Here are some questions we’ve been asked so far. If you have any others, feel free to comment, or contact us.
So, how does it work?
That’s a long explanation. We have a great Science page that explains how the drive works.
What does it burn for fuel?
In short, anything that conducts electricity, though some things work better than others. We’ve tried various kinds of metals and even carbon rods. Some of which give us more fuel efficiency, some more power, and some are just more ubiquitous in outer space. Our Science page has more detail.
Do you have a real one working or is it still just theory?
We have a real one working in the lab right now. We haven’t yet tested it in space-equivalent conditions (but we’re working on that). According to NASA’s Technology Readiness Level scale, we are at TRL4
Can you launch a spacecraft with it?
No, the Neumann Drive is not designed to launch spacecraft – it doesn’t have enough thrust for that. It’s better at being very fuel efficient, rather than at throwing a lot of power out the back over a short time.
So what is it good for then?
It’s good for keeping satellites in their proper orbit for many, many years. Also for slowly-but-efficiently sending probes out to far-reaching places like asteroids. Also for sending equipment and supplies ahead of a manned mission.
Being fuel efficient is really important in space because after a while you start to need to carry fuel in order to push the mass of existing fuel, which also needs more fuel to push it… which leads to an exponential explosion in the amount of fuel needed for a mission. This XKCD comic on fetching back Voyager will give you a good idea at how quickly it can escalate. Being more fuel efficient is perfect for missions where time-to-arrive is less important than requiring so much fuel as to be too expensive to go at all.
As another example: the ISS alone requires seven tonnes of liquid fuel brought up to it each year to keep it on course. It costs a lot of money to bring up a kilo of anything into space, and estimates range from UD$10,000 to US$50,000 per kilo… which multiplied by 7,000 leads to a minimum of $70 million at the cheapest rates. A more efficient engine would require less fuel needing to be brought up – which would result in a dramatic reduction in costs.
A more efficient fuel for station-keeping on the ISS could involve the same money being paid for the launch, but free up most of that seven tons for equipment to do more science on the ISS, or work on delayed projects such as an industrial module to allow space manufacturing, or spare parts to improve its operating life.