Editing Explorers Program (section)

{{Short description|Ongoing NASA space exploration program}}
{{Use American English|date=October 2021}}
{{Use dmy dates|date=October 2021}}

[[File:Pointing X-ray Eyes at our Resident Supermassive Black Hole.jpg|thumb|upright=1.0|right|An Explorer mission observes [[Sagittarius A*]], the [[Milky Way|Milky Way's]] central [[black hole]], flaring.]]

The '''Explorers Program'''<ref>{{cite web |title=Explorers Program |url=https://explorers.gsfc.nasa.gov/ |website=Explorers Program Home Page at NASA Goddard |publisher=NASA |access-date=3 May 2022}} {{PD-notice}}</ref> is a [[NASA]] exploration program that provides flight opportunities for physics, [[geophysics]], [[heliophysics]], and [[astrophysics]] investigations from space. Launched in 1958, [[Explorer 1]] was the first spacecraft of the United States to achieve orbit. Over 90 space missions have been launched since. Starting with [[Explorer 6]], it has been operated by NASA, with regular collaboration with a variety of other institutions, including many international partners.

Launchers for the Explorers Program have included [[Juno I]], [[Juno II]], various [[Thor (rocket family)|Thor]], [[Scout (rocket family)|Scout]], [[Delta (rocket family)|Delta]] and [[Northrop Grumman Pegasus|Pegasus]] launch vehicles, and [[Falcon 9]].

The program has three classes: Medium-Class Explorers (MIDEX), Small Explorers (SMEX), and University-Class Explorers (UNEX), with select Missions of Opportunity operated with other agencies.