WASHINGTON — Foreign nationals did indeed have access to restricted defense technology at NASA’s Ames Research Center in 2008 and 2009, but it is impossible to tell if they shared technical details about that technology with anyone overseas, the Pentagon’s Office of the Inspector General reported July 13.

The IG’s investigation, ordered by Congress in a report accompanying a 2015 defense authorization bill, is the latest development in an export-control flap at the Mountain View, California, field center dating back to 2013, when a whistleblower whose identity has never been confirmed touched off a congressional inquiry over the possible transfer of classified military technology at Ames.

The hardware at issue, which the IG said was not classified, is a Divert Attitude and Control Subassembly (DACS): a small, rocket-propelled steering system built by Raytheon Co. for the Missile Defense Agency’s now-defunct Multiple Kill Vehicle — a missile-intercept payload designed to destroy incoming warheads using several steerable, rocket-powered bullets.

The Pentagon legally transferred a spare DACS to NASA in 2007 at the request of retired Air Force Brig. Gen. Simon “Pete” Worden, who served as director of Ames from May 2006 to this past March. Two classified subsystems, a seeker assembly and communications hardware, were removed from the DACS before NASA took possession of the unit.

Worden, an Air Force Space Command veteran who once managed the technology portfolio for the Missile Defense Agency’s predecessor organization, wanted to incorporate DACS technology into a low-cost lunar-lander concept Ames was working on.

Although the DACS was stripped of its classified components by the time NASA got it, exporting the unit remained illegal under the U.S. Internal Traffic in Arms Regulations (ITAR), which hold that unauthorized access to controlled technology, even on U.S. shores, counts as an export.

“Subsequent to the completion of the transfer in January 2008, NASA officials allowed two foreign national contractors unauthorized access to ITAR-controlled missile technology in violation of the ITAR,” the Pentagon inspector general wrote in its report. However, “There was insufficient evidence to determine whether DoD ITAR-controlled missile defense technology was retransferred beyond the control of the U.S. Government.”

In April, the IG brought these findings to the U.S. Attorney’s Office for the District of Columbia, National Security Division, which “declined prosecutorial interest due to potential violations occurring outside the 5-year statute of limitations as well as insufficient evidence of a willful violation of U.S. export laws,” the IG wrote.

NASA spokesman Allard Beutel emphasized the IG’s finding that NASA did not transfer, or even expose, any classified technology to foreign nationals.

“That said, NASA has recognized the growing threat of cyber-attacks and espionage aimed at government agencies by hostile nation-states and foreign adversaries. And during the last several years, the agency has taken a number of actions to secure sensitive, export-controlled information at NASA facilities,” Beutel wrote in a July 24 email.

To secure the spare DACS, Worden reached out to his Air Force colleague Richard Matlock, then director of the Multiple Kill Vehicle program office, the Pentagon IG said. The DACS arrived at Ames in 2008 and was subsequently seen by one British citizen and one German citizen, neither of whom had the proper clearance at the time to even look at the equipment, according to the IG.

The report did not name the British or German men or say for whom they worked.

Between 2008 and 2009, the British citizen collected more than 200 photographs of the DACS on his laptop and shared the images over email, the IG said. Furthermore, the IG said, the British man took his laptop to a meeting in Vienna in 2009.

The British man also took the laptop to his home in the United Kingdom, although the IG found no evidence, either on the laptop itself or from interviews conducted with Ames personnel in February 2015, that any DACS photos on the laptop were shared during this overseas trip. However, a thorough analysis of the laptop was impossible, the IG said, because its hard drive was corrupted by the time Pentagon investigators examined it.

Meanwhile, the German citizen saw the DACS in 2009 while he was working on NASA’s Lunar Atmosphere and Dust Environment Explorer mission, according to the IG.

The German man was present when the DACS was removed from a storage crate so employees of Stellar Exploration of San Luis Obispo, California, could remove a part of the system for NASA-funded tests authorized by a pair of Small Business Innovation Research grants.

While that counted as an ITAR violation, the IG said, a more bizarre incident involving the German man and the DACS did not.

In September 2014, the German man brought the DACS home with him after finding it left unattended outside his office in an unlocked Pelican case. Since he had become a permanent U.S. resident alien in 2010, the DACS’ roughly three-month stay at the German man’s California home did not count as an export control violation, the IG said.

In 2013, when the Ames ITAR allegations were fresh, Worden said he had never been under investigation for export control violations and touted a successful audit of more than 100 ITAR-sensitive programs as evidence of the center’s compliance.

The DACS, according to the Pentagon IG, remains at Ames.