Juno (spacecraft)
Encyclopedia
Juno is a NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 New Frontiers
New Frontiers program
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of researching several of the Sun's planets including Jupiter, Venus, and the dwarf planet Pluto...

 mission to the planet Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

. Juno was launched from Cape Canaveral Air Force Station on August 5, 2011. The spacecraft is to be placed in a polar orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...

 to study the planet's composition, gravity field, magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

, and polar magnetosphere
Jupiter's magnetosphere
The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary...

. Juno will also search for clues about how Jupiter formed, including whether the planet has a rocky core, the amount of water present within the deep atmosphere, and how the planet's mass is distributed. It will also study Jupiter's deep winds, which can reach speeds of 600 kilometres per hour (372.8 mph).

The spacecraft's name comes from Greco-Roman mythology. The god Jupiter
Jupiter (mythology)
In ancient Roman religion and myth, Jupiter or Jove is the king of the gods, and the god of the sky and thunder. He is the equivalent of Zeus in the Greek pantheon....

 drew a veil of clouds around himself to hide his mischief, but his wife, the goddess Juno
Juno (mythology)
Juno is an ancient Roman goddess, the protector and special counselor of the state. She is a daughter of Saturn and sister of the chief god Jupiter and the mother of Mars and Vulcan. Juno also looked after the women of Rome. Her Greek equivalent is Hera...

, was able to peer through the clouds and see Jupiter's true nature.

Mission summary

Juno requires a five-year cruise to Jupiter, arriving around July 4, 2016. The spacecraft will travel roughly over a total distance of 1,740 million miles (2,800 million kilometers). The spacecraft will orbit Jupiter 33 times during one Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 year. Junos trajectory will use a gravity assist speed boost from Earth, accomplished through an Earth flyby
Flyby
Flyby may refer to:* Flypast or flyover, a celebratory display or ceremonial flight* Planetary flyby, a type of interplanetary spacecraft mission* Gravity assist, a spaceflight maneuver* "Fly by II", a single released by the UK band Blue...

 two years (October 2013) after its August 5, 2011 launch. In 2016, the spacecraft will perform an orbit insertion burn to slow the spacecraft enough to allow capture into an 11-day polar orbit.
Once Juno enters into its orbit, infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 and microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 instruments will begin to measure the thermal radiation emanating from deep within Jupiter's atmosphere
Atmosphere of Jupiter
The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide and water. Although water is...

. These observations will complement previous studies of the planet's composition by assessing the abundance and distribution of water, and therefore oxygen. While filling missing pieces of the puzzle of Jupiter's composition, these data will also provide insight into the planet's origins. Juno will also investigate the convection that drives general circulation patterns in Jupiter's atmosphere. Meanwhile, other instruments aboard Juno will gather data about the planet's gravitational field and polar magnetosphere. The Juno mission is set to conclude in October 2017, after completing 33 orbits around Jupiter, when the probe will be de-orbited to crash into Jupiter.

Team

Scott Bolton
Scott Bolton (engineer)
Dr. Scott Bolton is Director of the Southwest Research Institute's Space Science and Engineering Division. He is currently the principal investigator for Juno, a mission to study Jupiter's magnetic and gravitational fields, part of NASA's New Frontiers program to explore the outer planets of the...

 of the Southwest Research Institute
Southwest Research Institute
Southwest Research Institute , headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States...

 in San Antonio, Texas is the principal investigator and is responsible for all aspects of the mission. The Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 in California manages the mission and Lockheed Martin Corporation is responsible for the spacecraft development and construction. The mission is being carried out with the participation of several institutional partners.
Co-investigators include Toby Owen of the University of Hawaii
University of Hawaii
The University of Hawaii System, formally the University of Hawaii and popularly known as UH, is a public, co-educational college and university system that confers associate, bachelor, master, and doctoral degrees through three university campuses, seven community college campuses, an employment...

, Andy Ingersol of Cal Tech, Fran Bagenal of the University of Colorado at Boulder
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

, and Candy Hansen of the Planetary Science Institute
Planetary Science Institute
The Planetary Science Institute is a research institute based in Tucson, Arizona, focusing on planetary science.Founded in 1972 on a non-profit basis, it is involved in many NASA missions, the study of Mars, asteroids, comets, interplanetary dust, the formation of the Solar System, extrasolar...

. Jack Connerney of the Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...

 served as instrument lead.

Launch timeline

The Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...

 (AV-029) Russian-designed RD-180 main engine, powered by kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

 and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...

, was started and underwent checkout 3.8 seconds prior to the ignition of five strap-on solid rocket booster
Solid rocket booster
Solid rocket boosters or Solid Rocket Motors, SRM, are used to provide thrust in spacecraft launches from the launchpad up to burnout of the SRBs. Many launch vehicles include SRBs, including the Ariane 5, Atlas V , and the NASA Space Shuttle...

s (SRBs). Following SRB burnout, approximately 1 minute 33 seconds into the flight, two of the spent boosters fell away from the vehicle followed 1.5 seconds later by the remaining three. When heating levels had dropped below predetermined limits, the payload fairing
Payload fairing
Payload fairing is one of the main components of a launch vehicle. The fairing protects the payload during the ascent against the impact of the atmosphere . More recently, an additional function is to maintain the cleanroom environment for precision instruments.Outside the atmosphere the fairing is...

 that protected Juno during transit through the thickest part of the atmosphere separated, about 3 minutes 24 seconds into the flight. The Atlas V main engine cutoff 4 minutes 26 seconds after liftoff. 16 seconds later, the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 second stage ignited and burned for approximately 6 minutes, putting the satellite into an initial parking orbit
Parking orbit
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory...

.

The vehicle coasted for approximately 30 minutes, and then the Centaur was re-ignited for a second firing of 9 minutes, putting the spacecraft on an Earth escape trajectory.

Prior to separation the Centaur stage used onboard reaction engine
Reaction engine
A reaction engine is an engine or motor which provides propulsion by expelling reaction mass, in accordance with Newton's third law of motion...

s to spin Juno up to 1.4 RPM. About 54 minutes after launch, the spacecraft separated from the Centaur and began to extend its solar panels. Following the full deployment and locking of the solar panels, Junos batteries began to recharge. Successful deployment of the solar panels reduced Junos spin rate by two-thirds. The probe is spun to ensure stability during the voyage and so that all instruments on the probe are able to observe Jupiter.

The voyage to Jupiter will take five years, which will include an Earth flyby in October 2013.


Scientific objectives

The Juno spacecraft's suite of science instruments will:
  • Determine the ratio of oxygen
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

     to hydrogen
    Hydrogen
    Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

    , effectively measuring the abundance of water in Jupiter, which will help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Obtain a better estimate of Jupiter's core mass, which will also help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Precisely map Jupiter's gravity to assess the distribution of mass in Jupiter's interior, including properties of the planet's structure and dynamics.
  • Precisely map Jupiter's magnetic field
    Magnetic field
    A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

     to assess the origin and structure of the field and how deep in Jupiter the magnetic field is created. This experiment also will help scientists understand the fundamental physics of dynamo theory
    Dynamo theory
    In geophysics, dynamo theory proposes a mechanism by which a celestial body such as the Earth or a star generates a magnetic field. The theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time...

    .
  • Map the variation in atmospheric composition, temperature, structure, cloud opacity and dynamics to pressures far greater than 100 bars
    Bar (unit)
    The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...

     (10 MPa
    Pascal (unit)
    The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

    ; 1450 pound/sq inch) at all latitudes.
  • Characterize and explore the three-dimensional structure of Jupiter's polar magnetosphere
    Magnetosphere
    A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

     and its auroras
    Aurora (astronomy)
    An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

    .

Orbit

The probe's planned polar orbit is highly elongated and takes it close to the poles — within 4300 kilometres (2,672 mi) — but then far beyond even Callisto
Callisto (moon)
Callisto named after the Greek mythological figure of Callisto) is a moon of the planet Jupiter. It was discovered in 1610 by Galileo Galilei. It is the third-largest moon in the Solar System and the second largest in the Jovian system, after Ganymede. Callisto has about 99% the diameter of the...

's orbit.

This type of orbit helps the craft avoid any long term contact with Jupiter's radiation belts, which can cause damage to spacecraft electronics and solar panels. The "Juno Radiation Vault," with 1 cm thick titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 walls, will also aid in protecting and shielding Juno's electronics.
The spacecraft is planned to complete at least 33 polar orbits, each taking from fourteen to eleven days.

Scientific instruments

The Juno mission's science objectives will be achieved with a payload of nine instruments onboard the spacecraft:
{| class="wikitable"
|-
! scope="col" style="width:135px;"| Instrument Name
! scope="col" style="width:50px;"| Abr.

! Description
|-
|
Microwave radiometer
Microwave radiometer
A microwave radiometer is a radiometer that measures energy emitted at sub-millimetre-to-centimetre wavelengths known as microwaves. Their primary application has been onboard spacecraft measuring atmospheric and terrestrial radiation, and they are mostly used for meteorological or oceanographic...


|
MWR

Juno is a NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 New Frontiers
New Frontiers program
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of researching several of the Sun's planets including Jupiter, Venus, and the dwarf planet Pluto...

 mission to the planet Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

. Juno was launched from Cape Canaveral Air Force Station on August 5, 2011. The spacecraft is to be placed in a polar orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...

 to study the planet's composition, gravity field, magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

, and polar magnetosphere
Jupiter's magnetosphere
The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary...

. Juno will also search for clues about how Jupiter formed, including whether the planet has a rocky core, the amount of water present within the deep atmosphere, and how the planet's mass is distributed. It will also study Jupiter's deep winds, which can reach speeds of 600 kilometres per hour (372.8 mph).

The spacecraft's name comes from Greco-Roman mythology. The god Jupiter
Jupiter (mythology)
In ancient Roman religion and myth, Jupiter or Jove is the king of the gods, and the god of the sky and thunder. He is the equivalent of Zeus in the Greek pantheon....

 drew a veil of clouds around himself to hide his mischief, but his wife, the goddess Juno
Juno (mythology)
Juno is an ancient Roman goddess, the protector and special counselor of the state. She is a daughter of Saturn and sister of the chief god Jupiter and the mother of Mars and Vulcan. Juno also looked after the women of Rome. Her Greek equivalent is Hera...

, was able to peer through the clouds and see Jupiter's true nature.

Mission summary

Juno requires a five-year cruise to Jupiter, arriving around July 4, 2016. The spacecraft will travel roughly over a total distance of 1,740 million miles (2,800 million kilometers). The spacecraft will orbit Jupiter 33 times during one Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 year. Junos trajectory will use a gravity assist speed boost from Earth, accomplished through an Earth flyby
Flyby
Flyby may refer to:* Flypast or flyover, a celebratory display or ceremonial flight* Planetary flyby, a type of interplanetary spacecraft mission* Gravity assist, a spaceflight maneuver* "Fly by II", a single released by the UK band Blue...

 two years (October 2013) after its August 5, 2011 launch. In 2016, the spacecraft will perform an orbit insertion burn to slow the spacecraft enough to allow capture into an 11-day polar orbit.
Once Juno enters into its orbit, infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 and microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 instruments will begin to measure the thermal radiation emanating from deep within Jupiter's atmosphere
Atmosphere of Jupiter
The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide and water. Although water is...

. These observations will complement previous studies of the planet's composition by assessing the abundance and distribution of water, and therefore oxygen. While filling missing pieces of the puzzle of Jupiter's composition, these data will also provide insight into the planet's origins. Juno will also investigate the convection that drives general circulation patterns in Jupiter's atmosphere. Meanwhile, other instruments aboard Juno will gather data about the planet's gravitational field and polar magnetosphere. The Juno mission is set to conclude in October 2017, after completing 33 orbits around Jupiter, when the probe will be de-orbited to crash into Jupiter.

Team

Scott Bolton
Scott Bolton (engineer)
Dr. Scott Bolton is Director of the Southwest Research Institute's Space Science and Engineering Division. He is currently the principal investigator for Juno, a mission to study Jupiter's magnetic and gravitational fields, part of NASA's New Frontiers program to explore the outer planets of the...

 of the Southwest Research Institute
Southwest Research Institute
Southwest Research Institute , headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States...

 in San Antonio, Texas is the principal investigator and is responsible for all aspects of the mission. The Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 in California manages the mission and Lockheed Martin Corporation is responsible for the spacecraft development and construction. The mission is being carried out with the participation of several institutional partners.
Co-investigators include Toby Owen of the University of Hawaii
University of Hawaii
The University of Hawaii System, formally the University of Hawaii and popularly known as UH, is a public, co-educational college and university system that confers associate, bachelor, master, and doctoral degrees through three university campuses, seven community college campuses, an employment...

, Andy Ingersol of Cal Tech, Fran Bagenal of the University of Colorado at Boulder
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

, and Candy Hansen of the Planetary Science Institute
Planetary Science Institute
The Planetary Science Institute is a research institute based in Tucson, Arizona, focusing on planetary science.Founded in 1972 on a non-profit basis, it is involved in many NASA missions, the study of Mars, asteroids, comets, interplanetary dust, the formation of the Solar System, extrasolar...

. Jack Connerney of the Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...

 served as instrument lead.

Launch timeline

The Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...

 (AV-029) Russian-designed RD-180 main engine, powered by kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

 and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...

, was started and underwent checkout 3.8 seconds prior to the ignition of five strap-on solid rocket booster
Solid rocket booster
Solid rocket boosters or Solid Rocket Motors, SRM, are used to provide thrust in spacecraft launches from the launchpad up to burnout of the SRBs. Many launch vehicles include SRBs, including the Ariane 5, Atlas V , and the NASA Space Shuttle...

s (SRBs). Following SRB burnout, approximately 1 minute 33 seconds into the flight, two of the spent boosters fell away from the vehicle followed 1.5 seconds later by the remaining three. When heating levels had dropped below predetermined limits, the payload fairing
Payload fairing
Payload fairing is one of the main components of a launch vehicle. The fairing protects the payload during the ascent against the impact of the atmosphere . More recently, an additional function is to maintain the cleanroom environment for precision instruments.Outside the atmosphere the fairing is...

 that protected Juno during transit through the thickest part of the atmosphere separated, about 3 minutes 24 seconds into the flight. The Atlas V main engine cutoff 4 minutes 26 seconds after liftoff. 16 seconds later, the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 second stage ignited and burned for approximately 6 minutes, putting the satellite into an initial parking orbit
Parking orbit
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory...

.

The vehicle coasted for approximately 30 minutes, and then the Centaur was re-ignited for a second firing of 9 minutes, putting the spacecraft on an Earth escape trajectory.

Prior to separation the Centaur stage used onboard reaction engine
Reaction engine
A reaction engine is an engine or motor which provides propulsion by expelling reaction mass, in accordance with Newton's third law of motion...

s to spin Juno up to 1.4 RPM. About 54 minutes after launch, the spacecraft separated from the Centaur and began to extend its solar panels. Following the full deployment and locking of the solar panels, Junos batteries began to recharge. Successful deployment of the solar panels reduced Junos spin rate by two-thirds. The probe is spun to ensure stability during the voyage and so that all instruments on the probe are able to observe Jupiter.

The voyage to Jupiter will take five years, which will include an Earth flyby in October 2013.


Scientific objectives

The Juno spacecraft's suite of science instruments will:
  • Determine the ratio of oxygen
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

     to hydrogen
    Hydrogen
    Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

    , effectively measuring the abundance of water in Jupiter, which will help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Obtain a better estimate of Jupiter's core mass, which will also help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Precisely map Jupiter's gravity to assess the distribution of mass in Jupiter's interior, including properties of the planet's structure and dynamics.
  • Precisely map Jupiter's magnetic field
    Magnetic field
    A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

     to assess the origin and structure of the field and how deep in Jupiter the magnetic field is created. This experiment also will help scientists understand the fundamental physics of dynamo theory
    Dynamo theory
    In geophysics, dynamo theory proposes a mechanism by which a celestial body such as the Earth or a star generates a magnetic field. The theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time...

    .
  • Map the variation in atmospheric composition, temperature, structure, cloud opacity and dynamics to pressures far greater than 100 bars
    Bar (unit)
    The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...

     (10 MPa
    Pascal (unit)
    The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

    ; 1450 pound/sq inch) at all latitudes.
  • Characterize and explore the three-dimensional structure of Jupiter's polar magnetosphere
    Magnetosphere
    A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

     and its auroras
    Aurora (astronomy)
    An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

    .

Orbit

The probe's planned polar orbit is highly elongated and takes it close to the poles — within 4300 kilometres (2,672 mi) — but then far beyond even Callisto
Callisto (moon)
Callisto named after the Greek mythological figure of Callisto) is a moon of the planet Jupiter. It was discovered in 1610 by Galileo Galilei. It is the third-largest moon in the Solar System and the second largest in the Jovian system, after Ganymede. Callisto has about 99% the diameter of the...

's orbit.

This type of orbit helps the craft avoid any long term contact with Jupiter's radiation belts, which can cause damage to spacecraft electronics and solar panels. The "Juno Radiation Vault," with 1 cm thick titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 walls, will also aid in protecting and shielding Juno's electronics.
The spacecraft is planned to complete at least 33 polar orbits, each taking from fourteen to eleven days.

Scientific instruments

The Juno mission's science objectives will be achieved with a payload of nine instruments onboard the spacecraft:
{| class="wikitable"
|-
! scope="col" style="width:135px;"| Instrument Name
! scope="col" style="width:50px;"| Abr.

! Description
|-
|
Microwave radiometer
Microwave radiometer
A microwave radiometer is a radiometer that measures energy emitted at sub-millimetre-to-centimetre wavelengths known as microwaves. Their primary application has been onboard spacecraft measuring atmospheric and terrestrial radiation, and they are mostly used for meteorological or oceanographic...


|
MWR

Juno is a NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 New Frontiers
New Frontiers program
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of researching several of the Sun's planets including Jupiter, Venus, and the dwarf planet Pluto...

 mission to the planet Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

. Juno was launched from Cape Canaveral Air Force Station on August 5, 2011. The spacecraft is to be placed in a polar orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...

 to study the planet's composition, gravity field, magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

, and polar magnetosphere
Jupiter's magnetosphere
The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetosphere is the largest and most powerful of any planetary...

. Juno will also search for clues about how Jupiter formed, including whether the planet has a rocky core, the amount of water present within the deep atmosphere, and how the planet's mass is distributed. It will also study Jupiter's deep winds, which can reach speeds of 600 kilometres per hour (372.8 mph).

The spacecraft's name comes from Greco-Roman mythology. The god Jupiter
Jupiter (mythology)
In ancient Roman religion and myth, Jupiter or Jove is the king of the gods, and the god of the sky and thunder. He is the equivalent of Zeus in the Greek pantheon....

 drew a veil of clouds around himself to hide his mischief, but his wife, the goddess Juno
Juno (mythology)
Juno is an ancient Roman goddess, the protector and special counselor of the state. She is a daughter of Saturn and sister of the chief god Jupiter and the mother of Mars and Vulcan. Juno also looked after the women of Rome. Her Greek equivalent is Hera...

, was able to peer through the clouds and see Jupiter's true nature.

Mission summary

Juno requires a five-year cruise to Jupiter, arriving around July 4, 2016. The spacecraft will travel roughly over a total distance of 1,740 million miles (2,800 million kilometers). The spacecraft will orbit Jupiter 33 times during one Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 year. Junos trajectory will use a gravity assist speed boost from Earth, accomplished through an Earth flyby
Flyby
Flyby may refer to:* Flypast or flyover, a celebratory display or ceremonial flight* Planetary flyby, a type of interplanetary spacecraft mission* Gravity assist, a spaceflight maneuver* "Fly by II", a single released by the UK band Blue...

 two years (October 2013) after its August 5, 2011 launch. In 2016, the spacecraft will perform an orbit insertion burn to slow the spacecraft enough to allow capture into an 11-day polar orbit.
Once Juno enters into its orbit, infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 and microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 instruments will begin to measure the thermal radiation emanating from deep within Jupiter's atmosphere
Atmosphere of Jupiter
The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide and water. Although water is...

. These observations will complement previous studies of the planet's composition by assessing the abundance and distribution of water, and therefore oxygen. While filling missing pieces of the puzzle of Jupiter's composition, these data will also provide insight into the planet's origins. Juno will also investigate the convection that drives general circulation patterns in Jupiter's atmosphere. Meanwhile, other instruments aboard Juno will gather data about the planet's gravitational field and polar magnetosphere. The Juno mission is set to conclude in October 2017, after completing 33 orbits around Jupiter, when the probe will be de-orbited to crash into Jupiter.

Team

Scott Bolton
Scott Bolton (engineer)
Dr. Scott Bolton is Director of the Southwest Research Institute's Space Science and Engineering Division. He is currently the principal investigator for Juno, a mission to study Jupiter's magnetic and gravitational fields, part of NASA's New Frontiers program to explore the outer planets of the...

 of the Southwest Research Institute
Southwest Research Institute
Southwest Research Institute , headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States...

 in San Antonio, Texas is the principal investigator and is responsible for all aspects of the mission. The Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 in California manages the mission and Lockheed Martin Corporation is responsible for the spacecraft development and construction. The mission is being carried out with the participation of several institutional partners.
Co-investigators include Toby Owen of the University of Hawaii
University of Hawaii
The University of Hawaii System, formally the University of Hawaii and popularly known as UH, is a public, co-educational college and university system that confers associate, bachelor, master, and doctoral degrees through three university campuses, seven community college campuses, an employment...

, Andy Ingersol of Cal Tech, Fran Bagenal of the University of Colorado at Boulder
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

, and Candy Hansen of the Planetary Science Institute
Planetary Science Institute
The Planetary Science Institute is a research institute based in Tucson, Arizona, focusing on planetary science.Founded in 1972 on a non-profit basis, it is involved in many NASA missions, the study of Mars, asteroids, comets, interplanetary dust, the formation of the Solar System, extrasolar...

. Jack Connerney of the Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...

 served as instrument lead.

Launch timeline

The Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...

 (AV-029) Russian-designed RD-180 main engine, powered by kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

 and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...

, was started and underwent checkout 3.8 seconds prior to the ignition of five strap-on solid rocket booster
Solid rocket booster
Solid rocket boosters or Solid Rocket Motors, SRM, are used to provide thrust in spacecraft launches from the launchpad up to burnout of the SRBs. Many launch vehicles include SRBs, including the Ariane 5, Atlas V , and the NASA Space Shuttle...

s (SRBs). Following SRB burnout, approximately 1 minute 33 seconds into the flight, two of the spent boosters fell away from the vehicle followed 1.5 seconds later by the remaining three. When heating levels had dropped below predetermined limits, the payload fairing
Payload fairing
Payload fairing is one of the main components of a launch vehicle. The fairing protects the payload during the ascent against the impact of the atmosphere . More recently, an additional function is to maintain the cleanroom environment for precision instruments.Outside the atmosphere the fairing is...

 that protected Juno during transit through the thickest part of the atmosphere separated, about 3 minutes 24 seconds into the flight. The Atlas V main engine cutoff 4 minutes 26 seconds after liftoff. 16 seconds later, the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 second stage ignited and burned for approximately 6 minutes, putting the satellite into an initial parking orbit
Parking orbit
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory...

.

The vehicle coasted for approximately 30 minutes, and then the Centaur was re-ignited for a second firing of 9 minutes, putting the spacecraft on an Earth escape trajectory.

Prior to separation the Centaur stage used onboard reaction engine
Reaction engine
A reaction engine is an engine or motor which provides propulsion by expelling reaction mass, in accordance with Newton's third law of motion...

s to spin Juno up to 1.4 RPM. About 54 minutes after launch, the spacecraft separated from the Centaur and began to extend its solar panels. Following the full deployment and locking of the solar panels, Junos batteries began to recharge. Successful deployment of the solar panels reduced Junos spin rate by two-thirds. The probe is spun to ensure stability during the voyage and so that all instruments on the probe are able to observe Jupiter.

The voyage to Jupiter will take five years, which will include an Earth flyby in October 2013.


Scientific objectives

The Juno spacecraft's suite of science instruments will:
  • Determine the ratio of oxygen
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

     to hydrogen
    Hydrogen
    Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

    , effectively measuring the abundance of water in Jupiter, which will help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Obtain a better estimate of Jupiter's core mass, which will also help distinguish among prevailing theories linking the gas giant's formation to the solar system.
  • Precisely map Jupiter's gravity to assess the distribution of mass in Jupiter's interior, including properties of the planet's structure and dynamics.
  • Precisely map Jupiter's magnetic field
    Magnetic field
    A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

     to assess the origin and structure of the field and how deep in Jupiter the magnetic field is created. This experiment also will help scientists understand the fundamental physics of dynamo theory
    Dynamo theory
    In geophysics, dynamo theory proposes a mechanism by which a celestial body such as the Earth or a star generates a magnetic field. The theory describes the process through which a rotating, convecting, and electrically conducting fluid can maintain a magnetic field over astronomical time...

    .
  • Map the variation in atmospheric composition, temperature, structure, cloud opacity and dynamics to pressures far greater than 100 bars
    Bar (unit)
    The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...

     (10 MPa
    Pascal (unit)
    The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

    ; 1450 pound/sq inch) at all latitudes.
  • Characterize and explore the three-dimensional structure of Jupiter's polar magnetosphere
    Magnetosphere
    A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

     and its auroras
    Aurora (astronomy)
    An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

    .

Orbit

The probe's planned polar orbit is highly elongated and takes it close to the poles — within 4300 kilometres (2,672 mi) — but then far beyond even Callisto
Callisto (moon)
Callisto named after the Greek mythological figure of Callisto) is a moon of the planet Jupiter. It was discovered in 1610 by Galileo Galilei. It is the third-largest moon in the Solar System and the second largest in the Jovian system, after Ganymede. Callisto has about 99% the diameter of the...

's orbit.

This type of orbit helps the craft avoid any long term contact with Jupiter's radiation belts, which can cause damage to spacecraft electronics and solar panels. The "Juno Radiation Vault," with 1 cm thick titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 walls, will also aid in protecting and shielding Juno's electronics.
The spacecraft is planned to complete at least 33 polar orbits, each taking from fourteen to eleven days.

Scientific instruments

The Juno mission's science objectives will be achieved with a payload of nine instruments onboard the spacecraft:
{| class="wikitable"
|-
! scope="col" style="width:135px;"| Instrument Name
! scope="col" style="width:50px;"| Abr.

! Description
|-
|
Microwave radiometer
Microwave radiometer
A microwave radiometer is a radiometer that measures energy emitted at sub-millimetre-to-centimetre wavelengths known as microwaves. Their primary application has been onboard spacecraft measuring atmospheric and terrestrial radiation, and they are mostly used for meteorological or oceanographic...


|
MWR






| The primary goal of the radiometer is to probe the deep atmosphere of Jupiter at radio wavelengths ranging from 1.3 cm to 50 cm using six separate radiometers to measure the planet's thermal emissions.
  • Principal investigator: Mike Janssen
  • Jet Propulsion Laboratory
    Jet Propulsion Laboratory
    Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...


|-
|
Jovian Infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 Auroral Mapper

|
JIRAM






| The primary goal of JIRAM is to probe the upper layers of Jupiter's atmosphere down to pressures of 5–7 bars (72–102 pound/square inch) at infrared wavelengths in the 2–5 μm interval using an imager and a spectrometer.
  • Italian National Institute for Astrophysics
    INAF
    The Istituto Nazionale di Astrofisica , or INAF for short, is the most important Italian institution conducting scientific research in astronomy and astrophysics. Researches performed by the scientific staff of the Institute go from the study of the planets and minor bodies of the solar system up...


|-
|
Fluxgate Magnetometer

|
FGM






| The magnetic field investigation has three goals: mapping of the magnetic field, determining the dynamics of Jupiter's interior, and determination of the three-dimensional structure of the polar magnetosphere.
  • Principal investigator: Jack Connerney
  • NASA's Goddard Space Flight Center
    Goddard Space Flight Center
    The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...


|-
|
Advanced Stellar Compass

|
ASC






| Will provide accurate pointing information of the Juno spacecraft for precise mapping.
  • Principal investigator: Jack Connerney
  • NASA's Goddard Space Flight Center
    Goddard Space Flight Center
    The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...


|-
|
Jovian Auroral Distribution Experiment

|
JADE






| JADE will resolve the plasma structure of the Jovian aurora by measuring the angular, energy and compositional distributions of particles in the polar magnetosphere of Jupiter.
  • Principal investigator: David McComas
  • Southwest Research Institute
    Southwest Research Institute
    Southwest Research Institute , headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States...

     

|-
|
Jovian Energetic Particle Detector Instrument

|
JEDI






| JEDI will measure the energy and angular distribution of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

, helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

, sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

 and other ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s in the polar magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

 of Jupiter.
  • Principal investigator: Barry Mauk
  • Applied Physics Laboratory
    Applied Physics Laboratory
    The Johns Hopkins University Applied Physics Laboratory , located in Howard County, Maryland near Laurel and Columbia, is a not-for-profit, university-affiliated research center employing 4,500 people. APL is primarily a defense contractor. It serves as a technical resource for the Department of...

     

|-
|
Radio and Plasma Wave
Waves in plasmas
Waves in plasmas are an interconnected set of particles and fields which propagates in a periodically repeating fashion. A plasma is a quasineutral, electrically conductive fluid. In the simplest case, it is composed of electrons and a single species of positive ions, but it may also contain...

 Sensor

|
WAVES






| This instrument will identify the regions of auroral currents that define Jovian radio emissions and acceleration of the auroral particles by measuring the radio and plasma spectra in the auroral region.
  • Principal investigator: William Kurth
  • University of Iowa
    University of Iowa
    The University of Iowa is a public state-supported research university located in Iowa City, Iowa, United States. It is the oldest public university in the state. The university is organized into eleven colleges granting undergraduate, graduate, and professional degrees...


|-
|
Ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 Imaging Spectrograph

|
UVS






| UVS will record the wavelength, position and arrival time of detected ultraviolet photons during the time when the spectrograph slit views Jupiter during each turn of the spacecraft. Using a 1024 × 256 micro channel plate (MCP) detector, it will provide spectral images of the UV auroral emissions in the polar magnetosphere.
  • Principal investigator: G. Randall Gladstone
  • Southwest Research Institute
    Southwest Research Institute
    Southwest Research Institute , headquartered in San Antonio, Texas, is one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States...


|-
|
JunoCam
JunoCam
JunoCam is a visible-light camera/telescope for the Juno Jupiter Orbiter, a NASA space probe to the planet Jupiter launched on 5 August 2011...

 

|
JCM






| A visible light camera/telescope, included in the payload to facilitate education and public outreach. It will operate for only seven orbits around Jupiter because of the planet's damaging radiation and magnetic field.
  • Principal investigator: Michael C. Malin
    Michael C. Malin
    Michael C. Malin is an American astronomer, space-scientist, and CEO of Malin Space Science Systems. His cameras have been important scientific instruments in the Exploration of Mars....

     
  • Malin Space Science Systems
    Malin Space Science Systems
    Malin Space Science Systems is a San Diego, California company that designs, develops, and operates instruments to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Michael C. Malin....


|}

Solar panels

Juno is the first mission to Jupiter using solar panel
Photovoltaic module
A solar panel is a packaged, connected assembly of solar cells, also known as photovoltaic cells...

s instead of the radioisotope thermoelectric generator
Radioisotope thermoelectric generator
A radioisotope thermoelectric generator is an electrical generator that obtains its power from radioactive decay. In such a device, the heat released by the decay of a suitable radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples.RTGs can be...

s (RTGs) used by Pioneer 10
Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...

, Pioneer 11
Pioneer 11
Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...

, the Voyager program
Voyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...

, Cassini–Huygens, and the Galileo orbiter
Galileo spacecraft
Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989 by the Space Shuttle Atlantis on the STS-34 mission...

. Once in orbit around Jupiter, Juno will receive 4% as much sunlight as we do on Earth, but advances made in both solar cell technology and efficiency over the past several decades makes it economically feasible to use solar panels of practical size to provide power at a distance of 5 AU from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

.

The Juno spacecraft uses three solar arrays symmetrically arranged around the spacecraft, which were stowed against the sides of the spacecraft for launch. Shortly after the spacecraft cleared Earth's atmosphere the arrays were deployed. Two of the arrays have four hinged segments each, and the third array has three segments with a magnetometer
Magnetometer
A magnetometer is a measuring instrument used to measure the strength or direction of a magnetic field either produced in the laboratory or existing in nature...

 in place of the fourth segment. Each panel or array is 2.7 metres (8.9 ft), by 8.9 metres (29.2 ft) long, the biggest on any NASA deep-space probe. One of the panels is slightly narrower than the others; this is to facilitate their stowage for launch. These smaller panels are 2.091 metres (6.9 ft) wide. The total area of the arrays is 60 square metres (645.8 sq ft). If the arrays were optimized to operate at Earth, they would produce 12 to 14 kilowatts of power. Only 486 W will be generated when Juno arrives at Jupiter, declining to 420 W as radiation degrades the cells. The solar panels will remain in sunlight continuously from launch through to the end of the mission, except for short periods during the operation of the main engine.

A central power distribution and drive unit monitors the power that is generated by the solar arrays, distributes it to instruments, heaters and experiment sensors as well as batteries that are charged when excess power is available. Two 55 amp-hour Lithium-Ion batteries will provide power to the vehicle when it passes through eclipse. Those batteries will be able to withstand the radiation environment of Jupiter.

Telecommunications

Junos telecommunication systems have more in common with New Horizons
New Horizons
New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...

 than with Cassini–Huygens spacecraft. Juno supports tone fault signalling for cruise mode operations, but it is expected to be used less often. Communications are via the 70 m antennae of the Deep Space Network
Deep Space Network
The Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected...

 (DSN) utilizing an X-band direct link. The Command & Data processing of the Juno spacecraft includes a flight computer capable of providing ~50 Mbit/s of instrument throughput. Gravity science subsystems use X-band and Ka-band
Ka band
The Ka band covers the frequencies of 26.5–40 GHz. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above" — in other words, the band directly above the K-band...

 doppler tracking and autoranging.

Propulsion system

Juno uses a bipropellant Leros-1b main engine that uses hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...

 and nitrogen tetroxide for propulsion and provides a thrust of 645 newtons. It is fixed to the spacecraft body and is used for major burns. The engine bell is enclosed in a debris shield. Juno utilizes a monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...

 reaction control system
Reaction control system
A reaction control system is a subsystem of a spacecraft whose purpose is attitude control and steering by the use of thrusters. An RCS system is capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow...

 (RCS) consisting of twelve jets that are mounted on four rocket engine modules. These thrusters are used for control of the vehicle’s orientation and to perform trajectory correction maneuvers.

Galileo's plaque and LEGO figurines

Juno carries a plaque to Jupiter dedicated to Galileo Galilei
Galileo Galilei
Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...

. The plaque was provided by the Italian Space Agency
Italian Space Agency
The Italian Space Agency is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy...

 and measures 2.8 by. It is made of flight-grade aluminum and weighs 6 gram (0.211643772630672 oz). The plaque depicts a self-portrait of Galileo and a text in Galileo's own hand, penned in January 1610, while observing what would later be known to be the Galilean moons
Galilean moons
The Galilean moons are the four moons of Jupiter discovered by Galileo Galilei in January 1610. They are the largest of the many moons of Jupiter and derive their names from the lovers of Zeus: Io, Europa, Ganymede and Callisto. Ganymede, Europa and Io participate in a 1:2:4 orbital resonance...

. The text translates as:
The spacecraft also carries three LEGO
Lego
Lego is a line of construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. The company's flagship product, Lego, consists of colorful interlocking plastic bricks and an accompanying array of gears, minifigures and various other parts...

 figurines representing Galileo, the Roman god Jupiter and his wife Juno. In Roman mythology, Jupiter drew a veil of clouds around himself to hide his mischief. From Mount Olympus
Mount Olympus
Mount Olympus is the highest mountain in Greece, located on the border between Thessaly and Macedonia, about 100 kilometres away from Thessaloniki, Greece's second largest city. Mount Olympus has 52 peaks. The highest peak Mytikas, meaning "nose", rises to 2,917 metres...

, Juno was able to look into the clouds and reveal her husband's real nature. Juno holds a magnifying glass as a sign for searching for the truth and her husband holds a lightning bolt. The third LEGO crew member, Galileo Galilei, has his telescope with him on the journey.

Although most LEGO toys are made of plastic, LEGO made these figures of aluminium to endure the extreme conditions of space flight.

Cost

Juno was originally proposed at a cost of approximately US$700 million (FY03) for a June 2009 launch. NASA budgetary restrictions resulted in postponement until August 2011, and a launch on board an Atlas V rocket in the 551 configuration. , the mission was projected to cost $1.1 billion over its life.

See also

  • Atmosphere of Jupiter
    Atmosphere of Jupiter
    The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide and water. Although water is...

  • Comet Shoemaker-Levy 9
    Comet Shoemaker-Levy 9
    Comet Shoemaker–Levy 9 was a comet that broke apart and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of solar system objects. This generated a large amount of coverage in the popular media, and the comet was closely observed by...

  • Exploration of Jupiter
    Exploration of Jupiter
    The exploration of Jupiter has to date been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, , has continued with seven further spacecraft missions...

  • Moons of Jupiter
  • Galileo
  • Europa Jupiter System Mission
  • Cassini–Huygens, New Horizons
    New Horizons
    New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...

    , Ulysses
  • Pioneer 10
    Pioneer 10
    Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...

    , Pioneer 11
    Pioneer 11
    Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...

    , Voyager 1
    Voyager 1
    The Voyager 1 spacecraft is a 722-kilogram space probe launched by NASA in 1977, to study the outer Solar System and eventually interstellar space. Operating for as of today , the spacecraft receives routine commands and transmits data back to the Deep Space Network. At a distance of as of...

    , Voyager 2
    Voyager 2
    The Voyager 2 spacecraft is a 722-kilogram space probe launched by NASA on August 20, 1977 to study the outer Solar System and eventually interstellar space...

  • 3 Juno
    3 Juno
    Juno , formal designation 3 Juno in the Minor Planet Center catalogue system, was the third asteroid to be discovered and is one of the larger main-belt asteroids, being one of the two largest stony asteroids, along with 15 Eunomia. Juno is estimated to contain 1% of the total mass of the asteroid...

    , a large asteroid

External links

on NASA.gov
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