Rocket Lab: Hoping for better weather and no International Space Station today

Road closures are in place on Mahia Peninsula as Rocket Lab hopes it will be fifth day lucky with its launch attempt.

Weather today is fine following the scrub yesterday due to deteriorating conditions and the proximity of the orbiting 450-tonne International Space Station (ISS). Bad weather also prevented launch over the weekend.

The 108m wide station orbits at about 400km above Earth, around the same altitude Rocket Lab wants to reach to deploy small satellites.

A spokeswoman today said the ISS was another factor that played into when Electron could launch.

''Within our launch windows there are certain times we can't launch as we wait for satellites and spacecraft (such as the ISS) to pass. As a result, our launch window gets broken into several smaller windows where there is a clear path to orbit,'' she said.

''We had several of these clear windows yesterday and we are aware of when these will be well in advance of a launch attempt. However, as the weather began to close in it overlaid some of these clear windows, leaving us just a narrow six-minute window that was both clear of ISS movements and weather.''

For that reason, Rocket Lab chose to hold off until today.

While preparations are underway for a launch from 2.30pm-on it could, however, be scrubbed within seconds of the scheduled liftoff for technical reasons or because of a shift in weather conditions.

Rocket Lab says it will issue more updates and livestream details throughout the day. The launch will be available through nzherald.co.nz.

In May, the New Zealand-founded company successfully reached space in a global first from a private launch facility.

A communications glitch meant the flight had to be terminated before reaching orbit but Rocket Lab founder and chief executive Peter Beck has said while thrilled with the first launch, the company has learned from thousands of pieces of data.

The 17m-tall Electron orbital launch vehicle will carry two Earth-imaging Dove satellites for Planet and two Lemur-2 satellites from Spire for weather mapping and ship traffic tracking.

If needed the company will launch a third test flight but it is keen to accelerate its transition into full commercial operations.