October 30, 2009 Vol. 2, Issue 10
The Swedish Space Corporation is counting down to the first launch of its green propulsion satellite technology.
The MANGO and TANGO satellites, part of the Prisma mission, will demonstrate the use of a high performing green propulsion (HPGP) system running on a “green” propellant. The development of the Prisma propellant is one among several of the global efforts to develop a safer, less hazardous alternative to the standard spacecraft propellant hydrazine.
Operating under contract with the Swedish National Space Board (SNSB) and the European Space Agency since 1997, the Swedish Space Corporation and ECAPS have developed a “green” ammonium dinitramide (ADN)-based propellant capable of safe storage — a monopropellant — called LMP-103S. The propellant is a blend of ADN, ammonia, and methanol dissolved in water acting as the oxidizer, stabilizer, and fuel components respectively. The HPGP system contains a single 4.5-liter diaphragm-type propellant tank, and two monopropellant thrusters, and commercial off-the-shelf (COTS) components.
After testing for safety, performance, compatibility, and stability, LMP-103S earned a UN transport classification of 1.4S (meaning the material may be at risk for a moderate fire, but not a blast or fragment). It is insensitive to hammering and friction, much less toxic than hydrazine, requiring only normal protective work clothing, and is capable of long-term storage of up to 20 years. Additionally, the propellant is compatible with the propulsion system’s COTS components.
The HPGP system offers an improved density impulse of 25-30 percent over hydrazine. In comparison with hydrazine and bipropellant systems, the HPGP system falls between the two regarding the ability to change a spacecraft’s velocity without increasing its complexity or the cost of the overall system.
MANGO and TANGO are the satellites scheduled to demonstrate their formation flying and rendezvous capabilities powered by the HPGP system. Funded by the SNSB with support from the German Aerospace Center (DLR) and French space agency (CNES), MANGO will execute a series of long- and short-range maneuvering experiments around the TANGO satellite which does not have maneuvering capability.
Future European Earth-like planet finding missions like Darwin and the Aurora Mars missions may benefit from the findings of the MANGO and TANGO satellite system demonstration, which is scheduled to launch from a Russian launch pad in February 2010.