NASA Selects Proposals to Study Sun, Space Environment

NASA has selected nine proposals under its Explorers Program that
will return transformational science about the Sun and space
environment and fill science gaps between the agency’s larger
missions; eight for focused scientific investigations and one
for technological development of instrumentation. One, called
Sun Radio Interferometer Space Experiment (SunRISE), is managed
by NASA’s Jet Propulsion Laboratory, Pasadena, California.

The broad scope of the investigations illustrates the many
vital and specialized research areas that must be explored
simultaneously in the area of heliophysics, which
is the study of how the Sun affects space and the space
environment of planets.

“The Explorers Program seeks innovative ideas for small and
cost-constrained missions that can help unravel the mysteries
of the Universe,” said Paul Hertz, director of NASA’s Astrophysics
Division and the selection official. “These missions absolutely
meet that standard with proposals to solve mysteries about the
Sun’s corona, the Earth’s atmosphere and magnetosphere, and the
solar wind.”

Under the selected proposals, five Heliophysics Small Explorer
missions and two Explorer Missions of Opportunity Small
Complete Missions (SCM), concept studies will be conducted that
span a broad range of investigations focusing on terrestrial
weather in the near-Earth space environment — magnetic energy,
solar wind, heating and energy released in the solar

The proposals were selected based on potential science value
and feasibility of development plans. Small Explorer mission
costs are capped at $165 million each, and Mission of
Opportunity costs are capped at $55 million each.

Each Heliophysics Small Explorer mission will receive $1.25
million to conduct an 11-month mission concept study. The
selected proposals are:

Mechanisms of Energetic Mass Ejection — eXplorer

  • MEME-X will map the universal physical processes of the
    lower geospace system that control the mass flux through the
    upper atmosphere to space potentially transforming our
    understanding of how ions leave Earth’s atmosphere.
  • Principal investigator: Thomas Moore at NASA’s Goddard
    Space Flight Center in Greenbelt, Maryland

Focusing Optics X-ray Solar Imager (FOXSI)

  • FOXSI is a solar-dedicated, direct-imaging, Hard X-Ray
    telescope that would detect hot plasma and energetic electrons
    in and near energy release sites in the solar corona.
  • Principal investigator: Steven Christe at Goddard

Multi-Slit Solar Explorer (MUSE)

  • MUSE will provide data to advance understanding of the
    difficult problems of mechanisms responsible for energy release
    in the corona and the dynamics of the solar atmosphere.
  • Principal investigator: Ted Tarbell at Lockheed Martin Inc.
    in Palo Alto, California

Tandem Reconnection and Cusp Electrodynamics
Reconnaissance Satellites (TRACERS)

  • TRACERS will fill a fundamental gap in our knowledge of the
    global variability in magnetopause reconnection by providing an
    abundant, well targeted set of new and unique in situ
  • Principal investigator: Craig Kletzing at the University of
    Iowa, in Iowa City

Polarimeter to Unify the Corona and Heliosphere

  • PUNCH will advance our understanding of how coronal
    structures fuel the ambient solar wind with mass and energy,
    and the dynamic evolution of transient structures in the young
    solar wind (near the source surface).
  • Principal investigator: Craig DeForest at Southwest
    Research Institute in Boulder, Colorado

Each Mission of Opportunity SCM will receive $400,000 to
conduct an 11-month mission concept study. The selected
proposals are:

Sun Radio Interferometer Space Experiment

  • SunRISE will consist of a constellation of cubesats
    operating as a synthetic aperture radio telescope to address
    the critical heliophysics problems of how solar energetic
    particles are accelerated and released into interplanetary
  • Principal investigator: Justin Kasper at the University of
    Michigan in Ann Arbor

Atmospheric Waves Experiment (AWE)

  • AWE will investigate how atmospheric gravity waves,
    including those generated by terrestrial weather, impact the
    transport of energy and momentum from the lower atmosphere into
    near-Earth space, a fundamental question in Heliophysics.
  • Principal investigator: Michael Taylor at Utah State
    University Research Foundation in Logan

A Partner Mission of Opportunity (PMO) proposal has been
selected for components and scientific analysis for three in
situ payload instruments aboard the Turbulence Heating ObserveR
(THOR) mission – one of four proposed missions currently under
consideration by ESA (European Space Agency). After ESA’s final
selection, work will begin on implementation of the PMO only if
THOR is selected.

The chosen PMO is:

U.S. Contributions to the THOR mission

  • THOR-US will provide components and scientific analysis for
    an investigation into how plasma is heated and accelerated by
    the dissipation of turbulent fluctuations through kinetic
    processes. The concept study for THOR-US was conducted prior to
    its selection for NASA’s Explorer Program, so the team is
    positioned to move into the detailed design phase if its host
    mission is selected.
  • Principal investigator: Harald Kucharek at University of
    New Hampshire in Durham

One Mission of Opportunity SCM received highly favorable review
for scientific and scientific implementation merit, but was
deemed to require more technological development of the
instrument’s innovative optical design before further
consideration of an implementation concept. This proposal is
offered funding for a continued technology development study.
The SCM chosen for a technology development investigation is:

COronal Spectrographic Imager in the Extreme
ultraviolet (COSIE)

  • COSIE would provide a missing link between the physics of
    the low corona and that of the heliosphere with a unique and
    innovative instrument based on the International Space Station.
  • Principal investigator: Leon Golub at the Smithsonian
    Institution/Smithsonian Astrophysical Observatory in Cambridge,

The Explorers Program is the oldest continuous NASA program
designed to provide frequent, low-cost access to space using
principal investigator-led space science investigations
relevant to the agency’s astrophysics and heliophysics
programs. Since the Explorer 1 launch in 1958, which discovered
Earth’s radiation belts, the Explorers Program has launched
more than 90 missions, including the
and Cosmic Background
Explorer (COBE)
missions that led to Nobel Prizes for their

The program is managed by Goddard for NASA’s Science Mission
Directorate in Washington, which conducts a wide variety of
research and scientific exploration programs for Earth studies,
space weather, the solar system and universe.

For more information about NASA’s Science Mission Directorate
activities, visit:

News Media Contact

Dwayne Brown
NASA Headquarters, Washington

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.