# Gamma-ray Bursts: 50 Years and Counting!
## 11 Future Prospects
The Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a mission proposal to the European Space Agency for a satellite telescope with the main objective of using GRBs to study the Early Universe and will be invaluable for multi-messenger and time-domain astrophysics in general [220; 221]. To achieve these goals, THESEUS will host three instruments on board whose combination will allow GRB and X-ray transient detection over an extensive field of view with accurate localization (\(\sim\)0.5-1 arcmin) over a wide energy range. These instruments will be a Soft X-ray Imager (SXI) sensitive between 0.3 and 6 keV with a wide FoV (\(\sim\)1 sr) and a great angular resolution (\(\sim\)1-2 arcmin), an InfraRed Telescope (IRT) operating in 0.7-1.8 um with both imaging and (some) spectroscopic capabilities, and an X/Gamma-ray Imaging Spectrometer (XGIS), a set of coded-mask cameras sensitive in an unprecedented 2 keV-20 MeV energy range. With this instrumentation, THESEUS will be perfect for studying the most distant high-redshift GRBs, offering a unique opportunity to delve into pivotal unresolved questions within modern cosmology. These inquiries encompass understanding the population of low-mass and low-luminosity primordial galaxies and exploring the origins and the evolution of cosmic re-ionization, and the results will contribute to our comprehension of the evolution of the Star Formation Rate (SFR) and metallicity up to the \"cosmic dawn\" and through Pop-III stars [222]. Furthermore, THESEUS, by enabling the precise localization, identification, and in-depth study of the electromagnetic counterparts of GW and neutrino sources, will bring fundamental advances in multi-messenger and time-domain astrophysics. We also mention the GAmma-ray burst Localizing Instrument (GALI) proposal [223]. GALI is a new concept for identifying the positions of GRBs by using numerous small scintillators in a 3D array using their mutual shielding. GALI can be thought of as an omnidirectional coded-mask detector, where the mask itself, rather than being applied externally to the detector, is made up of the grid of the sensor elements themselves. Furthermore, the detector (and therefore the mask) does not have a preferred direction and therefore provides coverage of the entire sky, unlike traditional coded-mask instruments. The GALI concept of using mutual masking of modular detector elements can be scaled to any size, thus adapting to a multitude of different missions. In particular, larger versions of the detector, with more elements, in addition to having greater sensitivity, will obtain a great improvement in angular resolution compared to smaller versions. However, simulations show how even a small detector, with a total volume of just \(\sim\)1 L, could identify the direction of a burst down to approximately \(\pm 2\) for a 1 s GRB in the 10 keV-1 MeV range and a flux of \(\sim\)10 ph cm\({}^{-2}\)s\({}^{-1}\). While GALI is capable of functioning as a standalone instrument aboard a single satellite, its versatility extends to its integration within a distributed satellite architecture. This incorporation enhances both the sky coverage and the localization capabilities of the entire satellite constellation. On 9 January 2024, the Einstein Probe (EP), a joint mission of the Chinese Academy of Sciences, the European Space Agency, and the Max Planck Institute for Extraterrestrial Physics [224], was successfully launched. The EP is a space satellite for the observation and monitoring of transient X-ray phenomena, which will exploit the combination of two instruments: a Wide-field X-ray Telescope (WXT) [225], which uses lobster-eye optics to obtain an FoV of approximately 3600 square degrees in the range 0.5 \(\sim\) 4.0 keV, and the Follow-up X-ray Telescope (FXT) [226], a Wolter-I type of X-ray telescope highly sensitive between 0.3 and 10 keV, for observations of transients identified by WXT. Finally, we mention some NASA mission proposals at various stages of development and financing.