A spacecraft on a mission to Jupiter will make a record-breaking close approach to the huge planet on Saturday.
Juno will have all nine of its instruments activated as it flies 2,500 miles above Jupiter's swirling cloud tops at 130,000 miles per hour.
The probe has already sent back a photo of the planet, but mission controllers at Nasa expect it to capture more detailed images and a wealth of data about the planet from the close approach.
Principal investigator Dr Scott Bolton, from the Southwest Research Institute in San Antonio, Texas, said: "This is the first time we will be close to Jupiter since we entered orbit on July 4. Back then we turned all our instruments off to focus on the rocket burn to get Juno into orbit around Jupiter.
"Since then, we have checked Juno from stem to stern and back again. We still have more testing to do, but we are confident that everything is working great, so for this upcoming flyby Juno's eyes and ears, our science instruments, will all be open.
"This is our first opportunity to really take a close-up look at the king of our solar system and begin to figure out how he works."
It will take some days for the data and images gathered by Juno to be downloaded on Earth.
Nasa hopes to release a handful of close-up images form JunoCam, the probe's panoramic colour camera, late next week, and they should include the first detailed photographs of Jupiter's north and south pole.
No previous spacecraft has flown so near to Jupiter - the current record for a close approach to the planet was set by Nasa's pioneer 11 spacecraft, which passed some 27,000 miles out in 1974.
Juno is part of Nasa's New Frontiers programme of robotic space missions, but unusually for such a mission, the probe is carrying passengers - three Lego figures depicting the 17th century Italian astronomer Galileo Galilei, the Roman God Jupiter, and his wife Juno.
The Lego figures have been made out of aluminium rather than plastic, so they could withstand the extreme conditions of the flight.