Europa Clipper Go For Launch

NASA today cleared the Europa Clipper mission for launch next month. The decision on whether or not to launch has been up in the air for the past several months after the agency learned that transistors on the spacecraft might not be as radiation-hardened as they thought. Tests since then have demonstrated they are fine and the mission will proceed as planned.

NASA Science Mission Directorate head Nicky Fox and JPL Director Laurie Leshin clearly were elated to report the news at a media telecon this afternoon following a final milestone review, Key Decision Point-E.

Clipper “unequivocally” passed the review, Fox exulted, adding that she can’t wait for it to launch next month “and see all the incredible and unprecedented science” it will produce.

The launch window is open from October 10-31. Exactly when it will launch depends on weather and coordinating with other launches taking place from Kennedy Space Center. Europa Clipper will launch on a SpaceX Falcon Heavy from KSC’s Launch Complex 39A.

The largest planetary spacecraft ever built by NASA, Europa Clipper will orbit Jupiter and make almost 50 close flybys of its moon Europa. Scientists believe Europa has a liquid ocean of water under its icy crust. Where there’s water, there may be life.

Curt Niebur, program scientist for Europa Clipper at NASA headquarters, stressed this is not a mission designed to find life, however. Instead, it’s a first step to determine if the conditions for life exist, what NASA calls habitability. If so, a follow-on mission will be needed.

It’s important to note that Europa Clipper is not a life detection mission and there are two reasons for that. One, it would be premature. The first thing we need to do is figure out are the proper ingredients there to support life as we know it. … We’re reasonably confident that almost all of those ingredients are there, but we don’t know for sure. So we need to answer the habitability question first. …

The second reason [is] because we don’t have a life detector. There’s no such thing as a tricorder instrument that we can point at something and it returns a blip or a blop telling us if it’s alive or not. It is extremely difficult to be able to detect life, especially from orbit. So first we’re going to ask the straightforward question — are the proper ingredients there for life to exist? You can bet your bottom dollar that if Europa Clipper tells us yes those ingredients are there that we are going to be knocking on the door fighting for a second mission to go looking for life. — Curt Niebur

With a launch next month, Europa Clipper will arrive at Jupiter in April 2030 after swinging by Mars and then back to Earth to get gravity assists. Over the next four years it will make 80 orbits of Jupiter with 49 swing-bys of Europa, coming as close as 25 kilometers (16 miles) to the surface.

Europa is one of the four Galilean moons of Jupiter first observed by Italian astronomer Galileo Galilei in 1610 and is slightly smaller than Earth’s Moon. The other Galilean moons are Io, Callisto and Ganymede. The European Space Agency’s Jupiter Icy Moons Explorer (JUICE) already on its way to Jupiter will focus its studies on Ganymede, but will also make flybys of Europa. The two space agencies are working together on these missions. JUICE is taking a different route to Jupiter and will arrive after Europa Clipper.

Niebur said he thought he knew from the beginning how difficult it would be to win approval for and build Europa Clipper, but “I was completely and utterly wrong” especially considering what’s happened over the past four months.

Jordan Evans, Europa Clipper program manager at JPL, recounted how an informal conversation at a conference of electronics parts engineers in May created a maelstrom. Someone mentioned to the chief engineer of JPL’s parts organization that a non-NASA customer had data indicating transistors “might fail at something less than they were originally qualified for from a radiation dose standpoint.”

Jupiter is “engulfed in more radiation than any planet in our solar system,” Evans said, and Europa Clipper will fly through the most intense region during its flybys of Europa.

The transistors are basically small electrical switches that turn circuits on and off and are located throughout the spacecraft. They control about 200 unique applications and the impact on the mission if one fails varies depending on the application, Evans explained.

Since May, engineers have been testing the transistors and now are confident they will work just fine in part because they can heal themselves during the portion of each orbit when they are outside the most intense radiation dosage. Europa Clipper will be in a 21-day orbit around Jupiter and will encounter intense radiation only one of those days. The other days the transistors can anneal themselves, a process that is accelerated by heating and NASA will command the circuits to warm up.

Not all of them will need it. “We are only going to anneal a couple of parts right now because the rest of them are fine,” Niebur said.  “Once we get to Jupiter and Europa, if we find that things are degrading worse than we expected, then we can anneal more of them, so we actually have a lot more resiliency to the Europa environment than we originally anticipated.”

Leshin called the last few months a “huge lift — and I think huge lift is a huge understatement” for the Europa Clipper team not only at JPL, but at NASA headquarters, NASA Goddard Space Flight Center, and the Johns Hopkins Applied Physics Lab. “It was an incredible team effort and we’re so grateful for all the support.”

Niebur said he never doubted it would be worth it.

“This is an epic mission. It’s a chance for us to explore not a world that might have been habitable billions of years ago, but a world that might be habitable today.” — Curt Niebur

The Europa Clipper mission owes its existence in large part to former Congressman John Culberson (R-TX) who chaired the House Appropriations Commerce-Justice-Science subcommittee from 2014-2018. A passionate advocate for the mission because he firmly believes there is life in Europa’s ocean, he added money to NASA’s budget year after year to fund the mission even though NASA didn’t request it. He put the language directing NASA to build Europa Clipper in the bill itself, not only in the report, and would proudly say it was the only NASA mission required by law.

He lost his reelection bid in 2018, but the program had progressed far enough by then to continue anyway. Culberson did not prevail on his determination to launch Europa Clipper on the Space Launch System or for NASA to build a lander as well as an orbiter. SLS basically was too expensive (the Office of Management and Budget said it would cost $2 billion compared to $0.5 billion for a commercial rocket like Falcon Heavy) and many viewed a lander as premature since so little is known about Europa’s surface.

NASA’s science priorities are guided by Decadal Surveys conducted every 10 years (a decade) by the National Academies of Sciences, Engineering, and Medicine. The 2011 planetary science Decadal Survey did not recommend a Europa mission as the top priority, however, because of its cost, then estimated at $4.7 billion. JPL redesigned the mission to orbit Jupiter and swing-by Europa instead of orbiting Europa itself, lowering the cost to an estimated $2 billion, but it has grown significantly since.

In 2019, then-SMD head Thomas Zurbuchen cancelled one of the instruments and replaced it with a less expensive alternative, but costs kept rising to $5 billion. Fox said today the life cycle cost now is “just under $5.2 billion.”