After more than a week of delays, two new NASA missions have been cleared for liftoff tonight (March 8).
The space agency’s SPHEREx and PUNCH missions, which are sharing a ride aboard the SpaceX Falcon 9 rocket, are scheduled to lift off no earlier than 10:09 p.m. EST (7:09 p.m. PST) tonight from Launch Complex 4E at Vandenberg Space Force Base in California. The launch, postponed six times over the past week due to technical issues and bad weather, was given the greenlight after a successful launch readiness review on Friday (March 7) by launch managers from NASA’s Launch Services Program and SpaceX.
“We’ve run into a lot of challenges along the way (that) have caused us some launch delays, but this team has pulled together and worked diligently to get us over that,” Denton Gibson, the launch director of NASA’s Launch Services Program, told reporters during a pre-launch briefing on Friday. “We made sure that we successfully passed all these challenges that we had to deal with, and we’re ready to go.”
The weeklong launch slips were primarily due to a series of technical issues that arose during spacecraft integration, particularly with a system designed to mitigate the environmental stresses the spacecraft experiences during ascent, said Julianna Scheiman, director of NASA science missions at SpaceX. The issue required the team to install updated fasteners to replace inserts within the system that had become problematically ovalized, she said.
The team also needed to repair a leak in the fairing’s pneumatic system, said Scheiman, referring to a system that maintains sufficient pressure in order to separate the fairing surrounding the spacecraft into two halves during flight, allowing them to fall back to Earth. Other delays surrounded bad weather present while teams were transporting the spacecraft to the launch site and a stand-down required to support a government high-priority range operation, Scheiman said.
The launch readiness review on Friday, which authorized the missions for launch ahead of what’s supposed to be clear weather, came after SpaceX addressed the technical issues, followed by an independent evaluation by NASA, said Gibson. “We’ve gone through that process and we’ve gotten comfortable with where we are,” he said, “which is why we were able to successfully complete our launch readiness review.”
The megaphone-shaped SPHEREx — short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer — is designed to map the entire sky in 3D, in wavelengths invisible to the human eye. The two-year, $488-million effort aims to capture a broad view of more than 450 million galaxies and over 100 million stars in our home galaxy, the Milky Way. By creating a comprehensive catalog of these objects in more than 100 infrared colors, scientists hope to answer fundamental questions about the origin of the universe, the galaxies within and life’s essential ingredients that scientists say can only be addressed by examining the universe from a wide, all-encompassing perspective.
The spacecraft is sharing its ride to space with NASA’s $150-million PUNCH (short for Polarimeter to Unify the Corona and Heliosphere) mission, which is a constellation of four suitcase-sized satellites designed to study our sun. This mission aims to understand how the solar wind is driven by eruptions on the sun, and capture 3D images of the sun’s wispy, blisteringly hot outer atmosphere as it transitions into the solar wind. One of the four satellites is equipped with a sun-blocking coronagraph, while the other three are designed to measure the faint solar wind. Together, the quartet will function as one instrument to make global, 3D observations of the entire inner heliosphere.
If all goes to plan, the spacecraft for both missions will separate from Falcon 9 within an hour after launch — SPHEREx will deploy first, about 42 minutes after liftoff, followed by PUNCH about 10 minutes later. Meanwhile, the rocket’s reusable first stage is expected to make an automated return to the launch site eight minutes after liftoff. “For those in the area, make sure you keep your ears open for the thunder of the sonic booms,” said Scheiman.
The first hour after launch is a crucial time for ground controllers at NASA’s Jet Propulsion Laboratory, who will seek to establish communications with the spacecraft and assess the health of their instruments. The first of several opportunities for the SPHEREx team will occur within the first three minutes after spacecraft separation, as the probe passes over Antarctica as part of its polar orbit around Earth. Subsequent opportunities will take place within the next 45 minutes as the spacecraft flies over Svalbard in the Arctic, followed by another opportunity about 20 minutes later as it passes over Fairbanks, Alaska.
SPHEREx has a single solar panel that will almost always face the sunbut is also capable of operating on battery power alone for several hours if needed, said James Fanson, the SPHEREx project manager at NASA’s Jet Propulsion Laboratory. In the coming days, the spacecraft should eject the protective cover over its telescope lens, or “lens cap,” and outgas moisture and other contaminants, he said. If all goes according to plan, the observatory will begin its highly anticipated science survey just over a month from now, once the telescope has cooled to its operating temperature and the mission team has completed a series of checks, including powering on the spacecraft’s imaging sensors to collect engineering data for calibration.
The PUNCH satellites will go through similar checks soon after launch, followed by a three-month commissioning period during which three satellites will position themselves around Earth into the designed formation around the center, coronagraph-equipped satellite — an arrangement necessary for the satellites to function as a single instrument for gathering the planned observations.
Once in orbit, both missions are expected to collect science data for at least two years, possibly more.
“Liftoff is just the beginning,” said Fanson.
