SpaceX’s Starship is set to launch on its fifth test flight later as Elon Musk presses ahead with his quest to build the most powerful rocket system in history.

For the first time, SpaceX will attempt to catch the Super Heavy carrier located at the bottom of the two-stage vehicle as it returns to the launch pad in Texas.

Safe landing of the launch vehicle increases its chances of rapid reusability, which would reduce the cost of space travel.

Until Saturday, it was unclear whether the launch would even take place as SpaceX waited for approval from US authorities.

Last month SpaceX publicly accused that the U.S. government was jeopardizing “America’s position as a leader in space” by taking the time to review its records on key issues such as the environmental impact of the flight.

A fifth flight in just 18 months is an extraordinary achievement for the SpaceX team. On the first two flights, the vehicle was blown up shortly before its missions.

However, SpaceX argues that this is all part of its development plan – an early start in anticipation of failure so that the company can collect as much data as possible and develop its systems faster than its competitors.

Since the last flight in JuneSpaceX says its engineers collectively worked 12,000 hours to replace Starship’s entire heat shield with additional protection. During its final flight, as it re-entered Earth’s atmosphere, some of the protective tiles on the surface were destroyed as the ship was surrounded by superheated, ionized gas.

This time, SpaceX hopes to launch the 400-foot (121 m) system, but instead of leaving the entire system submerged in the Indian Ocean like the last flight, the Super Heavy is scheduled to fly back to the launch pad, where it can be caught between one and a pair of giant rockets mechanical arms called “chopsticks”.

The initial stages of the ascent will be the same as the previous four excursions, with ship and launch vehicle separating two and three-quarter minutes after leaving the ground.

But then the booster will fly back to the launch site in Boca Chica, Texas, and fire up its engines again to slow the vehicle from supersonic speeds. Sonic booms can be expected in the area.

The launch pad features the world’s tallest rocket tower, standing at 480 feet (146 m) tall and featuring two giant robotic arms. These will collect the rocket booster before stacking it back on the orbital launch cradle for its next flight.

Catching the launch vehicle instead of landing it on the launch pad reduces the need for complex hardware on the ground and allows for rapid redeployment of the vehicle in the future.

If the flight director does not believe this is possible, a call to land the booster in the Indian Ocean will be made before the boostback burn – when the rocket turns around. This will be less than three minutes into the flight.

Elon Musk and SpaceX have big plans for the rocket system to one day take humanity to Mars and make our species “multiplanetary.”

The US space agency NASA will closely monitor the flight test. It has paid the company $2.8 billion (£2.14 billion) to develop Starship into a lander capable of returning astronauts to the lunar surface by 2026.

From a space engineering perspective, that’s not that far away, so Elon Musk’s team was eager to get the rocket launched again as quickly as possible.

But the Federal Aviation Administration (FAA), the U.S. government agency that must approve the flight, had previously said there would be no launch before November as it reviewed the company’s approvals.

The agency and Elon Musk have been in a public spat since last month after the FAA said it planned to fine his company SpaceX $633,000 for allegedly failing to comply with its license terms and obtain permits for previous flights .

Before issuing a license, the FAA examines the impact of the flight, particularly the impact on the environment.

In response to the fine, Musk threatened to sue the agency and SpaceX filed a lawsuit public blog post They defend themselves against the “false report” that part of the rocket pollutes the environment.

Currently, the FAA only considers the impact of rocket launches on the immediate environment and not the broader impacts of emissions.

Dr. Eloise Marais, a professor of atmospheric chemistry and air quality at University College London, said carbon emissions from rockets pale in comparison to other forms of transport, but there are other planet-warming pollutants that are not taken into account.

“Black carbon is one of the biggest problems. The Starship rockets use liquid methane. It’s a relatively new fuel and we don’t have very good data on the amount of emissions coming from liquid methane,” she said.

Dr. Marais said the black carbon from rockets is so concerning because it is released hundreds of kilometers higher into the atmosphere than aircraft.

“They introduce pollutants into layers of the atmosphere where they stay for two and a half or three years, compared to pollutants near the Earth’s surface, which disappear after about a few days to a week. “So the longer they stay in the atmosphere, the greater their impact,” she said.

In April, NASA released its first space sustainability strategy, which said: “The chemicals used in launch raise concerns about atmospheric impacts.” It did not propose specific solutions but committed to working with its climate team on the problem.