The James Webb Space Telescope captured its first images and spectra of Mars on September 5, 2022. The telescope, an international collaboration between NASA, the European Space Agency and the Canadian Space Agency, provides a unique infrared sensitivity perspective on our neighboring planet, and complements the data it conducts collected by orbiters and rovers. and other telescopes.
Webb’s unique vantage point approximately 1.5 million kilometers away at Sun-Earth Lagrange point 2 (L2) provides a view of Mars’ visible disk (the part of the sunlit side facing the telescope). As a result, Webb can capture images and spectra with the spectral resolution needed to study short-term phenomena such as dust storms, weather patterns, seasonal variations, and, on a single note, processes that occur at different times (day, sunset, and nighttime) for a Martian day.
Due to its close proximity to the Red Planet, the Red Planet is one of the brightest objects in the night sky in terms of visible light (which the human eye can see) and infrared light that Webb designed to detect. This poses special challenges for the observatory, which is built to detect the very faint light of the most distant galaxies in the universe. Webb’s instruments are so sensitive that without special observing techniques, the bright infrared light coming from Mars would lead to blindness, causing a phenomenon known as “detector saturation.” Astronomers have modified Mars’ extreme brightness using very short exposures, measuring only some of the light hitting detectors, and applying special techniques to analyze the data.
Webb’s first images of Mars, taken by the Near Infrared Camera (NIRCam), show a region of the planet’s eastern hemisphere at two different wavelengths, or colors of infrared light. This image shows a surface reference map from NASA and the Mars Orbiter Laser Altimeter (MOLA) on the left, with the Webb NIRCam instrument’s field of view overlayed. Webb’s near-infrared images are shown on the right.
Webb’s first near-infrared spectrum of Mars, captured by NIRSpec, shows Webb’s ability to study the Red Planet using spectroscopy.
While images of Mars show differences in brightness combined over a large number of wavelengths from one place to another across the planet on a given day and time, the spectrum shows subtle differences in brightness between hundreds of different wavelengths that represent the planet as a whole. Astronomers will analyze features of the spectrum to gather additional information about the planet’s surface and atmosphere.
In the future, Webb will use this imaging and spectroscopic data to explore regional differences across the planet, searching for trace species in the atmosphere, including methane and hydrogen chloride.
These observations of Mars were made as part of Webb’s Guaranteed Time Observation System (GTO) 1st cycle solar system program led by Heidi Hamill of the University Consortium for Research in Astronomy (AURA).
The European Space Agency (ESA) operates two Mars orbiters, the Mars Express and the ExoMars Trace Gas Orbiter, which have brought a treasure trove of insight into the red planet’s atmosphere and surface. Furthermore, the European Space Agency is collaborating with the Japan Aerospace Exploration Agency (JAXA) on the Mars Moon Exploration (MMX) mission, which will soon be launched from Mars moon Phobos.
NIRSpec is built for the European Space Agency (ESA) by a consortium of European companies led by Airbus Defense and Space (ADS) with NASA’s Goddard Space Flight Center providing its detector and miniature subsystems.
Note: This post highlights images from Webb’s flag in progress, which have not yet undergone the peer-review process.