It was originally hoped the launch could take place before Christmas but due to technical and regulatory issues it had to be pushed into 2023.
On Thursday, Virgin Orbit's LauncherOne system successfully completed an end-to-end launch rehearsal.
Dan Hart, Virgin Orbit chief executive, said: "After ensuring that every technical aspect is sound and every regulation and code has been satisfied, it is gratifying to see this historic endeavour on the verge of coming to fruition.
"This launch represents the opening of a new era in the British space industry and new partnerships across industry, government, and allies."
Melissa Thorpe, head of Spaceport Cornwall, said: "This is a phenomenal moment with incredible international collaboration. Virgin Orbit, the UK Space Agency and all of our partners are breaking new ground to transform access to space across the world from right here in Cornwall.
"My team at Spaceport Cornwall have worked so hard to get this far and we wish everyone the best of luck as the launch window opens, we are ready."
