SpaceX is gearing up to launch the newest version of its Starship megarocket—a vital prototype for NASA’s mission to send astronauts to the moon within two years—in a pivotal test flight this Tuesday.

The stakes for Starship and Elon Musk’s SpaceX are at an all-time high. As part of NASA’s Artemis program, SpaceX is vying with Jeff Bezos’ Blue Origin to create a lunar lander, aiming to get astronauts to the moon by 2028. NASA plans to test one or both systems during the Artemis III mission next year in low Earth orbit.

Simultaneously, SpaceX is on the cusp of going public. The anticipated IPO next month could potentially be the largest in history. As reported by Reuters, a prospectus is expected to be released shortly after the Starship test flight, with a market debut likely by mid-June.

Starship has experienced a series of challenges during previous test flights, including an uncontrolled re-entry and two mid-flight explosions last year as the upper spacecraft ascended.

The last Starship test flight occurred seven months ago. Since then, significant redesigns have taken place for both the booster, Super Heavy, and the upper stage, known as Ship. This next launch marks the inaugural test flight of SpaceX’s third-generation Starship, termed V3. Taller and more powerful, Starship V3 stands at 408 feet when fully stacked, surpassing its predecessor.

It will launch from a new pad at SpaceX’s Starbase facility in southern Texas during the 6:30 p.m. ET launch window.

The flight plan resembles earlier Starship missions. According to SpaceX, during this suborbital test flight, Starship aims to deploy 22 mock Starlink satellites and reignite one of its six Raptor engines while in space—a crucial demonstration for future deorbit maneuvers when returning from space.

Tuesday’s mission is projected to last around 65 minutes. If successful, the upper stage is set to splash down in the Indian Ocean. SpaceX ultimately aims for Starship to be reusable, employing a mechanical arm to catch the spacecraft on a launch tower at the Starbase facility in Texas.

SpaceX previously demonstrated a similar catch technique with the Starship’s Super Heavy booster during an earlier test flight. In contrast, the booster scheduled for Tuesday will land in the Gulf of Mexico, without attempting to return to the launch site.As per SpaceX.

However, Starship’s development is trailing behind NASA’s expectations. Initially expected to fly in 2023, setbacks in the last year have pushed back timelines. NASA had aimed to land astronauts during the Artemis III mission but revised those plans earlier this year to allow for more time to develop lunar landers.

NASA Administrator Jared Isaacman indicated in testimony last month that Artemis III would launch in late 2027, rather than mid-2027 as initially proposed.

SpaceX is under tight deadlines as it prepares Starship for next year’s Artemis III mission. This mission will call for the Starship upper stage to rendezvous with NASA’s Orion capsule, which recently orbited the moon with Artemis II astronauts. SpaceX needs to ensure Starship is qualified for crewed lunar flights next year.

Plans for the Artemis IV mission in 2028 include Starship’s upper stage orbiting the moon and docking with Orion to transfer astronauts to the lunar surface, ultimately returning them to Earth.

Updates to Starship for V3 encompass new Raptor 3 engines for both Super Heavy and Ship, capable of generating around 18 million pounds of thrust.

Additionally, SpaceX has enhanced the propellant tank volume and reduced the number of grid fins on the booster to improve landing precision.

“These advancements aim to unlock Starship’s core functions, including rapid reusability, propellant transfer in space, Starlink satellite deployment, and facilitating human and cargo transport to the Moon and Mars,” SpaceX stated on its website.

Successful propellant transfer in space is essential for enabling the upper stage to refuel in orbit before heading to the moon. A successful test flight on Tuesday could pave the way for these critical future operations.