In such areas as space rescue, inspection and repair of parent and satellite spacecraft, personnel and cargo transport, and space structure erection.
In such areas as space rescue, inspection and repair of parent and satellite spacecraft, personnel and cargo transport, and space structure erection. The addition of manoeuvring aids to such EVA tasks is expected to reduce crew fatigue and stress, cut time requirements offset pressure suit mobility limitations, and facilitate attitude orientation ad stabilization.
The astronaut manoeuvring equipment of Experiment M509 consists of two jet-powered sides for mane ???vering in a zero gravity space environment. These include a back-mounted hand-controlled unit teamed with the Automatically Stabilized Manoeuvring Unit (ASMU), or backpack, and a hand-held manoeuvring unit (HHMU). The backpack contains a rechargeable/replaceable high pressure nitrogen propellant tank which supplies both units, and is therefore worn whether maneuovering by ASMU or HHMU. The electrical systems within the backpack are powered by a rechargeable/replaceable battery. The astronaut dons the backpack over either a pressurized space suit or flight coveralls using a quick release har???ess similar to that used for parachutes.
The ASMU is maneuovered in six degrees of freedom (X, Y, and Z axis translation, and pitch, yaw and roll) by means of 14 fixed thrusters located in various positions on the backpack. Control of the thrusters is imparted by two hand-controllers mounted on arms extending from the backpack. The controllers are identical to those used in the Apollo spacecraft. The left hand controls linear translation and the relight hand, using an aircraft-type hand grip, controls pitch, yaw, and roll. There are three selectable modes of ASMU control: (1) DIRECT, whereby the appreciates rotation and translation thrusters are commanded in direct response to visual cues, (2) RATE GYRO, whereby an attitude hold feature and proportional rate commands are added to the DIRECT mode capability by means of rate gyro-sensed motions, and (3) CMG (Control Moment Gyro), whereby an attitude hold feature is added to the DIRECT mode capability by means of the momentum exchange caused by torquing an appropriate combination of pitch, yaw, or roll CMG's. In this mode, the momentum exchange rather than thruster firings causes attitude changes.
The HHMU is a simple, small, lightweight, completely manual device. The unit compresses and hand grip and controls for a pair of tractor thrusters and a opposing single pusher thruster; the assembly is connected to the ASMU propellant