ISS Spacewalk 12/21, 12/23 and 12/25 ISS Expedition 38 Spacewalk 12/21, 12/23 and 12/25 12/21, Saturday 6:15 a.m. - ISS Expedition 38 Spacewalk Coverage (spacewalk scheduled to begin at 7:10 a.m.) 12/23, Monday 6:15 a.m. - ISS Expedition 3…