Chinese Long March 4C launches Yaogan-19 Remote-Sensing Spacecraft
November 20, 2013
The real purpose of the satellites is likely optical surveillance and tracking warships by acquiring their optical signatures and radio transmissions.
Yaogan Satellites either carry an optical imaging payload, a Synthetic Aperture Radar payload or an Electronic Intelligence package. Satellites carrying an optical imager were developed by the Shanghai Academy of Space Flight Technology while the SAR spacecraft were developed by the China Academy of Space Technology.
The first Yaogan satellite was launched on April 27, 2006 by a Long March 4B blasting off from Taiyuan. The Yaogan-1 satellite was found in a 636-Kilometer orbit at an inclination of 97.9 degrees, but details on the satellite were a closely guarded secret. Later, it became known that the spacecraft was equipped with the first space-based Synthetic Aperture Radar payload.
Yaogan-2 was launched on May 2007 by a CZ-2D lifting off from Jiquan. It settled in a similar orbit, slightly higher than Yaogan-1, but also with a 97.9-degree inclination. Details on the spacecraft were once again restricted, but it was claimed that this satellite was carrying an electro-optical imaging payload to complement the data acquired by Yaogan-1.
Also in 2007, Yaogan-3 was launched. It featured a design identical to that of Yaogan-1 and was delivered to an identical orbit, using a Long March 4C launching from Taiyuan. In 2008, two optical satellites were launched – one from Jiquan atop a Long March 2D and one aboard a CZ-4B from Taiyuan. The second of those two satellites settled in a lower orbit and is suspected to be a second generation electro-optical satellite.
2009 featured three Yaogan launches including the first second-generation SAR satellite known as Yaogan-6 that was launched in April by a Long March 2C. Two optical satellites were launched in December 2009: Yaogan-7 – a first generation optical satellite and Yaogan–8 that carried a new type of optical payload. Yaogan-8 was delivered to an orbit at an altitude of more than 1,000 Kilometers at an inclination of 100.5 degrees.
After the Yaogan-9 payload had arrived in orbit, analysts were in for a surprise as three spacecraft were detected flying in a highly choreographed, triangular constellation in a 1,080 by 1,100-Kilometer Orbit at an inclination of 63.4 degrees - resembling the US NOSS triplets that were used for ELINT purposes until being replaced by duos of NOSS (Naval Ocean Surveillance System) starting to be launched in 2001.
Yaogan-10, a first-generation SAR satellite, was launched in August 2010, followed by Yaogan-11 in September which was a first generation optical spacecraft. In 2011, another two Yaogan satellites were delivered to orbit – one equipped with a 2nd generation optical and the other with a 2nd generation SAR payload.
It uses a 98-Kilonewton YF-40 Rocket Engine. YF-40 has a dry weight of approximately 166 Kilograms and a diameter of 0.65 meters. It provides re-ignition capability to the vehicle in order to target a variety of orbits and provide precise injection capabilities.
Long March 4C is capable of delivering payloads of up to 4,200 Kilograms to Low Earth Orbit. Sun Synchronous Orbit capability is 2,800 Kilograms and Payloads of up to 1,500 Kilograms can be delivered to Geostationary Transfer Orbit by the Long March 4C.