Helicon Double Layer Thruster

The Helicon Double Layer Thruster is being developed in the Space Plasma and Plasma Processing Group (led by Professor Rod Boswell) of the Plasma Research Laboratory (Research School of Physical Sciences and Engineering) at the Australian National University in Canberra (Australia). Dr Christine Charles has invented the world's first Helicon Double Layer Thruster or HDLT. This new propulsion concept has the potential to propel humans to Mars and beyond and greatly decrease the costs of maintaining satellites and spacecraft in their desired orbits.

The website of the Space Plasma and Plasma Processing Group can be found here.

Researchers from the Cooperative Research Centre for Satellite Systems and Australian National University have teamed up to develop and test the satellite motors of the future, based on a revolutionary plasma thruster.

"If we can develop a cost-effective thruster that will keep working for decades, it will provide a dramatic boost to satellite life," explains CRCSS chief executive officer Dr Andrew Parfitt.

"Today one of the biggest problems is that geostationary satellites run out of fuel and can't be kept in position. We believe the ANU's plasma thruster may be the solution."

The answer is already working on the ANU's test-bench - the Helicon Double Layer Thruster (HDLT) invented by Dr Christine Charles using the helicon technology patented by Professor Rod Boswell.

The thruster uses radio energy to create a plasma - a cloud of ions (atoms with an electron missing), atoms and electrons - out of a gas such as argon. These ions then pass through a sharp drop in electrical potential that, in the space of a few millimetres, kicks them to speeds of around 10 kilometres/second. This provides the thrust.

Dr Charles made this remarkable Australian scientific discovery on April 8, 1999, while testing various combinations of magnetic field and pressure levels on an experimental thruster, in an experiment run in her spare time. She observed the dramatic increase in speed of the particles as they passed through the drop in electrical potential.

"Often in science you think you've found something, then you come back the next day and you can't recreate the same effect. This time it was there every time - it's a really important Australian discovery," she says.

For the next four years Dr Charles continued to work on the device without funding until 2004 when the CRC/ANU partnership received a grant from the Innovation Access Programme- International Science and Technology (IAP-IST) established under the Australian Government's innovation statement, Backing Australia's Ability, to design and test a plasma motor for steering satellites to keep them in orbit.

Prof Boswell explains that plasma thrusters have advantages over rocket engines in that they use an electrical power source (such as a fuel cell, solar or thermal-nuclear) which gives them a long life, and do not have to carry the rocket's heavy chemical fuel load.

"An ion rocket is always accelerating, which gives the added advantage that it has a 'down' - a kind of gravity, compared with other craft where you just float around."

Prof. Boswell's colleague, NASA space engineer Dr Franklin Chang-Diaz, has calculated the trip to Mars can be reduced by two thirds to around three months if plasma thrusters were used instead of conventional rocket motors.

The CRCSS/ANU team's brief is to prove up the technology for an immediate practical outcome - keeping costly communication, navigation and earth observation satellites in service much longer, by steering them gently back into orbit.

Two recent US and European spacecraft have been powered by experimental plasma thrusters, but the Australian team is confident their technology is superior in several ways - including emitting a plasma beam that does not need to be artificially neutralised, as is the case in other thrusters.

To find out exactly how much thrust the HDTL is actually capable of developing, it has to be run in a vacuum chamber which mimics conditions in outer space.

Dr Charles and Prof. Boswell leave for Europe this week to inspect the European Space Agency's facilities in the Netherlands and establish the requirements for the design of the prototype satellite thruster and its trials, which are planned for February 2005.

"The Satellite CRC, with the backing of IAP-IST, has grasped the challenge of building a new satellite thruster that exploits all the benefits of this unique Australian technology - and the Europeans are impressed enough to want to test it in their vacuum chamber," says Professor Boswell.

"We've put together a really powerful Australian team to deliver it."

The research addresses National Research Priority three - frontier technologies for transforming industry.