Planned development of space-based observatories in the next 15 years, as planned out currently:
Operational: HST (NASA, LEO), GAIA (ESA, SEL2), SWIFT (NASA, LEO)
2016 - ASTRO-H online (JAXA, SSO), HXMT online (CNSA, SSO)
2017 - CHEOPS online (ESA, SEL2), TESS online (NASA, HEO)
2018 - JWST online (NASA/ESA, SEL2)
2019 - ASTRO-H offline (JAXA, SSO), GAIA offline (ESA, SEL2), TESS offline (NASA, HEO)
2020 - EUCLID online (ESA, SEL2), HXMT offline (CNSA, SSO), HSToffline (NASA, LEO)
2021 - SVOM online (CNSA, SSO)
2022 - CHEOPS offline (ESA, SEL2)
2023 -
2024 - WFIRST online (NASA, GEO), PLATO online (ESA, SEL2), SVOM offline (CNSA, SSO)
2025 - ATLAST possible (NASA, SEL2), EUCLID offline (ESA, SEL2), CV M4 possible* (ESA, SEL2)
2026 -
2027 -
2028 -
2029 -
2030 - WFIRST offline (NASA, GEO), PLATO offline (ESA, SEL2)
* M4 candidates: 66% chance for ARIEL or XIPE observatories
Notes:
Not counting NANO-JASMINE given its likely rather short time of operation.
Not putting SWIFT offline date in there since it could fail at any time. Since 2010 or so.
Not putting any ISS-based missions in there (e.g. EUSO, NICER, CREAM, MAXI).
Not putting any Russian missions in there due to unreliability of funding (e.g. SPEKTR-RG, SPEKTR-UV).
(copying over from a post i made on another forum)