The problem of pollution of outer space by space debris objects (SDO) is now becoming more and more urgent, as mankind steadily increases the rate of space exploration. At the end of their active life, spacecraft (SC) fail and lose controllability. As a result, there is an increased risk of collision between the failed spacecraft and functioning ones. To prevent this, it is necessary to remove inactive SC out of the orbit region under protection. One of the promising ways to remove spent spacecraft that became space debris objects (SDO) is to use a service spacecraft equipped with an ion injector with a weakly diverging ion beam. Such beam generated by the ion injector acts on the SDO and removes it to the disposal orbit or dense atmosphere. It should be taken into account that the efficiency of energy and momentum transfer from an ion beam to SDO depends on the ion beam divergence angle and ion energy. The ion beam divergence depends on the electric potential distribution on electrodes and on the profile of holes in the electrodes. A detailed study for a single aperture cell of the ion extraction system shows that the ion beam divergence depends essentially on the emission electrode hole profile.

The main point of presented study was the geometry numerical simulation for the holes in electrodes of ion injector, which provides the specified characteristics that meet the requirements to its use for SDO removing. As a part of the work on the development of a full-size onboard injector, a small-sized prototype with the electrodes working part diameter of 100 mm was designed for studying the IES operation. According to the results of experimental study for a small-sized electrode model as a part of a laboratory injector, the IES normalized perveance was 1.731∙10^-8 А/сm² V^3/2, which corresponds to the minimum half-angle of divergence of 1.9⁰. The obtained characteristics make it possible to act on SDO from the distance of 40-60 m. According to our calculations, the beam ion current of 0.5 A is sufficient to remove most SDO. Based on this requirement, the IES geometry and the optimal electrode hole profile were determined, which will allow to increase the ion beam focusing to the minimum divergence half-angle of 1.14⁰ and the corresponding normalized perveance of 1.47∙10^-8, А/(cm²∙V^3/2). As part of the work, it is planned to test the required IES geometry of the ion injector.

This work was carried out as part of the implementation of the Federal Target Program "Research and Development in Priority Directions for the Development of the Russian Science and Technology Complex for 2014 - 2020" (Agreement No. 05.604.21.0211. Unique identifier of the agreement: RFMEFI60419X0211).