Two Russian cosmonauts and a U.S. Navy test pilot will buckle into custom-molded seats inside a Soyuz spaceship Wednesday, undock from the International Space Station and head for a parachute-assisted landing in Kazakhstan to close out a 167-day space voyage.

A Proton rocket lifted off from the Baikonur Cosmodrome in Kazakhstan with the Spektr-RG X-ray astronomy mission at 1230:57 GMT (8:30:57 a.m. EDT) Saturday.

A commercial mission developed by the Japanese company Astroscale rocketed into space on a Russian Soyuz launcher Monday with 37 other payloads, ready to kick off an orbital “dance” with two small spacecraft demonstrating how satellite sweepers might one day drag junk out of orbit.