In contrast to other proposed observatories, the JWST telescope is the last big NASA astrophysics mission of its generation to be built. The James Webb Space Telescope, previously known as Next Generation Space Telescope, is a space observatory under construction and scheduled to launch in October 2018. The JWST will offer unprecedented resolution and sensitivity from long-wavelength visible to the mid-infrared, and is a successor instrument to the Hubble Space Telescope and the Spitzer Space Telescope. The telescope features a segmented 6.5-meter diameter primary mirror and will be located near the Earth–Sun L2 point. A large sunshield will keep its mirror and four science instruments below 50 K. JWST’s capabilities will enable a broad range of investigations across the fields of astronomy and cosmology.
One particular goal involves observing some of the most distant objects in the Universe, beyond the reach of current ground and space based instruments. This includes the very first stars, the epoch of reionization, and the formation of the first galaxies. Another goal is understanding the formation of stars and planets. This will include imaging molecular clouds and star-forming clusters, studying the debris disks around stars, direct imaging of planets, and spectroscopic examination of planetary transits.
In gestation since 1996, the project represents an international collaboration of about 17 countries led by NASA, and with significant contributions from the European Space Agency and the Canadian Space Agency. It is named after James E. Webb, the second administrator of NASA, who played an integral role in the Apollo program.
The Hubble Space Telescope is a space telescope that was launched into low Earth orbit in 1990, and remains in operation. With a 2.4-meter (7.9 ft) mirror, Hubble’s four main instruments observe in the near ultraviolet, visible, and near infrared spectra. The telescope is named after the astronomer Edwin Hubble.
Hubble’s orbit outside the distortion of Earth’s atmosphere allows it to take extremely high-resolution images with negligible background light. Hubble has recorded some of the most detailed visible-light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.
Hubble’s Impressive Shots
Although not the first space telescope, Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. The HST was built by the United States space agency NASA, with contributions from the European Space Agency, and is operated by the Space Telescope Science Institute. The HST is one of NASA’s Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope.
Hubble is the only telescope designed to be serviced in space by astronauts. After launch by Space Shuttle Discovery in 1990, four subsequent Space Shuttle missions repaired, upgraded, and replaced systems on the telescope.
Space telescopes were proposed as early as 1923. Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, Hubble’s main mirror was found to have been ground incorrectly, compromising the telescope’s capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.