WASHINGTON — Spanish satellite operator Hisdesat is trying to retrieve money it paid Kosmotras for a long-overdue Dnepr launch of a radar satellite that Hisdesat has rebooked on a SpaceX Falcon 9 for a flight late this year.

Hisdesat announced last week that it has an agreement with SpaceX to launch PAZ, a 1,400-kilogram synthetic aperture radar satellite from Vandenberg Air Force Base, California, during the fourth quarter.

The satellite was originally supposed to launch on a Dnepr rocket in 2014 under an agreement Hisdesat signed with Kosmotras, a Ukrainian-Russian joint venture that has not launched a Dnepr since 2015 because of difficulties winning Russian government approval for additional launches of the Ukrainian-built rocket.

Hisdesat has sinced turned to the International Court of Arbitration in Paris to recover money it paid Kosmotras for the repeatedly postponed Dnepr. According to Russian news service TASS, Hisdesat is seeking 15 million euros ($16 million).

In a March 10 interview, Hisdesat Chief Operating Officer Miguel Angel Garcia Primo confirmed the legal claim, but declined to say how much Hisdesat is seeking from Kosmotras.

“It is true we are in a procedure to recover the money paid in advance,” he said by email. “The exact figure I would prefer not to comment.”

Kosmotras did not respond to a SpaceNews inquiry.

Hisdesat joins Iridium in pursuing alternatives to Kosmotras for launching satellites. In January, the McLean, Virginia-based fleet operator added an eighth SpaceX mission to the launch campaign for its next generation constellation, Iridium Next, pairing the launch of five Iridium Next satellites with two U.S.-German research satellites. The twin Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellites from NASA and the German Research Centre for Geosciences were also previously booked to launch using Dnepr.

Kosmotras had its last launch in March 2015, orbiting the 1,100 kilogram Kompsat-3A mission for the Korea Aerospace Research Institute. Iridium, which intended to launch the first two Iridium Next satellites on Dnepr, stated that it would still consider launching satellites with Kosmotras if the Russian-government provides the long-delayed approvals.

SpaceX has had its own troubles with launch delays, informing Iridium in February that it was pushing back the launch of its second batch of Iridium Next satellites to mid-June, an eight-week delay. Gwynne Shotwell, SpaceX president and COO, sought to assure customers last week that the launch provider will deliver on its crowded manifest through a combination of increased launcher production, multiple launch sites and the near-term introduction of already-flown first stage boosters.

Hisdesat’s PAZ satellite was built by Airbus Defence and Space to image more than 300,000-square kilometers per day from a 514-kilometer slightly inclined, quasi-polar orbit. According to Hisdesat, PAZ will cover the entire globe with a 24-hour mean revisit time, providing imagery for government and commercial customers. Once launched, PAZ will join the same orbit as Airbus Defence and Space GEO’s TerraSAR-X and TanDEM-X radar satellites that Germany uses.

PAZ is also carrying an Automatic Identification System (AIS) receiver for Canada-based exactEarth, of which Hisdesat is the largest shareholder. Additionally, the satellite supports a weather payload, the Radio Occultation and Heavy Precipitation experiment, for the Spanish National Research Council and the Institute of Space Sciences.