The Ultraviolet Spectrograph on NASA’s Juno Mission

Abstract

The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter's far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno's other remote sensing instruments and used to place in situ measurements made by Juno's particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter's magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight-the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and David C. Slater deceased 30 May 2011.

The Juno Magnetic Field Investigation

“…Finally, with a year of operations about Jupiter it may be possible to detect the secular variation of the Jovian field. If secular variation is detected, an independent measure of the depth to the dynamo may also be obtained by application of the frozen flux theorem (Hide and Malin 1981;Glatzmaier and Roberts 1996).…”

“…Juno's instrument complement thus also includes a suite of fields and particle instruments for in-situ sampling; in addition to the magnetometer, Juno carries an energetic particle detector (JEDI) measuring electrons in the energy range 40-500 keV and ions from 20 keV to >1 MeV (Mauk et al 2013), a Jovian auroral (plasma) distributions experiment (JADE) measuring electrons with energies of 0.1 to 100 keV and ions from 5 to 50 keV (McComas et al 2013), and a radio and plasma waves instrument (WAVES) recording Jovian radio emissions to >40 MHz (Kurth et al, this issue). Remote observations of the aurora will be acquired by an ultraviolet spectrometer (UVS) counting individual UV photons (Gladstone et al, 2014) and a Jupiter infrared auroral mapping instrument (JIRAM) supporting imagery and spectrometry . Juno also carries a modest imaging system (JunoCam) intended for education and public outreach (Hansen et al 2014).…”

Bar Code Events in the Juno‐UVS Data: Signature ∼10 MeV Electron Microbursts at Jupiter

“…Inspired by the study of Steffl et al (2012), here we make use of the Juno-UVS instrument (Gladstone et al, 2017), not as a UV spectrograph but as a particle detector. Indeed, the detector not only records UV photons but also impacts from relativistic electrons penetrating the instrument (Davis et al, 2016).…”

Junocam: Juno’s Outreach Camera

“…The orbit also enables one to study the equatorial clouds and winds "up close," with a spatial scale of 3 km per pixel at perijove. Finally, Junocam provides "eyes" in visible light for three other instruments, the microwave radiometer (MWR), which peers through the clouds down to 100 bar levels (Janssen et al 2014), the ultraviolet imaging spectrograph (UVS), which studies UV auroral emissions in the polar magnetosphere (Gladstone et al 2014), and the Jovian infrared auroral mapper (JIRAM), which studies IR auroral emissions and the IR emissions emanating from the clouds at all latitudes (Adriani et al 2014). …”

“…The Juno spacecraft flew by earth on October 9, 2013 for a gravity assist on its way to Jupiter (Bolton et al 2014). Junocam was powered on for ∼ 10 min to take pictures of the moon and for about an hour to take pictures of the earth.…”