Cold War: <a href="https://en.wikipedia.org/wiki/Space_Race" id="mwAQI" rel="mw:WikiLink" title="Space Race">Space Race</a>: The <a href="https://en.wikipedia.org/wiki/Explorer_1" id="mwAQM" rel="mw:WikiLink" title="Explorer 1">first successful American satellite</a> detects the <a href="https://en.wikipedia.org/wiki/Van_Allen_radiation_belt" id="mwAQQ" rel="mw:WikiLink" title="Van Allen radiation belt">Van Allen radiation belt</a>.