New alarms are sounding over signs that China may be developing space weapons, reinforcing suspicions that the People's Liberation Army is increasingly interested in the final frontier as a theater of war.

The latest alert came Thursday from an independent panel - created by Congress to assess the economic and security situations in China - that questions Chinese intentions and urges lawmakers to lean on the Bush administration to talk with Beijing about curtailing space militarization.

Specifically, the annual report of the US-China Economic and Security Review Commission urges the US to emphasize to China the merits of "strategic warning and verification measures" - in essence, the value to both sides of leaving early-warning and spy satellites unharmed.

To be sure, space has been militarized since the United States and the former Soviet Union launched the first reconnaissance satellites during the cold war. Nowadays, US intelligence services are intent on teasing out information on China's military space program, and their findings are a staple of Pentagon reports to Congress on threats to US security.

Concerns about China's intentions rose in September, with a report that China in recent years has tested a ground-based laser against US reconnaissance satellites. The presumed aim: to be able to blind them, temporarily or permanently. The report, published in Defense News, suggested that the Bush administration has been mum on the issue because it needs China's help in dealing with North Korea's nuclear-weapons program.

A mysterious incident of concern

In addition, members of the Senate Intelligence Committee have taken note of a recent incident "that has them very concerned," says Gregory Kulacki, a China specialist for the Union of Concerned Scientists' Global Security Program. Members wouldn't disclose details, he continues, so "we're not sure what it is, but they said it didn't involve lasers."

The incident might involve tests of a solid-fuel rocket the Chinese are developing, Dr. Kulacki speculates. China tested an early model, dubbed the KT-1, in 2002 and 2003. The tests reportedly failed. But China has pressed ahead, developing a follow-up KT-2. It's a three-stage rocket designed to loft nearly 1,800 pounds into low-Earth orbit. Such a rocket would be capable of launching minisatellites aimed at disabling US satellites, he adds. Moreover, perfecting solid-fuel, multistage motors could also allow China to build smaller, antisatellite rockets that could be launched from a jet fighter - similar to the three-stage weapon the US tested in 1985.

Some specialists argue that China's efforts require the US to forge ahead with its own antisatellite weapons and space-based defenses against nuclear-tipped ballistic missiles. Others suggest that Chinese space-weapons programs are nascent - in some cases residing only in the imaginations of young officers in the People's Liberation Army writing for military journals. Thus, they say, the US can still try to influence the direction of China's programs through diplomacy and greater cooperation between the two space programs.

Regardless of where one stands on the issue, "we should view this very seriously," says Larry Wortzel, chairman of the US-China Commission.

US prowess: a motivator for China?

China's moves may be motivated in large part by US capabilities and policies. US military successes in the first Iraq war, the Balkans, and the early stage of the current war in Iraq were not lost on Chinese military planners, who noted the key role of US spy and navigation satellites in planning and precision bombing. If China ever confronted the US military, they saw, it would need a way to offset the Pentagon's high-tech advantage on orbit.

In August, the White House issued a new national space policy that puts more emphasis on "unhindered US operations in and through space to defend our interests there." The policy also opposes any international pact that would limit US space research or operations. China and Russia are part of a group of countries that supports a global ban on weapons in space.

Divining Chinese intentions is tough, analysts agree, and the difficulty of piercing the bamboo curtain can lead to misinformation. Kulacki, of the Union of Concerned Scientists, recalls efforts to track down reports that China was developing a "parasitic" satellite that could sidle up to another satellite and explode or jam it. The "program" was listed in some Pentagon reports, but he and a colleague tracked it to a blog maintained in China by someone professing an interest in the Chinese military's use of space.

One way to try work around the lack of information, Dr. Wortzel says, is for the two militaries to agree on rules for behavior in space and for addressing suspicious events. During the cold war, he notes, the US and the Soviet Union agreed to keep hands off each other's reconnaissance and early-warning satellites - even as they researched antisatellite weapons. That's still the practice, he says. The Chinese have approached the State Department on this issue, with no success so far, he adds.

Starting a dialogue on military-space issues, however, "will be very difficult in the absence of scientific, educational, and commercial cooperation," cautions Kulacki. Until those exist, he says, prospects for agreement on the military use of space will remain slim.