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Raumfahrt - Mars-Sonde MAVEN bekommt Struktur

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NASA has selected a Mars robotic mission that will provide information about the Red Planet's atmosphere, climate history and potential habitability in greater detail than ever before. 
Called the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, the $485 million mission is scheduled for launch in late 2013. The selection was evaluated to have the best science value and lowest implementation risk from 20 mission investigation proposals submitted in response to a NASA Announcement of Opportunity in August 2006.
"This mission will provide the first direct measurements ever taken to address key scientific questions about Mars' evolution," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. 
Mars once had a denser atmosphere that supported the presence of liquid water on the surface. As part of a dramatic climate change, most of the Martian atmosphere was lost. MAVEN will make definitive scientific measurements of present-day atmospheric loss that will offer clues about the planet's history.
"The loss of Mars' atmosphere has been an ongoing mystery," McCuistion said. "MAVEN will help us solve it."
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In the photo taken on Sept. 8, technicians from Lockheed Martin are inspecting the MAVEN primary structure following its recent completion at the company’s Composites Lab. The primary structure is cube shaped at 7.5 feet x 7.5 feet x 6.5 feet high (2.3 meters x 2.3 meters x 2 meters high). Built out of composite panels comprised of aluminum honeycomb sandwiched between graphite composite face sheets and attached to one another with metal fittings, the entire structure only weighs 275 pounds (125 kilograms). At the center of the structure is the 4.25 feet (1.3 meters) diameter core cylinder that encloses the hydrazine propellant tank and serves as the primary vertical load-bearing structure. The large tank will hold approximately 3,615 pounds (1640 kilograms) of fuel. 
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DENVER,  Sept. 11, 2012 – Lockheed Martin [NYSE: LMT] has begun the assembly, test and launch operations (ATLO) phase for NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. MAVEN is scheduled to launch in November 2013 and will be the first mission devoted to understanding the Martian upper atmosphere.
ATLO represents a critical stage of the program because it is when the spacecraft begins to take form and culminates with its launch. Over the next five months technicians will install the subsystems on the main spacecraft structure, comprising avionics, power, telecomm, mechanisms, thermal systems, and guidance, navigation and control. The propulsion system was installed earlier this year and in mid-August the spacecraft was powered up with flight software for the first time.
During ATLO science instruments are being delivered to Lockheed Martin’s Littleton, Colo. facility for integration with the spacecraft. Once the spacecraft has been fully assembled, it will undergo rigorous environmental testing in early 2013.
“I think it’s very timely that we started assembly of MAVEN during the centennial year of our corporation,” said Guy Beutelschies, MAVEN program manager at Lockheed Martin Space Systems Company. “Helping our customers rise to the challenge of tomorrow and discover new things is inherent to our core values and our team is thrilled to begin this next phase of the MAVEN mission.”
On Sept. 10 the MAVEN project officially received authorization to transition into the next phase of the mission, Phase D, after completing a series of independent reviews which cover not only technical health of the project but also programmatic health (schedule and cost). The key decision meeting was held at NASA Headquarters in Washington and was chaired by NASA's Science Mission Directorate.
MAVEN is a robotic exploration mission with the goal to determine the role that loss of atmospheric gas to space played in changing the Martian climate through time. It will determine how much of the Martian atmosphere has been lost over time by measuring the current rate of escape to space and gathering enough information about the relevant processes to allow extrapolation backward in time.
MAVEN's principal investigator is based at the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics. The university will provide science operations, build instruments, and lead Education/Public Outreach. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the project and is building two of the science instruments for the mission. Lockheed Martin of Littleton, Colo., will build the spacecraft and perform mission operations. The University of California-Berkeley Space Sciences Laboratory is building instruments for the mission. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., provides Program management via the Mars Program Office, as well as navigation support, the Deep Space Network, and the Electra telecommunications relay hardware and operations.
Headquartered in Bethesda, Md., Lockheed Martin is a global security and aerospace company that employs about 120,000 people worldwide and is principally engaged in the research, design, development, manufacture, integration and sustainment of advanced technology systems, products and services. The corporation's net sales for 2011 were $46.5 billion.
Quelle: Lockheed-Martin
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MAVEN will have four primary scientific objectives:
1.     Determine the role that loss of volatiles from the Mars atmosphere to space has played through time
2.     Determine the current state of the upper atmosphere, ionosphere, and interactions with the solar wind
3.     Determine the current rates of escape of neutral gases and ions to space and the processes controlling them
4.     Determine the ratios of stable isotopes that will tell Mars’ history of loss through time
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Foto: Lockheed-Martin
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Mission Timeline
MAVEN is slated to launch at 2:40 PM (EST) on November 18, 2013, for arrival at Mars on September 22, 2014. The first fuel burn will insert the spacecraft into a capture orbit with a period of 35 hours (the time it will take to make one complete orbit around Mars) and an altitude of approximately 590 kilometers. Shortly after Mars orbit insertion, a second fuel burn will place the spacecraft into its 4.5-hour period requirement for acquiring data. Three smaller burns will reduce the periapsis altitude (closest distance) of the spacecraft to approximately 150 kilometers, placing MAVEN within the required corridor and a 75° inclination elliptical science mapping orbit.
MAVEN measurements will be made from this orbit over a period of one Earth year, with five 5-day “deep dips” interspersed to sample the entire upper atmosphere.
Goddard Space Flight Center (GSFC) will lead the mission design and will manage the mission design and navigation for MAVEN. Operational navigation is led by the Jet Propulsion Laboratory (JPL).
This schedule provides thorough coverage of solar conditions, local time, latitude, and crustal magnetic configuration, and ensures that we obtain the measurements necessary to achieve all science objectives.
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