A Comprehensive Overview
Introduction: Cosmological missions refer to scientific endeavors aimed at exploring the universe, studying its origins, structure, and evolution, as well as investigating the fundamental physical laws that govern it. These missions typically involve space telescopes, satellites, and other instruments designed to observe distant celestial objects such as galaxies, black holes, stars, and cosmic microwave background radiation. The goal is to address fundamental questions about the universe, such as its birth, expansion, and ultimate fate.
Instruments used in cosmological missions play an essential role in gathering data, conducting observations, and testing theoretical models of cosmology. These instruments are designed to detect a wide range of electromagnetic radiation (such as visible light, infrared, ultraviolet, and radio waves) and other cosmic phenomena like gravitational waves and cosmic neutrinos, which provide insights into the underlying physics of the universe.
Key Cosmological Missions
- Hubble Space Telescope (HST)
- Launch Year: 1990
- Mission Objective: The Hubble Space Telescope revolutionized our understanding of the universe by providing high-resolution images of distant galaxies, nebulae, and stars. Its observations have contributed to precise measurements of the age of the universe, the identification of exoplanets, and the discovery of distant galaxies.
- Instruments: The HST carries a variety of instruments such as the Wide Field Camera 3 (WFC3), Advanced Camera for Surveys (ACS), and the Space Telescope Imaging Spectrograph (STIS), which allow it to capture images across different wavelengths, from ultraviolet to near-infrared.
- Planck Space Telescope
- Launch Year: 2009
- Mission Objective: The Planck mission was designed to study the Cosmic Microwave Background (CMB) radiation, the faint afterglow of the Big Bang. Planck’s observations helped refine our understanding of the universe’s age, its rate of expansion, and the composition of its large-scale structure.
- Instruments: The Planck satellite was equipped with the Low Frequency Instrument (LFI) and High Frequency Instrument (HFI), which were sensitive to different frequencies of microwave radiation, providing precise measurements of the CMB across the entire sky.
- James Webb Space Telescope (JWST)
- Launch Year: 2021
- Mission Objective: The JWST is considered the successor to Hubble and is designed to observe the universe in infrared wavelengths. Its primary goal is to study the formation of the first galaxies, stars, and planetary systems after the Big Bang, as well as to examine the atmospheres of exoplanets and search for signs of life.
- Instruments: The JWST carries four key instruments: the Near Infrared Camera (NIRCam), the Mid-Infrared Instrument (MIRI), the Near Infrared Spectrograph (NIRSpec), and the Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS). These instruments enable high-resolution imaging and spectroscopy in the infrared spectrum.
- Euclid Mission
- Launch Year: 2023
- Mission Objective: The Euclid mission is focused on studying the nature of dark energy and dark matter. By mapping the geometry of the universe and measuring the expansion rate, Euclid aims to provide critical insights into the accelerating expansion of the cosmos and the role of dark matter.
- Instruments: Euclid carries the Visible Imaging Channel (VIS) and the Near Infrared Imaging Spectrometer (NISP). These instruments are used for deep surveys of galaxies and their distribution, allowing scientists to probe the large-scale structure of the universe.
- Chandra X-ray Observatory
- Launch Year: 1999
- Mission Objective: Chandra is an X-ray telescope designed to observe high-energy phenomena such as black holes, supernovae, and galaxy clusters. Its observations provide critical information about the hot, energetic processes occurring in the universe.
- Instruments: Chandra carries four scientific instruments: the High-Resolution Camera (HRC), Advanced CCD Imaging Spectrometer (ACIS), the High-Energy Transmission Grating (HETG), and the Low-Energy Transmission Grating (LETG), which allow it to study X-rays and map the hottest regions of space.
- SPHEREx Mission
- Launch Year: Planned for 2024
- Mission Objective: SPHEREx (Spatially Resolved Infrared Extragalactic Survey) is designed to map the entire sky in the near-infrared wavelength range. Its primary aim is to study the origins and evolution of galaxies, stars, and planetary systems, and to observe the interactions between galaxies over cosmic time.
- Instruments: SPHEREx will have a single instrument, an infrared spectrometer capable of performing large-scale surveys across a wide range of wavelengths.
- LISA (Laser Interferometer Space Antenna)
- Launch Year: Expected in the early 2030s
- Mission Objective: LISA is a space-based mission that aims to detect and study gravitational waves, ripples in spacetime caused by massive objects such as merging black holes. Gravitational wave astronomy promises to reveal new insights into the dynamics of the most extreme events in the universe.
- Instruments: LISA will consist of three spacecraft arranged in an equilateral triangle, with lasers used to measure tiny changes in the distance between them caused by passing gravitational waves.

Key Instruments in Cosmology
- Radio Telescopes
- Radio telescopes are essential tools in cosmology for observing cosmic phenomena such as pulsars, supernovae remnants, and the distribution of hydrogen gas in the universe. Some notable examples include the Arecibo Observatory (which was decommissioned in 2020), the Very Large Array (VLA), and the Square Kilometre Array (SKA), which will be the largest and most sensitive radio telescope when completed.
- Spectrometers
- Spectrometers are used to analyze the light emitted or absorbed by celestial objects. They allow scientists to measure the chemical composition, temperature, and motion of objects, and are essential tools for understanding the properties of galaxies, stars, and exoplanets. Examples include the spectrometers aboard the JWST and Hubble.
- Interferometers
- Interferometers are devices that combine signals from multiple telescopes to achieve greater resolution than a single telescope could provide. The Event Horizon Telescope (EHT) is an example of an interferometer used to capture the first-ever image of a black hole’s event horizon, specifically the supermassive black hole at the center of the galaxy M87.
- Gravitational Wave Detectors
- Ground-based detectors like LIGO (Laser Interferometer Gravitational-Wave Observatory) and Virgo are critical for detecting gravitational waves. These instruments measure tiny distortions in spacetime caused by cosmic events such as black hole mergers and neutron star collisions. LISA, mentioned earlier, will take these observations to the next level with a space-based platform.
Future Directions in Cosmological Missions
The future of cosmological missions is bright, with upcoming missions and instruments poised to deepen our understanding of the universe. These include next-generation space telescopes like Nancy Grace Roman Space Telescope, which will study dark energy and exoplanets, and Cherenkov Telescope Array (CTA) which will detect high-energy gamma rays from cosmic sources.
With advancements in technology, future cosmological missions are expected to unravel the mysteries of dark matter, dark energy, and the fundamental nature of the universe, potentially answering questions that have remained elusive for centuries.

Conclusion
Cosmological missions and instruments play an indispensable role in expanding humanity’s understanding of the universe. These missions allow scientists to observe the cosmos at unprecedented levels of detail and across a wide range of wavelengths, providing valuable data that shapes our understanding of the universe’s origins, evolution, and underlying physical laws. As technology continues to evolve, cosmological missions will push the boundaries of our knowledge and continue to address some of the most profound questions in science.