It must slow itself to get captured by the gravity of the giant world.
This all-or-nothing job will be performed by its Leros-1b engine built by Moog-ISP in Westcott, Buckinghamshire.
"It`s a tremendous thing for us," said Moog`s chief engineer, Dr Ian Coxhill.
"The engine has to work for Juno to get into orbit; it has to burn at a precise time and burn for a continuous duration of at least 20 mins.
"There`ll be some frayed nerves, for sure."
The Leros-1b was chosen to be the main engine on the Nasa satellite by its manufacturer, Lockheed Martin.
Previous American space agency missions have also used the Westcott technology, including the Messenger probe that went into orbit around Mercury in 2011. So, there is high confidence this latest engine will be up to the task.
Indeed, Juno has already fired it during the epic journey to Jupiter.
Back in 2012, the Leros had to operate reliably twice to refine the trajectory of the spacecraft, and on each occasion the engine burned flawlessly for more than 20 minutes.
"In fact, things went so well that Lockheed Martin said initially they thought they had confused the real flight data on the engine burn with the simulation data. It was that accurate. So that`s obviously really encouraging," Dr Coxhill told BBC News.
The Jupiter Orbit Insertion manoeuvre will be conducted in the early hours of Tuesday morning, British time.
Juno will turn and fire the Leros in the forward direction to try to remove about 500m/s from its velocity - enough so that it goes into a 53-day orbit around the gas giant.
No burn or a burn of insufficient length would send Juno into the oblivion of deep space.
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