ABL preparing for second launch attempt of its RS1 rocket

ABL’s redesigned rocket launch mount
Since its first test launch of its RS1 rocket failed in January 2023, ABL has spent the last ten months doing major revisions of the rocket’s launch mount as well as preparing an upgraded new rocket for a second test launch attempt, expected in the coming months.
This information comes from a long update posted by the company’s CEO, Harry O’Hanley on October 25, 2023.
It appears failure occurred because of a fire at the base of the rocket after liftoff, which in turn was caused by the small size of the rocket’s launch mount.
By analyzing video and data, we formulated a leading theory behind the source of the fire. Our hypothesis centered around the Launch Mount, which is the GS0 assembly that raises and lowers the vehicle. It was designed to fit fully assembled inside a shipping container. While this made transport simple, it resulted in the rocket being held close to the ground.
We believe the compact Launch Mount and proximity of RS1 to the ground restricted the flow of engine exhaust gas. This caused plume recirculation and drove pressures and temperatures beneath the rocket to exceed the RS1 base heat shield design capability. The hot combustion gases breached the aft heat shield and initiated the engine compartment fire. We corroborated this theory with a variety of tests and analyses, including multi-species CFD performed both in-house and by an independent partner.
The graphic to the right, rearranged and annotated to post here, shows the new larger mount. Because of the time it has taken to make that launch mount upgrade, the company also decided to fly its next version of RS1 on this second test launch, rather than the backup rocket from the first launch. This upgraded RS1 has 20% more thrust with a detachable engine section that makes access to it much easier.
O’Hanley made no mention of a specific target launch date from the Kodiak spaceport in Alaska, but his post implies the launch is coming very soon.
ABL’s redesigned rocket launch mount
Since its first test launch of its RS1 rocket failed in January 2023, ABL has spent the last ten months doing major revisions of the rocket’s launch mount as well as preparing an upgraded new rocket for a second test launch attempt, expected in the coming months.
This information comes from a long update posted by the company’s CEO, Harry O’Hanley on October 25, 2023.
It appears failure occurred because of a fire at the base of the rocket after liftoff, which in turn was caused by the small size of the rocket’s launch mount.
By analyzing video and data, we formulated a leading theory behind the source of the fire. Our hypothesis centered around the Launch Mount, which is the GS0 assembly that raises and lowers the vehicle. It was designed to fit fully assembled inside a shipping container. While this made transport simple, it resulted in the rocket being held close to the ground.
We believe the compact Launch Mount and proximity of RS1 to the ground restricted the flow of engine exhaust gas. This caused plume recirculation and drove pressures and temperatures beneath the rocket to exceed the RS1 base heat shield design capability. The hot combustion gases breached the aft heat shield and initiated the engine compartment fire. We corroborated this theory with a variety of tests and analyses, including multi-species CFD performed both in-house and by an independent partner.
The graphic to the right, rearranged and annotated to post here, shows the new larger mount. Because of the time it has taken to make that launch mount upgrade, the company also decided to fly its next version of RS1 on this second test launch, rather than the backup rocket from the first launch. This upgraded RS1 has 20% more thrust with a detachable engine section that makes access to it much easier.
O’Hanley made no mention of a specific target launch date from the Kodiak spaceport in Alaska, but his post implies the launch is coming very soon.