Astronauts complete bonus objectives in first in series of AMS repair spacewalks Spaceflight NowAstronauts experienced reverse blood flow and blood clots on the space station, study says CNNAstronauts Are On a Spacewalk Right Now to Repair a Crucial Dark Matter Experiment GizmodoAstronauts on complex spacewalk prepare AMS cosmic ray detector for repair collectSPACE.comWatch live: Astronauts start spacewalk series to fix cosmic ray detector msnNOWView full coverage on Google News