Wide Field Camera 3

Wide Field Camera 3
Name	Wide Field Camera 3
Operator	National Aeronautics and Space Administration (NASA)
Spacecraft	Hubble Space Telescope
Launched	1990 (Hubble) / installed 2009 (STS-125)
Mission type	Space telescope instrument
Manufacturer	Ball Aerospace / NASA Goddard Space Flight Center
Wavelength	Ultraviolet, visible, near-infrared

Wide Field Camera 3 is a scientific imaging instrument installed on the Hubble Space Telescope during the STS-125 servicing mission in 2009. Developed by teams at Ball Aerospace and NASA Goddard Space Flight Center, it extended Hubble's sensitivity across ultraviolet, optical, and near-infrared bands, enabling studies that connect the legacies of Hubble Space Telescope instruments such as the Wide Field and Planetary Camera 2 and the Advanced Camera for Surveys. Funded and managed by NASA in collaboration with partners including the Space Telescope Science Institute, it has become central to programs led by investigators from institutions like Harvard University, California Institute of Technology, and European Space Agency partners.

Overview

Wide Field Camera 3 provides high-resolution, wide-field imaging for the Hubble Space Telescope in three primary regimes: ultraviolet (UV), optical, and near-infrared (NIR). It was delivered to orbit aboard STS-125, replacing the failed Wide Field and Planetary Camera 2 to restore and expand Hubble's survey and follow-up capabilities. As a facility-class instrument it serves observing programs from General Observer proposals, Treasury programs, and Director's Discretionary initiatives coordinated by the Space Telescope Science Institute and supported by teams at NASA Goddard Space Flight Center and international collaborators including European Space Agency scientists.

Design and instrumentation

WFC3 consists of two independent channels: a UV/visible channel and a near-infrared channel, built by industrial teams at Ball Aerospace with detector contributions from organizations such as the Teledyne Imaging Sensors group. The UV/visible channel uses a set of CCD detectors optimized for throughput and radiation tolerance, fed by a filter wheel with broad-, medium-, and narrow-band filters, and supported by calibration lamps and optics designed at NASA Goddard Space Flight Center. The NIR channel employs a mercury cadmium telluride (HgCdTe) detector array cooled passively, with cryogenic heritage traceable to programs at Jet Propulsion Laboratory and detector fabrication partnerships involving Lockheed Martin subcontractors. Optical elements, baffling, and stray-light control were developed with input from teams at University of Arizona and University of California, Berkeley, while system-level verification involved testing at facilities including the Goddard Environmental Test Facility.

Installation and operation aboard Hubble

WFC3 was installed during the STS-125 mission executed by NASA's Space Shuttle program; astronauts operating from Space Shuttle Atlantis performed the replacement during a series of spacewalks planned with support from Johnson Space Center. After mechanical integration into the Hubble Space Telescope payload bay interface and electrical checkout with the spacecraft avionics, WFC3 underwent on-orbit activation and commissioning coordinated by teams at Space Telescope Science Institute and NASA Goddard Space Flight Center. Routine operations are scheduled through the Hubble Space Telescope mission planning system, with observing proposals adjudicated by panels comprising members from organizations like European Space Agency, National Science Foundation, and major research universities. Maintenance tasks, anomaly resolution, and firmware updates have been managed through telecommands from Goddard Space Flight Center with science verification campaigns led by principal investigators at institutions such as Johns Hopkins University.

Scientific capabilities and observing modes

WFC3 supports a range of modes: direct imaging across UV, optical, and NIR bands; slitless spectroscopy using grisms in the NIR and UVIS channels; coronagraphic-style high-contrast imaging via specially designed masks; and time-series photometry for variable and transient sources. Its filter complement enables studies comparable to surveys by facilities like Sloan Digital Sky Survey in optical and probes complementary to the Spitzer Space Telescope and Chandra X-ray Observatory at other wavelengths. The NIR grism modes have been used for spectral surveys akin to programs on James Webb Space Telescope precursor planning, while UV capabilities enabled investigations of sources previously studied with instruments on Galaxy Evolution Explorer and ground-based observatories such as Keck Observatory and Very Large Telescope.

Key discoveries and scientific impact

WFC3 has driven breakthroughs across cosmology, galaxy evolution, star formation, and exoplanet science. It played a pivotal role in precise measurements of high-redshift galaxy luminosity functions and the search for galaxies in the reionization epoch, building on work from teams affiliated with Harvard University, California Institute of Technology, and University of California, Santa Cruz. WFC3 imaging contributed to improved constraints on the Hubble constant when combined with distance-ladder studies involving Hubble Space Telescope Cepheid observations, supernova programs linked to Supernova Cosmology Project collaborators, and calibrations using Gaia parallaxes. In stellar astrophysics, WFC3 enabled resolved-population studies in Local Group systems such as Andromeda Galaxy, Magellanic Clouds, and dwarf galaxies characterized by researchers at University of Cambridge and Max Planck Institute for Astronomy. Its NIR slitless spectroscopy informed surveys of star-forming galaxies overlapping legacy programs from Sloan Digital Sky Survey and deep-field initiatives led by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey teams.

Calibration, data processing, and performance monitoring

Calibration of WFC3 data is performed through pipelines maintained by the Space Telescope Science Institute in coordination with instrument scientists at NASA Goddard Space Flight Center. The calibration reference files and dark, flat, and bias corrections evolve based on on-orbit monitoring programs and calibration observations executed during Hubble cycles, with community access via the Mikulski Archive for Space Telescopes. Performance monitoring addresses detector effects such as charge transfer inefficiency in CCDs and persistence in NIR arrays, leveraging analyses by teams at European Space Agency centers, Johns Hopkins University, and national laboratories. Data reduction workflows integrate software maintained by the Space Telescope Science Institute and community tools used by groups at University of California, Santa Cruz, University of Michigan, and international partners, ensuring WFC3 products support proposals across cosmology, stellar populations, and exoplanet research.

Category:Space telescopes Category:Hubble Space Telescope instruments