How a Space Elevator Would Work

How a Space Elevator Would Work A space elevator is a proposed transportation system connecting the Earths surface to space. The elevator would allow vehicles to travel to orbit or space without the use of rockets. While elevator travel wouldnt be faster than rocket travel, it would be much less expensive and could be used continuously to transport cargo and possibly passengers. Konstantin Tsiolkovsky first described a space elevator in 1895. Tsiolkovksy proposed building a tower from the surface up to geostationary orbit, essentially making an incredibly tall building. The problem with his idea was that the structure would be crushed by all the weight above it. Modern concepts of space elevators are based on a different principle - tension. The elevator would be built using a cable attached at one end to the Earths surface and to a massive counterweight at the other end, above geostationary orbit (35,786 km). Gravity would pull downward on the cable, while centrifugal force from the orbiting counterweight would pull upward. The opposing forces would reduce the stress on the elevator, compared with building a tower to space. While a normal elevator uses moving cables to pull a platform  up and down, the space elevator would rely on devices called crawlers, climbers, or lifters that travel  along a stationary cable or ribbon. In other words, the elevator would move on the cable. Multiple climbers would need to be traveling in both directions to offset vibrations from the Coriolis force acting on their motion. Parts of a Space Elevator The setup for the elevator would be something like this: A massive station, captured asteroid, or group of climbers would be positioned higher than geostationary orbit. Because the tension on the cable would be at its maximum at the orbital position, the cable would be thickest there, tapering toward the Earths surface. Most likely, the cable would either be deployed from space or constructed in multiple sections, moving down to Earth. Climbers would move up and down the cable on rollers, held in place by friction. Power could be supplied by existing technology, such as wireless energy transfer, solar power, and/or stored nuclear energy. The connection point at the surface could be a mobile platform in the ocean, offering security for the elevator and flexibility for avoiding obstacles. Travel on a space elevator would not be fast! The travel time from one end to the other would be several days to a month. To put the distance in perspective, if the climber moved at 300 km/hr (190 mph), it would take five days to reach geosynchronous orbit. Because climbers have to work in concert with others on the cable to make it stable, its likely progress would be much slower. Challenges Yet to Be Overcome The biggest obstacle to space elevator construction is the lack of a material with high enough tensile strength  and  elasticity and low enough density to build the cable or ribbon. So far, the strongest materials for the cable would be diamond nanothreads (first synthesized in 2014) or  carbon nanotubules. These materials have yet to be synthesized to sufficient length or tensile strength to density ratio. The covalent chemical bonds connecting carbon atoms in carbon or diamond nanotubes can only withstand so much stress before unzipping or tearing apart. Scientists calculate the strain the bonds can support, confirming that while it might be possible to one day construct a ribbon long enough to stretch from the Earth to geostationary orbit, it wouldnt be able to sustain additional stress from the environment, vibrations, and climbers. Vibrations and wobble are a serious consideration. The cable would be susceptible to pressure from the solar wind, harmonics (i.e., like a really long violin string), lightning strikes, and wobble from the Coriolis force. One solution would be to control the movement of crawlers to compensate for some of the effects. Another problem is that the space between geostationary orbit and the Earths surface is littered with space junk and debris. Solutions include cleaning up near-Earth space or making the orbital counterweight able to dodge obstacles. Other issues include corrosion, micrometeorite impacts, and the effects of the Van Allen radiation belts (a problem for both materials and organisms). The magnitude of the challenges coupled with the development of reusable rockets, like those developed by SpaceX, have diminished interest in space elevators, but that doesnt mean the elevator idea is dead. Space Elevators Arent Just for Earth A suitable material for an Earth-based space elevator has yet to be developed, but existing materials are strong enough to support a space elevator on the Moon, other moons, Mars, or asteroids. Mars has about a third the gravity of Earth, yet rotates at about the same rate, so a Martian space elevator would be much shorter than one built on Earth. An elevator on Mars would have to address the low orbit of the moon Phobos, which intersects the Martian equator regularly. The complication for a lunar elevator, on the other hand, is that the Moon doesnt rotate quickly enough to offer a stationary orbit point. However, the Lagrangian points could be used instead. Even though a lunar elevator would be 50,000 km long on the near side of the Moon and even longer on its far side, the lower gravity makes construction feasible. A Martian elevator could provide ongoing transport outside of the planets gravity well, while a lunar elevator could be used to send materials from the Moon to a locatio n readily reached by Earth. When Will a Space Elevator Be Built? Numerous companies have proposed plans for space elevators. Feasibility studies indicate an elevator wont be built until (a) a material is discovered that can support the tension for an Earth elevator or (b) theres a need for an elevator on the Moon or Mars. While its probable the conditions will be met in the 21st century, adding a space elevator ride to your bucket list might be premature. Recommended Reading Landis, Geoffrey A. Cafarelli, Craig (1999). Presented as paper IAF-95-V.4.07, 46th International Astronautics Federation Congress, Oslo Norway, October 2–6, 1995. The Tsiolkovski Tower Reexamined.  Journal of the British Interplanetary Society.  52: 175–180.  Cohen, Stephen S.; Misra, Arun K. (2009). The effect of climber transit on the space elevator dynamics.  Acta Astronautica.  64  (5–6): 538–553.  Fitzgerald, M., Swan, P., Penny, R. Swan, C. Space Elevator Architectures and Roadmaps, Lulu.com Publishers 2015

Criminal Justice Research Essays

Criminal Justice Research Essays Criminal Justice Research Essay Criminal Justice Research Essay The educational system in America is deteriorating, which has lead students to failure and unrealized potential. Conversely, in Mike Roses essay, I Just Wanna Be Average he describes not only the problems with Vocational Education, but the effects it has on kids who spend their entire educational career in Voc. Ed. In Michael Moores essay, Idiot Nation he argues that the failures of the educational system and the lack of financing has been caused by the politics and the people who vote for them. Moore’s essay is more persuasive because he adopts a tone dripping with sarcasm and true passion for his cause. Mike Rose, in his anecdotal essay on education, describes not only the problems with Vocational Education, but the effects it has on students who spend their entire educational careers in these types of classes, who like himself, as a result of a high standardized test score allowed to take higher-level classes with more competent teachers. He illustrates these points by describing coping mechanisms that students develop to make up for their lack of a (real education). He also states that those who are knowledgeable, that they are (in the bottom) of the class, will be for the rest of their lives. Instead of receiving a higher education than average to make up for their learning disabilities, they receive a less-than-average education from under-qualified teachers. Rose also points out that the impact a teacher has on his or her students is very powerful. He states students will float to the mark you set (164) students will work harder if their teachers set the standards high. Throughout his excerpt, Rose shows through numerous examples that teachers are a vital part to a student’s success in life. Seeing Rose’s credibility in his story this quote was mentioned â€Å"I see nothing (in proposed regulations) for people striving for higher standards† meaning that he doesn’t see any reasoning to put all these rules and situations on someone’s plate if they are trying to better themselves or pushing for higher standards. Rose also clearly believes that every single student have a right and can reach their maximum potential, and rise to heir own expectations Rose’s purpose, therefore, is to bring to light the problems with this program and others like it to try to catalyze some change. He appeals to his audience by using cutting expression usage and conveying through irony and emotional appeal. Moore brings to light his view on the failures of the educational system and the lack of financing that has been caused from Pol iticians as well as American corporations contribute to the decline in education. His first major line of attack is the failed United States education system. Taking educational institutions at the federal municipal to a private level. Lamenting libraries without adequate books and modernized computer devices. Naming some United States Presidents that lacked knowledge of world geography. Arguing that the most powerful leader in the free world (an American president) should be knowledgeable about all 200 non-aligned and United Nations confederation member states. Moore mesmerizes his audience by presenting horrifying facts about the â€Å"state of stupidity in this country† (156). The facts that Moore presents are very effective due to the shocking nature of them. Early in the text Moore illustrates his point presenting, â€Å"There are forty-four million Americans who cannot read and write above a fourth-grade level- in other words, who are functional illiterates† (154). This stuns the reader, who would have ever thought that in a country like this, that many Americans could be, well stupid. He goes on to give another statistic that Americans, on average, read only 99 hours a year and watch television 1,460 hours a year. By throwing these astonishing facts at the reader early on, Moore builds up the trust of his readers and also holds their attention. Teachers are evaluated yearly in most municipalities. Tenured teaching career are being phased out. Therefore, Moore combines logical and emotional appeals when speaking on the devastating nature of the condition of some of America’s schools. Throughout the text, Moore uses harsh diction to get his point across. To some readers this may be offensive but when combined with the facts that Moore presents it makes his argument more convincing and powerful. The techniques Moore uses to make his argument convincing are very effective. The logical and emotional appeals as well as his harsh diction persuade the reader to agree with Moore in his argument on the stupidity and ignorance of the nation.

Case study analysis - will upload case study Example | Topics and Well Written Essays - 2500 words

Analysis - will upload - Case Study Example (Yoffie, 2009, p. 1) This notion quite obviously reflects the strategic decisions, which the two companies often come up with to capture the different unexplored segments of the market. However the carbonated soft drinks industry in the United States of America suddenly declined as the annual consumption of carbonated soft drinks decreased in US, and in the year 2004 it reached a constant low. (Yoffie, 2009, p. 1) The two companies definitely got affected by the downward trend of the industry, but in different ways. This particular case study analyzes the strategic management decisions that the two separate companies adopted, in the segments of bottling, pricing and brand promoting, in order to sustain their growth in the declining beverage market of United States. The focus is on the various strategic approaches adopted by the two cola companies in order to attain a desired position in the market. The strategic changes adopted by the two players in the case study ensure that the com petition or the cold war between the two will continue for the years to come. The foundation of Coca-Cola, which is the older of the two companies, dates back to the year 1886. A pharmacist named John Pemberton was the first to discover the formula for the potion and in the year of 1891, Asa Candler obtained the formula and with a specific objective started a sales force to distribute the product under the brand name of Coca-Cola. (Yoffie, 2009, p. 5) The first bottling franchise for the particular company was opened in the year 1899, and the growth rate was so substantial that within a gap of eleven years the company acquired about three hundred and seventy franchises in USA. (Yoffie, 2009, p. 5) With growth and popularity there were also direct threat to the brand image of Coca-Cola as there were an eminent number of imitators in the industry who