Rhea is the second largest moon of Saturn, but with a mean radius of 475 miles (764 kilometers) it is less than a third the radius of Saturn's largest moon, Titan. Rhea is a small, cold, airless body that is very similar to sister moons Dione and Tethys. As with the other two moons, Rhea is tidally locked in phase with its parent — one side always faces toward Saturn — as it completes its 4.5-Earth-day orbit around the planet. Rhea's surface temperatures are also similar to Dione and Tethys, being roughly as warm as -281 degrees Fahrenheit (-174 degrees Celsius) in sunlit areas and ranging down to -364 degrees Fahrenheit (-220 degrees Celsius) in shaded areas. Also like Dione and Tethys, Rhea has a high reflectivity (or geometric albedo) suggesting a surface composition largely of water ice, which behaves like rock in Rhea's temperature range.  Rhea's density of 1.233 times that of liquid water suggests that Rhea is three quarters ice and one quarter rock.

Rhea

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data_calibration collection for the "CASSINI HIGH RATE DETECTOR" bundle

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Saturn Small Moon Shape Models V1.0

The High Rate Detector (HRD) from the   
        University of Chicago is an independent part of the CDA instrument on 
        the Cassini Orbiter that measures the dust flux and particle mass     
        distribution of dust particles hitting the HRD detectors.  This data  
        set includes all data from the HRD through the end of the mission,    
        Sept. 15, 2017.  Please refer to Srama et al. (2004) for a detailed   
        HRD description.

CASSINI HIGH RATE DETECTOR

Digital shape models have been constructed from Cassini Imaging Science Subsystem
(ISS) data for eleven of the small satellites of Saturn and delivered to the
Planetary Data System. These satellites are: Pan, Daphnis, Atlas, Prometheus,
Pandora, Epimetheus, Janus, Telesto, Calypso, Helene, and Hyperion. These models
typically have uncertainties well under 0.5 km. They are appropriate for global
geometric, geologic, and geophysical studies, and regional slope and topography
study. They are useful in studying morphologies of only the relatively largest-sized
craters. Studies based on early versions of these shape models are in Thomas et al.,
2013

The Hubble Space Telescope is a cooperative program of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) to operate a long-lived space-based observatory for the benefit of the international astronomical community. HST is an observatory first dreamt of in the 1940s, designed and built in the 1970s and 80s, and operational only in the 1990s. Since its preliminary inception, HST was designed to be a different type of mission for NASA. A permanent space-based observatory. To accomplish this goal and protect the spacecraft against instrument and equipment failures, NASA had always planned on regular servicing missions. Hubble has special grapple fixtures, 76 handholds, and stabilized in all three axes. HST is a 2.4-meter reflecting telescope which was deployed in low-Earth orbit (600 kilometers) by the crew of the space shuttle Discovery (STS-31) on 25 April 1990.

The twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing on their more-than-40-year journey since their 1977 launches, they each are much farther away from Earth and the sun than Pluto. In August 2012, Voyager 1 made the historic entry into interstellar space, the region between stars, filled with material ejected by the death of nearby stars millions of years ago. Voyager 2 entered interstellar space on November 5, 2018 and scientists hope to learn more about this region. Both spacecraft are still sending scientific information about their surroundings through the Deep Space Network, or DSN.

The primary mission was the exploration of Jupiter and Saturn. After making a string of discoveries there — such as active volcanoes on Jupiter's moon Io and intricacies of Saturn's rings — the mission was extended. Voyager 2 went on to explore Uranus and Neptune, and is still the only spacecraft to have visited those outer planets. The adventurers' current mission, the Voyager Interstellar Mission (VIM), will explore the outermost edge of the Sun's domain. And beyond.

VOYAGER

Orbiting the ringed planet Saturn and its numerous moons, the Cassini spacecraft was a keystone of exploration of the Saturnian system and the properties of gaseous planets in our solar system. 
A joint endeavor of NASA, the European Space Agency, or ESA, and the Italian Space Agency, Cassini launched in 1997 along with ESA's Huygens probe. The spacecraft contributed to studies of Jupiter for six months in 2000 before reaching its destination, Saturn, in 2004 and starting a string of flybys of Saturn's moons. That same year it released the Huygens probe on Saturn's moon Titan to conduct a study of the moon's atmosphere and surface composition. In its second extended mission, Cassini made the first observations of a complete seasonal period for Saturn and its moons, flew between the rings and descended into the planet's atmosphere.

Title	Published	Start Date	End Date
Other
CASSINI HIGH RATE DETECTOR	2006	3/25/1999	3/25/1999

shape model
Saturn Small Moon Shape Models V1.0	2018	1/1/1965	1/1/1965

Rhea Information Page

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