In that respect, Hubble is one in a fleet of telescopes across the globe and in space that study the universe, and it often collaborates with these other observatories to make discoveries. 

1. Those collaborations take many forms, from formal agreements to community-wide observations of an event.
2. Hubble observation time is generally proposed and won through the standard Hubble cyclical call for proposals. 
3. Proposals can request observing time on the James Webb Space Telescope, Chandra X-ray Observatory, the Transiting Exoplanet Survey Satellite (TESS), NOIRLab (formerly National Optical-Infrared Astronomy Research Laboratory) telescopes, National Radio Astronomy Observatory (NRAO) facilities, and the European Space Agency’s XMM-Newton, in conjunction with requests for Hubble observations. 
4. Mid-cycle proposals may be submitted at any time, those received prior to a specified deadline receive consideration for execution beginning approximately two months later. 
5. Investigators may also request Director’s Discretionary Time, which is time set aside each cycle to observe scientifically compelling and unexpected phenomenon, or to support long observing programs that create data for the entire community (such as the Hubble Deep Field).
6.  Proposals for such work go to the Director of the Space Telescope Science Institute in Baltimore for selection.