UVS instrument Juno Arrival press kit 01072016 223624

UVS, known as the Ultraviolet Spectrograph or Ultraviolet Imaging Spectrometer is the name of an instrument on the ''Juno'' orbiter for Jupiter. The instrument is an

imaging spectrometer An imaging spectrometer is an instrument used in hyperspectral imaging and imaging spectroscopy to acquire a spectrally-resolved image of an object or scene, usually to support analysis of the composition the object being imaged. The spectral data ...

that observes the

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

range of light wavelengths, which is shorter wavelengths than visible light but longer than X-rays.The Ultraviolet Spectrograph (UVS) on ''Juno'' - Gladstone, et al
/ref> Specifically, it is focused on making remote observations of the

aurora An aurora ( aurorae or auroras), also commonly known as the northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in Earth's sky, predominantly observed in high-latitude regions (around the Arc ...

, detecting the emissions of gases such as

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

in the far-

. UVS will observes light from as short a wavelength as 70 nm up to 200 nm, which is in the extreme and far ultraviolet range of light. The source of aurora emissions of Jupiter is one of the goals of the instrument. UVS is one of many instruments on ''Juno'', but it is in particular designed to operate in conjunction with JADE, which observes high-energy particles. With both instruments operating together, both the UV emissions and high-energy particles at the same place and time can be synthesized. This supports the Goal of determining the source of the Jovian magnetic field. There has been a problem understanding the Jovian aurora, ever since Chandra determined X-rays were coming not from, as it was thought Io's orbit but from the polar regions. Every 45 minutes an X-ray hot-spot pulsates, corroborated by a similar previous detection in radio emissions by Galileo and Cassini spacecraft. One theory is that its related to the

solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

. The mystery is not that there are X-rays coming Jupiter, which has been known for decades, as detected by previous X-ray observatories, but rather why with the Chandra observation, that pulse was coming from the north polar region. There is two main parts to UVS, the optical section and an electronics box.Key and Driving Requirements for the ''Juno'' Payload Suite of Instruments
/ref> It has a small reflecting telescope and also a scan mirror, and it can do long-slit spectrography. UVS uses a Rowland circle spectrograph and a toroidal holographical grating. The detector uses a

micro-channel plate A microchannel plate (MCP) is used to detect single particles (electrons, ions and neutrons) and photons (ultraviolet radiation and X-rays). It is closely related to an electron multiplier, as both intensify single particles or photons by the mul ...

detector with the sensor being a CsI

photocathode A photocathode is a surface engineered to convert light (photons) into electrons using the photoelectric effect. Photocathodes are important in accelerator physics where they are utilised in a photoinjector to generate high brightness electron ...

to detect the UV light UVS was launched aboard the ''Juno'' spacecraft on August 5, 2011 (

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

) from Cape Canaveral, USA, as part of the

New Frontiers program The New Frontiers program is a series of space exploration missions being conducted by NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the ...

, and after an interplanetary journey that including a swingby of Earth, entered a

polar orbit A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of abo ...

of Jupiter on July 5, 2016 (UTC), For detection of following gasses in the far UV: *

Hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

(H) *Molecular hydrogen (H₂) *

Methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

() *

Acetylene Acetylene (Chemical nomenclature, systematic name: ethyne) is a chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is u ...

(C₂H₂) UVS is similar to ultraviolet spectrometers flown on ''

New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...

'' (Pluto probe), ''

Rosetta Rosetta ( ) or Rashid (, ; ) is a port city of the Nile Delta, east of Alexandria, in Egypt's Beheira governorate. The Rosetta Stone was discovered there in 1799. Founded around the 9th century on the site of the ancient town of Bolbitine, R ...

'' (comet probe) and the

Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric Polar orbit, polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic ...

. One of the changes is shielding to help the instrument endure Jupiter's radiation environment. The electronics are located inside the

Juno Radiation Vault Juno Radiation Vault is a compartment inside the '' Juno'' spacecraft that houses much of the probe's electronics and computers, and is intended to offer increased protection of radiation to the contents as the spacecraft endures the radiation ...

, which uses titanium to protect it and other spacecraft electronics. The UVS electronics include two power supplies and data processing. UVS electronics box uses an Actel 8051 microcontroller. UVS was developed at the Space Science Department at

Southwest Research Institute Southwest Research Institute (SwRI), headquartered in San Antonio, Texas, is an independent and nonprofit applied research and development (R&D) organization. Founded in 1947 by oil businessman Tom Slick, it provides contract research and deve ...

UVIS data in concert with JEDI observations detected electrical potentials of 400,000

electron volts In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an electric potential difference of one volt in vacuum. When u ...

(400 keV), 20-30 times higher than Earth, driving charged particles into the polar regions of Jupiter. There was a proposal to use Juno's UVS (and JIRAM) in collaboration with the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

instruments STIS and ACS to study Jupiter aurora in UV.

Observations

UVS has been used to observe aurora of Jupiter. Since UVS is on the Juno spacecraft as it orbits Jupiter, it has been able to observe both the day and night side aurora, from distance ranging from seven, to 0.05 Jupiter radii. One results as that some auroral emissions are related to the local magnetic time. Observations with the instrument have suggested that a different mechanism that understood to create Earth aurora's may be occurring. UVS observed Jupiter's Moon Io, along with several other instruments. The moon's polar regions were observed, and there was evidence of a volcanic plume.

References

External links

NASA ''Juno'' Spacecraft and InstrumentsIn-flight characterization and calibration of the Juno-Ultraviolet Spectrograph (Juno-UVS)Northern lights of Jupiter by UVS
{{Junojupiternav Spacecraft instruments Juno (spacecraft) Spectrographs Ultraviolet telescopes Extreme ultraviolet telescopes

Observations

See also

References

External links