Juno space probe arrives at Jupiter

NASA’s Juno spacecraft was successfully launched into orbit around Jupiter on the morning of July 5. At 4:53 a.m. Central European Time, NASA received a confirmation signal that the spacecraft had slowed down in time and is now in orbit around the gas giant.

The spacecraft arrived at the north pole of Jupiter and had to make a spin there using the main rocket. Juno also had to slow down to the speed that would allow him to enter Jupiter’s orbit; in total, the probe had to reduce its speed by 542 meters per second or 1951.2 km/h. To do this, the rocket had to be able to brake between 20 and 35 minutes, something for which NASA put all communications and systems on standby to minimize the chance of errors.

It takes about 48 minutes to send a signal to Juno and another 48 minutes to get a signal back. It was therefore not possible to control the space probe in the event of a possible failure of, for example, the rocket. After Juno orbited Jupiter, the probe turned toward the sun to allow the 18,689 solar cells to collect energy again, NASA writes.

Juno’s main mission is to increase knowledge about Jupiter and understand how that planet evolved. Juno will study origin, internal structure, deep atmosphere and magnetosphere. For example, humanity must learn more about the presence or absence of a solid core of the planet, about the powerful magnetic field, the amount of water and ammonia in the atmosphere and the auras of the planet. The knowledge should contribute to the understanding of ‘our’ solar system and how systems with planets form.

Before the probe really starts collecting data on Jupiter, several tests of the systems are being conducted. The official start of data collection is not until October, but NASA’s scientists suspect they can start collecting data earlier.

NASA named Juno after the Roman goddess of the same name. She was the wife of Jupiter in Roman mythology. The space probe itself is 3.5 by 3.5 meters with three solar panels measuring 9 by 2.65 meters, giving a total solar panel surface area of ​​60 square meters. The latter is also special: it is the first spacecraft that is so far from the sun with solar panels as an energy supplier. The large amount of solar cells provides about 14 kilowatts near Earth, while it is only 500 watts near Jupiter.

When launched from Earth, the device weighed 3625 kilograms, of which 1280 kilograms consisted of fuel in the form of hydrazine and 752 kilograms of oxidizer. After slowing down in Jupiter’s atmosphere, that will be about halved.

Juno carries 29 different sensors that transmit data to nine instruments on board. The JunoCam has a field of view of 58 degrees and a resolution of 1600×4800 pixels for color photos. The camera also has a filter with which the spectrum of methane can be photographed. Then the resolution is halved.

Because the spacecraft orbits around its own axis twice a minute, the camera is equipped with software that makes photos look uneven. The pictures are taken at the same speed as the probe spins in circles. In addition, there are nine scientific instruments on board, including those for measuring gravity, spectrometers, wave meters and special cameras for UV and infrared radiation. And there are three Lego figures in the shape of Jupiter, Juno and Galileo Galilei.

Eventually, Jupiter Juno’s gravitational pull will become too strong and she will crash into Jupiter on February 20, 2018 after traveling 2800 million kilometers and 560 million kilometers of orbits around Jupiter, without crashing. The reason for the controlled crash of Juno is to prevent the spacecraft from colliding with one of Jupiter’s moons. That has to do with not wanting to pollute the moons with the toxic propellants.

Another reason for not wanting to crash into one of the moons is that extremophiles, certain bacteria that can survive under extreme conditions, may have been able to travel with the probe. Those extremophiles could be harmful to any existing life. NASA has a protocol for this through the NASA office of planetary protection.

If all goes well, Juno will have covered some 3390 million kilometers by the end of its journey, including its engulfment by Jupiter.