Elon Musk has told SpaceX employees to focus on the mission to send people to the moon and Mars as their top priority following the company’s success in sending astronauts into orbit last month.

Musk called on employees to accelerate the pace of progress for the company’s Starship rocket program “dramatically and immediately,” CNBC reported, citing a company-wide email it had seen.

“Please consider the top SpaceX priority (apart from anything that could reduce Dragon return risk) to be Starship,” Musk wrote.

Starship is aimed to be fully reusable and function more like a commercial airplane, with the goal of carrying as many as 100 people at a time.

SpaceX’s Falcon 9 rocket successfully sent two astronauts into space to board the International Space Station, marking the first time humans have been sent into orbit in a commercially developed craft.

SpaceX did not immediately respond to CNBC’s request for comment on Musk’s email.