Ion Thruster

Spaceship Engine Future









Ion engine - a kind of electric rocket motor. His body is working ionized gas (Xenon or caesium).

The principle of the engine is the ionization gas and disperse its electrostatic field. In doing so, due to high relative to the mass of charge, it becomes possible to disperse the ions to very high speeds (above 200 km / s, compared with 3-4.5 km / s from chemical rocket engines). Thus, the ion engine can reach very high specific impulse. This helps considerably reduce the flow of reactive mass of ionized gas, compared with the flow of reactive mass in the chemical missiles, but much more expensive energy. Lack engine in its current implementations - very little traction (about tenth of a Newton). Thus, it is not possible to use ion engine to start with the planet, but on the other hand, being in open space, with enough work long engine is possible to disperse the spacecraft reach speeds up to now any other types of existing engines (except for solar sails).

The existing implementations to support the work of the engine used solar panels. But to work in outer space this way is unacceptable. Therefore, in the future for these purposes is planned to use nuclear installations.
ION ENGINE - 30.09.2003 on Saturday from Kourou launch vehicle "Ariane 5" has been successfully bred in outer space research station European Space Agency SMART 1. The satellite was created by the order of ESA (European Space Agency, European Space Agency), the Swedish Space Corporation with the participation of nearly 30 contractors from 11 European countries and the United States. Total project cost amounted to 110 million euro.

SMART 1 - ESA first automatic station for the study of the Moon. At the same time, a unique new type of research station, first in the new programme, called ESA Small Missions for Advanced Research in Technology. In implementing the programme is scheduled approbation of a number of new technologies, for example, the link in the Ka-band and laser communications, autonomous navigation and much more.

When sufficiently large quantities of equipment, SMART 1 differs small weight (370 kg, including the scientific instruments - 19 kg) and compact. For slozhennymi solar panels it is a rectangle of in the meter. Cost SMART 1 approximately every five less than the typical interplanetary station ESA. But the most important feature of the new spacecraft that for the first time in the history of space ion engine will be used as a guideline. Plans ESA - two more apparatus, equipped with ion propulsion. This BepiColombo for the study of Mercury, and Solar Orbiter - to study the Sun.

Established on 1 SMART ion engine consumes 1350 watts of electricity produced solar panels, and develops cravings 0.07 in Newton, which is about the weight of postal cards. The working substance serves xenon (82 kg of fuel). In doing so, to enter the elliptical polar orbit around the Moon station took 16 months. Withdrawal SMART 1 on the design orbit represented a complex multistage process, which consists of several stages.

Strictly speaking, ion engines have already been installed on the spacecraft - in recent years, in particular, the research station at NASA Deep Space 1 (DS 1) and the pilot geostationary satellites connection ESA Artemis. In the latter case, due to the presence on board of ion engines, kazan finally managed to salvage the lost satellite at the cost of millions of dollars.

Work abnormal upper stage launcher Ariane 5, to place in orbit a satellite Artemis, has resulted in the orbit of Artemis was significantly lower than estimated. Usually, this leads to the loss of the satellite. If he poses a threat to other spacecraft, its top (heavy equipment), or "burning" in the atmosphere. But Artemis escaped this sad fate.

Due to the urgent measures taken and the price of spending almost the entire stock of chemical fuel available on board the satellite was able to convert circular orbit at a height of 31 thousand km. But after that it was necessary to translate estimated at Artemis geostationary (a height of about 36 thousand km). Then it was decided to take four ion engines installed on board in pairs. They originally were intended for the management orientation (inclination) satellite. What would make the transition vector propulsion engines had been sent perpendicular to the orbital plane. But to save the apparatus he had to give impetus to the orbital plane, and thus translate into higher geostationary orbit. Artemis was required to turn 90 degrees in relation to its normal orientation.

Difficult rescue operations, demanded elaborate "on the fly" new strategy, new management regimes and the functioning of on-board satellite communications equipment. It took 20% of the modified onboard software. Yet the operation was very successful. On its complexity evidenced by the fact that only for reprogramming the on-board control system required carregar from Earth modified software blocks totalling 15 thousand words. It was the most ambitious operation reprogramming from the ground telecommunications satellite.

Despite the modest power (only 15 millinyuton) Artemis was "karabkatsya" calculated orbit at up to 15 kilometres per day. The entire rescue operation took 18 months. January 31, 2003 Artemis was exactly where it should be even half a year ago. The world's first rescue operation, the outcome of which is entirely dependent on the reliability of ion engines and concerted action of people on Earth, was successful. Sputnik, believes hopelessly lost, proceeded to normal work.

By its very design the main engine of SMART 1 differs significantly from the engines installed on the DS 1 and Artemis. In the case of the last two apparatuses, to accelerate the ions used grill filed with the potential to it (the so-called gridded ion engine). In contrast, the SMART 1 is equipped with ion engine Hall, which is significantly different in their construction. An important advantage of engines Hall Effect is the lack of lattice, are subject to constant bombardment of high ions, resulting in its rapid degradation occurs.
Regarding the other characteristics of ion engines of different structure, the situation is not so obvious. In general, engines with a lattice provide more specific impulse and spend about twice as less fuel (a working body) than engines Hall. However, the engines allow Hall to develop greater specific cravings for the same electricity consumption. Both structures are its advantages and disadvantages, and choice of preferred option in each case depends on the nature of challenges facing the apparatus, and from its energy capabilities.