A good source to search for satellites, instruments and requirements of application areas is the Observing Systems Capability Analysis and Review Tool (OSCAR) by the World Meteorological Organization (WMO).
- To search for satellites: https://space.oscar.wmo.int/satellites
- To search for instruments: https://space.oscar.wmo.int/instruments
- You may also use the capabilities review to find appropriate instruments for a study, or the gap analyses tab to find appropriate future instruments.
You may also try the CEOS database, e.g. https://database.eohandbook.com/database/missiontable.aspx or its homepage.