NASA, ESA, And The Use Of Infrared In Space

By John Oncea, Editor

Infrared astronomy revolutionized space exploration, revealing hidden cosmic phenomena. From early discoveries to advanced space telescopes, it enables the study of cool objects, distant galaxies, and exoplanets.

Infrared (IR) – part of the electromagnetic spectrum along with radio waves, UV light, visible light, X-rays, and gamma rays – is a type of electromagnetic radiation that is invisible to the human eye but can be detected as heat. People interact with IR every day, from using a remote control to channel surf, to toasting bread to go with your breakfast.

NASA and the European Space Agency (ESA) use IR, too. For instance, IR can help study weather, climate change, and objects that are difficult to see in visible light. It can help detect objects that are too faint or cool to be seen in visible light, such as planets, nebulae, and cool stars. And IR is used by the James Webb Space Telescope (JWST) to study the earliest stars and galaxies, as well as to see through dust to study star formation.

A Brief History Of The Use Of IR In Space Exploration

In 1800, astronomer William Herschel used a prism to refract light from the sun and detected the infrared, beyond the red part of the spectrum, through an increase in the temperature recorded on a thermometer, writes Oxford Academic. Fifty-six years later Charles Piazzi Smyth conducted the first infrared astronomical observations, detecting IR from the Moon.

The early 1900s witnessed the development of more sensitive IR detectors such as thermopiles which allowed for the initial measurements of stars and planets. Post-WWII, military night vision technology using cooled lead sulfide detectors was adapted for astronomy. In the 1960s, improved detectors are used on aircraft, balloons, and rockets to observe infrared sources in space.

Then, in 1967, the Becklin-Neugebauer object was discovered, demonstrating IR’s ability to reveal hidden celestial objects. Over the next decade, dedicated IR telescopes were established at ground-based observatories.

Starting in the early 1980s, IR was used during space missions, starting with Infrared Astronomical Satellite (IRAS) launches that conducted the first all-sky infrared survey. Other instances of IR use during space missions include:

• 1995: ESA launches Infrared Space Observatory (ISO), greatly improving IRAS capabilities.
• 2003: NASA launches Spitzer Space Telescope, providing advanced IR imaging and spectroscopy.
• 2009: ESA launches Herschel Space Observatory, the largest IR telescope at the time.
• 2021: Launch of James Webb Space Telescope, the most advanced IR observatory to date.

The use of IR by NASA and the ESA has revealed hidden star-forming regions and young stars, detected dust disks around stars indicating planetary systems, studied the chemical composition of interstellar gas and dust, observed distant galaxies and the early universe, and analyzed atmospheres of exoplanets.

The progression shows how IR astronomy evolved from initial discoveries to becoming a crucial tool for exploring the cool and hidden universe, with space-based observatories overcoming atmospheric limitations to provide revolutionary new views of the cosmos.

Why Infrared Is Used In Space

IR astronomy and detection is widely used in space exploration for several reasons, including its ability to penetrate cosmic dust and gas clouds that block visible light. This allows astronomers to observe objects and regions that would otherwise be hidden, like star-forming regions inside nebulae or the centers of galaxies, according to NASA.

It is also helpful in detecting cool/cold objects. Many astronomical objects like planets, asteroids, brown dwarfs, and cool stars emit most of their energy into the IR, and IR telescopes can detect these cooler objects that may be invisible in optical light. Other benefits of using IR in space include:

1. Observing distant/early universe: Light from very distant galaxies is redshifted into IR wavelengths due to the expansion of the universe. According to Sky At Night Magazine, IR observations allow astronomers to study some of the earliest and most distant galaxies.
2. Studying star and planet formation: Newly forming stars and planets are often surrounded by dust that absorbs visible light. IR can penetrate this dust, allowing astronomers to study these young objects.
3. Analyzing chemical compositions: Many molecules and chemical compounds in space have unique spectral signatures in IR light. This allows astronomers to determine the composition of distant objects and atmospheres.
4. Thermal imaging of planets/moons: IR can be used to map temperature differences on the surfaces of planets and moons in our solar system.
5. Tracking asteroids and near-Earth objects: Some asteroids are very dark and hard to see in visible light, but are more easily detectable in IR.
6. Penetrating Earth’s atmosphere: Some IR wavelengths can pass through Earth’s atmosphere more easily than visible light, allowing ground-based IR telescopes to observe from Earth.

These IR-enabled discoveries have greatly expanded our understanding of the universe by revealing previously hidden cosmic phenomena and allowing astronomers to study objects across a wider range of the electromagnetic spectrum.