Kamikaze Cassini ends historic trip
When you read this, NASA’s Cassini spacecraft will have crashed into the giant ringed world Saturn, where spring lasts for seven years.
It’s a planned kamikaze drop to avoid the spacecraft one day colliding with any of Saturn’s 60-plus moons that may contain basic life.
When the Cassini spacecraft hurtles at 111,000km/h through Saturn’s mysterious rings and into the planet’s hydrogen and ice atmosphere, NASA mission control will be ready to record history.
They’ll be relying on the deep space antenna in Canberra to handle the historic finale to a 7.8 billion-km voyage. CSIRO’s team at the Canberra Deep Space Communication Complex will capture the final nine hours of signals from Cassini until it plunges into Saturn, 20 years after its launch from Cape Canaveral.
The Cassini spacecraft spent 13 years orbiting Saturn. It revealed the planet and its rings in striking detail, found liquid around every corner, and invigorated the idea alien life not only exists, but could be right on our doorstep.
Launched on October 15, 1997, Cassini travelled for six years before reaching Saturn.
The sixth planet lies an average of 1.5 billion kilometres from Earth. Cassini took the scenic route, orbiting the Sun to fly by Venus twice, then Earth, then to a gravity-assist manoeuvre at Jupiter before reaching its destination.
They call it the “sling-shot effect”.
The craft has been orbiting the ringed planet since July 1, 2004, studying Saturn’s fascinating moons, tiny ring particles, and turbulent atmospheric storms, including a massive hexagonal swirling storm at the north pole that could swallow the Earth whole. The data signals take more than 80 minutes to reach earth at the speed of light.
Cassini is the most distant planetary orbiter ever launched and will be completely ripped apart as it plunges through Saturn’s thick clouds. The gravity will crush it and the friction will melt what’s left. If it transmits data for just a few minutes we’ll be doing well.
September is a historic month for other reasons.
It’s 40 years since Voyagers 1 and 2 were launched to study the outer Solar System. They were launched in 1977 to take advantage of a favourable alignment of Jupiter, Saturn, Uranus, and Neptune, and are now exploring the outer boundary of the “heliosphere” where the Sun’s energy basically finishes.
Both probes continue to collect and relay useful scientific data. On August 25, 2012, data from Voyager 1 indicated it had become the first human-made object to enter true interstellar space.
Voyager 1 is moving with a velocity of 17km/sec. and could reach another star system within 80,000 years.
Another historic moment was reached on August 21 as more than one billion people, directly and online, watched what was billed as the Great American Eclipse. It was the first time in 99 years a solar eclipse crossed the US and lived up to its reputation as the most watched sky event in history.
NASA’s Cassini spacecraft, which has been in orbit around Saturn since 2004, has come to the end of its mission.