The Transient High Energy Sky and Early Universe Surveyor - XGIS I-DHU HW/SW development

Project Details


THESEUS is a space mission concept proposed for ESA M7 science program, aimed at exploiting Gamma-Ray Bursts for investigating the early Universe
and at providing a substantial advancement of multimessenger
and time-domain astrophysics. These goals will
be achieved through a unique combination of instruments
allowing GRBs and X-ray transients detection over a broad
FOV (more than 1sr) with 0.5-1 arcmin localization, an energy
band extending from several MeVs down to 0.3 keV
and high sensitivity to transient sources in the soft X-ray domain,
as well as on-board prompt (few minutes) follow-up
with a 0.7 m class IR telescope with both imaging and spectroscopic

Key findings

Key Findings of the THESEUS Space Mission Concept:

Probing the Early Universe: THESEUS would provide insights into the early Universe by studying Gamma-Ray Bursts (GRBs) and their afterglows.
Advancements in Multimessenger Astronomy: THESEUS aims to combine different types of observations to gain a comprehensive understanding of GRBs and their associated phenomena.
Time-Domain Astrophysics: The mission would study rapidly changing celestial events, such as GRBs, to uncover their behavior and evolution.
Wide Field of View Detection: THESEUS would detect a large number of GRBs and X-ray transients due to its wide field of view, increasing the chances of discovering rare events.
Precise Localization: The mission would accurately determine the location of GRBs, enabling detailed follow-up observations by other telescopes.
Broad Energy Range Detection: THESEUS would study GRBs across a wide energy range, providing insights into different aspects of these cosmic explosions.
Infrared Observations: THESEUS would capture infrared data of GRB afterglows, revealing information about their composition, temperature, and dynamics.
These findings demonstrate the potential of THESEUS to enhance our knowledge of the early Universe, multimessenger astrophysics, time-domain events, and the complexities of GRBs.

Layman's description

THESEUS is a space mission idea that has been proposed to the European Space Agency (ESA). Its main purpose is to study Gamma-Ray Bursts (GRBs) in order to learn more about the early Universe. Additionally, it aims to make significant advancements in the fields of multimessenger and time-domain astrophysics.

To achieve these goals, THESEUS would carry a unique set of instruments. These instruments would allow it to detect GRBs and X-ray transients (sudden changes in X-ray emission) over a wide area of the sky, more than one square degree. It would also be able to precisely determine the location of these events, with an accuracy of 0.5 to 1 arcminute.

THESEUS would be able to detect gamma rays with energies ranging from several million electron volts (MeVs) down to very low X-ray energies of 0.3 kiloelectron volts (keV). This wide energy range is important because it allows scientists to study different aspects of these cosmic explosions.

The mission would also have a high sensitivity to transient sources in the soft X-ray range, which means it would be able to detect and study short-lived and rapidly changing X-ray sources. In addition, THESEUS would have an infrared (IR) telescope with a mirror size of around 0.7 meters. This telescope would be capable of capturing both images and spectra of infrared light. With this instrument, THESEUS could quickly observe and analyze the GRB aftermath in the infrared part of the electromagnetic spectrum, just a few minutes after the initial burst.

Overall, THESEUS aims to provide a comprehensive understanding of GRBs, their origins, and their impact on the early Universe. By combining different types of observations and utilizing advanced instruments, the mission would significantly contribute to our knowledge of astrophysics, particularly in the areas of gamma-ray and X-ray astronomy.
Short title THESEUS
Effective start/end date01/09/201931/08/2023

Collaborative partners

  • Technical University of Denmark
  • INAF - Osservatorio Astonomico di Arcetri (lead)
  • University of Leicester (Project partner)
  • Institut de recherche sur les lois fondamentales de l'Univers (Project partner)
  • University of Geneva (Project partner)
  • University of Tübingen (Project partner)

UN Sustainable Development Goals

In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):

  • SDG 9 - Industry, Innovation, and Infrastructure
  • SDG 17 - Partnerships for the Goals


  • ransient High Energy Sky and Early Universe Surveyor
  • Ancient Gamma-ray Burst


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