Relativity postpones Florida launch of 3D-printed Terran rocket

March 8 (Reuters) - California-based startup Relativity Space called off the planned debut launch of its 3D-printed rocket in Florida on Wednesday over fuel temperature concerns, delaying a key test of the company's novel strategy for cutting manufacturing costs.

The 110-foot-tall (35-meter) Terran 1 rocket, 85% of which was fabricated from a 3D-printer, had been scheduled to lift off from a U.S. Space Force Base launch pad in Cape Canaveral on Wednesday afternoon. Dwindling "propellant thermal conditions" in the rocket's second stage during a three-hour launch window ultimately forced a scrub, the company said on Twitter.

The company said the rocket's next launch attempt is scheduled for Saturday in a window from 1 p.m. to 4 p.m. EST (1800 to 2100 GMT).

Relativity, one of a handful of U.S. rocket startups competing to meet the growing demand for cheap launch services, has bet on the cost savings it expects to achieve using giant, robotic 3D-printers to simplify its rocket production lines.

Most of its rivals have focused on lowering costs by building rockets designed to be reuseable, such as the Falcon 9 boosters produced by Elon Musk's SpaceX.

The inaugural Terran 1 launch is intended to validate the company's supposition that its rocket's 3D-printed structure can withstand the forces of a launch off Earth.

"The launch that we're preparing for is an opportunity to demonstrate a whole bunch of things all at once," Josh Brost, Relativity's senior vice president of revenue, told Reuters ahead of the planned launch attempt.

Brost called the Terran 1 "by far the largest 3D-printed structure that's ever been assembled."

The 3D-printing process, widely used in various industries, involves machines that autonomously "print" sequential layers of soft, liquid or powdered materials that are quickly hardened or fused to form solid, three-dimensional objects. Designs of the objects are scanned from digital blueprints.

The use of 3D-printers, Brost said, allows Relativity to hasten much of its manufacturing processes and more easily make changes to improve the rocket's design if needed after it flies, eliminating the need for a complex supply chain that would otherwise slow down rocket enhancements.

"First launches of new rockets are notoriously prone to have different reasons that they need the scrub," Brost said. "So it would not be at all unlikely for us to even need a couple of attempts to get through the countdown and lift off for our inaugural launch."

While the expendable Terran 1 is built to carry 2,755 pounds (1,250 kg) of satellites to low-Earth orbit, waning demand for that class of launch vehicle has led Relativity to develop a larger, 3D-printed reusable rocket - the Terran R - that it expects to fly in 2024.

Currently driving demand are the so-called mega-constellation plans by companies such as SpaceX, OneWeb and Jeff Bezos' Amazon (AMZN.O) to deploy tens of thousands of internet-beaming satellites to low-Earth orbit in the next few years.

SpaceX flies its own heavy-lift rockets to get its Starlink network into orbit, while Amazon and OneWeb plan to use similar large rockets from various launch companies for their own satellites. OneWeb will launch its next-generation satellites on Relativity's Terran R, the companies announced last year.

Relativity has roughly $1.65 billion worth of launch contracts secured for both its rockets, with the bulk of that revenue attributable to the larger Terran R.

While market demand for rockets like Terran 1 has weakened, Brost said the rocket's upcoming flights will inform how Terran R is engineered.

Asked if Relativity is still selling Terran 1 to customers, Brost said the company "continues to talk to people about both vehicles."

Reporting by Joey Roulette in Washington; Editing by Steve Gorman, Edwina Gibbs and Jamie Freed

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