COSMO-SkyMed

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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.[1]

The space segment of the system includes four identical medium-sized satellites equipped with synthetic aperture radar (SAR) sensors with global coverage of the planet.[2] 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.[3]

Space segment[edit]

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 expected operating life of each satellite is estimated to be 5 years. Each satellite repeats the same ground track every 16 days, and all of the satellites follow the same ground track. They cross the equator at 06:00 and 18:00 local-time each day. The satellites are phased in the same orbital plane, with COSMO-SkyMed's 1, 2 and 4 at 90° to each other and COSMO-SkyMed 3 at 67.5° from COSMO-SkyMed 2. This results in varied intervals between the satellites along the same ground track of between 1 and 15 days. 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.[4]

Launch[edit]

United Launch Alliance is providing launch services for the first three satellites. Satellite processing for the first two satellites was handled by the Astrotech Space Operations subsidiary of SPACEHAB.[3] The first satellite was launched at 22:34 GMT, on 8 June 2007, aboard a Delta II 7420-10 rocket from Vandenberg AFB.[5] An identical rocket launched COSMO-2 at 02:31:42 GMT on 9 December 2007,[6] the launch having been delayed from 6 December due to bad weather, and problems with the rocket's cork insulation. COSMO-3 launched at 02:38 GMT on 25 October 2008, also aboard a Delta II 7420-10. A Delta II flying in the 7420-10 configuration will also be used to launch COSMO-4.[7] Launched from Vandenberg Air Force Base on November 5, 2010 at 1920L.

Ground segment[edit]

The ground segment of the system is composed of:

  • Command Center:
    •  Italian Centro Controllo e Pianificazione Missione del Fucino
  • Tracking and data stations:
  • User Ground Segments:
    •  Italian Matera Civil User Ground Segment
    •  Italian Pratica di Mare Defence User Ground Segment
    •  France Defence User Ground Segment

The Argentinian and the French governments 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 over a 10 km x 10 km 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 over a swath of 40 km, and
  • PINGPONG, which collects dual-polarization data at 15 m resolution over a swath of 30 km. 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 resolution data over a swath of 100 km, and
  • HUGEREGION, which provides 100 m resolution data over a swath of 200 km.

The system is sized to collect up to 450 images per satellite per day.[8]

Commercialization[edit]

eGEOS, S.p.A. has the exclusive worldwide commercial rights to sell COSMO-SkyMed data and products.[9]

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.

See also[edit]

References[edit]

  1. ^ "COSMO-SkyMed: Mission definition and main applications and products" (PDF). ESA.
  2. ^ "COSMO-SkyMed". Telespazio. Archived from the original on 2007-07-08.
  3. ^ a b "SPACEHAB Subsidiary Signs New Contracts Totaling $4.7 Million". SPACEHAB.
  4. ^ "COSMO-SkyMed User Guide" (PDF). ASI.
  5. ^ "Worldwide launch schedule". Spaceflight Now. Archived from the original on 2013-09-11.
  6. ^ NASA Spaceflight.com – Delta II launches with COSMO-SkyMed-2 Archived December 8, 2007, at the Wayback Machine.
  7. ^ "Boeing To Launch Fourth EO Satellite For Italy". SpaceDaily. Dec 23, 2008.
  8. ^ "eGEOS COSMO-SkyMed Overview". eGEOS.
  9. ^ "eGEOS: COSMO-SkyMed Overview". eGEOS.

External links[edit]