August 26, 1999:
July 20, 1999:
October 15,1997: NASA begins its seven year mission to explore Saturn.
October 2,1997: Forty years after Sputnik first circled the Earth, historians examine its impact.
September 30,1997: An interview with Mir astronauts.
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If things had gone right, the Mars Polar Lander would have started to dig in the planet's hard ground Tuesday.
But it looks like it will be a few years before we see the south pole of Mars and listen to Martian winds.
After 11-months and 470 million miles, the Mars Polar Lander (click for animation) was due to land Friday. It would have been the fourth U.S. spacecraft to set down on Mars.
Radio signals confirming the Lander's touchdown haven't reached Earth, and scientists are getting nervous. If the $165 million probe failed, Congress may cutback on funding for space exploration.
Exploring uncharted waters
The Lander had "arms," "eyes" and "ears" to explore the planet. One mystery we hope to solve is what happened to the water on Mars?
The Martian surface is covered with deep channels carved by water. It looks like there were rivers and even oceans sometime in the past. There is some ice on the surface, but not enough to explain the grooves.
Finding the water will offer clues to whether life existed or still exists on Mars. Also, if water is found, engineers could use it to generate rocket fuel on Mars for future missions.
Many believe water is hidden below the surface. The question is, how far down?
The 3½-foot tall Lander had a robotic arm to dig into the planet, scoop soil samples and look for trapped water and other materials.
Like on Earth, as you dig in the ground, you go back in time. As spacecrafts on Mars burrow below the surface, they are sifting through layers of material built up over long periods of time. Scientists hoped to find out what was on the planet 100,000 years ago.
The Lander's "eyes" were a camera, which was to take close pictures of the soil, looking for clues. And the "ears" were a microphone on the deck, which would have made the first recordings of sound from another planet.
(click for more on the technology of the probe)
Problems phoning home
Communications between the Mars Polar Lander and Earth were complicated by the loss of another spacecraft, the Mars Climate Orbiter. The Orbiter was supposed to act as a go-between in communications between crafts on Mars and scientists on Earth. In September, it was lost in space.
The Orbiter "disappeared" because of human error. Flight controllers at the company who made the craft gave important data in English units, like inches, when it should have been in metric units, like centimeters. The data was used to compute very, very small little thrust pulses onboard the spacecraft. The mistake made the pulses one fifth of what they needed to be. And that in turn made it very difficult to get the proper navigation, or determine the position and velocity of the spacecraft, which eventually led to failure.
The loss of the Orbiter hurt this current mission's ability to transmit information from the Lander home to Earth.
It takes more power to operate a direct Mars-to-Earth link. The Lander had to push information all the way from Mars back to Earth instead of to an orbiter that's just overhead, and that takes more power.
Looking towards future missions
No follow-up polar mission is planned. But in five or six years, scientists on earth are hoping to be able to study bits and pieces of Mars in their own labs.
The 2003 Mars Surveyor will be equipped with a rock-collecting Rover.
The Rover will use a drill to acquire soil and rock samples and then put them in a container on the nose cone of a rocket. The rocket will launch into orbit around Mars. They will be picked up in 2005 by an orbiter currently being built by the French and they will reach Earth by 2008.
Posted December 7, 1999
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