Frequently Asked Questions (FAQs)

The James Webb Space Telescope, also called Webb or JWST, is a large, space-based observatory, optimized for infrared wavelengths, which will complement and extend the discoveries of the Hubble Space Telescope. It will have longer wavelength coverage and greatly improved sensitivity. The longer wavelengths enable Webb to look further back in time to find the first galaxies that formed in the early Universe, and to peer inside dust clouds where stars and planetary systems are forming today (Source: external pageNASAcall_made).

The reason for JWST’s cryogenic temperature is that it observes the infrared range of the electro-magnetic spectrum. Any objects at ambient temperatures emits infrared light due to its black-body emission. If an observatory like JWST would be operated at ambient temperatures, its self emission would overexpose the faint light from the astronomical source. Therefore, any astronomical instrument for infrared is cooled to cryogenic temperatures.  

This space-based observatory is named after James E. Webb (1906- 1992), NASA's second administrator. Webb is best known for leading Apollo, a series of lunar exploration programs that landed the first humans on the Moon. However, he also initiated a vigorous space science program that was responsible for more than 75 launches during his tenure, including America's first interplanetary explorers. James E. Webb's official NASA biography can be found external pageherecall_made (Source: external pageNASAcall_made).

Webb is designed to have a mission lifetime of not less than 5-1/2 years after launch, with the goal of having a lifetime greater than 10 years. The lifetime is ultimately limited by the amount of fuel used for maintaining the orbit, and by proper functioning in orbit of the spacecraft and instruments. Webb will carry fuel for a 10-year lifetime (with margin); the project will perform mission assurance testing of the flight system to guarantee 5 years of scientific operations starting at the end of the commissioning period 6 months after launch (Source: external pageNASAcall_made).

The NASA cost to build, launch and commission the observatory is $8.8 Billion (approx. CHF 795 Million). Five years of operations $860 Million (approx. CHF 795 Million), for a total lifecycle cost of $9.66 Billion (approx. CHF 8.9 Billion). It should be noted that the facility is not necessarily limited to 5 years of operations, but that is the top level mission requirement. The observatory will contain sufficient consumables to operate for approximately 10 years (Source: external pageNASAcall_made).