Elon Musk is on a roll this week. Sunday afternoon, Musk tweeted a short video of a test on the hexagonal heatshield tiles that will eventually protect the Starship from burning up on reentry into Earth’s atmosphere.
In the video, blowtorch-like devices heated up the hexagonal tiles to a maximum temperature of around 1650 Kelvin (approx. 2,500 degrees Fahrenheit, approx. 1,375 degrees Celsius). Musk explained that hexagonal tiles were used because they provide “no straight path for hot gas to accelerate through the gaps.”
Testing Starship heatshield hex tiles PycE9VthxQ
— Elon Musk (@elonmusk) March 17, 2019
Musk suggested that the tiles could withstand the extreme temperatures created on re-entry, although NASA’s Space Shuttles were built to withstand slightly higher temperatures (approx. 1,500 degrees Celsius). SpaceX plans to install the tiles on the “windward” side of the Starship, towards the direction of re-entry, “with no shielded need on the leeward side,” according to Engadget.
SpaceX will use something called a “transpiration cooling” system. The heat shield tiles will have microscopic pores on the outside that allow water or methane to ooze out and cool the exterior. This should minimize damage to the tiles and allow the starship to return to service after refilling the heatshield reservoir.
“Transpiration cooling will be added wherever we see erosion of the shield,” tweeted Musk. “Starship needs to be ready to fly again immediately after landing. Zero refurbishments.” Now, how cool is that?
Along the same train of thought, “aspiring space kid” Austin Barnard spotted the Raptor rocket engine on March 12, in Boca Chica, Texas, where SpaceX is gearing up for Starship’s first test “hops”. Even more intriguing, on March 16, Austin tweeted photos of the Raptor engine affixed to the Starhopper for the first time.
After a day worth of hard work, the workers at SpaceX have finally installed the first raptor on StarHopper . Congratulations to Elon musk and all the hard workers at SpaceX. It’s almost time for StarHopper to purr like a kitten . YIhbNhqJEk
— Austin Barnard (@austinbarnard45) March 16, 2019
This has led to speculation that SpaceX intends to test the “Hopper” out for the first time in a day or two. Actually, Business Insider is reporting that SpaceX may be firing up its “Test Hopper” prototype as soon as Monday, according to a notice stuffed into the mailboxes of some residents near Boca Chica Beach, which is at the southernmost tip of Texas.
