ABL Closes Investigation Ahead of the Second RS1 Launch

Nearly ten months after the failed first launch, an internal investigation, and a lot of behind-the-scenes work, ABL seems back on track. Recently, the American company announced that the investigation, supervised by the FAA, is now completed and 22 corrective actions are being implemented ahead of the second RS1 launch. Important updates on the RS1 development were also reported by Harry O’Hanley, CEO of ABL in a Blog post.

RS1 and GS0 on the launch pad. Credits. ABL — *RS1 and GS0 on the launch pad. Credits: ABL*

ABL Space Systems is developing a low-cost small launch vehicle and a compact transportable ground system (GS0) to enable fast launches from any flat pad globally.

Maiden launch and investigation

On January 10, 2023, 5 years after the establishment of the company, at 23.27 UTC, the first RS1 rocket lifted off from the Pacific Spaceport Complex, on Kodiak Island, Alaska. The rocket successfully cleared the small launch pad, but only a few seconds after liftoff it lost power and fell on the launch pad. The payload consisted of two Cubesats, VariSat 1A and 1B, for Omniteq.

ABL's RS1 rocket lifting off during Flight 1. Credits: ABL — *ABL’s RS1 rocket lifting off during Flight 1. Credits: ABL*

The investigation, opened the following day, established that the anomaly was caused by a fire started in the first stages’ aft end. In particular, the launch mount, found to be inadequate, caused an excessive heat and pressure concentration under the rocket. Far more than the originally designed heat shield’s capability.

10:87 seconds after liftoff the hot combustion gasses breached inside the engine compartment, triggering a fire. The flames then burned some wire harnesses, causing the loss of power and the simultaneous shutdown of all nine E2 engines.

To achieve a more complete perspective of the failure and better evaluate the best upgrades, ABL also convened an External Independent Review Board (EIRB). The EIRB provided an important contribution to the redesign of the GS0.

Toward next launch

During this year the ABL team apported major upgrades to its system and conducted several tests toward the second launch.

Even if a second RS1 Block 1 rocket was already made, the company decided to move directly to Block 2 for the second flight. With RS1 Block 2 significant improvements have been achieved.

RS1 Block 2 and Block 1. Credits: Harry O'Hanley — *RS1 Block 2 and Block 1. Credits: Harry O’Hanley*

The new Boost E2 engines enable a faster integration time, speeding up production. In addition to the nine radially arranged engines, a double barrel center engine was added. A detachable Stage 1 aft end was implemented. According to O’Hanley, the Block 2 rocket will have a 20% higher thrust and a 20% higher propellant capacity.

To prevent further plume recirculation the height, width, and exhaust area of the launch mount were increased. The v2 pad was also redesigned to be shipped in three different pieces, instead of a unique one. Last summer GS0 underwent an intense series of tests and a Dock Dress was conducted.

Dock Dress Rehearsal pic.twitter.com/N0MQtzco21
— ABL (@ablspacesystems) October 25, 2023

Both the second stage and the fairings underwent extensive testing. A Hardware-in-the-Loop (HITL) testbed was built to check, verify, and improve the software systems.

The new RS1 and GS0 will now be shipped to Kodiak where further checkouts and a static fire will be conducted before the second launch. A possible schedule for the liftoff hasn’t been announced yet.

“Our efforts this year were far away from the pad lights. […] I’m proud of everything our team has achieved and inspired by the hard work put in by every single group across the company.”
— Harry O’Hanley, CEO at ABL Space Systems

ABL flexible system

ABL’s innovative launch system consists of two parts: the RS1 rocket and the GS0 ground system.

With RS1 the company aims to operate a low-cost, reliable, and flexible small satellite launch vehicle. The two-stage rocket is 27 m tall and can carry up to 1,350 kg of payload to LEO. The first stage is powered by nine LOX/RP-1, gas generator cycle, E2 engines. The second stage is powered by a single E2 Vacuum engine.

Block 2 Boost Engines, Radial (left), Center (right). Credits: Harry O'Hanley — *Block 2 Boost Engines, Radial (left), Center (right). Credits: Harry O’Hanley*

To be rapidly deployable, anywhere in the world, each RS1 stage is developed to fit in standard shipping containers. RS1 can be transported by sea, land, or air. Furthermore, the company developed GS0, a rapidly deployable ground system that only requires a 46 x 15 m flat concrete pad.

RS1 and GS0 flexibility allows customers to reach challenging orbits and is a key aspect for National Security missions. In September ABL was selected by the Space Systems Command (SSC) to demonstrate a Tactically Responsive Space (TacRS) launch.