SANTA FE, N.M. – SpaceX general director Elon Musk says the redesigned test vehicle for the next-generation reusable launch system may be ready for the first flights early next year.
In a tweet early on December 24, Musk posted a photo of two parts of this preliminary test article, a conical section next to a cylindrical unit with landing legs. "Stainless steel ship" – he wrote.
Stainless steel ship pic.twitter.com/rRoiEKKrYc
– Elon Musk (@elonmusk) December 24, 2018
Spaceship is a new name, announced last month by Musk, on the higher or "cosmic" stage of the next generation launch system, officially known as Big Falcon Rocket, or BFR. The lower gain stage is now called "Super Heavy".
The company is working on a test article for a space ship for trial flights at low altitude in the South Texas factory site. This test article, known as "funnel" it would have the same nine-meter diameter as a full-size vehicle vehiclebut it would not be so high.
The company filed an application with the Federal Communications Commission on November 19, applying for an experimental license to support communication with the funnel during the upcoming flights. SpaceX said it plans to combine flights at low altitudes that do not exceed 500 meters, and flights at altitudes up to 5,000 meters from Texas. The company did not disclose the flight schedule in the application, but stated that it needs a license for two years.
Musk and other company representatives said that these planes will take place at the end of 2019. However, Musk wrote on Twitter on December 22 that he expected flights to start early next year. "I will do a full technical presentation of the spacecraft after the test vehicle we are building in Texas, so let's hope March / April" he wrote.
The latest series of tweets from Musk also confirmed the change of materials that will be used to build the vehicle. Original plans, derived from projects presented in 2016 and 2017, required the use of carbon composite materials that are lightweight but have high strength. Earlier this month, Musk said that SpaceX turned to "quite heavy metal" for use in a vehicle.
This metal, he said, is a stainless steel, in particular the alloy family called the 300 Series, known for maintaining its strength at high temperatures. Although they are heavier than carbon composites, Musk said that stainless steel offers "slightly better" resistance to weight at cryogenic temperatures, needed for liquid oxygen fuel tanks in the vehicle and was "much better" at high temperatures. He admitted that the steel is worse than the carbon composite at room temperature.
He added that the surface of a stainless steel vehicle would require "much less" thermal protection, but it would also not be painted. "Skin will be too hot for paint" he wrote on Twitter. "Stainless mirror finish, maximum reflectivity."
The test site will be powered by three of the company's RAPPOR Methane / Liquid Oxygen engines as part of the development. These engines, over which the company has been working for several years with some financial support from the US air force, have also undergone changes in the project. "Radically redesigned Raptor ready to fire next month" he wrote on Twitterwithout discussing these changes.
He noted that SpaceX had developed a "superalloy" for the Raptor, called the SX500, designed to handle hot oxygen-rich gas at pressures up to 12,000 pounds per square inch. "Almost every metal turns into a flame under these conditions" he wroteby adding this The foundry of the company producing this alloy is "almost fully operational". This foundry "allows for quick iteration on the Rapper."