Iran's announcement that it launched a research rocket has called new attention to a space program that Tehran says 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, or even what it aimed to do, remains the subject of debate, speculation and possible misinterpretation.
But there are parallels to the controversy over its nuclear program.
Capabilities remain unknown
Some experts say that in both cases, what Iran says is a peaceful program could mask or be transformed into a weapons program. And in both cases, 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 announcement on 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. The United States has not commented officially.
State Department spokesman Sean McCormack would not discuss details of U.S. intelligence on the launch, but he said the United States remained troubled by Iran's activities.
"We do have outstanding concerns about Iran's missile program and we are very much concerned about the possible nexus between that program and their nuclear ambitions," he told reporters.
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.
Similar technology
The announcement raised eyebrows because experts say there is little difference between the technology needed to construct an SLV 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 John Sheldon of the School of Advanced Air and Space Studies at Maxwell Air Force Base in Montgomery, Ala.
Given such similarities, some in Israel have expressed grave concerns. Former Prime Minister Benjamin Netanyahu said after Iran's suborbital rocket announcement: "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 say Iran is far from such a goal.
Improved range
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 1,200-1,900 miles, which 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.
Iran initially acknowledged in 1999 it was developing the Shahab-4, but said it would be used only as a space launch vehicle for commercial satellites.
In 2003, Tehran declared it had ended the Shahab-4 program. But Western intelligence agencies doubt this, and Sheldon added, "We know there is a missile that seems to be significantly bigger than the Shahab-3."
Increased allocation for space projects
At the same time, Iran has made no secret of major ambitions for its space program. In 2005, the government said it had allocated $500 million for space projects in the next five years. Also in 2005, Iran launched its first commercial satellite, Sina-1, into orbit from a Russian rocket.
On Feb. 24, Defense Minister Mostafa Najar confirmed that Iran is now constructing its own satellites and the rockets to launch them.
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 try to launch an ICBM/SLV by the second half of this decade.
Craig Covault of 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 nonproliferation 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."
'Interest in making Iran bigger'
Mustafa Alani, a military analyst with the Dubai-based Gulf Research Center, said the Iranians' statements are merely intended to build domestic support — and he blames the West for buying them.
He said the U.S. and Israel "have an interest in making Iran bigger" than it is so they have a justification for striking it.
Nevertheless, 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.
Dareini reported from Tehran and Abbot from Cairo, Egypt.