Hubble Space Telescope Instruments

The Hubble Space Telescope carries a number of important instruments to carry out its multiple missions:

• The Wide Field and Planetary Camera II (WFPC2)
• Advanced Camera for Surveys (ACS)
• Near Infrared Camera and Multi-object Spectrometer (NICMOS)

Advanced Camera for Surveys

One of the Hubble Space Telescope's advanced instruments is referred to as the ACS. Hubble's newest science instrument-the Advanced Camera for Surveys - brought the telescope into the 21st century. With its wider field of view, sharper image quality, and enhanced sensitivity, the new camera doubles Hubble's field of view and expands its capabilities significantly. Upgrading the telescope with ACS's cutting-edge technology made it ten times more effective and prolonged its useful life.

ACS is actually a team of three different cameras: the wide field camera, the high-resolution camera, and the solar blind camera. It outperforms all previous instruments flown aboard the Hubble Space Telescope, primarily because of its expanded wavelength range. Designed to study some of the earliest activity in the universe, ACS sees in wavelengths ranging from far ultraviolet to infrared.

ACS maps the distribution of dark matter, detects the most distant objects in the universe, searches for massive planets, and studies the evolution of clusters of galaxies. To accommodate these science goals, each of ACS's three cameras was designed to perform a specific function. With a field of view twice that of WFPC2, ACS's wide field camera conducts broad surveys of the universe. Astronomers use it to study the nature and distribution of galaxies, which reveal clues about how our universe evolved. The high-resolution camera takes extremely detailed pictures of the inner regions of galaxies. It searches neighboring stars for planets and planets-to be, and takes close-up images of the planets in our own solar system. The solar blind camera, which blocks visible light to enhance ultraviolet sensitivity, focuses on hot stars radiating in ultraviolet wavelengths.

ACS was installed during Servicing Mission 3B in March 2002. The new instrument was built between 1996 and 1999 by scientists and engineers at The Johns Hopkins University, Ball Aerospace, the Space Telescope Science Institute, and NASA's Goddard Space Flight Center. (Text adapted from NASA description.)

Near Infrared Camera and Multi-object Spectrometer

One of the Hubble Space Telescope's advanced instruments is referred to as NICMOS. The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is an instrument providing the capability for infrared imaging and spectroscopic observations of astronomical targets.

NICMOS detects light with wavelengths between 800 to 2500 nanometers. These wavelengths are infrared and thus invisible to our human eyes. At left is a typical image taken with NICMOS. It shows a gigantic star cluster in the center of our milky way. NICMOS is the only Hubble instrument which - due to its infrared capabilities - is able to look through the heavy clouds of dust and gas in these central regions.(Images and text from NASA)

Installed on Hubble in February 1997, NICMOS used infrared vision to probe dark, dusty, never-before-seen regions of space with the optical clarity that only Hubble can provide. Its infrared detectors operated at a very cold temperature (minus 351 degrees Fahrenheit, which is minus 213 degrees Celsius or 60 degrees Kelvin). To keep the detectors cold, NICMOS was encased in a thermos- like container filled with solid nitrogen ice. It was expected that the solid nitrogen ice would last approximately four years. However, the ice evaporated about twice as fast as planned and was depleted after only 23 months of NICMOS science operations. In 1999 -- with its supply of ice exhausted -- NICMOS became dormant. Astronauts installed the a new nitrogen cooling system inside Hubble during the fifth and final spacewalk of Servicing Mission 3B on March 8, 2002. On March 18, the NCS was turned on via commands sent from the Space Telescope Operations Control Center at Goddard. It has continued to operate flawlessly ever since. The deep interior of the NICMOS reached the target temperature of 70 degrees Kelvin (minus 333 degrees Fahrenheit) on April 11.