NASA launches missions to study Sun, Universe's beginning

NASA's newest astrophysics observatory, SPHEREx, is on its way to study the origins of our universe and the history of galaxies and to search for the ingredients of life in our galaxy. Short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, SPHEREx lifted off at 8:10 p.m. PDT on 11 March aboard a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.

Four small satellites, which make up the agency's PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission, rode with SPHEREx aboard the Falcon 9. The mission will study how the Sun's outer atmosphere becomes the solar wind.

"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, Science Mission Directorate at NASA Headquarters in Washington. "Congratulations to both mission teams as they explore the cosmos from far-out 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 in Southern California, which manages SPHEREx, established communications with the space observatory at 9:31 p.m. PDT. After a roughly one-month checkout period, the observatory will begin its two-year prime mission.

The PUNCH satellites successfully separated about 53 minutes after launch, and ground controllers established communication with all four spacecraft. Now, PUNCH begins a 90-day commissioning period during which the four satellites will enter the correct orbital formation. The instruments will be calibrated as a single 'virtual instrument' before the scientists start analyzing images of the solar wind.

The two missions are designed to operate in a low Earth, Sun-synchronous orbit over the day-night line (also known as the terminator) so the Sun always remains in the same position relative to the spacecraft. This is essential for SPHEREx to keep its telescope shielded from the Sun's light and heat (both would inhibit its observations) and for PUNCH to have a clear view in all directions around the Sun.

To achieve its goals, SPHEREx will create a 3D map of the entire celestial sky every six months, providing a broad perspective to complement the work of space telescopes that observe smaller sections of the sky in more detail, such as NASA's James Webb Space Telescope and Hubble Space Telescope.

The mission will use spectroscopy to measure the distance to 450 million galaxies in the nearby universe. Their large-scale distribution was subtly influenced by an event that took place almost 14 billion years ago, known as inflation. This event caused the universe to expand in size a trillion trillionfold in a fraction of a second after the Big Bang. The mission also will measure the total collective glow of all the galaxies in the universe, providing new insights into how galaxies have formed and evolved over cosmic time.

Spectroscopy can also reveal the composition of cosmic objects. SPHEREx will survey our home galaxy for hidden reservoirs of frozen water ice and other molecules, like carbon dioxide, that are essential to life as we know it.

NASA's PUNCH will make global, 3D observations of the inner solar system and the Sun's outer atmosphere, the corona, to learn how its mass and energy become the solar wind, a stream of charged particles blowing outward from the Sun in all directions. The mission will explore the formation and evolution of space weather events such as coronal mass ejections, which can create storms of energetic particle radiation that can endanger spacecraft and astronauts.

"The space between planets is not an empty void. It's full of turbulent solar wind that washes over Earth," said Craig DeForest, the mission'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."

More about SPHEREx, PUNCH

NASA JPL manages the SPHEREx mission for the agency's Astrophysics Division within the Science Mission Directorate at NASA Headquarters. BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at ten institutions in the U.S., two in South Korea and one in Taiwan. Data will be processed and archived at IPAC at Caltech, which manages JPL for NASA. The mission's principal investigator is based at Caltech with a joint JPL appointment. The SPHEREx dataset will be publicly available at the NASA-IPAC Infrared Science Archive.

Southwest Research Institute (SwRI) leads the PUNCH mission and built the four spacecraft and Wide Field Imager instruments at its San Antonio, Texas headquarters. The Narrow Field Imager instrument was built by the Naval Research Laboratory in Washington. The mission is operated from SwRI's offices in Boulder, Colorado. It is managed by the Explorers Program Office at NASA's Goddard Space Flight Center in Greenbelt, Maryland, for NASA's Science Mission Directorate in Washington.

(article source: NASA / editor: Anton van Rijsbergen)