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MOSSAIC: Multi-messenger Operational Science Support & Astrophysical Information Collaboration

Communication, Coordination, and Collaboration in Multimessenger Astrophysics


Working with partners.

Multimessenger and Time Domain Astrophysics (MMA/TDA) are, by design, collaborative disciplines. Progress in this field depends on many stakeholders working together efficiently - not only scientists from the astronomy and physics, ground- and space-based communities, but also engineers, software developers, data and communication scientists, and more. The vision at the core of MOSSAIC is the recognition that progress in MMA/TDA science can only be achieved if all stakeholders Communicate (often and regularly), Coordinate (plan and execute together), and Collaborate (share ideas and tools) - the three Cs. The challenges to MMA/TDA of the 21st century, with the improved sensitivities of ground- and space-based facilities, require nothing less.

MOSSAIC is an initiative of two NASA Centers (Goddard and Marshall Space Flight Centers), with a vision to include other stakeholders from Universities, government Labs, non-profits, and industry as active partners. It brings together current research, capabilities, and resources needed to support MMA/TDA scientists around the world. MOSSAIC is primarily intended as a service to the community, to facilitate connections between ground- and space-based observers, theorists, and data scientists from the astronomy and physics fields. It also aims to provide data analysis and interpretation tools, observations planning capabilities, proposal preparation and submission support, mission concept development, and more. Each MOSSAIC partner has equal weight and provides unique contributions, and has pledged to work with the others while maintaining their identity and autonomy.

Current MOSSAIC partners:

We invite you to be part of our community by contacting us at mossaic@bigbang.gsfc.nasa.gov. We look forward to working with you!

Astrophysics has entered a new era. Multi-messenger astrophysics (MMA) has come of age thanks to the detection of gravitational wave (GW) sources from the ground with the LIGO and Virgo observatories, and of an extragalactic neutrino source with the IceCube Neutrino Observatory. Together with the concurrent observations of photons, these discoveries provide new insights into the physics of the Universe. Time Domain Astrophysics (TDA) will soon enjoy a renaissance with the soon operational Vera Rubin Observatory, SKA, ngVLA, Roman Space Observatory, and other wide-field survey instruments. The importance of MMA and TDA has been recognized by the 2020 Astrophysics Decadal report, which highlights their breakthrough potential and the need for adequate capabilities in space and on the ground, as well as the need for supporting infrastructure and coordination.

The advent of the next generation of ground-based gravitational wave and neutrino detectors in a few years, and of LISA in the 2030s, will expand the discovery horizon and multiply the number of sources requiring prompt EM follow-up from the ground and in space. The needs of the MMA community will increase many-fold: primarily the need for coordination, collaboration, and communication (the 3Cs) between the space- and ground-based facilities; the need for adequate infrastructure (data analysis and interpretation tools, efficient alert systems, proposer and observer support, rapid data transmission links, etc.); and the need for common and frequent brainstorming together to anticipate needs and provide solutions. New missions will be designed to meet the increasing science objectives of MMA/TDA.


MOSSAIC unites two NASA Centers, GSFC and MSFC, and various Institutions and Universities in the US, in the common pursuit of enabling and supporting time domain and multi-messenger science. The aim of the Collaboration reflects the nature of the science, which is intrinsically collaborative and inclusive, each piece of the MOSSAIC providing an essential contribution to the whole picture. These are the partners of MOSSAIC:

NASA's Goddard Space Flight Center:
The largest NASA science Center, GSFC hosts a range of MMA/TDA capabilities, expertise, and services, including: mission concept development in all lifecycle stages; data analysis, interpretation, and archiving; computing and theory; space communications; Guest Observer Facilities, with proposal planning tools and submission support; and AI/ML capabilities of interest to MMA/TDA operations. Community development and support is a long-standing tradition at GSFC.

NASA's Marshall Space Flight Center:
MSFC participation in MOSSAIC brings comprehensive expertise in X-ray, gamma-ray, and gravitational wave astrophysics, with involvement in missions ranging from the CGRO BATSE, Fermi GBM, IXPE, and StarBurst. MSFC manages the Fermi GBM experiment and center scientists provide NASA leadership to the long-standing GW-GRB working group that helped coordinate the GW/GRB 170817 discovery, are leading the effort to modernize the interplanetary network, and are developing standard toolkits for future MMA/TDA missions based on the software developed for Fermi GBM. MSFC also brings mission concept development and AI/ML capabilities, as well as world class test facilities.

Our University partners have a central role for STEM education and community development. They provide nexi for connecting observers, theorists, computing and data scientists who work with the Centers in all MOSSAIC activities, providing cauldrons of innovation. They lead activities not possible at the Centers because of restrictions and regulations, and as such, play a vital role in MOSSAIC.

What we do


MOSSAIC partners have a long tradition of designing, developing, building, and managing small and medium-size missions which are crucial to MMA and TDA. In the following we focus on the NASA Centers, where many of the current and future MMA/TDA missions are operated, while acknowledging that Universities and other Institutions are also leaders in the field and are contributing to the MMA/TDA mission portfolio in a significant way: they provide subject matter experts, connection to the community, and lead STEM initiatives.

Explorer-size missions currently developed and/or managed by GSFC and MSFC include the Neil Gehrels Swift Observatory, the Fermi Gamma-ray Observatory, NICER, and IXPE. In addition, with its field of view 200 times larger than Hubble and near infrared sensitivity, the Roman Space Telescope, NASA's next flagship for launch no later than 2027, is particularly suited for time domain studies. Two of Roman's Core Community Surveys focus on the Time Domain: a time domain survey of the galactic bulge at 15 min cadence, and a high latitude survey at 5 day observing cadence. These will open new discovery space for galactic and extragalactic time domain and transient science.

There are other upcoming, smaller missions that will add to this landscape of GRB detectors including BurstCube (CubeSAT led by GSFC), Glowbug (ISS payload led by NRL) and StarBurst (Pioneer led by MSFC). The GRB nanosats group is an international effort to share information and build collaboration amongst GRB-detecting instruments. This included a workshop in 2018, and regular virtual meetings. A future workshop is being planned for 2022/2023.

Fermi/Ligo GW Plots

GSFC is also a partner in COSI, a soft gamma-ray survey telescope (0.2-5 MeV) designed to probe the origins of Galactic positrons, uncover the sites of nucleosynthesis in the Galaxy, perform pioneering studies of gamma-ray polarization, and find counterparts to multi-messenger sources. COSI is led by a Team at University of Berkeley, while GSFC is contributing ...

Services provided at the two Centers to the community for mission development feature the expertise and experience of our scientists, engineers, and program managers, as well as mission and instrument concept design labs, where architectures are fleshed out in detail and costed. Our technologists are available for advice on technology maturation, and assistance with technology roadmap. GSFC and MSFC work with external PIs to realize missions addressing MMA/TDA science; including the development of Science Traceability Matrices, detailed sensitivity simulations (see Computing and Theory below), detection rate analysis, grass-root and independent costing, and risk assessment.

Alert Notices

A central activity of MOSSAIC is the GCN/TAN (Gamma-ray Coordinates Network/Transient Astronomy Network), which has provided automated rapid notification of high-energy and multimessenger transients since the early 1990's, and was integrated permanently into the HEASARC in October 2016. As a result, the GCN hardware was upgraded in 2017, and many new notice types have recently been added. MOSSAIC members already collaborate closely with the gravitational wave network (LIGO/Virgo/KAGRA collaboration), and the neutrino network (AMON; Astrophysical Multi-messenger Observatory Network), to disseminate multimessenger alerts for gravitational wave events, and high energy neutrino detections.

The Figures below illustrate the distribution of worldwide users who subscribe to the GCN services, both for GCN Notices(left) and GCN circulars (right). Caveats: These are constructed from assumptions based upon email addresses, GCN does not collect location information, and data below country level are not accurate. Some users also receive alerts via external email exploders, and that is not captured in these maps.

Circulars [Open in a new window]

Community Services
(GOFs, HEASARC, tools for proposers and observers)

Historically, GSFC and MSFC developed and hosted many services to support space-based observers. GSFC currently provides a data archive for high-energy missions. The High Energy Astrophysics Science Archive Research Center (HEASARC) is NASA's archive for high-energy astrophysics and cosmic microwave background data, and leads the General Observer/General Investigator programs for many of NASA's Explorers class missions (read more below). MSFC scientists have likewise developed gamma-ray data portals that currently serve as resources for the time-domain and multi-messenger communities.

MMA/TDA General Observer Facility (GOF):
Building on our history of serving the General Observer community, MOSSAIC will feature a GOF for MMA/TDA proposers of ground and space-based missions, operated virtually by various MOSSAIC partners. We aim at providing tools that allow observers to plan and execute observations for multi-wavelength campaigns and EM follow-up of multi-messenger sources (see for example the M4OPT tool), and support for preparing and submitting proposals.

Tools for gamma-ray astrophysics:
MOSSAIC scientists have also harnessed their unique knowledge and experience in gamma-ray astrophysics to develop publicly accessible software tools to further enable future MMA/TDA missions. These tools include standardized gamma-ray mission toolkits, many of which build upon software written for Fermi GBM and include on-board and ground-based event detection, localization, and classification algorithms, as well as the development of detector responses and atmospheric scattering models, and comprehensive light curve and spectral analysis tools. These toolkits are intended to serve as a resource to the MMA/TDA communities, allowing scientists to more easily combine and analyze data from multiple gamma-ray satellites and develop and implement MMA/TDA missions in the future.

Using these tools, MOSSAIC scientists are also developing software to enable a coherent multi-mission event detection algorithm that would combine the sensitivities of all gamma-ray detectors that simultaneously observe the time and location of a transient event. This software lays the supporting framework for a coherent search from data collected by a future network of gamma-ray capable smallSats.

IPN modernization:
MOSSAIC scientists are taking the lead on modernizing the software underpinning the InterPlanetary Network (IPN), which has long been used to provide precise localizations of high-energy transients. In the era of multi-messenger and time domain astronomy, the importance of the IPN cannot be understated. The precise, in some cases arcminute, localizations provided by the IPN can be crucial to associating high-energy transients to multimessenger detections and further enable follow-up at other wavelengths and messengers by vastly reducing the search area on the sky. The tools being developed by MOSSAIC scientists will allow future MMA/TDA missions to more easily participate in the network and provide modern tools for the community to utilize the results provided by the IPN.

Community Portal:
Based on the 3Cs core values, MOSSAIC features a portal for the community to post messages in real time, allowing observers to coordinate their observations on the ground and in space, and avoiding duplication of efforts. This portal will be hosted by one or more of our University partners.

High Energy Data Archive:
Over the past 30 years, the HEASARC has transformed the way NASA astrophysics data are accessed and analyzed. The HEASARC's innovative archive interfaces and multi-mission software allow scientists to identify, download, display, correlate, and analyze scientific data from dozens of missions. The data and software standards developed by the HEASARC provide the underlying infrastructure for the analysis of NASA (and ESA and JAXA) high energy astrophysics data. The HEASARC serves as the active archive for a number of currently operating missions (Chandra, Fermi, INTEGRAL, MAXI, NICER, NuSTAR, Swift, and XMM-Newton) and is preparing to support upcoming high-energy astrophysics missions (IXPE, BurstCube, Starburst, and XRISM) along with various suborbital experiments, other CubeSats, and SmallSats.

Theory and Simulations

MOSSAIC aims to connect computation, theory, and data scientists to observers in order to facilitate the development of science cases for missions, concepts, proposals, and more. MOSSAIC scientists contribute expertise to the external community by informing the planning of MMA/TDA mission concepts through a variety of services: (1) determining the science reach of a proposed mission design; (2) providing the physical context for observations from operating missions; (3) establishing connections between different types of data taken simultaneously or at different times; and (4) developing a roadmap for future missions.

Development and maintenance of software and computational modeling tools for use in the wider MMA and TDA community is in the purview of MOSSAIC.

MOSSAIC scientists have been at the forefront of MMA/TDA theory for decades, with research in a variety of topics:

  • GW (vacuum) simulations of binary black holes
  • Radiation transport around black holes and binary black holes
  • General Relativity Magneto Hydro Dynamic (GRMHD) simulations of accretion flows around binary black holes (e.g., Figure below)
  • Gamma rays, cosmic rays, and neutrinos:
      - Cosmic ray acceleration, propagation, and interactions
      - Gamma-ray and neutrino emission from starburst galaxies, AGNs, GRBs, etc.
  • Pulsar magnetospheres and gamma-ray light curves, which are probes of extreme physics and essential constituents of pulsar timing arrays
  • Simulations of neutron star mergers and their post-merger phase of evolution to the kilonova stage
  • ... And more

In some cases, certain data interpretation and mission planning activities are appreciably widespread within the larger MMA community to motivate the development of sufficiently generic and user-friendly software or computational tools for public use. The MOSSAIC scientists work together in efforts to develop publicly distributed software, particularly in the areas of GW data analysis, GRMHD, radiative transfer, and high-energy particle propagation.

Developing software and computational modeling tools for use in the wider MMA and TDA community is in the purview of MOSSAIC scientists. In some cases, certain data interpretation and mission planning activities are appreciably widespread within the larger MMA community to motivate the development of sufficiently generic and user-friendly software or computational tools for public use. The MOSSAIC scientists will work together in efforts to develop publicly distributed software, particularly in the areas of GW data analysis, GRMHD, radiative transfer, and high-energy particle propagation.

A binary black hole system viewed nearly edge-on, with both black holes hosting their own mini-accretion disk.
A binary black hole system viewed nearly edge-on, with both black holes hosting their own mini-accretion disk. Extreme gravitational lensing produces multiple images of the blue accretion disk in the background, lensed by the foreground black hole with the red accretion disk.
X-ray emission from a pair of supermassive black holes close to merger accreting hot magnetized gas viewed at an angle of 72 degrees off the orbital plane of the binary.
X-ray emission from a pair of supermassive black holes close to merger accreting hot magnetized gas viewed at an angle of 72 degrees off the orbital plane of the binary. The image is made using decoupled radiative transfer (BOTHROS; Noble et al. 2007, Classical and Quantum Gravity, 24, S259) and 3D GRMHD (HARM3d; Noble et al. 2012, ApJ, 755, 51) codes. Higher fidelity models of the time-varying emission that can be compared with observations require fully coupled radiation and 3D GRMHD simulations.
The distribution of plasma density (color scale at right) near two supermassive black holes orbiting each other with magnetic field lines (white lines) emanating from the inner accretion region.
The distribution of plasma density (color scale at right) near two supermassive black holes orbiting each other with magnetic field lines (white lines) emanating from the inner accretion region. The dataset is from a 3D GRMHD supercomputer simulation using the HARM3d code.

Space Communications and Navigation Network Services

Networked communications enable individual MMA/TDA observatories to operate as a cohesive observation system. Space-based MMA/TDA observatories use network services to maintain precise orbit and timing state knowledge, perform flight control responses to transient events and exchange time-sensitive data for distributed science operations. Goddard's Exploration and Space Communications (ESC) Division (https://esc.gsfc.nasa.gov) brings together diverse space communications, internetworking and flight navigation expertise from across the Agency to advise the MOSSAIC community and facilitate implementation of network solutions for MMA/TDA missions and multi-mission observation concepts.

The NSN serves as the single point of contact for network service planning and operations for NASA missions.

The NSN serves as the single point of contact for network service planning and operations for NASA missions venturing up to two million kilometers from Earth. NSN integrates an evolving set of commercial, international and U.S. government network service providers into a cohesive, reliable, and secure network infrastructure. A snapshot of NSN network assets in 2022 is illustrated above.

MOSSAIC community needs are driving concepts and technologies that allow automated internetworking between terrestrial and space network infrastructure. For example, a recent collaboration between Swift and ESC resulted in new methods for MMA/TDA missions to rapidly send follow-up commands to their observatories in response to alerts from the GCN (https://arc.aiaa.org/doi/pdf/10.2514/1.I010897). Swift's autonomous follow-up capability is expected to provide an increase in the rate of detections of electromagnetic counterparts to gravitational wave events like GW170817 by greater than 400% (https://doi.org/10.3847/1538-4357/aba94f). Additionally, ESC is engaged in spectrum policy negotiations and space-qualified wireless terminal technology transfer activities to allow commercial personal satellite communications networks, broadband satellite internet constellations, and 5G mobile wireless networks to be leveraged by space-based users.

The MOSSAIC community will benefit from the emergence of a diverse commercial direct-to-Earth and space relay network service provider ecosystem. The Near Space Network (NSN) serves as a single point of contact for network service planning and operations. The NSN matches mission needs with the capabilities offered by the commercial market and maintains purchasing agreements with a diverse set of interoperable network service providers. For unique mission requirements unable to be fulfilled by the commercial market, NSN facilitates mission integration with government-owned infrastructure such as the Tracking and Data Relay Satellite (TDRS) constellation. A current map of the NSN commercial and government infrastructure is provided in the figure below. More information about NASA's commercial services strategy can be found here (https://www.nasa.gov/directorates/heo/scan/services/nasas_commercial_communications_services/FAQ).

Data Mining with AI/ML

The volume of astrophysical data being produced on a daily basis is beyond human ability to manually examine. The advent of Artificial Intelligence and Machine Learning (AI/ML) technology promises to revolutionize how large data volumes are handled and analyzed. MOSSAIC's scientists are engaged widely in AI/ML, and as such, poised to maximize MMA science in the era of big data.

Capabilities include the Discover supercomputer and the ADAPT/Prism GPU cluster at the NASA Center for Climate Simulation (NCCS), recently used to produce more than 100 million TESS light curves (see https://www.nccs.nasa.gov/news-events/nccs-highlights/light-curves). AI/ML has been used to examine these light curves in many ways, to include the identification of ~300,000 previously unknown eclipsing binary systems, expanding the known number of these systems by two orders of magnitude.

Similar novel computing approaches will be critical for MMA/TDA, where large numbers of incoming alerts will require parsing and prioritization and disparate data from different instruments will need to be combined and jointly analyzed to yield new results. In order to truly leverage the power of MMA/TDA, algorithmic methodologies must be employed to properly characterize and analyze the data. These methods can provide value for a simple application such as spatiotemporal correlation, or for a method as complex as multi-dimensional embedding space characterization.

Though MMA/TDA data is diverse, AI/ML analysis can provide new insights and understanding to astrophysical phenomena through an emphasis on this diversity. Historical understanding of sources through the lens of a single type of data has the potential to be revolutionized through combining the disparate MMA data. Outlier or novelty detection can identify sources that demonstrate unique characteristics in different energy bands or in the interrelationship between energy bands. The utility of this approach is the automation of certain functions, for example, searching through the millions of daily transients delivered by Rubin to select targets for follow-ups from space and ground according to pre-established criteria.

Community Support and Development

MOSSAIC is deeply connected to various MMA and TDA communities through research and services, including the scientists worldwide, mission operations staff, and infrastructure developers. Connection is essential because MMA is a global enterprise and cannot flourish without a concerted and coordinated effort of many parties. Facilitating collaboration, innovation, and exchange of ideas is one of the core values of MOSSAIC.

Connection is essential to disseminate findings, ideas, and new technologies, and to form efficient interfaces, among NASA missions and between NASA and ground-based facilities. These functions flow naturally from the existing ties of our scientists to other MMA groups (SCIMMA, AMMON, GROWTH, the GW-BRB working group, etc.), from our experience in operating NASA missions and related GOFs, and from our expertise in the field of MMA and TDA science.

The nature of MMA is naturally conducive to engage diverse groups. Research shows that the solution space increases dramatically with the inclusion of diverse viewpoints and experiences, and MMA is no exception. An inclusive, diverse, and accessible environment is the foundation of all the work we do.

Activities sponsored by MOSSAIC will include: training of students and early career scientists via paid internships and term positions; open workshops and conferences to disseminate the most recent advances in MMA/TDA science, both observation and theory; and training events for the general community to learn how to use new analysis tools and to find expertise in data analysis and interpretation.

We plan on expanding our connections to local and national organizations serving under-represented populations (e.g., the Multimessenger Diversity Network) through a host of events targeted to students and other early career scientists.

MOSSAIC and the Future of MMA/TDA

The future of MMA/TDA is just starting. As the sensitivities of ground-based GW and neutrino Observatories continue to improve, we will witness an explosion of sources (some expected, many unexpected) that will need prompt EM follow-up from the ground and space. With Rubin becoming fully operational in 2023, the number of transients per night will skyrocket, and we will face the dilemma of deciding which ones to follow at other wavelengths, especially at high energies.

Building on our current activities, MOSSAIC will continue to grow and provide necessary services to the community. This will not be done in isolation, as MMA/TDA is intrinsically a collaborative discipline and all stakeholders' input is needed to achieve real science progress. MOSSAIC is conceived as a fulcrum for the community to come together. Just as the different pieces of a mosaic, the MOSSAIC communities come together to paint the whole canvas of MMA/TDA science.


International MMA/TDA Workshop in August 2022

The NASA PCOS/COR Program Office announces an upcoming international workshop on Time Domain Astronomy/Multi-Messenger Astrophysics (TDAMM). Held in the Baltimore/Annapolis area August 22-25, 2022, the workshop will gather the astrophysics community, both ground- and space-based, for identifying the science questions in TDAMM for the next decade. This will allow NASA to move forward with the implementation of the 2020 Decadal Survey for the field. More details about the workshop will be forthcoming.

If interested in receiving TDAMM workshop related communications, send an email to: