For the first time, NASA is planning to open the International Space Station to private citizens, allowing commercial companies to arrange tours that could cost as much as $58 million per person, officials said at a news conference Friday.

The first phase of the plan will allow up to two private astronauts to make short-term visits to the station as soon as 2020, before opening the station to other tourism opportunities.

NASA said the commercial activity is an effort to raise money for sending a new round of astronauts to the moon by 2024.

Hours after the announcement, President Donald Trump tweeted that he does not think NASA should focus on returning to the moon and should instead turn its attention toward Mars (while incorrectly stating the Moon is a part of Earths neighboring planet). Trump just last month said he was beefing up NASAs budget and we are going back to the Moon.

The space tourist visits will be arranged through commercial companies contracted with NASA, which currently include Boeing and Elon Musks Space X. The agency is evaluating proposals from additional companies.

The companies will have to pay about $35,000 a night to use the space stations services, including air, water, food and communication, NASA said. Voyagers would be charged much more, to cover costs of the companies rocket flights and other expenses.