Science from the Extended Mission of the Phoenix Mars Lander

来自凤凰火星登陆器扩展任务的科学

• 批准号: ST/G008485/1
• 负责人: William Pike
• 金额: $ 12.33万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FG008485%2F1
• 关键词: Science; Extended; Mission; Phoenix; Mars

NASA's Phoenix Lander landed on 25-May-2008 in the polar environment of Mars at 68 degrees north, and has taken a close-up look at Mars' surface. The nominal mission was set to last about 3 months, but the mission is still going and has been extended. It will probably keep going until Martian winter closes in, in early 2009. Our work will capitalize on the results to date and support the extended mission operations. Phoenix has a robotic arm, which digs into the ground, and has found ice lying just 5-10 cm below the surface. It has also scooped up samples for analysis and measured the local climate with weather sensors. The overall purpose is to look for clues about where the ice came from, what the soil is made of, and whether microbes might have lived in Mars' early history. Our contribution to the mission will help understand Mars in three ways. Firstly, we will analyze microscopic pictures of the soil particles and use this knowledge to suggest where the lander should scoop up further samples in its extended mission so that we can learn more. We will examine these pictures to determine whether the soil was once deposited from sediments in a lake or sea, carried there by the wind, thrown up by asteroid impact, or came from the erosion and break down of volcanic rocks. Secondly, Phoenix has an experiment where soil scooped up by the robotic arm is mixed with water. Salts in the soil dissolve and probes measure the type of salts, for example whether sodium chloride is present, the salt people use on food. So far, the experiment has discovered that the soil is slightly alkaline, very like that of seawater, and contains components such as magnesium, potassium, and sodium. By analyzing the data further and considering it in detail, we hope to determine whether the salts on Mars were left behind when water dried up or whether the salts came from more recent chemical reactions in the atmosphere and soil. Thirdly, when the Phoenix spacecraft fell to the surface of Mars from space it was slowed down by friction with the air. The rate that the lander decelerated depended on the air density and temperature. We have used the deceleration measurements for a preliminary calculation of how the air density and temperature changed with height. We found that the atmosphere below about 60 km height is unusually warm compared to predictions from the sort of computer models that are similar to those that predict weather on the Earth. We will do more detailed analysis to understand this discrepancy and learn information about the climate, for example, whether there were clouds present during landing or whether the air held lots of dust. We also hope to learn if the unusual atmosphere explains why Phoenix overshot its intended landing site. The microscopy station on Phoenix, that forms a large chunk of our research, consists of an optical microscope that takes colour and ultraviolet pictures and a very-high-resolution microscope called an atomic-force microscope, or AFM. The AFM can image the surfaces of particles smaller than the width of a human hair. These surfaces give us clues about how particles break down and some suggest the decay of volcanic minerals into clays. We plan to do some lab experiments to see if we can replicate on Earth some features seen on Mars. Our research is a great opportunity for a UK contribution to a high profile international Mars mission at modest cost. This research will therefore help to build up the UK's experience of landing on Mars and continue to bring Mars exploration to the UK public.

美国宇航局的凤凰号着陆器于2008年5月25日在火星北纬68度的极地环境中着陆，对火星表面进行了近距离观察。名义上的任务原定持续约 3 个月，但任务仍在继续，并已延长。它可能会持续到 2009 年初火星冬季结束。我们的工作将利用迄今为止的成果并支持扩展的任务操作。 Phoenix 有一个机械臂，可以深入地下，并在地表以下 5 至 10 厘米处发现了冰。它还采集了样本进行分析，并用天气传感器测量了当地的气候。总体目的是寻找有关冰从何而来、土壤由什么构成以及微生物是否可能生活在火星早期历史中的线索。我们对这次任务的贡献将从三个方面帮助了解火星。首先，我们将分析土壤颗粒的显微图片，并利用这些知识来建议着陆器在其扩展任务中应在何处采集更多样本，以便我们了解更多信息。我们将检查这些照片，以确定土壤是否曾经是由湖泊或海洋中的沉积物沉积而成、被风吹到那里、因小行星撞击而扬起、还是来自火山岩的侵蚀和分解。其次，菲尼克斯有一个实验，将机械臂铲起的土壤与水混合。土壤中的盐会溶解，探针会测量盐的类型，例如是否存在氯化钠（人们在食物中使用的盐）。到目前为止，实验发现，土壤呈微碱性，很像海水，含有镁、钾、钠等成分。通过进一步分析数据并详细考虑，我们希望确定火星上的盐是水干涸时留下的，还是来自大气和土壤中最近的化学反应。第三，当凤凰号飞船从太空坠落到火星表面时，它因与空气的摩擦而减慢了速度。着陆器减速的速度取决于空气密度和温度。我们使用减速度测量值来初步计算空气密度和温度如何随高度变化。我们发现，与类似地球天气预测的计算机模型的预测相比，大约 60 公里高度以下的大气异常温暖。我们将进行更详细的分析，以了解这种差异并了解有关气候的信息，例如，着陆时是否有云，或者空气中是否含有大量灰尘。我们还希望了解这种不寻常的气氛是否可以解释为什么凤凰号超出了其预定的着陆地点。凤凰城的显微镜站构成了我们研究的很大一部分，它由一个可拍摄彩色和紫外线照片的光学显微镜和一个称为原子力显微镜（AFM）的超高分辨率显微镜组成。 AFM 可以对小于人类头发宽度的颗粒表面进行成像。这些表面为我们提供了有关颗粒如何分解的线索，其中一些表明火山矿物腐烂成粘土。我们计划做一些实验室实验，看看是否可以在地球上复制火星上看到的一些特征。我们的研究是英国以适度的成本为备受瞩目的国际火星任务做出贡献的绝佳机会。因此，这项研究将有助于积累英国登陆火星的经验，并继续将火星探索带给英国公众。

项目成果

Dual wavelength optical metrology using ptychography

• DOI: 10.1088/2040-8978/15/3/035702
• 发表时间: 2013-01
• 期刊: Journal of Optics
• 影响因子: 2.1
• 作者: Daniel Claus;David Robinson;D. Chetwynd;Y. Shuo;William T. Pike;José J De J Toriz Garcia-José-J-De-J-Toriz-Garcia-2253794777;J. M. Rodenbur

Search for ultraviolet luminescence of soil particles at the Phoenix landing site, Mars

在凤凰号火星着陆点寻找土壤颗粒的紫外线发光

• DOI: 10.1016/j.pss.2012.05.002
• 发表时间: 2012
• 期刊: Planetary and Space Science
• 影响因子: 2.4
• 作者: Goetz W

Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties

• DOI: 10.1029/2009je003437
• 发表时间: 2010-08-04
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
• 影响因子: 4.8
• 作者: Goetz, W.;Pike, W. T.;Tanner, R.
• 通讯作者: Tanner, R.

Penetrators for in situ subsurface investigations of Europa

• DOI: 10.1016/j.asr.2010.06.026
• 发表时间: 2011-08
• 期刊: Advances in Space Research
• 影响因子: 2.6
• 作者: R. Gowen;Alan Smith;A. Fortes;S. Barber;P. Brown;P. Church;G. Collinson;A. Coates;G. Collins;I. Crawford;V. Dehant;J. Chela-Flores;A. Griffiths;P. Grindrod;L. Gurvits;A. Hagermann;H. Hussmann;R. Jaumann;A. Jones;K. Joy;Ö. Karatekin;K. Miljković;E. Palomba;W. Pike;O. Prieto-Ballesteros;F. Raulin;M. Sephton;S. Sheridan;M. Sims;M. Storrie-Lombardi;R. Ambrosi;J. Fielding;G. Fraser;Yang Gao;G. Jones;G. Kargl;W. Karl;A. Macagnano;A. Mukherjee;J. Muller;A. Phipps;D. Pullan;L. Richter;F. Sohl;J. Snape;J. Sykes;N. Wells

Microscopy capabilities of the Microscopy, Electrochemistry, and Conductivity Analyzer

• DOI: 10.1029/2008je003077
• 发表时间: 2008-10-31
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
• 影响因子: 4.8
• 作者: Hecht, M. H.;Marshall, J.;Woida, P. M.
• 通讯作者: Woida, P. M.