Optical arrangement for space-borne light-pulse interferometry employing a BEC and associated diffraction processes. a, b After release of the multi-component rubidium BEC two light beams, A and B, with different frequencies νA and νB, and intensities travel in opposite directions parallel to the atom chip and generate a moving optical lattice driving Bragg processes, which coherently transfer momentum to the atomic wave packet along the x-direction (b). Two additional light beams tilted by two degrees emerge due to reflections of the beams A and B on the optical viewports. c Their interference with the lattice beams gives rise to a traveling spatial intensity modulation in the y-direction modifying the BEC wave function as well as inducing weak double-Bragg processes in x-direction (not shown). d In addition, the light beams are diffracted at the atom chip and the arising interference modulates their intensity in y-direction. The various effects of the light pulses on the multi-component wave packet are detected by a CCD-camera recording the shadow of the BEC irradiated by light (green circle) from the z-direction. Earth gravity pulls along the x-direction during space flight, and along the x–z diagonal on ground.