Operation of the UK Desert Fireball Network

陨石是我们所能获得的最有科学价值的岩石之一，但我们对它们的来源几乎没有限制。由于没有空间背景，解释它们所包含的早期太阳系过程的记录变得极其困难。人们试图通过获得单个陨石坠落的轨道来提供这种背景（使我们能够追踪样本回到它的起源）。这可以通过有组织的火球观测站网络来完成（设计用于拍摄火球，计算轨道，三角测量坠落位置和回收陨石），或者通过偶然的观察和回收。但经过几十年的工作，只有少数有轨道的陨石被发现。问题不在于陨石坠落的数量——仅加拿大陨石观测和恢复项目就观测到50多起陨石坠落事件。问题是地点。陨石是一种黑色的小岩石，在以前的网络所处的植被区很难找到。事实上，在地球表面上，很少有地方可以进行实地搜索，并有实际的成功机会。虽然这是一个重大问题，但它有一个相对简单的解决方案：在已知适合回收陨石的地方建立一个网络。到2007年12月，我已经在澳大利亚沙漠中完成了一个由四个火球观测站组成的试验网络的建设，以证明这个概念。我的团队在2008年10月进行了第一次搜索。在搜索的第一天，我们在预测坠落位置100米内找到了陨石。描述这项工作的论文发表在2009年9月的《科学》杂志上，引起了媒体的极大兴趣，包括在线新闻媒体上的70多篇文章。我们的近期目标是寻求资金，使我们能够建立一个由16个观测站组成的完整的沙漠火球网络，在澳大利亚100万平方公里的范围内探测火球，每年观测10-15次坠落。这个观测站的数量和之前的网络差不多，探测区域也差不多。不同之处在于，在澳大利亚沙漠中放置一个网络将使我的团队能够恢复陨石。有了这种网络，一年之内，我们将运送到轨道上的陨石比200年观测中发现的还要多。在3-4年的时间里，我们将有一个统计上庞大的轨道陨石数据集——这样的数据集不仅会彻底改变这个领域，它的影响将远远超出这个领域。教科书将被重写。通过轨道和反射光谱的相似性将陨石与特定的近地小行星联系起来，将有效地为我们提供这些物体的样本返回任务，但不需要航天器。此外，我们的计算表明，有观测和恢复彗星陨石的真正潜力-在行星科学样本分析方面真正的“圣杯”。星尘号（2.12亿美元）、深度撞击号（3.3亿美元）和罗塞塔号（约9.8亿美元）太空任务证明了彗星样本作为早期太阳系过程的见证人的价值。然而，在寻求资金以显著扩展系统的同时，我们需要保持试验网络的持续运行。这就是本提案的目的。维护当前的网络运营，开发数字系统，组织现场工作需要一个全职的PDRA。我们目前的模拟系统每年观测到约2-3次下降：我们也在申请现场工作资金来覆盖这些搜索。额外的复苏将支持扩大该体系的理由。

Meteorites are amongst the most scientifically valuable rocks available to us, but we have virtually no constraint on where they come from. With no spatial context, interpreting the record of early Solar System processes that they contain becomes extremely difficult. Attempts have been made to provide that context, by getting orbits for individual meteorite falls (allowing us to track a sample back to its origin). This can be accomplished either by organised networks of fireball observatories (designed to photograph fireballs, calculate orbits, triangulate fall positions, and recover meteorites), or through chance observation and recovery. But after decades of work only a handful of meteorites with orbits have been recovered. The problem was not numbers of meteorite falls - the Canadian Meteorite Observation and Recovery Project alone observed over 50 meteorite-dropping events. The problem was location. Meteorites are small dark rocks, which are difficult to find in the vegetated areas where previous networks were sited. In fact, there are relatively few places on the Earth's surface where field searches can be mounted with a realistic chance of success. Although this is a significant problem, it has a relatively simple solution: construct a network in a place known to be suitable for recovering meteorites. By December 2007 I had completed construction of a trial network of four fireball observatories in the Australian desert to prove the concept. My team's first search was conducted in October 2008. We recovered the meteorite within 100m of the predicted fall position, on the first day of the search. The paper describing this work appeared in Science in September 2009 and generated substantial media interest, including over 70 articles in online news outlets. Our near-term goal is to pursue funding that would allow us to build a full Desert Fireball Network of ~16 observatories, detecting fireballs over ~1 million km2 of Australia and observing 10-15 falls per year. This is a similar number of observatories to previous networks, and a similar detecting area. The difference here is that putting a network in the Australian desert will allow my team to recover the meteorites. In a single year with this type of network we would deliver more meteorites with orbits than have been recovered in 200 years of observations. In a 3-4 year period we would have a statistically large dataset of meteorites with orbits - a dataset like that would not only revolutionise this field, it would have repercussions far beyond it. Textbooks would be re-written. Linking meteorites to specific near-Earth asteroids through similarities in orbits and reflectance spectra would effectively provide us with sample-return missions to those objects, but without the need for spacecraft. In addition, our calculations show that there is the real potential to observe and recover a cometary meteorite - a true 'Holy Grail' in terms of planetary science sample analysis. The Stardust (US$212 million), Deep Impact (US$330 million), and Rosetta (~US$980 million) space missions are testimony to the value placed on cometary samples as witnesses of early Solar System processes. However, while pursuing funding to significantly expand the system we need to maintain the continuous operation of our trial network. That is the purpose of this proposal. Maintaining current network operations, developing a digital system, and organising fieldwork requires a full-time PDRA. Our current analogue system is observing ~2-3 falls per year: we are also requesting fieldwork funding to cover those searches. Additional recoveries will bolster the case for expanding the system.