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Cassini-Huygens is a robotic spacecraft studying Saturn and its moons. The spacecraft has two main elements: Cassini (an orbiter developed by NASA), and Huygens (a lander developed by the European Space Agency ESA).

Cassini has been designed to remain in orbit around Saturn, while the Huygens probe was designed to be dropped through the atmosphere of Titan, Saturn’s largest moon.

Cassini reached Saturn in July 2004. With its wide array of instruments, the craft has gathered vast amounts of data about Saturn’s rings, moons and the planet itself leading to many new discoveries including a giant, continuous hurricane at Saturn’s south pole, geysers on Enceladus, one of Saturn’s many moons, and the discovery of seven previously unknown moons.

The Huygens probe had a successful descent through the atmosphere of Titan in January 2005 and revealed a surface covered by lakes and rivers of liquid hydrocarbons. The Huygens probe, although it was not intended to be a lander, continued to transmit data for 90 minutes after arriving on Titan’s surface, although an error caused Cassini to only receive data from one of the two planned radio channels.

The Cassini spacecraft is currently still orbiting Saturn and conducting fly-bys of Saturn’s moons. The mission is scheduled to end in 2017, at which time Cassini will make a controlled decent into Saturn’s atmosphere.

It was not feasible to use solar panels to power Cassini, due to Saturn’s distance from the Sun. Instead, the Cassini orbiter is powered by the radioactive decay of plutonium-238. The heat from this decay is then used to generate electricity.

The Cassini spacecraft has a reflector array that it uses to transmit data back to Earth. Saturn’s distance from Earth is vast, and signals from Cassini take 68-84 minutes to reach us.

Instruments on Cassini
  • Radar mapper
  • CCD imaging system
  • Spectrometers (visible/infrared)
  • Spectrograph (ultraviolet)
  • Magnetospheric imager
  • Magnetometer
  • Mass spectrometer
Instruments on Huygens
  • HASI: Huygens Atmospheric Structure Instrument
  • DWE: Doppler Wind Experiment
  • DISR: Descent Imager/Spectral Radiometer
  • GC/MS: Gas Chromatograph Mass Spectrometer
  • ACP: Aerosol Collector and Pyrolyser
  • SSP: Surface-Science Package

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Named after astronomer Edwin Hubble, the Hubble Space Telescope (HST or ‘Hubble’) is a telescope in orbit around the Earth since 1990. Hubble is a collaboration between NASA and the European Space Agency, and is one of the largest and most adaptable space telescopes. It is the only telescope ever designed to be serviced in space by astronauts.

Hubble has been used for a wide variety of research and observations, and has helped make many surprising discoveries over the course of its long life. There have been five missions to service Hubble in its life so far – to make repairs, upgrade technologies, and replace instruments.
The most recent servicing mission should allow Hubble to continue operating until at least 2014.

Hubble’s successor, the James Webb Space Telescope (JWST) is due to be launched in 2018. Although the JWST will be superior to Hubble for research, it will only observe in infrared light, and won’t be able to observe visible and ultraviolet light like the Hubble currently does.
what will this mean in terms of the images it returns?

Hubble is powered by the Sun, using solar panels that are attached to the instrument. Hubble’s original solar panels were replaced with newer, more efficient ones during one of the service missions.

General Information
  • Launch date: 24 April 1990
  • Launch vehicle: Space Shuttle Discovery (STS-31)
  • Mass: 11,110 kg
  • Location: Low Earth Orbit (559 km above the Earth, orbiting once every 96-97 minutes)
  • Speed: 7.5 km/s
  • Telescope type: Ritchey-Chretien Reflector
  • Mirror size: 2.4 m in diameter
  • NICMOS: Infrared Camera/Spectrometer
  • ACS: Optical Survey Camera
  • WFC3: Wide Field Optical Camera
  • COS: Ultraviolet Spectrograph
  • STIS: Optical Spectrometer/Camera
  • FGS: Fine Guidance Sensors (3)

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