Rocket Lab chief executive Peter Beck said launch costs would be US$4.9 million -- much less than the cost of traditional rocket launches.
Beck said Planet shared his company's vision of seeing space infrastructure enhance how people understood Earth.
San Francisco-based Planet takes high-resolution pictures of Earth every day from its dozens of small satellites.
The startup has more than 100 customers - from agricultural giants like Bayer CropScience to humanitarian organisations - accessing its images and data through a software platform.
When a wildfire erupted in Alberta, Canada, and a 7.8 magnitude earthquake struck Ecuador, Planet released high resolution imagery of the affected regions for free, available under an open usage license, Bloomberg reports.
Planet was founded in 2010 by a team of scientists who worked together at Nasa Ames, a major research center in Silicon Valley and was last year valued at about US$1.1 billion.
Planet joins Nasa, Spire and Moon Express as customers announced to fly on Rocket Lab's Electron launch vehicle.
The company has three Electron rockets on its production line at its base near Auckland Airport.
The company, founded in 2006, has investors including Khosla Ventures, K1W1, Bessemer Venture Partners and Lockheed Martin.
