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COSMO-SkyMed
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A COSMO-SkyMed flare above the UK | |
| Manufacturer | Thales Alenia Space |
|---|---|
| Country of origin | Italy |
| Operator | ASI |
| Applications | Earth observation radar |
| Website | http://www.cosmo-skymed.it/it/index.htm |
| Specifications | |
| Bus | PRIMA |
| Launch mass | 1,700 kg (3,700 lb)[1] |
| Power | 4 kW |
| Regime | Sun-synchronous orbit |
| Design life | 5 years (planned) |
| Production | |
| Status | Operational |
| On order | 4 |
| Built | 4 |
| Launched | 4 |
| Operational | 4 |
| Maiden launch | COSMO-1 23 June 2007, 02:34:00 UTC |
| Last launch | COSMO-4 5 November 2010, 02:20:03 UTC |
| Manufacturer | Thales Alenia Space |
|---|---|
| Country of origin | Italy |
| Operator | ASI |
| Applications | Earth observation radar |
| Website | http://www.cosmo-skymed.it/it/index.htm |
| Specifications | |
| Bus | PRIMA |
| Launch mass | 2,205 kg (4,861 lb)[2] |
| Power | 5 kW |
| Regime | Sun-synchronous orbit |
| Design life | 7 years (planned) |
| Production | |
| Status | Operational |
| On order | 4 |
| Built | 2 |
| Launched | 2 |
| Operational | 1 |
| Maiden launch | CSG-1 18 December 2019, 08:54 UTC |
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.[3] The prime contractor for the spacecraft was Thales Alenia Space. COSMO SkyMed is a constellation of four dual use Intelligence, surveillance, target acquisition, and reconnaissance (ISR) Earth observation satellites with a synthetic-aperture radar (SAR) as main payload, the result of the intuition of Giorgio Perrotta in the early nineties. The synthetic-aperture radar was developed starting in the late nineties with the SAR 2000 program funded by ASI.
The space segment of the system includes four identical medium-sized 1,700 kg (3,700 lb) satellites called COSMO-SkyMed (or COSMO) 1, 2, 3, 4, equipped with synthetic-aperture radar (SAR) sensors with global coverage of the planet.[4] Observations of an area of interest can be repeated several times a day in all-weather conditions. The imagery is applied to defense and security assurance in Italy and other countries, seismic hazard analysis, environmental disaster monitoring, and agricultural mapping.[5]
COSMO-SkyMed first generation
[edit]The four satellites are in Sun-synchronous polar orbits with a 97.90° inclination at a nominal altitude of 619 km (385 mi) and an orbital period of 97.20 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.[6] The Sun-synchronous orbit (SSO) is used due to power (Electrical Power Subsystem) and revisit time requirements.
The satellites' main components are:
- Two solar arrays for 3.8 kW at 42 V DC
- Stabilization, navigation and Global Positioning System (GPS) systems
- Synthetic-aperture radar (SAR) working in X-band
- 300 Gbit on-board memory and 310 Mbit/s data-link with ground segments
The radar antenna is a phased array that is 1.4 × 5.7 m (4 ft 7 in × 18 ft 8 in). 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.[7]
List of launches
[edit]United Launch Alliance provided launch services for the satellites with their Delta II 7420-10C launch vehicles from Vandenberg Air Force Base.[8] Satellite processing for the first two satellites was handled by the Astrotech Space Operations subsidiary of SPACEHAB.[5] The first satellite COSMO-1 (COSPAR 2007-023A) was launched at 02:34:00 UTC on 8 June 2007.[9] COSMO-2 (COSPAR 2007-059A) was launched at 02:31:42 UTC on 9 December 2007,[10] 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, at 02:20 UTC.[11]
| Flight No. | Date/Time (UTC) | Launch site | Launch vehicle | Payload | Outcome |
|---|---|---|---|---|---|
| 1 | 8 June 2007, 02:34:00 | VAFB, SLC-2W | Delta II 7420-10 | COSMO-1 | Success |
| 2 | 9 December 2007, 02:31:42 | VAFB, SLC-2W | Delta II 7420-10 | COSMO-2 | Success |
| 3 | 25 October 2008, 02:28:25 | VAFB, SLC-2W | Delta II 7420-10C | COSMO-3 | Success |
| 4 | 6 November 2010, 02:20:03 | VAFB, SLC-2W | Delta II 7420-10C | COSMO-4 | Success |
Ground segment
[edit]The ground segment of the system is composed of:
- Command Center:
- Tracking and data stations:
Argentine Cordoba Station
Sweden Kiruna Station
- User Ground Segments:
The governments of Argentina and France are involved respectively in the civil and military segments of the system.
SAR capabilities
[edit]The COSMO-SkyMed satellites have three basic types of imaging modes:
- Spotlight, a high-resolution mode collected over a small area by steering the radar beam slightly fore-to-aft during the collection period
- Stripmap, a medium-resolution mode collected over long, continuous swaths in which the beam is pointed broadside to the satellite track
- ScanSAR, a low-resolution mode that creates extra-wide swaths by collecting short segments at different ranges and then mosaicking them together
There are two Spotlight modes:
- SPOTLIGHT1, which is a military-only mode, and
- SPOTLIGHT2, which provides a resolution of 1 m (3 ft 3 in) over a 10 × 10 km (6.2 × 6.2 mi) area. Spotlight polarization is limited to either HH or VV
There are two Stripmap modes:
- HIMAGE, which provides a resolution of between 3 and 5 m (9.8 and 16.4 ft) over a swath of 40 km (25 mi), and
- PINGPONG, which collects dual-polarization data at 15 m (49 ft) resolution over a swath of 30 km (19 mi). The dual-polarization data can consist of any two polarizations (HH, VV, VH, HV), and it is non-coherent, as it is collected in "pulse groups" that alternate from one polarization to the other.
There are two ScanSAR modes:
- WIDEREGION, which provides 30 m (98 ft) resolution data over a swath of 100 km (62 mi), and
- HUGEREGION, which provides 100 m (330 ft) resolution data over a swath of 200 km (120 mi).
The system is sized to collect up to 450 images per satellite per day.[12]
-
Overview of Damage Proxy Map from COSMO-SkyMed data
-
View of Norcia before October 2016 Central Italy earthquakes
-
View of Norcia after October 2016 Central Italy earthquakes
Commercialization
[edit]e-GEOS, S.p.A., a joint venture between European spaceflight services company Telespazio (80%) and the Italian Space Agency (ASI) (20%), has the exclusive worldwide commercial rights to sell COSMO-SkyMed data and products.[13][12]
Flares
[edit]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.
COSMO-SkyMed second generation (CSG)
[edit]To replace the first COSMO-SkyMed constellation, the Italian Space Agency is developing the COSMO-SkyMed second 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. Like the 1st generation, the 2nd generation also consists of 4 satellites, CSG-1, CSG-2, CSG-3 and CSG-4. 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 2,205 kg (4,861 lb) of mass.[14]
The contract for building two satellites was signed in September 2015. In December 2020, another two satellites were ordered. 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 on 18 December 2019 by Soyuz ST-A from Centre spatial Guyanais (CSG). CSG-2 was launched on 31 January 2022 by Falcon 9 Block 5 from Space Launch Complex 40 at Cape Canaveral Space Force Station,[15] while the CSG-3 satellite is scheduled to be launched in 2024 on a Vega-C launch vehicle.[16]
List of launches
[edit]| Flight No. | Date/Time (UTC) | Launch site | Launch vehicle | Payload | Outcome | Notes |
|---|---|---|---|---|---|---|
| 1 | 18 December 2019, 08:54:20 | Kourou, ELS | Soyuz ST-A / Fregat-MT | CSG-1 | Success | On 18 January 2021, COSMO-SkyMed Second Generation-1 (CSG-1) became operational with the first of four satellites.[17] |
| 2 | 31 January 2022, 23:11:14 | CCSFS, SLC-40 | Falcon 9 Block 5 ♺ B1052.3[18] |
CSG-2 | Success | On 31 January 2022, SpaceX launched COSMO-SkyMed Second Generation FM2 mission to low Earth orbit from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida. |
| 3 | 2025 | Kourou, ELV | Vega-C | CSG-3 | Planned | |
| 4 | 2027 ? | Kourou, ELV | Vega-C | CSG-4 | Planned |
See also
[edit]References
[edit]- ^ "COSMO-SkyMed (Constellation of 4 SAR Satellites)". eoportal.org. Retrieved 26 November 2020.
- ^ "COSMO-SkyMed Second Generation (CSG) Constellation". eoportal.org. Retrieved 26 November 2020.
- ^ "COSMO-SkyMed: Mission definition and main applications and products" (PDF). ESA.
- ^ "COSMO-SkyMed". Telespazio. Archived from the original on 8 July 2007.
- ^ a b "SPACEHAB Subsidiary Signs New Contracts Totaling US$4.7 million". SPACEHAB.
- ^ "COSMO-SkyMed Mission and Products Description 23/01/2019". e-geos.my.salesforce.com. Italian Space Agency. Retrieved 24 August 2020.
- ^ "COSMO-SkyMed User Guide" (PDF). ASI. Archived from the original (PDF) on 29 August 2017. Retrieved 8 November 2012.
- ^ "Boeing To Launch Fourth EO Satellite For Italy". SpaceDaily. 23 December 2008.
- ^ "Worldwide launch schedule". Spaceflight Now. Archived from the original on 11 September 2013.
- ^ NASA Spaceflight.com – Delta II launches with COSMO-SkyMed-2 Archived 8 December 2007 at the Wayback Machine
- ^ "COSMO 1, 2, 3, 4". Gunter's Space Page. 7 July 2020. Retrieved 12 October 2021.
- ^ a b "eGEOS: COSMO-SkyMed Overview". eGEOS. Archived from the original on 22 July 2013. Retrieved 10 August 2011.(subscription required)
- ^ "E-GEOS to Create Early Warning System for Caribbean Weather Emergencies". satellitetoday.com. 18 December 2018. Retrieved 23 August 2019.
- ^ "CSG 1, 2, 3, 4 (COSMO-SkyMed 2nd Gen.)". Gunter's Space Page. 3 October 2021. Retrieved 12 October 2021.
- ^ "Falcon 9 finally launches with Italian CSG-2 Earth observation satellite". NASASpaceflight. 31 January 2022. Retrieved 1 February 2022.
- ^ "COSMO-SKYMED". Italian Space Agencydate. 3 October 2021. Retrieved 3 October 2021.
- ^ "COSMO-SkyMed". Agenzia Spaziale Italiana. 12 October 2021. Retrieved 12 October 2021.
- ^ "CSG-2 | Falcon 9 Block 5". 25 January 2022.
External links
[edit]- COSMO-SkyMed Web Site
- COSMO-SkyMed Products Archived 22 July 2013 at the Wayback Machine
- INNOVA Consorzio per l'Informatica e la Telematica s.r.l. Archived 2 February 2009 at the Wayback Machine – Italian SME with specific know-how and expertise with COSMO-SkyMed's HDF5 format
- Remote Monitoring of Migrants Vessels in the Mediterranean Sea (CeMiSS)
COSMO-SkyMed
View on GrokipediaFunded primarily by the Italian Space Agency (ASI) in collaboration with the Ministry of Defence and Ministry of Education, University and Research, the first-generation constellation consists of four satellites launched between 2007 and 2010 into sun-synchronous polar orbits at approximately 620 km altitude, enabling revisit times as short as a few hours for targeted areas and supporting global coverage.[1][2][3]
The system's SAR instrumentation operates in multiple modes, including spotlight for resolutions down to 1 meter, stripmap for broader coverage at 3-5 meters, and scansar for wide-area monitoring up to 200 km swaths, facilitating applications in disaster response, environmental surveillance, maritime security, and military reconnaissance.[2][4]
Notable achievements include rapid imagery provision for emergency management, such as damage assessment following the 2016 central Italy earthquakes via change-detection processing of pre- and post-event data, and continuous territorial monitoring that has supported resource management and security operations since operational inception.[2][5]
A second-generation constellation, featuring improved resolution, larger antennas, and enhanced data processing, began launching in 2019 to sustain and upgrade capabilities through at least 2030, marking Italy's most ambitious Earth observation endeavor.[6][7]
Development and Program Overview
Origins and Strategic Rationale
The COSMO-SkyMed program originated from initiatives by the Italian Space Agency (ASI) in the mid-1990s to develop advanced synthetic aperture radar (SAR) technology for Earth observation, building on the SAR 2000 research effort funded by ASI starting in the late 1990s.[2] Conceived in 1996 as a constellation of small satellites focused on the Mediterranean basin, it received initial government funding and was incorporated into Italy's 1998-2002 National Space Plan by 1997.[2] This early phase emphasized establishing sovereign capabilities in space-based radar imaging, independent of foreign systems, to address regional monitoring needs. In 2001, the Italian Ministry of Defence (MoD) joined as a key partner, shifting the program toward explicit dual-use architecture with military applications in mind, while ASI retained primary civil oversight.[2] Funding was allocated with the Ministry of Research providing 75% and the MoD 25%, reflecting a cost-sharing model to support both national security imperatives and broader scientific objectives.[2] The program's development prioritized X-band SAR instruments capable of high-resolution imaging under all weather conditions and at any time, enabling persistent surveillance over strategically vital areas. The strategic rationale lay in bolstering Italy's defense posture through enhanced intelligence, surveillance, and reconnaissance (ISR) for territorial protection and crisis response in the Mediterranean, a region of geopolitical interest due to migration, maritime security, and potential conflicts.[2] Simultaneously, civil benefits justified the investment, including disaster risk reduction, environmental monitoring, and resource management, with the dual-use design allowing data sharing between military and civilian users to optimize operational efficiency and national resilience.[1][2] This approach positioned COSMO-SkyMed as Italy's largest Earth observation endeavor, fostering technological independence and international collaboration while mitigating reliance on external satellite assets.[2]Funding and International Collaboration
The COSMO-SkyMed program is financed primarily by Italian governmental entities, including the Agenzia Spaziale Italiana (ASI), the Ministry of Defence, and the Ministry of Education, Universities and Research (MIUR).[8][5] The first-generation constellation development, approved in the early 2000s, had an estimated total cost of approximately €900 million, covering satellite construction, launches, and ground infrastructure.[9] Subsequent phases, including the second-generation system, have involved additional allocations, such as €66.6 million in 2014 for design work and €182 million in 2015 for further development.[9][10] International collaboration emphasizes data sharing and joint operations rather than direct funding contributions, enabling enhanced global coverage for dual-use applications. A key partnership is the SIASGE (Sistema Italo-Argentino de Satélites para la Gestión de Emergencias) initiative with Argentina's Comisión Nacional de Actividades Espaciales (CONAE), integrating COSMO-SkyMed's X-band synthetic aperture radar capabilities with Argentina's SAOCOM L-band constellation to improve disaster management and risk assessment through complementary imaging.[11][12] France maintains access to the program's military segments under bilateral agreements, supporting intelligence and surveillance interoperability.[13] Additional frameworks exist with Poland for second-generation ground segment integration and data access, and with Finland for cooperative use of the system.[14][15] The European Space Agency (ESA) facilitates broader international data distribution via its Third Party Missions program, without financial involvement in the core development.[16]Program Objectives and Dual-Use Design
The COSMO-SkyMed program seeks to establish a sovereign, high-resolution synthetic aperture radar (SAR) constellation for continuous Earth observation, enabling all-weather, day-and-night imaging with global coverage and revisits multiple times per day.[16] Its core objectives encompass strategic surveillance of Italian territory and maritime zones, environmental monitoring for risks including floods, landslides, and deforestation, and applications in civil protection, resource management, and urban planning.[4][17] The system supports rapid data delivery to address user needs in land surface monitoring, maritime surveillance, and disaster response, leveraging X-band SAR for resolutions down to 1 meter in spotlight mode.[18] As a dual-use initiative, COSMO-SkyMed integrates civilian and military functionalities from its foundational design, jointly funded by the Italian Ministry of Defense, Ministry of Education, University and Research, and Italian Space Agency (ASI), with the defense sector providing primary operational control.[1][2] This architecture permits prioritized access for military intelligence, surveillance, and reconnaissance (ISR) tasks—such as border control and threat assessment—while allocating capacity for civilian institutions in areas like emergency mapping and agricultural oversight.[19] Data policies enforce sharing mechanisms between user classes, ensuring defense requirements do not preclude civil exploitation, thereby enhancing national security alongside sustainable development goals.[20] The program's end-to-end system, including ground segments, facilitates this interoperability without compromising classified military data handling.[21]First Generation Constellation
Satellite Architecture and Initial Capabilities
The first-generation COSMO-SkyMed satellites are medium-sized platforms, each with a launch mass of approximately 1,900 kg and a dry mass of 1,690 kg, constructed by Alenia Spazio (now Thales Alenia Space) using a modular bus architecture optimized for low-Earth orbit operations.[4] The bus includes subsystems for power generation via deployable solar arrays providing up to 4 kW, attitude control with momentum wheels and thrusters for precise pointing, and onboard data storage and processing capable of handling high-volume SAR data.[2] The primary payload is the SAR-2000 instrument, a synthetic aperture radar operating in X-band at 9.6 GHz with a 3.1 cm wavelength, featuring a 12 m deployable antenna and right-looking geometry for single-polarization (HH or VV) imaging.[2][22] The SAR payload supports four main imaging modes to balance resolution, swath width, and coverage: Spotlight (high-resolution narrow swath), HIMAGE (stripmap high-resolution), and two ScanSAR modes for wide-area surveillance. In Spotlight mode, spatial resolutions better than 1 m are achieved over 10 km × 10 km scenes, suitable for detailed target identification. HIMAGE mode delivers 3 m resolution over 30 km swaths, while ScanSAR modes provide 10 m to 100 m resolutions across 100 km to 200 km swaths, enabling rapid mapping of large areas.[2][21] These modes operate in all weather and lighting conditions, with incidence angles from 25° to 50°, supporting data rates up to 140 Mbps and raw data products processed into levels from single-look complex to geocoded terrain-corrected imagery.[23] Initial capabilities, demonstrated by the first satellite launched on June 8, 2007, included worldwide accessibility for data acquisition from a single platform, with equatorial revisit times of about 16 days improving to under 12 hours upon full constellation deployment. The system emphasized dual-use functionality, prioritizing secure military modes like Spotlight-1 (restricted access) alongside civilian applications such as environmental monitoring, though early operations focused on validation of SAR performance and integration with the Italian ground segment for rapid tasking and delivery.[21][24] Limitations in the initial design included single-polarization only and no interferometric capabilities in the baseline setup, which were later augmented through constellation synergies for change detection and basic interferometry.[22]Launch Timeline and Operational Deployment
The first-generation COSMO-SkyMed constellation was deployed progressively through launches of four identical satellites between 2007 and 2010, enabling initial civil and dual-use Earth observation capabilities shortly after the second satellite's commissioning, with full constellation performance attained by mid-2011.[2][1]| Satellite | Launch Date | Launch Vehicle | Launch Site |
|---|---|---|---|
| COSMO-SkyMed 1 | June 8, 2007 | Delta II | Vandenberg AFB, California, USA |
| COSMO-SkyMed 2 | December 9, 2007 | Delta II | Vandenberg AFB, California, USA |
| COSMO-SkyMed 3 | October 25, 2008 | Delta II | Vandenberg AFB, California, USA |
| COSMO-SkyMed 4 | November 6, 2010 | Delta II | Vandenberg AFB, California, USA |
Early Performance Achievements
Following the launches of the first two satellites on June 8, 2007, and December 9, 2007, respectively, the COSMO-SkyMed constellation entered its commissioning phase, which verified the end-to-end system's performance, including SAR instrument calibration, product generation, and operational stability.[2] By August 1, 2008, both satellites were fully operational, demonstrating high nominal performances in image quality, radiometric accuracy, and geometric fidelity, with data takes confirming the delivery of calibrated Level 1 products across multiple imaging modes.[25] [26] The third satellite, launched on October 25, 2008, acquired its first images on November 25, 2008, during commissioning, and completed system qualification by July 2009, enabling the constellation to achieve up to 6 images per day over targeted areas.[2] This capability was promptly demonstrated in response to the L'Aquila earthquake on April 6, 2009, where the satellites provided rapid SAR imagery for damage assessment and emergency management, marking one of the earliest real-world applications of the system.[2] Additionally, initial monitoring efforts included ice coverage in the Northern Caspian Sea and Antarctic regions as early as February 2008, showcasing the constellation's all-weather, day-night imaging strengths.[2] Image quality assessments during these phases confirmed achievement of design specifications, including ≤1 m resolution in Spotlight mode over 10 km × 10 km scenes, 3 m resolution in Stripmap mode with 40 km swaths, and effective radiometry with low noise levels, supporting interferometric applications for surface deformation mapping.[26] [2] The fourth satellite's launch on November 6, 2010, and subsequent first images on December 16, 2010, finalized the constellation's deployment, with commissioning results affirming overall system reliability and paving the way for routine global coverage with revisit times under 12 hours.[2] These early milestones validated the dual-use design's efficacy for both civilian monitoring and defense surveillance.[27]Second Generation Constellation
Design Enhancements and Technological Advances
The second-generation COSMO-SkyMed (CSG) satellites feature a redesigned X-band Synthetic Aperture Radar (SAR) instrument, representing a significant evolution from the first-generation system by incorporating advanced electronics and antenna architectures for enhanced image quality, versatility, and agility.[28][29] This redesign enables finer spatial resolution in narrow-field modes, with Spotlight-2A achieving 0.3 m in range by 0.5 m in azimuth, surpassing the first generation's typical 1 m resolution in similar spotlight configurations.[8] Stripmap mode offers 3 m × 3 m resolution, while ScanSAR-2 supports wider coverage up to 200 km × 200 km scenes at 40 m × 6 m resolution, optimizing for both high-detail and broad-area monitoring.[8] A key technological advance is the introduction of full polarimetric (Quad Pol) capability, allowing simultaneous acquisition of HH, VH, HV, and VV polarizations, which was not available in the first generation's primarily single- or dual-polarization setup.[8][30] This enables more precise material characterization and interferometric applications, such as terrain deformation monitoring, by providing richer scattering information for advanced data processing.[8] The SAR also supports enhanced modes like PingPong for dual-polarization flexibility and new non-standard acquisitions, including multi-swath optimized resolution in DI2S Spotlight-1.[8] Innovative operational features include the world's first SAR capability for simultaneous high-resolution, dual-polarized imaging of geographically separated targets hundreds of kilometers apart during a single orbital pass, demonstrated in acquisitions such as Rome and Altamura on April 25, 2020.[29] This multi-beam functionality, enabled by the instrument's agility and beam steering, resolves traditional conflicts in imaging requests and expands versatility for time-critical tasks like disaster response.[29] The satellite platform builds on an improved PRIMA bus with increased mass (approximately 2,205 kg for CSG-1) and deployable solar arrays for sustained power, ensuring a 7-year design life while maintaining compatibility with the first-generation orbital configuration.[31] These advances collectively provide a generational leap in resolution, polarization diversity, and multi-target efficiency, supporting dual civil-military objectives with greater precision.[32][28]Launch Progress and Deployment Status
The COSMO-SkyMed Second Generation (CSG) constellation is planned to consist of four satellites to ensure continuity and enhanced performance beyond the first generation system. As of October 2025, two satellites have been successfully launched and deployed into operational sun-synchronous orbits at approximately 620 km altitude. The remaining two await launch, with deployment expected to achieve full constellation coverage for dual civil and military Earth observation missions.[28][31] CSG-1, the first satellite, was launched on December 18, 2019, at 08:54 UTC from the Guiana Space Centre in Kourou, French Guiana, aboard a Vega rocket with an Fregat upper stage. Following separation, ground controllers at the Telespazio Fucino Space Centre in Italy acquired signal and initiated early orbit phase maneuvers, leading to full operational status after commissioning. The satellite operates nominally, delivering high-resolution X-band SAR imagery with improved swath width and resolution compared to predecessors.[8][33] CSG-2 launched on January 31, 2022, at 23:11 UTC from Space Launch Complex 40 at Cape Canaveral Space Force Station, Florida, using a SpaceX Falcon 9 Block 5 rocket. The mission marked the first commercial launch for an Italian institutional satellite under this program. Post-launch, the satellite separated successfully, and Italian ground stations assumed control within hours, completing in-orbit testing and integration into the constellation by mid-2022. Both CSG-1 and CSG-2 contribute to routine operations, enabling frequent revisits over priority areas despite the incomplete constellation.[28][31] CSG-3 and CSG-4 remain in pre-launch preparation, with CSG-3 scheduled for liftoff no earlier than December 2025 on a Vega-C rocket from Kourou, and CSG-4 targeted for November 2025 or later on a similar launcher. Delays in Vega-C qualification and integration have pushed timelines, but both satellites have completed assembly and testing by prime contractor Leonardo. Full deployment of the four-satellite array will support global coverage with revisit times under 12 hours in spotlight modes, enhancing strategic monitoring and disaster response capabilities.[34][35][36]Performance Improvements Over First Generation
The COSMO-SkyMed Second Generation (CSG) satellites incorporate an advanced X-band synthetic aperture radar (SAR) payload with a 300% increase in operative bandwidth compared to the first generation (CSK), enabling finer spatial resolutions and enhanced radiometric performance.[28] Spotlight modes achieve resolutions as fine as 0.3 m in azimuth by 0.5–0.6 m in range for Spotlight-2A, surpassing the CSK's sub-meter Spotlight capabilities, while Stripmap maintains 3 m resolution with improved swath efficiency.[8] ScanSAR modes offer 4 m × 20 m (ScanSAR-1) and 6 m × 20 m (ScanSAR-2) resolutions over wider swaths up to 200 km, supporting up to six subswaths for broader coverage without sacrificing detail.[28]| Mode | CSG Resolution (Azimuth × Range) | CSK Equivalent Resolution |
|---|---|---|
| Spotlight-2A | 0.3 m × 0.5–0.6 m | <1 m (general Spotlight) |
| Spotlight-2B | 0.6 m × 0.6 m | <1 m (general Spotlight) |
| Stripmap | 3 m × 3 m | 3 m |
| ScanSAR-1 | 4 m × 20 m | 8–10 m × 20 m |
| ScanSAR-2 | 6 m × 20 m | 20–40 m × 20 m |
Orbital and Mission Parameters
Constellation Configuration and Coverage
The COSMO-SkyMed constellation operates primarily in a sun-synchronous dawn-dusk orbit at an altitude of 619.6 km, with an inclination of 97.86° and an orbital period of 97.1 minutes.[2][28] The first-generation component consists of four satellites deployed between 2007 and 2010, arranged in a nominal configuration with the satellites equally spaced along the same orbital plane to optimize revisit frequency and coverage overlap.[2] This setup enables a repeat cycle of 16 days per satellite, but the full quartet reduces effective global revisit times to a few hours for priority areas, with a single satellite capable of near-revisits every five days.[16] For specialized interferometric observations, the constellation can shift to a tandem configuration, positioning two satellites in close proximity within the same plane or in a tandem-like arrangement across slightly offset planes to facilitate phase-coherent data collection for applications like topographic mapping and deformation monitoring.[2] The second-generation satellites, designed as enhanced replacements and supplements, follow the identical orbital parameters and plane, ensuring seamless integration with the first-generation assets.[28] As of October 2025, two second-generation satellites have been launched (in December 2019 and January 2022), with the remaining two scheduled for deployment in 2025 and 2026, aiming for a combined fleet that sustains operational continuity amid first-generation attrition, such as the deorbiting of one early satellite.[31][28] The overall configuration yields global coverage across latitudes accessible to the near-polar orbit, with a cross-track field of regard up to 1300 km, supporting all-weather, day-night imaging via X-band SAR regardless of first-generation satellite count.[2] In full nominal operation, the constellation achieves high temporal resolution, enabling up to 1800 daily image acquisitions per satellite in modes like Stripmap or ScanSAR, prioritized for the Mediterranean basin but extensible worldwide for dual civil-military needs.[2] The phased satellite distribution minimizes gaps, providing sub-daily revisits over equatorial and mid-latitude regions, though polar areas benefit less frequently due to orbital geometry.[2] This architecture balances spatial coverage with interferometric flexibility, though actual revisit performance varies by mode, incidence angle (typically 20°-59°), and tasking demands.[2]Revisit Times and Operational Modes
The COSMO-SkyMed first-generation satellites orbit in a sun-synchronous dawn-dusk configuration at 619.6 km altitude, with a 97.86° inclination, 97.1-minute period, and 16-day repeat cycle.[2][16] A single satellite yields a near-revisit time of approximately five days for any given location.[16][2] The full four-satellite constellation, with satellites phased at 90° intervals in a single orbital plane, reduces global revisit times to a few hours under nominal operations, though worst-case scenarios may extend to under 12 hours depending on incidence angle and viewing direction.[16][2] The SAR instrument operates in multiple modes to balance resolution, swath width, and polarization options (typically single VV or dual-pol in PingPong). Spotlight mode provides sub-meter resolution (≤1 m) over targeted 10 km × 10 km scenes, prioritizing fine detail for applications like infrastructure monitoring.[2][16] Stripmap HIMAGE mode achieves 3 m resolution across 40 km swaths for continuous high-fidelity strips, while PingPong Stripmap supports 15 m resolution with dual polarization (HH/VV, HV, or VH) over 30 km swaths to enhance surface discrimination.[2][16] For extensive area surveillance, ScanSAR WideRegion mode delivers 30 m resolution over 100 km swaths, and HugeRegion mode offers 100 m resolution across 200 km swaths, facilitating rapid wide-area mapping despite coarser detail.[2][16] Mode selection depends on mission priorities, with right- or left-looking capabilities and incidence angles of 20°–45° enabling flexible tasking.[2] The second-generation constellation employs comparable orbital parameters (619 km altitude, similar sun-synchronous setup) but enhances revisit performance through refined phasing and dual-polarization support across modes, with routine maximum revisits as low as 37 hours in partial deployment and interferometric options tied to the 16-day cycle for change detection.[2][38] Full second-generation deployment (four satellites by late 2020s) is projected to further shorten average revisits to 3–6 hours globally, augmenting first-generation capacities for hybrid operations.[2]SAR Technology and Imaging Features
X-Band Radar Specifications
The COSMO-SkyMed constellation employs the SAR-2000 synthetic aperture radar instrument, operating in the X-band at a center frequency of 9.6 GHz with a corresponding wavelength of 3.1 cm.[2] The radar supports a programmable instantaneous bandwidth, typically ranging from 30 MHz in scan modes to 140 MHz in spotlight and high-resolution stripmap configurations, enabling flexible range resolution adjustments.[21] Pulse repetition frequencies (PRF) operate between 3 and 4 kHz, with chirp durations varying by mode from 30–40 µs in stripmap and scansar to 70–80 µs in spotlight.[21] The antenna is a fixed phased-array design with electronic steering capabilities in both range and azimuth, measuring 5.7 m in length by 1.4 m in width and comprising 40 tiles with 1,280 transmit/receive (T/R) modules for high peak power generation directly within the array.[2] This configuration provides an access swath up to 630 km and programmable incidence angles spanning 18° to 59.9°, with a nominal boresight of approximately 38°.[2][21] Polarization options include single transmit/receive configurations (HH, VV, HV, VH) and dual-pol alternating modes (e.g., HH/VV, HH/HV), with full polarimetry supported via ping-pong techniques that alternate polarizations pulse-to-pulse.[2] Data acquisition supports raw signal downlinks at rates up to 600 Mbit/s nominally, with encryption and compression applied prior to X-band transmission to ground stations.[2] Geolocation accuracy exceeds 15 m when incorporating digital elevation models, without requiring ground control points.[21]Resolution Modes and Data Products
The COSMO-SkyMed constellation's SAR instrument operates in multiple imaging modes optimized for varying trade-offs between spatial resolution and coverage area. These include Spotlight for high-resolution imaging of small targets, Stripmap for medium-resolution continuous strips, and ScanSAR for wide-area surveillance. The modes support single or dual polarizations (HH, VV, HV, VH) and incidence angles ranging from approximately 18° to 60°, enabling flexible acquisition geometries.[21][39]| Mode | Azimuth Resolution (m) | Ground Range Resolution (m) | Swath Width (km) | Typical Scene Size (km) | Notes |
|---|---|---|---|---|---|
| Spotlight-1 | ≤1 | ≤1 | N/A | 10 × 10 | Military-only mode with sub-meter capability.[2] |
| Spotlight-2 | ≤1 | ≤1 | N/A | 10 × 10 | Civil-accessible high-resolution mode.[2][39] |
| Stripmap HIMAGE | ≤3 (single-look); ≤5 (multi-look) | ≤3–5 (varies with incidence) | ≥40 | Variable strip | Balances resolution and swath for general mapping.[21][39] |
| Stripmap PingPong | ≤20 (multi-look) | ≤20 | 30 | Variable strip | Dual-pol mode for polarization diversity.[21] |
| ScanSAR Wide | ≤30 (multi-look) | ≤30 | 100 | 100 × 100 | Wide coverage for regional monitoring.[21][39] |
| ScanSAR Huge | ≤100 (multi-look) | ≤100 | 200 | 200 × 200 | Lowest resolution for broad-area scans.[21][39] |