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The Europa Clipper sports the largest solar arrays ever flown on a planetary probe: Each wing measures about 46.5 ft. long and 13.5 ft. wide. The deployment mechanism was tested at Kennedy Space Center in August. Launch is targeted for Oct. 10.
NASA has resolved concerns about whether transistors aboard its Europa Clipper spacecraft can survive the harsh radiation environment of Jupiter, clearing the mission to proceed to launch.
Liftoff aboard a SpaceX Falcon Heavy rocket is targeted between Oct. 10 and Nov. 6 from Kennedy Space Center, with arrival at Jupiter expected in April 2030. The mission aims to assess if Europa, one of Jupiter’s ocean-bearing moons, is suitable to support life.
NASA and Europa Clipper suppliers and contractors spent much of the summer analyzing if industry-standard radiation-hardened transistors, which are located throughout the spacecraft, would withstand the operating environment at Jupiter. The concern was raised in May following the discovery that similar transistors were failing at lower radiation levels than expected.
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To resist Jupiter’s intense radiation, Europa Clipper’s critical sophisticated electronics are sealed in a 0.5-in.-thick aluminum-zinc alloy walled vault. Functioning as electrical switches, the radiation-hardened transistors on the spacecraft are intended to tolerate 100-300 kilorads of ionizing radiation.
Jupiter, the Solar System’s largest planet, generates a magnetic field that traps and accelerates charged electrical particles. It is 20,000 times stronger than that of Earth. The activity creates intense radiation at Europa and Jupiter’s other inner moons. Europa is the fourth largest of Jupiter’s 95 known moons and the sixth closest to the planet.
The spacecraft will retain its original flight plan, which includes 49 flybys of Europa and 80 orbits of Jupiter over the four-year primary science mission. Clipper will travel as close as 16 mi. from Europa’s surface while its instruments collect data to reveal the location and depth of what is believed to be a large saltwater ocean beneath the moon’s frozen surface. Clipper also will assess chemicals that are on Europa’s surface, including materials that may have been deposited by geysers shooting up from the liquid ocean beneath.
The mission’s goal is to assess if Europa has the environments and conditions that could support life (AW&ST June 3-16).
The spacecraft will be launched on a SpaceX Falcon Heavy rocket, flown in a fully expendable configuration with all booster recovery hardware removed. That will allow the upper stage to reach speeds of 25,000 mph—the fastest speed for a Falcon upper stage.
SpaceX recently made some hardware modifications that will enable the booster to use all of its fuel, a performance enhancement that will allow for a launch attempt as late as Nov. 6—a week beyond the previously planned close of the 2024 launch window. NASA’s Launch Services Program Mission Manager Armando Piloto said details of the enhancements are proprietary.
“Our original launch date window ended on Oct. 30, but we’ve been able to extend it based on some additional performance that SpaceX was able to squeeze out of the launch vehicle,” Piloto said during a Sept. 17 mission status briefing with reporters. “This is SpaceX’s 11th flight of the Falcon Heavy, and they’ve come up with a strategy to optimize the throttling of the launch vehicle to get the most performance out of it.”
In addition, SpaceX will use NASA’s Tracking and Data Relay Satellites to receive telemetry from the rocket, rather than having to overfly ground stations. The switch allows for a more optimized trajectory. “That gave us a lot of additional performance as well,” Piloto said.
NASA completed fueling Europa Clipper with 6,068 lb. of propellant on Sept. 22. The propellant will be used by the spacecraft’s 24 engines to adjust its flightpath to and around Jupiter. The Clipper is due to be encapsulated and then transported to Kennedy Space Center Launch Complex 39A around Oct. 4.
Launch is targeted for 12:31 p.m. EDT Oct. 10. Each day’s launch window is instantaneous. If the Falcon Heavy is fueled for a launch attempt and does not fly due to weather or a minor technical issue, SpaceX will need a 48-hr. turnaround, Piloto said.
The Falcon Heavy’s upper stage should release the Clipper at an altitude of 2,032 mi. from Earth. The spacecraft is to fly by Mars in February 2025, then swing back around Earth in December 2026, using the planets’ gravities to pick up speed to reach Jupiter in April 2030.
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