MAVEN Mission to Investigate How Sun Steals Martian Atmosphere

探究太阳“偷窃”火星大气之谜----MAVEN 卫星
http://www.nasa.gov/mission_pages/maven/news/confirmation.html
On Mars, hydrogen escapes faster because it is lighter than deuterium. Since the lighter version escapes more often, over time, the martian atmosphere has less and less hydrogen compared to the amount of deuterium remaining. The martian atmosphere therefore becomes richer and richer in deuterium.
在火星上，由于比氘轻，氢更易逃脱。因为逃脱的很频繁，相对于留在火星大气中的氘，氢变得越来越少，氘也因此变得越来越多。

The MAVEN team will measure the amount of hydrogen compared to the amount of deuterium in Mars' upper atmosphere, which is the planet's present-day hydrogen to deuterium (H/D) ratio. They will compare it to the ratio Mars had when it was young -- the original H/D ratio. The original ratio is estimated from observations of the H/D ratio in comets and asteroids, which are believed to be pristine, "fossil" remnants of our solar system's formation.
MAVEN卫星的团队将检测火星大气上层的氢氘比（目前比值），并与原始火星的氢氘比作比较。原始的比值来源于彗星和小行星（原始的，太阳系形成过程中残存的“化石”。

Comparing the present and original H/D ratios will allow the team to calculate how much hydrogen, and therefore water, has been lost over Mars' lifetime. For example, if the team discovers the martian atmosphere is ten times richer in deuterium today, the planet's original quantity of water must have been at least ten times greater than that seen today.
通过比较现在与原始的H/D比值，可以让该团队计算出到底有多少氢以及水在火星的一生中丢失。举个例子，如果发现在氘的含量上，现在是过去的10倍，则火星原始水含量至少比现在水含量多10倍。

MAVEN will also help determine how much martian atmosphere has been lost over time by measuring the isotope ratios of other elements in the air, such as nitrogen, oxygen, and carbon.
MAVEN卫星将通过检测碳、氧、氮等其他元素的同位素在空气中的比值，来帮助判断有多少火星大气逃逸。

MAVEN is scheduled for launch between November 18 and December 7, 2013. If it is launched November 18, it will arrive at Mars on September 16, 2014 for its year-long mission.
MAVEN卫星计划在2013年11.18～12.7号发射。如果在11.18日发射，将在2014.9.16日到达火星，开始它的常年任务。

MAVEN is part of NASA's Mars Scout program, funded by NASA Headquarters in Washington, DC. The University of Colorado will coordinate the science team and science operations. NASA Goddard will manage the project and provide mission systems engineering, mission design, and safety and mission assurance. NASA's Jet Propulsion Laboratory, Pasadena, Calif., will navigate the spacecraft, provide the Deep Space Network, and an Electra telecommunications relay package. Instruments on the spacecraft will be provided by the University of California, Berkeley, the University of Colorado, Boulder, and NASA Goddard, with the Centre d’Etude Spatiale des Rayonnements, Toulouse, France, providing the sensor for one instrument. Lockheed Martin Corp., Bethesda, Md., will develop the spacecraft, conduct assembly, test and launch operations, and provide mission operations at their Littleton, Colorado facility.
MAVEN卫星是NASA火星探测计划的一部分，由NASA华盛顿总部提供资金支持。科罗拉多大学将协调科学工作组与实验。NASA Goddard 将组织至此项目并提供任务系统工程、设计、安全以及保证。NASA喷气动力实验室为卫星导航，提供深空网络及中继信息传递服务。加州伯克利, 科罗拉多, Boulder以及 NASA Goddard将提供卫星的仪器设备。the Centre d’Etude Spatiale des Rayonnements, Toulouse, France将提供卫星一仪器的传感元件。Lockheed Martin Corp., Bethesda, Md.,将开发航天器，进行装配，检测发射操作，并提供科罗拉多发射的操作命令。

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