ASM
Thailand Launches Theos
After nearly two years of delays, Thailand has become the newest country to achieve space observation capability, with the successful launch of Theos (Thai Earth Observation System) on 1 October 2008.
The satellite was successfully placed into a transfer orbit by a Russian-Ukranian Dnepr rocket launched from an undeground silo at the Yasny space base in southern Russia.
Theos has been placed into a 690 km parking orbit. After initial tests at that orbit for several days, Theos will use its onboard propulsion to reach its operating orbit at 822 km, inclined at 98.7 degrees relative to the equator.
The 750 kg Theos satellite was designed and manufactured by French company EADS Astrium under a 2004 contract with the Thai Ministry of Science and Technology. Astrium was responsible for all phases of the satellite’s journey into orbit, from manufacture to launch. The contract also included the development of the ground segment necessary to operate and control the satellite directly from Thailand, and facilities for image archiving and processing.
Astrium and Thailand's space agency, Geo-Informatics and Space Technology Development Agency (GISTDA), embarked on a major co-operation and training program as part of the project. Thai engineers joined the Astrium development team and attended intensive space program training. The aim is to further develop the human resource capabilities of GISTDA and space activities in Thailand.
The Theos payload features two optical imagers: one high resolution (2 metres) panchromatic mode, with a swath of about 22 km; the other with a 90 km swath width and 15 metre resolution in multi-spectral mode. The satellite is designed to operate for five years, but has enough fuel for at least seven years.
The craft has worldwide imaging capability and will provide access to any part of Thailand in less than two days. The imagery will be used in applictions in cartography, land use, agricultural monitoring, forestry management, coastal zone management and flood risk management.
Theos’ launch was initially planned for early 2007, but the contract with the Russian-German Eurockot Launch Services was abandoned due to parts shortages.
GISTDA then turned to Kosmotras, the international company that manages Dnepr launch operations. But the launch – now planned for early 2008 – was again stalled when Russia failed to secure compensation agreements with countries south of the Yasny launch site. These included Kazakhstan, Uzbekistan and Turkmenistan.
To reach its target orbit, Theos had to launch on a southerly trajectory on a flight path never before attempted from that site. Engineers had planned to drop the first stage of the Dnepr rocket in Uzbekistan. When negotiations with that country failed, they were forced to redesign the rocket's trajectory to drop the first stage in Kazakhstan.
Kazakhstan's national space agency authorised the new drop zone in June 2008.
Russian military officials advised Kazcosmos of the rescheduled 6 August launch two days before lift off, but Kazakhstan refused to authorise the launch. A further two months of negotiations finally resulted in the 1 October launch.
One industry official reportedly told Space.com that Kosmotras' difficulties in securing launch authorisation were likely to continue. This, combined with a sharp increase in Kosmotras launch prices, ‘would cause owners of Earth observation and other small satellites to look for other options'.
