Cold War paranoia may have eased up on the Space Race decades ago, but a new report finds that military projects still take up nearly half of all spending worldwide on space assets.

The United States is by far the biggest spender on defense-related space programs, yet its technical savvy also makes it the country most dependent on such systems, according to a report, "Space Security 2010," released in September.

American efforts to project military power across the globe have helped drive such dependence on space power, said military and security analyst John Pike, who runs GlobalSecurity.org.

"If we want to blow somebody up, we have to go to the other side of the planet, and need lots of space support to do so," said Pike, who was not involved in compiling the report. [Most Destructive Space Weapons Concepts]

That dependency may leave the U.S. most vulnerable to anti-satellite measures aimed at taking out the country's watchful orbital platforms. While the U.S., China and Russia have perhaps the most advanced capabilities for destroying satellites, India also has announced plans to develop anti-satellite capabilities.

Eyes in the Sky

According to the new report, the U.S. Department of Defense allocated $10.7 billion to boost space-based capabilities in 2009. But that figure did not include money for the National Reconnaissance Office, National Geo-Spatial Agency, or Missile Defense Agency.

Much of that defense spending focused on satellites that provide services such as communications, intelligence, reconnaissance and surveillance, as well as weather forecasting, navigation and weapons guidance applications.

The United States operated about half of the world's 175 dedicated military satellites that were in space at the end of 2009, according to the Space Security Index, an international research consortium that compiled "Space Security 2010."

Pike considered that count of U.S. military satellites "significantly low," and said a count of 115 satellites by the Union of Concerned Scientists came much closer. Russia was said to operate a quarter of the military satellites with 38, and China had 12.

The Russian number "sounds about right," Pike said in an e-mail. He pointed out it is just a third of the total number of Soviet military satellites that were aloft during the Cold War.

U.S. dependence on space power goes far beyond dedicated military satellites. Many of its navigational and targeting systems also depend on Global Positioning System satellites that guide civilian smartphone users and drivers.

The Air Force launched the first of a planned fleet of 12 ultra-precise GPS satellites in May.

Russia has pushed forward its own GPS satellite constellation, called the Global Navigation Satellite System (GLONASS). That has its own budget of $1 billion.

Shoot-down Systems

The U.S., China and Russia currently have the most-advanced ground-based missile systems that can destroy satellites, according to the report; the U.S. and China demonstrated theirs in recent years.

In 2007, China shot down an ailing weather satellite with a ground-launched missile, and the U.S. Navy shot down a defunct spy satellite with a ship-launched missile in 2008.

Russia showed indications of anti-satellite capabilities in the 1980s.

Such countries also have access to advanced laser programs that could temporarily dazzle or blind the sensitive optics of satellites in low-Earth orbit.

During the Cold War, both the U.S. and Russia tried to develop space-based strike systems that could attack Earth targets with nuclear weapons or lasers. But countries appear to have moved away from such "Star Wars" systems in recent years. The U.S. space-based missile interceptor programs have faced funding cuts as well, and so the U.S. military has focused instead on ground or airborne lasers.

Future of Space Power

Some space technologies or capabilities may or may not have military possibilities, depending on different national intentions and viewpoints.

China's recent secret satellite maneuvers probably represented tests of future space rendezvous capabilities, analysts said. Yet a Russian news story suggested China could use similar maneuvers to inspect foreign satellites.

The U.S. Air Force's X-37B space plane, currently orbiting the Earth, might allow the U.S. military to quickly replace satellites knocked out during a conflict. The space plane, too, has drawn speculation about secret military weapons, but such a role looks unlikely to analysts.

For now, the United States appears likely to remain in the lead for space capabilities that support the military. That comes in part from its current goal of maintaining military might around the world.

"Until China discovers an urgent need to defend the Panama Canal from the Yanqui Imperialists, I don't see (it) developing global power projection capabilities of which space is an integral component," Pike wrote.

Its reliance on space capabilities leaves the U.S. military more alone in terms of vulnerability, if future adversaries decide to knock out supporting satellites.

"Space Security 2010" suggested that Russia also has an interest in preventing the development of systems that could threaten satellites, but Pike disagreed.

"Russia does not have a China threat scenario, so I don't think they care," Pike said.

This article was reprinted with permission from SPACE.com.

Related from Space.com