NASA says taking sample from asteroid harder than expected

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This February 27, 2018 photo from NASA’s OSIRIS-REx spacecraft, obtained March 18, 2019 courtesy of NASA/Goddard/University of Arizona, shows a close up of the asteroid Bennu from a distance of 0.8 miles (1.3 km). (AFP)
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This December 2, 2018 photo from NASA’s OSIRIS-REx spacecraft, obtained March 18, 2019 courtesy of NASA/Goddard/University of Arizona, shows a mosaic image of asteroid Bennu, composed of 12 PolyCam images, from a distance of 12 miles (124 km). (AFP)
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This artist's rendering made available by NASA in July 2016 shows the mapping of the near-Earth asteroid Bennu by the OSIRIS-REx spacecraft. (AP)
Updated 20 March 2019
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NASA says taking sample from asteroid harder than expected

  • The asteroid, which orbits the sun, is 85 million kilometers (52 million miles) from the Earth
  • The samples will be stowed in the probe, which will return to Earth in 2023

WASHINGTON: After two years crossing the solar system, the NASA space probe Osiris-Rex arrived last December near the asteroid Bennu to complete its mission of collecting a sample — but touching the rock will prove much harder than scientists had expected.
The Osiris-Rex team said Tuesday that the surface of the asteroid, which measures 490 meters (1,600 feet) in diameter, was covered in stones and boulders. They had expected it to be smoother and easier for the probe to touch.
“We go back to the drawing board and start thinking again,” Dante Lauretta, the head of the mission, told a press conference. The team’s observations also appeared in the Nature journal on Tuesday.
The probe was designed to head for a flat area with a radius of 25 meters, but the images beamed back since December showed that there is no area that big which is free of boulders.
As a result, the team will have to aim more tightly.
“Now we’re going to try to hit the center of the bullseye,” said project manager Richard Burns.
Since December, the probe has been using its instruments to map Bennu from a close distance, currently three miles.
The asteroid, which orbits the sun, is 85 million kilometers (52 million miles) from the Earth.
The goal is touch the surface with a robotic arm for just five seconds in July 2020, retrieving a sample of between 60 grams and two kilograms (two ounces to 4.4 pounds) of regolith, which means relatively small particles such as gravel or sand, since the machine can only suck up particles measuring less than two centimeters.
The samples will be stowed in the probe, which will return to Earth in 2023.
Bennu is technically known as “rubble-pile asteroid,” that is, it is made up of pieces of debris that had broken off larger celestial bodies and come together under the effect of gravity.
It has more than 200 boulders larger than 10 meters in diameter, and some stretching up to 30 meters, according to researchers writing in Nature Astronomy. It has a number of craters between 10 and over 150 meters in length.
“It is not trivial to deliver a spacecraft with meter scale resolution to the surface of an asteroid in the microgravity environment,” said Lauretta, who nevertheless said he was “confident” that the team would rise to the challenge.
Another surprise Bennu had been withholding was that it emits particles which fall back to the surface like rain. That should not however endanger the probe, the team said.


NASA probe detects likely ‘marsquake’ — an interplanetary first

A life-size model of the spaceship Insight, NASA's first robotic lander dedicated to studying the deep interior of Mars, is shown at Jet Propulsion Laboratory (JPL) in Pasadena, California, U.S. November 26, 2018. (REUTERS)
Updated 24 April 2019
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NASA probe detects likely ‘marsquake’ — an interplanetary first

  • A more distant quake would yield greater information about Mars’ interior because seismic waves would “penetrate deeper into the planet before they come back up to the seismometer,” he said

CALIFORNIA: NASA’s robotic probe InSight has detected and measured what scientists believe to be a “marsquake,” marking the first time a likely seismological tremor has been recorded on another planet, the Jet Propulsion Laboratory in California reported on Tuesday.
The breakthrough came nearly five months after InSight, the first spacecraft designed specifically to study the deep interior of a distant world, touched down on the surface of Mars to begin its two-year seismological mission on the red planet.
The faint rumble characterized by JPL scientists as a likely marsquake, roughly equal to a 2.5 magnitude earthquake, was recorded on April 6 — the lander’s 128th Martian day, or sol.
It was detected by InSight’s French-built seismometer, an instrument sensitive enough to measure a seismic wave just one-half the radius of a hydrogen atom.
“We’ve been collecting background noise up until now, but this first event officially kicks off a new field: Martian seismology,” InSight principal investigator Bruce Banerdt said in a news release.
Scientists are still examining the data to conclusively determine the precise cause of the signal, but the trembling appeared to have originated from inside the planet, as opposed to being caused by forces above the surface, such as wind.
“The high frequency level and broad band is very similar to what we get from a rupture process. So we are very confident that this is a marsquake,” Philippe Lognonné, a geophysics and planetary science professor at University Paris Diderot in France and lead researcher for InSight’s seismometer, said in an email.
Still, a tremor so faint in Southern California would be virtually lost among the dozens of small seismic crackles that occur there every day.
“Our informed guesswork is that this a very small event that’s relatively close, maybe from 50 to 100 kilometers away” from the lander, Banerdt told Reuters by telephone.
A more distant quake would yield greater information about Mars’ interior because seismic waves would “penetrate deeper into the planet before they come back up to the seismometer,” he said.
 
The size and duration of the marsquake also fit the profile of some of the thousands of moonquakes detected on the lunar surface between 1969 and 1977 by seismometers installed there by NASA’s Apollo missions, said Lori Glaze, planetary science division director at NASA headquarters in Washington.
The lunar and Martian surfaces are extremely quiet compared with Earth, which experiences constant low-level seismic noise from oceans and weather as well as quakes that occur along subterranean fault lines created by shifting tectonic plates in the planet’s crust.
Mars and the moon lack tectonic plates. Their seismic activity is instead driven by a cooling and contracting process that causes stress to build up and become strong enough to rupture the crust.
Three other apparent seismic signals were picked up by InSight on March 14, April 10 and April 11 but were even smaller and more ambiguous in origin, leaving scientists less certain they were actual marsquakes.
Lognonné said he expected InSight to eventually detect quakes 50 to 100 times larger than the April 6 tremor.