“Godspeed Artemis”, Elon Musk wrote on social media Sunday, wishing luck to NASA’s Artemis I. The moon rocket is scheduled to take off on August 29 at 8:33 AM EST, or 6:03 IST. Musk was responding to a NASA post that clarified that Artemis had a two-hour launch window.

The Artemis I is using the Space Launch System rocket built by NASA, which has now bested SpaceX’s Falcon Heavy post-launch rocket for the heaviest space rocket. However, the crown may soon return to Musk’s SpaceX soon if the Starship mission is successful.

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The first launch of NASA’s Artemis will not carry any humans, like most of Elon Musk’s rockets. It is poised to send an empty crew capsule into lunar orbit, a half-century after NASA’s Apollo program, which landed 12 astronauts on the moon.

While Elon Musk wished luck to NASA for the upcoming launch, other aerospace organisations have largely stayed mum. Virgin Group founder Richard Branson and Blue Origin boss Jeff Bezos have not publicly commented on the mission.

Astronauts could return to the moon in a few years, if this six-week test flight goes well. NASA officials caution, however, that the risks are high and the flight could be cut short.

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In lieu of astronauts, three test dummies are strapped into the Orion capsule to measure vibration, acceleration and radiation, one of the biggest hazards to humans in deep space. The capsule alone has more than 1,000 sensors.

The follow-on Artemis flight, as early as 2024, would see four astronauts flying around the moon. A landing could follow in 2025. NASA is targeting the moon’s unexplored south pole, where permanently shadowed craters are believed to hold ice that could be used by future crews.