The added delay, however, will increase the pressure on government-run Nasa – whose rocket system for sending astronauts to the Moon, the Space Launch System (SLS), has been criticised as being expensive and slow to develop.
This is in stark contrast to Elon Musk’s private sector firm, SpaceX, which is surging ahead in its efforts to build its own, eventually much cheaper and reusable Starship rocket.
The nomination of Jared Isaacman by President-elect Donald Trump to take over from Mr Nelson as Nasa’s head has added to growing concerns that big changes are in store for Nasa’s Moon programme.
Mr Isaacman is a billionaire and close collaborator with Mr Musk, who has paid for two private sector missions which have taken him to space. His entrepreneurial approach might prove a shock to Nasa’s system, according to Dr Simeon Barber, a space scientist at the Open University.
“SLS is an old-school rocket. It is not reusable like Starship, hence very expensive, and it has taken a long time to get it operational. And slow and expensive is a precarious position to be in when the incoming president, we expect, is looking to save costs.
“Isaacman is going to bring a new pair of eyes over how Nasa operates. And it’s hard to predict what this combination of Isaacman, Musk and Trump might mean for Nasa as we know it.”
