Tuesday, December 7, 2010

UNIVERSE-NASA ejects Nanosatellite from Microsatellite in Space

         The term "nanosatellite" or "nanosat" is usually applied to the name of an artificial satellite with a wet mass between 1 and 10 kg (2.2 and 22 lb). Again designs and proposed designs of these types usually have multiple nanosatellites working together or in formation (sometimes the term "swarm" is applied). Some designs require a larger "mother" satellite for communication with ground controllers or for launching and docking with nanosatellites.
          Nanosatellites, also called "nanosats", are a relatively recent term used to describe artificial satellites with a mass between 1 and 10 kg (2.2–22 lb). Larger satellites are often called microsatellites, while smaller satellites are called picosatellites. The term "nanosatellite" appears to have been introduced by NASA some time around 2004. It is still in the process of adoption, as many satellites of this size are simply called "small satellites."

                     The idea of a nanosatellite has absolutely nothing to do withnanotechnology, a term that refers the precise engineering of materials on atomic and molecular scales. From a nanoscale perspective, a 5-kg satellite looks like Mt. Everest. Nanosatellites are appealing because their small size makes them affordable and opens up the potential for a swarm of the satellites. They can piggyback on larger launches, avoiding the need for a dedicated launch. From a military perspective, a nanosatellite may be useful for the redundancy it could offer. Its small size might also help it avoid detection.
One of the earliest uses of the term "nanosatellite" was by NASA in reference to their volleyball-sized Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam) satellites, which weigh about ten pounds. The purpose of this nanosatellite, which is still in testing, is to be launched from a larger parent craft and used for the purpose of expecting the outside of a larger vehicle without necessitating a risky spacewalk. The value of such safety systems is acutely obvious, as the Space Shuttle Columbia broke up during reentry in February 2003, leading to the death of all seven crew members. This accident may have been avoided if the shuttle's heat shield was examined more closely before reentry.
          As crucial electronics components such as cameras become more miniaturized, nanosatellites become possible. There is limited research in the area of nanosatellites today, as most space companies and universities focus on larger satellites, but there are signs that many are recognizing the potential of nanosatellites and conducting innovative research into them.

         On Dec. 6 at 1:31 a.m. EST, NASA for the first time successfully ejected a nanosatellite from a free-flying microsatellite. NanoSail-D ejected from the Fast, Affordable, Science and Technology Satellite, FASTSAT, demonstrating the capability to deploy a small cubesat payload from an autonomous microsatellite in space. 
           Nanosatellites or cubesats are typically launched and deployed from a mechanism called a Poly-PicoSatellite Orbital Deployer (P-POD) mounted directly on a launch vehicle. This is the first time NASA has mounted a P-POD on a microsatellite to eject a cubesat. 

FASTSAT, equipped with six science and technology demonstration payloads, including NanoSail-D, launched Friday, Nov. 19 at 8:25 p.m. EST from Kodiak Island, Alaska. During launch, the NanoSail-D flight unit, about the size of a loaf of bread, was stowed inside FASTSAT in a P-POD. 
            "The successful ejection of NanoSail-D demonstrates the operational capability of FASTSAT as a cost-effective independent means of placing cubesat payloads into orbit safely," said Mark Boudreaux, FASTSAT project manager at the Marshall Space Flight Center in Huntsville, Ala. "With this first step behind us, we have demonstrated we can launch a number of different types of payloads using this common deployment system from an autonomous microsatellite like FASTSAT." 
                  "NanoSail D has multiple enabling technology demonstration objectives for this flight," said Joe Casas, FASTSAT project scientist at Marshall. Casas said when the NanoSail-D sail is deployed it will use its large sail made of thin polymer material, a material much thinner than a single human hair, to significantly decrease the time to de-orbit the small satellite without the use of propellants as most traditional satellites use. 

The NanoSail-D flight results will help to mature this technology so it could be used on future large spacecraft missions to aid in de-orbiting space debris created by decommissioned satellites without using valuable mission propellants. 
                    "This is a great step for our solar sail team with the successful ejection of the NanoSail-D satellite from FASTSAT," said Dean Alhorn, NanoSail-D principal investigator and aerospace engineer at the Marshall Center. "We had to carefully plan and calculate the ejection time, so we'd be lined up over the United States and our ground controllers to execute the next phase of the mission." 
       After ejection, a timer within NanoSail-D will begin a three day countdown as the satellite orbits the Earth. Once the timer reaches zero, four booms will quickly deploy and the NanoSail-D sail will start to unfold to a 100 square foot polymer sail. Within five seconds the sail fully unfurls. 

If the deployment is successful, NanoSail-D will stay in low-Earth orbit between 70 and 120 days, depending on atmospheric conditions. NanoSail-D is designed to demonstrate deployment of a compact solar sail boom system that could lead to further development of this alternative solar sail propulsion technology and FASTSAT’s ability to eject a nanosatellite from a microsatellite -- while avoiding re-contact with the FASTSAT satellite bus.

NanoSail-D was designed and built by engineers in Huntsville and managed at the Marshall Center with technical and hardware support from NASA's Ames Research Center in Moffett Field, Calif. This experiment is a combined effort between the Space and Missile Defense Command, Von Braun Center for Science and Innovation, both located in Huntsville, Ala. and NASA. 

                  FASTSAT launched on the STP-S26 mission -- a joint activity between NASA and the U.S. Department of Defense Space Test Program. The satellite was designed, developed and tested at the Marshall Center in partnership with the Von Braun Center for Science & Innovation and Dynetics Inc. of Huntsville. Dynetics provided key engineering, manufacturing and ground operations support for the new microsatellite. Thirteen Huntsville-area firms, as well as the University of Alabama in Huntsville, also were part of the project team. 
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