Juno captured this view of the Jovian system on June 24, as it approached.
NASA
In the early 2000s, scientists began planning to design and build a spacecraft that could not only survive the journey to Jupiter, but also remain in its hellish radiation environment long enough to explore the gas giant’s composition and mysterious interior. to study carefully. For the spacecraft, the radiation dose during the 1.5-year science mission is equivalent to a patient sitting in a dentist’s chair and being x-rayed every second of every day for three years.
Juno is now more than 850 million kilometers from Earth. After all that work, a spectacular launch and a space cruise, Juno’s fate comes down to tonight: Can it successfully orbit the solar system giant?
Engineers at NASA’s Jet Propulsion Laboratory in California have already sent a command to the spacecraft to start autopilot mode. This was the beginning of a software program that will culminate Monday night when the spacecraft’s main engine, a Leros 1b built by Moog-ISP in England, fires for 35 minutes. That burn starts at 11:18 pm ET (4:18 am BST on July 5).
The Juno spacecraft, named after the Roman goddess who was both the sister and wife of Jupiter, weighs about 3,600 kg and is 3.5 meters long and 3.5 meters wide. It features huge solar panels totaling 60 square meters, as the solar energy on Jupiter is about 25 times weaker than on Earth. In addition to understanding the planet’s mysterious interior, scientists also hope to collect data that will allow them to piece together Jupiter’s formation and evolution as the largest planet in the solar system and understand the precise mechanism that generates its large magnetic field.
The spacecraft carries eight instruments in a vault with a thick titanium case to protect them from the harsh Jovian environment. Also included is a camera, JunoCam, but that tool is more for public outreach than science. While it will provide some stunning images of Jupiter, especially its poles, the mission’s primary goal is to examine the planet in unseen wavelengths of light, as well as measure its gravity distribution. The science instruments will likely activate late Wednesday or early Thursday, assuming all goes well tonight.