LAS VEGAS — ABL Space Systems is moving into the final phases of preparations for the second launch of its RS1 rocket after the company’s first launch failed in January.

In an update posted Oct. 25, Harry O’Hanley, chief executive of ABL, said the company has completed a test of the RS1 rocket it called “dock dress” at the Port of Long Beach in California. That was a dress rehearsal of launch preparations involving the rocket and its GS0 ground support equipment.

Both the RS1 rocket and GS0 system feature upgrades since the inaugural launch failed seconds after liftoff Jan. 10 from Kodiak Island, Alaska. The company said a week after the launch that the rocket lost power about 10 seconds after liftoff, shutting down engines and causing it to crash near the launch pad.

At the time, ABL said the loss of power was linked to a fire in the rocket’s engine compartment, but didn’t say how the fire started. O’Hanley wrote that the leading theory that emerged from the company’s investigation is that the fire is linked to the design of the launch mount, a part of the GS0 system that raises the rocket to the vertical position and lowers it back to the horizontal.

The launch mount was made to be as compact as possible to allow it and other GS0 elements to fit into shipping containers. “While this made transport simple, it resulted in the rocket being held close to the ground,” he wrote.

However, that meant there was limited space between the engines and the ground so that, at engine ignition, there was restricted flow of exhaust. “This caused plume recirculation and drove pressures and temperatures beneath the rocket to exceed the RS1 base heat shield design capability,” he wrote. Hot gases broke through the heat shield and caused the engine compartment fire.

The company has redesigned the launch mount to increase its height and exhaust area to prevent the exhaust recirculation problem. That launch mount now ships in three pieces instead of one, which he said can be assembled at the launch site in a few shifts.

O’Hanley said that the company also decided to move ahead with a Block 2 version of the RS1 rocket. That version features upgrades such as increased thrust and more propellant, as well as design changes intended to improve production.

“This strategy added significant design scope to the Flight 2 roadmap,” he wrote. “However, moving straight to Block 2 is a more direct path to building flight heritage on the configuration that will carry customer payloads to orbit.”

With the dock dress rehearsal complete, ABL is making final preparations to ship the rocket and ground support equipment to Kodiak. Once there, he said, they will go through additional tests, including a static fire of the first stage, before going forward with a launch. The company did not provide a timetable for that launch.

“It was not in our plans to have RS1 grounded for most of 2023,” O’Hanley wrote, preferring what he described as “iterative development cycles with a hardware-rich approach.”

“Circumstances pushed us in the other direction this year,” he wrote, with the company instead implementing several changes at the same time. “This prepares us well and sets a strong baseline for future RS1 and GS0 upgrade cycles.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...