NASA SPHEREx Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer Mapping the sky to investigate Cosmic Origins
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NASA National Aeronautics and Space Administration NASA SPHEREx Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer Mapping the sky to investigate Cosmic Origins By Dr. Pankaj Dhussa
NASA SPHEREx Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer Mapping the sky to investigate Cosmic Origins
- 1. SPHEREx Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer Where do water and other key ingredients for life originate in our galaxy, and why does the universe look the way it does? To answer big questions like these, scientists need to look at the big picture. NASA’s SPHEREx will produce a 3D map of the entire sky, providing a wide perspective that can complement the work of telescopes that observe smaller sections of the sky in more detail, such as NASA’s James Webb and Hubble. SPHEREx will use a technique called spectroscopy to view the sky in 102 distinct wavelengths, or colors, of infrared light. Spectroscopy is used to measure the distances to galaxies, so it’s essential for mapping the sky in 3D. The technique can also reveal the composition of cosmic objects, because chemical elements, molecules, and other materials leave a unique signature in the colors they absorb and emit. The mission will use this capability to study the origins of our universe, of galaxies, and of water and other ingredients for life in our galaxy. Mission Timeline • Early 2025: SPHEREx launches from Vandenberg Space Force Base in California on a Falcon 9 rocket from Mapping the Sky to Investigate Cosmic Origins Key Objectives • Create an all-sky spectral map containing data on hundreds of millions of stars and galaxies that will be available to scientists around the world. • Study inflation, the cosmic phenomenon that caused space itself to expand in size by a trillion-trillionfold in a fraction of a second after the big bang. SPHEREx will measure inflation’s subtle effect on the 3D distribution of hundreds of millions of galaxies. • Measure the collective glow from galaxies near and far, including from galaxies so small or faint that they tend to evade detection. This will complement previous efforts to estimate the total amount of light galaxies have produced over cosmic history. • Search the Milky Way galaxy for water, carbon dioxide, and other basic ingredients necessary for life as we know it frozen on dust grains in interstellar clouds. Research suggests most of the water in the universe can be found in these cosmic coolers, including water that could eventually form oceans on distant planets and moons. SPHEREx will reveal more about how different environments affect the chemistry of these icy compounds. Top: NASA’s SPHEREx depicted in an artist’s concept. Credit: NASA/JPL-Caltech Space Launch Complex 4 East, followed by a 30-day in-orbit checkout phase. • Two years: Duration of prime mission, during which SPHEREx will complete four all-sky maps. Data will be continuously released within two months of collection, and images and catalogs from the all-sky maps will be released periodically throughout the mission.
- 2. NASA Facts www.nasa.gov National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Science Instrument: Telescope • The SPHEREx telescope has three mirrors, an effective diameter of 7.9 inches (20 centimeters), and a field of view that is 11 by 3.5 degrees. The telescope directs the light it collects to a pair of focal-plane assemblies, each containing three infrared detectors topped with color filters. Each filter contains 17 color bands, for a total of 102 colors across all six detectors. • The telescope will observe a given point in the sky in one of the 17 color bands. The spacecraft will then shift position slightly so that the same point moves into a different color band, repeating this process across all 6 detectors until every section of the sky has been imaged in all 102 color bands. A similar approach is used in planetary science to rapidly conduct spectroscopy across the surface of planets and moons. SPHEREx Spacecraft • Observatory total size: 8.5 feet (2.6 meters) tall, 10.5 feet (3.2 meters) in diameter at its widest point, 1,107 pounds (502 kilograms). • Photon shields: Three aluminum concentric cones, each 5.6 feet (1.7 meters) tall, with the widest being 10.5 feet (3.2 meters) in diameter. These surround the observatory’s telescope and detectors, which need to operate at around minus 350 degrees Fahrenheit (about minus 210 degrees Celsius). The low temperature prevents the telescope and detectors from glowing in the infrared and potentially overwhelming observations of faint cosmic sources. • Cooling system: The cooling system that enables the spacecraft to reach the low temperatures required for observation is entirely passive, without a mechanical cooler or stored coolants. Key components include the photon shields and a mirrored structure beneath the shields called a v-groove radiator that directs heat from the instrument out into space. • Spacecraft bus: Sitting below the photon shields, the bus contains the observatory’s main computer, along with equipment for communicating with Earth and controlling the spacecraft’s orientation. • Solar panel: Attached to the spacecraft bus, the single panel measures 8.75 feet by 3.4 feet (2.67 meters by 1.02 meters) and produces 750 watts of power (about what’s needed to run a standard refrigerator). • Orbit: In its Sun-synchronous orbit over Earth’s poles, the spacecraft will remain at Earth’s day-night line (or terminator), keeping the telescope pointed at least 91 degrees away from the Sun and at least 140 degrees away from Earth, both significant sources of infrared light and heat. Mission Partners SPHEREx is managed by NASA’s Jet Propulsion Laboratory for the agency’s Astrophysics Division within the Science Mission Directorate in Washington. BAE Systems built the telescope and the spacecraft bus. The science analysis of SPHEREx data will be conducted by a team of scientists at 10 institutions across the U.S. and in South Korea. Data will be processed and archived at IPAC at Caltech in Pasadena, California. The SPHEREx dataset will be publicly available at the NASA/IPAC Infrared Science Archive. Caltech manages JPL for NASA. Mission Website For more information about the SPHEREx mission, visit: https://science.nasa.gov/mission/spherex/ NASA’s SPHEREx is oriented in a horizontal position, revealing all three layers of photon shields as well as the telescope. Credit: NASA/JPL-Caltech/BAE Systems