Advanced science.  Applied technology.


Juno spacecraft to arrive at Jupiter, enter orbit July 4

For immediate release

San Antonio — June 13, 2016 — In less than one month, NASA’s Juno spacecraft will arrive at Jupiter, the largest planet in our solar system, to begin a 20-month science mission. The spacecraft will enter a polar orbit to answer some fundamental questions about the gas giant and, in turn, about the processes that led to the formation of our solar system.

“When Juno arrives at Jupiter, it will be the fastest human-made object in history,” said Dr. Scott Bolton, associate vice president of the Space Science and Engineering Division at Southwest Research Institute® (SwRI®), who is the Juno principal investigator. “As we approach the gas giant, we will fire Juno’s motor to slow down and be captured into Jupiter orbit. Once we get into orbit, the fun begins. We start looking with all of our ‘eyes and ears.’”

The Juno science team will unmask the mysteries that lie beneath the swirling clouds on Jupiter’s visible facade, to address such questions as: Does Jupiter have a solid core? How deep into the atmosphere do the Great Red Spot and other atmospheric features reach? How much water does Jupiter contain? Juno also will take advantage of its polar orbit to investigate Jupiter’s powerful aurora.

Juno launched Aug. 5, 2011, and swung back by Earth in 2013 for a gravity-assisted boost. Over the course of the mission, Juno will orbit the planet 33 times, collecting science data. With a suite of nine instruments, scientists will look at the internal composition of Jupiter to determine how deep the colorful surface features persist, mapping the atmosphere’s composition, temperature, clouds, and patterns of movement to unprecedented depths. Measuring water and ammonia levels, as well as Jupiter’s gravity fields, will help us understand what’s at the gas giant’s core and how Jupiter and the rest of the planets in our solar system formed.

“The history of volatiles including oxygen across our solar system is very important to the formation of the Earth and life itself,” said Bolton. “We don’t know where the elements that formed us came from. Since Jupiter likely formed first and took most of the leftovers after the Sun formed, discovering how it was formed will reveal a key piece of our solar system’s history.”

Scientists are looking for evidence of pressurized hydrogen that is believed to generate Jupiter’s massive magnetic field, creating a powerful magnetosphere that sparks the brightest aurora in our solar system. Juno will directly sample the charged particles and magnetic fields and simultaneously observe these massive bursts of energy emitting from the poles to better understand these phenomena.

SwRI also built two science instruments for the mission. The Jovian Auroral Distributions Experiment (JADE) will measure the auroral electron and ion populations along the planet’s magnetic field lines and determine which particle populations create the Jovian aurora.

“With JADE, we’re trying to understand what’s the same, and what’s different, between the auroras at Earth and Jupiter so we can understand the processes that create them in detail for the first time,” said SwRI’s Dr. Phil Valek, who serves as lead co-investigator of the instrument. “We’ll be really successful when we can tell the world how it really works, what particles are involved, and why.”

The second instrument, the Juno Ultraviolet Spectrograph (UVS), will image ultraviolet emissions from the Jovian aurora, allowing space scientists to correlate auroral observations with JADE observations of the particle populations that create them.

“Juno’s UVS will provide Hubble-like images of Jupiter’s powerful and dynamic aurora, but from much better vantage points directly above the north and south poles,” said SwRI’s Dr. Randy Gladstone, who serves as the UVS lead co-investigator.

Juno, named for the mythological wife of the god Jupiter who used her special powers to discover the secrets Jupiter was hiding behind cloud cover, will probe the mysteries beneath Jupiter’s surface to understand its structure and history. Jupiter’s giant mass has preserved its original composition, perhaps providing a “Rosetta Stone” to explain more about the rest of the solar system as well.

Juno is the second mission designed under NASA’s New Frontiers Program. The first was the SwRI-led New Horizons mission, which provided the first historic look at Pluto and its moons during the July 2015 flyby and is now on its way deep into the Kuiper Belt. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the Juno mission for the principal investigator. Lockheed Martin of Denver built the spacecraft. The Italian Space Agency contributed an infrared spectrometer instrument and a portion of the radio science experiment.

For more information about the Juno mission, visit

For more information, contact Deb Schmid, (210) 522-2254, or Robert Crowe, (210) 522-4610, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.