Active Magnetic Bearings

Commercialising the Moon: the Lunar X Prize and beyond

Next year marks the 40th anniversary of the last manned voyage to the Moon. The Apollo 17 astronauts, Eugene Cernan and Harrison Schmitt (the latter, a geologist, the only scientist-astronaut of the Apollo programme) left the Moon on 17 December 1972, leaving behind them a plaque bearing the words: ’Here man completed his first explorations of the Moon.’

With the last mission of the space shuttle underway and NASA’s plans for future manned missions to space seemingly on hold, it might seem odd to talk about the Moon as a target for exploration. But for a number of organisations, the race to the moon is back on, with the prize of increased scientific knowledge and, some are convinced, of enormous financial gains.

The US, Russia, Japan, China and India all have active manned Moon-landing programmes with somewhat elastic timetables. Moreover, 29 teams are competing for a $30m (£19m) prize, funded by Google, to be the first privately funded organisation to land a robotic probe on the Moon.

Google is funding a Lunar X Prize, one of the competitions organised by the US-based X Prize Foundation, aimed at solving technology-based problems without public funding. The best known of these, the Space X Prize, was won in 2004, with Scaled Composites’ SpaceShipOne taking the $10m prize for the first suborbital flight of a non-government-funded craft.

The Space X Prize was the springboard for Virgin Galactic and SpaceShipOne’s successor, SpaceShipTwo, is currently undergoing flight trials ahead of a planned first commercial flight later this year. With Virgin Galactic claiming to have secured some 500 customers, each paying $200,000 for their flight, commercial space flight certainly seems to be a sound and potentially lucrative venture. The Lunar X Prize entrants have similar hopes.

’Some people argue that the first group of trillionaire entrepreneurs will be involved in the commercialisation of space,’ said Michael Potter, leader of the first team to register for the Lunar X Prize, Odyssey Moon. Based on the Isle of Man, although working mainly from San Francisco, the organisation has already secured a number of customers for lunar landing services from a surprising range of sectors, from hard science to performance art. With Potter quoting costs of up to $5m per pound of payload, it certainly seems like the Moon is a viable business proposition.

’Even now, people say that we shouldn’t commercialise space because of all the problems we have on Earth, but the reality is that in the last 20 to 30 years there’s been a tremendous growth in the commercial business of space; global positioning is a multibillion-dollar business and so are commercial communications satellites,’ he said. ’We’re trying to take it to the next level. We want to bring many of the same business models and disciplines that are used for commercial satellites the launch business, the insurance business, even the maintenance business to use the Moon as an extension of the geostationary orbit. All of these things can go to that next frontier, which is the commercialisation of the Earth-Moon system.

Realization of the magnetic bearing pump

The paper presents analytic design of active magnetic bearing PM synchronous motor for

TAH (Total Artificial Heart) application and description of the drive and levitation

electromagnet control. Pump system is double ventricle blood pump consisting of slotless

PM axial flux synchronous machine and magnetic active bearings. The general electric

machine theory is applied to the motor design. Power quality is ensured by the help of the

rare earth PM and for good torque quality is used slotless, three phase winding and surface

mounting PM. Control part deals with the synchronous In our solution Fig. 1 the drive system

consisted of the permanent magnet synchronous slot-less motor and magnetic active radial

bearings. These systems were tested both on the air and water environments. Problem of

the magnetic bearings and electrical drive is very the same also for other type of the

rotating pumps.

At the first pump design, the base requirement was hydraulic output

power. Rare earth magnets, which were developed in the last half of the 20th century, are considered permanent in nature and extremely strong. These magnets are used for industrial needs such as electro dynamic bearings and in the motors of many cordless drills as a component of the motor, commercially in audio video equipment and even in the making of modern science type toys and puzzles. At this stage of design, properties and possible damage of blood elements were not

be reflected. The pump contains 3-phase synchronous disk-type machine with slot-less

winding (magnetic circuit doesn't contain any ferromagnetic materials), double sided rotor

with permanent magnets and integrated turbine blades and two active axial magnetic

bearings.

Miniature controller "Easy 25" for brushless motors, mostly used for  model motors, was

found to be very useful for artificial heart motor supply. is done automatically. The controller

is designed for the brushless sensor-less motors. Magnetic bearing has generally five

control channels, four radial and one axial. For mostly used control systems each control

channel has autonomous control and input signal is coming from the position sensors and

systems have one degree of freedom. In the next text we will deal with one degree bearing.

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