Resurs-O

The year 1994 witnessed the long-awaited debut of the Geostationary Operational Meteorological Satellite (GOMS) system of Elektro spacecraft. Originally proposed for a maiden flight in 1978-1979, GOMS has suffered both technical and budgetary problems. The objectives of the program, as stated in 1991, are as follows:

• "a to acquire, in real time, television images of the Earth surface and cloud within a radius of 60 degrees centered at the sub-satellite point in the visible and IR regions of the spectrum;
• to measure temperature profiles of the [Earth surface (land and ocean) as well as cloud cover;
• to measure radiation state and magnetic field of the space environment at the geostationary orbital altitude;
• to transmit via digital radio channels television images, temperature and radiation and magnetrometric information to the Main and regional data receiving and processing centers;
• to acquire the information from Soviet and international data collection platforms (DCPs), located in the GOMS radio visibility, and to transmit the obtained information to the main and regional data and processing centers;
• to retransmit the processed meteorological data in the form of facsimile or alphanumerical information from the receiving and processing centers to the independent receiving stations via satellites;
• to provide the exchange of high-speed digital data (retransmissions via the satellite) between the Main and regional centers of the USSR State Committee for Hydrometeorology;
• to call for the data collection platforms to transmit the information to the satellite." (Reference 661).

In addition to the meteorological and oceanographic satellites described above, the Russian Federation has operated seven different types of spacecraft since 1991 to perform awide variety of global remote sensing observations. More advanced spacecraft are already in the design and development phase for possible missions later in this decade. However, together the satellites represent a level of redundancy which suggests that, in the difficult financial conditions now present in the Russian Federation, not all spacecraft classes will continue to be supported.

The Resurs-O program, which is analogous to the US Landsat program, became operational in 1985 after more than ten years of on orbit testing. Designed and manufactured by the All-Union Research Institute for Electromechanics, the Resurs-01 spacecraft, not surprisingly, closely resemble the Meteor series of satellites from which they were derived. In fact, the Resurs-O development program utilized two Meteor satellites (Meteor 1-18 and Meteor 1-25) and five Meteor-Priroda vehicles (1977-1983) to perfect the instruments and techniques finally adapted for Resurs-01. The Meteor-Priroda satellites also marked the first use of sun-synchronous orbits by the USSR.

Program management for the Resurs-O effort was originally the responsibility of the State Committee on Hydrometeorology. In 1989 the Planeta NPO was formed under this organization to consolidate the meteoro-logical and remote sensing satellite systems of the USSR. Subsequently, the Planeta NPO, the All-Union Research Institute of Electromechanics, and the Space Instrument Building NPO, which was responsible for many of the payload instruments, formed the Soviet Association for Earth Remote Sensing (SOVZOND) to promote Resurs-O products on a commercial basis.

Resurs-O spacecraft are placed into nominal orbits of 630 km altitude and an inclination of 98 degrees. Each mission is conducted to ensure that the spacecraft's descending node will occur between 10:00 and 10:30 a.m. local sun time, thereby providing excellent lighting conditions for the complex sensor suite. The objectives of the Resurs-O program are as follows:

• "a to obtain in both real-time and store-and-forward modes multi spectral sensor information with medium and high resolution invisible and IR bands to provide data for land and ocean states in any region of the globe;
• to obtain in the same modes the all-weather relay images of the land ocean with medium resolution;
• to process the obtained data and images, and to perform their radiometric, geometric and geographical correction;
• to represent and distribute the obtained data in the form of single-spectral and synthesized multi spectral images on the photos, negatives, and digital recordings on the various media (tapes, diskettes); and
• to obtain and disseminate thematic maps and charts concerning various aspects of Earth natural resources exploration, environmental control and ecological monitoring" (Reference 670).

The Resurs-01 spacecraft bus is almost identical to that of the Meteor 3 vehicle with a total mass of 1,840-1,910 kg, including a payload of up to 600 kg. The spacecraft diameter is 1.4 m with an overall height of 6.4 m and a solar array span of 11.6 m. The payload support structure at the base of the spacecraft is tailored for each mission to accommodate the specific instruments to be carried. For example, of the three primary instruments available, the first Resurs-01 (Kosmos 1689) was out-fitted with two MSU-E, one MSU-SK, and one MSU-S devices, while the second Resurs-01 (Kosmos 1939) omitted the MSU-S and carried two MSUE and two MSU-SK. The 30-kg MSU-E employs an electro-optical COD scanner for high resolution and can be used in pairs to provide a continuous 80-km wide swath. On the other hand,the mechanical MSU-SK scanner weighs 60 kg and combines a lower resolution capability with a much wider swath. (References 183-192).

The primary data collection and processing stations for Resurs-O are the same as for Okean: Moscow, Novosibirsk, and Khabarovsk. The principal data transmission link is also similar at 466.5 MHz. A standardized small receiving station, utilizing a 2.5 m diameter antenna and the Spektr-DK01 system, has been designed for use with both Okean and Resurs-0 spacecraft when the data links are upgraded to the new 8.2 GHz system (Reference 193).

Kosmos 1939 (April, 1988) had far exceeded its design lifetime of one year and was still operational when it was joined by Resurs 0-1 on 4 November 1994. Unlike earlier Resurs-01 type spacecraft which had been launched by Vostok boosters from the Baikonur Cosmodrome, Resurs 0-1 was launched by a Zenit-2 booster and was inserted into an orbit of 661 km by 663 km with an inclination of 98.0 degrees. The spacecraft mass of 1,907 kg was slightly higher than earlier models and included an attached German SAFIR-R payload. The principal Earth observation sensors were MSU-SK and MSU-E instruments along with an experimental PVM-E local vertical sensor (References 681-687).

Originally scheduled to replace Resurs-01 in late 1992, Resurs-02 represents an evolutionary improvement of the Resurs-O system which adds both a synthetic aperture radar (SAR) and a microwave radiometer capability (Figure 4.84 and Table 4.8). Resurs-02 not only will be heavier (2,400 kg with a payload of 900 kg) but also may be placed in a higher, 830-km orbit to increase its coverage potential. A Resurs-02 variant specifically designed for Arctic surveys is also under consideration.

The Resurs-02 payload will be able to draw up to 800 W daily with a peak power of 2 kW. The data transmission system will operate at 8.2 GHz to the main receiving and data processing center at Moscow and the regional centers at Novosibirsk, Tashkent, and Khabarovskas well as with smaller, local stations. On-board data storage capacity will also be increased markedly.