Polish Thruster for Space Probes
March 3, 2014
A prototype of the first Polish plasma thruster for space probes and satellites has been successfully tested in conditions similar to those in space at a European Space Agency (ESA) laboratory in Nordwijk in the Netherlands.
The thruster—which is a device used to power space probes and satellites—has been developed by a group of scientists from the Institute of Plasma Physics and Laser Microfusion (IFPiLM ) in Warsaw and is expected to be cheaper in use than existing devices.
“During the tests, the thruster worked long enough to measure important parameters such as thrust,” said the team leader, Jacek Kurzyna, Ph.D., of the Institute of Plasma Physics and Laser Microfusion. “It’s possible to speak of the first step on the road to success. The problem-free launch of the device surprised even experienced ESA staff. Normally the first run requires a careful selection of the operating parameters of the system, which are extremely difficult to determine on an a priori basis.”
The device is a type of plasma electric propulsion Hall thruster, the researchers say. Such thrusters are successfully used in space, where they help keep satellites on the desired orbit or change their position. They are also used as means of propulsion in long-range probes. Due to their relatively low fuel consumption, such thrusters are serious competitors to traditional rocket engines. A space rocket engine needs roughly 10 times more fuel than a plasma thruster for the same mission, according to the Warsaw researchers.
The thruster weighs four kilograms and is cylindrically shaped. It has a diameter of 10 cm and is 12 cm long. Its maximum operational capacity is about half a kilowatt.
The device developed by the Polish scientists generates enough thrust to work on satellites weighing up to 100 kg.
The institute’s Serge Barral, Ph.D., said, “The SMART-1 probe sent into orbit around the Moon by the ESA was fitted with a xenon thruster with a capacity of less than 2 kW. It was capable of increasing the probe’s speed by about 3.6 kilometers per second. Our thruster could also be used to power small space probes.”
The Warsaw researchers say they aim to build a Hall thruster that will be cheaper to run than those currently used. They plan to achieve this by using krypton instead of xenon as the power source. Krypton is up to 10 times cheaper than the most commonly used xenon gas, according to the researchers.
When designing the device, in order to reduce costs and decrease the number of prototypes, the researchers conducted a series of computer simulations. These enabled them to assess what configuration of components would make it possible to achieve the highest efficiency. For the simulations they used a program written by Barral, one of the thruster’s designers. The calculated efficiency of the prototype is consistent with the preliminary results of tests performed at the ESA laboratory and reaches 50 percent in optimum conditions, according to the researchers.
The first step—building and launching the prototype thruster—has already been carried out. With the first tests behind them, the researchers are now waiting for the full results, which are being compiled by ESA experts, and are meanwhile pressing ahead with work on the next prototype.
“During the two-week experimental session, we carried out several measurements. We collected a lot of data,” said Jan Miedzik, a participant in the project.
Dariusz Dani³ko, a team member responsible for the numerical modeling of the magnetic field in the Hall thruster, said, “The first tests of the prototype system showed where modifications are needed. The most important and most difficult-to-design system component – the magnetic circuit—worked without problems, so we will try to achieve the same configuration in the next prototype.” This next prototype is expected to be tested at the ESA laboratory next year.
The research conducted by the Polish scientists is expected to help reduce the operating costs of satellites and space probes—hardware that we all benefit from on an everyday basis, often without realizing it. Devices mounted on satellites are used for accurate weather forecasting, television broadcasting and telephone call transmission. Moreover, the GPS navigation system is based on satellites. Data and call transmission over long distances is cheaper with satellites than terrestrial connections, the Warsaw researchers say.
The design and construction of the first version of the electric Hall plasma thruster was financed by the Institute of Plasma Physics and Laser Microfusion. The tests at the ESA laboratory and work to build another prototype are being financed by the Krypton Large Impulse Thruster (KLIMT) project, which is being carried out under an agreement between Poland and the ESA.
The prototype of the first Polish plasma thruster is already operational. For the time being, it is being used for scientific research, but in the future commercial production is planned with the participation of industrial partners.
Meanwhile, the same research team is working on another, much smaller thruster, which in the future will be used on small probes or satellites including the Polish LEM satellite.