Iran's claim to have launched a research rocket a week ago has called new attention to a space program that Tehran claims is peaceful, but which some fear aims to produce long-range ballistic missiles that could reach Europe or the United States.

Exactly what Iran launched a week ago, or even what it aimed to do, remains the subject of much debate, speculation and possible misinterpretation.

But there are startling parallels to the controversy over its nuclear program.

In both cases, what Iran claims is a peaceful program could mask or be transformed into a weapons program, some experts say. In both cases also, Iran's actual capabilities and the speed at which they are improving remain largely unknown.

"Initially, it seemed like a cover story for an unsuccessful satellite attempt," said John Pike of GlobalSecurity.org, referring to Iran's claims Feb. 25 that it had sent a suborbital research rocket soaring to the edge of space.

Conflicting statements by Iranian officials about how high the rocket traveled reinforced that idea. But at least one U.S. defense official has privately told reporters that no launch was detected at all. Officially, the United States has not commented.

A satellite launch had been expected ever since the magazine Aviation Week reported comments by a top Iranian lawmaker, Alaeddin Boroujerdi, in January that Iran had assembled a space launch vehicle (SLV) that would lift off soon. An SLV is any type of rocket used to launch a spacecraft or satellite into orbit.

The announcement raised eyebrows because experts say there is little difference between the technology needed to construct a space launch vehicle and that needed to produce intercontinental ballistic missiles that can carry warheads.

"They use the same core technologies, with some difference in guidance systems and fuel," said Dr. John Sheldon of the School of Advanced Air and Space Studies at Maxwell Air Force Base in the United States.

Given such similarities, some in Israel have expressed grave concerns. Former Prime Minister Benjamin Netanyahu said after Iran's suborbital rocket claim: "Once they have that capability, whether for satellites or anything else, once you can boost your way up there, then you're en route to ICBMs, and that's where they're headed."

Others demur that Iran is far from such a goal.

Iran is known to possess a medium-range ballistic missile known as the Shahab-3 with a range of at least 800 miles, capable of striking Israel. In 2005, Iranian officials said they had improved the range of the Shahab-3 to 1,200 miles.

Experts also believe Iran is developing the Shahab-4 missile, thought to have a range between 2,000 and 1,200-1,900 miles, that would enable it to hit much of Europe.

Analysts believe both missiles are based on North Korean prototypes and suspect Iran has received ballistic missile assistance from Russia and China as well.

The Iranians initially acknowledged in 1999 they were developing the Shahab-4, but claimed it would be used only as a space launch vehicle to send up commercial satellites.

In 2003, Tehran declared it had ended the Shahab-4 program. But western intelligence agencies doubt these claims and Sheldon added, "We know there is a missile that seems to be significantly bigger than the Shahab-3."

At the same time, Iran has made no secret of major ambitions for its space program. In 2005, the government said it had allocated US $500 million for space projects over the next five years. Also in 2005, Iran launched its first commercial satellite, Sina-1, into orbit from a Russian rocket.

On Feb. 24 of this year, Defense Minister Mostafa Najar confirmed that Iran is now constructing its own satellites and the rockets, or space launch vehicles, to send them up.

Iran says it wants to put its own satellites into orbit to monitor natural disasters in the earthquake-prone nation and improve its telecommunications. Iranian officials also point to America's use of satellites to monitor Afghanistan and Iraq and say they need similar abilities for their security.

But Iran's potential ability to move swiftly from rockets to ICBMs has the United States concerned. In its 2001 National Intelligence Estimate, the U.S. intelligence community warned that Iran was likely to develop space-launch vehicles to establish the technical base to produce ICBMs.

It estimated that Iran would attempt to launch an ICBM/SLV by the second half of this decade.

Craig Covault, an expert with Aviation Week, said the Iranians probably could accomplish a space launch by only slightly modifying the current Shahab-3, because the U.S. used similar missiles in the 1950s for its space program.

"We used these to launch satellites, and then quickly switched to ICBMs," he said.

Not everyone agrees. Anton Khlopkov, a non-proliferation expert with the Moscow-based PIR-Center think tank, said he believes it would take the Iranians a decade to build an ICBM.

He views Iran's latest rocket launch as all "bluff ... It was an attempt to influence both the domestic public opinion and the West."

Dr. Mustafa Alani, a military analyst with the Dubai-based Gulf Research Center, said the Iranians are merely spouting propaganda to build domestic support — and blames the West for buying it.

"The U.S. and Israel have an interest in making Iran bigger than they are, so they can strike them," he said.

Despite such claims, Pike and others believe the trajectory of Iran's progress is clear, even if the timing remains uncertain. "Eventually Iran will have long-range missiles that can threaten the U.S. and Europe," Pike said.