In a major milestone for American spaceflight, NASA’s Orion spacecraft is set to take its first test flight early Thursday morning.

Though this mission will be unmanned, the Orion capsule will eventually carry astronauts on deep space missions. It is NASA’s hope that the Orion spacecraft will take astronauts to asteroids in the 2020s and Mars in the 2030s.

Taking a page from Joe Biden’s playbook, NASA Administrator Charles Bolden told one audience that this mission is a B.F.D. – a big (fill in the blank) deal.

Mounted to a Delta IV heavy rocket, the Orion space capsule is expected to blast off from Cape Canaveral at 6:05 a.m. CST. Exploration Flight Test 1 (or EFT-1) will last 4.5 hours as the spacecraft completes two orbits, eventually climbing to more than 3,600 miles above Earth. For reference, the International Space Station generally operates at an altitude between 205 and 270 miles.

The Orion capsule is designed to carry up to six astronauts further than we’ve ever gone before, and while it will not carry a crew Thursday, it still serves an important purpose.

The mission is meant to to test Orion’s core systems components for manned spaceflight, including the Launch Abort System, radiation shielding necessary to pass through Earth’s dangerous Van Allen radiation belt, and atmospheric re-entry systems.

As Thursday’s mission draws to an end, the spacecraft will descend at speeds up to 20,000 miles an hour before splashing down in the Pacific Ocean. Two U.S. Navy vessels will recover the capsule.

The mission, explained:

The Adler Planetarium will be hosting a free watch party from 5:30 to 11 a.m. to mark the occasion.

Naturally, NASA has pulled out all the stops on social media.