, OSIRIS-REx deputy project manager at NASA's
Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
"Our
first indication of whether we were successful in collecting a sample will come
on October 21 when we downlink the back-away movie from the spacecraft,"
Moreau said. "If TAG made a significant disturbance of the surface, we
likely collected a lot of material."
The team
estimates that they will have a mass measurement of the sample on Saturday. By
October 30, NASA will confirm if the spacecraft collected enough of a sample or
if it needs to make another sample collection attempt in January at another
landing site called Osprey.
But if
everything runs smoothly, the spacecraft and its prized sample will begin the
long journey back to Earth next year and land the sample on Earth in 2023.
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