Important elements are coming together NASAThe SPHEREx mission is a space telescope that will map the universe like never before.
NASA’s SPHEREx space telescope is starting to look much the same as it did when it arrived in Earth orbit and began mapping the entire sky. SPHEREx, which stands for Specto-Photometer for the History of the Universe, Epoch of Reionization, or Ice Explorer, resembles a bullhorn but is approximately 8.5 feet (2.6 meters) tall and approximately 10.5 feet (3.2 meters) wide. there is. The observatory’s characteristic shape is a cone. photon The shield is assembled in a clean room at NASA’s Jet Propulsion Laboratory in Southern California.
shield and operation
The three cones fit into each other and surround SPHEREx’s telescope, protecting it from the light and heat of the Sun and Earth. Like scanning the inside of a globe, the spacecraft combs every part of the sky to complete two maps of the sky each year.
“SPHEREx needs to be very agile because the spacecraft needs to move relatively quickly as it scans the sky,” he said. JPLSarah Saska is the mission’s deputy payload manager and payload systems engineer. “Although it doesn’t seem like it, the shield is actually very light and is made of sandwich-like layers of material. The outside is a sheet of aluminum and the inside is a cardboard-like aluminum honeycomb structure, making it light and easy to use. It’s strong.”
NASA’s SPHEREx creates maps of the sky like no other. Check out some of the special hardware the mission uses to perform cutting-edge science.Credit: NASA/JPL-California Institute of Technology
mission objective
SPHEREx will begin no later than April 2025 and will help scientists better understand where water and other critical components necessary for life come from. To do this, the mission will measure the amount of water ice in the gas and dust of interstellar clouds from which new stars are born and, ultimately, planets form. We will study the cosmic history of galaxies by measuring the collective light they produce. These measurements help reveal when galaxies began to form and how their formation has changed over time. Finally, by mapping the positions of millions of galaxies against each other, SPHEREx will look for new clues about how the rapid expansion of the universe, or inflation, occurred seconds after the Big Bang.
cool and stable
SPHEREx does all this by detecting infrared light, a wavelength range longer than visible light that the human eye can see. Infrared radiation is also called thermal radiation because all warm objects emit it. Telescopes can also produce infrared light. That light interferes with the detector, so the telescope must be kept below -350 degrees. Fahrenheit (approximately minus 210 degrees Celsius).
The outer photon shield blocks light and heat from the Sun and Earth, and the gap between the cones prevents heat from traveling inward toward the telescope. But to ensure that the SPHEREx gets down to frigid operating temperatures, it also requires something called a V-groove radiator. This is a stack of three conical mirrors that look like upside-down umbrellas. Each shield below the Photon Shield consists of a series of wedges that redirect infrared light, allowing it to bounce back through gaps between the shields and out into space. This removes heat carried through the supports from the room-temperature spacecraft bus containing computers and electronics.
“We’re concerned not only about how cold SPHEREx is, but also that its temperature won’t change,” said Konstantin Penanen, JPL’s mission payload manager. “As the temperature changes, the sensitivity of the detector can change, which can be interpreted as a false signal.”
eye on the sky
The centerpiece of SPHEREx is, of course, the telescope, which uses three mirrors and six detectors to collect infrared light from distant sources. The telescope is tilted at its base so that it can see as much of the sky as possible while remaining within the protection of the photon shield.
The telescope, built by Ball Aerospace in Boulder, Colorado, arrived at the California Institute of Technology in Pasadena, California, in May and has an integrated detector and V-groove emitter. Then, at JPL, engineers secured the telescope to a shaking table that simulates the shaking it endures during a rocket trip to space. Later, back at Caltech, scientists confirmed that the mirror remained in focus after vibration tests.
SPHEREx’s infrared “vision”
Mirrors in SPHEREx’s telescope collect light from distant objects, but it’s the detectors that can “see” the infrared wavelengths the mission is trying to observe.
Stars like our Sun are white because they emit the full range of visible wavelengths (although Earth’s atmosphere makes them white). looks more yellow to our eyes). The prism splits the light into its component wavelengths, or rainbows. This is called spectroscopy.
SPHEREx performs spectroscopic analysis using a filter mounted on top of the detector. Each filter, about the size of a cracker, appears rainbow-colored to the naked eye and has multiple segments that block all infrared radiation except for certain wavelengths. Every object SPHEREx observes will be imaged by each segment, allowing scientists to see the specific infrared wavelengths emitted by that object, whether it’s a star or a galaxy. In total, this telescope allows him to observe over 100 different wavelengths.
And from there, SPHEREx will map the universe like never before.
NASA’s SPHEREx mission
SPHEREx is managed by the Jet Propulsion Laboratory (JPL) of NASA’s Astrophysics Division within the Science Mission Directorate in Washington. Ball Aerospace will manufacture the telescope and supply the spacecraft bus. Scientific analysis of SPHEREx data will be performed by a team of scientists from 10 institutions in the United States and South Korea. Data will be processed and archived at Caltech’s IPAC. SPHEREx datasets are publicly available.