At South by Southwest, SpaceX Founder and CEO Elon Musk projected that his first Mars spaceship will be ready for short trips by the first half of next year. He did warn, however, that the first travelers to Mars would likely perish.

“For the early people that go to Mars, it will be far more dangerous,” Musk told HLN on Monday. “I mean, really, it kind of reads like Shackleton’s ad for Antarctica explorers: It’s difficult, dangerous, good chance you’ll die, excitement for those who survive.”

This warning came after a positive declaration: “We are building the first ship, the first Mars or interplanetary ship right now and I think we’ll be able to do short flights, short up and down flights, probably in the first half of next year,” Musk predicted.

Musk referred to Ernest Shackleton, a polar explorer who led three British expeditions to the Antarctic and died in 1922. Shackleton is famous for putting out an advertisement in Britain’s The Times, supposedly reading as follows:

MEN WANTED for hazardous journey, small wages, bitter cold, long months of complete darkness, constant danger, safe return doubtful, honor and recognition in case of success.

According to legend, this ad received a tremendous response rate — 5,000 men approached Shackleton wishing to risk life and limb for glory. The entrepreneur organization the Shackleton Foundation championed this ad on Twitter.

Ironically, no historian has yet been able to prove that such an ad ever existed. The entire story itself may be a myth — but Musk’s reference to the famous ad may give it a real impact in history.

Musk’s warning that would-be Mars adventurers face a “good chance” of death, but unprecedented “excitement” should they survive, may be the real-life application of a historical myth.

Thousands, if not millions, of Americans and others across the world dream of reaching the stars, and reaching Mars would be a tremendous journey and accomplishment.

Such groundbreaking (or perhaps “atmosphere-breaking” would be more à propos) adventures often come with risks, and distinction for those who undertake them. Musk may have referenced a mythical ad with no historic proof it ever existed, but the spirit of Ernest Shackleton and the Shackleton Foundation is very much alive at SpaceX.

Click “Load More” to watch Musk’s warning below.