Jupiter is not just the largest and most massive planet in our solar system. He is a record holder in many respects. Thus, Jupiter has the most powerful magnetic field among the planets, emits in the X-ray range, and has an extremely complex atmosphere. Planetologists are showing great interest in this planet, since it is difficult to overestimate the role of Jupiter in the history of the solar system, as well as in its present and future.
The Juno spacecraft, which reached the giant planet in 2016 and is currently on a research program in orbit around Jupiter, is set to help scientists solve many of its mysteries.
Mission start
Preparation for the expedition of this automatic probe to Jupiter was carried out by NASA as part of the New Frontiers program, focused on the comprehensive study of several objects of the solar system of particular interest. "Juno" became the second mission in the framework of this project. She started 5August 2011 and, having spent almost five years on the road, successfully entered orbit around Jupiter on July 5, 2016.
The name of the station that went to the planet bearing the name of the supreme deity of Roman mythology was chosen not just in honor of the wife of the "king of the gods": it has a certain connotation. According to one of the myths, only Juno could look through the veil of clouds with which Jupiter shrouded his unseemly deeds. Assigning the name of Juno to the spacecraft, the developers thereby identified one of the main goals of the mission.
Probe Tasks
Planetologists have many questions for Jupiter, and the answers to them depend on the fulfillment of the scientific tasks assigned to the automatic station. Depending on the object of study, these tasks can be combined into three main complexes:
- Study of Jupiter's atmosphere. The refined composition, structure, temperature characteristics, dynamics of gas flows in the deep layers of the atmosphere located below the visible clouds - all this is of great interest to scientists, the authors of the Juno scientific program. The spacecraft, justifying the name given to it, looks further with its instruments than has been possible so far.
- Study of the giant's magnetic field and magnetosphere. At a depth of more than 20 thousand km, at colossal pressures and temperatures, huge masses of hydrogen are in the state of liquid metal. The currents in it generate a powerful magnetic field, and knowledge of its features is important for clarifying the structure of the planet and the history of its formation.
- The study of the details of the structure of the gravitational field is also necessary for planetary scientists to build a more accurate model of the structure of Jupiter. It will allow us to more confidently judge the mass and size of the deepest layers of the planet, including its solid inner core.
Juno science equipment
The design of the spacecraft provides for the carrying of a number of instruments designed to solve the above problems. These include:
- Magnetometric complex MAG, composed of two magnetometers and a star tracker.
- Space segment of equipment for gravitational measurements Gravity Science. The second segment is located on the Earth, the measurements themselves are carried out using the Doppler effect.
- MWR microwave radiometer for studying the atmosphere at great depths.
- Ultraviolet spectrograph UVS to study the structure of Jupiter's auroras.
- JADE tool for fixing the distribution of low-energy charged particles in auroras.
- JEDI high-energy ion and electron distribution detector.
- Detector of plasma and radio waves in the magnetosphere of the planet Waves.
- JIRAM infrared camera.
- The JunoCam optical range camera placed on the Juno mainly for demonstration and educational purposes for the general public. This camera has no special tasks of a scientific nature.
Design features and specifications of "Juno"
The spacecraft had a launch mass of 3625 kg. Of these, only about 1600 kg falls on the share of the station itself, the rest of the mass - fuel and oxidizer - are consumed during the mission. In addition to the propulsion engine, the device is equipped with four orientation engine modules. The probe is powered by three 9-meter solar panels. The diameter of the apparatus, excluding their length, is 3.5 meters.
The total power of solar panels in orbit around Jupiter by the end of the mission should be at least 420 watts. In addition, Juno is equipped with two lithium-ion batteries to power it while the station is in Jupiter's shadow.
The developers took into account the special conditions in which Juno will have to work. The characteristics of the spacecraft are adapted to the conditions of a long stay within the powerful radiation belts of a giant planet. The vulnerable electronics of most instruments are placed in a special cubic titanium compartment, protected from radiation. The thickness of its walls is 1 cm.
Unusual "passengers"
The station carries three Lego-style aluminum man figures depicting the ancient Roman gods Jupiter and Juno, as well as the discoverer of the planet's satellites, Galileo Galilei. These "passengers", as the mission staff explains, went to Jupiter in order to attract the attention of the younger generation to science and technology, to interest children in space exploration.
The Great Galileo is on board and in a portrait on a special plaque provided by the Italian Space Agency. It also bears a fragment of a letter written by the scientist in early 1610, where he first mentions the observation of the planet's satellites.
Portraits of Jupiter
The JunoCam, although it does not carry a scientific load, was able to truly glorify the Juno spacecraft to the whole world. Photos of the giant planet, taken with a resolution of up to 25 km per pixel, are amazing. Never before have people seen the magnificent and menacing beauty of Jupiter's clouds in such detail.
Latitudinal cloud belts, hurricanes and whirlwinds of the mighty Jupiterian atmosphere, the gigantic anticyclone of the Great Red Spot - all this was captured by the Juno optical camera. Images of Jupiter from the spacecraft made it possible to see the polar regions of the planet, which are inaccessible for telescopic observations from the Earth and near-Earth orbit.
Some scientific results
The mission has made impressive scientific progress. Here are just a few:
- The asymmetry of Jupiter's gravitational field, caused by the peculiarities of the distribution of atmospheric flows, has been established. It turned out that the depth to which these stripes extend, visible on the disk of Jupiter, reaches 3000 km.
- The complex structure of the atmosphere of the polar regions, characterized by active turbulent processes, has been discovered.
- Measurements of the magnetic field were carried out. It turned out to be an order of magnitude higher than the strongest earthlymagnetic fields of natural origin.
- A three-dimensional map of Jupiter's magnetic field has been built.
- Detailed images of auroras taken.
- New data on the composition and dynamics of the Great Red Spot have been received.
This is not all the achievements of Juno, but scientists hope to get even more information with it, because the mission is still ongoing.
Future of Juno
The mission was originally scheduled to run until February 2018. Then NASA decided to extend the stay of the station near Jupiter until July 2021. During this time, it will continue to collect and send new data to Earth, and will continue to photograph Jupiter.
At the end of the mission, the station will be sent into the atmosphere of the planet, where it will burn. Such an ending is envisaged in order to avoid a fall on any of the large satellites in the future and possible contamination of its surface by terrestrial microorganisms from the Juno. The spacecraft still has a long way to go, and scientists are counting on a rich scientific “harvest” that Juno will bring them.
