"Much of the water space [in the South China Sea] is more than 2,000 fathoms deep," said Dutton.
Detecting submarines via satellite is a form of Non-Acoustic Anti-Submarine Warfare (NAASW). Lasers, infrared and other detectors and synthetic aperture radar (SAR) in space may be used as part of this NAASW activity. Satellites might see subtle undersea disturbances caused by submarines, watch wave patterns on or beneath the sea surface, or detect subtle variations in ocean temperature.
This is not to be confused with satellite
communications, nor is an "EO" or "Earth Observation" satellite to be confused with "EO" as in an "Electro-Optical" means of detecting submarines.
Over the next 18 months, the US National Reconnaissance
Office(NRO) - operator of the US spy satellite fleet - is planning multiple satellite launches, and China must assume that one or more of these new US surveillance satellites will help support US Navy efforts to locate and track PLAN submarines.
Satellites form a network along with undersea sensors and detectors fixed on the sea floor or drifting in the open ocean as well as devices mounted on other submarines, ships, unmanned undersea vehicles (UUVs), aircraft, helicopters and unmanned aerial vehicles (UAVs).
Many are skeptical that satellites can perform NAASW missions effectively, reliably and at reasonable cost.
"The natural disturbances of the sea surface due to wind and tides, it seems to me, are very likely to mask any disturbance due to a submarine passage, and so even if this were a viable detection technique, it seems to me so limited in application that it would not be worth the investment," said one former US Navy sonar expert.
In April, a source told RIA Novosti, a Russian newspaper, that Russia had developed a novel satellite module "used for both defense and civilian purposes, in particular, providing meteorological data", and it can "carry out remote sensing of the sea and detect submerged submarines". This will be tested in space perhaps as early as next year. [1]
"Submarine detection, by any means, is a classified and highly guarded topic. The fact that the Russians are talking about it is the most interesting aspect of this announcement," said Brian Whitehouse, president of Nova Scotia-based OEA Technologies, Inc. He co-authored a paper with Daniel Hutt in 2008 about spaceborne sensors, ocean intelligence, and the maritime battlespace. [2]
The satellite in question is apparently the first of three small Russian Kanopus (Konopus) remote sensing satellites.
"This satellite is planned for 2011 and it will carry an Earth observing payload that includes a sensor for studying the underwater light environment," said Dr Jonathan McDowell, an astrophysicist at the Massachusetts-based Harvard-Smithsonian Center for Astrophysics who is also the editor of Jonathan's Space Report. "I cannot evaluate the claim that this will let them detect the wakes of submarines. I do not believe that such technology is being used operationally at the moment. I am not aware of relevant flight experiments, but they may have occurred."
Russia has previously demonstrated its satellite sub-hunting skills. Swedish satellite expert Sven Grahn identified the Russian Almaz-1 satellite which was launched in 1991 as a submarine-detection satellite that could see the surface wake or trail of a submerged sub. Besides this satellite, the Russians deployed other large, nuclear-powered and radar-equipped ocean surveillance satellites.
"Russian satellites known as RORSATs used radar to track surface ships, but the US Navy was not concerned that our subs could be detected, much less tracked. The signals, even if they existed, would be so wrapped into random noise that extracting any usable intelligence from them proved impossible," author James Oberg, a top US expert on Soviet and Russian space programs, told Asia Times Online. "The cancellation of that [Soviet] satellite program followed at least three accidental re-entries of debris. The laws of physics compelled them to orbit as low as possible, creating high air drag."
The theoretical boundary below which satellites cannot successfully maintain their orbits is approximately 160 kilometers above the Earth.
The Soviet space station Mir may have served as a platform for related research activities in the same way that the US Skylab once served as a platform for space radar testing in 1970s.
In the late 1990s, sub-hunting satellites made headlines. An American scientist, Peter Lee, was caught and convicted of passing sensitive information to China about the so-called Radar Ocean Imaging (ROI) joint project which involved the United K and the US. A decision by the US Navy based on concerns about further disclosures about the nature and scope of the ROI project echoes to this day.
"Peter Lee's case was they had this guy giving this very sensitive data to the Chinese on underwater detection of submarines. They ran into this case where the navy wouldn't allow a court case against him because of the data. So they had a bargain plea, and he got off, basically. For stealing very high-level stuff, he gets probably, what, a couple of months in a halfway house," former US ambassador to China, James Lilley, told PBS in 2004. [3]
China obtained relevant information from Russia, too.
"Chinese experts reportedly received technical assistance from Russian satellite experts in years following the Soviet Union's collapse," said associate professor Andrew Erickson at the China Maritime Studies Institute. "Specialists at the State Key Laboratory of Satellite Ocean Environmental Dynamics have researched ship detection using [SAR]."
Maritime surveillance became a top priority at the national level when China's so-called, "863 State High-Technology Development Plan" was activated. And China's fleet of Haiyang ocean surveillance satellites will grow to three when Haiyang-2A is launched later this year
Prior to the ROI program, the US SEASAT ocean satellite project which was launched by the US National Aeronautics and Space Administration (NASA) in 1978 carried a SAR into space for maritime surveillance purposes. After just over 100 days in space, SEASAT suddenly stopped working due to a short circuit in the design of its solar panels.
"Rumors suggested it had been turned off or sabotaged. There was a claim that SEASAT had mapped a field of World War 2-era shipwrecks on the floor of the English Channel," said Oberg.
A US Navy oceanographer from Australia, Paul Scully-Power, who became the first oceanographer in space, flew on the space shuttle Challenger (STS - 41G) in 1984. The US Navy later admitted that the mission had successfully detected the undersea or internal waves generated by a submarine which had been tracked successfully at relatively shallow depths. This was deemed, "incredibly important to us" and was reported by the Washington Post in 1985 - quoting a senior US Navy admiral at the time. [4]