North Korea appears to have conducted a rocket engine test in recent days, according to NK Pro analysis of satellite imagery, after Russian leader Vladimir Putin signed a new agreement on space program cooperation with Kim Jong Un.

The apparent test at the Sohae Satellite Launching Grounds vertical engine test stand follows the DPRK’s failed attempt to put a second military reconnaissance satellite into orbit on May 27, indicating preparations are underway for another attempt soon.

Planet Labs and Sentinel-2 satellite imagery suggests an engine test took place at the vertical stand between June 21 and