Photo by: NASA

NASA

The 5 Greatest Robotic Space Explorers

Our little silicon friends have been exploring the harshest environments in the universe - space itself - in humanity’s name for decades. And while tales of their robotic exploits could fill an entire book, let’s count down the top five.

February 25, 2021

5. New Horizons

The location of the New Horizons Ralph instrument, which detected methane on Pluto, is shown. The inset is a false color image of Pluto and Charon in infrared light; pink indicates methane on Pluto’s surface.

Photo by: NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute

NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute

The location of the New Horizons Ralph instrument, which detected methane on Pluto, is shown. The inset is a false color image of Pluto and Charon in infrared light; pink indicates methane on Pluto’s surface.

Launched in 2006, New Horizons spent nine and half years in silent reverie as it cruised the outer depths of the solar system, sailing past all four of the giant planets at a speed of 36,000 mph. Finally, in the summer of 2015, it reached its target: Pluto. First discovered in 1930, the little planet-not-a-planet remained as nothing more than a speck of light for decades. Even the powerful Hubble telescope could only reveal a blurry, fuzzy patch of questions. But in the 15 minutes that New Horizons spent taking the portrait of that distant world (you don’t exactly slow down a spacecraft like that), humanity discovered that little Pluto featured giant mountains made of ice, glaciers made frozen nitrogen, and more mysteries for later missions to uncover.

4. Cassini-Huygens

Illustration of NASA’s Cassini spacecraft during its final plunge into Saturn’s atmosphere on Sept. 15, 2017.

Photo by: NASA/JPL-Caltech

NASA/JPL-Caltech

Illustration of NASA’s Cassini spacecraft during its final plunge into Saturn’s atmosphere on Sept. 15, 2017.

13 years. 13 years. That’s how long NASA’s Cassini spacecraft spent in orbit around the giant ringed world of Saturn. In that time spent in its lonely orbit, astronomers discovered new moons, found just how intricate the rings are, watched in awe and wonder as the planet changed color, and more. A companion lander, the Huygens probe, descended onto the shrouded moon of Titan, a mysterious world with seas of liquid methane and a thick atmosphere nitrogen. When it comes to a combination of longevity and discovery in the interplanetary depths, its hard to beat Cassini.

3. Venera

Venera 13 was launched on 30 October 1981 and Venera 14 was launched on 4 November 1981. They journeyed to Venus and deposited their landers on 1 March and 5 March 1982, respectively. There were 2 high-energy instruments aboard each spacecraft, one a continuation of the French-Soviet collaboration and one called the "Konus" experiment. These experiments returned data until March 1983.

Photo by: NASA

NASA

Venera 13 was launched on 30 October 1981 and Venera 14 was launched on 4 November 1981. They journeyed to Venus and deposited their landers on 1 March and 5 March 1982, respectively. There were 2 high-energy instruments aboard each spacecraft, one a continuation of the French-Soviet collaboration and one called the "Konus" experiment. These experiments returned data until March 1983.

For over 20 years, the Soviet Union doggedly launched mission after mission to Venus, Earth’s twin sister world. Most of them failed, but it wasn’t the fault of the Soviets. Venus is hands-down one of the nastiest planets in the solar system, which surface pressures over 90 times that of the Earth’s, and temperatures hot enough to melt lead. Of all the Venera missions, ten managed to make it to the surface, giving the Soviets space agency a raft of notable firsts: the first human-made device to enter the atmosphere of another world, the first to make a soft landing on another planet, and the first to return pictures from the surface of another planet. None of the landers managed to last in that hellish environment for more than a couple hours, but without them we would have no idea of the true surface of Venus.

2. Sojourner

Lander image of rover near "The Dice" (three small rocks behind the rover) and "Yogi" on sol 22. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements.

Photo by: NASA/JPL

NASA/JPL

Lander image of rover near "The Dice" (three small rocks behind the rover) and "Yogi" on sol 22. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements.

NASA’s Sojourner, “the little rover that could”, ignited imaginations around the world when it began its tour of Mars in 1997. Just two feet long and weighing 25 pounds, the solar-powered robot was the first wheeled vehicle to traverse another planet. While it only lasted 85 days, the mission proved worthy of its name – Pathfinder – as it proved the technology necessary to send larger, more capable rovers to the Martian surface. These missions are in operation today (with more on the way!) hunting for signs of past life and scoping out possible landing sites for a future human visit.

1. The Voyagers

Photo by: NASA/JPL

NASA/JPL

Of course the #1 spot has to go to the Voyagers. Launched in 1977, the twin spacecraft took advantage of a rare alignment of the outer planets to give humanity its first “grand tour” – a serious of close-up pictures of Jupiter, Saturn, Uranus, Neptune, and their moons. Never before had we seen those worlds to that level of detail. And in the case of Uranus and Neptune, The Voyager missions remain our only portrait of them. Both spacecraft are still operational, with Voyager 1 becoming the first human-made object to breach interstellar space in 2012. They are humanity’s ultimate emissary, an artefact of our civilization that will continue to travel the Milky Way galaxy for hundreds of millions of years to come. Even if we never launch another space probe, at least we had the Voyagers.

Paul M. Sutter

Paul M. Sutter is an astrophysicist at Stony Brook University and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of How to Die in Space.

Next Up

This All-Civilian Space Mission Wants to Achieve the Highest Human Orbit Ever

Last year marked a fascinating turning point in the history of spaceflight. For the first time ever, more civilians went into space than professional ones. The private companies Virgin Galactic, Blue Origins, and SpaceX all offer seats for sale, with missions as brief as just a few minutes to as long as a few days.

NASA Has a New Supersonic Jet and It’s Super-Quiet

There’s more to NASA than space. The agency’s full acronym stands for National Aeronautics and Space Administration. I’ve covered plenty of interesting stories in the space sector, so it’s time to the aeronautics side some love too.

Check Out NASA’s DART Mission

It’s like “Armageddon” but in real life.

William Shatner Becomes Oldest Man to Travel to Space After Successful Blue Origin Space Flight

On the morning of October 13, William Shatner joined the crew of New Shepard for its second crewed flight, NS-18. Due to a few holds, the scheduled 10A liftoff was delayed by about 50 minutes from Blue Origin's Launch Site One in Texas. Despite the delays, liftoff and touchdown went off without a hitch, making Star Trek star William Shatner the oldest man to go to space.

What You Need to Know About Blue Origin’s Launch into Space with Billionaire Jeff Bezos

The countdown has begun for Blue Origin’s first crewed spaceflight. On Tuesday, July 20, 2021, at 9:00A ET, Jeff Bezos and three crewmates are lifting off into space from Blue Origin’s Launch Site near Van Horn, Texas. Watch SPACE LAUNCH LIVE: BLUE ORIGIN & JEFF BEZOS GO TO SPACE on Discovery and Science Channels at 8:00A ET or at washingtonpost.com.

Countdown to Launch: NASA and SpaceX Crew-2 Mission

Liftoff set for Friday, April 23, at 5:49A EDT marks the second operational flight of SpaceX’s Crew Dragon. Four space explorers are heading to the International Space Station for a six-month stay. It will take them 23 hours to reach their destination.

Richard Branson of Virgin Galactic Successfully Travels to Space

On Sunday, July 11, around 11:30A ET, Richard Branson, the founder of Virgin Galactic, soared to the edge of space as a passenger aboard Virgin Galactic’s VSS Unity. The space plane then landed safely at Spaceport America in New Mexico, making Branson's space tourism dream come true.

Liftoff of NASA and SpaceX Crew-2!

The NASA and SpaceX Crew-2 mission launched on Friday, April 23 at 5:49A ET from the NASA Launch Complex 39A. This historic milestone marks the second operational mission of SpaceX’s Crew Dragon. Onboard was NASA astronaut Shane Kimbrough, NASA astronaut Megan McArthur, ESA astronaut Thomas Pesquet, and JAXA astronaut Akihiko Hoshide. After a 23-hour journey, Crew-2 successfully docked with the International Space Station (ISS) on April 24 at 5:08A ET. Here's everything that happened from launch day to the Crew-2's arrival at the ISS. (Updated April 24, 2021)

NASA's New Rocket is Taller than the Statue of Liberty

The massive space launch system was unveiled last week. Following successful completion of upcoming simulation tests, NASA will set a date for the first of the Artemis II lunar missions.

25 Years In the Making, the James Webb Telescope Is Coming to Science Channel

The world’s most powerful observatory - the James Webb Space Telescope – is set for launch later this month after more than 25 years of development and construction. Science Channel, the leader of all things space, will take viewers inside this incredible feat of technology and its launch with two specials airing Tuesday, December 21 at 10 PM ET/PT with a Post-Launch Special to air Sunday, December 26 at 10 PM ET/PT.

Related To: