And we're off! Watching the Falcon Heavy launcher effortlessly lift the 6-ton Europa Clipper spacecraft into the sky on the 14th of October was a remarkable sight. The second flagship mission focused on exploring an Ocean World has now begun its journey. In six years, we'll have another remarkable sight: high-resolution images of one of the most important planetary objects in our Solar System: Jupiter's moon Europa.
When I started writing my book on the Ocean Worlds seven years ago, both ESA's Juice mission and NASA's Europa Clipper were still in their development stages. The Europa Clipper was even in a precarious situation as it was in the crossfire of the U.S. Congress due to ballooning costs, and to make matters worse, it was initially planned to be launched on the now-flagging SLS launcher. Given the scale, complexity, and costs of such missions, it was anyone's guess whether they would be completed on time or even funded until the end. And yet, after Juice's successful launch earlier last year, it is Europa Clipper's turn now to be on its way towards the Jovian system (with the help of a few gravity assists along the way). We live in extraordinary times.
What is truly remarkable though is that both missions are going to be in the Jovian system at roughly the same time. To understand how fortunate this is, we have to go back to the origins of each mission. Back in 2008, both NASA and ESA envisaged a grand project where a two-spacecraft mission would investigate Jupiter and the Galilean moons at the same time: the two 'rocky' moons, Io and Europa, would be covered by NASA's Jupiter Europa Orbiter (JEO), while the tow 'icy' moons, Callisto and Ganymede, would be covered by ESA's Jupiter Ganymede Orbiter (JGO). Having two spacecraft working in tandem around Jupiter and its satellite system would significantly expand and enrich the scientific output as different instruments could be used to study the same targets, sometimes at the same time, allowing data to be cross-checked and their interpretation refined. This was one of a primary factors behind this dual assignment.However, with the U.S. Congress realizing that JEO's costs would be significantly more than what had been initially estimated, the mission was canned. Europe on the other hand decided to carry on with the JGO mission and Juice (Jupiter Icy Explorer) was born.
In the meantime, NASA was asked to come up with an alternative to JEO, one with more manageable costs. The new mission that was proposed was an ingenious one; the spacecraft would perform elongated orbits around Jupiter, allowing it to do over 40 close flybys of Europa without spending much time in radiation-intense zones, therefore reducing the need for protection and spacecraft weight. And thus, the Europa Clipper was born. Yet, it was now operating as a single mission, completely independent from Juice's launch schedule. Due to a fortunate turn of events though, both missions will now share some time together in the Jovian system!
Another great news is the fact that Europa, arguably one of the most important planetary objects in our solar system, has one the least well imaged surfaces. The resolution of the images we have of Europa are very poor (the majority of images have a resolution of 1 to 4 km per pixel) and the characterization of the surface compounds incomplete. This is due to the technical difficulties encountered by the Galileo spacecraft which flew by the moon repeatedly over twenty years ago; the sole mission to do so. We desperately need higher resolution images and full characterization of the surface to better understand the subsurface ocean hidden under the moon's thick ice shell. What are the orange stipes crisscrossing the surface really made of? How deep is the ice shell? Are there geysers spewing water out into space? These questions and many more will be addressed by the Europa Clipper and its suit of 9 scientific instruments.
Ultimately, what we'd really like to know is if the subsurface ocean is habitable as we think it is, and if so, might it harbor lifeforms—most likely microbial. Such questions, the Europa Clipper will not be able to answer conclusively, but it is the first positive step towards answering such questions. The next stage will be to send a lander to study in situ the material on the surface, followed by a sample return mission. These missions will most likely take place in the second half of the twenty-first century so don't hold your breath.
With the Europa Clipper, a new exciting frontier is about to be explored and we are lucky enough to be there to witness it! As always, onwards and upwards.
Image: SpaceX and NASA
Comments