Curveball

The Curveball mission was conducted as part of a U.S. military test program. No official information has been released regarding the payload's objectives or flight profile. The available orbital data suggest that Curveball was inserted into a very low orbit before rapidly ending its mission.

The launch vehicle was Rocket Lab's HASTE configuration, a modified version of the Electron small satellite launcher adapted for hypersonic technology testing. HASTE retains Electron's two-stage architecture with a modified kick stage but is normally employed for high-speed suborbital trajectories rather than orbital missions.

The U.S. Space Force cataloged the Electron second stage in a 189 × 204 km, 40.0° inclination orbit and the kick stage in a 198 × 199 km, 40.0° inclination orbit. No orbital elements were released beyond these approximate parameters. The orbit is consistent with the 40–41° inclination implied by pre-launch hazard areas in the western Atlantic. Both rocket stages were expected to reenter the atmosphere within approximately two days of launch.

The payload itself was not cataloged. The most likely explanation is that Curveball separated into a low Earth orbit and immediately used onboard propulsion to perform a controlled deorbit into the Atlantic Ocean before completing one revolution, preventing its inclusion in the public satellite catalog. An alternative possibility is that the vehicle completed most of a single orbit before executing a guided reentry to a recovery area in the western United States, such as the Utah Test and Training Range. No official confirmation of either scenario has been released.