Washington: On Friday, NASA watched its 20-year-old, $4 billion-plus spacecraft crash into Saturn.
The space agency had no other choice. Cassini was nearly out of fuel and had already been stretched years beyond its intended mission duration. Keeping it going risked potentially contaminating one of Saturn’s moons — like Enceladus, an ice world that has some ingredients for life, or Titan, a dynamic moon where it rains methane — with microbes from Earth.
And so the spacecraft ended its existence by literally going where no human-made object has gone before: into Saturn’s atmosphere.
But up through its very last moments, Cassini was conducting a scientific investigation. As it descended into Saturn’s atmosphere, several of its instruments were turned on, including the mass spectrometer, which could essentially “sniff” the atmosphere and determine the chemical compounds therein. That data was beamed back in real time, and will be analyzed in the coming weeks and months.
Cassini has made discoveries that have changed our understanding of Saturn and the cosmos at large. The spacecraft discovered whole new moons around Saturn, lakes of methane on Titan, jets of water erupting from Enceladus. It expanded our understanding where life could possibly exist in our solar system and in the broader universe.
But the ending is bittersweet: Scientists dedicated decades of work to the mission and the study of Saturn, and Cassini ends its run with some key Saturn mysteries still unsolved.