| Topic: U.S. Missions to Mars I) Introduction I chose to write my case study on the missions to Mars because like many others, I am intrigued by the planet's many possibilities. There has been much speculation surrounding the prospect of life on Mars since it was discovered. Although we now realize that Mars isn't a planet teaming with intelligent life, I still find it exciting to ponder what they could find someday. Scientists have already discovered many things, including the potential for past life. However, we won't know for sure until we can investigate the planet a little closer. With Mars, the key to discovery has been, and will be, the technology we use to provide us with answers. An obvious rule is that as technology gets better, we learn much more. Technology is so important because we rely on it to answer our many questions about science. Technology has made a significant impact on our understanding of Mars and continues to provide more hope for future discovery. My case study will provide insight into the evolution and development of the technology that is designed to further our understanding of the Red Planet- the space missions. I will also include policy-related issues that NASA has to deal with due to missions and their outcomes. II) Facts: The Evolution and Development of Mars Missions Before I started my research on this subject, I was only aware of a few of the Mars missions such as the Mariner, Viking, and Pathfinder. I was amazed to find that there were actually 14 missions and many more on the drawing board! They started about 40 years ago and continue to be developed. At NASA's website for the Mars exploration program (http://mars.jpl.nasa.gov/), I found the chronology of Mars exploration. From this, I created a table of the US missions that are the subject of my case study assignment. The table serves as a reference throughout section II which provides information about the various missions. According to the table, not all the missions were successful. The technology used for any mission is very much advanced and very complex. However, for the missions that were considered successful, scientists gained even more knowledge about Mars. Let's take a look at the space probes and their missions to see what they were all about. The Mariner's (1964-1971 Launch Dates) The Mariner family of space probes actually started with Mariner 1 and 2, which were destined for the planet Venus. The true heritage of the probes can actually be traced back even further to NASA's two Ranger missions intended for the moon and possibly Venus. But Mariner 3 and 4 were paired and designed specifically for the planet Mars. In the early days of space missions, NASA built their probes in pairs with very close launch dates. As you can see from the timeline above, this was the case all the way through the Viking missions. Later missions became very complex and therefore very costly; so only one of each type of probe (for Mars) was actually built after the Viking missions. This pairing of space probes actually turned out to be a good thing for the sake of successful endeavors with Mars. In fact, the first of the two probes (Mariner 3), never made it to Mars. It was launched into space but a protective fairing prevented it from spreading its wings. But Mariner 4, launched on November 28, 1964, was a great success! The probe came within 6,085 miles of the planet and took the first close-up pictures of its surface (Wilson 84). At this point in space history, the NASA engineers were very pleased but the scientists were not. Although the probe did what it was supposed to do, the images of Mars didn't exactly reveal an environment suitable for life! The surface was barren and pitted with craters much like our moon. Subsequent Mariner missions to Mars were improvements over the first. Mariner 4 could only take pictures of a very small portion of the planet. Mariners 5 and 6 had more advanced imaging systems and other equipment yielding an even better look at the planet's surface. Mariners 8 and 9 were the final Mariner missions to Mars. Like the first mission, Mariner 8 suffered technical problems that caused it to end its journey in the Atlantic. However, on May 30, 1971, Mariner 9 successfully made its way to Mars. Unlike the other "flyby" missions to Mars, Mariner 9 became the first man-made satellite of another planet. (Wilson 87) The sophistication of the later Mariner missions provided more detail about Mars and its inability to support life. It was further disappointment to the scientists since the new images revealed more of the same type of terrain. It appeared to be a world unlikely to support any type of life form. The Vikings (1975 Launch Dates) The Viking missions were designed to provide a much more in-depth analysis of the Planet Mars. Vikings 1 and 2 both contained two separate components, an orbiter and a lander. The primary mission objectives were to obtain high-resolution images of the planet's surface, define the structure and composition of the atmosphere and surface, and then most exciting- search for evidence of life! These two missions turned out to be very successful in terms of information gained about the Martian world. Although no signs of life were found, scientists gained a wealth of information. The outcome is explained well through NASA's website on Mars exploration: The results from the Viking experiments give our most complete view of Mars to date. Volcanoes, lava plains, immense canyons, cratered areas, wind-formed features, and evidence of surface water are apparent in the Orbiter images. The planet appears to be divisible into two main regions, northern low plains and southern cratered highlands. Superimposed on these regions are the Tharsis and Elysium bulges, which are high-standing volcanic areas, and Valles Marineris, a system of giant canyons near the equator. The surface material at both landing sites can best be characterized as iron-rich clay. Measured temperatures at the landing sites ranged from 150 to 250 K, with a variation over a given day of 35 to 50 K. Seasonal dust storms, pressure changes, and transport of atmospheric gases between the polar caps were observed. The biology experiment produced no evidence of life at either landing site. (NASA) The success of the Viking missions came at a price. In fact, it turned out to be the most expensive planetary mission ever, costing over $3,000m (Wilson 91). As we will see later, there is a strong correlation between mission price tag and mission outcome. Mars Observer (1992 Launch Date) It had been 17 years since the Viking missions were launched providing us with unprecedented detail about the red planet. The Mars Observer mission turned out to be very frustrating from an engineering and scientific perspective. I remember waiting for this one only to be disappointed myself when hearing that the probe went silent just before reaching the orbit of Mars. The mission was full of objectives including these primary ones listed at the JPL Mission and Spacecraft Library: -Determine the global elemental and mineralogical character of Mars' surface material -Define the planet's global topography and gravitational field-Establish the nature of the Martian magnetic field -Determine the time and space distribution, abundance, sources and sinks of volatile material and dust over a seasonal cycle -Explore the structure and aspects of the circulation of the Martian atmosphere -Explore the structure and aspects of the circulation of the Martian atmosphere Communications was lost with the Observer on August 22, 1993 (JPL). Unfortunately, no scientific information was received. Global Surveyor (1996 Launch Date) The Global Surveyor mission was to recover the lost objectives from the failed Observer mission. It is currently orbiting the planet, scanning it with cameras and other sensors, and charting the Martian landscape. It is interesting to note, among its other objectives, the Surveyor's prospect for life on Mars. A 1997 special report on the CNN Interactive website reveals the excitement relating to the search for Martian life: Global Surveyor's mission is to compile global maps of Mars, as well as collecting data on its atmosphere, surface composition, interior and evolution. Surveyor will help identify the likeliest sites where life might have taken hold on the planet. Those include areas where there once was water, such as lake shores and mineral remains of ancient hot springs (Zarrella). To date, the possibility of life on Mars is still speculation based on evidence found that water was once present on the surface. Scientists believe that water is a necessary component for the development of life, like here on Earth. Mars Pathfinder (December 4, 1996 Launch Date) This is one of my favorite missions. I remember watching (for hours) as the story unfolded; it was a very exciting time. I couldn't wait to see the first images of Mars from this mission! The Pathfinder mission consisted of a stationary Lander and a surface rover named "Sojourner". The spacecraft entered the Martian atmosphere without going into orbit around the planet and landed on Mars with the aid of parachutes, rockets and airbags. The landing was unique in that it bounced on the surface on its airbags until it came to rest. Then, three triangular solar panels (petals), unfolded onto the ground after touchdown (NSSDC). Eventually, a ramp was lowered and the Sojourner made its way down to the ground so it could cruise around and investigate geological features of the planet. The Pathfinder mission had very specific objectives relating to the cost of planetary exploration. I will cover the NASA policy issues later in the case study. But the Pathfinder mission was a significant milestone in terms of NASA's new objectives in the area of planetary exploration. Direct from the NASA website, here are the mission objectives: -Mars Pathfinder is a NASA Discovery Mission -"Faster, better, and cheaper" with three years for development and cost under $150 million dollars -Demonstrate a simple, low-cost system, at fixed price for placing a science payload on the surface of Mars at 1/15 the Viking price tag -Demonstrate NASA's commitment to low-cost planetary exploration by completing the mission for a total cost of $280 million dollars including the launch vehicle and mission operations -Demonstrate the mobility and usefulness of a micro-rover on the surface of Mars (NASA) The scientific objectives included atmospheric entry science, long-range and close-up surface imaging, with the general objective being to detail the Martian environment for further exploration. The Lander and rover operated until communication was lost for unknown reasons on 27 September (NSSDC). Mars Climate Orbiter The Mars Climate Orbiter is part of NASA's 10 year Mars Surveyor Program which will launch missions every 26 months when the alignment of Earth and Mars are ideal. It was intended to gather information about the Mars climate including the following: -Monitor the daily weather and atmospheric conditions -Record changes on the Martian surface due to wind and other atmospheric effects -Determine temperature profiles of the atmosphere -Monitor the water vapor and dust content of the atmosphere -Look for evidence of past climate change -Specifically it will observe and study dust storms, weather systems, clouds and dust hazes, ozone, distribution and transport of dust and water, the effects of topography on atmospheric circulation, atmospheric response to solar heating, and surface features, wind streaks, erosion, and color changes (NSSDC) Unfortunately, this information was never obtained. Contact was lost with the Orbiter soon after it reached the planet. The investigation revealed that navigation commands were sent in English units instead of being converted to metric. This caused the probe to enter the Martian atmosphere much lower than intended. The craft would have been destroyed by stress and friction with this low of an altitude. Another disappointment from an engineering and scientific standpoint. Mars Polar Lander (1999 Launch Date) Like the Mars Climate Orbiter, the Polar Lander was also a part of the Mars Surveyor Program. And like the Orbiter, the Polar Lander experienced problems rendering it a failed mission. The Lander was to land on the South Pole of Mars and study climate related attributes in the region. Its mission was very similar to that of the Orbiter. But communication was lost with the Lander just before it reached the atmosphere of Mars. The cause of the problem is not known. At this point, NASA is really beginning to feel the heat over its recent mission losses. Deep Space 2 (DS2 1999 Launch Date) The DS2 mission was actually composed of two probes that were intended to analyze subsurface features of Mars. This latest attempt to understand more about the Martian environment had many scientific purposes such as the following listed at NSSDC: -Test for the presence of water ice below the surface, and if ice exists, attempt to resolve the mineral phases in which the ice is stored -Determine the thermal and physical properties and temperature gradient of the subsurface material -Measure the atmospheric pressure and temperature -Data was also to be obtained on the atmospheric density profile and near-surface soil stratification using deceleration measurements during atmospheric entry and landing -The mission was also planned to serve as a technology test for many of the components of the probes and a demonstration of passive atmospheric entry and survivable hard impact. But again the results were very discouraging. Contact was lost before the probe reached the Martian atmosphere. Another setback for NASA and scientists. At this point in my case study, an overview of NASA policy is in order to understand the issues behind the recent mission failures. IV) Analysis: NASA Policy Issues By now it is obvious that NASA is having some technical difficulties! As I mentioned during my overview of the Viking missions, there is a strong correlation between mission price tag and mission outcome. NASA simply does not have the funding that it used to. The most common argument I see from the side of NASA (because of mission failures) has to do with its recent policy known as "faster, better, cheaper". NASA began to feel the effects of budget constraints during the Nixon administration. The plan was to follow the Apollo missions with manned missions to Mars in the 1980's. However, Nixon's administration rejected the proposal submitted in 1969. The Viking missions became the only means for exploration of the planet. However, the Viking's were still the most expensive space missions and were unequalled in their scope. They operated almost flawlessly for years, providing a wealth of information (Wilson 91). Today's NASA objectives are very much restrained by the new policy of "faster, better, cheaper". In addition, their embarrassments continue to pile up as they go. An excerpt from a recent article in Popular Science by Michael Carroll, sums up the situation well: Failures of Mars Climate Orbiter, Mars Polar Lander, and twin Deep Space 2 probes have brought NASA's "faster, better, cheaper" approach under attack. But a study by the Mars Program Independent Assessment Team concludes that "properly applied, [it is] an effective concept that should continue." At the same time, the team found "significant flaws" in NASA's Mars program. The report states that the current organization at NASA's Jet Propulsion Laboratory "is not appropriate to successfully manage the Mars program in combination with other commitments." JPL missions have skyrocketed from an average of four or fewer each year to a current high of 10 to 15 concurrent programs. Despite increased workloads, staffs have been reduced. The report describes the missions as "significantly underfunded for the established performance requirements." (Carroll) Much of what I see has to do with the outcome of budget cuts such as understaffing, increased workloads, and limited project time. NASA's new policy of "faster, better, cheaper" was set forth in 1993 by NASA Administrator Daniel S. Goldin. This new policy called for an end to the billion-dollar, interplanetary space missions of the past. The new way of life is to send smaller ships out more often. Even though there were successes under the new program (such as the Pathfinder), many other missions have been troubled. After NASA instituted the program of sending spacecraft to Mars every two years, the fear was that there wouldn't be enough money to do the job right (Schefter 58-59). And as we have seen, they may be right. Much of the blame appears to be aimed at NASA management. According to a report cited in the online publication, SpaceViews, "the Mars Climate Orbiter and Mars Polar Lander, lacked the necessary oversight, testing, and independent analysis needed to ensure successful missions." A report issued by the Mars Program Independent Assessment Team (headed by former Lockheed Martin executive Thomas Young) turned up some interesting conclusions relating to NASA management: Both the failures of Mars Polar Lander and Mars Climate Orbiter, which was lost when a mixup in units between JPL and Lockheed Martin caused the spacecraft to drift off-course burn up in the Martian atmosphere last September, could have been prevented with appropriate testing and oversight, the panel concluded. "Mistakes were made in areas where we know how to do things correctly," said Young. The lack of proper management stemmed from rigorous cost and schedule limitations on the program. The success of the Mars Pathfinder mission, which cost approximately $250 million, led NASA to believe it could then do the two Mars Surveyor 1998 missions for about the same cost. (SpaceViews) So overall, the new policy certainly is a factor in the recent technical problems experienced by NASA. I found amusing the irony pointed out in the March 2000 Huntsville Times article, Congress, Mars, & NASA. It exclaims: Ironically, some members of Congress are making ominous noises about the two Mars mission failures. They wonder if ''faster, better, cheaper'' is really working. Well, if it's not, they need look only so far as the nearest mirror. NASA adopted this approach in order to keep exploring the planets, and it's trying to do it at a cost Congress will accept. (Alabama) Probably enough said about faster, better, cheaper! We'll have to see what's in store for NASA and the future of the space program. V) Conclusion In spite of all the problems, NASA has brought us information about another world that we didn't, or couldn't know before. Their technological advances are invaluable to our current understanding of Mars. We now know that it's mostly a barren world, free of any advanced civilizations. However, we're still not sure that there isn't some form of life there; or that it once existed. If NASA can continue to push the boundaries of technology, we will continue to learn more about the Martian world. There will always be problems with technology; it isn't perfect. This goes for any industry, not just space exploration. I think it's more the nature of NASA technology that gets people excited. And that goes for when things are good, and when things are bad. We look forward to discovery, and in this case, the price is truly high. Even if we don't find life on Mars, eventually we will "put" life on Mars. Much of the purpose of the NASA missions is to understand what the planet has to offer in the way of life-sustaining properties. The distant future plan is to actually colonize the planet. However, there is much work to do up front. As we have seen, we have a long way to go with technology before that will happen. I sure wouldn't want to step on a manned probe destined to a planet that is millions of miles away. Not now anyway! VI) Works Cited Wilson, Andrew and Curtis Peebles and H. J. P. Arnold. Man in Space: An Illustrated History of Space Flight. New York: CLB Publishing, 1993. NASA. Mars Exploration Program. Missions. Internet: http://mars.jpl.nasa.gov/mep/missions/index.html. November 5, 2000 JPL. Mission and Spacecraft Library. Internet: http://samadhi.jpl.nasa.gov/msl/home.html. November 5, 2000 Zarrella, John, "Mars Global Surveyor Arrives at Red Planet." CNN Interactive: Sci-Tech Story Page. September 11, 1997. Internet: http://www.cnn.com/TECH/9709/11/mars.surveyor/ November 5, 2000 NSSDC. Planetary Sciences. Internet: http://nssdc.gsfc.nasa.gov/planetary/planetary_home.html. November 5, 2000 Carroll, Michael, "NASA's Jury is In." Popular Science. July 2000: 26. Schefter, Jim, "NASA's Changing Fortunes." Popular Science. April 2000: 56-61. SpaceViews, "Independent Panel Report Criticizes NASA Mars Program Management". March 29, 2000. Internet: http://www.spaceviews.com/2000/03/29b.html November 5, 2000. Alabama Live, "Congress, Mars & NASA." The Huntsville Times. March 24, 2000. Internet: http://www.al.com/news/huntsville/Mar2000/24-e24760.html November 5, 2000 Home |
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