Mars : The Great Red Planet

Birth of Mars and the Missions to it

Information is correct as of October 1997

Mars is the closest planet to us and has the most possible signs of life. Many missions have gone to Mars, some were successful and some were not. I will also give my opinion on what I think will happen in the future to Mars.

The solar system formed from the condensation of a primitive nebula or the disk shaped cloud of gas that surrounded the newborn sun. The planets did not form directly from the dust of the nebula, but from many other small objects, up to bodies with a diameter exceeding 1000 km. The heat generated by the impact of large bodies may lead to magma oceans and to core formation. Core formation by gravitational segregation of metallic iron goes together with the growth of planets. The shape of the planets are consistent with the collisions of very large objects like comets and other large things.

The smallness of Mars suggests that the planets formed after the formation of Jupiter was more or less completed. The increase in the relative velocity among the beginning of the planets because of the presence of Jupiter prevented a full and total growth in the Mars feeding zone and the birth of a planet in the asteroidal zone. The early stages of evolution are probably when the main features of the planets were formed except from core formation. This refers to the formation of the crust and crustal dichotomy or the large apparent difference in crust thickness between the northern and southern hemispheres of the planet. The latter may be a consequence of a giant impact or may be of tectonic origin. Crust formation by mantle through partial melting must have been very speedy and strenuous early on when the southern hemisphere formed but the speed of it was reduced dramatically in the later evolution when endogenic activity was only going on in the northern hemisphere. The formation of the crust affected the evolution of the underlying mantle since the crust formation works together the transfer of radiogenic elements and other incompatible elements from the mantle to the crust. The model calculations that have been done also suggest that Mars has a magnetic field in its early evolution. This magnetic field was powered by the heat lost from the core to the mantle. As the core cooled, the field would have decreased and eventually would have ceased.

Although the planet and its elements are less evolved, Mars is more like Earth than the Moon and Mercury which makes it a perfect target in the search for life on other planets. Excluding Earth, Mars is the only other planet of the Solar System that has a transparent atmosphere, which means you can see through it, with surface temperature conditions in the range of the stability of complex organic compounds. That reason also makes it an obvious target in the search for present or extinct life forms.

Mars shows a wide variety of surface features formed by exogenic processes whose controlling factors are distinctly different than the same factors of Earth (Formation 1). Mars is smaller and, because of its greater distance from the Sun, cooler. It has seasons similar to Earth's because the tilt of its rotational axis (axial inclanation) to the plane of its orbit about the Sun is about the same as Earth's. Unlike Earth the eccentricity (elliptical shape) of the Martian orbit means that the seasons of Mars are also affected by the varying distance from the Sun. In the case of Earth, because of its almost circular orbit, our seasons result simply from the tilt of the Earth's rotation axis (Comparison 3).

The Mars Pathfinder is the second of NASA's low cost planetary Discovery missions. The mission consisted of a lander and a small surface rover, which was launched in late 1996. The mission was intended to develop technology and capabilities for low-cost landings on and exploration of the Martian surface rather than being driven by missions preprogrammed into the craft ("Mars Pathfinder" 1).

The mission's main purpose is to demonstrate technologies and concepts for eventual use in future missions to Mars that use scientific landers. Pathfinder also brought science instruments to the surface of Mars to investigate the structure of the Martian atmosphere, surface meteorology, surface geology, form, and structure, and the elemental composition of Martian rocks and soil. In addition a rover, that could possibly go anywhere the pilot on earth wanted it to go, is deployed to conduct technology experiments and to serve as an instrumental deployment mechanism ("Mission Summary" 1).

The scientific objectives were to retrieve atmospheric entry science and detailed characterization of the landing site by an advanced imaging system and a chemical analysis experiment mounted on the rover. The spacecraft entered the Martian atmosphere directly and, after it lost most of its energy in the upper atmosphere, landed on Mars with the aid of parachutes and rockets (to slow the decent) and air bags (so it can bounce along the surface of the Martian planet and not get hurt). After landing, the spacecraft unfolded itself from within a triangle shaped structure that has three triangle solar panels ("Mars Pathfinder" 1).

The landing didn't go exactly as the scientists had planned. On July 5, 1997 NEWS.COM reported this,

The six-wheeled rover called Sojourner was scheduled to start exploring the Martian landscape yesterday, but the cushion of air bags that deployed when the spacecraft landed didn't fully retract. Today controllers at Jet Propulsion Laboratory in Pasadena were able to move the part of the air bag that was blocking the path of the rover. Scientists lifted up one of the probe's three solar panels to a 45 degree angle, then simply set it back down. The air bag that had been draped over the solar panel is now completely out of the way. But after fixing that problem, scientists were faced with another communications glitch between the Pathfinder and the rover. The problem was corrected this afternoon by 'turning the modems in the spacecraft off and on repeatedly', reported the Associated Press. NASA scientists said 'it is vital they fix the problem so the Sojourner rover could start collecting data about the planet. The tiny rover has to communicate any data it collects through pathfinder'. Controllers are now studying new photos from the Pathfinder to decide which ramps they will use to deploy the rover. The rover is expected to be deployed sometime later today, and will begin creeping over Mars' surface at a speed of 80 feet per hour. ("Mars Probe" 1)

The lander first transmitted the engineering and science data collected during entry into Mars's atmosphere after landing which the stereo/color imaging system obtained a panoramic view of the landing area and transmitted it to Earth. After all the problems were solved and they performed a systems check, the rover was deployed to examine and measure the composition of individual rocks near the lander.

Over 2.5 square meters of solar cells used together with rechargeable batteries powered the lander. The main lander components are held in the triangle shaped unit in the center of the three petals. This is where the three low gain antennas are extending from three corners of the box and the camera extending up from the center. The rover was stowed against one of the petals ("Mars Pathfinder" 1).

There are also two other missions to Mars that aren't totally completed yet. Those programs are Mars Global Surveyor program or (MGS) and a Russian program called Mars-96. These are the projected objectives that the scientists want the programs to carry out.

Mars-96 is a Russian mission scheduled to be launched on November 16,1996, from the Baikonur Cosmodrome. Arrival at Mars will be on September 12, 1997. Mars-96, originally known as Mars-94, has in it a large Orbiter and several small landers. A single spacecraft will be launched during this. The major scientific objectives of this mission are to investigate the evolution of Mars, that is, the evolution of its atmosphere, surface, and interior. During cruise to Mars, interplanetary space parameters will be measured and some astrophysical observations conducted (Moersh "Mars-96" 3).

The Mars Global Surveyor is the first mission in NASA's Mars Surveyor series. Mars Global Surveyor is an orbiter carrying five of the seven investigations originally on-board the Mars Observer mission which died. The payload includes an orbital camera, thermal emission spectrometer, ultra-stable oscillator, laser altimeter, magnetometer/electron reflectometer, and a Mars relay system.

Mars Global Surveyor will be in polar orbit around Mars. It is designed to provide global maps of surface topography, the distribution of minerals and measurements of atmospheric dust and clouds. Launched with the Delta-2 rocket in November 1996, the spacecraft will cruise ten months to Mars (arriving in September 1997), where it will be inserted into elliptical capture orbit. During the following four months, aerobraking techniques will be used to reach the nearly circular mapping orbit over the polar caps. Aerobraking, is a technique pioneered by the Magellan mission, which uses the forces of atmospheric drag to slow the spacecraft, in turn reducing the amount of fuel required to reach low Mars orbit. Mapping operations are expected to begin in late January 1998 (Moersh "Mars Surveyor" 1).

I think the future of Mars is great. I say in about a decade the people of the Earth will start populating Mars. Once overcrowding of the Earth becomes serious a lot more people will start to move to Mars. In about two centuries we will have made the atmosphere of Mars livable. Eventually after we inhabit Mars we will have the technology to inhabit other planets. There have been many missions to Mars. We have learned a lot from these missions. Hopefully in the years to come man will venture into unknown territory and step foot on Mars.

Works Cited

"Comparison Between Mars and Earth Characteristics." 3 pp. Online. Internet. 1 November 1997. http://cmex-www.arc.nasa.gov.

"Formation and Early History of Mars." 2 pp. Online. Internet. 1 November 1997. http://helio.estec.esa.nl.

"Mars Pathfinder." 1 p. Online. Internet. 1 November 1997. http://mars.pathfinder.gov.

"Mars Probe Runs Into Trouble." 1 p. Online. Internet. 1 November 1997. http://oberon.ibsys.com.

"Mission Summary." 1 p. Online. Internet. 1 November 1997. http://zerblatt.forex.ee.

Moersch, Jeffrey."Mars-96." 3 pp. Online. Internet. 1 November 1997. http://www.marsmissions.com.

---. "Mars Surveyor Program." 3 pp. Online. Internet. 1 November 1997. http://www.marsmissions.com.