Explorers Program: Difference between revisions

Revision as of 23:09, 18 September 2024

Revision as of 23:30, 18 September 2024

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The [[Interplanetary Monitoring Platform]] (IMP) was launched in 1963 and involved a network of eleven Explorer satellites designed to collect data on space radiation in support of the [[Apollo program]]. The IMP program was a major step forward in spacecraft [[electronics]] design, as it was the first space program to use [[integrated circuit]] (IC) chips and [[MOSFET]]s (MOS transistors).<ref name="Butrica">{{cite book |last1=Butrica |first1=Andrew J. |chapter=Chapter 3: NASA's Role in the Manufacture of Integrated Circuits |editor-last1=Dick |editor-first1=Steven J. |title=Historical Studies in the Societal Impact of Spaceflight |date=2015 |publisher=NASA |isbn=978-1-62683-027-1 |pages=149-250 (237-242) |chapter-url=https://www.nasa.gov/sites/default/files/atoms/files/historical-studies-societal-impact-spaceflight-ebook_tagged.pdf#page=237}} {{PD-notice}}</ref><ref name="nasa">{{cite book |title=Interplanetary Monitoring Platform |date=29 August 1989 |publisher=NASA |pages=1, 11, 134 |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800012928.pdf |access-date=12 August 2019 |last1=Butler |first1=P. M.}} {{PD-notice}}</ref> The IMP-A ([[Explorer 18]]) in 1963 was the first spacecraft to use IC chips, and the IMP-D ([[Explorer 33]]) in 1966 was the first to use MOSFETs.<ref name="Butrica"/>

Over the following two decades, NASA has launched over 50 Explorer missions,<ref name= "nssdc_list"/> some in conjunction to military programs, usually of an exploratory or survey nature or had specific objectives not requiring the capabilities of a major space observatory. Explorer satellites have made many important discoveries on: Earth's [[magnetosphere]] and the shape of its [[Gravitational field|gravity field]]; the [[solar wind]]; properties of [[micrometeoroids]] raining down on the [[Earth]]; ultraviolet, cosmic and X-rays from the [[Solar System]] and beyond; [[Ionosphere|ionospheric physics]]; [[Solar flare|Solar plasma]]; [[solar energetic particles]]; and [[Atmospheric science|atmospheric physics]]. These missions have also investigated air density, radio astronomy, [[geodesy]], and [[gamma-ray astronomy]].{{fact|date=September 2024}}

With decreases in NASA's budget, Explorer missions became infrequent in the early 1980s.{{fact|date=September 2024}}

=== SMEX, MIDEX, and Student Explorer programs ===

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[[File:Thor-Able III Explorer 6.jpg|thumb|right|200px|[[Explorer 6]] on a [[Thor-Able|Thor-Able III]] launch in August 1959]]

[[File:ISEE-C (ISEE 3) in dynamic test chamber.jpg|thumb|200px|right|ISEE-C in a dynamic test chamber, 1978]]

Many missions are proposed, but not selected. For example, in 2011, the Explorers Program received 22 full missions solicitations, 20 Missions of Opportunity, and 8 USPI.<ref>{{cite web|url=http://explorers.larc.nasa.gov/EX/ |title=Science Office for Mission Assessments: Explorer 2011 |website=Explorers.larc.nasa.gov |access-date=2016-02-24}}</ref> <!-- Missions of Opportunity (MO) are small collaborative missions with spacecraft not operated by NASA, such as an additional instrument. Examples of this include [[Astro-H]], [[CINDI]], [[TWINS]], and [[HETE-2]]. -->Sometimes mission are only partially developed but must be stopped for financial, technological, or bureaucratic reasons. Some missions failed upon reaching orbit including WIRE and TERRIERS.{{fact|date=September 2024}}

Examples of missions that were not developed or cancelled were:<ref name=skyrocket/>