What is a PMD?
Propellant Management Devices, or PMDs, are static all metal structures inside spacecraft propellant tanks that use surface tension to ensure gas free liquid delivery to the tank outlet. They can be made entirely from titanium allowing their use in the most corrosive propellants. With no moving or deforming parts, they are inherently reliable.
Who Needs a PMD?
Anyone who needs liquid access or liquid control in space. PMDs are found in many satellites, solar system probes, rockets, and the Space Shuttle. They are used mostly for propellants but can be used in water systems, thermal systems, cryogenic systems and, in fact, in any space bound liquid system.
Why Use a PMD?
PMDs can be made completely from titanium (or from any suitable solid). This makes them compatible with any liquid and very lightweight - unlike the alternatives such as rubber bladders. Plus PMDs are much more reliable since they have no moving parts.
How do I get a PMD?
Each PMD is custom designed for the mission. First, the spacecraft or spacecraft subsystem builder must define the PMD requirements in a specification (PMD Technology can help). Second, PMD Technology will work with the customer to custom design the optimum PMD solution; trading cost, weight, reliability, and performance.