A national security mission for the National Reconnaissance Office is expected to be launched from Rocket Lab's launch site in New Zealand.

This is the second of two back-to-back missions for the NRO from a spaceport outside of the United States.

If it is dark and the sky is clear when the rocket is launched, it will be possible to see the rocket from BOP, says Dave Greig at Tauranga Astronomical Society.

Tonight's launch window is from 5pm to 7pm.

The mission, dubbed Antipodean Adventure (NROL-199), is the second of two back-to-back Electron missions for the National Reconnaissance Office, says Rocket Lab in a post on its website.

The first mission, Wise One Looks Ahead (NROL-162) successfully lifted-off from Launch Complex 1 on July 13, 2022.

'The NROL-199 mission will carry a national security payload designed, built, and operated by the National Reconnaissance Office in partnership with the Australian Department of Defence as part of a broad range of cooperative satellite activities with Australia,” the website post reads.

'The payload will support the NRO to provide critical information to government agencies and decision makers monitoring international issues.

'Both NROL-199 and NROL-162 missions are a demonstration of responsive launch under NRO's Rapid Acquisition of a Small Rocket (RASR) contract for launching small satellite through a streamlined, commercial approach, and are the third and fourth missions contracted to Rocket Lab by the NRO under the contract.

'NROL-151 (RASR-1) was successfully deployed to space on a dedicated Electron launch in early 2020, followed by RASR-2 on another Electron launch in June 2020.”

The launch can be viewed on the livestream above from 5pm.