Hermes was envisaged to be launched using the Ariane 5, replacing the upper stage of the latter during such missions, and would have detached from the launcher towards the latter part of the ascent. Prior to 1986 redesign, "Hermes" is a single spaceplane, containing (from front to back) crew compartment for 6, airlock, unpressurized cargo hold, and service module. After 1986, due to Challenger incident, it was substantially redesigned. The crew cabin is reduced to only carry 3 astronauts, with the cargohold now pressurized and cannot carry/bring back satellites. "Hermes" now consisted of two separate sections: the vehicle itself and a cone-shaped Resource Module, the latter was to contain a docking mechanism and have been attached to the vehicle's rear, and would have been detached and discarded prior to re-entry. Only the crewed vehicle would re-enter Earth's atmosphere and be re-used, both the Resource Module and the launcher would be expended. When operated in conjunction with Hermes, the Ariane 5 would have had its upper stage entirely replaced to accommodate both the space plane and an adaptor to mate the vehicle with the main cryogenic stage, the equipment bay of the launcher would also be absent while the space plane itself would perform all guidance and control functions. The development and configuration of the Ariane 5 was strongly influenced by the requirements of Hermes, such as the extra aerodynamic loads that it would have imposed along with the elevated reliability factor of 0.9999, while retaining minimal impact on the launcher's commercial competitiveness on non-Hermes missions.