Originally developed for NASA's Bantam System Technology program in 1997, the RS-88 burned ethanol fuel with liquid oxygen (LOX) as the oxidizer.

A hypergolic derivative of the RS-88, fueled by monomethylhydrazine and nitrogen tetroxide, was chosen as the launch escape motor for the Boeing Starliner capsule.

While the program envisioned a technology demonstration flight in late 1999, it ultimately focused on engine development.

A hypergolic derivative of the RS-88, fueled by monomethylhydrazine (MMH) and nitrogen tetroxide, was chosen as the launch escape motor for the Boeing Starliner capsule.

[4] Four LAE engines are used in Starliner's abort system to propel the capsule away from the launch vehicle in case of an emergency.