Interorbital Systems

Interorbital Systems is a privately held American rocket company founded in 1996 by Roderick (Rod) and Randa Milliron and based at the Mojave Air and Space Port in Mojave, California. The company has spent almost three decades developing the modular NEPTUNE family of orbital launch vehicles, built around a Common Propulsion Module (CPM) — a cluster of small liquid-oxygen/densified-propane rocket engines, each producing roughly 4,500 lbf of thrust — that can be grouped in different quantities to scale the rocket's payload capacity; related TRITON and TRITON HEAVY variants have also been proposed.

Alongside the launch vehicle work, Interorbital sells low-cost 'TubeSat' and 'CubeSat' personal satellite kits to schools, hobbyists and research groups, intended to be flown as rideshare payloads once NEPTUNE or a partner vehicle is available; the company has used ISRO and JAXA rideshare opportunities to fly some customer payloads, and also developed the suborbital NEUTRINO and TACHYON sounding rockets. Interorbital served as the launch-vehicle partner for Team Synergy Moon in the Google Lunar X Prize, and earlier competed for the Ansari X Prize and America's Space Prize.

Despite multiple announced static-fire and suborbital test campaigns dating back to the 2000s, Interorbital Systems has not yet completed an orbital launch; as of October 2023 NEPTUNE, TRITON and TRITON HEAVY remained in development, with the company reporting around a dozen employees as of 2017. The company continues to operate from Mojave.