Keystone Engineering developed a unique proprietary technology for the near-net spin-forming of domes and hemispheres for propellant and pressurant storage. The near-net spin-forming of these components allows for ultra-thin walled, close tolerance machining in less time and at lower cost than components made from forgings. This technology is available for aluminum, titanium and Inconel applications. Our storage assemblies utilize all metal or elastomeric propellant management technologies.
Keystone designs and manufactures Propellant Management Devices (PMD) that utilize the surface tension of the propellants and its interaction with the surfaces of internal structures to passively deliver propellants in microgravity environments. Keystone PMD designs utilize combinations of metal sponges, traps, troughs, vanes, wicks, and other structures to provide proper liquid propellant delivery. PMDs are designed for each specific application taking into account the many conditions and loads experienced including fueling, ground handling, launch, orbital insertion, and station keeping.
Keystone produces spacecraft propellant tanks with positive expulsion devices (PED) to provide propellants under operational environments or CG requirements that exceed the capabilities of surface tension PMDs. One type of PED is the elastomeric bladder. Keystone produces tanks with elastomeric bladders in several mechanical and material configurations to allow an optimal method of providing propellants for specific missions.
In some missions the best solution is a PED using a metal diaphragm. Keystone Engineering produces propellant tanks with metal diaphragms that can be optimized based on mission requirements including cyclic life, center of mass stability, and material compatibility.
With a full range of surface tension PMD and PED capability, Keystone Engineering can design optimal propellant storage and delivery systems for every requirement set.
Keystone possess the complete capability to design, produce and qualify pressurant and xenon propellant tanks using advanced composite materials and tank liner fabrication capabilities. This enables Keystone to offer a high value, ultra flight weight solution to or customers propellant & pressurant storage needs. Our capabilities also support other COPV producers by providing advanced liner fabrication using titanium, aluminum, and Inconel materials. Our ultra-thin walled, welded liner technology makes best use of our advanced spin-form, machining and “state of the art” welding expertise.
Keystone Engineering is at the forefront of demisable propellant tank design and implementation. Modern Earth-orbiting spacecraft design must take into account the risk from orbital debris at its end of useful life. One major obstacle to reducing this risk has been the robustness of traditional propellant tanks which usually survive re-entry relatively intact. International agreements and agency standards such as NASA Technical Standard 8719.14 require limiting the risk of human casualty. Methods generally employed to meet these requirements with spacecraft using conventional propellant tanks has been to intentionally shorten mission life by de-orbiting the spacecraft while still fully functional. Using demisable propellants tanks, a spacecraft can be designed to meet the orbital debris requirements and remain in-orbit during its entire life operational life. This increased life represents a significant increase to the value of a spacecraft and its mission.In February of 2014, NASA’s Global Precipitation Satellite was launched with the first propellant tank built for demisability. The novel tank used Composite Overwrap Pressure Vessel (COPV) technology and Keystone Engineering’s aluminum liner and aluminum surface tension PMD. Since the tank liner was delivered for composite overwrap in 2011, Keystone has developed and patented new technologies for producing aluminum PMDs. The new designs have improved contamination resistance and are compatible with all chemicals used in spacecraft processing.