UVS (Juno)

Juno's UVS instrument
Ultraviolet image of Jupiter's aurora; the bright spot at far left is the end of field line to Io; spots at bottom lead to Ganymede and Europa. This was taken by the Hubble Space Telescope from Earth orbit, using the Space Telescope Imaging Spectrograph
Here is an observation of Jupiter in X-rays by Chandra. CXO's high angular resolution provided a theory-challenging breakthrough—why were the emissions coming from the poles?[1]
Distribution of acetylene at Jupiter's poles; this data was collected by the CIRS instrument on the Cassini spacecraft during its 2001 flyby of Jupiter.[2]

UVS, known as the Ultraviolet Spectrograph[3] or Ultraviolet Imaging Spectrometer[4] is the name of an instrument on the Juno orbiter for Jupiter.[3] The instrument is an imaging spectrometer that observes the ultraviolet range of light wavelengths, which is shorter wavelengths than visible light but longer than X-rays.[5] Specifically, it is focused on making remote observations of the aurora, detecting the emissions of gases such as hydrogen in the far-ultraviolet.[5] 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.[5] The source of aurora emissions of Jupiter is one of the goals of the instrument.[6] 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.[7] With both instruments operating together, both the UV emissions and high-energy particles at the same place and time can be synthesized.[7] This supports the Goal of determining the source of the Jovian magnetic field.[7] 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.[1] Every 45 minutes an X-ray hot-spot pulsates, corroborated by a similar previous detection in radio emissions by Galileo and Cassini spacecraft.[1] One theory is that its related to the solar wind.[8] 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.[9]

There is two main parts to UVS, the optical section and an electronics box.[5][10] It has a small reflecting telescope and also a scan mirror, and it can do long-slit spectrography.[11] UVS uses a Rowland circle spectrograph and a toroidal holographical grating.[5][12] The detector uses a micro-channel plate detector with the sensor being a CsI photocathode to detect the UV light[5][12]

UVS was launched aboard the Juno spacecraft on August 5, 2011 (UTC) from Cape Canaveral, USA, as part of the New Frontiers program,[13] and after an interplanetary journey that including a swingby of Earth, entered a polar orbit of Jupiter on July 5, 2016 (UTC),[14][15]

For detection of following gasses in the far UV:[5]

UVS is similar to ultraviolet spectrometers flown on New Horizons (Pluto probe), Rosetta (comet probe) and the Lunar Reconnaissance Orbiter.[11] One of the changes is shielding to help the instrument endure Jupiter's radiation environment.[11]

The electronics are located inside the Juno Radiation Vault, which uses titanium to protect it and other spacecraft electronics.[10][16] The UVS electronics include two power supplies and data processing.[16] UVS electronics box uses an Actel 8051 microcontroller.[16]

UVS was developed at the Space Science Department at Southwest Research Institute[17]

UVIS data in concert with JEDI observations detected electrical potentials of 400,000 electron volts (400 keV), 20-30 times higher than Earth, driving charged particles into the polar regions of Jupiter.[18]

There was a proposal to use Juno's UVS (and JIRAM) in collaboration with the Hubble Space Telescope instruments STIS and ACS to study Jupiter aurora in UV.[19]

  1. ^ a b c "Chandra :: Photo Album :: Jupiter :: 27 Feb 02". chandra.harvard.edu. Retrieved 6 January 2017.
  2. ^ "Catalog Page for PIA13699". JPL - Photojournal. 29 December 2010. Retrieved 28 March 2020.
  3. ^ a b Gladstone, G. R.; Persyn, S.; Eterno, J.; Slater, D. C.; Davis, M. W.; Versteeg, M. H.; Persson, K. B.; Siegmund, O. H.; Marquet, B. (1 December 2008). "The Ultraviolet Spectrograph (UVS) on Juno". AGU Fall Meeting Abstracts. 41: SM41B–1678. Bibcode:2008AGUFMSM41B1678G.
  4. ^ "Juno's Instruments | Mission Juno". Mission Juno. Retrieved 6 January 2017.
  5. ^ a b c d e f g The Ultraviolet Spectrograph (UVS) on Juno - Gladstone, et al
  6. ^ "International Workshop on Instrumentation for Planetary Missions" (PDF). Southwest Research Institute. 2012. Retrieved 28 March 2020.
  7. ^ a b c "The Juno Mission to Jupiter". Space.com. Retrieved 6 January 2017.
  8. ^ Anderson, Natali (23 March 2016). "Researchers Find What Causes Jupiter's X-ray Aurora". sci-news.com. Retrieved 28 March 2020.
  9. ^ "Puzzling X-rays from Jupiter | Science Mission Directorate". science.nasa.gov. Retrieved 6 January 2017.
  10. ^ a b Key and Driving Requirements for the Juno Payload Suite of Instruments
  11. ^ a b c Gladstone, G. Randall; Persyn, Steven C.; Eterno, John S.; Walther, Brandon C.; Slater, David C.; Davis, Michael W.; Versteeg, Maarten H.; Persson, Kristian B.; Young, Michael K. (25 March 2014). "The Ultraviolet Spectrograph on NASA's Juno Mission". Space Science Reviews. 213 (1–4): 447–473. Bibcode:2017SSRv..213..447G. doi:10.1007/s11214-014-0040-z. ISSN 0038-6308.
  12. ^ a b "Instrument Overview – Juno". spaceflight101.com. Retrieved 6 January 2017.
  13. ^ Dunn, Marcia (5 August 2011). "NASA probe blasts off for Jupiter after launch-pad snags". NBC News. Archived from the original on 11 December 2013. Retrieved 31 August 2011.
  14. ^ Chang, Kenneth (5 July 2016). "NASA's Juno Spacecraft Enters Jupiter's Orbit". The New York Times. Retrieved 5 July 2016.
  15. ^ Chang, Kenneth (28 June 2016). "NASA's Juno Spacecraft Will Soon Be in Jupiter's Grip". The New York Times. Retrieved 30 June 2016.
  16. ^ a b c "Instrument Overview – Juno". spaceflight101.com. Retrieved 27 January 2017.
  17. ^ "Southwest Research Institute (SwRI) 2011 News Release - Juno spacecraft to Jupiter prepares to launch". www.swri.org. 19 July 2016. Retrieved 27 January 2017.
  18. ^ "Juno Detects Vast Amounts of Energy over Jupiter's Auroral Regions | Planetary Science, Space Exploration | Sci-News.com". Breaking Science News | Sci-News.com. Retrieved 4 April 2018.
  19. ^ Grodent, Denis; Bonfond, Bertrand; Gérard, Jean-Claude; Randall Gladstone, G.; Nichols, Jonathan D.; Clarke, John T.; Bagenal, Fran; Adriani, Alberto (2015). "The crucial role of HST during the NASA Juno mission: A "Juno initiative"". arXiv:1503.07669 [astro-ph.EP].