550 miles. Just 884 kilometers. That's the distance that separates, as you read these lines, Europa Clipper from the surface of Mars. A “hair” in astronomical terms. A flyby as close as it is crucial, a maneuver calculated to the millimeter to bend the trajectory of the largest probe ever built by NASA.
This space giant, as wide as a basketball court when it unfurls its massive solar panels, is using the red planet as a cushion in an elaborate game of cosmic billiards. The ultimate target? The moon Europa, the icy world that orbits Jupiter and hides an ocean beneath its frozen crust that could (and the conditional is a must) host life forms. It's a $5,2 billion mission, a colossal investment to answer the classic question: are we alone in the universe?
Europa Clipper, a Billiards Stand Through the Solar System
Europa Clipper's gravitational dance around Mars is no accident. As stated Ben Bradley, mission planner at NASA's Jet Propulsion Laboratory:
It's like a game of billiards through the solar system, flying past a couple of planets at just the right angle and time to gather the energy needed to reach Jupiter and Europa. Everything has to line up: the geometry of the solar system has to be perfect for that.
Probe It will reach its closest point to Mars at 18:57 Italian time., traveling at speeds that would put any Earth supercar to shame: about 24,5 kilometers per second. Before and after this crucial moment, the spacecraft will use Martian gravity to alter its trajectory, slowing to 22,5 kilometers per second as it moves away from the red planet.
Scientific tests during the flyby
This close passage does not only serve to change the course. The NASA It's also using it as an opportunity to test two of the science instruments on board. Engineers will turn on the spacecraft's thermal imager to capture multicolored images of Mars, putting the sophisticated device to the test.
Europa Clipper's radar instrument will also be tested during the approach. The spacecraft's radar antennas are so massive that they have not been fully tested on Earth, making this the first time all of its components have been tested together.
The long journey to Europe
Today's maneuver is just one stage of a much longer journey. As explained Brett Smith, mission systems engineer at the Jet Propulsion Laboratory:
We arrive very quickly, and the gravity of Mars acts on the probe to bend its path. In the meantime, we exchange a small amount of energy with the planet, so that we set off on a path that will bring us back close to Earth.
That flyby around Earth is scheduled for December 2026, and will position the probe for a direct trajectory towards its final destination. The arrival in the Jupiter system is instead scheduled for April 2030, when this ambitious mission finally begins its scientific work around the icy moon Europa. We're in for some great stuff!
