NASA’s Explorers Program Selects Five Proposals to Explore the Cosmos

New programs selected will study neutron star-black hole binary systems, the expansion of space and galaxies in the early cosmos, the star formation cycle of the Milky Way and more

The Nuclear Spectroscopic Telescope Array (NuSTAR), launched in 2012, is an Explorer mission that allows astronomers to study the universe in high energy X-rays. Credits: NASA/JPL-Caltech
The Nuclear Spectroscopic Telescope Array (NuSTAR), launched in 2012, is an Explorer mission that allows astronomers to study the universe in high energy X-rays.
Credits: NASA/JPL-Caltech

Space news (October 29, 2015) – NASA Headquarters, Washington, D.C. –

NASA’s Explorers Program was designed in the spirit of the first explorers who traveled across the deep, dark and mysterious oceans and lands in search of the unknown. Thousands of years ago, archaeologists believe ancient humans used the stars, ocean currents and waves to navigate across the seas to new lands. Today, astronauts and scientists taking part in NASA’s Explorers Program travel across space-time to stellar objects in the sky using scientific instruments and spacecraft ancient humans would perceive as God-like. 

NASA’s Explorers Program began with the launch of the first spacecraft designed by engineers and scientists working for the Army Ballistic Missile Agency on January 31, 1958, making it the oldest continuously running low-cost NASA program in history. Fittingly called “Explorer”, since this first spacecraft over 90 space missions to the stars have been designed and launched as part of the Explorers Program. Space missions to the stars that have made startling discoveries about Earth’s magnetosphere and gravity field, the composition of the solar wind and solar plasma erupting from the surface of the Sun. They have traveled to other planets in the solar system and studied radio and gamma-ray astronomy, and in the future will enable the human journey to the beginning of space and time.

NASA recently announced five less-expensive Explorers Program missions designed to the fill the scientific and technical gaps their more involved and expensive space missions. The selected space missions will examine polarized X-ray emissions emitted by binary star systems composed of a neutron star and black hole and the expansion of spacetime during the early moments of the universe. They’ll also take a closer look at the formation of galaxies during the first moments of the cosmos and the birth and life cycle of stars in the Milky Way.

Located in the Goddard Space Flight Center in Greenbelt, MD, the Explorers Program provides an opportunity for human robotic-envoys to make frequent trips into space for scientific explorations of the solar system and cosmos. Relatively low-cost, small to medium size space missions requiring fewer resources and time compared to larger missions to get off the drawing board and into space.

The Explorers Program brings out some of the most creative ideas for missions to help unravel the mysteries of the Universe,” said John Grunsfeld, NASA’s Associate Administrator for Science at NASA Headquarters, in Washington. “The program has resulted in great missions that have returned transformational science, and these selections promise to continue that tradition.”

Now, each of the three selected Small Explorers mission proposals will receive $1 million to conduct an 11-month mission concept study, while the two Missions of Opportunity proposals receive $250,000 to conduct an 11-month mission implementation concept study. 

During the months ahead, NASA scientists will conduct concept studies and detailed evaluations of each proposal selected. After this, they’ll select one mission of each type to proceed to construction and launch, by 2020 at the earliest. In the end, the total cost for this part of the Explorers Program is capped at just around $190 million for the two missions selected: $125 million for each Small Explorers mission and $65 million for each Mission of Opportunity.

The three Small Explorers Program missions selected are:


SPHEREx explores the origin and evolution of the cosmos and galaxies in the sky and the possibility planets around other stars could harbor life.

James Bock of the California Institute of Technology in Pasadena, California is the main scientist on this mission.

Imaging X-ray Polarimetry Explorer (IXPE)

IXPE studies the processes leading to X-ray emission in neutron stars, pulsar wind nebulae, and stellar and supermassive black holes using X-ray polarimetry, the measurement, and interpretation of the polarization of electromagnetic waves. 

Martin Weisskopf of NASA’s Marshall Space Flight Center in Huntsville, Alabama is the main scientist on this project.

Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS)

PRAXyS uses X-ray polarimetry to study the geometry and behavior of X-ray sources emitted from supermassive black holes, pulsars, magnetars and supernovae.

The two Missions of Opportunity proposals selected are:

Gal/Xgal U/LDB Spectroscopic/Stratospheric THz Observatory (GUSTO)

GUSTO is an observatory held aloft by a balloon designed to detect high-frequency radio emission from sources in our Milky Way and the Large Magellanic Cloud in order to study the life cycle of interstellar material.

Christopher Walker of the University of Arizona in Tucson is the main scientists on this mission.

LiteBIRD Cosmic Microwave Background Polarization Survey

LiteBIRD is a Japanese space mission with US contributions designed to map polarized fluctuations in the Cosmic Microwave Background in order to search for signs of gravitation waves created during inflation in an effort to better understand the events that occurred during the first moments of the cosmos. 

Adrian Lee of the University of California at Berkeley is a main scientist on this mission.

For more information on NASA’s Explorers Program, go here.

To learn more about NASA’s mandate to travel to the stars and beyond visit here.

Learn more about the Goddard Space Flight Center here.

Discover and explore the Marshall Space Flight Center here

Learn more about the supermassive black hole astronomers believe resides at the center of the Milky Way – the Monster of the Milky Way.

NASA’s New Horizons spacecraft recently arrived at Pluto and its moons. Learn more about what they found?

Read about and learn the things astronomers have discovered during their search for the missing link in black hole evolution.