A test of the Super Heavy Booster for Starship’s fifth test flight
SpaceX
SpaceX is making final preparations for the fifth and most ambitious Starship test flight yet. While the four previous flights have all aimed for a splashdown in the sea, this test will be the first attempt to land back on the launch pad.
What is Starship?
It is the heaviest and most powerful rocket that has ever flown. SpaceX aims to develop it into a rapidly reusable launch vehicle that can take large payloads to space, land back at the launch pad and be ready for another mission within days or even hours. Successive test flights over the past two years have been inching towards that goal.
NASA has contracted SpaceX to supply a special lunar lander variant of Starship to take astronauts to the moon’s surface some time after late 2026. The ultimate ambition of SpaceX CEO Elon Musk is for Starship is to put humans on Mars.
What will SpaceX attempt during its fifth test flight?
Flight five is likely to be the first attempt at catching Starship’s Super Heavy booster – the first stage of the rocket – on the launch pad. SpaceX’s launch tower, called Mechazilla, is equipped with a pair of “chopsticks” that will ultimately grab the booster at a specific point and secure it, allowing it to be later lowered the remaining distance to the ground.
The fourth test flight saw the booster make a “virtual landing” at sea, slowing its descent just above the surface to simulate what would be needed for a real Mechazilla catch, before it plopped into the water. Following the success of that test, Musk posted on X that “I think we should try to catch the booster with the Mechazilla arms next flight”.
When is the launch expected to happen?
We don’t yet have an official launch date, but a full-duration test burn of the rocket’s first stage was carried out on 15 July, meaning that there is little now standing in the way.
Musk himself said in an X post on 6 July that the launch would happen in “4 weeks” – placing it provisionally on or around 3 August. But it is worth bearing in mind that Musk has a history of making claims about delivery that aren’t met.
What happened during previous Starship launches?
Test flight 1 on 20 April 2023 saw three of the first stage’s 33 engines fail to ignite. Several more subsequently failed during the flight. The rocket then spun out of control, causing its self-destruct feature to kick in.
Test flight 2 on 18 November of the same year got further, gaining enough altitude that the first and second stages separated as planned. But as the first stage rotated to begin its slowdown and landing procedure, it exploded. The second stage successfully continued to an altitude of about 149 kilometres, passing the Kármán line that marks the beginning of space. However, a safeguard feature destroyed it when it stopped sending data, before it had a chance to complete an orbit or make its way back to Earth.
Test flight 3 on 14 March of this year was at least a partial success as it reached space, carried out fuel transfer tests and travelled further and faster than ever before. But the craft failed to make its scheduled soft landing after losing attitude control mid-flight.
Test flight 4 on 6 June of this year was the most successful so far, with Starship reaching orbit at an altitude of over 200 kilometres and travelling at more than 27,000 kilometres per hour. Both the booster and upper stage completed soft splashdowns in the ocean. There were dramatic scenes as Starship re-entered Earth’s orbit, as the vast temperatures caused the skin of one of its control fins to burn away – something the company says it has fixed with new heat-resistant tile designs.
What happens if this launch goes wrong?
It probably will go wrong, in some respect, as Starship is highly unlikely to complete its mission flawlessly. But any failure will supply data and experience that can be used to improve the design and processes for the sixth launch. SpaceX has shown that it can iterate rapidly and make significant progress with every launch.
Still, the company’s bold strategy to catch the booster on the launch pad will put not only the craft but also ground hardware at risk. That means the fifth test flight is perhaps the riskiest to date.