Published : Friday, September 15, 2017 | 5:32 AM
The spacecraft’s grand finale, its death plunge into Saturn’s atmosphere, occurred according to NASA’s carefully plotted plan at 3:31 a.m. Communication was lost about one minute later.
At Caltech, hundreds gathered to monitor information about the spacecraft’s demise on viewing screens in a courtyard. Many in the crowd, engineers and scientists, had worked for twenty years on the Cassini mission. The bittersweet final, quiet minutes evoked different spontaneous reactions: thoughtful silence, clapping, a few cheers.
At JPL, project team members hugged each other and delivered a standing ovation.
Cassini ended its 13-year tour of the Saturn system with an intentional plunge into the planet to ensure Saturn’s moons — in particular Enceladus, with its subsurface ocean and signs of hydrothermal activity — remain pristine for future exploration.
During its dive into the atmosphere, the spacecraft’s speed was expected to reach approximately 70,000 miles per hour. The final plunge took place on the day side of Saturn, near local noon, with the spacecraft entering the atmosphere around 10 degrees north latitude.
At approximately 930 miles above Saturn’s cloud tops, Cassini began to burn up like a meteor. Within about 30 seconds following loss of signal to Earth, the spacecraft began to come apart; within a couple of minutes, all remnants of the spacecraft were completely consumed in the atmosphere of Saturn.
Even as Cassini’s fate was sealed, the spacecraft continued to make groundbreaking scientific observations of Saturn up until the last moment it was functional.
All of the mission’s magnetosphere and plasma science instruments, plus the spacecraft’s radio science system, and its infrared and ultraviolet spectrometers collected data during the final plunge.
Earlier in the week, JPL’s Cassini project manager Earl Maize said that Cassini’s final signal “will be like an echo.”
“It will radiate across the solar system for nearly an hour and a half after Cassini itself has gone,” said Maize. “Even though we’ll know that, at Saturn, Cassini has already met its fate, its mission isn’t truly over for us on Earth as long as we’re still receiving its signal.”
Cassini’s last transmissions were received by antennas at NASA’s Deep Space Network complex in Canberra, Australia.