While the word probe is used conversationally to mean to examine physically or refers to an instrument designed for that sort of physical examination, the word probe comes from a Latin word meaning to test or the result of such a test, proof. Today, we celebrate both senses of this word and the spacecraft that embody both meanings, that carry out our examination and testing of the universe that surrounds us.
On this date in 1978, NASA launched a satellite called Landsat 3, part of the ongoing Landsat program. Rather than studying the far reaches of space, Landsat is designed to study Earth, to give us a comprehensive view of our own planet. Technically, because Landsat orbits Earth, maybe it’s not a space probe, but the dates align, and the mission echoes the term’s underlying meaning. And NASA doesn’t make that distinction by location in the universe; it calls Sputnik 1 the first space probe and defines a space probe as an unmanned spacecraft designed for scientific research.
The Landsat 3 spacecraft gave a thorrough study of Earth—a variety of images covering the planet’s entire surface—in 18 days. It was designed to orbit and send back data for about a year; more than five years after launch, Landsat 3 was finally decommissioned.
Landsat 8 launched just over a year ago, and we wrote about the amazing program then. Landsat satellites continue to provide data about the Earth’s surface to scientists and many others. The information from Landsat helps aircraft avoid bird strikes and helps wine growers and farmers manage their crops for maximum yield and deliciousness. Landsat 7 allowed scientists to count and track penguins in the Antarctic. The images and data from Landsat are available to anyone who wants to use it.
On this date in 1979, Voyager 1 made its closest pass of Jupiter, sending back information about the planet’s climate, surface, and moons. The Voyager 1 and Voyager 2 spacecraft were launched in 1977 and continue to travel farther and farther from Earth. In fact, Voyager 1 left our Solar System and entered interstellar space in 2012, with Voyager 2 set to follow its twin in a few years.
Not only is Voyager 1 giving us information from the farther than any manmade object has ever travelled, but it is also carrying information from Earth. We wrote about this Golden Record in an article called “Voices Carry” for The Huffington Post, as part of their TED Weekends series. There, we explained:
In 1977, NASA, with a committee headed by astrophysicist Carl Sagan, designed two phonograph records, then put each aboard a Voyager spacecraft. The record contains greetings in 56 languages, natural sounds like thunder and crickets chirping, and music from around the world, all of which are in audio. The disc also includes, in analog form, 115 images, from planets to fetuses.
Perhaps the most interesting information to be included in our official, communal voice is an hour-long recording of the brainwaves and heartbeats of Ann Druyan. Hooked up to machines, she was given a list of things to ponder, starting with the history of the Earth. This woman went on to marry Sagan, with whom she would work on the television series Cosmos. When we saw Druyan at PlanetFest in 2012, she described her contribution to the Golden Record as the heartbeat of a young woman in love.
On this date in 1982, the Soviet spacecraft Venera 14 landed on Venus. The identical Venera 13 and Venera 14 spacecraft—each flying a combination mission that included flyby-and-landers—launched five days apart and landed within six-hundred miles of each other. The temperature was well about 800ºF. After travelling for three months to get to the planet between Earth and Mercury, each probe was designed to take photographs and perform soil tests for 32 minutes; Venera 14 held up for almost an hour, and its twin lasted more than two hours. Venera 13 sent back to Earth the first color images of Venus.
Landsat 8 continues to orbit Earth, and the two Voyagers continue to travel ever farther from Earth. Less than a month ago, NASA began an adjustment of the orbit of Odyssey around Mars, in hopes of getting a better look at that planet’s morning fog by the end of next year. In January, Rosetta, the European Space Agency’s comet-chasing spacecraft, started sending back signals to Earth, after a planned 31-month nap. A host of space probes are out there doing what space probes do. Today, we take a few minutes to ponder what that might mean about who we are and how we know our universe.