Interorbital Systems Corporation
HeadquartersMojave, California
Key people
Rod Milliron and Randa Milliron (founders)
Productsrocket engines, rocket launch
Number of employees
12 [1]

Interorbital Systems (IOS) is an American rocket and satellite manufacturer located in Mojave, California. The company was founded in 1996 by Roderick and Randa Milliron and is currently completing the development of the worlds lowest-cost orbital launch vehicles, the NEPTUNE, the TRITON, and the TRITON HEAVY.[1] Interorbital Systems was engaged in developing a launch vehicle for the Google Lunar X Prize Team Synergy Moon[2] and for commercial launches. The company was also a competitor in the Ansari X Prize[3] and America's Space Prize.[4]

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NEPTUNE Launch Vehicle: General

The two-stage NEPTUNE rocket uses high-performance liquid oxygen and densified propane propellants.[5][1] The first stage is powered by four stationary throttleable ablatively-cooled liquid rocket engines, each generating 10,000-lbf of thrust.[citation needed]Throttling of the engines generates the pitch, yaw, and roll control moments required for steering. By using throttleable stationary engines instead of gimballed engines, the heavy and complex gimbals, gimbal actuators, and the gimbal actuator drive hardware are eliminated, substantially reducing the weight and complexity of the propulsion system.[1] The second stage is powered by a single stationary ablatively-cooled liquid rocket engine generating 3,000-lbf of thrust. Cold-gas thrusters provide pitch, yaw, and roll control during the second-stage engine burn and on orbit. All of Interorbital's ablatively-cooled rocket engines are rapidly manufactured using a filament-winding process. These state-of-the-art composite engines are manufactured with the most advanced high-temperature resistant composite materials allowing the engines to be safely operated for up to forty minutes. They are more reliable and much lighter than the typical regenerative-cooled engines that use primitive nineteenth-century steam-engine technology for cooling and they simplify the engine plumbing and the multiple engine start process while on orbit.[6]

NEPTUNE Launch Vehicle: Pressure-fed Propulsion System

The propellants are fed into the NEPTUNE liquid rocket engines by a proprietary pressurant system that does not require dangerous and heavy high-pressure pressurant tanks. This system design results in a propellant tank/pressurant system that weighs the same as an equivalent propellant tank/pressurant system/pump-fed system. By eliminating the propellant pump and its heavy electric or gas-generator pump-drive system, we have substantially reduced both the overall rocket development cost and the manufacturing cost and manufacturing time.[7]

NEPTUNE Launch Vehicle: Exclusive Ocean-based Launch

All IOS rockets are launched from an ocean-going barge with motion compensation. Equivalent to a private spaceport, barge-launch eliminates the enormous cost of liability insurance when launching from the existing land-based spaceports and allows IOS to schedule launches based only on the weather and sea conditions. Initially our orbital flights will take place from the Pacific Ocean southwest of Los Angeles.

In 2006, IOS had an active Office of Commercial Space Transportation launch license for Tachyon,[8] a sounding rocket designed for a 120-mile apogee suborbital flight.

Preliminary design concepts


Test flight of the single CPM on March 29th, 2014 with four payloads on board.
Test flight of the single CPM on March 29th, 2014 with four payloads on board.

Satellite kits

They claim that kits will be launched into 310 km (192 mi) self-decaying orbits where they will eventually burn up in the Earth's atmosphere.[citation needed] They have a large launch manifest for both kinds of launches.[11][non-primary source needed]

Google Lunar XPrize

Interorbital Systems was engaged in June 2016 as a member of and launch provider for Team Synergy Moon in the Google Lunar X Prize competition.[12][2] The team's lunar rover was to have been lifted to the Moon's surface by a modified, 36-module version of the NEPTUNE rocket.[13]

See also


  1. ^ a b c d "Western Pa. couple shoot to win Google Lunar XPRIZE on humble budget". 15 February 2017.
  2. ^ a b "TEAMS Google Lunar XPRIZE". Archived from the original on 2018-01-24. Retrieved 2018-01-23.
  3. ^ "X PRIZE Team Summary Sheet: Interorbital Systems" (PDF). X PRIZE Foundation.[dead link]
  4. ^ a b Boyle, Alan (October 8, 2004). "Space racers set sights on orbital frontier: After X Prize, some rivals seek more lucrative payoff". NBC News. Archived from the original on December 3, 2015. Retrieved 2013-08-11.
  5. ^ Milliron, Randa (October 2017). "Interorbital Preps for NEPTUNE Test Launch—and eleven smallsats will go along for the ride". SatMagazine. Archived from the original on 2018-01-24.
  6. ^ Missing or empty |title= (help)
  7. ^ "Synergy Moon Presentation at 2011 GLXP Summit". YouTube. 2011-07-16. Archived from the original on 2015-12-03. Retrieved 2013-08-11.
  8. ^ Milliron, Randa (2006-05-28). "Advantages of Using White Fuming Nitric Acid (WFNA) as an oXidizer in Rockets". Lunar Lander Challenged. Archived from the original on 2015-12-03. Retrieved 2013-08-11.
  9. ^ a b "CPM TV Rocket Launch 03.29.14". Archived from the original on April 7, 2014. Retrieved May 6, 2014.
  10. ^ "Album Launch: John Frusciante Sends New LP Into Space on Rocket". 2014-03-31. Archived from the original on 2016-07-30. Retrieved 2016-06-27.
  11. ^ "Launch Manifest". Interorbital Systems. Archived from the original on 2018-01-12.
  12. ^ "Lunar Missions_1". Archived from the original on 2016-07-06. Retrieved 2016-06-05.
  13. ^ "XPRIZE Verifies Launch Agreement for Team SYNERGY MOON as Third Google Lunar XPRIZE Team Pursuing a 2017 Lunar Mission". Business Wire. 30 Aug 2016. Retrieved 4 Feb 2021.