Updated April 20, 2023 at 8:35 AM ET
SpaceX will try to launch its massive mega-rocket Starship again on Thursday after it was delayed earlier this week due to a frozen valve.
The launch window will begin at 9:28 a.m. ET in south Texas and last for 62 minutes. If successful, the stainless-steel spaceship will fly around the earth for roughly five hours before splashing down near Hawaii.
"All systems currently green for launch," SpaceX CEO Elon Musk said in a tweet early Thursday.
Musk has billed the world's largest rocket as a way to transport humans to the moon and Mars. It could also be a workhorse for transporting Starlink satellites, a key revenue-maker for the company.
Monday's intended launch was called off just minutes before the scheduled liftoff due to a frozen valve. The issue occurred in the spacecraft's super-heavy booster, which uses 33 engines working in synchronicity to lift the 400-foot-tall rocket off the ground.
The decision to use such a large number of engines — more than any other rocket ever made — is a trade-off, says Paulo Lozano, director of MIT's space propulsion laboratory.
Though it's necessary for lifting big payloads, "having that large number of rocket engines firing simultaneously — it's actually quite hard. I think that's going to be one of the biggest challenges," Lozano said.
Adding to the challenges is the choice of fuel: methane. SpaceX wants to experiment with methane because it's cheaper to produce and easier to handle than hydrogen, the go-to fuel choice for most high-powered rockets.
But methane and the rocket's oxidizer oxygen need to be chilled to very low temperatures in order to operate, which may explain the frozen valve.
SpaceX seems to understand the risks associated with such a monumental test launch. It's blown up quite a few rockets during testing in the past, a development strategy that's worked well in the long-term.
"With a test such as this, success is measured by how much we can learn," the company said in a statement following Monday's scrubbed mission.
Copyright 2023 NPR. To see more, visit https://www.npr.org. 9(MDAwMTM1NDgzMDEyMzg2MDcwMzJjODJiYQ004))