Jupiter emits strong radio waves in both intermittent bursts and steady streams with variable frequencies, likely coming from charged particles present within its intense radiation belts.
NASA’s Galileo mission orbited Jupiter, while Ulysses passed through its magnetosphere on its journey towards Saturn. Juno will provide researchers with vital data regarding Europa and Ganymede where liquid water may exist beneath their rocky seafloors.
Galileo
Galileo Galilei studied Jupiter and its four major moons during this spacecraft’s mission. Its descent probe dove into its gaseous core to collect data on pressure, temperature and winds before transmitting this information back home.
The spacecraft’s instruments measured the composition of gases and surface minerals on Europa, Ganymede and Callisto as well as scanning their magnetospheres.
A global network of sensor stations monitors satellites and their signals for any errors caused by orbital motion, clock drift and atmospheric interference, with any necessary corrections being uplinked back to them and integrated into their navigation signals.
Juno
Juno will explore Jupiter’s atmosphere to unprecedented depth, uncovering its structure, movement and chemical composition down to 1,000 atmospheric pressure units (550 miles or 800 kilometers below its cloud tops). Furthermore, Juno’s Microwave Radiometer will help determine if there is water present in its clouds.
Juno had already discovered that Jupiter’s giant cyclonic storms at its poles are organized polygonally: eight cyclones form an octagonal pattern in the north and five form pentagonal patterns in the south. Although these storms attempt to move poleward, other cyclones at each pole block their progress by pushing back.
Pioneer 10
Pioneer 10 and 11 spacecraft were the first to traverse the asteroid belt and visit Jupiter and Saturn. Their flight illuminated our solar system’s outer limits while creating a trail for later Voyager probes to follow.
Pioneer 10 utilized its Helium Vector Magnetometer to map out Jupiter and its satellites’ magnetic fields, while other instruments measured particles emitted by the sun and cosmic rays.
In 1974, a probe spotted Jupiter’s Great Red Spot — an anticyclonic storm of vast proportions far bigger than Earth — which had existed for centuries. Over time, the probe moved closer and closer toward Jupiter until finally coming within three times its radius — close enough that no instruments on board would be damaged by Jupiter’s radiation environment.
Pioneer 11
The Pioneers studied Jupiter and Saturn’s atmospheres, magnetic fields, rings, moons and interplanetary dust environments as well as gathering data about their internal structures and composition. Instruments also collected information on density measurements of both planets as well as information regarding internal composition.
At its close encounter with Jupiter in December 1973, Voyager 1 captured incredible images of its Great Red Spot as well as observing its polar regions for the first time and measuring Callisto, Jupiter’s largest moon.
Pioneer 11 carried, like Voyagers before it, a plaque featuring Earth and offering greetings to any life that might discover it from beyond Earth’s boundaries. It was designed by Don Bane and Richard Hoagland at JPL who sought help from Dr Carl Sagan at JPL for this endeavor.
Voyager 1
The Voyager spacecraft, launched to explore Jupiter, Saturn and Uranus with their moons in 1979-1989 respectively, revolutionised our understanding of outer planets. They discovered active volcanism on Jupiter’s moon Io and saw the Great Red Spot as an intricate storm made up of counter-rotating eddies.
They carried an extraterrestrial message on 12-inch gold-plated copper discs, in the form of images, music and greetings in 55 languages as well as a map of our solar system with references to 14 pulsars that could help locate Earth.
Voyager 2
Voyager 1 and Voyager 2, launched by NASA from Cape Canaveral Air Force Station in Florida on August 20, 1977 and September 5 respectively, were the first spacecraft to explore our solar system’s outer planets in full.
The probes took advantage of an unusual cosmic alignment that occurs only every 176 years, which allowed spacecraft to safely traverse Jupiter, Saturn, Uranus and Neptune without large onboard propulsion systems or need for gravity assists from each flyby – giving gravity boosts while curving their trajectory – shortening flight time to Neptune from 30 years to 12 years.
New Horizons
New Horizons made close observations of Jupiter and its four largest moons during a slingshot flyby in 2007. One highlight was capturing time-lapse video of Io’s volcanic eruption – the first such footage outside Earth!
This Voyager probe is intentionally compact and only contains a fraction of the instrumentation of previous missions, in order to fit its payload within a spacecraft weighing as little as a piano. APL engineers borrowed science instrument designs from institutions like Southwest Research Institute.