SpaceX has completed the fourth test of its revolutionary modern Starship rocket, a key step toward returning humans to the Moon and perhaps one day landing on Mars.
The flight, Integrated Test Flight 4, lifted off today from SpaceX’s Boca Chica Test Site in Texas at 7:50 a.m. central time. The 71-meter (233-foot) rocket and its 33 methane-fueled Raptor engines roared to life, lifting Starship – the largest rocket in history – into the sky over the Gulf of Mexico from a test site called Starbase.
“Today’s test was the clearest success to date,” says Abhi Tripathi, former mission director at SpaceX and now an aerospace engineer at the Space Science Laboratory at the University of California, Berkeley. “It was amazing.”
Although one of the engines failed (Starship was designed for redundancy in the event of an engine failure), the rocket’s journey into space went smoothly. This was the third time a spacecraft had reached space and the second time it had reached suborbit; the second was the final test flight of IFT-3 in March.
The Starship consists of two parts, a lower part called the Super Bulky Booster, and an upper part, the Starship itself, which will one day accommodate up to 100 people on expeditions to the Moon and Mars. Three minutes into today’s flight, at an altitude of approximately 78 kilometers, the two sections separated as planned, and Super Bulky began its journey back to Earth.
Once Starship is fully operational, the goal of each super-heavy booster (and spacecraft) will be to land back at the launch site, where they will be caught by giant “sticks” on the launch tower, ready for their next flight. But before SpaceX can do that, it wants to prove that the Super Bulky can safely return to Earth. So one of the key goals of today’s test was to descend the booster toward the Gulf of Mexico, re-ignite the 13 engines and gently splash down.
This test passed flawlessly for the first time, and the booster melted seven and a half minutes into the mission. “The landing of the booster rocket in the ocean was phenomenal,” says Laura Forczyk, space consultant and founder of George-based Astralytical. “This gives us confidence that SpaceX can make Starship reusable.”
Starship continued its journey into space, with the vehicle flying over the Atlantic Ocean, southern Africa and into the Indian Ocean, reaching a maximum altitude of 250 km – half the height of the International Space Station’s orbit – after approximately 24 minutes of flight.
From here it then began its own journey back into Earth’s atmosphere, also attempting to make a vertical test landing in the ocean. This task, however, is much more hard for Starship; Driving at a speed of about 30,000 km/h, the vehicle must face temperatures of up to 2,600 degrees Fahrenheit (1,400 degrees Celsius) when it hits the atmosphere.
The underside of the spacecraft is covered with heating plates to displace this heat, but during Starship’s last test flight in March, the craft disintegrated at an altitude of about 60 km due to the intensity of re-entry. This time, SpaceX hoped to make it all the way to the ocean by removing two plates to see how the vehicle itself copes with high temperatures.