Astrophysics Pioneers
The Pioneers Program, started in 2020, is intended to carry out compelling astrophysics science, at a lower cost and using smaller hardware than missions in the Explorers Program. Current Pioneers missions include SmallSats, major balloon payloads, and modest payloads attached to the International Space Station, with a $20M cost cap.
Operating missions:
- Pandora, launched Jan. 11, 2026, is a SmallSat that will study at least 20 stars and their 39 exoplanets in visible and infrared light. It is aimed at disentangling the signals from stars and planetary atmospheres. Understanding how changes in starlight affects measurements of exoplanets is an outstanding problem in the search for habitable planets beyond the solar system. The principal investigator is Elisa Quintana of NASA's Goddard Space Flight Center.
Missions in development:
- Aspera is a SmallSat that will study galaxy evolution. Through observations in ultraviolet light, it will examine hot gas in the space between galaxies, called the intergalactic medium, and the inflow and outflow of gas from galaxies. The intergalactic medium is a major component of the universe but is poorly measured; Aspera would close this gap after it launches in 2027. The principal investigator is Carlos Vargas at the University of Arizona.
- GOSoX (Globe Orbiting Soft X-ray) is a small satellite that will observe low-energy X-rays from more than a dozen cosmic objects to study their polarization, or the orientation and level of alignment of the incoming photons of light. When GOSoX launches in 2029, these measurements will offer new insights into the geometry of relativistic jets and complement missions like NASA’s IXPE (Imaging X-ray Polarimetry Explorer) that study higher-energy X-rays. GOSoX technology was previously tested on the REDSoX (Rocket Experiment Demonstration of a Soft X-ray Polarimeter) sounding rocket mission. The principal investigator is Herman Marshall at the Massachusetts Institute of Technology.
- The Landolt mission, named for the late astronomer Arlo Landolt, will put an artificial “star” in orbit around Earth, allowing scientists to calibrate telescopes and more accurately measure the brightness of stars ranging from those nearby to the distant explosions of supernova in far-off galaxies. By establishing absolute flux calibration, the mission will begin to address several open challenges in astrophysics including the speed and acceleration of the universe's expansion. Landolt is slated to launch in 2029, and the principal investigator is Peter Plavchan of George Mason University.
- POEMM (Planetary Origins and Evolution Multispectral Monochromator) is a balloon-borne 1.8-meter telescope, combined with state-of the-art spectrometers and detectors developed by the POEMM team, to study planet formation and evolution with uniquely powerful far-infrared diagnostic tools. The payload is slated to launch on a Super-Pressure Balloon for an ultra-long-duration flight around 2028. The principal investigator is Gordon Stacey at Cornell University.
- PUFFINS (Polarimetry in the Ultraviolet to Find Features in INterStellar dust) is a small satellite designed to study the effect of interstellar dust on ultraviolet light from about 70 distant stars. After its launch in 2029, PUFFINS will observe the polarization this light to reveal properties of the smallest grains of dust in the interstellar medium, improving our understanding of how this dust forms, evolves, and influences star and planet formation. The principal investigator is Ramya Anche at University of Arizona’s Steward Observatory.
- StarBurst is a SmallSat that will detect high-energy gamma rays from events such as the mergers of dense stellar remnants called neutron stars. This will provide valuable insight into such events, which are also detected through gravitational waves by observatories on Earth. These events are where most of the heavy metals in the universe, such as gold and platinum, are formed. To date, only one such event has been observed simultaneously in gravitational waves and gamma rays; StarBurst, with a target launch date of summer 2027 (aligned with LIGO's O5 observing run), aims to find up to 10 every year. The principal investigator is Daniel Kocevski of NASA's Marshall Space Flight Center.
Past missions:
- PUEO (Payload for Ultrahigh Energy Observations) was a balloon mission to detect signals from ultra-high energy neutrinos, particles that contain valuable clues about the highest energy astrophysical processes, including the creation of black holes and neutron star mergers. Neutrinos travel across the universe undisturbed, carrying information about events billions of light years away. PUEO was designed to carry out the most sensitive survey of cosmic ultra-high energy neutrinos ever conducted. PUEO was successfully launched from NASA Long-Duration Balloon camp near McMurdo Station, Antarctica, on Dec. 20, 2025. The payload reached a float altitude of 35 kilometers and circumnavigated the Antarctic continent for 23 days, using the vast ice sheet below as detection volume for impulsive radio signals of neutrino interaction in the thick ice sheet. The payload landed ~300 kilometers from the Scott-Amundson South Pole Station. Payload and data vaults have been recovered by ground traverse. The principal investigator is Abigail Vieregg of the University of Chicago.
