Here is how Juno will study Jupiter

Juno launched from Cape Canaveral, Florida on August 5th, 2011 on board an Atlas V-551 rocket and reached Jupiter on July 4th, 2016. Juno’s mission is to study Jupiter by orbiting the planet 32 times during its life passing as close as 5,000 km to the upper-most layers.

As the spacecraft is in a polar orbit around the planet, this is the prime spot for studies into the gravitational and magnetic fields of Jupiter. Juno will precisely map the gravitational field to determine how the mass is distributed throughout the planet as well as properties of its structure. Juno will also map the magnetic field to try and determine its origin and structure as well as how far deep in the planet the field is created.

Another key part of the mission is to determine the ratio of oxygen to hydrogen. In other words, to figure out how much water actually exists in the planet which will hopefully give us insight into how the solar system was formed. Juno will also better estimate Jupiter’s core mass to see how the planet formed in regards to the rest of the solar system.

Mapping every possible element of the cloud layers is also very important; such as mapping the temperature, opacity, composition, structure, and dynamics of the cloud layers at all latitudes. As Jupiter has a strong magnetic field, Juno is going to explore the 3-D structure of the magnetosphere and its accompanying auroras.

The nine instruments that will achieve Juno’s science objectives are; the Microwave Radiometer (MWR), Jovian Infrared Auroral Mapper (JIRAM), Magnetometer (MAG), Gravity Science (GS), Jovian Auroral Distributions Experiment (JADE), Jovian Energetic Particle Detector Instrument (JEDI), Radio and Plasma Wave Sensor (Waves), Ultraviolet Imaging Spectrograph (UVS), and JunoCam (JCM). 

The MWR has six antennas that will each pick up a certain wavelength in the microwave range; 600 MHz, 1.2 GHz, 2.4 GHz, 4.8 GHz, 9.6 GHz, and 22 GHz. These wavelengths correspond to the only microwaves that can escape Jupiter’s thick atmosphere. The radiometer will me measuring the amount of ammonia and water in the deeper layers of the Jovian atmosphere at about 500 to 600 km. Combining the data from both of these devices, it is possible to get a temperature profile at different depths.

The JIRAM will conduct its studies to the upper layers at around 50 to 70 km deep. It will provide images of the aurora as well as see how the water and clouds are moving beneath the upper layers. JIRAM can also detect other important molecules like water vapor, methane, and phosphine.

There are two parts to the magnetometer, the Flux Gate Magnetometer (FGM) and the Advanced Stellar Compass (ASC). The FGM measures the strength and direction of the magnetic field lines while the ASC monitors the orientation of the FGM sensor. The magnetometer has a very important job as its data will be used to help map the magnetic field around Jupiter, reveal clues to the dynamics of the planet’s interior, and make a 3-D structure of the polar magnetosphere.

The purpose of the GS is to study and map the distribution of mass inside the planet by using small variations in gravity in Jupiter’s orbit.

JADE’s mission is to measure the energy and velocity vector of the low energy ions and electrons in Jupiter’s aurora.

While JEDI’s mission is to measure the energy and velocity vector of the high energy ions and electrons in the polar magnetosphere.

The Waves instrument will be surveying the plasma and radio spectra in the auroras to look at the acceleration of the particles in the aurora.

As the spacecraft is spinning, the UVS will be recording the wavelength and arrival time of the ultraviolet photons that pass through the instrument’s slit as it turns toward and away from the planet. It will also provide ultraviolet images of the auroras.

The final instrument aboard Juno is the JunoCam. This instrument is purely educational and designed for public outreach. JunoCam will only function for about seven orbits around the planet as the harsh radiation field’s of Jupiter will slowly destroy it. It will take the first post-orbit photo around August 27th.