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Hubble has had 4 servicing missions, each of which cost an entire shuttle launch. Hubble is extremely expensive to service -- and it's currently running with tw

Hubble has had 4 servicing missions, each of which cost an entire shuttle launch. Hubble is extremely expensive to service -- and it's currently running with two broken gyroscopes, since there's no shuttle to service it and nobody has the budget to do a SpaceX launch to fix it when it's "working fine". JWST, its replacement, has been in a warehouse for thirty years. "In space" doesn't fix any of the problems!

privong 6y ago
> JWST, its replacement, has been in a warehouse for thirty years JWST development was started in 1996 (25 years ago), so it can't have been in a warehouse for 30 years. The detailed design phase was ongoing in 2007 and assembly of the primary mirror was only completed in 2016 (dates from https://en.wikipedia.org/wiki/James_Webb_Space_Telescope https://en.wikipedia.org/wiki/James_Webb_Space_Telescope). Perhaps you're thinking of the National Reconnaissance Office telescopes that were offered to NASA in 2012 (https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...)? Those are similar telescopes to Hubble in some ways, and one is being used for the WFIRST mission. Despite sometimes being billed as such, JWST can only be partly considered a replacement for HST. HST has ultraviolet observing capabilities (wavelengths a short as ~90nm), while JWST observes primarily in the infrared, with some capability to wavelengths of 600nm. There's some overlap (in the 600nm-1600nm range), but JWST can observe out to about 28,000nm (28micron) wavelengths. The JWST wavelength range is perhaps more comparable to that of the Spitzer Space Telescope (particularly the IRAC and IRS instruments, covering 3.5-40microns; MIPS covered out to 160microns). The LUVOIR concept (https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...) would probably have the better claim to being an HST successor, given its proposed UV capabilities.

privong 6y ago

> JWST, its replacement, has been in a warehouse for thirty years JWST development was started in 1996 (25 years ago), so it can't have been in a warehouse for 30 years. The detailed design phase was ongoing in 2007 and assembly of the primary mirror was only completed in 2016 (dates from https://en.wikipedia.org/wiki/James_Webb_Space_Telescope https://en.wikipedia.org/wiki/James_Webb_Space_Telescope). Perhaps you're thinking of the National Reconnaissance Office telescopes that were offered to NASA in 2012 (https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...)? Those are similar telescopes to Hubble in some ways, and one is being used for the WFIRST mission. Despite sometimes being billed as such, JWST can only be partly considered a replacement for HST. HST has ultraviolet observing capabilities (wavelengths a short as ~90nm), while JWST observes primarily in the infrared, with some capability to wavelengths of 600nm. There's some overlap (in the 600nm-1600nm range), but JWST can observe out to about 28,000nm (28micron) wavelengths. The JWST wavelength range is perhaps more comparable to that of the Spitzer Space Telescope (particularly the IRAC and IRS instruments, covering 3.5-40microns; MIPS covered out to 160microns). The LUVOIR concept (https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...) would probably have the better claim to being an HST successor, given its proposed UV capabilities.