Patent ID: 7484692

Claim:
An orbital stage comprising: wherein the orbital stage has an initial mass; a first propellent tank containing propellent mounted to and forming part of the orbital stage; a plurality of orbital maneuvering system (OMS) engines, each engine having a selected design thrust and being mounted to and forming part of the orbital stage, and connected to receive a flow of propellent from the first propellent tank; a valve for each OMS engine arranged to control the flow of propellent from the first propellent tank to the OMS engine; wherein the combined design thrust of all the OMS engines along a single vector is less than that sufficient to accelerate the orbital stage initial mass at an acceleration of 32.17 ft per second squared; at least one abort engine having a selected design thrust, the at least one abort engine mounted to and forming part of the orbital stage the orbital stage, and connected to receive a flow of propellent from the first propellent tank, wherein the combined design thrust of the at least one abort engine along a single vector is sufficient to accelerate the orbital stage initial mass at an acceleration greater than about 3 times 32.17 ft per second squared, wherein each of the plurality of OMS engines has an area ratio of at least 25 times an area ratio defined by the at least one abort engine.