In context: When the space shuttle program ended in 2011, the Atlantis shuttle wasn't the last vehicle to be retired. That honor went to the Astrovan, a modified Airstream motor home that took the shuttle crew home after they landed.

For 27 years, the Astrovan carried the shuttle crews nine miles from their spacesuit-changerooms to the launchpad. And it was there to pick them up when they touched down. It only drove a thousand miles per year, but they were some of the most-watched miles ever driven.

"You're a little bit nervous, but it's neat to know that you're one in a series of a very long line of astronauts who rode in this vehicle going to the pad for flight to space," astronaut Doug Hurley said of the Astrovan. "It's pretty cool."

But now that the manned Artemis 2 mission is tentatively on the calendar – for "late 2023 or early 2024" – the need to find a replacement for the Astrovan has become apparent. NASA has announced that they're looking for people or businesses to make a new "Artemis Crew Transportation Vehicle" for them.

It'll have to comply with their very long list of requirements, which begins with a statement about its importance: "the CTV shall visually embody Artemis to the public; and safely and securely transport the Astronauts and support personnel."

The CTV needs to fit at least seven passengers, including four fully suited-up astronauts, plus a driver. It needs to have doors wide enough for the astronauts to fit through, and enough storage space for half a dozen large equipment bags and the astronaut's cooling units. It also needs to be electric.

NASA says they're interested in three types of vehicles: one built from scratch, a modified commercial vehicle, and a refurbishment of the Astrovan.

The last option appeals the most to the astronauts. "I would like to keep [the] tradition," Hurley said in 2011. "I don't know if any of us will get to fly on the next US vehicle, whatever that vehicle may be. It would be kind of neat to have some of it be the same."

Potential applicants have one month to register their interest in the project.