Could we actually land humans on Mars in 2024? That’s the insane plan announced by none other than SpaceX founder Elon Musk himself recently, but not surprisingly, many are wary of the notorious hype man’s extravagant claims during a speech in Adelaide, Australia on Friday.

The billionaire said that he hoped to get crews on the Red Planet in just seven years, and the first cargo flights there in 2022. And you thought NASA’s push to put mankind on Mars in the mid 2030s was ambitious.

Musk says he’ll try to land two cargo ships on Mars in 2022 to identify available water as well as hazards that could impact a human settlement. The cargo mission would also set up power, mining, and life support infrastructure so that things are set up when humans arrive.

Then, in 2024, two ships carrying humans would be sent with more cargo vessels, which would also result in the setup of a rocket fuel production plant and colony base that could be further expanded in the future. By producing rocket fuel on the planet, Musk is hoping to make it possible for return trips. He thinks this can be done by harvesting carbon dioxide from the Martian atmosphere.

Naturally, many people are skeptical. First of all, the rocket that would carry people to Mars hasn’t even been actually built yet. There are a gazillion problems that may crop up during testing. Then there are the political and social obstacles, concerns about planetary protection, and a host of other things.

NASA itself appears hesitant to sign off on the ambitious plan by Musk.

“NASA is excited to see continued global interest in moving human exploration farther into the solar system, including Mars,” reads a NASA statement as printed by The Australian. “A sustainable crew presence in deep space will require the best of NASA, our international partners and the private sector. Therefore, the agency is studying the deep space gateway concept with US industry and space station partners for potential future collaborations.”