Rocket Lab is confident it has done the ground work for a successful launch but will wait for the right conditions and could scrub it within a split second of lift-off.
Long-range weather forecasts are favourable for a launch from Rocket Lab's pad at Mahia at the start of next week.
The company wants to send a test rocket into orbit during a 10-day window from next Monday but warns that unfavourable weather could result in the launch being scrubbed.
MetService forecasts for next Monday say it will be partly cloudy with little wind in the area. Victoria University forecast data also shows little wind on the Mahia Peninsula, between Gisborne and Napier.
The nearest town to the site is Wairoa.
Rocket Lab founder and chief executive Peter Beck said winds in the upper atmosphere were more critical.
Technical issues could also result in a postponement but there had been painstaking ground testing over the last few years and the 17m-tall Electron rocket on site was ready.
The company had hoped to launch last year but it has been hit by delays, including a false start with a launch site on Banks Peninsula which it pulled out of.
Beck said today the Auckland and Mahia-based team were feeling great.
"There are no technical issues and will give it a good shot. Very few space missions made it from the planning phase to the launch pad.
"We're going into this launch with a high degree of confidence. We've done more testing than most to simulate what will happen but its hard to simulate many times the speed of sound," he said.
"Sometimes you have to learn on the way up."
Beck said the real celebrations wouldn't start until the Rocket Lab programme had reached a commercial phase of frequent, low-cost launches. It plans for three test launches before taking commercial cargo - small satellites - into orbit.
"There will be some champagne flowing (following a successful test) but it's the commercial phase when it will be really great."
Beck said for the test launch he would be in Mission Control at the company's Auckland base for the launch.
There would be 25 controllers monitoring 20,000 different channels of data. Each system, including propulsion, stages of the rocket and guidance had to be functioning perfectly or "green" for the launch to go ahead.
US Federal Aviation Administration officials will be at the control centre too for the launch which has required new laws and the establishment of a space agency within the Ministry of Business, Innovation and Employment.
Each launch is expected to cost around US$4.9 million (NZ7.1m). Lockheed has reportedly estimated the average cost of a space rocket launch at around US$225m.
Beck, who has worked on the project for more than a decade, is not pushing a remote ignition switch. Once the order to commence autosequence is given, the on-board systems will initiate launch.
The rocket has a "kill switch" which can be activated at any time following ignition as a result of a malfunction. A termination can be manually or automatically executed which cuts all power to the Rutherford engines which burn a mix of liquid oxygen and kerosene.
Rocket Lab has released a detailed rundown of what will happen in the countdown to a launch:
What happens on launch day?
• Seven hours before launch: Emergency crews, local officials and Rocket Lab team gather for a briefing and move into position for launch
•-06:00:00 Road to the launch site closed
•-04:00:00 Electron lifted to vertical position and filled with fuel
•-02:30:00 Launch pad personnel exit area in preparation for launch
•-02:00:00 Electron filled with liquid oxygen (LOx)
•-01:00:00 Aviation authority advised to alert aircraft pilots of potential hazards
•-00:10:00 Final preparations for launch commence
•-00:02:00 Autosequence commences and the Electron's on-board computers initiate the launch sequence
•-00:00:02 Ignition of the nine Rutherford engines powering Electron's first stage
• 00:00:00 Lift-off - Electron climbs from the launch pad - initially rising slowly and increasing in speed as the Electron gets lighter
•+00:02.30 Engines powering Stage 1 cut off
•+00:02.34 Stage 1 of Electron separates
•+00:02.36 The vacuum Rutherford engine on Stage 2 ignites
•+00:03.07 The Electron's fairing (the protective casing around the payload) separates
•+00:07.24 Stage 2 engine cuts off
•+00:07.26 Electron reaches its final orbit
•+00:07.31 Payload separates from the launch vehicle
•+00:07.32 Electron completes flight
What exclusion zone will be in place?
A safety exclusion zone will apply around the launch site shortly before, during and after the flight. The exclusion zone applies to all unauthorised
pedestrians, vehicles and vessels.
How big is the exclusion zone?
Information on exclusion zones will be at www.rocketlab.co.nz/mahia and on signs at Mahia boat ramps.
Will locals be affected by noise levels?
Peak sounds will be very brief, with the highest sound levels only sustaining for less than 30 seconds. The highest predicted sound level for any house outside the exclusion zone, on the peninsula, will be roughly the same as the sound of a vacuum cleaner. The peak sound in Mahia Township will be similar to the level of a conversation in a quiet office.
How close can I get to the launch site?
As Rocket Lab's top priority is safety, safety zones will be in effect during the launch and no access will be permitted to Onenui Station. A security cordon will be in place on Mahia East Coast Rd.
How long after a scrub will the next launch attempt be?
A decision will be made as soon as possible after a scrub as to when the next launch attempt will occur. This decision will be based on a variety of
factors but a follow up attempt could be as early as the following day.
Will a viewing platform be provided?
Launch Complex 1 is not visible during the test launch from any publicly accessible point on the Mahia Peninsula. Wairoa District Council is evaluating the location of possible viewing areas but these will not be in place for the test phase.
Who owns Rocket Lab?
Rocket Lab is a privately funded company with its major investors including Sir Stephen Tindall's K1W1 and US firms Khosla Ventures, Bessemer Venture Partners and Lockheed. The company has developed and launched a number of smaller rockets and received up to $25 million of New Zealand government funding over five years. It has its corporate headquarters in Los Angeles but a research and manufacturing base near Auckland Airport and its launch pad at Mahia.
Who is Peter Beck?
Grew up in Invercargill in a family of engineers. Worked at Fisher & Paykel and developed a passion for space travel. He set up Rocket Lab in 2006. In 2015, he was named New Zealander of the Year for Innovation.