The Design and Engineering of Curiosity

by Emily Lakdawalla

  4Described in detail in Peters et al. (2016)

  5Maurice et al. (2016)

  6Maurice et al. (2016)

  7Ollila et al. (2014)

  8Lanza et al. (2016)

  9Maurice et al. (2016)

  10Roger Wiens, personal communication, email dated March 26, 2016

  11Roger Wiens, personal communication, email dated March, 26, 2016

  12Cousin et al. (2014)

  13Roger Wiens, personal communication, email dated March 26, 2016

  14Francis et al. (2016)

  15Francis et al. (2017)

  16Maurice et al. (2016)

  17Roger Wiens, personal communication, email dated December 17, 2015

  18William Rapin, personal communication, email dated April 5, 2016

  19There is no peer-reviewed publication describing the APXS as there is for most other instruments; there is only an LPSC abstract: Gellert et al. (2009); two other good sources of information on the instrument and its performance on Mars are Gellert et al. (2015) and Campbell et al. (2012)

  20Farley et al. (2014)

  21Dickinson et al. (2012)

  22Perrett et al. (2017)

  23Slavney (2013)

  24Dickinson et al. (2012)

  25Ralf Gellert, personal communication, email dated May 10, 2016

  26Mariek Schmidt, personal communication, email dated April 17, 2017

  27Ashwin Vasavada, personal communication, email dated March 28, 2017

  28Ralf Gellert, personal communication, email dated May 10, 2016

  29Gellert et al. (2015)

  30Ralf Gellert, personal communication, email dated May 10, 2016

  31Berger et al. (2014)

  32Berger et al. (2016)

  33Thompson et al. (2016)

  34Schmidt et al. (2016)

  35Slavney (2013)

  36Ralf Gellert, personal communication, email dated May 10, 2016

  37The main reference for the description of the CheMin instrument is Blake et al. (2012); a useful summary of how it has worked on Mars is in Downs (2015)

  38Vaniman et al. (2014)

  39Léveillé et al. (2015)

  40David Vaniman, personal communication, email dated April 5, 2017

  41David Vaniman, personal communication, email dated March 8, 2017

  42See, for example, Treiman et al. (2016) and Morris R et al (2016)

  43Morris et al. (2016)

  44The SAM instrument description paper is Mahaffy et al. (2012); useful summaries of post-landing performance are in Millan et al. (2016) and Franz et al. (2017)

  45Paul Mahaffy, personal communication, email dated April 8, 2017

  46Webster et al. (2014)

  47Paul Mahaffy, personal communication, email dated April 8, 2017

  48Mahaffy et al. (2013)

  49Charles Malespin, personal communication, email dated April 12, 2017

  50Atreya et al. (2013)

  51ibid.

  52Conrad et al. (2016)

  53Lakdawalla (2013)

  54Charles Malespin, personal communication, email dated April 12, 2017

  Epilogue: Back on Earth

  That Curiosity is still operating on Mars more than 5 years after landing is testament to the dedication and focus of a huge human team that keeps it safe and productive. The science team has over 500 members scattered around the world. Nearly 100 people are “on shift” on any given day of mission operations, including the engineering teams at JPL and the external scientists (Figure 10.1 ). Over the course of its development, launch, cruise, landing, and surface operation, more than 7000 different people from at least 33 of the United States and in 11 other countries have been involved in the mission.

  Figure 10.1. A portion of the Curiosity team at JPL on October 11, 2016, with the testbed rover. JPL-Caltech/Dutch Slager .

  Since landing, numerous members of the engineering and operations teams at JPL have moved on to other projects. Many of the people who were key to development are now working on the mission’s descendant, currently known as Mars 2020, which will reuse the designs of the cruise stage and entry, descent, and landing architecture to deliver a Curiosity-like rover (though with a different science package) to collect samples on Mars for a hypothetical future sample return mission.

  Like most robotic missions sent to Mars, the gargantuan effort summarized in this book has one purpose: science. As of October 2017, the mission counts 250 peer-reviewed publications by team members and 157 by non-team members using mission data. The pace of publication of scientific results appeared slow to outsiders, especially to people accustomed to the rapid work of the Mars Exploration Rovers, but Curiosity’s science has much more in common with NASA’s other flagship exploration missions like Cassini and Galileo than it does with Spirit and Opportunity.

  Curiosity performs long “cruises” from science field site to field site, interspersed with weeks-long periods of intensive data gathering. While at the field site, there is only time to verify data quality. The analytical laboratory instruments actually do most of their work while traversing from site to site. The SAM team, in particular, has to do significant lab work on Earth to understand results from Mars. Initial scientific analysis of data and publication of results happens mostly within instrument teams, so the first papers typically focus on results from one instrument at one site. Comparison across sites and instrument teams takes more time, and synthesizing all of that into coherent geologic history takes longer yet. For all these reasons, publication of papers addressing the geologic history and habitability of each field site may happen years after Curiosity has left it. And it’s only as Curiosity crosses major geologic boundaries that the science team is beginning to get a picture of the evolution of the whole Gale crater system over time. The payoff from the environmental instruments REMS and RAD increases, the longer that they gather data.

  Understanding how the rover and mission work is a necessary prerequisite to understanding the mission’s science results. Those have been the focus of this book. The scientific story of the Curiosity mission – the geologic setting, traverse, field sites, and science results – is beyond the scope of this book. You may read that story in the next book, Curiosity and Its Science Mission: A Mars Rover Goes to Work .

  When this book was submitted for publication in late 2017, the rover had just climbed onto Vera Rubin Ridge, seeing for the first time into the valley beyond. It paused to take a self-portrait on sol 1943 (Figure 10.2 ). The ridge and valley represent new rocks and new history for Curiosity, embodying a 500-member science team, to explore.

  Figure 10.2. Curiosity self-portrait atop Vera Rubin Ridge, sol 1943, or January 23, 2018. Behind the rover is Mount Sharp. Credit: NASA/JPL-Caltech/MSSS .

  Appendix: Curiosity Activity Summary

  Following is a condensed historical summary of the Curiosity mission from sol 0-1648. Columns include: Area: A general descriptor of the mission phase, color coded: drives (white), engineering activities (orange), contact science (blue), scooping (pink), drilling (purple). These are not formally identified; rather, they were categorized by the author.

  Noon UTC: Time UTC corresponding to Curiosity noon LMST for the given sol. Calculated using the Mars equation of time by Joe Knapp.

  Sol: elapsed Martian day of mission.

  RS: Indicates if remote sensing activities were performed with science instruments, where C = ChemCam and M = Mastcam, with lowercase indicating fewer observations and uppercase indicating more. Based on Planetary Data System Geosciences Node records of numbers of data products per sol for these instruments. Intended to provide a qualitative estimate of how intense was the remote sensing activity on a given sol.

  Arm: Contains one-letter codes summarizing most arm activities, organized alphabetically roughly in the order in which they are typically performed at sample sites: A = APXS measurement; B = Brush; C = sCoop; D = mini-Drill; F = Full drill; I = Inspection of pre- and post-sieve sample volume; P = self-Portrait; S = dump pre-Sieve sample;
U = dUmp post-sieve sample; X = CHIMRA cleanout; W = Wheel imaging. Cells for sols during which drill or CHIMRA contain sample are colored in gray. MAHLI activities other than self-portraits or wheel imaging are not included in this column for clarity, because there are too many. Based on rover activities as recorded in spacecraft images, SOWG and Mission Manager reports and Historical Overview notes from the Planetary Data System Geosciences Node; MAHLI Principal Investigator's Notebooks; and APXS team records of activities courtesy Mariek Schmidt and Lucy Thompson.

  Activity summary: includes one-sol drive distance; rover site/drive, change in elevation (in meters) from landing site, and total odometry (in meters) at end of drive; and comments on engineering activities, contact science targets, and other notable events. The column's account of contact science targets is complete, but it is not complete as to mobility or arm faults or runout sols because of a lack of public information. Sols known to have been lost to runouts or anomalies are colored in gray. Same sources as for Arm column.

  Ls: Solar longitude, a proxy for season (0 = autumnal equinox, 90 = winter solstice, 180 = vernal equinox, 270 = summer solstice.) From the "Historical Overview" summaries available at the Planetary Data System Geosciences Node.

  T: Minimum daily temperature from REMS ground temperature sensor, in kelvins. Obvious outliers have been removed, but these data are noisy. Color coded from blue (relatively cold) through white to red (relatively warm). Intended to allow you to tell, at a glance, through cell color, whether the season is warm or cold. Raw data courtesy Mark Lemmon.

  P: Maximum daily pressure from REMS pressure sensor, with same warnings as for temperature data. Color coded from dark green (relatively low pressure) to white (relatively high). Raw data courtesy Mark Lemmon.

  Tau: atmospheric opacity calculated by Mark Lemmon based on Mastcam solar imaging. Where multiple measurements exist for a sol, they have been averaged. Color coded from yellow (clear skies) to smoggy brown (dusty).

  About the Author

  Emily Lakdawalla is Senior Editor and Planetary Evangelist for The Planetary Society. She is an internationally known science communicator who shares her passion for solar system exploration by writing and editing The Planetary Society’s blogs at planetary.​org/​blog , speaking to classrooms, sharing space photos and science explanations on twitter.​com/​elakdawalla , and developing other space science education projects.

  Emily holds a Master of Science degree in planetary geology from Brown University, where she studied tectonics on Venus and was among the first to develop Geographic Information Systems off of Earth. She began writing about space exploration for the public when Cassini arrived at Saturn in 2004, and has since covered the science and operations of robotic missions across the solar system, from MESSENGER at Mercury to Rosetta at 67P/Churyumov-Gerasimenko and New Horizons at Pluto. Emily has been an active supporter of the international community of space image processing enthusiasts as Administrator of the forum UnmannedSpacefli​ght.​com since 2005. She is also a contributing editor to Sky & Telescope magazine.

  Emily has been recognized by the space science community for her work in promoting space exploration to the public. She was awarded the 2011 Jonathan Eberhart Planetary Sciences Journalism Award from the Division for Planetary Sciences of the American Astronomical Society for her blog entry about the Phoebe ring of Saturn. Asteroid 274860 was formally named "Emilylakdawalla" by the International Astronomical Union on July 12, 2014. She received an honorary doctorate from The Open University in 2017.

  She is currently working on the sequel to this book, Curiosity and Its Science Mission: A Mars Rover Goes to Work . She resides in Los Angeles with her husband (who is not a planetary scientist) and two daughters.

  Index

  A

  Aeolis Mons

  aerogel

  animation

  announcement of opportunity

  anomaly

  argon

  Atlas V

  autonav

  autonomous navigation

  B

  Bagnold dunes

  battle short

  Bayer

  blind drive

  C

  calcium sulfate

  clast survey

  clay

  commissioning activity phase

  complexity

  conjunction

  CONTOUR

  cosmic ray

  curium

  D

  Deimos

  derivatization

  descope

  Dingo Gap

  dream mode

  dry-lubricated motors

  E

  epithermal

  ExoMars

  F

  Freon

  G

  guarded motion

  guided entry

  H

  habitability

  heater tables

  hematite

  HiRISE

  J

  JPEG

  JunoCam

  K

  Kimberley

  L

  local mean solar time

  local true solar time

  lockup

  M

  Maggie

  magic cylinder

  Marias Pass

  Mars Express

  Mars Reconnaissance Orbiter

  Mars Smart Lander

  Mars time

  microbes

  Morse code

  MTBSTFA

  O

  Odyssey

  olivine

  P

  Pahrump Hills

  Peace Vallis

  Philae

  Phobos

  Phoenix

  planetary protection

  plutonium

  portion plus

  R

  recurring slope lineae

  restricted sol

  runout

  S

  Scarecrow

  shrinkwrap stereo

  sidewalk mode

  Siding Spring

  sky crane

  slide sol

  soft short

  soliday

  special region

  supratactical

  surge sol

  T

  terrain mesh

  thermo-electric cooler

  TMAH

  traction control

  traversability

  tridymite

  V

  Vehicle System Testbed

  Vera Rubin Ridge

  visodom

  visual odometry

  Z

  Zabriskie plateau

  z-stack