A Non-Toxic Fuel From the Mojave Desert

Late next year, a cargo freighter will deliver a potentially revolutionary new propulsion system to the International Space Station.

Franklin Chang-Diaz’s VASIMR engine? No, that test is still a couple of years off.

The propulsion system is called NOFBX. It’s a green fuel system developed by a little-known Mojave-based R&D company called Firestar Technologies. And it could well be one of those “game changing” technologies that NASA officials believe will make space travel a lot more affordable.

So what is NOFBX? It is a high-performance nitrous oxide/fuel/emulsifer blended mono-propellant that is non-toxic, low cost and easy to produce, says Greg Mungas, its developer and CEO of Firestar Technologies. The fuel has a number of key applications, including on space stations, commercial crew vehicles, sample return missions, and human expeditions to the moon and Mars.

The goal is to replace toxic hypergolic propellants that are now used on spacecraft. NOFBX can be made from chemicals that are widely available, and it can be transported and handled without excessive precautions. And that makes everything easier, safer and cheaper. For example, when the Air Force’s X-37 reusable space plane landed in California last year, it was surrounded by a group of technicians dressed in safety suits because of toxic fumes. NOFBX also reduces liability. It takes almost a metric ton of fuel to get a spacecraft back on the ground. Carrying that much fuel, which resembles Agent Orange, over a populated area is a large liability for companies.

“It’s a technology that helps reduce cost. Companies that have big cost models and understand what that impact is, they come in and they appreciate it immediately,” Mungas said.

Developers of reusuable spacecraft are eyeing clean fuels for their vehicles. Mungas said that it is possible that Firestar will supply NOFBX for future Dragon flights to the International Space Station.

“We have an ongoing discussion, and we are folding in requirements and needs from SpaceX to make sure that we can support upgrading their systems to a non-toxic system in the future,” Mungas said.

The toxicity of current fuels causes problems for space station astronauts. Every time a thruster is fired on the station, there is not enough pressure in the chamber to cause combustion. As a result, a cloud of thin film gets emitted that floats around the station and eventually sticks to it, Mungas explained. ISS has now accumulation of thin gel of hydrazine based sulfur that spacewalking astronauts are beginning to bring it back in. That problem will only become larger as the space station grows older, he added.

In the ISS test, a NOFBX engine will fly on a pallet aboard a SpaceX Dragon spacecraft or Japanese HTV freighter. After the Canadian arm will attach it to the truss of the space station, engineers will put the engine through a series of critical thrust modes, including station reboost, rendezvous and docking, and deorbit burns.

There is an 18-month window between contract signing and the flight, which is a fairly turnaround time. Before anything goes to ISS, it must be approved by the Safety Review Panel, a rigorous process that Mungas calls the “gold standard certification for flight.” Once the panel approves the technology, getting it on unmanned ships will be easy, he added.

In addition to the space station, another really useful application is in planetary exploration. Non-toxic fuels will not contaminate a landing site on Mars where a robot will collect samples for return to Earth. Astronauts at a lunar base will not have to worry about contaminating their habitats with toxins that have been deposited by repeated landings at the same site.

Planetary exploration is really where Firestar got its start in non-toxic propellants. The company was founded in 2002, and it got involved in some initial Mars sample return studies. Two years later, Firestar got a big contract from NASA’s Jet Propulsion Laboratory develop a non-toxic fuel. That project lasted until 2007.

Firestar soon got pulled into exploring the use of NOFBX in supporting NASA’s Constellation program, which aimed at sending humans back to the moon. The company received a 2008 subcontract to support work on the Altair lunar lander. At the time, NASA was looking at sending astronauts down on the moon at the same location on a repeated basis, requiring clean propellants.

Firestar is now working on a NASA contract to research, develop, and test a compact, restartable Single-Stage-to-Orbit (SSTO) ascent engine for NASA’s Mars Sample Return (MSR) vehicle. The SSTO would take off from the surface and rendezvous with an orbital spacecraft that would return samples to Earth.

A Mars single-stage-to-orbit sample return vehicle.

Overall, it is a very busy time for Firestar, an R&D company that does about 80 percent of its work in the propulsion field.  The main goal is to generate intellectual property, and it has spun off several companies to work in specific areas.  The 2012 ISS test, for example, is actually being done by a team led by one of Firestar’s spinoffs, Innovative Space Propulsion Systems (ISPS). The Houston-based manufacturing company is a partnership of: Odyssey Space Research; Firestar Technologies, LLC; Ventions, LLC; Micro Cooling Concepts (MC2); mv2Space; and Lightning Aircraft Corporation.

Firestar also has been hard at work on another project: a spinoff from a military project that has applications much closer to home. But, that’s another story that I will write about tomorrow.

  • The article lacks details on the nature of the propellant. We are told that it is mono propellant – that it is a sort of emulsion of fuel particles in N20. That sounds plausible – but quite explosive.

    Most liquid mono propellents has stability problems – and the truly interesting thing about this is how Greg Mungas solves this challenge.

    Astronauts on the ISS may be hydrazine intoxicated as it is, but it would hardly be better if they are detonated instead.

    Even pure nitrous oxide have been known to explode under certain conditions of temperature and pressure – so adding a fuel to the oxidizer must add to the likelihood of unwanted combustion.

    Intellectual property ? Ha – well – tell us how it works Sir, or keep it. The simple way learning inventors the meaning of the term “open source” is not to buy their products until they let their costumers know how it works.

    On the technical level – getting rid of hydrazine and replacing it it nitrous oxide / hybrid or bi fuel systems is a good idea. If it really needs to be
    mono propellant and non toxic, hydrogen peroxide is likely the only option. However at nitrous oxide hybrid is not more complex with regards to valves
    ( one valve only ) than a mono propellant system.

    I hope Greg Mungas has come up with something new and wish Firestar the best of luck. But do tell us more, its sounds exiting !

    Peter Madsen, Copenhagen Suborbitals.

  • Ray Alderman

    I never understood why XCOR spent the time and money over the last year or so to develop internally basically the same thing – a non-toxic fuel for the thrusters on the Lynx.

    XCOR has stated a few times that this was a hard thing to do and much trickier than they thought initially. And yet, a few doors down, there was the Firestar guys selling exactly that, already developed.

    So there has to be a story/reason there why XCOR just didn’t buy it off the shelf from these guys. Wonder if that will ever be made public.

  • Tom Billings

    For those who want a bit more detail on the fuels in in the NOFBX series:


    These are, essentially, Ethane, Ethylene, and Acetylene, along with unspecified emulsifiers. I would assume that the emulsifier both improves miscibility, and stabilizes the mixture. Given the acetylene option especially, stabilization would be good. This is especially hopeful in that Firestar claims their propellant series withstands a drop test between steel plates of 30 feet, without detonating.

    If that, and the claimed ISP of 266 (sea level) and 320 (vacuum) are sustained in practical use, then we have an extremely useful propellant here. Perhaps it will be useful for main propulsion duties for launchers. The operational advantages of NOFBX, combined with the claimed performance, would help lots in making the next launcher company to show up on the scene competitive with SpaceX.

    Industrial production of N2O is already substantial, as is that of the fuels. As long as the emulsifiers used are not super-costly, then this propellant may have a price at the pad quite competitive with LOX. If, in addition, the flashback prevention plumbing on the motors using NOFBX is easily manufactured, and the motors reusable, then this may well be as “revolutionary” as this article claims. Time will tell.

  • Thanks, Tom.

    There’s more information about the technology at http://www.firestar-engineering.com/NOFBX-MP.html