SpaceX’s Starship Completes Wet Dress Rehearsal

SpaceX’s Starship launch vehicle completed its much anticipated Wet Dress Rehearsal test this afternoon. This test marks one of the last milestones left in the testing campaign for Starship. With only a few hurdles left between now and the maiden flight, we are within grasp of the Orbital Flight Test.

What is Starship?

First announced in 2016, the “Interplanetary Transportation System”, an early nickname for the Starship project, was announced at the International Aerospace Conference. In 2018, the ITS idea was morphed into a smaller scaled project, the BFR. The modern Starship design took shape in 2019, with early test demonstrators being constructed originally in Florida, and later Boca Chica, Texas. All three concepts had the same core concept, to enable fully reusable, cheap, and accessible access to not just space, but Mars.

From the first sight of a small test demonstrator in the southern tip of Texas, the Starship program began to take shape. Slowly but steadily growing into one of the largest research and development complexes in the world, “Starbase” has become the hub of SpaceX’s future. 

In its modern form, the Starship design consists of two major elements. Firstly; The Super Heavy booster is the backbone of the program. 

Developed out of stainless steel, Super Heavy is one of the most powerful rocket stages ever developed, with 33 raptor engines mounted on the booster. The booster is able to be fully recovered, being able to fly back to the launchsite after stage separation and be caught and placed back onto the launch pad only minutes after liftoff.

The Starship upper stage is one of the most unique rocket stages to be flying, and is the first fully reusable second stage of a rocket ever developed. Made of stainless steel and six raptor engines, the starship upper stage is tuned to operation in the vacuum of space. After deploying a payload, the upper stage is able to then reenter into space by using its array of heat shield tiles. These tiles are able to absorb the heat and forces of reentry.

The Starship Super Heavy rocket is both taller and more powerful than NASA’s Saturn V and SLS vehicles, and will allow a new access to space that has never been seen before. Combined, both vehicles have undergone a rigorous testing campaign over the past year, and are closely approaching their first launch attempt.

Starship upper stage being stacked on the Super Heavy Booster

Milestone: Wet Dress Rehearsal

On January 23, Starship completed a ‘Wet Dress Rehearsal’. Wet Dress Rehearsals (WDRs) are a very common structural test for rockets, and help to test the rocket’s fuel loading procedures, along with ironing the launch timeline and schedule.

A WDR is a simulated launch, and goes through the traditional launch process for the vehicle. The test includes filling up the propellant takes to operational levels, preparing the rocket engines, and conducting necessary ground and infrastructure procedures. A WDR verifies all aspects of the launch sequence except the ignition of the rocket engines and the release of the holding clamps.

This test not only verifies that the rocket is ready to launch, but also prepares the launch teams for the launch process. Now that both the teams and rocket have verified the launch sequence, final tests can be conducted leading up to the inaugural launch.

Moving Forward

As Starship and the Starbase launch site move on to its final tests, there are only a handful of obstacles left in the way of the Orbital Flight Test. The two major milestones remaining are the much anticipated 33 engine static fire, and the FAA Launch License. 

Starting with the boring of the two, the FAA Launch License is the regulatory approval to launch a rocket into space. The license is needed for every rocket launch, and it is the last remaining regulatory approval before the OFT. The Launch License is expected to be approved shortly after the 33 engine static fire, which will signal the end of testing and the beginning of launch attempts. 

The 33 engine static fire is shaping up to be the last test for Booster 7 and the combined vehicles. The static fire consists of igniting all 33 engines on the booster stage, testing the capability of each engine to achieve flight-level performance. The static fire will likely not ignite all engines simultaneously, and will instead stagger out the ignitions of individual or groups of engines to lower the force load on the vehicle, launch mount, and ground infrastructure. 

Before attempting the static fire, the Starship upper stage will need to be ‘de-stacked’ from the booster stage, before being transported to the far side of the launch site. This is done to protect the upper stage from possible damage incurred from the static fire. Engineers and Technicians will then flood the launch mount to repair, tune, and check every part of the booster and launch mount. Because of the sheer force of the static fire test, even small issues can cause extreme damage to the vehicle and surrounding equipment. After the site has been sufficiently checked out, the launch site will be cleared out of all personnel and equipment.

Orbital Flight

As of now, there is no official date for the inaugural launch attempt for Starship.