Early on Monday, Elon Musk’s SpaceX finished up final preparations for the brief but much anticipated uncrewed test flight from the Texas Gulf Coast that would be the first use of its potent new Starship rocket system in orbit.

The two-stage rocketship, which is 394 feet (120 meters) tall and taller than the Statue of Liberty, was scheduled to launch from the SpaceX site in Boca Chica, Texas, during a two-hour window that begins at 8 a.m. EDT (1200 GMT).

Whether or not the test mission’s goals are fully achieved, it still marks a significant step toward SpaceX’s ultimate aim of returning people to the moon and eventually Mars. This is also the main purpose of a revitalized NASA spaceflight program designed to incorporate the Starship.

The best-case scenario, according to Musk, would reveal important information about how the spacecraft ascends to space and how it would fly back to Earth. “Success is not what should be expected,” Musk said to a private Twitter audience on Sunday night.

Tomorrow probably won’t go well, he said. “It’s just fundamentally a very difficult thing.”

The California-based corporation earlier on Sunday posted on Twitter that its launch crews were continuing with flight preparations while closely monitoring any potential wind-shear conditions in the forecast that might cause a delay.

For the aircraft to be delayed rather than take off on Monday, according to Musk, “it’s more likely” on Sunday night. On Tuesday and Wednesday, SpaceX has backup launch opportunities for roughly the same times.

Similar to a meteor
Both the lower-stage Super Heavy booster rocket and the upper-stage Starship cruise ship it will launch into orbit are intended to be reusable parts that may return to Earth for gentle landings, as SpaceX’s smaller Falcon 9 rocket has done repeatedly.

For the disposable first test voyage to space, which should last no longer than 90 minutes, neither stage will be recovered.

The Super Heavy booster has never left the ground, despite five sub-space flights by Starship cruise vessel prototypes up to 6 miles (10 km) above Earth in recent years.

Just last Friday, the Federal Aviation Administration approved a license for the fully stacked rocket system’s first test flight, removing the last remaining legal barrier to the eagerly anticipated launch.

If everything goes according to plan on Monday, all 33 Raptor engines will fire at once to launch the Starship on a flight that nearly completes a full orbit of the Earth before it re-enters the atmosphere and free-falls into the Pacific at supersonic speed off the northern Hawaiian islands, about 60 miles (97 km) away.

The Super Heavy booster is anticipated to carry out the initial stages of a controlled return flight after detaching from the Starship before crashing into the Gulf of Mexico.

The starship’s scorching re-entry over the Pacific will test its capacity to guide itself aerodynamically using massive flaps and for its heat shielding to endure the high friction created as it falls into the atmosphere.

According to Musk, “the ship will be coming in like a meteor.” This is the opening leg of a protracted journey that will involve numerous planes.

He noted that other Super Heavy boosters were waiting on the dock in Boca Chica for upcoming test flights.

As intended, the Starship rocket has roughly twice the power of NASA’s own Space Launch System (SLS), which launched a NASA cruise ship dubbed Orion on its first unmanned flight to orbit in November and completed a 10-day trip around the moon and back.