A group of private astronauts are journeying home through outer space after spending a little more than two weeks at the International Space Station.

A sonic boom might announce the return of a SpaceX spacecraft from the International Space Station before it splashes down off the California coast.

The astronauts arrived at the station on June 26, about 28.5 hours after launch from NASA's Kennedy Space Center atop SpaceX's Falcon 9 rocket on June 25. Over the last two weeks, the crew conducted more than 60 experiments focused on microalgae, microbial growth and human health and have travelled over 10 million kilometres in space.