The launch window, originally slated for April 20 to May 3, 2018, was moved after unusual behaviour was identified in a motor controller during a wet dress rehearsal.
The cause of the issue was found and corrective measures put in place.
New customers were added to the original launch manifest, including IRVINE01, an educational payload from the Irvine CubeSat STEM Program (ICSP), and NABEO, a drag sail technology demonstrator designed and built by High Performance Space Structure Systems GmBH.
The new payloads join existing customers, two Lemur-2 satellites from Spire Global and a GeoOptics Inc. satellite by Tyvak NanoSatellite Systems.
The payloads will be launched to a 500km x 250km elliptical orbit at 85 degrees, before being circularised using Rocket Lab's Curie engine powered kick stage.
The Electron rocket has had two successful test flights, one in May last year, and the other in January 2018.