Yesterday at 7.05pm EDT (00.05am BST this morning), NASA’s OSIRIS-REx mission successfully launched on a journey to an asteroid to teach us more about the early Solar System – and perhaps save Earth from disaster.

The flawless launch took place from Launch Complex 41 at Cape Canaveral in Florida atop an Atlas V rocket. Just under an hour after launching, at 8.04pm EDT (1.04am BST), OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) separated from the rocket and began its lone journey to asteroid 101955 Bennu.

“Today, we celebrate a huge milestone for this remarkable mission, and for this mission team,” said NASA Administrator Charles Bolden in a statement.

Now, the mission can begin in earnest, and we’ll have seven years of excitement until it comes to an end. The spacecraft will travel 7.2 billion kilometers (4.5 billion miles) to Bennu, arriving in August 2018. Once there, it will begin to survey the asteroid, and prepare to snag a sample with a robotic arm in July 2020.

After leaving the asteroid in March 2021, the sample – weighing between 60 grams and 2 kilograms (0.1 and 4.4 pounds) – will be returned to Earth in September 2023. It will be the first American sample from an asteroid and likely the largest sample returned since the Apollo missions.

^{OSIRIS-REx's Touch-And-Go Sample Acquisition Mechanism (TAGSAM) will grab a sample from the asteroid. NASA}

Bennu is interesting for a number of reasons. First and foremost, asteroids like this are believed to be remnants of the early Solar System. By retrieving a sample, scientists hope to discover the role asteroids may have played in delivering the components of life, and water, to Earth and perhaps other places.

Scientists also don’t know what Bennu looks like. We know it’s about 490 meters (1,600 feet) across, but we don’t know what sort of shape it is. Asteroids can come in all shapes and sizes, from long and narrow to more rounded. In less than two years, when OSIRIS-REx approaches Bennu and begins snapping images, we’ll know which category Bennu falls into.

Last but by no means least, Bennu also has a very small chance of hitting Earth in the next 200 years. NASA classes it as a potentially hazardous asteroid (PHA), and gives it a 1 in 2,500 chance of hitting Earth between 2175 and 2199. Given its size, it would cause untold damage if it did – so studying it should narrow down whether we’ve got anything to worry about or not.

With NASA’s Cassini spacecraft due to come to an end in September 2017 and ESA’s Rosetta mission ending this month, hopefully OSIRIS-REx can fulfill our yearning for more Solar System exploration. Get ready for one hell of a ride – but here’s hoping it goes slightly smoother than the first ever asteroid sampling mission, Japan’s Hayabusa last decade.