Space Telescope SPHEREx Begins Initial Operations After Successful Launch
NASA's latest astrophysics observatory, SPHEREx, has officially embarked on its mission to explore the origins of the universe, trace the history of galaxies, and search for the building blocks of life within our Milky Way. The Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx) lifted off at 8:10 p.m. PDT on March 11, riding aboard a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.
Accompanying SPHEREx on the Falcon 9 were four small satellites comprising NASA's PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission, which will study how the Sun's outer atmosphere transitions into the solar wind that flows throughout the solar system.
"Everything in NASA science is interconnected, and sending both SPHEREx and PUNCH up on a single rocket doubles the opportunities to do incredible science in space", said Nicky Fox, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. "Congratulations to both mission teams as they explore the cosmos from distant galaxies to our neighborhood star. I am excited to see the data returned in the years to come".
Ground controllers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, which manages SPHEREx, established communication with the space observatory at 9:31 p.m. PDT. The spacecraft will undergo a one-month checkout period to ensure all systems are functioning correctly before commencing its two-year prime mission.
“The fact our amazing SPHEREx team kept this mission on track even as the Southern California wildfires swept through our community is a testament to their remarkable commitment to deepening humanity’s understanding of our universe,” said Laurie Leshin, director of NASA JPL. “We now eagerly await the scientific breakthroughs from SPHEREx’s all-sky survey including insights into how the universe began and where the ingredients of life reside”.
Meanwhile, the four PUNCH satellites separated from the Falcon 9 approximately 53 minutes after launch. Ground controllers successfully established contact with all four spacecraft, which will now enter a 90-day commissioning phase. During this period, the satellites will align into their operational formation, and their instruments will be calibrated to function as a single virtual instrument, ready to capture detailed images of the solar wind.
Both SPHEREx and PUNCH are designed to operate in low Earth, Sun-synchronous orbits, flying along the planet’s day-night line also known as the terminator. This ensures the Sun remains in a constant position relative to the spacecraft, essential for SPHEREx to keep its telescope shielded from direct sunlight and for PUNCH to maintain a clear, uninterrupted view of the Sun and its surroundings.
SPHEREx’s mission is ambitious. It will create a 3D map of the entire celestial sky every six months, offering a broad perspective that complements the detailed observations of other telescopes, such as NASA’s James Webb and Hubble Space Telescopes. By using a technique called spectroscopy, SPHEREx will measure the distance to 450 million galaxies, revealing how their large-scale distribution was influenced by cosmic inflation — an event that caused the universe to expand exponentially in a fraction of a second after the big bang nearly 14 billion years ago.
In addition to exploring the early universe, SPHEREx will measure the collective glow of all galaxies to better understand how they evolved over cosmic time. The telescope will also survey the Milky Way for hidden reservoirs of frozen water and other life-essential molecules, such as carbon dioxide, that may reside on interstellar dust grains and in distant planetary systems.
“Questions like ‘How did we get here?’ and ‘Are we alone?’ have been asked by humans for all of history,” said James Fanson, SPHEREx project manager at JPL. “I think it’s incredible that we are alive at a time when we have the scientific tools to actually start to answer them”.
Meanwhile, the PUNCH mission will make global, 3D observations of the Sun’s outer atmosphere, the corona, and how it gives rise to the solar wind a continuous flow of charged particles that fills the solar system. By studying the formation and evolution of space weather events, such as coronal mass ejections, PUNCH aims to better understand phenomena that can create hazardous radiation storms capable of damaging satellites and endangering astronauts.
“The space between planets is not an empty void. It’s full of turbulent solar wind that washes over Earth”, said Craig DeForest, PUNCH’s principal investigator at the Southwest Research Institute. “The PUNCH mission is designed to answer basic questions about how stars like our Sun produce stellar winds, and how they give rise to dangerous space weather events right here on Earth”.
Together, SPHEREx and PUNCH promise to deliver groundbreaking insights into both the distant cosmos and the dynamic environment of our solar system. As these missions begin their scientific journeys, they hold the potential to reshape our understanding of the universe and humanity’s place within it.
