Small pellicle laser interferometers for the space optics testing

Simple and small laser interferometers for the space optical systems testing are discussed. Interferometer consists of a lens in front of the gas laser, flat pellicle beamsplitter, a tiny flat reference mirror, and optics under test. The interferometer is not affected by displacements and the tilts of the lens, the beamsplitter, and the reference flat mirror, that it is especially recommended for the space optics testing on the orbit.