Europa Clipper (previously known as the Europa Multiple Flyby Mission) is a mission to send a space probe developed by NASA to study Europa, a Galilean moon of Jupiter. Launched by a Falcon Heavy on October 14, 2024, the probe is planned to enter Jupiter orbit in April 2030 and conduct a series of flybys of Europa from March 2031. Europa Clipper is the largest interplanetary spacecraft ever launched by NASA. The mission used a gravity assist from Mars in March 2025, and will use an assist from Earth in December 2026.
Europa Clipper will investigate the subsurface ocean below Europa's ice crust, found by the Galileo spacecraft which orbited Jupiter from 1995 to 2003. Cancelled Europa missions Europa Orbiter and Jupiter Icy Moons Orbiter called for orbiting the moon. However, Europa's vicinity experiences extreme radiation, being deep within the magnetosphere of Jupiter. Thus Europa Clipper will enter an elliptical orbit around Jupiter via a gravity assist from Jupiter's largest moon Ganymede, and make 49 close flybys of the moon. At its mission end, planned for 2034 or later, it will be intentionally crashed, likely into Ganymede, to prevent forward contamination of Europa.
The orbiter aims to analyze the induced magnetic field around Europa. Its Surface Dust Analyzer mass spectrometer aims to detect and directly sample the subsurface ocean via its water vapor plume ejecta from cryovolcanoes; it is capable of identifying a single bacterium.
The mission's name is a reference to the lightweight, fast clipper ships of the 19th century that routinely plied trade routes, since the spacecraft will pass by Europa at a rapid cadence, as frequently as every two weeks. The mission patch, which depicts a sailing ship, references the moniker. Europa Clipper complements the ESA's Jupiter Icy Moons Explorer, launched in 2023, which will attempt to fly past Europa twice and Callisto multiple times before moving into orbit around Ganymede.
History
Early proposals and Galileo discoveries In 1997, a Europa Orbiter mission was proposed by a team for NASA's Discovery Program but was not selected. NASA's JPL announced one month after the selection of Discovery proposals that a NASA Europa orbiter mission would be conducted. JPL then invited the Discovery proposal team to be the Mission Review Committee (MRC).
At the same time as the proposal of the Discovery-class Europa Orbiter, the robotic Galileo spacecraft was already orbiting Jupiter. From December 8, 1995, to December 7, 1997, Galileo conducted the primary mission after entering the orbit of Jupiter. On that final date, the Galileo orbiter commenced an extended mission known as the Galileo Europa Mission (GEM), which ran until December 31, 1999. This was a low-cost mission extension with a budget of only US$30 million. The smaller team of about 40–50 people (compared with the primary mission's 200-person team from 1995 to 1997) did not have the resources to deal with problems, but when they arose, it was able to temporarily recall former team members (called "tiger teams") for intensive efforts to solve them. The spacecraft made several flybys of Europa (8), Callisto (4) and Io (2). On each flyby of the three moons it encountered, the spacecraft collected only two days' worth of data instead of the seven it had collected during the primary mission. During GEM's eight flybys of Europa, it ranged from , in two years.
Europa has been identified as one of the locations in the Solar System that could possibly harbor microbial extraterrestrial life. Immediately following the Galileo spacecraft's discoveries and the independent Discovery program proposal for a Europa orbiter, JPL conducted preliminary mission studies that envisioned a capable spacecraft such as the Jupiter Icy Moons Orbiter (a US$16 billion mission concept), the Jupiter Europa Orbiter (a US$4.3 billion concept), another orbiter (US$2 billion concept), and a multi-flyby spacecraft: Europa Clipper.
A mission to Europa was recommended by the National Research Council in 2013. The approximate cost estimate rose from US$2 billion in 2013 to US$4.25 billion in 2020.NASA Europa Mission Could Potentially Spot Signs of Alien Life , Mike Wall, Space.com, October 26, 2019 The mission is a joint project between the Johns Hopkins University's Applied Physics Laboratory (APL), and the Jet Propulsion Laboratory (JPL).
Funding put forward In March 2013, US$75 million was authorized to expand on the formulation of mission activities, mature the proposed science goals, and fund preliminary instrument development, as suggested in 2011 by the Planetary Science Decadal Survey. In May 2014, a House bill substantially increased the Europa Clipper (referred to as Europa Multiple Flyby Mission) funding budget for the 2014 fiscal year from US$15 million to US$100 million to be applied to pre-formulation work. Following the 2014 election cycle, bipartisan support was pledged to continue funding for the Europa Multiple Flyby Mission project. The executive branch also granted US$30 million for preliminary studies.
Formulation In April 2015, NASA invited the ESA to submit concepts for an additional probe to fly together with the Europa Clipper spacecraft, with a mass limit of 250 kg. It could be a simple probe, an impactor,Akon – A Penetrator for Europa , Geraint Jones, Geophysical Research Abstracts, Vol. 18, EGU2016-16887, 2016, EGU General Assembly 2016 or a lander. An internal assessment at ESA considered whether there was interest and funds available,Joint Europa Mission (JEM): A multi-scale study of Europa to characterize its habitability and search for life , Michel Blanc, Olga Prieto Ballesteros, Nicolas Andre, and John F. Cooper, Geophysical Research Abstracts, Vol. 19, EGU2017-12931, 2017, EGU General Assembly 2017 opening a collaboration scheme similar to the very successful Cassini–Huygens approach.
In May 2015, NASA chose nine instruments that would fly on board the orbiter, budgeted to cost about US$110 million over the next three years. In June 2015, NASA approved the mission concept, allowing the orbiter to move to its formulation stage. In January 2016, NASA approved the addition of a lander, but this was canceled in 2017 because it was deemed too risky. In May 2016, the Ocean Worlds Exploration Program was approved, of which the Europa mission is part.
In February 2017, the mission moved from Phase A to Phase B (the preliminary design phase). On July 18, 2017, the House Space Subcommittee held hearings on the Europa Clipper as a scheduled Large Strategic Science Missions class, and to discuss a possible follow up mission simply known as the Europa Lander. Phase B continued into 2019. In addition, subsystem vendors were selected, as well as prototype hardware elements for the science instruments. Spacecraft sub-assemblies were built and tested as well.
Fabrication and assembly
On August 19, 2019, the Europa Clipper proceeded to Phase C: final design and fabrication.
On March 3, 2022, the spacecraft moved on to Phase D: assembly, testing, and launch. On June 7, 2022, the main body of the spacecraft was completed. By August 2022, the high-gain antenna had completed its major testing campaigns.
By January 30, 2024, all of the science instruments were added to the spacecraft. In March 2024, it was reported that the spacecraft underwent successful testing and was on track for launch later in the year. In May 2024, the spacecraft arrived at Kennedy Space Center for final launch preparations. In September 2024, final pre-launch review was successfully completed, clearing the way for launch. In early October 2024, due to the incoming Hurricane Milton, the spacecraft was placed in secure storage for safekeeping until the hurricane passed.
Launch In July 2024, the spacecraft faced concerns of delay and missing the launch window because of a discovery in June 2024 that its components were not as radiation-hardened as previously believed. However, over the summer, intensive re-testing of the transistor components in question found that they would likely be annealed enough to 'self-heal'. In September 2024, Europa Clipper was approved for a launch window opening on October 10, 2024; however, on October 6, 2024, NASA announced that it would be standing down from the October 10 launch due to Hurricane Milton. Europa Clipper was finally launched on October 14, 2024.
End of mission planning The probe is scheduled to be crashed into Jupiter, Ganymede, or Callisto, to prevent it from crashing into Europa. In June 2022, lead project scientist Robert Pappalardo revealed that mission planners for Europa Clipper were considering disposing of the probe by crashing it into the surface of Ganymede in case an extended mission was not approved early in the main science phase. He noted that an impact would help the ESA's Juice mission collect more information about Ganymede's surface chemistry. In a 2024 paper, Pappalardo said the mission would last four years in Jupiter orbit, and that disposal was targeted for September 3, 2034 if NASA did not approve a mission extension.
Objectives
The goals of Europa Clipper are to explore Europa, investigate its habitability and aid in the selection of a landing site for the proposed Europa Lander. This exploration is focused on understanding the three main requirements for life: liquid water, chemistry, and energy. Specifically, the objectives are to study:
Ice shell and ocean: Confirm the existence and characterize the nature of water within or beneath the ice, and study processes of surface-ice-ocean exchange. Composition: Distribution and chemistry of key compounds and the links to ocean composition. Geology: Characteristics and formation of surface features, including sites of recent or current activity. The spacecraft carries scientific instruments which will be used to analyze the potential presence of geothermal activity and the moon's induced magnetic field; which in turn will provide an indication to the presence of saline rich subsurface ocean(s).
Strategy
Because Europa lies well within the harsh radiation fields surrounding Jupiter, even a radiation-hardened spacecraft in near orbit would only remain functional for just a few months. Most instruments can gather data far faster than the communications system can transmit it to Earth due to the limited number of antennas available on Earth to receive the scientific data. Therefore, another key limiting factor on science for a Europa orbiter is the time available to return data to Earth. In contrast, the amount of time during which the instruments can make close-up observations is less important.