Q) How will the rovers get back to Earth?
A. Spirit and Opportunity will not return to Earth. All of the data that the rovers collect are sent back to Earth via radio waves, so there is no need to bring the rovers back to Earth once they have completed their missions.

Q) Is the rover controlled by itself or controlled by scientists on Earth?
A. Scientists and engineers can't see the rover in real time. There is no joystick. Communication with Earth is only twice per sol (martian day) so the rover is on its own (autonomous) for much of its journey across the martian landscape. Scientists send commands to the rover in a morning "uplink" and gather data in an afternoon "downlink." During an uplink, the rover is told where to go, but not exactly how to get there. Instead, the command contains the coordinates of waypoints toward a desired destination. The rover must navigate from waypoint to waypoint without human help. The rover has to use its "brain" and its "eyes" for these instances. The "brain" of each rover is the onboard computer software that tells the rover how to navigate based on what the Hazcams (hazard avoidance cameras) see. It is programmed with a given set of responses to a given set of circumstances. This is called "autonomy and hazard avoidance."

Q) I want to be part of a manned mission to Mars when I am older. What books would you recommend on this subject?
A) Sheri Klug, Director of the Mars Education Program at Arizona State University, recommends the following:

Q) What will humans need to live on Mars?
A) Humans basically will need what they need on Earth to live: this certainly includes liquid water which is required by all living things as we know them; we will need oxygen at the right pressure so we can breathe; we need food; and, finally, 'comfortable' temperatures. For a few hours, this can be provided in space suits for people working on the surface of Mars, as is routinely happening in space close to the Earth when astronauts work outside the Space Shuttle or the Space Station. But, to live in a convenient environment on Mars for a longer time, 'high tech' buildings (so-called 'habitats') are needed which can hold the air for people to breathe. Oxygen for this air could be generated on Mars from rock and soil that is found there. Water could be excavated as ice from below the surface that is then brought into the habitat to be melted. Energy for heating could be produced by solar cells, using light from the sun. Food, however, may have to be brought from Earth at first, but later on farming could be started inside the habitat.

Q. How were the rovers named?
A. NASA conducted an essay contest to name the rovers. The winner was Sofi Collis, a 9 year old from Scottsdale, AZ. She announced the winning names "Spirit" and "Opportunity" with NASA Administrator Sean O'Keefe on June 8, 2003.

Q. Why did you name your website Athena?
A. Athena is the name given to the science instruments on board the Mars Exploration Rovers. Each instrument has its own name, but when scientists want to refer to all the science instruments together, they say "the Athena Science Payload." The name Athena was chosen because it is the name of the Greek goddess of wisdom. She was also a goddess of war, and the female counterpart to Ares (Mars).

Q) Why is Mars so cold?
A) Mars is cold because it is much farther from the Sun than Earth. Because of this, Mars receives about 2.5 times less solar energy than Earth.

Q) How long is one year on Mars?
A) The definition of "one year" for any planet means the length of time it takes for that planet to make one orbit around the Sun. A year on Mars equals 687 Earth days.

Q) Why is Mars red?
A) Mars is red because it is rusting. There is a large amount of oxidized (rusted) iron in the soil. Oxidized iron can look brown, yellow, orange or red depending on the amount of oxidation that has occurred.

Q) How long does it take to get from Earth to Mars?
A) The distance between Mars and Earth is constantly changing since both planets are orbiting the Sun at different rates and are at different distances from the Sun. For the 2003 mission, it will take 7 months to reach Mars.

Q) What is Mars made of?
A) Like Earth, Mars is probably made up of many different types of rocks. On the surface, there may be a large amount of basalt, which is a volcanic rock. There could be other rocks in the mantle and crust of Mars, iron and nickel at the planet's core, and different minerals in the wind blown dust. But we don't know for sure. That's why we continue to send missions to Mars.

Q) Can people live on Mars? If they can't now, will they ever be able to?
A) The atmosphere on Mars is too thin and contains too much carbon dioxide to support human life. It is very cold on Mars and there is no liquid water on the surface. It is an extremely harsh environment for humans. They could not live on Mars without life support equipment.

Q) Is there water underground on Mars? Is there life underground?
A) There is definitely water ice underground at the polar regions of Mars and possibly liquid water at even greater depths, but we don't know for sure. We also do not know if there is life beneath the surface of the planet.

Q) Why does everything weigh less on Mars?
A) The larger the mass of the planet, the greater the gravity. Because Mars is much smaller and less massive than Earth, it has less gravity.

Q) Why are kilograms used in the "Weight on Mars" calculator if kilograms are a measure of mass?
A) Indeed kilograms are a unit of mass, not weight. However, common usage around the world is to quote weight in kilograms. The decision was made that kilograms would be more familiar to visitors of the page.

Q) How big is Mars compared to Earth?
A) Mars is smaller than the Earth. Its mass is 11% of Earth's mass and its diameter is about half the size of the diameter of Earth.

Q) Has anyone ever set foot on Mars?
A) No human has ever set foot on the surface of Mars.

Q) Are there plans for a manned mission to Mars?
A) People have thought about going to Mars for many years, but there are no firm intentions to send humans to Mars in the near future.

Q) Where did Mars get its name?
A) The ancient Greeks were fascinated by Mars. Its blood red color led them to attribute the planet to Ares, their god of war. When the Romans conquered the Greeks, they renamed the gods and the planet Ares became the planet Mars.

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