WASHINGTON — NASA approved the Ionospheric Connection Explorer (ICON), a small heliophysics mission set to launch no later than October 2017, to proceed into development, the agency announced Nov. 12.

ICON, selected as a heliophysics explorer mission last year , will spend its two-year primary mission studying the ionosphere: a region of space ranging from about 90 kilometers to 900 kilometers above Earth’s surface and filled with electrically charged particles that can disrupt radio signals from satellites. The mission’s principal investigator is Thomas Immel of the University of California, Berkeley.

Development costs for ICON, which exclude launch and operations, are capped at $200 million. The mission will be built on Orbital Sciences Corp.’s LEOStar-2 spacecraft bus, a platform designed to last at least five years and that has been the basis of numerous NASA science spacecraft.

Construction on ICON would begin in 2015, when ICON is slated for its critical design review.

ICON’s four instruments, and the institutions providing them, are:

A pair of ultraviolet imaging spectrographs, one tuned to the extreme ultraviolet portion of the spectrum and the other to the far ultraviolet, provided by the University of California, Berkeley’s Space Sciences Laboratory.

The Michelson Interferometer for Global High-Resolution Thermospheric Imaging, provided by the Naval Research Laboratory in Washington, which will observe the temperature and speed of the neutral particles in the ionosphere.

An Ion Velocity Meter provided by the University of Texas in Dallas that will observe the speed of charged particle motions, which NASA said may be “very different” from neutral ionospheric gas.

ICON is the second small science satellite NASA has approved for development in as many weeks. On Nov. 7, the agency said the Transiting Exoplanet Survey Satellite (TESS), also being built by Orbital on a LEOStar-2 bus, passed its confirmation review and would begin development with an eye toward a 2017 launch.

NASA’s Launch Services Division will arrange a launch for both TESS, which needs a medium-class launcher such as Space Exploration Technologies Corp.’s Falcon 9, and ICON, which needs a small-class launcher.

That makes ICON a potential candidate to launch aboard Orbital’s reliable but dormant Pegasus XL: a solid rocket air-launched from a modified Lockheed L-1011 TriStar jet. The only other small-class launchers on NASA’s Launch Services 2 contract, the catalog from which the agency orders rockets for its science missions, are Lockheed Martin’s Athena 1c and Orbital’s Minotaur-C. The last Athena launch was in 2001. Minotaur-C is essentially Orbital’s Taurus XL solid rocket with a different payload fairing than the one that failed to separate in back-to-back missions in 2009 and 2011, destroying NASA’s Orbiting Carbon Observatory and Glory satellites.

Pegasus XL last flew in June 2013, when it launched NASA’s Interface Region Imaging Spectrograph spacecraft. NASA paid about $40 million for that launch, which was the 42nd Pegasus launch.