Instead, we view housing options on a spectrum that combines different elements of ownership, space, services and finance. In some cases, land may be public while the dwellings on it are private. This spectrum allows a more nuanced analysis of the reality of housing markets in the global south and consideration of a wider range of possibilities. While many challenges emerged, we focused on three that city officials can act upon and scale. Issue 1: The Growth of Informal or Substandard Settlements. As demand for housing has outstripped supply, informal and substandard settlements have proliferated. Since 1990, even as the proportion of global urban beauty populations living in slums has declined, there has been an increase in the absolute number of people living in these areas. Solution: Find ways to accommodate people where they are.
"Apollo 11 Image library: Landing Site maps/Images". Informal housing in Dhaka, bangladesh. More than.2 billion city dwellers one of every three people living in urban areas lack access to affordable and essay secure housing. This housing gap is a major drag on the economy and the environment. The impact is severe in Asia and Africa, where.25 billion people are expected to be added to urban populations between now and 2050. If business continues as usual, slums will grow across the developing world, exacerbating inequality and threatening cities traditional role as drivers of economic growth. The latest working paper of wris flagship World Resources Report (WRR), towards a more Equal City, draws on the knowledge of dozens of urban experts to examine whether meeting the needs of the urban underserved can improve the economy and environment. Housing is often seen as falling into discrete categories such as public or private, formal or informal, individual or collective.
Retrieved "Cosmonaut Alexei leonov testing out his first Fisher Space pen back in 1968". Retrieved October 4, 2013. "Just the faq ma'am". Archived from the original on October 4, 2013. And Today: mir cosmonauts Use fisher Space pens For Their Writing needs". Archived from the original. Curtin, ciara (December 20, 2006). "Fact or Fiction?: nasa spent Millions to develop a pen that would Write in Space, whereas the soviet Cosmonauts Used a pencil". Duque, pedro (October 23, 2003).
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Felt-tip pens were used by nasa astronauts in the Apollo missions. However, wick-based instruments are designed around low viscosity, and thus operating temperature and pressure. Writing instruments specifically intended for space writing edit The fisher Space pen is a gas-charged ball point pen that is rugged and works in a wider variety of conditions, such as zero gravity, vacuum and extreme temperatures. Its thixotropic ink personal and vent-free cartridge release no significant vapor at common temperatures and low pressures. The ink is forced out by compressed nitrogen at a pressure of nearly 35 psi (240 kpa and it functions at altitudes up to 12,500 feet (3800 m) and at temperatures from 30 to 250 F (35 to 120 C).
However, it is more expensive than the aforementioned alternatives. It has been used by both nasa and soviet/Russian astronauts on Apollo, shuttle, mir, 6 and iss missions. References edit "Is it true that nasa spent thousands of dollars developing a space pen, whereas the russians just took a pencil?". Retrieved 2 november 2012. "The fisher Space pen". Steve garber, nasa history web Curator.
However, wood, graphite, and rubber (in the eraser ) are all combustible and create dust. Graphite, in particular, both burns and produces dust that conducts electricity. The mechanical pencil has been used by nasa starting in the 1960s Gemini program. It can be made to be as wide as the width of astronauts' gloves, yet maintain its light weight. There are no wooden components which might catch fire and create dust.
However, the pencil lead still creates graphite dust that conducts electricity. Grease pencils on plastic slates were used by the soviet space program as an early substitute for wood pencils. It is simple with no moving parts. The paper shroud is peeled back when needed. The disadvantage is that the paper wrapper has to be disposed. Writing done with the grease pencil is also not as durable as ink on paper. Ballpoint pens have been used by soviet and then Russian space programs as a substitute for grease pencils as well as nasa and esa. The pens are cheap, use paper (which is easily available and writing done using pen is more permanent than that done with graphite pencils and grease pencils, which makes the ball point pen more suitable for log books and scientific note books. However, the ink is indelible, and depending on composition is subject to outgassing and temperature variations.
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As air pressure falls, temperatures can swing more dramatically. Many the early manned missions operated at below standard pressure, to decrease the stresses (and thus, mass) of their capsules. Many did not have separate airlocks, instead exposing the entire cabin dissertation to hard vacuum at times. Low pressures also exacerbate contamination issues, as substances acceptable at standard conditions may begin outgassing at lower pressures or higher temperatures. While the soyuz spacecraft had.7 psi (101 kPa) design pressure, and could use its orbital module as an airlock, the orbital module would be deleted for planned lunar missions. In any case, a pen which was insensitive to pressure and temperature would eliminate the issue (including accidental depressurizations provide a margin, and allow the ability to record during extravehicular activities. Pre-existing writing instruments edit The wood pencil has been used for writing by nasa and soviet space programs from the start. It is simple with no moving parts, except for the sharpener.
Quality assurance records document individual parts, and instances of procedures, for deviances. Low production and flight rates generally result in high variance; most spacecraft designs (to say nothing of individual spacecraft) fly so infrequently that they are considered experimental aircraft. When combined with essay the stringent weight drivers of orbital and deep-space flight, the quality-control demands are high. Change control records track the evolution of hardware and procedures from their ground testing, initial flights, through necessary corrections and midlife revision and upgrades, and on to retention of engineering knowledge for later programs, and any incident investigations. When the flight also has scientific or engineering science objectives, low-quality data may affect mission success directly. Faced with these requirements, pencils or other non-permanent recordkeeping methods are unsatisfactory. The act of taking permanent, high-integrity documentation itself deters kludges, workarounds, and " go fever ". The Apollo 1 investigation uncovered procedural and workmanship deficiencies in multiple areas, up to procedures on the pad. Pressure and temperature edit At sea level, temperature is moderated by the thick atmosphere.
protective gear, but both ground and flight crews are more comfortable and more productive " in shirtsleeves ". Fisher of Fisher Pen Company recounts that pencils were 'too dangerous to use in space'. 4, even before the, apollo 1 fire, the, cM crew cabin was reviewed for hazardous materials such as paper, velcro, and even low-temperature plastics. A directive was issued but poorly enforced. When combined with high oxygen content, the Apollo 1 cabin burned within seconds, killing all three crew. Anatoly solovyev flew with Space pens starting in the '80s and states "pencil lead d is not good in space capsule; very dangerous to have metal lead particles in zero gravity". 5, mission assurance and quality records edit, main article: Mission assurance see also: Life-critical system and System engineering Strict documentation requirements accompany anything as complex as a large-scale aerospace demonstration, let alone a manned spaceflight.
As with submarines before them, space capsules are closed environments, subject to strict contamination requirements. Incoming material is screened for mission threats. Any shedding, including wood, graphite, dissertation and ink vapors and droplets, may become a risk. In the case of a manned capsule, the much smaller recirculating volume, combined with microgravity and an even greater difficulty of resupply, make these requirements even more critical. Release of wood shavings, graphite dust, broken graphite tips, and ink compounds are a dangerous flight hazard. Lack of gravity makes objects drift, even with air filtration. Any conductive material is a threat to electronics, including the electromechanical switches in use during early manned space programs.
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Notes on a map written with a felt-tip pen. Michael Collins while in orbit around the moon. Several instruments have been used to write in outer space, including different types of pencils and pens. Some of them have been unmodified versions of conventional writing instruments; others have been invented specifically to counter the problems with writing in space conditions. A common urban legend states that, faced with the fact that ball-point pens would not write in zero-gravity, nasa wallpaper spent a large amount of money to develop a pen that would write in the conditions experienced during spaceflight (the result purportedly being the fisher Space. The fisher Space pen was actually developed independently in a private organization in the 1960s. 1 2 3, contents, mission requirements edit, space versus ground recordkeeping presents several serious issues: Contamination control edit, main article: Contamination control, see also: Apollo.