The Small Explorer program (SMEX) is an effort within NASA to fund space exploration missions that cost no more than US$120 million.[1] Extending the larger Explorers program, it was started in 1989.[2]

Program history

The first set of three SMEX missions were launched between 1992 and 1998. The second set of two missions were launched in 1998 and 1999. These missions were managed by the Small Explorer Project Office at NASA's Goddard Space Flight Center (GSFC). In early 1999, that office was closed and with the announcement of opportunity for the third set of SMEX missions NASA converted the program so that each mission was managed by its Principal Investigator, with oversight by the GSFC Explorers Project.[3]

As of 2017, NASA is funding a competitive study of five candidate heliophysics Small Explorers missions, with the expectation that one finalist proposal will be selected as a mission for flight in 2022. The proposals are Mechanisms of Energetic Mass Ejection – eXplorer (MEME-X), Focusing Optics X-ray Solar Imager (FOXSI), Multi-Slit Solar Explorer (MUSE), Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS), and Polarimeter to Unify the Corona and Heliosphere (PUNCH).[4][5][6]

List of missions

Launch (UTC) Status
SAMPEX SMEX-1 Explorer-68 3 July 1992 Ended: 30 June 2004
Reentered: 13 November 2012
TOMS-EP 2 July 1996 Single instrument: Total Ozone Mapping Spectrometer 3.[7]
FAST SMEX-2 Explorer-70 21 August 1996 Ended: 4 May 2009
SWAS SMEX-3 Explorer-74 6 December 1998 Ended: 21 July 2004
TRACE SMEX-4 Explorer-73 2 April 1998 Ended: 21 June 2010
WIRE SMEX-5 Explorer-75 5 March 1999 Spacecraft equipment failure
Reentered: 10 May 2011
RHESSI SMEX-6 Explorer-81 5 February 2002 Ended: April 2018
Decommissioned: 16 August 2018
GALEX SMEX-7 Explorer-83 28 April 2003 Ended: May 2012
Decommissioned: 28 June 2013
Cancelled, instrument not sensitive as expected
AIM SMEX-9 Explorer-90 25 April 2007 Operational
IBEX SMEX-10 Explorer-91 19 October 2008 Operational
NuSTAR SMEX-11 Explorer-93 13 June 2012 Operational
IRIS SMEX-12 Explorer-94 28 June 2013 Operational
Cancelled, expected cost overrun
IXPE SMEX-14 TBD 2021[8] In development

See also


  1. ^ "Explorers Missions". NASA. Archived from the original on 23 March 2010. Retrieved 28 August 2015.
  2. ^ Mason, G. M.; Baker, D. N.; Blake, J. B.; Boughner, R. E.; Callis, L. B.; et al. (1998). SAMPEX: NASA's First Small Explorer Satellite. IEEE Aerospace Conference. 21–28 March 1998. Aspen, Colorado. 5. pp. 389–412. doi:10.1109/AERO.1998.685848.
  3. ^ "Welcome to the Small Explorer's Web Site". NASA. 18 February 2000. Archived from the original on 17 August 2000.
  4. ^ Brown, Dwayne (28 July 2017). "NASA Selects Proposals to Study Sun, Space Environment". NASA. Retrieved 7 December 2017.
  5. ^ "Announcement of Opportunity: Heliophysics Explorers Program, 2016 Small Explorer (SMEX)" (PDF). NASA. 13 July 2016. NNH16ZDA005O.
  6. ^ Mendoza-Hill, Alicia (25 August 2017). "Heliophysics Small Explorers 2016 Announcement of Opportunity: Concept Study Report Kickoff" (PDF). NASA / Launch Services Program.
  7. ^ "NASA - NSSDCA - Spacecraft - Details". 2017-03-21. Retrieved 2018-04-20.
  8. ^ Soffitta, Paolo (2017). IXPE the Imaging X-ray Polarimetry Explorer. UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XX. Bibcode:2017SPIE10397E..0IS. doi:10.1117/12.2275485. 103970I.

External links