Concepts for Future High-Energy Astrophysics Missions
This page lists high energy astrophysics (HEA) mission concepts that are
(or were at one time) candidates to be flight programs of US, other national or
international space agencies.
More information on mission studies under NASA's Physics of the Cosmos (PCos)
program office is available at the Physics of the Cosmos web site. In 2011 NASA HQ initiated an X-ray
mission concepts study through the NASA Physics of the Cosmos Program.
The final report of this study listed a number of notional missions,
including a notional calorimeter mission (N-CAL), a notional X-ray grating
spectrometer, AXSIO (see below), a notional wide-field imager (N-WFI), and
various combinations of these capabilities on a single platform.
In July 2015, the High-Energy Large- and
Medium-Class Space Missions in the 2020s Workshop was held in Chicago
to provide input to NASA via its Program
Assessment Groups (PAGs) regarding high-energy large mission concepts and probe
class missions. The meeting included invited talks covering HEA-related large
and medium-class mission concepts along with overviews of HEA science goals
for the 2020s. The presentations at this workshop are available here, and included a number of these mission concepts (the notation
'2015ChiWS' in the list below links to the pdf or ppt version of the
presentation given at the workshop).
US-led (often with international partners)
Advanced Energetic Pair Telescope, a concept for a pair production
telescope for medium-energy gamma-ray polarimetry designed to
achieve angular resolution within a factor of two of the pair production
kinematics limit (~0.6 degrees at 70 MeV), continuum sensitivity comparable
with the Fermi-LAT front detector, and minimum detectable polarization
less than 10% for a 10 mCrab source in 1 Ms.
APT: Advanced Pair Telescope [2015ChiWS]: a mission concept
having 10 times the Fermi LAT geometry factor, with the primary
science being to characterize dark matter by providing measurements
of annihilation spectra and angular distributions of gamma-ray
emission in the 3 - 500 GeV band.
Arcus, a concept for an X-ray grating spectrometer mission to
be placed into a high earth orbit, with a spectral resolution of
> 2500 and an effective area of ~ 550 sq. cm at the critical O VII wavelength
near 21 A, with an overall bandpass from 12 - 50 A (0.25 - 1.0 keV),
enabling a wide range of science objectives, including determining the
composition of minute interstellar dust grains, studying feedback from
supermassive black holes, and exploring structure formation in galaxy clusters.
This mission was selected for a MidEx Phase A concept study in August
AXIS: Advanced X-ray Imaging Satellite,
a NASA Probe Mission Concept to be the premier high (less than 0.3 arcseconds) angular
resolution X-ray mission of the mid-2020s, with a large effective area (4,000 sq cm at
1 keV and 1,000 sq cm at 6 keV) and CCD spectral resolution (150 eV at 6 keV).
EPE: Extreme Physics Explorer: a concept for a
timing/spectroscopy mission that would use micro-channel plate optics
(MCPO) to provide 4 m2 effective area focused to ~1
arc-min onto an X-ray calorimeter.
Energetic X-ray Imaging Survey Telescope, a hard X-ray (5-600 keV)
imaging all-sky deep survey mission that will use a coded-mask
high-energy telescope (HET) with imaging CZT detectors to image
sources such as AGN, black hole transients, etc., in a 70 by 90
degree field of view with 2 arcminute resolution; an accompanying
optical/IR telescope (OIT) will enable multiwavelength studies and
prompt follow-up of gamma-ray bursts.
The Generation X-Ray Mission, a large effective area (50 square
meters at 1 keV,
or 500 x Chandra) X-ray telescope to study the new frontier of
astrophysics: the birth and evolution of the first stars, galaxies,
and black holes in the early Universe.
HEX-P: High-Energy X-ray Probe, a concept for a probe-class
next-generation high-energy X-ray mission with broadband (0.1-200
keV) response and ~40 times the sensitivity of previous missions
above 10 keV.
a concept for a low-cost, wide-field X-ray transient mission on the
International Space Station, with 30 x higher sensitivity compared to
BAT, ASM, MAXI, and designed for transient study of black holes,
neutron Stars, GRBs, etc.
ISS-TAO, the Transient Astrophysics Observer on the ISS,
a proposed Explorer Mission of Opportunity (MoO) for a wide-field
transient detector that would observe numerous transient events every
year due to compact objects, e.g., gravitational wave counterparts,
X-ray bursts, gamma-ray bursts, etc., that was approved by NASA in
August 2017 for a concept study.
The Lynx Space Telescope: a mission concept with a large
gain in collecting area over Chandra and XMM-Newton, an angular
resolution of half an arcsecond, and high-throughput spectroscopy over
a large field of view (FOV). The Lynx mission concept study is being
performed under the leadership of a community-selected Science and
Technology Definition Team (STDT). It is anticipated that the 2020
Astrophysics Decadal Survey Committee will use this and other studies
in formulating their recommendation for the priorities for large
strategic missions of the future.
a concept for a rapid response mission to study the warm-hot
intergalactic medium using
GRBs as its probes, as well as to study the host galaxies of GRBs
and the phyics of GRBs.
TAP: Transient Astrophysics Probe, selected by NASA for an
Astrophysics Probe Mission Concept Study in 2017, is a
multi-instrument (wide-field X-ray and gamma-ray monitors,
high-resolution sensitive X-ray telescope and a wide-field infrared
telescope) platform sensitive to a broad variety of
astrophysical phenomena across the entire sky, with rapid transient
follow up with high sensitivity over a broad energy range.
Xenia: a Probe of Cosmic Chemical Evolution, a concept
for a medium-size cosmology mission (with international collaborators)
which will use gamma-ray
bursts to probe the cosmic 'web', dark energy, dark matter, and
clusters of galaxies.
X-Ray Surveyor [2015ChiWS]: a mission concept with
a large effective area and high angular resolution: i.e., compared to
Chandra, 1-2 orders of magnitude gain in sensitivity and field of view
(with sub-arcsecond imaging), and high-resolution spectroscopy for
both point-like and extended sources, in the 0.2-10 keV band.
Multinational and International (often with US partners)
Transient Astrophysics Explorer, a
mission concept to detect and locate X-ray transients (XRT's), likely
including gravitational wave sources, TDE's, gamma-ray bursts, etc.,
using a wide-FOV coded mask instrument (Owl) to detect XRT's and a sensitive
wide-field focussing soft X-ray instrument (Lobster) to obtain arcminute
or better positions [Europe].
Athena, an X-ray observatory proposed as a concept for a
large effective area
mission for the ESA science program, incorporating a single telescope
with a fixed focal length (12 m) and two interchangeable instruments
in the focal plane, a wide-field imager (WFI) and an X-ray integral
field unit (X-IFU), i.e., an X-ray calorimeter. On Nov 28th, 2013, ESA
selected the science theme "The Hot and Energetic Universe" for
its next large satellite mission (L2), and on Jun 27th, 2014, it
selected Athena as the mission for this theme, with a target launch
date of 2028 [ESA with possible NASA participation].
eXTP, the enhanced X-ray Timing and Polarimetry mission,
a science mission designed to study the state of matter under extreme
conditions of density, gravity and magnetism by making simultaneous
spectral-timing-polarimetry studies of cosmic sources in the energy
range from 0.5-30 keV (and beyond) with a suite of instruments
[China, Europe: circa 2025].
Space Antenna gravitational-wave observatory, a trio of satellites
separated by 2.5 million km designed to detect and accurately measure
low-frequency (10-4 - 10-1 Hz) gravitational
waves as are expected to be produced by binary stars within our galaxy,
binary supermassive black holes (SMBHs) in other galaxies, and
extreme-mass-ratio inspirals and bursts produced by a stellar-mass
compact object orbiting a SMBH. [ESA with possible NASA participation
with a target launch date of 2034]
LOFT: Large Observatory For X-ray Timing ([2015ChiWS]), a mission intended to answer fundamental
questions about the motion of matter orbiting close to the event
horizon of a black hole, and the state of matter in neutron stars,
using a highly capable 10 sq. meter broad-band (1 - 80 keV) X-ray
telescope with 10 μs timing resolution [Europe].
PheniX, a very-broad-band (1-200 keV) high
(<~ 0.5 keV) focussing X-ray telescope able to do Compton polarimetry
for E > 50 keV, and a coded-mask all-sky monitor [Multi-national].
THESEUS: the Transient High Energy Sources and Early
Universe Surveyor, a mission concept proposed in response to the ESA
call for medium-size mission (M5) within the Cosmic Vision Programme,
will have 1) wide and deep sky monitoring in a broad energy band
(0.3 keV - 20 MeV); 2) focusing capabilities in the soft X-ray band
providing large grasp and high angular resolution; and 3) on board
near-IR capabilities for immediate transient identification and
redshift determination. [ESA].
Tsubame, a micro-satellite designed to perform X-ray
polarimetry on gamma-ray bursts [Japan].
XARM, the X-ray Astronomy Recovery Mission, an
approved mission with a target launch date in 2021 that will
"recover" the science that was mostly not possible due to the early
demise of Hitomi (Astro-H), and that will have a moderate-resolution
large-FOV soft X-ray imager (SXT-I) and a high-resolution small-FOV
microcalorimeter array (SXT-S) [JAXA, NASA. ESA].
XIPE: the X-ray Imaging Polarimetry Explorer, a mission
to do cosmic polarimetry in the 2-10 keV band, as well as solar
flare polarimetry in the 15-35 keV band and solar coronal spectroscopy
in the 1.2-15 keV band. XIPE was selected by ESA in June 2015 to
undergo a 2 years-long assessment phase in the context of the Cosmic
Vision M4 competition [ESA].