COSMO-SkyMed (COnstellation of small Satellites for the Mediterranean basin Observation) is an Earth-observation satellite space-based radar system funded by the Italian Ministry of Research and Ministry of Defence and conducted by the Italian Space Agency (ASI), intended for both military and civilian use. The prime contractor for the spacecrafts was Alenia Spazio.
The space segment of the system includes four identical medium-sized (1900 kg ) satellites called COSMO-SkyMed (or COSMO) 1, 2, 3, 4, equipped with synthetic aperture radar (SAR) sensors with global coverage of the planet. Observations of an area of interest can be repeated several times a day in all-weather conditions. The imagery will be applied to defense and security assurance in Italy and other countries, seismic hazard analysis, environmental disaster monitoring, and agricultural mapping.
The four satellites are in sun-synchronous polar orbits with a 97.9° inclination at a nominal altitude of 619 km and an orbital period of 97.2 minutes. The local time ascending node at the equator is 06:00. The operating life of each satellite is estimated to be 5 years. Each satellite repeats the same ground track every 16 days. They cross the equator at approximately 06:00 and 18:00 local-time each day and can image any point twice each day. The satellites are phased in the same orbital plane, with COSMO-SkyMed's 1, 3, and 2 at 90° intervals followed by COSMO-SkyMed 4 at 67.5° after COSMO-SkyMed 2. The offset of satellite 4 allows a one-day interferometry mode for elevation information. The sun-synchronous orbit is used to keep the solar cells illuminated at all times.
The satellites' main components are:
The radar antenna is a phased array that is 1.4 m wide x 5.7 m long. The system is capable of both single- and dual-polarization collection. The center frequency is 9.6 GHz with a maximum radar bandwidth of 400 MHz.
United Launch Alliance provided launch services for the satellites with their Delta II 7420-10C rockets from Vandenberg Air Force Base. Satellite processing for the first two satellites was handled by the Astrotech Space Operations subsidiary of SPACEHAB. The first satellite COSMO-1 (COSPAR 2007-023A) was launched at 02:34 UTC on 8 June 2007. COSMO-2 (COSPAR 2007-059A) was launched at 02:31:42 UTC on 9 December 2007, the launch having been delayed from 6 December 2007 due to bad weather, and problems with the rocket's cork insulation. COSMO-3 (COSPAR 2008-054A) launched at 02:28 UTC on 25 October 2008. COSMO-4 (COSPAR 2010-060A) launched on 6 November 2010 02:20 UTC.
The ground segment of the system is composed of:
The Argentinian and the French governments are involved respectively in the civil and military segments of the system.
The COSMO-SkyMed satellites have three basic types of imaging modes:
There are two Spotlight modes:
There are two Stripmap modes:
There are two ScanSAR modes:
The system is sized to collect up to 450 images per satellite per day.
e-GEOS, S.p.A., a joint venture between European spaceflight services company Telespazio and the Italian Space Agency (ASI), has the exclusive worldwide commercial rights to sell COSMO-SkyMed data and products.
The COSMO-SkyMed satellites are lesser-known deliverers of satellite flares, sometimes approaching magnitude −3. Flares come mainly from SAR-panels of the satellites. Although overshadowed by the Iridium satellites, the flares are often long-lasting, with the satellites traversing much of the sky at brighter-than-average magnitudes.
To replace the first COSMO-SkyMed constellation, the Italian Space Agency is developing the COSMO-SkyMed 2nd generation constellation. The 2nd generation constellation has the same function of radar-based Earth observation with particular focus on the Mediterranean area as the 1st generation. The main difference from 1st generation is that the 2nd generation consists of only 2 satellites, CSG-1 and CSG-2. The satellites are improved versions of the first generation satellites. Also the radar payload CSG-SAR (COSMO-SkyMed Second Generation Synthetic Aperture Radar) is an improved version of the first generation X-band SAR payload. Furthermore, the 2nd generation satellites will operate in the same orbit (indeed, in the same orbital plane) as the first generation satellites. The 2nd generation satellites slightly outweigh the first generation satellites at 2230 kg mass.
The contract for building the satellites was signed in September 2015. The satellites are built by Thales Alenia Space (the successor company of Alenia Spazio). They have a planned lifetime of 7 years. CSG 1 was launched 18 December 2019 by Soyuz ST-A from Centre spatial Guyanais. As of October 2020, CSG 2 satellite targets launch for October 2020.