The quad vehicle design is a pressure fed in blow-down[clarification needed] mode from an initial pressure of 320 psi for level 1 (400 psi level 2).[citation needed] The cold gasvernier engines are cross-fed by gas drawn from ullage space of the opposite tank. The vehicle was able to transfer propellant through connecting pipes between opposite tanks by controlling ullage pressures with the thrusters; this helps it balance, minimizing gas use. The main engine had two-axis thrust vectoring.[citation needed] The vehicle was fully computer controlled; with guidance from GPS and fiber optic gyros.
Specification
The specification for Pixel/Texel for level 1:[citation needed]