Juno (spacecraft)

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This article is about the spacecraft. For the launch vehicle, see Juno I.

Juno is a NASA mission to Jupiter planned to cost roughly $700 million (FY03) and scheduled to launch in the summer of 2011. The spacecraft will be placed in a polar orbit in order to study the planet's composition, gravity field, magnetic field, and polar magnetosphere. Juno will also be searching for evidence to help scientists understand how Jupiter formed. Specific questions that relate to the origin of planets in our solar system include the determination of whether Jupiter has a rocky core, the amount of water present within the deep atmosphere, and how the mass is distributed within the planet. Juno will also study Jupiter's deep winds (which can reach speeds of 600 km/h).

It will be the first mission to Jupiter using solar panels instead of radioisotope thermoelectric generators.

Contents 1 Mission summary 2 Current status 3 Solar panels 4 See also 5 References 6 External links

[edit] Mission summary

Juno, which is set for launch in 2010, is a New Frontiers mission to study the planet Jupiter. Originally, JIMO was proposed to orbit Jupiter and study its environment, but due to heavy budgetary concerns and the availability of proposed nuclear power systems, NASA eventually cut funding and then cancelled it. Juno's trajectory to Jupiter utilizes a gravity assist from Earth. This is accomplished through an Earth flyby two years after launch. At arrival at Jupiter, the spacecraft will perform an orbit insertion burn to slow the spacecraft enough to allow capture into Jupiter orbit. The spacecraft will then orbit Jupiter about its poles with an 11 day orbital period.

[edit] Current status

Currently, the mission is a proposed spacecraft in the early planning stages. Although the price of the mission is lower than for most other spacecraft, a launch vehicle must be ready for Juno to be launched. Both the Atlas V rocket and Delta IV rocket have been proposed.

[edit] Solar panels

Unlike the Galileo Orbiter Juno will use solar panels rather than radioisotope thermoelectric generators. The reason for this is the significant advancement in solar cell technology and efficiency over the past several decades, which now makes it economically feasible to use solar panels of practical size to provide sufficient power at such a great distance from the sun. In addition, a short supply cut of RTGs has made them limited to space missions. Also, by using solar energy, NASA avoids the protests associated with launching RTGs into space (due to accusations of public safety risks, which NASA refutes in detailed scientific reports); however, it should be noted that NASA plans several more projects involving RTGs, and the decision to use alternate technology on this mission is more practical and economical than political.

[edit] See also

• Pioneer 10
• Voyager 2
• Galileo
• JIMO

[edit] References

[edit] External links

• Official web site
• NASA Selects New Frontiers Concept Study: Juno Mission to Jupiter at NASA Jet Propulsion Laboratory
• The Juno Mission to Jupiter at Space.com

edit Jupiter Spacecraft Missions
Flybys: Pioneer 10 | Pioneer 11 | Voyager 1 | Voyager 2 | Ulysses | Cassini
Orbiters: Galileo
Atmospheric probes: Galileo probe
Future: New Horizons | Juno
(Bold: Active missions)