Draft:Solar mirrors in the stratosphere
Several groups think large hot air balloons can fly long term in the stratosphere, using solar energy to heat the air that provides the lift. Besides transponders that serve cellphones and provide some of the same purposes as communications satellites; steerable mirrors can beam sunlight through holes in the clouds to existing solar energy sites.
Space power application
"Solar dynamic" energy systems have been proposed for various spacecraft applications, including solar power satellites, where a reflector focuses sunlight on to a heat engine such as the Brayton cycle type.
Space reflectors for night illumination
Another advanced space concept proposal is the notion of Space Reflectors which reflect sunlight on to small spots on the night side of the Earth to provide night time illumination. An early proponent of this concept was Dr. Krafft Arnold Ehricke, who wrote about systems called "Lunetta", "Soletta", "Biosoletta" and "Powersoletta".
A preliminary series of experiments called Znamya ("Banner", a space mirror) was performed by Russia, using solar sail prototypes that had been re-purposed as mirrors. Znamya-1 was a ground test. Znamya-2 was launched aboard the Progress M-15 resupply mission to the Mir space station on 27 October 1992. After undocked from Mir, the Progress deployed the reflector. This mission was successful in that the mirror deployed, although it did not illuminate the Earth. The next flight Znamya-2.5 failed. Znamya-3 never flew.
Balloons for technology
Balloons provide a long-duration platform to study any atmosphere, the universe, the Sun, and the near-Earth and space environment above as much as 99.7 % of the Earth's atmosphere. Unlike a rocket where data are collected during a brief few minutes, balloons are able to stay aloft for much longer. Balloons for technology offer a low-cost, quick-response method for conducting scientific investigations. They are mobile, meaning they can be launched where the scientist needs to conduct the experiment, in as little as six months.
The Ultra Long Duration Balloon (ULDB) Project is developing new composite materials and a new balloon design, a standard gondola including power, global telemetry/command and an altitude control system. The ULDB is seeking to improve mission control and operations and the integration of scientific instruments. It is the potential for longer duration flights that has been the driver for the resurgence of interest in balloons by the scientific community. In recent years, the manned global ballooning attempts have called attention to the difficulty of achieving “longer”.
"High altitude balloons are an inexpensive means of getting payloads to the brink of space [The first test shown in the image on the left] was launched from McMurdo Station in Antarctica. The balloon reached a float altitude of more than 111,000 feet and maintained it for the entire 11 days of flight. [...] The flight tested the durability and functionality of the scientific balloon’s novel globe-shaped design and the unique lightweight and thin polyethylene film. It launched on December 28, 2008 and returned on January 8, 2009."
"The University of Hawaii Manoa’s Antarctic Impulsive Transient Antenna launched December 21, 2008, and is still aloft. Its radio telescope is searching for indirect evidence of extremely high-energy neutrino particles possibly coming from outside our Milky Way galaxy."
- Mason, Lee S.; Richard K. Shaltens; James L. Dolce; Robert L. Cataldo (January 2002). "Status of Brayton Cycle Power Conversion Development at NASA GRC" (PDF). NASA Glenn Research Center. Retrieved 2007-02-25.
- Ehricke, Krafft Arnold (September 1, 1977). "Power Soletta: An industrial sun for Europe - Possibilities for an economically feasible supply with solar energy,". Astronautik (Berlin, West Germany: Hermann-Oberth-Gesellschaft) 14 (3): 85–87.
- Ehricke, Krafft Arnold (January 1978). "The Extraterrestrial Imperative". Air University Review (United States Air Force) XXIX (2). http://www.airpower.maxwell.af.mil/airchronicles/aureview/1978/jan-feb/ehricke.html. Retrieved 2007-02-25.
- McDowell, Jonathan (1993-02-10). Jonathan's Space Report - No 143 - Mir, In: Jonathan's Space Report. Jonathan McDowell. Retrieved 2007-02-25.
- Wade, Mark (n.d.). Mir EO-12, In: Encyclopedia Astronautica. Mark Wade. Retrieved 2007-02-25.
- BBC, Sci/Tech: Znamya falls to Earth, February 4, 1999 (accessed 2011-08-24)
- Wade, Mark (n.d.). Mir News 453: Znamya 2.5. Encyclopedia Astronautica. Mark Wade. Retrieved 2007-02-25.
- Nancy Atkinson (9 January 2009). NASA Tests New Super-Thin High Altitude Balloon. Universe Today. Retrieved 2017-08-10.
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