The James Webb Space Telescope (JWST) and the Hubble Space Telescope (HST) are two of NASA's most significant astronomical observatories, but they differ in several key ways:
Wavelength Range:
Hubble:Hubble primarily observes in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum.
JWST: JWST is designed to observe in the mid-infrared and near-infrared regions of the spectrum. It is optimized for detecting infrared radiation.
Size and Weight:
Hubble: The HST is significantly smaller and lighter than the JWST. It has a 2.4-meter primary mirror and weighs about 11 tons.
JWST: JWST is much larger and heavier, with a 6.5-meter primary mirror and a total mass of approximately 6.5 tons. It had to be folded for launch aboard an Ariane 5 rocket.
Orbit:
Hubble: Hubble orbits Earth at an altitude of about 550 kilometers (340 miles). It is in low Earth orbit.
JWST: JWST is positioned at the second Lagrange point (L2), which is located about 1.5 million kilometers (approximately 930,000 miles) from Earth. This location provides a stable and clear view of the universe.
Instruments:
Hubble: Hubble is equipped with a range of scientific instruments that can observe in various wavelengths, including cameras, spectrographs, and detectors.
JWST: JWST has four primary scientific instruments, each specialized for infrared observations. These instruments are the Near Infrared Camera (NIRCam), Near Infrared Spectrograph (NIRSpec), Mid-Infrared Instrument (MIRI), and Near Infrared Imager and Slitless Spectrograph (NIRISS).
Observational Goals:
JWST: JWST is primarily designed to study the early universe, the formation and evolution of stars and galaxies, and the atmospheres of exoplanets. Its infrared capabilities make it particularly suited for probing objects and phenomena that emit predominantly in the infrared part of the spectrum.
Operational Lifespan:
Hubble: Hubble was launched in 1990 and has undergone several servicing missions to extend its operational life. It continues to operate as of my last knowledge update in September 2021.
JWST: JWST is designed for a planned operational lifespan of at least 10 years, with the possibility of extensions. It is set to be launched in late 2021 (or beyond, depending on updates).
In summary, the Hubble Space Telescope and the James Webb Space Telescope are both powerful observatories, but they have distinct differences in terms of their size, wavelength range, orbital positions, and scientific objectives. JWST's specialization in infrared observations opens up new possibilities for studying the universe, complementing and extending the capabilities of Hubble.