MWR: Microwave Radiometer for the Juno Mission to Jupiter

Janssen, M. A.; Oswald, J.; Brown, Shannon; Gulkis, S.; Levin, S. M.; Bolton, S. J.; Allison, M.; Atreya, S. K.; Gautier, D.; Ingersoll, Andrew P.; Lunine, Jonathan I.; Orton, Glenn S.; Owen, Tobias; Steffes, Paul G.; Adumitroaie, Virgil; Bellotti, Amadeo; Jewell, L. A.; Li, C.; Li, L.; Misra, Sidharth; Oyafuso, Fabiano; Santos-Costa, Daniel; Sarkissian, E.; Williamson, R.; Arballo, J. K.; Kitiyakara, A.; Ulloa-Severino, Antonio; Chen, J. C.; Maiwald, Frank; Sahakian, A. S.; Pingree, Paula J.; Lee, K. A.; Mazer, Alan S.; Redick, Richard W.; Hodges, Richard E.; Hughes, R.C.; Bedrosian, G.; Dawson, Douglas E.; Hatch, W. A.; Russell, Damon; Chamberlain, Neil; Zawadski, M. S.; Khayatian, B.; Franklin, B. R.; Conley, Henry A.; Kempenaar, J. G.; Loo, M. S.; Sunada, Eric; Vorperion, V.; Wang, C. C.

doi:10.1007/978-94-024-1560-5_5

Cited by 19 publications

(53 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Juno MWR instrument (Janssen et al., 2017) comprises six receivers whose center frequencies are approximately equally spaced in log‐frequency over a range of 0.6 GHz (50 cm, channel 1) to 21.9 GHz (1.37 cm, channel 6). Each receiver measures the power received through the antenna in a narrow (∼3.5%) bandwidth centered on its nominal frequency and averaged over contiguous time intervals of 100 ms.…”

Section: Algorithmmentioning

confidence: 99%

“…Measurements of G ( ϑ , φ ), represented on a 1° by 1° grid, were made pre‐launch and are described in more detail in Janssen et al. (2017). The noise for each measurement varies from about 1.0 K (channel 1) to 0.2 K (channel 6), with an independent systematic error in absolute calibration of approximately 2% for each channel (Janssen et al., 2017).…”

Section: Algorithmmentioning

confidence: 99%

“…(2017). The noise for each measurement varies from about 1.0 K (channel 1) to 0.2 K (channel 6), with an independent systematic error in absolute calibration of approximately 2% for each channel (Janssen et al., 2017). The spacecraft spins at a fixed rate of approximately 2 rpm, and Jupiter and its environs are continuously scanned as the Juno spacecraft travels from north to south through periapsis.…”

Section: Algorithmmentioning

confidence: 99%

See 2 more Smart Citations

Angular Dependence and Spatial Distribution of Jupiter's Centimeter‐Wave Thermal Emission From Juno's Microwave Radiometer

Oyafuso

Levin

Orton

et al. 2020

Earth and Space Science

Self Cite

View full text Add to dashboard Cite

NASA's Juno spacecraft has been monitoring Jupiter in 53-day orbits since 2016. Its six-frequency microwave radiometer (MWR) is designed to measure black body emission from Jupiter over a range of pressures from a few tenths of a bar to several kilobars in order to retrieve details of the planet's atmospheric composition, in particular, its ammonia and water abundances. A key step toward achieving this goal is the determination of the latitudinal dependence of the nadir brightness temperature and limb darkening of Jupiter's thermal emission through a deconvolution of the measured antenna temperatures. We present a formulation of the deconvolution as an optimal estimation problem. It is demonstrated that a quadratic expression is sufficient to model the angular dependence of the thermal emission for the data set used to perform the deconvolution. Validation of the model and results from a subset of orbits favorable for MWR measurements is presented over a range of latitudes that cover up to 60°f rom the equator. A heuristic algorithm to mitigate the effects of nonthermal emission is also described. Plain Language Summary One of the instruments on the Juno spacecraft that is currently orbiting Jupiter every 53 days is the microwave radiometer (MWR). It has been sensing the atmosphere for the first time over a wide range of depths below the topmost clouds, covering pressures from less than the Earth's surface pressure to several thousand times that value. This enables a deeper exploration than ever before of how winds distribute gases that can condense, such as water (as in the Earth's atmosphere) and ammonia (which forms Jupiter's highest level clouds). One challenge in understanding the MWR data is to convert each of its raw measurements into an estimate of the true brightness temperature of Jupiter as though it were observed in a perfect, narrow beam, a process known as a deconvolution. We determined that this correction for the angular dependence can be done reliably with a three-term (quadratic) expression. The results of this approach have formed the basis of all of the analysis of MWR data to date, and we show some of the intriguing results from orbits that allowed for the best MWR observing geometry over latitudes that cover up to 60°from the equator.

show abstract

Section: Algorithmmentioning

confidence: 99%

Section: Algorithmmentioning

confidence: 99%

Section: Algorithmmentioning

confidence: 99%

See 1 more Smart Citation

Angular Dependence and Spatial Distribution of Jupiter's Centimeter‐Wave Thermal Emission From Juno's Microwave Radiometer

Oyafuso

Levin

Orton

et al. 2020

Earth and Space Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…sensitive down to approximately 100 bars or more and inclusion of such an instrument would enable measurements of the vertical distribution and abundances of gases down to this level (this approach is currently being used by the Juno mission [62]). A microwave radiometer could also be used to measure the microwave flux and map the atmospheric temperature structure at these lower levels, providing an important constraint on radiative transfer models [62]. These measurements could be achieved with a microwave radiometer similar to that on Juno [62] with frequency channels optimized for observing Uranus: 22 GHz, 10 GHz, 5.3 GHz, 1.7 GHz, 0.8 GHz.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…A microwave radiometer could also be used to measure the microwave flux and map the atmospheric temperature structure at these lower levels, providing an important constraint on radiative transfer models [62]. These measurements could be achieved with a microwave radiometer similar to that on Juno [62] with frequency channels optimized for observing Uranus: 22 GHz, 10 GHz, 5.3 GHz, 1.7 GHz, 0.8 GHz. It would have a mass of 46 kg, require 32 W of power, and cost approximately $50M.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

OCEANUS: A high science return Uranus orbiter with a low-cost instrument suite

et al. 2018

View full text Add to dashboard Cite

Ice-giant-sized planets are the most common type of observed exoplanet, yet the two ice giants in our own solar system (Uranus and Neptune) are the least explored class of planet, having only been observed through ground-based observations and a single flyby each by Voyager 2 approximately 30 years ago. These single flybys were unable to characterize the spatial and temporal variability in ice giant magnetospheres, some of the most odd and intriguing magnetospheres in the solar system. They also offered only limited constraints on the internal structure of ice giants; understanding the internal structure of a planet is important for understanding its formation and evolution. The most recent planetary science Decadal Survey by the U.S. National Academy of Sciences, "Vision and Voyages for Planetary Science in the Decade 2013-2022," identified the ice giant Uranus as the third highest priority for a Flagship mission in the decade 2013-2022. However, in the event that NASA or another space agency is unable to fly a Flagship-class mission to an ice giant in the next decade, this paper presents a mission concept for a focused, lower cost Uranus orbiter called OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System). OCEANUS would increase our understanding of the interior structure of Uranus, its magnetosphere, and how its magnetic field is generated. These goals could be achieved with just a magnetometer and the spacecraft's radio

show abstract

Multiple‐wavelength sensing of Jupiter during the Juno mission's first perijove passage

Orton

Momary

Ingersoll

et al. 2017

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

We compare Jupiter observations made around 27 August 2016 by Juno's JunoCam, Jovian Infrared Auroral Mapper (JIRAM), MicroWave Radiometer (MWR) instruments, and NASA's Infrared Telescope Facility. Visibly dark regions are highly correlated with bright areas at 5 µm, a wavelength sensitive to gaseous NH3 gas and particulate opacity at p ≤5 bars. A general correlation between 5‐µm and microwave radiances arises from a similar dependence on NH3 opacity. Significant exceptions are present and probably arise from additional particulate opacity at 5 µm. JIRAM spectroscopy and the MWR derive consistent 5‐bar NH3 abundances that are within the lower bounds of Galileo measurement uncertainties. Vigorous upward vertical transport near the equator is likely responsible for high NH3 abundances and with enhanced abundances of some disequilibrium species used as indirect indicators of vertical motions.

show abstract

MWR: Microwave Radiometer for the Juno Mission to Jupiter

Cited by 19 publications

References 65 publications

Angular Dependence and Spatial Distribution of Jupiter's Centimeter‐Wave Thermal Emission From Juno's Microwave Radiometer

Angular Dependence and Spatial Distribution of Jupiter's Centimeter‐Wave Thermal Emission From Juno's Microwave Radiometer

OCEANUS: A high science return Uranus orbiter with a low-cost instrument suite

Multiple‐wavelength sensing of Jupiter during the Juno mission's first perijove passage

Contact Info

Product

Resources

About