Explorers Program

The Explorers Program is a <a href="/facts/NASA/TIMCV0yV">NASA</a> exploration program that provides flight opportunities for physics, <a href="/facts/Geophysics/ywVQ1sAQ">geophysics</a>, <a href="/facts/Heliophysics/QW7vrybp">heliophysics</a>, and <a href="/facts/Astrophysics/krFPRWLA">astrophysics</a> investigations from space. Launched in 1958, <a href="/facts/Explorer_1/m4jWb1A0">Explorer 1</a> was the first spacecraft of the United States to achieve orbit. Over 90 space missions have been launched since. Starting with <a href="/facts/Explorer_6/3PYELsuV">Explorer 6</a>, 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 <a href="/facts/Juno_I/kIjnSPvX">Juno I</a>, <a href="/facts/Juno_II/L44wwv2U">Juno II</a>, various <a href="/facts/Thor_(rocket_family)/mbFIsEct">Thor</a>, <a href="/facts/Scout_(rocket_family)/y3J3BcVd">Scout</a>, <a href="/facts/Delta_(rocket_family)/gQH4EUYB">Delta</a> and <a href="/facts/Northrop_Grumman_Pegasus/w8swDwhu">Pegasus</a> launch vehicles, and <a href="/facts/Falcon_9/mNck6vby">Falcon 9</a>.
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.

Explorers Program open-in-new

Explorers Program