A look back, part II: The drilling campaign of the Curiosity rover during the Mars Science Laboratory's second and third Martian years

The Mars Science Laboratory (MSL) rover, Curiosity, completed its second Martian year, 1337 sols (1374 Earth days), of operation on May 11, 2016, and its third Martian year, 2006 sols (2061 Earth days), of operation on March 28, 2018. During this time the rover successfully drilled twelve full depth drill holes into the Martian surface and analyzed the recovered material using onboard instruments, giving us new insights into the potential habitability and geologic diversity of ancient Mars. During the second Martian year, four holes were sunk into the mudstones of the Murray formation: 'Confidence Hills' (Sol 759), 'Mojave 2' (Sol 882), 'Telegraph Peak' (908) & 'Buckskin' (Sol 1060); while four more holes were sunk into the sandstones of the Stimson formation: 'Big Sky' (Sol 1119), 'Greenhorn' (Sol 1137), 'Lubango' (Sol 1320) & 'Okoruso' (Sol 1332). During the third Martian year, four additional holes were sunk into the Murray formation: 'Oudam' (Sol 1361), 'Marimba' (Sol 1422), 'Quela' (Sol 1464) & 'Sebina' (Sol 1495). In this paper, we will give a brief overview of the rover sampling hardware and nominal drilling protocols, followed by a discussion of how these protocols were refined and altered early during the course of Curiosity's second year on Mars. In addition, we will describe the 'Bonanza King' (Sol 724) drill campaign, the mission's first 'successful failure', and how it influenced these changes. We will also briefly discuss the events leading up to the drill feed fault on Sol 1536, which resulted in suspension of all drill activities for the remainder of the third Martian year. Finally, we will present scientific highlights obtained from each drill site utilizing MSL's onboard instrumentation (SAM & CheMin), results enabled by the drill’s ability to excavate sample at depth and transfer it to these instruments.

火星科学实验室（Mars Science Laboratory, MSL）的“好奇号”（Curiosity）火星车于2016年5月11日完成了第2个火星年的探测运行，累计时长1337个火星日（sol，合1374个地球日）；并于2018年3月28日完成第3个火星年的探测运行，累计时长2006个火星日（合2061个地球日）。在此期间，该火星车成功在火星表面钻取12个全深度钻孔，并利用搭载的科学仪器对获取的样品进行分析，为我们深入解析古代火星潜在宜居性与地质多样性提供了全新认知。
在第2个火星年期间，科研人员在默里组（Murray formation）的泥岩中钻取了4个钻孔：“信心山”（Confidence Hills，第759个火星日（Sol））、“莫哈韦2号”（Mojave 2，第882个火星日（Sol））、“电报峰”（Telegraph Peak，第908个火星日）与“鹿皮”（Buckskin，第1060个火星日（Sol））；同时在斯廷森组（Stimson formation）的砂岩中钻取了另外4个钻孔：“大天空”（Big Sky，第1119个火星日（Sol））、“绿角”（Greenhorn，第1137个火星日（Sol））、“卢班戈”（Lubango，第1320个火星日（Sol））与“奥科鲁索”（Okoruso，第1332个火星日（Sol））。
在第3个火星年期间，科研人员又在默里组（Murray formation）的岩层中钻取了4个钻孔：“乌达姆”（Oudam，第1361个火星日（Sol））、“马林巴”（Marimba，第1422个火星日（Sol））、“奎拉”（Quela，第1464个火星日（Sol））与“塞比纳”（Sebina，第1495个火星日（Sol））。
本文将首先对该火星车的采样硬件与标准化钻探规程进行简要概述，随后探讨在“好奇号”登陆火星的第2年早期，这些钻探流程是如何被优化与调整的。此外，本文将介绍“富矿之王”（Bonanza King，第724个火星日（Sol））的钻探作业——该作业是本次任务的首起“成功的失败”案例，并阐述其如何推动了上述流程的调整。本文还将简要介绍导致第1536个火星日（Sol）出现钻探进给故障的一系列事件，该故障致使整个第3个火星年剩余时段内的所有钻探活动全面暂停。最后，本文将展示利用MSL搭载的科学仪器——火星样品分析仪（Sample Analysis at Mars, SAM）与化学与矿物学分析仪（Chemistry and Mineralogy, CheMin）——从每个钻探位点获取的核心科学成果，这些成果得益于钻探系统能够从地下深处挖掘样品并将其输送至上述仪器的能力。