Over the years, NASA has launched a series of “Explorer” spacecraft carrying a wide variety of scientific investigations. It is not only the longest running series of spacecraft, but has produced highly-durable (i.e., well-engineered) spacecraft as well.
Operational Missions — ACE | RXTE (XTE)
Past Missions — IMP-8
Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $180 million total cost to NASA.
Operational Missions — WISE | THEMIS | Swift
Past Missions — WMAP (MAP) | IMAGE | FUSE
Explorer (EX) missions are introduced with the Announcement of Opportunity, Explorers 2011 for new missions. EX missions were conceived in response to the current available expendable launch vehicles. EX missions fall between the previous Small Explorer (SMEX) and Medium Explorer (MIDEX) classes. Access to space utilizes one of the several, lower-cost expandable launch vehicles available through NASA's launch services program.
Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $120 million total cost to NASA.
Missions in Development — GEMS | IRIS | NuSTAR
Operational Missions — IBEX | AIM | GALEX | RHESSI (HESSI)
Past Missions — SWAS | TRACE | FAST | SAMPEX
Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $15.0M (real year dollars) total cost to NASA. UNEX missions will be launched by a variety of low cost methods
Investigations characterized by being part of a non-NASA space mission of any size and having a total NASA cost of under $35 million. These missions are conducted on a no-exchange-of-funds basis with the organization sponsoring the mission. NASA intends to solicit proposals for Missions of Opportunity with each Announcement of Opportunity (AO) issued for UNEX, SMEX, and MIDEX investigations.
Missions in Development — Astro-H
Operational Missions — CINDI | TWINS
Past Missions — HETE-2
Operational Missions — INTEGRAL
