A North Korean satellite launch that ended in failure will provide a trove of information about the secretive state’s rocket program as South Korea salvages large sections from the bottom of the sea.

South Korea on Friday released photos of a 14.5-meter (15-yard) portion of the North Korean rocket that failed in flight shortly after takeoff on May 31. South Korea’s military said the two pieces it recovered in waters about 70 meters deep were likely from the second stage of the rocket that failed to ignite.

North Korea claimed the second stage contained a new engine and its failure may have been attributable to the “unstable character of the fuel used.” But the discovery by South Korea will likely give clues about the state’s proficiency in engine design and perhaps point to components that may have made their way to Kim Jong Un’s regime through sanctions violations.

“Anyone with access to that rocket part, and a good understanding of rockets, should be able to derive all technical data, performance data, and the manufacturing capabilities of the North Koreans from that hardware, including the meaning of proliferation for their whole program,” said Markus Schiller, an aerospace engineer who founded the ST Analytics consultancy in Germany that specializes in space technology.

The salvage operation will likely end up being the most significant by the outside world on a North Korean rocket.

The first stage of the rocket North Korea dubbed “Chollima-1,” in reference to a mythological winged horse, is suspected to have used liquid-fuel engines. The regime has also deployed those engines in its most powerful intercontinental ballistic missiles designed to deliver nuclear warheads to the US mainland.

The second and third stages were of a smaller diameter and it is uncertain how they would have been fired to place North Korea’s first spy satellite into orbit.

North Korea called the satellite launch one of its “most serious” failures this year during a Central Committee meeting of its ruling Workers’ Party and pledged to put another one into orbit soon, state media said Monday.

A cross reference of the salvaged pieces shown by South Korea and images of the rocket provided by North Korea reinforce indications of the second stage being recovered, said Joseph Dempsey, a research associate for defense and military analysis at the International Institute for Strategic Studies.

“The most significant element South Korea could glean from this section is the engine,” he said. “If recovered, it could indicate the origins of the design, potentially highlighting further sanction violations.”

Under Kim, North Korea has been increasing the domestic technology and components that go into his newest array of missiles. The country still needs the outside world for certain materials and components, which it is barred from acquiring under global sanctions to punish it for its pursuit of nuclear weapons and ballistic missiles to deliver warheads.

The US has accused North Koreans in countries such as China and Russia of providing materials needed for missile production. The US placed sanctions on two North Koreans residing in Beijing it accused of such activity, in an announcement that came hours after the regime fired off two, short-range ballistic missiles on June 15, in violation of United Nations Security Council resolutions.

Pyongyang has fired 19 ballistic missiles so far this year, including three ICBMs, and tested a new array of systems to deliver strikes to South Korea and Japan, which host the bulk of US troops in the region.

David Schmerler, a senior research associate at the James Martin Center for Nonproliferation Studies, said the recovery of the rocket sections will help in finding out what materials went into its construction, possibly including foreign parts.

“If they do find parts not made domestically in North Korea, steps can be put into place to prevent the North from acquiring them in the future,” he said. “It would also help to identify the state of North Korea’s ability to produce parts in country.”

South Korea is pressing ahead with its salvage efforts, trying to find more pieces of the rocket, including the third stage that holds the spy satellite. While what has been recovered so far may have exposed vulnerabilities, it’s unlikely to deter Pyongyang from forging ahead with its missile and satellite program, said Soo Kim, a former Korea analyst at the US Central Intelligence Agency.

“The regime is quite thick-skinned and brazen-faced in the face of its vulnerabilities, so this incident should still leave Kim unfazed and unshaken in his determination to sophisticate his country’s weapons program,” said Soo Kim, who now works at US-based management consulting firm LMI.

Recovering the spy satellite could provide a bonanza of information from the components that went inside to just how high the resolution would be of the camera on the spy satellite.

Sejin Kwon, professor of aerospace engineering at the Korea Advanced Institute of Science and Technology, said South Korea may have already recovered the third stage of the rocket, and is handling the matter with care.

“I believe that if the military has pulled out the upper part of the rocket, they would have found the satellite intact in the pairing of the recovered wreckage.” he said.

--With assistance from Shinhye Kang and Seyoon Kim.

(Updates with North Korea media report in eighth paragraph.)