Mars One Settlement
Artist's concept of a Mars One settlement. Mars One/Bryan Versteeg

Remember Mars One? The private spaceflight company that, in 2012, unveiled its ambitious plan to send humans to the red planet in 2023 has announced another delay in its mission.

In a statement released Wednesday, Mars One said that it now expects to send its first crew of four astronauts to Mars in 2031 — eight years beyond its original target and five years after its most recent deadline of 2026 expires.

“In order to make Mars One's commercial activities an attractive investment with the potential of a good return on investment, Mars One had to adjust the timing of the planned unmanned and manned missions,” Mars One co-founder and CEO Bas Lansdorp said in the statement. “This pushes the large expenses associated with the mission hardware back in time, making the company cash positive sooner. The delay we are currently announcing is also because it took us longer to get to this point than we originally anticipated.”

Prior to the launch of the crewed mission, Mars One envisions sending a communications satellite to orbit the planet by 2024, followed by the launch of a rover in 2026. A second rover, along with the equipment needed to support astronauts on Mars, will be sent in 2029.

“Of course the whole Mars One team would have preferred to be able to stick to the original schedule, but this new timeline significantly improves our odds of successfully achieving this mission roadmap,” Lansdorp added.

When Mars One first announced its Mars colonization plans in 2012, roughly 200,000 people signed up to be part of the project. Since then, using criteria that have faced their fair share of criticism, the number has been whittled down to 100, which Mars One says would be further cut to less than 50.

However, the constantly shifting mission deadlines are just one of Mars One’s many worries. Although the company has previously announced that it plans to use SpaceX’s Falcon Heavy rocket to get to Mars, details of the spacecraft, habitation modules, spacesuits and life-support systems it plans to use have still not been revealed.

“The hardware specifically needed for this mission still needs to be designed, built, and tested extensively but the technology already exists,” Mars One, which was recently acquired by the Swiss financial services company InFin Innovative Finance, says on its website.

In 2014, a team of graduate students from the Massachusetts Institute of Technology analyzed — using computer-generated models to simulate the day-to-day life of a Mars colonist — the company’s plans, and found them to be “overly optimistic.”

“We’re not saying, black and white, Mars One is infeasible,” Olivier de Weck, an MIT professor of aeronautics and astronautics, who was part of the team that performed the assessment, said in a statement in October 2014. “But we do think it’s not really feasible under the assumptions they’ve made.”