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NASA has decided to launch the multibillion-dollar Europa Clipper mission on a commercial heavy-lift rocket in October 2024, and not on the government-owned space launch system, officials said on Wednesday.
The decision ends a prolonged dilemma for NASA, which until last year was legally required to launch the Europa Clipper mission on the more expensive space launch system. Wording adopted in previous NASA appropriation bills ordered NASA to launch the SLS rocket investigation, but Congress caved in during the FY2021 spending bill passed in December. .
Lawmakers gave NASA some flexibility over the launcher’s decision in the 2021 budget, ordering the agency to launch Europa Clipper on the space launch system only if the rocket is available, and if “if Torsional load analysis confirmed Clipper’s suitability for SLS. “
Last year, Europa Clipper officials raised concerns about the spacecraft’s compatibility with the space launch system due to the structural loads the probe will encounter during an SLS launch. NASA officials said last year that a rocket from the space launch system will not be available for Europa Clipper launch until 2025 due to the commitment to use SLS rockets on Artemis lunar missions of the agency.
If Europa Clipper was forced to launch on an SLS rocket, NASA would likely have to store the spacecraft to await the launcher’s availability, NASA officials said. And an SLS launch would cost up to $ 1.5 billion more than launching Europa Clipper on a commercial rocket, according to the space agency.
The flexibility offered in the language of the 2021 budget has given NASA the green light to finally move forward with a purchase of commercial rockets for Europa Clipper.
Bob Pappalardo, the Europa Clipper project scientist at the Jet Propulsion Laboratory, said on Wednesday that NASA officials on January 25 ordered Clipper’s team to work on the launch of the spacecraft on a commercial rocket. Engineers previously designed the spacecraft to be able to be launched on an SLS or commercial booster, resulting in additional work and costs, and delaying the critical review of the Europa Clipper design, a milestone in which the design of the spaceship is frozen.
“We now have clarification on the trajectory of the launcher and the launch date,” Pappalardo said Wednesday at a meeting of NASA’s Outer Planets Assessment Group. “We received instructions at the end of January from the Planetary Missions Program office to limit ourselves to a single path of launchers. We received a memo directing the project to “immediately cease efforts to maintain SLS compatibility and move forward with a CLV, a commercial launcher”.
Launching the Europa Clipper mission on the more powerful space launch system would give the spacecraft extra speed as it leaves Earth, allowing direct travel to Jupiter with a transit time of around two and a half to three years.
With a commercial rocket, like SpaceX’s Falcon Heavy, the spacecraft will have to use gravity-assisted maneuvers, or overflights, with Mars and Earth to gain enough speed to launch into the outer solar system. This will increase the travel time to five and a half years between launch and arrival at Jupiter.
The Europa Clipper mission has a planetary launch window in 2024 that opens on October 10 and ends on October 30, based on a trajectory calculated by NASA that assumes a launch on a commercial rocket. The spacecraft would leave Earth on a trajectory to meet Mars on February 28, 2025, then return to Earth for a second gravity-assisted flyby on December 2, 2026, putting Clipper on a trajectory to orbit Jupiter on April 11, 2030.
Save launch windows are available for Europa Clipper in 2025 and 2026, with an arrival in Jupiter later in the 2030s.
The longer flight time to Jupiter will increase the operating budget of Europa Clipper, but those costs will be more than offset by the savings from the launch of a cheaper commercial rocket.
Jan Chodas, Europa Clipper project manager at JPL, said the decision to go with a commercial rocket “definitely helps the team from the point of view of not having to haul a lot of dual paths with SLS and a CLV. , so there are cost savings. . “
She said there was also an “efficiency gain” for the Europa Clipper team because scientists and engineers can move forward without having to duplicate work for SLS and commercial launch alternatives. Chodas said NASA’s Kennedy Space Center Launch Services Program in Florida will oversee the launch vehicle procurement efforts, which will result in a rocket selection “in about a year.”
The launch services program will run a “full and open competition to select the Clipper launch vehicle,” said Curt Niebur, NASA’s program scientist for missions to the outer planets. “This competition is starting.”
NASA issued a request for information on January 26, seeking responses from US-based commercial launcher suppliers on their capabilities to launch Europa Clipper. The mission is part of NASA’s flagship class of interplanetary probes, with a cost commitment of $ 4.25 billion.
Along with the multibillion dollar cost of Europa Clipper comes the need to launch the spacecraft on a reliable rocket. NASA said in its Jan. 26 request for information that the selected launch provider for Europa Clipper must perform at least three successful flights of the same launcher configuration proposed for Clipper before the mission takes off in October 2024, with at least two consecutive successful launches. .
The Europa Clipper spacecraft is expected to weigh over 13,000 pounds, or at least 6,065 kilograms, with fuel loaded for the trip to Jupiter.
The mass of the spacecraft, coupled with the need for a high-speed departure from Earth, means SpaceX’s Falcon Heavy rocket is the only launcher expected to be available in 2024, and also currently operational, that could accommodate the mission. Europa Clipper. This likely assumes SpaceX will spend the Falcon Heavy’s first stage boosters, dedicating all of the rocket’s performance to launch and leaving no thruster to recover the stages.
After entering orbit around Jupiter, Europa Clipper will proceed on a course to perform approximately 45 close overflights with Europa, passing as close as 16 miles, or 25 kilometers, to the frozen moon. Equipped with large solar panels to generate electricity, the spacecraft will take a slightly different path through Europa on each pass, eventually surveying almost the entire moon with observations from its nine scientific instruments.
Europe is covered with a global ice cap that covers an ocean of liquid water, providing an environment that could be habitable for life. Clipper’s instruments will take high-resolution images and map the composition and topography of Europe’s ice shell. The probe will carry radar to bounce radio waves off the inside of Europa to determine the thickness and deep structure of the ice caps, and Clipper will look for evidence of eruptions of water passing through cracks in the ice, which could provide a window on the environment. of the liquid ocean below.
Pappalardo said the Europa Clipper mission completed its critical design review in December. The review committee identified cost issues related to the mission development and operations plans and the launcher decision as key issues facing the Clipper team. But NASA’s decision to go with a commercial rocket ultimately alleviates that concern, Pappalardo said.
“The whole project continues to make great technical progress despite the impacts of COVID-19,” Pappalardo said.
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Follow Stephen Clark on Twitter: @ StephenClark1.
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