ESA’s Proba-1 minisatellite was launched two decades ago, on October 27, into orbit. It has completed 20 years.

Key Points

• The minisatellite remains fully operational for 20 years.
• It is the oldest serving Earth observing mission of the agency.
• Proba-1 is roughly the size of a hotel fridge. It hosts two Earth-observing instruments together with several technological firsts.
• Probe 1 is the first in ESA’s family of ‘Project for On-Board Autonomy’ missions.
• It started life as a technology demonstration satellite and later became an Earth observation mission.
• It is highly automated and introduced several mainstream technologies to space, such as, lithium-ion batteries, use of star trackers for gyro-free attitude control and gallium arsenide solar panel as well as ESA-developed ERC-32 microprocessors that run its flight computers.