SOLAR SYSTEM

When You Go to Mars

by Diane Boudreau

Who will be the first person to set foot on Mars? It could be you! The National Aeronautics and Space Administration (NASA) hopes to send people to the Red Planet sometime in the next 20 years.

Sending a person to Mars will be much more difficult than sending a person to the moon. Our moon is only 238,900 miles away. Mars, on the other hand, is about 35 million miles away when at its closest orbit to the Earth, and about 248 million miles away at its farthest orbit. Naturally, NASA will plan to launch missions to Mars when the planet is at its closest point to the Earth.

Even so, it will still take 11 months to reach Mars. Once you get there, you will have to stay on Mars for an entire Earth year. You must wait for the two planets to again be in the right position before beginning the long trip home. The entire round-trip journey will take almost three years. You will need to take enough food, water, and fuel to survive that long in space.

You will not be bored. There will be plenty of work to do during the trip. One of the most important jobs is to maintain equipment so that the spacecraft operates safely. You might also take photographs, conduct experiments, keep a logbook of the journey, or guide the spacecraft. In addition, there are the usual daily chores such as preparing meals and cleaning up.

When you finally get to Mars, the spacecraft will use rockets to slow down. Then you will go into orbit around the planet. You and your crew will ride in a lander to reach the planet's surface. The main spacecraft remains in orbit.

You must wear a spacesuit when you leave the lander. The suit provides air to breathe, because the atmosphere on Mars is very different from the atmosphere on Earth. On Earth, air contains 21 percent oxygen, .035 percent carbon dioxide, and 78 percent nitrogen. The air on Mars is made of mostly carbon dioxide (95 percent). Only .1 percent is oxygen-not nearly enough oxygen to keep you alive!

The spacesuit will also keep you warm. At the Martian equator, the surface temperature changes from 21 degrees Celsius (70 degrees Fahrenheit) at your feet to zero degrees Celsius (32 degrees Fahrenheit) at the top of your head. Left exposed to the Martian climate, you'd have to wear sandals and a ski hat! Fortunately, your spacesuit will keep you at one comfortable temperature from head to toe.

The suit will also regulate pressure. Air pressure on Mars is only .8 percent of that found at sea level on Earth. Without a pressurized space suit, your internal organs would push out against your skin and make you look like a big marshmallow.

Gravity on Mars is only 38 percent of Earth's gravity. That means if you weighed 100 pounds on Earth, you would only weigh 38 pounds on Mars. You could jump three times as high on Mars as you can on Earth. If you had a basketball hoop there, you could make some spectacular slam-dunks!

You won't have much time for games, however. You and your crewmates will be too busy exploring a strange new environment. Mars is reddish-colored, because of all the iron oxides found in the rocks. The ground is dry and dusty. There are plenty of rocks of all shapes and sizes. As far as we know to date, there is no liquid water.

The sky might look pink or light brown because of all the red dust scattered by the wind. You might even see a spectacular Martian dust storm that lasts for months. Looking beyond the dusty atmosphere, you'll see two tiny potato-shaped moons, Deimos and Phobos.

Mars is home to the biggest volcano and the longest, deepest canyon in the solar system. The Olympus Mons volcano is 27 kilometers high, three times as tall as Mt. Everest on Earth. The Valles Marineris canyon is seven kilometers deep and 4,000 kilometers long. That's nearly four times as deep as the Grand Canyon and longer than the entire United States!

Measuring time on Mars will also require different calculations. One Mars day (the time it takes for the planet to spin around its axis) lasts 24 hours and 37 minutes, very close to the 24 hours in one Earth day. But one Mars year (the time it takes Mars to go around the sun) takes 686.7 Earth days or 1.88 Earth years.

You won't experience a full Martian year because you'll have to return to Earth before it's complete. However, because you will have used up half of your fuel and food, you'll have some room on your spacecraft to bring home interesting rock samples. Back on Earth, scientists will want to study these rocks in detail.

Who knows? Maybe you'll even bring back the fossil remains of a million-year-old Martian microbe!