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Elon Musk's SpaceX is preparing to launch the latest prototype of its next-generation Starship rocket on Wednesday, in the third high-altitude flight test of the system.
Starship prototype rocket Serial Number 10, or SN10, will aim to launch and fly as high as 10 kilometers, or about 32,800 feet in altitude. The rocket is built of stainless steel, representing the early versions of the rocket that Musk unveiled in 2019.
SpaceX fired the rocket's engines briefly for a launch attempt at about 3:15 p.m. ET but a "slightly conservative high thrust limit" caused the rocket to abort the attempt, Musk said in a tweet.
"Increasing thrust limit & recycling propellant for another flight attempt today," Musk said.
SpaceX principal integration engineer John Insprucker said on the company's webcast that it expects to make another launch attempt.
The Federal Aviation Administration's launch window for the SN10 attempt runs until 7:30 p.m. ET.
The company is developing Starship with the goal of launching cargo and people on missions to the moon and Mars.
The flight will be similar to the ones SpaceX conducted in December and February, when it test flew prototypes SN8 and SN9, respectively. Both prior rockets completed several development objectives – including testing aerodynamics, shutting down the engines in succession, and flipping to orient for landing –but both prototypes exploded on impact as they attempted to land, unable to slow down enough.
Like SN8 and SN9, the goal of the SN10 flight is not necessarily to reach the maximum altitude, but rather to test several key parts of the Starship system. The Starship prototype stands at about 150 feet tall, or about the size of a 15-story building, and is powered by three Raptor rocket engines. SpaceX will fire all three engines for liftoff and then shut them down one at a time in sequence as it nears the top of the flight's intended altitude.
SN10 will aim to transfer propellant from the main tanks to the header tanks, and then flip itself for the "belly flop" reentry maneuver so it can control its descent through the air with the rocket's four flaps. Then, in the final moments of descent, SpaceX will flip return the rocket to a vertical orientation and fire the Raptor engines to slow itself down for a landing attempt.
While SpaceX has yet to land a Starship prototype successfully after a high-altitude flight test, the company has landed previous prototypes after short flights to about 500 feet in altitude.
Starship is one of two "Manhattan Projects" that SpaceX is simultaneously developing, with the other being its Starlink satellite internet program. Musk has previously estimated that it will cost about $5 billion to fully develop Starship, although SpaceX has not disclosed how much it has spent on the program to date.
The company last month brought in $850 million in its latest capital fundraise at a $74 billion valuation.
Musk remains "highly confident" that Starship "will be safe enough for human transport by 2023" – an ambitious goal given the company began the rocket's development and testing in earnest in early 2019.
But Musk's timeline is key, as Japanese billionaire Yusaku Maezawa has paid for a Starship flight around the moon by 2023. Maezawa on Tuesday announced that he is inviting eight members of the public to join his dearMoon mission, which will be a six-day journey to the moon and back.
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