Minor changes have been made to Rocket Lab's Electron rocket for a new attempt to put New Zealand into space.
An attempt last year failed to get the rocket, known as Still Testing, to take off - so it's giving it another go today.
Rocket Lab boss Peter Beck says major tweaks were unnecessary.
"The reason we didn't reach orbit on flight one was nothing to do with the vehicle - it was to do with a third-party contractor on the ground."
If weather prevents a take-off attempt today, Rocket Lab has eight more days in the test window to get it off the ground.
Unless the weather is perfect, no launch will be attempted.
"It's a giant experiment, and with any experiment you need to make sure your initial conditions are perfect. In our case, that's the weather."
Saturday's launch window is between 2:30pm and 6:30pm. The attempt will be livestreamed on Rocket Lab's YouTube page.
The rocket will be carrying three customer satellites - two for mapping ships and weather, the third from a satellite imaging company.
"In doing so we'll become the second company in the world to have put something in orbit, and New Zealand the 11th nation."
Last year's test failed when the third stage of the rocket failed to reach its 500km target altitude.