Juno (spacecraft)

*Juno*
	Artist's rendering of the Juno spacecraft
Names	New Frontiers 2
Mission type	Jupiter orbiter
Operator	NASA / Jet Propulsion Laboratory
COSPAR ID	2011-040A
SATCAT no.	37773
Website	www.nasa.gov/mission_pages/juno/main/index.html (NASA); www.missionjuno.swri.edu (SwRI);
Mission duration	Total: 7 years (planned); 14 years, 221 days (elapsed); ; Cruise: 4 years, 335 days; ; Prime mission: 2 years (planned); 5 years, 16 days; ; Extended mission: 4 years, 236 days (elapsed); ;
Spacecraft properties
Manufacturer	Lockheed Martin Space
Launch mass	3,625 kg (7,992 lb)
Dry mass	1,593 kg (3,512 lb)
Dimensions	20.1 × 4.6 m (66 × 15 ft)
Power	14 kW at Earth, 435 W at Jupiter ; 2 × 60-ampere hour, 28 Volt lithium-ion batteries
Start of mission
Launch date	August 5, 2011, 16:25:00 UTC
Rocket	Atlas V 551 (AV-029)
Launch site	Cape Canaveral, SLC-41
Contractor	United Launch Alliance
Flyby of Earth
Closest approach	October 9, 2013
Distance	559 km (347 mi)
Jupiter orbiter
Orbital insertion	July 5, 2016,; 9 years, 8 months, 9 days ago
Orbits	76 (planned)
Orbital parameters
Perijove altitude	4,200 km (2,600 mi) altitude; 75,600 km (47,000 mi) radius
Apojove altitude	8.1×106 km (5.0×106 mi)
Inclination	90° (polar orbit)
MWR
Instruments
MWR	Microwave Radiometer
JIRAM	Jovian Infrared Auroral Mapper
MAG	Magnetometer
GRAV	Gravity Science
JADE	Jovian Auroral Distributions Experiment
JEDI	Jovian Energetic Particle Detector Instrument
Waves	Radio and Plasma Wave Sensor
UVS	Ultraviolet Imaging Spectrograph
	; Juno mission patch New Frontiers

Juno is a NASA space probe orbiting the planet Jupiter. Built by Lockheed Martin and operated by NASA's Jet Propulsion Laboratory, the spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 UTC, as part of the New Frontiers program. Juno entered a polar orbit of Jupiter on July 5, 2016, UTC, to begin a scientific investigation of the planet. After completing its mission, Juno was originally planned to be intentionally deorbited into Jupiter's atmosphere, but has since been approved to continue orbiting until contact is lost with the spacecraft. The FY2026 budget proposal from the second Trump administration would end the mission, however the continued funding for the mission is still being debated in the United States Congress. If Juno mission receives a third mission extension, it will continue to explore Jupiter for another three years to study Jovian rings and inner moons area which is not well explored; this phase will also include close flybys of the moons Thebe, Amalthea, Adrastea, and Metis.

Juno's mission is to measure Jupiter's composition, gravitational field, magnetic field, and polar magnetosphere. It also searches for clues about how the planet formed, including whether it has a rocky core, the amount of water present within the deep atmosphere, mass distribution, and its deep winds, which can reach speeds up to 620 km/h (390 mph).

Juno is the second spacecraft to orbit Jupiter, after the RTG-powered Galileo orbiter, which orbited from 1995 to 2003. Unlike all earlier spacecraft sent to the outer Solar System and beyond—which used radioisotope thermoelectric generators for power—Juno is powered by solar panels, more commonly used by satellites orbiting Earth and working in the inner Solar System. Accordingly, Juno required the three largest solar panel wings ever deployed on a planetary probe (at the time of launching). These play an integral role in stabilizing the spacecraft as well as generating power.

As of February 2026, Juno remained operational and in contact with Earth through the NASA Deep Space Network.