Hubble

Hubble
Name	Hubble Space Telescope
Caption	The Hubble Space Telescope in orbit, as seen from the Space Shuttle Discovery during STS-125.
Mission type	Astronomy
Operator	NASA / ESA / STScI
Launch date	24 April 1990
Launch vehicle	Space Shuttle Discovery (STS-31)
Mission duration	34 years, 1 month, 10 days (ongoing)
Orbit regime	Low Earth orbit
Telescope type	Ritchey–Chrétien telescope
Wavelength	Visible, ultraviolet, near-infrared
Diameter	2.4 m (7 ft 10 in)
Website	https://www.nasa.gov/mission_pages/hubble/main/index.html

Hubble is a large, space-based observatory that has revolutionized astronomy since its launch in 1990. Operating from a low Earth orbit, it provides exceptionally clear images free from the distorting effects of the Earth's atmosphere. The telescope is a flagship project of NASA and the European Space Agency, managed by the Space Telescope Science Institute. Its decades of operation have fundamentally altered our understanding of the universe, from our Solar System to the most distant galaxies.

Overview

The observatory was named in honor of the pioneering American astronomer Edwin Hubble, who provided key evidence for the expansion of the universe. It was designed to be serviced in orbit by astronauts aboard the Space Shuttle, a feature that proved critical to its long-term success. Orbiting at an altitude of approximately 547 kilometers, it completes a circuit around Earth roughly every 95 minutes. Data from its instruments is transmitted via satellite relays to ground stations for analysis by scientists worldwide.

Development and launch

The concept for a large space telescope was vigorously advocated by astronomer Lyman Spitzer starting in the 1940s. Congress approved initial funding in the 1970s, with major contributions from Lockheed Martin and PerkinElmer for the spacecraft and optics. Development was plagued by technical delays and budget overruns, pushing the launch date into the next decade. It was finally deployed into orbit by the crew of STS-31 aboard the Space Shuttle Discovery. However, soon after launch, a flaw in its primary mirror was discovered, causing a severe spherical aberration that initially crippled its imaging capabilities.

Scientific instruments and capabilities

The observatory hosts a suite of instruments that observe in ultraviolet, visible light, and near-infrared wavelengths. Key instruments have included the Wide Field and Planetary Camera, the Space Telescope Imaging Spectrograph, and the Advanced Camera for Surveys. These tools allow for high-resolution imaging, precise photometry, and detailed spectroscopy of astronomical objects. The Fine Guidance Sensors provide exceptional pointing stability and have also been used for astrometry, making precise measurements of stellar positions.

Major discoveries and contributions

It has made countless transformative observations, providing deep views of the universe like the iconic Hubble Deep Field. Its data helped precisely measure the rate of the universe's expansion, constraining the value of the Hubble constant and providing evidence for dark energy. The telescope has directly imaged protoplanetary disks in the Orion Nebula, studied the atmospheric composition of extrasolar planets, and monitored dynamic weather on bodies within our Solar System like Jupiter and Mars. Observations of supernovae in distant galaxies were pivotal to modern cosmology.

Servicing missions and upgrades

A series of Space Shuttle missions were conducted to repair, maintain, and upgrade the observatory. The first, STS-61 in 1993, installed corrective optics, effectively giving the telescope "glasses" to fix its blurry vision. Subsequent missions, including STS-82, STS-103, STS-109, and the final servicing mission STS-125, replaced aging components like gyroscopes and batteries, and installed new, more powerful scientific instruments. These servicing missions, carried out by astronauts from NASA and involving complex extravehicular activity, extended its operational life far beyond original expectations.

Legacy and future of space telescopes

It has become a cultural icon, with its stunning images featured everywhere from textbooks to popular media, profoundly impacting public engagement with science. Its success paved the way for a new generation of space observatories. The James Webb Space Telescope, launched in 2021, is designed as a successor, observing primarily in the infrared to peer further back in time. Other future missions, like the Nancy Grace Roman Space Telescope and the ESA's Euclid, will build upon its legacy to explore dark matter, dark energy, and the cosmic web.

Category:Space telescopes Category:NASA spacecraft Category:1990 in spaceflight