Mars Rovers Let Us Experience Another World Through Robot Eyes
Mars in True Color
Our Future Home?
Mars is the only planet where we can land and (perhaps) survive. There's solid ground, a true sky, weather and water frozen in the ground.
For over a decade, our robotic rovers have been exploring the red planet and making remarkable discoveries. They've survived planetary dust storms, punishing Martian winters lasting twice as long as ours, dangerous solar flares with no magnetic field and precious little atmosphere to protect them, and temperature swings from about 90° F to -150° F. Someday, humans will brave these hazards, on a planet that is nine months away from Earth during closest approach, and at times more than a year away.
Mars looks surprisingly familiar, like the bleaker parts of Utah or Africa. Yet images are deceptive.
Pause a moment to contemplate this alien world which our inheritors may one day call home.
[Note: this page showcases fabulous photos of Mars from rovers and orbiters prior to Curiosity. My liveblog of the Mars Curiosity landing is on a separate page.]
- Size: 4 222 miles (6794 km) in diameter, about half that of Earth
- Land area equal to that of Earth, since it lacks oceans
- Atmosphere: mostly carbon dioxide; almost no oxygen
- Length of Martian year: 687 Earth days
- Length of Martian day: 24.6597 Earth hours
- Temperature: Highest temperature at the equator about 86° F, but usually well below freezing. (See this chart of Mars temperatures measured by different Martian landers)
- Why is it red? Its rocks contain a lot of iron, and it's rusted!
- Signs of liquid water temporarily flowing on the surface discovered June 2012.
Photo Gallery of Martian LandscapesClick thumbnail to view full-size
Below is a video overview of our 2004 robotic rover missions: Spirit and Opportunity. There's a lot of great panoramas and photos of some of the sites they've visited.
The missions were only supposed to last three months, but NASA and JPL have been able to push them many years and many miles farther than they were designed for. It can take up to twenty minutes for a radio signal to travel one way to Mars, depending on its position relative to Earth, and there's no way to help the rovers if they get stuck, so Mission Control drives them very, very cautiously, pausing often to snap photos or take samples.
Five Years on Mars: 2004-2009
Spirit finally conked out in 2010, when a long winter and dust on the panels sapped it of energy. As of summer 2012, Opportunity is still going strong, although it's parked right now to try to survive yet another long winter with its panels angled towards the sun as much as possible. It could use one of Mars' frequent dust devils to give it a spring cleaning.
Joking aside, Martian dust will be a real problem for future expeditions, as it tends to gum up electronics and kill solar panels. Dust devils are fine, but sometimes Mars can be enveloped in planetary dust storms that completely shroud the surface.
Dust Devil Photographed by Spirit Rover
Sunset on Mars from Opportunity Rover
Sun Partially Eclipsed by Martian Moon Phobos
The Red Planet: A Frozen Desert
We don't realize how good we have it on Earth: magnetic fields to block most solar flares, a thick atmosphere that blocks harmful radiation and allows liquid water to collect on the surface, mountains and land to slow down storm winds, and a big moon to stabilize the planet's tilt and climate.
Mars had all of these except the big Moon, but lost them long ago. Its patchy remnants of magnetic fields are not strong enough to block the Sun's radiation. Over billions of years, the solar wind has stripped away most of its atmosphere, leaving only a thin atmosphere of carbon dioxide. Air pressure and temperature dropped so much that any oceans would have dried up, the lakes and rivers vanished, and water froze in permafrost or in polar ice caps.
Our current generation of Mars rovers have found tantalizing hints of the planet's watery past. Yet Mars is not quite a dead world: great dust storms and dust devils tear across the planetary deserts, and our Phoenix lander on the north pole has seen snow.
We've also gotten to watch Martian sunsets. Oddly, the iron oxide dust in the air gives the sun a faint bluish tint near the horizon (see this photo gallery).
Santa Maria Crater, December 2010
Why Go to Mars?
Mars doesn't seem very inviting, does it? It's a nine month journey to get there, and we have yet to find a way to counteract the bone and muscle loss suffered by astronauts who spend months in zero G. Also, astronauts will be vulnerable to the deadly radiation of solar flares without proper shielding.
So why go?
Because we need to become a two-planet species. Sooner or later, Earth could be struck again by a large asteroid like those that have caused planetary catastrophes in the past. Our planet's resources are not inexhaustible, and 7 billion people are already beginning to strain its capacity. Even if we overcome all these problems, the Sun is gradually brightening as it enters middle age, and will eventually cook our skies and seas. Mars will be the future ark of humankind.
Mars doesn't look very hospitable now, but if we use the greenhouse effect to bulk up its atmosphere, we might be able to turn it into a water world once more. Someday, we may be able to make the mythical canals of Mars a reality.
We have time, but not forever. Our descendants need us to consider their future, not just ours.
That's why we're exploring Mars with robots, right now.
Because we don't want to send any humans until we've worked out all the kinks. Sending golf-cart-sized robots was hard enough. Next up, a 1-ton all-terrain vehicle, Mars Curiosity, that can do much, much more. Assuming it survives the crazy landing required for something that heavy:
Seven Minutes of Terror: Curiosity Reaches Mars on Aug. 5, 2012
Virtual Rover App
Mars Curiosity Has Landed!
As I noted above, I liveblogged the Curiosity rover's landing on a separate page, where I've got photos and videos from descent and landing and waking-up.
Once she gets rolling, I'll start collecting her best photos on a new page. Below is a teaser: her first clear view of the base of the mountain she's going to climb.
Also, speaking of Curiosity, check out the video at right demonstrating a free iPad app that lets you project a virtual model of the Curiosity Rover on your desk (or cat)!
Photo from Mars Curiosity Rover: Mt. Sharp, Taken August 8, 2012
Earth and Mars: The Blue and Red Planets
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