Spacecraft to Mars Phase 1
The Mariner Spacecraft to Mars
|
The first spacecraft to successfully reach Mars and return useful pictures was Mariner 4. This 261 kg spacecraft, equipped with a camera and digital tape recorder, flew by the planet on July 14, 1964. And everything changed. Returning a whopping 22 (!!) pictures (many so poor as to be useless, it revolutionized our understanding of the planet.
|
|
The images returned by Mariner 4 presented scientists with
a bleak picture |
Here is a little Quicktime movie I made of the 22 Mariner 4 photos. PDF-ers: Mariner4/Mariner4.mov
But the Mariner program was designed to do more than answer this one question. It was meant to explore Mars so that we could understand it as a real place, not just a fuzzy ball viewed through telescopes here on the Earth.
Mariner 6 & 7
|
Mariner 6 and 7 were launched in 1969 for a second flyby encounter with the Red Planet. Mariner 6 passed Mars on July 31, 1969, and Mariner 7 5 days later.
|
|
Mariner 6 Far Encounter Movie http://members.tripod.com/petermasek/m67ex14.html
Each mapped a different region of the planet
|
|
Mariner 6 image.
More craters……
Some craters, like that at the lower left of this image, are nearly obliterated |
|
Another shot by Mariner 6,
This image includes the boundary between the darker Sabaeus Sinus region and the lighter Deucalioness Regio. Analysis of crater counts indicates that the two regions have the same crater density, and are thus are of approximately the same age |
|
|
|
Mariner 7 was targeted to cover the south pole of Mars, which is in the lower left corner of this image. The South Polar Cap (SPC) is also visible here. |
While both spacecraft returned excellent (for that time) images, the impression created by Mariner 4 was not changed, only enforced. Mars seemed as dead as the Moon. There seemed little chance of finding anything resembling living organisms here, and even the hope of finding evidence for past life vanished.
Still, the three successful Mariners had all photographed only limited regions of mars, and all in the southern hemisphere.
The situation changed with the arrival of Mariner 9.
Mariner 9 
Obviously, you can get more pictures with a spacecraft orbiting a planet for months than you can with a flyby lasting only a few hours! However, it initially looked as though the Mariner missions were jinxed. Mariner 8 failed upon launch on may 8, 1971. Mariner 9, launched on May 30, arrived at Mars during the middle of a planet-wide dust storm, so there was nothing to photograph!
Luckily, after a few weeks, the dust began to settle (literally), and its work could begin. And once again, our vision of Mars was changed. Armed with wide- and narrow-angle cameras, UV and IR spectrometers, Mariner 9 may be responsible for our most profound change in understanding Mars.
|
At last! Long features that looked like water channels. However, they did not occur where the “canals” were supposed to be! However, it was now apparent that water once flowed on the surface of Mars, despite the fact that present conditions make that very difficult over extended periods of time. Mars was once a warmer and wetter place than it is today |
|
|
|
Perhaps one of the most famous images ever obtained of a planet, Mariner 9 obtained this image of Olympus Mons, a giant volcano whose base is the size of Ohio. Mars was also volcanically active for some time in its past. It takes quite a bit of time to build a mountain this big! |
|
Numerous pits found near the south polar region of Mars suggested collapse due to thawing of underground ice. |
|
|
|
More collapsed features, this time in a network pattern. |
The tremendous variety of features seen on Mars from Mariner 9 forced planetologists to develop a whole new vocabulary to describe what was seen. Here are some of terms used:
|
Chasma: a steep-walled trough or canyon (this is where the term "chasm" comes from). Example - Coprates Chasma, part of Vallis Marineris, 14S 60W.
Fossa: trench or channel. Example - Tantalus Fossae (note the pluralization), 40N 105W.
Labyrinthus: labyrinth-like structure (as in the Labyrinth in Crete constructed by Deadalus, according to Greek mythology). Example - Noctis Labyrinthus, 5S 100W.
Mensa: Mesa-like feature, rising from lower elevations and topped with flat tops. Example - Nilosyrtis Mensae, 35N 290W.
Mons: mountain. Example - Olympus Mons ("Mount Olympus"), 18N 133W.
Patera: saucer or shallow dish. Example - Alba Patera, 40N 110W.
|
|
Planitia: plain, in this case to indicate a large low-lying region. Example - Hellas Planitia "Hellas Plain", named after the ancient Greek word for their homeland), 45S 290W.
Planum: flat, high plain. Example - Solis Planum ("Plain of the Sun"), 25S 90W.
Tholus - dome, usually used to describe a dome-like mountain or hill. Most are probably volcanic in origin. Example - Arbor Tholus, 19N 210W.
Vallis: valley. Example - Vallis Marineris ("Valley of the Mariners" named for the Mariner spacecraft - this feature was first observed in 1969 using the Mariner 9 spacecraft), 10S 40-100W.
Vastitas: widespread lowlands. Example - Vastitas Borealis ("Northern Wasteland"), close to the north pole.
|
Impact Craters are named after scientists, philosophers, etc. By convention, martian surface features named for persons (real or imaginary), such craters, are male (those on Venus, with one or two exceptions, are female). All names are decided by the International Astronomical Union (IAU). Example: Mitchel (68S 284W) is named for O.M. Mitchel, the founder of the Cincinnati Observatory.
To find out more about these and other NASA missions to Mars, visit the NASA Mars Missions web site.
http://marsprogram.jpl.nasa.gov/missions/
We will look at more missions now.