SpaceShipTwo to be fueled by thermoset plastic similar to nylon


May 27, 2014

Virgin Galactic's SpaceShipTwo, shown here on a test flight, will be fueled by a thermoset plastic similar to nylon

Virgin Galactic's SpaceShipTwo, shown here on a test flight, will be fueled by a thermoset plastic similar to nylon

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As the still-to-be-announced date of the first commercial flight of Virgin Galactic’s SpaceShipTwo approaches, more and more of the technology involved is getting nailed down. A case in point is the company's announcement that it has decided which fuel will be used in the first passenger-carrying flights of the suborbital spacecraft. The solid fuel grains that will fuel the world’s largest operational hybrid rocket will be a thermoset plastic similar to nylon.

When SpaceShipTwo launches after being dropped by the WhiteKnightTwo carrier aircraft, it will be powered into orbit by a hybrid rocket motor developed by Sierra Nevada Corporation that uses solid rocket fuel and nitrous oxide as an oxidizer. The gas oxidizer means that, unlike conventional solid rocket motors, it can be shut down at will.

Its predecessor, SpaceShipOne, used hydroxyl-terminated polybutadiene (HTPB), which is a classic fuel for solid rocket motors. But after reviewing data collected from static test firings, Virgin Galactic has decided on an alternative fuel for the remainder of the test flights of SpaceShipTwo and for the first commercial flights.

Instead of HTPB, the rocket motor will now use a fuel based on polyamide, a class of thermoset plastics of which the most well known is nylon. It is used in everything from clothing to airbags and industrial plastics, and has the added advantage of not requiring any redesign of the motor, which was built to regard the two fuel grains as interchangeable.

SpaceShipTwo is designed to take six paying passengers on a suborbital flight from the Virgin Galactic Spaceport America in the Mojave desert into space. Once there, the passengers can look back at Earth and enjoy several minutes of zero gravity. According to Virgin Galactic, the spacecraft can also be fitted with equipment racks to carry experiments and the technology used can also be adapted to launch micro-satellites into low Earth orbit (LEO).

The video below shows a static test firing of the rocket motor.

Source; Virgin Galactic

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

Really, you should know better than that.

To say a hybrid rocket runs on plastic fuel is almost like saying a car is electric because it runs on spark plugs.... Compare the ratio of nitrous to plastic. The plastic is MINISCULE.

A hybrid rocket cannot even really be compared with a solid rocket-it is gas dependent.

The plastic can be removed and another gas can be added to the nitrous so it could burn without the plastic (upon ignition) and then it would be a standard "liquid" rocket.

Nitrous oxide enhances combustion but it does not burn... alone.

Anyway, solid rockets are like bottle rockets- light 'em and they are gone... 'til they burn out. Disposable(usually).

There is so much confusion about jets, turbines, rockets, ram jets, scram jets, JATO, RATO, etc.

Articles like this foster that ignorant confusion instead of dispelling it.

Nothing personal, but I have heard that you have an aerospace orientation and I would sure would like to see better from you.

This is just sensationalism- "Wow! Flying to space with PLASTIC as fuel!"

Plastic is just one more product/byproduct of the petrochemical industry. If you could use plastic as fuel alone, the toxicity would be horrible.

Where are the rail guns?

That's what will put material payloads into space cost-effectively and be clean. (depending on the power source,of course!)

BTW, since Tesla is all about converting the world to electric, why does Musk still use the biggest combustion engines on the planet?

As for this, you can always expect Branson to play P.T.Barnum. Please don't play into his ignorant sensationalism.


Nylon is not a thermoset plastic. It is a thermoplastic. Thermoplastics can be melted and solidified over and over, with no appreciable chemical change. Thermoset plastics are usually two components mixed together that react and cross-link with each other to form a larger polymer, either by means of heat or at room temperature. Once cross-linked and "cured," they cannot be remelted to be used again. Trying to melt them causes them to decompose. A common example of a thermoset plastic is cured epoxy resin, used as an adhesive or in fiber-reinforced plastic. Thermoplastics are polymer chains that are tangled rather than cross-linked. This enables them to untangle when they are melted and re-tangle when they are cooled. More than you may have wanted to know....


I think we should build something to let rich people spew gargantuan quantities of toxic pollution high into our atmosphere, just so they can boast about spending a couple of minutes being almost up in space.


So - Not exactly ecofriendly power then? I would say that the stuff sent out the rear of this engine is just as polluting as most of the alternatives. Looks to me that the only advantage is that, like liquid fuel engines, these are controllable and can be turned on and off for final use later in the flight.

The Skud

@ Griffin The nitrous oxide is the oxidizer the plastic is the fuel making it hybrid rocket because its propellent uses both a liquid component and a solid component. Learn a little before you rant you will look less stupid.


I would prefer two compressed to liquid binary propellent like Nitrous oxide and propane/butane. Being able to dump the fuel as well as the oxidizer sounds like a good idea to me.


griffin, in light of your most recent comments, it appears that you've lost perspective. The treatment is simple, safe, and effective.

Breathe in. Breathe out. Breathe in. Breathe out..

Repeat as often as needed.

Noel K Frothingham

Well in layman's terms... It exploded.

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