Procyon
The University of Tokyo and JAXA joined forces to build a spacecraft weighing just 70 kilograms. This small probe measured approximately 60 centimeters on each side, resembling a compact cube. Engineers designed it as a low-cost secondary payload for the Hayabusa2 mission. The project aimed to test new technologies without consuming massive budgets. A single tank held 2.5 kilograms of xenon gas at launch. This same reservoir fed both the main ion engine and eight attitude control thrusters. Such integration represented a novel subsystem for spaceflight testing.
the 3rd of December 2014 marked the moment PROCYON lifted off alongside its larger companion Hayabusa2. The launch occurred precisely at 13:22:04 Japan Standard Time. After separation from the carrier rocket, the probe entered a heliocentric orbit around the sun. Mission planners intended for this path to eventually lead toward an asteroid flyby in 2016. The spacecraft carried specific instruments including a small telescope for navigation. It also included a Lyman-alpha imaging camera for scientific observation. These tools would later prove vital despite the mission's eventual failure.
the 22nd of February 2015 saw the ion engine start operation with promising initial results. The system delivered 330 micro-Newtons of thrust instead of the designed 250 micro-Newtons. Engineers hoped this extra power would help adjust the orbit effectively. However, the engine failed completely on the 10th of March 2015. Attempts to restart the malfunctioning unit proved unsuccessful throughout the following months. This single mechanical breakdown doomed the planned asteroid encounter scheduled for 2016. The delta-v budget of about 500 meters per second could not be utilized as intended.
the 3rd of December 2015 brought PROCYON close to our planet during an uncontrolled flyby. The spacecraft passed Earth without making any controlled orbit change due to the earlier thruster failure. Contact with the probe was lost shortly after this gravitational swing-by event. Mission controllers had hoped to use 20% of the xenon propellant for initial corrections. They planned to use the remaining gas between the Earth and target asteroid encounters. A controlled distance of 30 kilometers remained impossible to achieve without functional propulsion.
Despite the mission's operational end, PROCYON captured significant scientific data before losing contact. The Lyman-alpha imaging camera observed comet 67P/Churyumov, Gerasimenko to map its coma structure. More importantly, the instrument recorded the first complete image of Earth's geocorona. These observations confirmed that the geocorona possesses north-south symmetry for the first time ever. The specific impulse of 1000 seconds allowed the craft to gather these measurements effectively. This achievement provided valuable insights into the outer atmosphere surrounding our home planet.
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Common questions
Who built the PROCYON spacecraft?
The University of Tokyo and JAXA joined forces to build the spacecraft. The probe weighed 70 kilograms and measured approximately 60 centimeters on each side.
When did the PROCYON launch occur?
The 3rd of December 2014 marked the moment PROCYON lifted off alongside its larger companion Hayabusa2. The launch occurred precisely at 13:22:04 Japan Standard Time.
What caused the failure of the PROCYON mission?
The ion engine failed completely on the 10th of March 2015 after operating with promising initial results. This single mechanical breakdown doomed the planned asteroid encounter scheduled for 2016.
How close did PROCYON fly by Earth during its uncontrolled pass?
The 3rd of December 2015 brought PROCYON close to our planet during an uncontrolled flyby. A controlled distance of 30 kilometers remained impossible to achieve without functional propulsion.
What scientific data did the Lyman-alpha imaging camera capture before contact was lost?
The instrument recorded the first complete image of Earth's geocorona. These observations confirmed that the geocorona possesses north-south symmetry for the first time ever.