PARIS — Boeing Co.’s petition to a Swedish court to rule on Boeing’s attempt to collect $356 million in back bills from its former Russian and Ukrainian partners in the Sea Launch commercial launch venture has been rejected, and the company on April 23 said it would now take its case to the Swedish Supreme Court.

At a time when other U.S. space companies are reassuring investors and customers that their Russian and Ukrainian suppliers will continue to deliver hardware for cash on the barrelhead, Boeing is trying to pull cash out of the same region with little apparent leverage.

In an April 23 filing with the U.S. Securities and Exchange Commission, Chicago-based Boeing said a Swedish appellate court earlier in the month ruled it could not overturn an earlier decision by the Stockholm Chamber of Commerce. Boeing initially took its case against Energia and Yuzhnoye to the Swedish Chamber of Commerce asking for an arbitration of the dispute as per the companies’ agreements surrounding the Sea Launch venture.

The chamber of commerce had said it lacked jurisdiction to determine whether Energia of Russia and Yuzhnoye of Ukraine, two big space-hardware builders, should be forced to reimburse Boeing for its advances to Sea Launch.

Boeing has been at this since 2009. When the chamber of commerce in October 2010 said it had no standing to rule, Boeing sought an appeals court judgment that would turn the chamber of commerce in another direction. The appeals court’s April decision, Boeing said, was based on the court’s assessment that an arbitrator’s decision could not be appealed.

Boeing has since quit its role as Sea Launch’s general contractor. Sea Launch went through Chapter 11 bankruptcy and emerged as a Swiss company majority-owned by affiliates of Energia.

The company, whose rockets are launched from a floating platform in the Pacific Ocean, continues to use Long Beach, Calif., as its home port, but some Russian government officials have suggested the entire operation be moved into Russian territorial waters. Such a move would better position Sea Launch to win Russian government launch business.

In parallel to its work in Swedish legal venues, Boeing in early 2013 filed suit in a U.S. District Court in California seeking the same redress. A trial date has been set for June 26.

“Our current assessment as to the collectability of these receivables takes into account the recent political unrest involving Russia and Ukraine, although we will continue to monitor the situation,” Boeing said in its SEC filing.

Peter B. de Selding was the Paris bureau chief for SpaceNews.