Today Bradford and TNO successfully conducted a test firing of a Cool Gas Generator (CGG) onboard the PROBA2 satellite. Team members of both Bradford and TNO were present on-site at the ESA ground station in Redu, Belgium, to coordinate and review the test results in real-time.

The nitrogen gas produced by the CGG, increased the pressure inside the spacecraft propellant tank from 6.2 bar to 20.3 bar. Each CGG aboard PROBA2 delivers 43 grams of >99% pure nitrogen gas at ambient temperature. The Cool Gas Generator is a unique technology that produces pure gas through decomposition of a solid material, while the gasses leave the gas generator at ambient temperature.

The four CGGs are part of the Cool Gas Generator Experiment (COGEX), a technology demonstration payload aboard PROBA2 developed jointly by Bradford and TNO in the 2004/05 timeframe. In this consortium Bradford acted as the industrial partner, responsible for the overall system design, manufacturing and verification aspects, while TNO contributed the key CGG technology including research, manufacturing and testing of the flight CGGs. The COGEX program was nationally funded by the Dutch space agency NIVR (now Netherlands Space Office, NSO), enabling the qualification and on-orbit demonstration of the CGG technology for spaceflight applications.

COGEX is outfitted with pressure and temperature monitoring equipment, reporting the results of the on-orbit performance. A Bradford Standard Accuracy Pressure Transducer (SAPT) fulfills the pressure monitoring role in the system. COGEX interfaces with a xenon resistojet experiment contributed to PROBA2 by Surrey Satellite Technology Ltd. in the UK, providing nitrogen refills to the propellant tank, allowing additional delta-v capabilities and testing of the resistojet thruster at various xenon-nitrogen mixtures.


Today’s successful test is key to the further development and applications of this technology, demonstrating 11-year post-delivery and 7-year on-orbit lifetimes. This is the third time a CGG has been operated on board of PROBA2 since earlier on-orbit tests in August 2011 and October 2012. A fourth and final CGG test is planned for near the end-of-mission date of PROBA2, which is still undecided.