new P4 array deployed by STS-115 to rotate and track the sun. STS-116 was the last STS mission scheduled for launch from pad 39B. The pad will be refitted for upcoming Ares I launches. The crew of STS-116 consisted of five rookie astronauts. Only Mission Commander Mark Polansky (2) and Mission specialist Robert Curbeam (3) had previously flown in space. Robert Curbeam became the first astronaut to make four EVAs during the same mission. This was the first mission with two African-American crewmembers. Mission notes As one of the main goals of STS-116 was to exchange ISS Expedition 14 crew members, the crew of STS-116 changed mid-flight. ISS Flight Engineer Sunita "Suni" Williams was part of the STS-116 crew for the first portion of the mission. She then replaced ISS Flight Engineer Thomas Reiter on the Expedition 14 crew and Reiter joined the STS-116 crew for the return to Earth. Final Assembly Power Converter Unit mission for Discovery During planned orbiter upgrades that took place subsequent to this mission, Discoverys Assembly Power Converter Units (APCUs) were removed and replaced with the shuttle-side components of the Station-Shuttle Power Transfer System (SSPTS). The APCUs converted 28VDC orbiter main bus power to 124VDC, compatible with the ISS's 120VDC main bus power. During initial station assembly missions, orbiter APCU power was used to augment the power available from the Russian service segment. With the operation of permanent main electrical systems (e.g. P4 array and SARJ, MBSUs, DDCUs, Ammonia cooling systems), orbiter power was no longer needed by the ISS. After STS-118, Discovery and Endeavour drew power from the ISS, although Atlantis was never upgraded with the SSPTS. This system slowed the orbiters' consumption of hydrogen and oxygen used by their onboard electricity-generating fuel cells. The hydrogen and oxygen supplies, stored cryogenically in tanks aboard the orbiter, limited the duration of Space Shuttle missions. As a result of the changeover to SSPTS, Discovery and Endeavour gained approximately 50% of the time that would have been spent docked otherwise. This resulted in 2–4 extra days for each ISS-docked mission. Section 8.5, page 66 AFT FLIGHT DECK PAYLOADS SWITCH LIST FOR HANDOVER Mission payloads The primary payload for the STS-116 mission was the P5 Truss segment of the International Space Station. The shuttle also carried a Spacehab Logistics Module to resupply the ISS, and an Integrated Cargo Carrier with four sub-satellites, which were deployed after undocking from