Falcon 9 finally launches with Italian CSG-2 Earth observation satellite

by Justin Davenport

The Italian Space Agency’s CSG-2 mission, the second satellite in its COSMO-SkyMed Second Generation constellation, finally launched liftoff Monday at 6:11 PM EST (23:11 UTC) from Space Launch Complex 40 (SLC-40). The mission had suffered weather-related scrubs and even a cruise ship in the range, prior to lifting off on Monday.

The CSG-2, or COSMO-SkyMed Seconda Generazione 2, mission follows the first second-generation satellite, CSG-1, which was launched in December 2019 aboard a Soyuz rocket from Kourou, French Guiana. CSG-1 and 2 will operate in the same orbital plane as the four previous-generation COSMO-SkyMed (Constellation of Small Satellites for the Mediterranean Basin Observation) satellites which were launched between 2007 and 2010. The new satellites are designed to operate along with the first generation satellites for operational continuity.

Like their predecessors, the Second Generation satellites will be able to observe the same points on Earth twice a day, at 06:00 and 18:00 hours local time. The CSG-1 and CSG-2 satellites together will provide the same capability as the four spacecraft that made up the first-generation system.

The new satellites are designed to operate for at least seven years, improving on the first generation’s five-year design life, and can observe the globe in any weather or lighting conditions due to their use of X-band synthetic aperture radar (SAR) as opposed to optical systems which are negatively impacted by cloud cover.

Render of a CSG satellite in orbit — via Telespazio

Like the prior generation of COSMO-SkyMed satellites, CSG-1 and CSG-2 can provide imagery that is useful in monitoring natural disasters and observing their results, as well as other civil and military purposes including agriculture, maritime surveillance, reconnaissance, cartography, and risk management.

COSMO-SkyMed is under the overall control of the Italian Space Agency, Agenzia Spaziale Italiana (ASI). Italy’s Ministry of Defense is one of the program’s key stakeholders, with the constellation’s highest-resolution images restricted to military users.

The COSMO-SkyMed satellites have provided much useful data after natural disasters, including this month’s eruption of the Hunga Tonga volcano in the South Pacific. They have also assisted in the response to the 2008 Cyclone Nargis landfall in Myanmar, landslides after Typhoon Talas in Japan in 2011, the Nepal earthquake of 2015, the central Italy earthquakes of 2016, and many more events.

The CSG satellites were built by Thales Alenia Space, using the company’s Prima satellite bus which was also used on the first generation satellites. Although similar in appearance and dimensions, the second-generation satellites feature more advanced systems and capabilities and greater operational lifetime than the first generation satellites, taking advantage of technological advances since the first COSMO-SkyMed launch fifteen years ago.

CSG satellites feature radar systems that offer higher resolutions and greater image polarization capabilities than the first generation spacecraft. The system offers three operational modes, with the highest-resolution Spotlight mode split into Spotlight-1 for military users, with up to 0.8 meters resolution, and Spotlight-2, a lower-resolution mode for civilian usage.

The Stripmap mode offers resolutions of up to three meters, imaging strips measuring 15 kilometers in width and 2,500 km in length. This allows it to cover larger areas of land or water. The ScanSAR mode offers a resolution of four by 20 meters over an area of 100 by 3,000 kilometers, or six by 40 meters over an area of 200 by 2,500 kilometers.

Radar image of Genoa Airport from the CSG-1 satellite (Credit: ASI)

CSG-2’s radar imaging mission is supported by a new payload data handling and transmission (PDHT) system with double the storage capacity and throughput of that on the first generation satellites. This is supported by an augmented electrical and power generation system.

Alongside the upgrades to the satellites, their ground station operations have also been upgraded for the second-generation system, allowing more imagery to be provided to users with CSG than was possible with the first-generation constellation. Ground stations in Kiruna, Sweden and Cordoba, Argentina assist with communications, while the Fucino Space Center near Avezzano, Italy, is responsible for controlling the spacecraft.

COSMO-SkyMed forms part of several international partnerships, with France sharing access to the military functions of the constellation in return for providing Italy with access to images from its optical satellites. Argentina is involved in the civilian side of the program, coordinating observations from its own SAOCOM satellites, equipped with L-band radar imaging payloads, with the X-band imagery generated by COSMO-SkyMed.

The European Space Agency also has an agreement with the Italian Space Agency to distribute COSMO-SkyMed data products to scientific users, while the e-GEOS company, a joint venture between Telespazio and ASI, has exclusive worldwide rights to sell the constellation’s data and products commercially.

The CSG-1 and CSG-2 satellites were ordered in 2015, with a follow-on pair of satellites, CSG-3 and CSG-4, being ordered in 2020 to expand the COSMO-SkyMed constellation. CSG-3 is scheduled for launch in 2024 while CSG-4 is scheduled for launch in 2027, with both satellites expected to fly aboard Vega-C rockets from Kourou, French Guiana.

The CSG-2 satellite was launched by SpaceX, riding to orbit aboard a Falcon 9 rocket. The mission followed a southerly trajectory to insert the spacecraft to a 619.6-kilometer sun-synchronous orbit inclined 97.86 degrees to the equator, with a period of 97.1 minutes.

The launch used a flight-proven Falcon 9, with the booster – B1052-3 – having previously flown twice as a Falcon Heavy side booster, although this mission marks its first flight as part of a Falcon 9. It was previously part of the Falcon Heavy vehicles that launched Arabsat-6A in April 2019 and STP-2 in June of the same year.

B1052 is the first Falcon Heavy side booster to be converted and flown on Falcon 9. However, two Falcon 9 boosters have previously been converted the other way, serving as the side boosters on the Falcon Heavy’s 2018 test flight.

After lifting off from Space Launch Complex 40, Falcon 9 took a southward trajectory as it climbed through the atmosphere. The first stage’s nine Merlin-1D engines cut off around the T+2 minutes 30 seconds mark, with stage separation following shortly afterwards.

The second stage continued CSG-2’s journey to orbit while the first stage performed a boost back burn to put it on a course back to the launch site.

Unlike most recent Falcon 9 launches from Florida, the CSG-2 flight’s booster did not need a drone ship sent out to the Atlantic to recover it. Instead it flew a return to launch site (RTLS) profile, with the booster touching down on the concrete pad at Landing Zone 1 (LZ-1) back at the Cape.

The relatively low mass of the CSG-2 satellite, around 2,230 kilograms, enabled SpaceX to make a return to launch site landing on this mission, as it can deliver the satellite to its planned orbit with enough reserve performance for the first stage to perform the boostback maneuver. The RTLS landing presents less risk to the booster during the landing process and will greatly simplify the post-landing safing, recovery, and transport operations as the booster is returned to its hangar for future flight processing.

After the boostback burn was completed, B1052-3 positioned itself for atmospheric entry before conducting an entry burn to protect the stage from excess heating — fighting fire with fire — by slowing the stage down. The final landing burn began shortly before touchdown, slowing the booster to a soft landing at LZ-1.

While the first stage returns to Cape Canaveral, the second stage continued to fulfil the primary objective of the launch: deploying CSG-2 into orbit. The stage reached a parking orbit around nine minutes after launch, shutting down its Merlin Vacuum engine in an event designated Second Stage Engine Cutoff (SECO). The CSG-2 satellite was released into orbit shortly after SECO, and after commissioning, it will take its place in the COSMO-SkyMed constellation. 

This launch marked SpaceX’s fourth mission of 2022, coming nearly two weeks after the successful launch of a group of Starlink satellites aboard another Falcon 9 vehicle flying from the Kennedy Space Center’s Launch Complex 39A (LC-39A). The CSG-2 launch is the first of three Falcon launches scheduled in close succession, with another Starlink mission from LC-39A slated on Wednesday, coming just 93 minutes before a launch from Vandenberg Space Force Base deploys a payload for the National Reconnaissance Office.

Lead Image: Julia Bergeron for NSF.

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