On January 31 at 23:11 UTC, after four previous attempts, a SpaceX Falcon 9 finally launched the CSG-2 mission from SLC-40 at the Cape Canaveral Space Force Station in Florida. After liftoff, the Falcon 9 headed down the Florida coast to insert the satellite into a 97.5-degree inclination sun-synchronous orbit. The twilight launch and polar trajectory led to an amazing view on the ground tracking cameras at the end of the first stage burn.

The first three attempts were scrubbed because of bad weather, while the fourth was scrubbed because a cruise ship entered the restricted area offshore. The usual restricted areas for both planes and boats were different for this launch because of the polar trajectory, but the changed map was posted several days in advance.

Because the payload was so light, only about two metric tons, the Falcon 9 first stage performed a Return To Launch Site type landing, landing at Landing Zone 1 about nine minutes after launch. This is a rare type of landing since they usually land the boosters on their barges, but this is the second Return To Launch Site landing this month.

The second stage coasted for about an hour before performing a second burn and then deploying the satellite into orbit.

Booster 1052 is unique as Falcon 9 boosters go, even though this is only its third flight. Its first two launches were in 2019 as the starboard side-booster on the Arabsat 6A and STP-2 Falcon Heavy launches. The Falcon 9 first stages have been designed to be interchangeable between Falcon 9 first stage and Falcon Heavy side-boosters by switching just a few components around since the Block 5 version was introduced. However, until now, no booster had been through this process.

CSG-2 or COSMO-SkyMed Second Generation Flight 2 is the second satellite of a planned constellation for the Italian government. CSG-2 is a synthetic aperture radar satellite, a type of active imaging radar used for acquiring images at all times of day, including “all but the heaviest rainfall”. 

Radar satellites work kind of like sonar, sending out their own energy and recording the reflection. Many reflections are combined to build an image. Optical satellites, on the other hand, record light from the Sun reflected off the Earth. This quality makes them very useful for military applications, but radar satellites can also be used for agriculture and disaster monitoring such as floods, oil spills, and wildfires. Like the first generation, CSG-2 has dual military and civilian use.

CSG-2 has a number of different modes, each of which offers different resolutions and image sizes. Military users have access to a very high-resolution mode that provides imagery with pixels smaller than 80 by 80 centimeters, the highest resolution for civilian users. The coarsest resolution available has pixels that are 6 by 20 meters in size. Depending on the size of pixels, the ground coverage of an image can vary from a few kilometers on a side to large areas roughly 200 by 2,500 kilometers.

The CSG constellation will be finished by two launches of the Arianespace Vega-C rocket in the next few years.

More Information

CSG-2 mission page (SpaceX via archive.today)

Booster 1053 info (Reddit)

COSMO-SkyMed Second Generation (CSG) Constellation (eoPortal)

Applications of Synthetic Aperture Radar Satellites to Environmental Monitoring (CSIS)