When in space you walk the torque

Please excuse the tacky pun in the title but this idea’s a ripper.

The current problem is how would you accelerate a spacecraft while it is in orbit. There are a number of standard ways to do this, most notably with the use of rocket engines. There may be another way that I have not seen before and that might work. It would be much easier than using rockets and the energy going directly into accelerating the spacecraft could be powered directly with electrical energy. It might only work for small corrections in orbit and it might make the crew of a spacecraft feel a little seasick or nauseous if it goes on for too long. But if it works for adjusting orbits it may save the need to place rocket engines on reusable earth-to-orbit spacecraft, which would be a huge advantage. It might also work as an electric powered propulsion system for satellites in space. At first blush the idea may look a bit silly to rocket science types, but if it does the job and it works, well…

The basic idea is to have two gyroscopic flywheels as far apart on a spacecraft as possible and then to coordinate them with each other by momentarily pushing against the rotational momentum alternatively in the two flywheels so that the spacecraft is accelerated sidewards in something like a repeated two-step walking fashion (biomechanics again). The space craft would be rotated like a rod with a fixed end whenever the rotational energy in the flywheels are pushed against. You would only allow the spacecraft to spin through a small arc before correcting with the opposing flywheel. It would work if the flywheels where housed in a gyroscopic kind of framework with three degrees of freedom and if the rotational momentum in the flywheels was not resisted within those frameworks, apart from those brief times that they are being pushed against to rotate the spacecraft sidewards. The angular momentum vector is best being as close to the direction of motion of the spacecraft as possible. Its difficult to explain with words.

It would be like using the rotational momentum of the flywheels like stepping stones when in space. You could use electrical energy to set the flywheels spinning and accelerate them, as well as when pushing against the flywheels, and when decelerating the flywheels you could do that by converting the energy back into electricity through the electric motor/generators running the flywheels. The energy that would accelerate the spacecraft would derive ultimately from the electricity feed into the flywheel and gyroscope systems. The flywheels could also serve to correct or change the pitch and roll of the spacecraft. They might have to be powered up and powered down in relatively short amounts of time and have this done in a coordinated manner with both of the flywheels working as a system. They would need to be computer controlled. I would imagine that they would be powered down during the launch of the spacecraft into orbit and then again when it is returning back into the atmosphere.

You could imagine large dumb-bell shaped satellites with a gyroscopic flywheel at each end, with a few solar collector surfaces, and that might be able to accelerate quite significantly in space. It would look strange to us at the moment given the kind of spacecraft we are familiar with. This idea needs to be tested of course. I haven’t seen any reference to such an idea for spacecraft propulsion before. I wonder whether you could build a system with a number of flywheels that you might be able to use to lift a light vehicle off a surface like the moon and with a slightly higher acceleration than gravity. It would look really funny, as if it were running to climb on all fours off the surface of the moon. Like I said, at first blush this idea may sound ridiculous but it might work. It’s not supposed to sound like a joke.

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14 Feb 2009

If the idea worked it could also work within the atmosphere.

Another question with regards to bush fires is whether you could build a fire fighting vehicle that could also handle the extreme temperatures of a wildfire, at least long enough to douse an area. You could imagine that instead of a smooth outer surface to such a vehicle, you could have something like heatsinks in reverse where water could be pumped to sit in metal trays kept a far distance (at least a few feet) from the body so that the heat from the fire could be evaporated away as steam before it heats up the vehicle’s body. The vehicle would have to be constantly moving to shed steam and there would have to be a very large surface area for the water heating surfaces. There could also be water poured constanly over the vehicle’s surface and windscreen and perhaps the surface could have micro terraces to hold water as it ripples down. The water tank would best extend over the whole undercarriage for such a vehicle and the water would also need to be pumped around the tank so that hot water could be replaced with cooler water that had some of its heat removed from it and extracted into the air above the vehicle.  There would also have to be some other ways to see where you are going, such as using some cameras with em frequencies that could see through the steam, smoke and heat – or you might even need something like a combination of radar, gps with a virtual dispaly of the terrain. Such a vehicle – if it was possible – could also be fitted with something like a bulldozer’s shovel towards the front so that it could flatten tall burning trees and build a firebreak as it is dousing an area. At this stage such a machine would be considered pure fantasy.