SANTA FE, NM – SpaceX's CEO Elon Musk says a new test vehicle for the company's next-generation reusable launch system could be ready for first flights early next year.
In a tweet early December 24, Musk sent a picture of two parts of the first test article, a tapered part next to a cylindrical unit with the landing leg. "Stainless Steel Starship," he wrote.
Stainless Steel Starship pic.twitter.com/rRoiEKKrYc
– Elon Musk (@elonmusk) December 24, 2018
Starship is the new name announced by Musk in the previous month, of the upper or "spaceship" of the next generation launch system, formerly known as Big Falcon Rocket, or BFR. The lower booster scene is now called "Super Heavy."
The company has been working on a low-level Starship test article for the company's South Texas launch site under development. This test article, called a "hopper", would have the same diameter of nine feet as the full-scale vehicle but would not be so high.
The company filed an application with the Federal Communications Commission on November 1
Musk and other company employees have said that these jumpers will begin in late 2019. But Musk tweeted Dec. 22 that he expected the planes to start as early as next year. "I want to do a full technical presentation of Starship after the test vehicle we build in Texas flies, so hopefully March / April," he wrote .
The latest series of tweets from Musk also confirmed A change in materials that will be used to build the car. Initial plans, which date back to the designs presented in 2016 and 2017, required the use of lightweight, high strength carbon composite materials. Earlier this month, Musk said SpaceX had moved to a "rather heavy metal" for use in the vehicle.
That metal, he said, is stainless steel, especially a series of alloys called the 300 series known to maintain its strength at high temperatures. Despite being heavier than carbon composites, Musk said that stainless steel offered "slightly better" strength to cryogenic temperature performance needed for the car's liquid oxygen fuel tanks, and was "far better" at high temperatures . He acknowledged that steel was worse than carbon composite at room temperature.
A stainless steel surface in the vehicle, he added, would require "much less" thermal protection, but would not be painted either. "Skin gets too hot for paint," he tweeted . "Stainless mirror finish. Maximum reflectivity."
The test tank will be powered by three of the company's Raptor methane / liquid-oxygen engines during development. The engines that the company has been working on for years with financial support from the US Air Force have also undergone design changes. "Radically redesigned Raptor ready for fire next month," he tweeted not elaborated on these changes.
He noted that SpaceX had developed a "superalloy" for Raptor, called the SX500, designed to handle hot oxygen rich gas at pressures up to 12,000 pounds per square inch. "Almost any metal becomes a flare under these conditions," he wrote and added that the company's foundry to produce that alloy is "almost fully operational." The foundry "allows rapid iteration on Raptor."