Gone Bennu hunting: The OSIRIS-REx launch

On the day that marked half a century since the first "Star Trek" episode aired on TV, a NASA space probe boldly took off toward an asteroid called Bennu on Thursday, to dig up and bring back some cosmic dust that could hold clues to the birth of our solar system.

It's another example of NASA "turning science fiction into science fact," said NASA's chief scientist Ellen Stofan from the launch location in Cape Canaveral, Fla., where thousands had gathered for the sendoff.

A robotic hunter that resembles a bird with solar-panel wings outstretched, the OSIRIS-REx spacecraft was launched into space before sunset atop an Atlas V rocket on Thursday. The SUV-sized robot is expected to travel for two years to reach its destination: a huge rock that’s orbiting the sun at a slightly wider orbit than Earth. Bennu is about a third of a mile wide and taller than the Empire State Building.

Once the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft reaches the asteroid in 2018, it will spend up to two years mapping Bennu’s surface and studying its chemical and mineral composition.

Then, if all goes according to plan, it will dig in.

To do so, OSIRIS-REx will have to hover over Bennu while stretching its 10-foot robotic arm down to the surface. The spacecraft’s thrusters will puff out nitrogen gas to stir up the surface so that loose gravel and dirt can be sucked up into the spacecraft's collection device.

Though scientists have studied Bennu from ground and space telescopes, they don’t know exactly what to expect on its surface, so there will be some anxiety down on Earth as OSIRIS-REx works to collect its samples. Scientists expect to get have three chances to collect what they need before the nitrogen gas runs out.

Overall, the nearly $1 billion mission is expected to take about seven years and 4 billion miles of travel to complete. NASA hopes to collect at least 2 ounces of cosmic dust, to be returned to Earth in a capsule released from Osiris-REx on its return trip. If all goes well, the priceless asteroid fragments will parachute down to the Utah desert in September 2023.

NASA plans to share the contents with labs across the globe, which hope to study the carbon-rich asteroid rock for years. Since asteroids are the rubble left over from the formation of the planets, even a pebble can hold clues to the birth of the solar system. Researchers hope that Bennu, which is a particularly carbon-rich asteroid, will offer insights into the development of organic life.

Most scientists agree that asteroids and comets delivered the water and carbon that were instrumental to life here as they crashed into a forming Earth. Others give credit to a massive proto-planetary collision. The samples from Bennu could resolve the question.

"You can think of these asteroids as literally prebiotic chemical factories that were producing building blocks of life 4.5 billion years ago, before Earth formed, before life started here," said NASA astrobiologist Daniel Glavin before launch.

OSIRIS-REx is NASA's first asteroid sampling mission. The space agency last collected space rocks on the Moon during the Apollo program.

As The Christian Science Monitor’s Joseph Dussault reported on Wednesday:

The last time the agency launched a major sampling mission, Richard Nixon was president and “The Brady Bunch” was in its first season. Between 1969 and 1972, the Apollo program brought an 842-pound haul of lunar rock back to Earth. Those rocks still being studied.

Only Japan's Hayabusa spacecraft has previously returned samples from an asteroid to Earth, but because of technical problems it didn’t collect a big enough sample. The Hayabusa 2 mission launched in 2014 and is scheduled to return to Earth in December 2020.

This report uses material from the Associated Press and Reuters.