December 06, 2007

Enhancing magnetic sail launches using Light weight high volume magnet production

In theory, it is possible for a magnetic sail to launch directly from the surface of a planet near one of its magnetic poles, repelling itself from the planet's magnetic field. However, this requires the magnetic sail to be maintained in its "unstable" orientation. A launch from Earth requires superconductors with 80 times the current density of the best known high-temperature superconductors.

Other magnetic launching systems tend to use stronger magnets and shorter launch systems.

The earth's magnetic field is about 60 microtesla at the poles.


The above image is the traditional space pier invented by J Storrs Hall


The 3 columns (2 supporting columns and one main set of columns) with magnetized coating of magnetic material that could generate 4800 or more microtesla then existing superconducting wire would be sufficient to ground launch a magnetic sail.

Note: the main ramp could also be a cylinder that would guide and assist a laser array launch vehicle. The cylinder might pump out the air to assist the mirrored laser array luanched vehicle.

Compared to the skyhook, which is just barely possible with even the theoretical best material properties, a tower 100 km high is easy. Flawless diamond, with a compressive strength of 50 GPa, does not even need a taper at all for a 100 km tower; a 100-km column of diamond weighs 3.5 billion newtons per square meter, but can support 50 billion. Even commercially available polycrystalline synthetic diamond with advertised strengths of 5 GPa would work. Of course in practice columns would be tapered so as not to waste material; and the base of the tower would be broadened to account for transverse forces, such as the jet stream. Only the bottom 15 km (i.e. 15%) of the tower lies in the troposphere and would have to be built taking weather into account.

One of the interesting challenges in designing the structure is that simple diamond columns only thick enough to support its weight would be too thin to be rigid. Two strategies which can be brought to bear are truss structures and thin shells inflated for stiffness. At higher altitudes hydrogen could be used for inflation, since there is insufficient oxygen for combustion. At altitudes below the tropopause, some attention should be paid to reducing the structure's wind cross section to minimize the effects of hurricanes and the jet stream. It is not inconceivable that the jet stream, or cloud-to-ground voltages, could be used as energy sources


There has been discussion about augmenting the earth's magnetic field to enable ground launches of superconducting magnetic sails.

Magnetic sails have been considered for many space missions.

The magnetic sail was a target of speculation for science fiction games.


The team, led by UVic chemist Dr. Robin Hicks, discovered a simple method for making a new family of organic-based magnets by combining nickel and one of three different organic compounds. The discovery is the first step in designing the next generation of magnets which could, in theory, be easily manipulated at room temperature.

FURTHER READING
Rand Simberg makes the case for the primary space launch cost problem being the lack of economies of scale.

It should be clear that space launches are so expensive not because of the amount of energy required or the laws of physics in general, but because of the way we’ve chosen to undertake them, and the fact that we do so few of them. In the case of the expendables, it’s because we throw away expensive hardware with every flight; in the case of reusables, it’s because we don’t reuse them very much. This suggests that the key to low-cost and reliable launch is the following: (a) to stop throwing the launch vehicles away, in whole or in part, and (b) to fly them a lot.

The emphasis is on low cost from the outset. As Jeff Greason, president and co-founder of the private company XCOR Aerospace, has explained, it’s easier to figure out how to do something reliably and affordably and then get more performance out of it, than to focus on the ultimate performance first and try to reduce its costs and increase its reliability later.

Thus the suborbital spacecraft in private development today can be scaled up to reach greater altitudes, extending the performance envelope further with new vehicle designs, while still maintaining low costs per flight. And if there are multiple companies building such vehicles, they’ll be able to learn from each other’s mistakes and innovations as well. Mach 5 can become Mach 7, Mach 7 can become Mach 12, Mach 12 can eventually become Mach 25 and orbit, as experience is gained and designs evolve.


Spaceship two is to be revealed next month, January 2008, just before flight testing starts.

Following a series of 50–100 test flights, the first paying customers are expected to fly aboard the craft in late 2009. SpaceShipTwo will carry 6 passengers and 2 pilots and launch in midair at 15 km from its mother ship, WhiteKnightTwo. More than 65,000 would-be space tourists have applied for the first batch of 100 tickets to be available. The price will initially be US$200,000. The deposit for the passengers going in the first year, but after the first 100 is around $100,000. The deposit after the first year will drop to around $20,000.The duration of the flight will be approximately 2.5 hours, and weekly launches are planned.

Spaceshipthree and spaceshipfour are to be orbital spaceplanes.

Burt Rutan thinks the key is increasing safety.

A minimum is 1-in-30,000 chance of an accident, a level similar to that of modern fighters. However, that is more than two orders of magnitude better than current space systems, which have a 1-in-66 chance of a fatal accident. (almost 500 times safer).

Each SpaceShipTwo vehicle will be capable of two flights a day. Rutan did state at one point that SS2 will look “a lot different” from SS1, with a low wing instead of a high wing “because we had way too much dihedral effect, which gave us stability control problems on boost.”

“We hope to build at least 50 spaceships,” he said, “and we believe that at the direct operating costs that they will be operating under, ticket prices will come down to the level where millions of people can afford to do this.”


A high volume capacity for flights and a high volume market if not too many customers get killed. First sub-orbital and then orbital.

Beyond a high volume tourist and entertainment market is space mining, accessing space energy and space colonization.

5 tesla room temperature permanent magnet.

5.5 tesla permanent magnet.

Magnetic leviation

Island one survey of earth to orbit launch systems

Space fountain at wikipedia

Launch loop at wikipedia

Orbital rings at wikipedia

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