The Robotic Refueling Mission is a NASA technology demonstration mission with equipment launches in both 2011 and 2013 to increase the technological maturity of in-space rocket propellant transfer technology by testing a wide variety of potential propellanttransfer hardware, of both new and existing satellite designs. The first phase of the mission was successfully completed in 2013. The second phase experiments continued in 2015.
History
Development
The Robotic Refueling Mission was developed by the Satellite Servicing Capabilities Office at the Goddard Space Flight Center. It was planned to demonstrate the technology and tools to refuel satellites in orbit by robotic means. After the proof of concept, the long-term goal of NASA is to transfer the technology to the commercial sector. RRM was designed with four tools, each with electronics and two cameras and lights. Additionally, it had pumps and controllers and electrical systems such as electrical valves and sensors. The RRM payload was transported to the Kennedy Space Center in early March 2011, where the GSFC team performed the final preparations for space flight. Once up on the International Space Station, RRM was planned to be installed into the ELC-4. The Dextre robot was planned to be used in 2012 and 2013 during the refueling demonstration experiments.
NASA successfully completed the phase 1 demonstration mission in January 2013, performing a series of robotic refuelings of satellite hardware that had not been designed for refueling. An extensive series of robotically-actuated propellant transfer experiments on the exposed facility platform of the International Space Station were completed by the RRM equipment suite and the Canadarm/Dextre robotic arm combination. The experiment suite included a number of propellant valves, nozzles and seals similar to those used on a wide variety commercial and U.S. government satellites, plus a series of four prototype tools that could be attached to the distal end of the Dextre robotic arm. Each tool was a prototype of a device that could be used by future satellite servicing missions to refuel spacecraft in orbit. RRM is the first in-space refueling demonstration using a platform of fuel valves and spacecraft plumbing representative of most existing satellites, which were not designed for refueling.
Phase 2
Phase 2 of the RRM mission began in August 2013 with the launch of the phase 2 RRM hardware to the ISS aboard the Japanese H-II Transfer Vehicle 4 for test operations expected to be carried out in 2014. The Phase 2 hardware complement consists of:
In February 2014 the ground-based 'Remote Robotic Oxidizer Transfer Test' transferred nitrogen tetroxide via a standard satellite-fueling valve at the satellite fuelling facility, Kennedy Space Center, using a robot controlled remotely from the Goddard Space Flight Centre, away in Greenbelt, Maryland. On March 26, 2015 The RRM On-orbit Transfer Cage was loaded into the Kibo airlock and picked up by the JEM Robotic Arm who handed it off to Dextre for installation on the main module. On April 30, 2015 The RRM On-Orbit Transfer Cage was installed on the main module and the Phase 1 hardware was removed and placed in the cage for disposal on HTV-4. The experiment was then activated that same day. February 2016 the Phase 2 experiment was deactivated and all fuel and cooling lines were turned off in preparation for disposal of the RRM payload and its fuel on SpaceX Dragon CRS-10. On February 23, 2017 The main module of the RRM experiment and the Phase 2 hardware were removed and stored in the trunk of SpaceX CRS-10 for disposal and the STP H5 experiment with Raven was activated beginning Phase 3.
Phase 3
With the completion of Phase 2 Phase 3 testing is underway with the launch of Raven on CRS-10. The new Phase 3 module was delivered to the station on December 8, 2018 on SpaceX CRS-16 and installed on the ELC 1 on December 19, 2018. Zero boil off storage of cryogens was demonstrated for 4 months, but following a cryocooler failure the methane was vented in April 2019. Remaining tests are still planned; these include plugging a fuel nozzle into a refuelling port.
