Nav: Home

NASA to map Asteroid Bennu from the ground up

August 11, 2016

How do you study the topography of an asteroid millions of miles away? Map it with a robotic cartographer!

NASA's Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx, will launch in September 2016 and travel to a near-Earth asteroid known as Bennu to harvest a sample of surface material and return it to Earth for study. But before the science team can select a sample site, it needs to know a little something about the asteroid's topography.

The OSIRIS-REx Laser Altimeter, or OLA, is provided by the Canadian Space Agency and will be used to create three-dimensional global topographic maps of Bennu and local maps of candidate sample sites.

"OLA will measure the asteroid's topography and shape in a detail that is unprecedented compared to other asteroid missions," said Michael Daly, OLA instrument scientist at York University in Toronto, Canada. " This 3-D shape will be the foundational dataset for the other instruments."

Think of your favorite computer animated movie. The characters and environment are colored and shaded in such a way that they look almost lifelike. But all of those details need a 3-D shape in order to take form. The same is true for the detailed data gathered by OSIRIS-REx's instruments.

To create these 3-D models, OLA uses LIDAR, which stands for light detection and ranging. LIDAR is similar to radar, but uses light instead of radio waves to measure distance. OLA will emit infrared laser pulses toward the surface of Bennu as the spacecraft moves around the asteroid. The laser pulses reflect back from the surface to a detector. The team will measure the time difference between outgoing and incoming pulses to calculate the distance between the spacecraft and Bennu.

LIDAR has been used on prior spacecraft, including the Mars Global Surveyor and the Lunar Reconnaissance Orbiter. Those laser altimeters are fixed to the spacecraft, meaning that the laser pulse will only travel in the direction that the spacecraft is pointing. This can limit the coverage and spatial resolution of their topographic maps. So, while they have generated a vast amount of data, fixed LIDAR are not ideal for missions where the data must be gathered quickly.

"OLA is the first scanning LIDAR to fly on a planetary mission," said Beau Bierhaus, an OLA team member at Lockheed Martin. "Because the LIDAR can articulate independently of the spacecraft, the LIDAR provides improved operational flexibility, and more importantly, much greater spatial coverage and resolution."

OLA is expected to thoroughly map Bennu with about 6 billion measurements of the asteroid's surface, which measures about one-third of a mile (one-half kilometer) in diameter. In comparison, the laser altimeter on the Lunar Reconnaissance Orbiter has received more than 6.8 billion measurements of the surface of the moon, which has a diameter of about 2,159 miles (3,500 kilometers).

The fundamental data of the asteroid's shape and topography that OLA will provide are essential for several key phases during the mission.

The science team will use the high-resolution topographic data, in conjunction with camera images and on-board navigation algorithms, to navigate around the asteroid and guide the spacecraft to the selected sample site.

"We're measuring topography down to one centimeter," said Olivier Barnouin, the Altimetry Working Group lead at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. "We're looking at an asteroid at a scale that no other mission has before. We don't want to be off in some unknown area during sample acquisition."

The three-dimensional maps will also give geologic context to the returned asteroid sample. Just as geologists on Earth document where they collect their samples in the field on topographic maps, OLA will allow the science team to take their measurements and observations of the collected sample and apply them to their broader understanding of Bennu.

OLA will also allow the science team to study how regolith, or loose surface material, behaves in a microgravity environment. Scientists have done similar studies on the moon and Mars, but unlike Bennu, these bodies have relatively high gravity.

"What happens on asteroids is that you take that gravity dial and turn it way down," Bierhaus said. "The dynamics of how regolith moves on the surface of the asteroid are foreign to us. OLA data will give us a greater understanding of how granular material behaves in space."

This understanding is especially important for future asteroid missions. Scientists will need to know how regolith behaves in micro-gravity environments if we want to send astronauts to an asteroid someday to collect samples.

"Collaborating on this project reminds us of the unique relationship between Canada and the United States," said Daly. "It provides both countries access to additional technological expertise and people that they would not otherwise have."

Goddard will provide overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission's principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver built the spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency's Science Mission Directorate in Washington.
For more information about OSIRIS-REx, visit:

NASA/Goddard Space Flight Center

Related Asteroid Articles:

An iron-clad asteroid
Mineralogists from Jena and Japan discover a previously unknown phenomenon in soil samples from the asteroid 'Itokawa': the surface of the celestial body is covered with tiny hair-shaped iron crystals.
Asteroid impact enriches certain elements in seawater
University of Tsukuba researchers found two processes immediately after the end-Cretaceous asteroid impact that likely supplied chalcophile elements to the ocean, i.e., impact heating and acid rain.
Turbulent times revealed on Asteroid 4 Vesta
Planetary scientists at Curtin University have shed some light on the tumultuous early days of the largely preserved protoplanet Asteroid 4 Vesta, the second largest asteroid in our solar system.
In death of dinosaurs, it was all about the asteroid -- not volcanoes
Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers.
Active asteroid unveils fireball identity
At around 1 a.m. local standard time on April 29, 2017, a fireball flew over Kyoto, Japan.
It really was the asteroid
Fossil remains of tiny calcareous algae not only provide information about the end of the dinosaurs, but also show how the oceans recovered after the fatal asteroid impact.
Gigantic asteroid collision boosted biodiversity on Earth
An international study led by researchers from Lund University in Sweden has found that a collision in the asteroid belt 470 million years ago created drastic changes to life on Earth.
Uncovering the hidden history of a giant asteroid
A massive 'hit-and-run' collision profoundly impacted the evolutionary history of Vesta, the brightest asteroid visible from Earth.
Hubble watches spun-up asteroid coming apart
A small asteroid has been caught in the process of spinning so fast it's throwing off material, according to new data from NASA's Hubble Space Telescope and other observatories.
Hubble captures rare active asteroid
Thanks to an impressive collaboration bringing together data from ground-based telescopes, all-sky surveys and space-based facilities -- including the NASA/ESA Hubble Space Telescope -- a rare self-destructing asteroid called 6478 Gault has been observed.
More Asteroid News and Asteroid Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Producer Tracie Hunte stumbled into a duet between Nina Simone and the sounds of protest outside her apartment. Then she discovered a performance by Nina on April 7, 1968 - three days after the assassination of Dr. Martin Luther King Jr. Tracie talks about what Nina's music, born during another time when our country was facing questions that seemed to have no answer, meant then and why it still resonates today.  Listen to Nina's brother, Samuel Waymon, talk about that April 7th concert here.