The scientific basis of the astrometric program for the project ISSO, has been subjected to the support of the main above mentioned problem. Inclusion of astrometric, photometry and celestial mechanics tasks allows to expand and to develop the scientific importance of the project and to raise efficiency of the project as a whole. It is offered to concentrate the program on star parallaxes determination and determination of distances of the Solar System bodies by synchronous observations. The possibility to support the microlensing events observations is proved. The arrangement concept is exposed.
 Grigoryev V.M., Solar Phys. 1993. V. 148. P. 386.