This month marks the 30th anniversary of the launch of the first of Canada’s RADARSAT synthetic aperture radar satellites.

RADARSAT 1, Canada’s first Earth observation satellite, was launched into orbit on 4 November 1995 from Vandenberg Air Force Base in California.

The spacecraft had a Sun-synchronous (dawn-dusk) orbit at an altitude of 798 km and an inclination of 98.6°, completing 14 orbits per day and having a revisit cadence of 24 days. It carried a C-band radar.

The highly successful mission lasted for 17 years.

It was followed by RADARSAT 2, which was launched on 14 December 2007 aboard a Starsem Soyuz-FG rocket from the Baikonur Cosmodrome in Kazakhstan.

Launched into the same orbit as RADARSAT-1 but providing higher-resolution imaging and multiple polarisation modes, the spacecraft is still going almost 18 years later, which is quite a remarkable achievement.

The third iteration of the series is the RADARSAT Constellation Mission (RCM). Comprising three satellites launched in 2019 aboard a SpaceX Falcon 9 rocket, its multiple nature has brought new capabilities.

With 600-kilometre Sun-synchronous orbits, the three spacecraft provide daily coverage and improved monitoring that is used for purposes such as maritime surveillance, disaster response, increasing the safety of travel through regions of ice, and climate research.

And like many other spacecraft, the RCM triplets carry an Automatic Identification System payload for the shipping industry.

But that’s not where the story ends. In 2023, the Canadian government allocated CA$1.012 billion to the Canadian Space Agency to design and develop a replenishment satellite for the RCM, and to design a next-generation satellite system to succeed the overall mission.