NASA has decided to launch the multi-billion-dollar Europa Clipper mission on a heavy commercial rocket in October 2024, rather than on the government-owned Space Launch System, officials said Wednesday.
The decision ends a protracted dilemma for NASA, which until last year was legally required to launch the Europa Clipper mission on its more expensive Space Launch System. Language passed in previous NASA bills directed NASA to launch a probe on an SLS missile, but Congress backtracked on the 2021 fiscal year spending bill that passed in December.
Lawmakers gave NASA some flexibility over the launch vehicle decision in the fiscal year 2021 budget, directing the agency to launch the Europa Clipper on the Space Launch System only if the missile was available, and if torsional loading analysis confirmed the Clipper’s suitability for the SLS. “
Europa Clipper managers last year raised concerns about the spacecraft’s compatibility with the Space Launch System due to the structural loads the probe will encounter while launching the SLS. NASA officials said last year that the Space Launch System missile will not be available to launch the Europa Clipper until 2025 due to commitments to use SLS missiles in the agency’s Artemis moon missions.
NASA officials said that if the Europa Clipper were ever forced to launch an SLS missile, NASA would likely have to put the spacecraft in storage to wait for a launcher to become available. According to the space agency, launching an SLS would cost up to $ 1.5 billion more than launching a Europa Clipper on a commercial rocket.
The flexibility provided in 2021 budget language gave NASA the green light to finally go ahead with the purchase of a commercial rocket for Europa Clipper.
Bob Pappalardo, a Europa Clipper project scientist at the Jet Propulsion Laboratory, said Wednesday that on January 25, NASA managers directed the Clipper team to work toward launching a spacecraft at a commercial rocket. Engineers had previously designed the spacecraft to be capable of launching on an SLS or commercial booster, which resulted in additional work, additional costs, and delays in a critical design review for the Europa Clipper, a milestone in which the spacecraft’s design was frozen.
“We now have clarity on the path of the launch vehicle and the launch date,” Pappalardo said on Wednesday at a meeting of the NASA Exoplanet Assessment Group. “We received a directive in late January from the Planetary Missions Program Office to complete a unique path for the launch vehicle. We received a memorandum directing the project to“ immediately halt efforts to maintain SLS compliance and to proceed with the CLV, a commercial launch vehicle. ”
Launching the Europa Clipper mission on the more powerful space launch system will give the spacecraft an additional boost of speed as it leaves Earth, enabling a direct flight to Jupiter with a transit time of two and a half to three years.
Using a commercial rocket, such as SpaceX’s Falcon Heavy, the spacecraft would have to use gravitational assist maneuvers, or flyovers, with Mars and Earth to gain sufficient velocity to be ejected into the outer solar system. This would increase the travel time to five and a half years from launch to 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 launch on a commercial rocket. The spacecraft will leave Earth on a path to encounter Mars on February 28, 2025, and then return to Earth for a second flyby with the help of gravity on December 2, 2026, putting Clipper on a path to enter orbit around Jupiter on April 11, 2030.
There are backup operating windows available for the Europa Clipper in 2025 and 2026, with Jupiter arriving later in 2030.
Longer flight time to Jupiter would add to the Europa Clipper operations budget, but these costs would be offset by the savings from launching on a less expensive commercial rocket.
The decision to go with a commercial missile “definitely helps the team from the standpoint of not having to carry too many dual tracks with the SLS and CLV, so there are cost savings there,” said Jan Choudas, Project Manager for Europa Clipper at JPL.
There are also “efficiency gains” for the Europa Clipper team, she said, because scientists and engineers can move forward without having to duplicate SLS and commercial launch alternatives. Choudas said the Launch Services Program at NASA’s Kennedy Space Center in Florida will oversee efforts to purchase a launcher, resulting in a missile being selected “within a year or so.”
The launch services program will run “a complete and open competition for the selection of the launch vehicle for the Clipper,” said Curt Niebuhr, NASA’s program scientist for missions to exoplanets. “This competition has started.”
NASA issued a request for a media notice on January 26 requesting responses from commercial launch providers in the United States regarding their capabilities to launch the Europa Clipper. The mission is in NASA’s flagship class of interplanetary probes, at a cost of $ 4.25 billion.
The Europa Clipper’s multi-billion dollar cost comes with the condition that the spacecraft launch on a reliable rocket. NASA said in its January 26 request for information that the launch provider chosen for the Europa Clipper must make at least three successful flights of the same configuration as the proposed launch vehicle for the Clipper before the mission launches in October 2024, with at least two consecutive successful launches.
The Europa Clipper spacecraft is expected to weigh more than 13,000 pounds, or no less than 6,065 kg, with fuel loaded for the trip to Jupiter.
The spacecraft’s mass, along with requirements for high-speed departure from Earth, means SpaceX’s Falcon Heavy rocket is the only launch vehicle expected to be available in 2024, also currently in operation, that can accommodate the Europa Clipper mission. This presumably presumes that SpaceX is spending Falcon Heavy first stage boosters, dedicating all rocket performance to launch, leaving no impulse to recover phases.
After entering orbit around Jupiter, the Europa Clipper will head onto a trajectory for about 45 flights close by with Europa, passing approximately 16 miles, or 25 kilometers, from the icy moon. The spacecraft, equipped with large solar arrays to generate electricity, will take a slightly different path through Europe in each lane, and will eventually scan nearly the entire moon through observations from its nine scientific instruments.
Europa is covered with a global ice sheet and cocoons of an ocean of liquid water, providing an environment that may be habitable for life. The Clipper tools will capture high-resolution images and map the composition and terrain of the ice sheet in Europe. The probe will carry a radar to bounce radio waves from within Europe to determine the thickness and structure of deep ice sheets, and Clipper will search for evidence of water eruption coming through cracks in the ice, which may provide a window into the environment from the liquid ocean below.
Pappalardo said the Europa Clipper mission completed a critical design review in December. The review board identified cost concerns with the mission’s development plans and operations, and launch vehicle decision as major issues facing the Clipper team. But Pappalardo said NASA’s decision to use a commercial missile finally relieves that concern.
“The whole project continues to make significant technical progress despite the impacts of COVID-19,” Pappalardo said.
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