SSTL Midisatellite Credit - NASA

Enlarged version of the basic Surrey Microsat bus.

The MicroSat-100 enhanced microsatellite platform expanded the range of SSTL's modular microsatellite to missions of 70 to 130 kg total mass, with a typical payload mass of up to 40 kg.

Whilst building extensively on the MicroSat-70 heritage, the enhanced microsatellite provided substantially greater payload power and volume to match emerging customer requirments. It included orbit station-keeping for constellation applications, and an advanced attitude control system using reaction wheels and control moment gyros for agile and precise pointing. A typical configuration (as used on three Disaster Monitoring Constellation satellites) included 2 Gbytes of on-board storage and dual-redundant 8-Mbit/sec S-band downlinks.

The MicroSat-100 structure was based on the same modular principles as the MicroSat-70. The internal module stack was mounted on larger facets providing accommodation for additional avionics, propulsion and payload subsystems. The volume above the stack was available for payloads, and was generally configured as an Earth-facing aperture.

The MicroSat-100 was proven in orbit by the AlSAT-1 mission, and further units were launched in 2003. The MicroSat-100 provided a proven baseline for customisation, or an exceedingly cost-effective off-the-shelf solution for LEO remote sensing missions.

Typical orbit: 662 km circular orbit, 98 deg inclination. Mass: 50 kg (110 lb). Associated Launch Vehicle: Ariane 4, Kosmos 11K65M.

• 1995 July 7 - CERISE - Launch Site: Kourou. Launch Vehicle: Ariane 4. Mass: 50 kg (110 lb). Perigee: 666 km (413 mi). Apogee: 675 km (419 mi). Inclination: 98.10 deg. Period: 98.10 min.

  Caracterisation de l'Environnement Radioelectrique par un Instrument Spatiale Embarque; examined Earth RF environment. Customer: Alcatel Espace/DME. French government research payload incorporated into an advance microsatellite platform. Still operational as of 2000.

• 1999 December 3 - Clementine - Launch Site: Kourou. Launch Vehicle: Ariane 4. Mass: 50 kg (110 lb). Perigee: 646 km (401 mi). Apogee: 664 km (412 mi). Inclination: 98.10 deg.

  Customer: Alcatel Espace(France). French government military electronic intelligence research payload incorporated into an advance microsatellite platform. Based on CERISE with enhanced EMC subsystem. Still operational as of 2000.

• 2003 September 27 - BNSCSat 1 (DMC-UK) - Launch Site: Plesetsk. Launch Vehicle: Kosmos 11K65M. Mass: 80 kg (176 lb). Perigee: 677 km (420 mi). Apogee: 694 km (431 mi). Inclination: 98.20 deg. Period: 98.50 min.

• 2003 September 27 - NigeriaSat 1 (DMC-Nigeria) - Launch Site: Plesetsk. Launch Vehicle: Kosmos 11K65M. Mass: 80 kg (176 lb). Perigee: 677 km (420 mi). Apogee: 694 km (431 mi). Inclination: 98.20 deg. Period: 98.50 min.

• 2003 September 27 - Bilsat 1 (BiltenSat, Tubitak 1, DMC-Turkey) - Launch Site: Plesetsk. Launch Vehicle: Kosmos 11K65M. Mass: 100 kg (220 lb). Perigee: 677 km (420 mi). Apogee: 695 km (431 mi). Inclination: 98.20 deg. Period: 98.50 min.

  Three disaster monitoring DMC satellites (BILSAT-1, NigeriaSat-1 and UK-DMC) were lofted in a single Kosmos launch. They joined the first DMC satellite, AlSAT-1, which was launched into a 686 km sun-synchronous low Earth orbit in November 2002, to provide a worldwide daily imaging capability. The spacecraft were 3-axis stabilised nadir-pointing. The imaging payload was a 32-metre resolution GSD multispectral wide-swath Earth imaging cameras and a12-metre GSD panchromatic camera. The Kosmos rocket delivered the satellites into orbit with a precision about an order of magnitude better than the maximum allowable - placing the satellites into orbit with a semi-major axis accurate to within 700 metres and just 300 metres from that of AlSAT-1. Bilsat 1 was built for TUBITAK-ODTU-BILTEN, the Information Technology and Electronics Research Institute of the Middle East Technical University, Ankara, Turkey

• 2005 October 27 - Topsat - Launch Site: Plesetsk. Launch Vehicle: Kosmos 11K65M. Mass: 108 kg (238 lb). Perigee: 682 km (423 mi). Apogee: 707 km (439 mi). Inclination: 98.20 deg. Period: 98.70 min.

  Delayed from May 18, mid-July, August 25, September 27 and 30, 2005. UK military surveillance research satellite.

• 2005 October 27 - Beijing-1 - Launch Site: Plesetsk. Launch Vehicle: Kosmos 11K65M. Mass: 140 kg (300 lb). Perigee: 682 km (423 mi). Apogee: 705 km (438 mi). Inclination: 98.20 deg. Period: 98.60 min.

  Beijing-1 carried a 31-cm focal-length cartographic telescope with a resolution of 4 meters. It was to be part of the international Disaster Monitoring Constellation. Operated by Tsinghua University for Beijing Landview Mapping Information Technology Ltd.

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