The second launch will be a commercial rideshare mission in early 2019.
In addition, Rocket Lab and Spaceflight also signed a letter of agreement, expected to be finalised in the next few weeks, for a third mission that would put a mini satellite from electronics giant Canon into orbit, by the end of next year.
The CE-SAT-I Mark II is an Earth-imaging micro satellite developed by Canon Electronics.
It follows on from the successful launch of Canon Electronics' first experimental CE-SAT-I in 2017. CE-SAT-II is a mass production model equipped with two cameras with different resolutions.
Publicly announced launch customers to-date include Spire, Tyvak Nano-Satellite Systems, Irvine CubeSat Stem Program, NASA, Moon Express and Spaceflight (including their missions for BlackSky and Canon Electronics).
The orbital launch provider Rocket Lab previously confirmed the new launch window for its coming 'It's Business Time' mission, which includes plans to put into orbit a special "drag sail" device, designed by High Performance Space Structure Systems in Germany, to "de-orbit" inactive small satellites, would start from June 23.
The "It's Business Time" launch will include a test of the drag-sail device, which is small, ultra-thin membrane sail that can be stored tightly within a spacecraft and then deployed once the satellite reaches the end of its orbital lifespan.
The reflective panels unfold to 2.5 sq m to increase the spacecraft's surface area, causing it to experience greater drag and pull the satellite back into the Earth's atmosphere, enabling much faster de-orbiting and reducing the amount of space junk in Low Earth Orbit.