Editing Great Observatories program (section)

== Successors to Great Observatories ==
[[File:Telescope Primary Mirror Sizes Compared (4198-Image).png|thumb|Primary mirror size comparison of Spitzer, Hubble, and [[James Webb Space Telescope|Webb]] telescopes]]

* The [[James Webb Space Telescope]] (JWST) launched in December 2021 and works simultaneously with Hubble.<ref>{{cite web|url=https://jwst.nasa.gov/about.html|title=About the James Webb Space Telescope|work=Goddard Space Flight Center|publisher=NASA|access-date=2018-12-20}} {{PD-notice}}</ref> Its segmented, deployable mirror is over twice as wide as the Hubble's, increasing angular resolution noticeably, and sensitivity dramatically. Unlike Hubble, JWST observes in the infrared, in order to penetrate dust at cosmological distances. This means it continues some Spitzer capabilities, while some Hubble capabilities are lost in the visible and especially the ultraviolet wavelengths. JWST exceeds Spitzer's performance in near-infrared. The [[European Space Agency|European Space Agency's]] [[Herschel Space Observatory]], operational from 2009 to 2013, has exceeded Spitzer in the far-infrared. The SOFIA ([[Stratospheric Observatory for Infrared Astronomy]]) airborne platform observed in near- and mid-infrared. SOFIA had a larger aperture than Spitzer, but lower relative sensitivity.
* The [[Fermi Gamma-ray Space Telescope]] (FGRST), formerly known as the Gamma Ray Large Area Space Telescope, is a follow-on to Compton launched on 11 June 2008.<ref>{{cite web |url=http://www.nasa.gov/missions/highlights/schedule.html|title=NASA's Shuttle and Rocket Missions — Launch Schedule|publisher=NASA|date=2008-06-05}} {{PD-notice}}</ref> FGRST is more narrowly defined, and much smaller; it carries only one main instrument and a secondary experiment, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). FGRST is complemented by [[Swift Gamma-Ray Burst Mission|Swift]], launched in 2004, and previously by [[HETE 2|HETE-2]], launched in 2000. 
* The [[Reuven Ramaty High Energy Solar Spectroscopic Imager]] (RHESSI), observed in some Compton and Chandra wavelengths between its February 2002 launch and April 2023 decommissioning. RHESSI was pointed at the [[Sun]] at all times, but it occasionally observed high-energy objects in its peripheral view.
*  Another large, high-energy observatory is [[INTEGRAL]], Europe's INTErnational Gamma Ray Astrophysics Laboratory, launched in 2002. It observes in similar frequencies to Compton. INTEGRAL uses a fundamentally different telescope technology, coded-aperture masks. Thus, its capabilities are complementary to Compton and Fermi.