The successful Project Mercury flight test program placed great emphasis on the Mercury Capsule Reaction Control System on board the spacecraft. Design of the redundant, automatic and manual, subsystems is discussed, as well as the variety of operating modes which were available for astronaut selection.
The hydrogen peroxide rocket system afforded challenging design problems in the areas of positive expulsion devices for the propellant tanks, solenoid valving, and catalyst beds for the thrusters. Several important design changes were effected during the course of the program as a result of experience gained through both development and flight testing. During the course of the orbital Mercury spacecraft flights, minor discrepancies occurred in the reaction control system operation. These discrepancies were in no way deleterious to the success of the mission; however, they revealed the need for minor redesign to enhance system reliability.
The personal reaction of the astronauts to the performance and handling of the spacecraft attitude controls is discussed, along with system changes which were effected for each particular manned space flight. The design lessons yielded from Project Mercury will enable the designer of future manned spacecraft reaction control systems to provide greater durability, performance, and reliability in this area.