Miami: The US space agency launched its first mission to collect dust from an asteroid, the kind of cosmic body that may have delivered life-giving materials to Earth billions of years ago.
The unmanned spacecraft, known as OSIRIS-REx, blasted off at 7:05 pm (local time) atop an Atlas V rocket in Cape Canaveral, Florida.
The $800 million mission will travel for two years on a journey to Bennu, a near-Earth asteroid about the size of a small mountain.
Bennu was chosen from the some 5,00,000 asteroids in the solar system because it orbits close to Earth's path around the sun, it is the right size for scientific study, and it is one of the oldest asteroids known to Nasa.
"For primitive, carbon-rich asteroids like Bennu, materials are preserved from over four and a half billion years ago," explained Christina Richey, OSIRIS-REx deputy program scientist at Nasa.
These "may be the precursors to life in Earth or elsewhere in our solar system".
OSIRIS-REx's main goal is to gather dirt and debris from the surface of the asteroid and return it to Earth by 2023 for further study.
Learning more about the origins of life and the beginning of the solar system are key objectives for the SUV-sized OSIRIS-REx, which stands for Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer.
The mission should also shed light on how to find precious resources such as water and metals in asteroids, a field that has generated increasing interest worldwide.
"We are going to map this brand-new world that we have never seen before," said Dante Lauretta, OSIRIS-REx principal investigator and professor at the University of Arizona, Tucson.
Using a suite of cameras, lasers and spectrometers, "we are really going to understand the distribution of materials across the surface of that asteroid," he added.
"We are a trailblazer for that kind of activity because our science requires it."
The spacecraft is expected to reach Bennu in August 2018 and spend two years studying it before it begins the sample collection attempt in July 2020.
Nasa hopes the solar-powered OSIRIS-REx will bring back the largest payload of space samples since the Apollo era of the 1960s and 1970s, when American explorers collected and carried back to Earth some 800 pounds (360 kilogrammes) of moon rocks.
The collection device, known as the Touch-and-Go Sample Acquisition Mechanism (TAGSAM), should pick up about two ounces (60 grams) from the asteroid, but in tests so far it has generally picked up five times that amount.
TAGSAM contains a type of reverse-vacuum mechanism that was invented by a Lockheed Martin engineer who tested the concept a decade ago using a red plastic Solo cup in his driveway.