After traveling for 5 years and 400 million miles the million pound Juno spacecraft is almost in position to be placed in orbit around Jupiter.
NASA scientists will attempt to fire rocket engines to put the brakes on the probe and then maneuver it into orbit around the giant gas planet while also turning it back so the solar panels face the sun.
The risky 35-minute operation to move Juno into position is a one shot chance, get it wrong and burn the engines for anything other than the precise 1.2 seconds required and Juno will be sent pinging off into space or sent plunging into the gas clouds and an inevitable crushing
Get it right though and the information we garner from Juno will be invaluable and will help settle the question whether Jupiter has a solid core beneath all those toxic clouds of gas and gain insights on the famous Great Red Spot.
As the distance from Jupiter to the control center is so vast, there is a 48 minute lapse which means that there will be some very nervous technicians and scientists waiting to hear if their 1.2 second calculations were correct or if they have just sent a million pound lump of metal flying towards Alpha Centuri.