Search results
Results from the WOW.Com Content Network
Reaction control systems are capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow control of rotation (roll, pitch, and yaw). [2] Reaction control systems often use combinations of large and small thrusters, to allow different levels of response.
A thruster is a spacecraft propulsion device used for orbital station-keeping, attitude control, or long-duration, low-thrust acceleration, often as part of a reaction control system.
The second passive system orients the satellite along Earth's magnetic field thanks to a magnet. [7] These purely passive attitude control systems have limited pointing accuracy, because the spacecraft will oscillate around energy minima. This drawback is overcome by adding damper, which can be hysteretic materials or a viscous damper.
In practice, if A and B interconvert with overall rate constants k f and k r, then for most practical purposes, the change in composition becomes negligible after t ~ 3.5/(k f + k r), or approximately five half-lives, and the system product ratio can be regarded as the result of thermodynamic control. In general, short reaction times favour ...
A small reaction wheel viewed in profile A momentum/reaction wheel comprising part of a high-accuracy Conical Earth Sensor to maintain a satellite's precise attitude. A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through conservation of angular momentum. [1]
The control torque for a launch vehicle is sometimes provided aerodynamically by movable fins, and usually by mounting the engines on gimbals to vector the thrust around the center of mass. Torque is frequently applied to spacecraft, operating absent aerodynamic forces, by a reaction control system, a set of thrusters located about the vehicle ...
Bell designed and built the Reaction Control system for Project Mercury's Redstone command module and a similar system was incorporated into the North American X-15 spaceplane. NASA selected Bell to develop and built the Lunar Landing Research Vehicle (LLRV) , three of which were built in the early 1960s to train the Apollo astronauts to land ...
Diffusion control is more likely in solution where diffusion of reactants is slower due to the greater number of collisions with solvent molecules. Reactions where the activated complex forms easily and the products form rapidly are most likely to be limited by diffusion control. Examples are those involving catalysis and enzymatic reactions.