Our ongoing efforts to explore the Solar System...and beyond
Late last week, one of humanity’s most valiant emissaries, the Cassini Probe, met its end in the crushing atmosphere of Saturn. Cassini scientists dove the bus-sized robot into Saturn’s atmosphere on Friday, ending it’s almost 20-year mission in a literal blaze of glory.
Why they did this is fairly simple; after 20 years, Cassini was basically out of maneuvering fuel. (It’s on-board nuclear plant was good to go for a while, but that was just to keep things warm and to power experiments. It couldn’t steer anymore.)
So, to prevent Cassini from possibly crashing into, and contaminating, a Saturnian moon, they dove it into Saturn itself where no known hitch-hiking Earth microbes could possibly survive.
With its demise, Cassini joins the list of great probes that we have sent out into the Solar System. So, this month, I’d like to look back at some of those probes, and what they gave us.
Pioneer 10 and 11
Launched in 1972 and 1973, these twin probes became the first to encounter Jupiter and Saturn, respectively. Sending back a wealth of data and absolutely dazzling images, they were the first to explore the space beyond Mars and the Asteroid belt.
Both Pioneer craft have golden plaques attached to them showing what humans look like and how to find our solar system. (This is seen by some as a “Come and eat us!” invitation, but, honestly, you’d have to be really hungry to come all this way for a meal.)
Communication with both probes was lost more than a decade ago and both probes will eventually leave the solar system and enter Interstellar space.
Voyager 1 and 2
Launched in 1997, Voyager 1 and 2 were sent on what was called a “Grand Tour” of the Solar System. Voyager 1 visited Jupiter and Saturn, while Voyager 2 took a more leisurely path that allowed it to visit Jupiter, Saturn, Uranus and Neptune.
Among the more interesting discoveries of the Voyager probes were the volcanoes on Jupiter’s moon, Io, the “spokes” in Saturn’s rings, and the fact that Jupiter, Uranus and Neptune have ring systems themselves.
Both Voyager probes have video discs attached to them, along with the hardware and instructions necessary to build a play back device. These discs contain greetings from Earth in both audio and video formats. (The full content of these discs are available on the internet and are worth looking up if you are curious.)
The Voyagers are also on courses out of the Solar System. Voyager 1 actually left the Solar System a few years ago and is now the furthest man-made object in existence.
Galileo
Launched in 1989, the Galileo’s primary mission was to study Jupiter and follow up on the findings of earlier probes. Along the way, it encountered asteroids (finding the first asteroid with a moon of its own!), made observations of our moon and, using a set of criteria devised by Carl Sagan, detected life on Earth! (Making it the first example of the detection of life from space.)
Once at Jupiter, the hits kept coming. First, it deposited a probe into Jupiter’s upper atmosphere to study that strange environment. It also found that Io is insanely volcanic, with about 100 times the volcanic activity we have here. And, it found lots of evidence that Jupiter’s moon Europa has a subsurface water ocean, which might contain at least microbial life.
The Galileo mission ended similarly to the Cassini mission, with team scientists sending the probe into Jupiter itself, so that it couldn’t accidentally contaminate Europa or any of the other Jovian moons.
New Horizons
Finally, we have the New Horizons probe, which flew past Pluto in July of 2015. This was the first time Pluto had ever been visited, and, to get there in a timely fashion, the probe was sent streaking past Pluto at a speed that kept it from going into orbit. But, even at this high speed (38,000 mph), it still managed to send back breathtaking images of a truly alien world unlike any we’d seen before.
And now, New Horizons is set to encounter another object unlike any other. In January 2019, the New Horizons probe will fly by an object so remote that it doesn’t even have a proper name yet: “(486958) 2014 MU69”. So, here’s to the great probes like Cassini and the dedicated teams that keep them flying. Thank you all for expanding our knowledge of, and out into, the universe.
Steven W. Disbrow is a programmer who specializes in e-commerce and mobile systems development, an entrepreneur, comic-book nerd, writer, improviser, actor, sometime television personality and parent of two human children.