The mission failure comes shortly before the Kiwi-American company's US$4.1 billion ($6b) Nasdaq listing, due to take place by the end of June, with more than 3000 Kiwi investors already onboard, and ahead of its mission later this year to ferry a Nasa satellite into lunar orbit.
The rocket was carrying two Earth-observation satellites for BlackSky, an Earth-imaging company with civilian, intelligence community and defence customers.
It was Rocket Lab's third failure in 20 launches of its Electron rocket. Its very first launch in 2017 - a test mission - was purposefully destroyed after a suspected problem with downrange tracking, which turned out not to be an issue.
In 2020 it lost a rocket to what turned out to be an electrical wiring fault, introduced during manufacture.
"Today's anomaly occurred after 17 successful orbital launches of the Electron launch vehicle. With multiple launch vehicles currently in production, Rocket Lab is prepared for a rapid return to flight as soon as investigations are complete and any required corrective actions are in place," the statement said.
Rocket Lab said the rocket's first stage successfully parachuted into the ocean and crews were working to recover it. The company is trying to develop a capability to recover and reuse Electron first stages.
It is also working with the Federal Aviation Administration (FAA) to investigate the anomaly and identify the root cause to correct the issue for future missions.
"We are deeply sorry to our customer BlackSky for the loss of their payloads. We understand the monumental effort that goes into every spacecraft and we feel their loss and disappointment. Our team is working hard to identify the issue, rectify it, and be safely back on the pad as soon as possible," Rocket Lab founder and chief executive Peter Beck said.
"On one of our toughest days, our team operated with professionalism and worked swiftly to ensure the anomaly was managed safely. Our team is resilient, and our top priority remains to safely and reliably return to flight for our customers. We will learn from this, and we'll be back on the pad again."
On a conference call last week, Beck described 2021 as a huge year for his company.
Beyond its Nasdaq listing and Nasa lunar mission, it has the first flight (for the US Air Force) scheduled from its new launchpad in Virginia, and has started work on its new, much larger Neutron rocket, slated for its first flight in 2024. The Neutron will be cable of taking crew and an 8000kg payload into orbit.
Saturday's launch was also supposed to be its second rocket-retrieval system, and the first of its new "Orca" retrieval cradle.
On Friday, the Herald revealed that at least 3000 New Zealanders are already onboard for Rocket Lab's Nasdaq debut, via buying shares in Vector Acquisition - the "blank cheque" or special purpose acquisition company (spac) that will be the vehicle for its US listing.