Planetary and Space Science 165 (2019) 250–259

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Planetary and Space Science

journal homepage: www.elsevier.com/locate/pss

Exploring new models for improving planetary rover operations efficiencythrough the 2016 CanMars Mars Sample Return (MSR)analogue deployment

Eric A. Pilles a,*, M. Cross a,b, C.M. Caudill a, R. Francis a,c, G.R. Osinski a,g, J. Newman a,M. Battler a, M. Bourassa a, T. Haltigin e, V. Hipkin e, M. Kerrigan a, S. McLennan f, E.A. Silber d,K. Williford c

a Centre for Planetary Science and Exploration, Dept Earth Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canadab Dept of Electrical and Computer Engineering, University of Western Ontario, London, ON, Canadac Jet Propulsion Laboratory, California Institute of Technology, USAd Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, 02912, USAe Canadian Space Agency, John H. Chapman Space Centre, 6767 Route de L'A�eroport Saint-Hubert, Quebec, J3Y 8Y9, Canadaf Dept. Geosciences, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY, 11794, USAg Dept Physics and Astronomy, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada

A R T I C L E I N F O

Keywords:MarsRoverAnalogue missionSample returnMission operations

* Corresponding author.E-mail address: epilles@uwo.ca (E.A. Pilles).

https://doi.org/10.1016/j.pss.2018.10.001Received 5 January 2018; Received in revised formAvailable online 3 October 20180032-0633/© 2018 Elsevier Ltd. All rights reserved

A B S T R A C T

Approaches to rover mission operations were investigated in the framework of the CanMars Mars Sample Return(MSR) analogue mission deployments. Improving the efficiency of operations is a necessity for future planetarymissions, including Mars 2020, which seek to combine sample targeting with in situ investigations in the fixedamount of time available in primary science operations and with increasingly high public and science communityexpectations for results. Analogue missions provide an important opportunity to experiment with mission oper-ation strategies and learn lessons that can be incorporated in future missions. Improving the efficiency of oper-ations was a key objective of the 2015 and 2016 CanMars mission deployment. The mission overall operationsorganisation for CanMars is described with comparison to current implementation of Mars Exploration Rover andMars Science Laboratory missions. Approaches being tested included 3-sol plan sequences with increased use ofwaypoints for teach and return as part of a global Walkabout approach, use of Strategic Observation days to focusthe Science Team's efforts, and consideration to improvements in how information is exchanged tactically andstrategically in operations.

1. Introduction

A Mars Sample Return (MSR) effort would be one of the most chal-lenging planetary explorationmissions to date. Mission design for NASA'sMars 2020 mission provides at least one Mars year of surface operations(669 Martian sols) within which the mission must achieve its in situscience and sample selection and caching objectives (Mustard et al.,2013). This requires a significant increase in operations efficiency forsample targeting and selection compared to the Mars Science Laboratory,where the characterization of the first sample for coring was conductedbetween sols 166 and 181, and the first sample core for in situ analysiswas not acquired until sol 182 (Vasavada et al., 2014), with a second

12 June 2018; Accepted 3 Octo

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sample selected on sol 279. In comparison, the Mars 2020 mission isplanned to be capable of collecting at least 31 samples overall, with 20 inthe primary mission (Williford et al., in press).

In 2015, 2016, the Canadian Space Agency (CSA) and the Centre ofPlanetary Science and Exploration (CPSX) at Western Universityexecuted the CanMars Mars Sample Return (MSR) analogue mission(CanMars). During the analogue mission, over 60 people from 11 orga-nizations were organized into multiple teams. The Mission Control Teambased at Western (London, Ontario, Canada) was responsible for scienceplanning, processing, and interpretation (see Osinski et al., this issue, foran overview). The Mission Control Team was further split into Scienceand Planning sub-teams. The Planning Team consisted of engineers and

ber 2018

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

scientists and was responsible for planning the rover traverses and pro-ducing sol-by-sol activity plans compliant with the data, energy, and timebudgets. The Science Team consisted primarily of scientists and wasresponsible for processing and interpreting the scientific data and pro-ducing a science-driven plan each sol. The plans created by the MissionControl Team were executed by the CSA rover team in St-Hubert,Quebec, Canada, remotely operating the Mars Exploration ScienceRover (MESR) (Langley et al., 2012), built and supported by MacDonaldDettwiler and Associates Ltd. (MDA). The MESR is a six-wheeled roverwith a robotic arm equipped with a microscope and mini-corer that wasused during the 2015 campaign and part 1 of the 2016 campaign (seeOsinski et al., this issue, for rover specifications). The CSA rover teamwasresponsible for MESR activities, including rover traverses, acquiringpanoramic images and microscopic images, and positioning the roboticarm (Langley et al., 2012). A field team was also deployed with the roverwhich consisted of CSA engineers and Western geologists and wasresponsible for executing the plan mutually agreed upon by the MissionControl and CSA teams. The MESR rover and field team were located atan undisclosed field site in Utah (Fig. 1; Tornabene et al., this issue).

Approaches to rover mission operations were investigated within theframework of the CanMars MSR analogue mission deployment. Theseapproaches were designed and selected to act as reasonable extensions tothe current state of practice in rover operations, as used by the MarsExploration Rovers (MER) (Squyres et al., 2003) and Mars Science Lab-oratory (MSL) (Vasavada et al., 2014) missions. These missions, withyears of surface operations experience, use similar operations strategiesdriven by their instrument payloads, science goals, capabilities forcommunications with Earth, and available on-board power. Future mis-sions will build on this experience; NASA's Mars 2020 mission will use anMSL-like rover and payload suite to explore a new landing site, withambitious goals to complete that exploration and collect a suite of sam-ples (Mustard et al., 2013). Achieving such performance, on Mars 2020and other missions, will demand efficient and rapid progress that

Fig. 1. High resolution (60 cm/px) color image of the "landing site" in Utah.Quickbird-2 image provided by Hans van't Woud of Blackshore and its partners,including European Space imaging and EuroMoonMars research.

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manages to keep science information and scientific expertise in the loopfor decision-making. The CanMars team has identified that both in-novations in strategic planning, and increased on-board intelligence andautonomy, even using existing technologies, may provide the perfor-mance advances required for the ambitious rover missions of the comingyears. In the context of this research, “strategic plans” refers to plans thatare created more than one day in advance and are ready to be “uplink” atthe start of the tactical planning day. To this end, the CanMars simulationmade use of a collection of autonomy capabilities already demonstratedon Mars or on Earth (Francis et al., this issue), and tested strategies forrover planning.

The aim of this paper is to highlight planning, traverse, and autonomystrategies that were tested during the CanMars analogue mission anddiscuss how they affected the efficiency and efficacy of the planningprocess in Mission Control. Pre-planned rover traverses, designated asStrategic Traverse Days, were executed to eliminate the need for partici-pation from the Science Team in tactical planning for that sol (simulatedMartian solar days) and enabled the Science Team to process and inter-pret the immense data return with an extended science discussion.Additionally, during six command cycles of the 2016 CanMars mission(sols 22–39), a human field team simulated the activities of the MESR.During this Fast Motion Field Test (FMFT), 3 sols worth of activities wereexecuted each Earth day. This simulated multi-sol planning on a realMars mission and allowed the Mission Control Team to collect additionaldata and samples during their last week of analogue operations. In thisarticle, we describe the rover's instrumentation and limitations, the dailyoperations of the Mission Control Team, the methods involved with theseapproaches to mission planning, and the potential impacts this work mayhave on future Mars rover mission operations.

2. Daily operations and instrumentation

2.1. Instrumentation and resource utilization

The analogue mission simulated a rover with a suite of instruments(Osinski et al., this issue):

� Imaging instruments: mast-mounted camera for panoramic and pan-tilt-zoom images, belly-mounted hazard camera, and LiDAR (LightDetection and Ranging);

� Stand-off science instruments: SuperCam Laser Induced BreakdownSpectrometer (LIBS), Raman, VISIR (Visual and Infrared light), andRemote Micro Imager (RMI);

� Robotic arm-mounted contact science instruments: Three-Dimensional Exploration Multispectral Microscopic Imager(TEMMI) (See Bourassa et al., this issue, for details regarding the useof TEMMI), PIXL X-Ray Diffractometer (XRD), and SHERLOC Raman(Scanning Habitable Environments with Raman and Luminescencefor Organics & Chemicals); and

� Robotic arm-mounted drill and push core sampling instruments.

Science Activity planning followed realistic exploration and decision-making rules suited to the short-duration analogue campaign (Franciset al., this issue). Each command cycle was constrained by an operationalresource budget for the rover as shown in Table 1, and individual activitysequences consumed portions of that budget. Many of the activities haddependencies that required specific sequencing or multi-sol planningbefore they could be completed (Francis et al., this issue). Some of thedependencies and requirements were as follows:

� The simulation was modeled to require as a minimum a post-driveLiDAR scan and photographic imaging in the drive direction on soln to enable operators to plan the subsequent drive on sol nþ1.Therefore, the maximum distanceMESR could be continuously drivenin one sol before needing to take post-drive imaging was 83 m;

Table 1Daily operations budget and examples of activity resource consumption. Thebudgets during the FMFT were tripled.

Activity Duration(min) 360max

Data (kB)64,000max

Energy(Wh) 400max

RoboticArmActivity

Arm Deployment 45 5000 60TEMMI Deployment* 90 5000 60Instrument Switch OverDeployment

20 2000 20

Stowing Robotic Arm 20 500 45Solid Core Sampling 120 500 255Loose Soil Sampling 30 500 40Rock Abrasion 90 500 100

ContactScience

SHERLOC Ramanobservation (3� 3 grid)

20 2000 25

WATSON (Wide AngleTopographic Sensor forOperations andEngineering)Image Acquisition

2 3000 2

TEMMI B&W Imaging(high resolution)

30 2300 25

TEMMI Color Imaging(high resolution)

30 17,000 25

PIXL (PlanetaryInstrument for X-RayLithochemistry) X-RayObservation (3� 3 grid)

20 2000 30

Stand-OffScience

LIBS Measurement 5 300 5RMI Image Acquisition 1 1000 2SuperCam Power Down 1 10 1SuperCam Power Up 4 90 4SuperCam RamanMeasurement

5 300 2

VISIR Measurement 5 300 1Imagining Belly Image Acquisition 5 50 1

Context Camera ImageAcquisition

2 50 1

Panorama Acquisition 25 1000 25Zoom Image Acquisition(2592� 1944 px)

15 13,286 2

LiDAR Scan 20 1200 40MESR Rover Traverse (100m) 360 50,000 400

Wheel Digging 15 1 12

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

� Rover traverses were modeled to require 10min of initializationbefore movement;

� Imaging from sol n was required to target the stand-off science in-struments on sol nþ1;

� LiDAR and imaging of the arm workspace was required from sol n todeploy contact science instruments or sampling instruments on solnþ1, with no movement of the rover in between. The robotic arm wasmodeled such that once it was deployed with one instrument in po-sition, another instrument could be switched over without anotherfull deployment;

� The robotic arm had to be stowed before MESR could drive. Thesimulation allowed for the arm to be left deployed on sol n and thenstowed on sol nþ1; and

� Post-sampling documentation images were required after the armwasstowed; and

� The stand-off instrument suite had to be powered up before use. Oncepowered up, any of the stand-off instruments could be used beforebeing powered down.

2.2. Daily operations

The Operational Architecture (summarized in Osinski et al., 2012)and daily operations workflow (Osinski et al., this issue) were modifiedfrom recommendations by Francis et al. (2012) and Moores et al. (2012).The difficulties involved with this workflow are summarized by Bednaret al. (this issue). TheMission Control Teamwas comprised of two groups

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working in parallel: Planning and Science Teams. Mission Control for the2015 campaign largely comprised of consistent team members eachplanning cycle, many of which participated in the 2016 campaign.

MSER activity sequencing was completed within the Daily Operationsplanning spreadsheet tool to assess its feasibility with respect to MESR'sdaily resource limitations with respect to time (360min), data volume(64,000 kb), and power (240Wh). Resource costs for activities are listedin Table 1. Scientific targets for stand-off or contact measurements, aswell as potential drive locations, were selected by the Science Teambased on their potential for addressing the primary scientific objectives(summarized in Caudill et al., this issue), by using data from previous solsor available remote sensing data (see Tornabene et al., this issue, for adiscussion on remote sensing data used in this study). After a target waschosen, the Planning Team was responsible for ensuring the rover couldsuccessfully – and safely – complete the task, whether it was planning atraverse to a specific outcrop the Science Team selected, or confirmingthat the arm could be positioned for contact science at a particularoutcrop. Sequencing was primarily an iterative process between theScience and Planning Teams, wherein a plan was proposed and assessedwith revisions made as necessary. An operations software packagedeveloped and provided by CSA (Symphony in 2015, Apogy in 2016) wasused to plan, validate, execute, and monitor integrated operationsthroughout all stages of the planning process.

The planning process for a given sol is show in a flow chart in Fig. 2.Planning for sol n began with the downlink of data from sol n-1 at 19:00on sol n-1. The sol n-1 data was reviewed by the Science Team. Resultsfrom sol n-1 image inspection and data analysis informed the desiredactivities for sol-n in association with mission objectives. The desired sol-n activities, including rover traverse and science instrument utilization,were provided to the Planning to assess for feasibility with respect toMESR's resource and traversability constraints. Activities were added orremoved in collaboration with the Science Team in an iterative process.At 21:00 of sol n-1 the Planning Team walked through the sequenced soln plan to ensure it complied with the Science Team's intentions. TheMission Control Team reconvened at 07:00 on sol n to make final ad-justments to the sequenced plan; these were often minor adjustments tothe parameters of the activities and not to the sequence itself. The finalsequenced sol n plan was uplinked by the 08:30 deadline. From 08:30 to09:00, the CSA and field teams reviewed the plan. At 09:00 the MissionControl Team called the field team to clarify any inconsistencies withinthe document, after which the field team begins executing the plan. From09:00 to 10:00 the Mission Control Team began pre-planning for sol nþ1.

When formulating the sequenced plan, maximization of budget usagewas considered for purposes of enhancing the scientific yield. Addition-ally, the activity order in the sequence was considered, particularly forimaging operations where sun angle was important. Often, the teamapplied a form of planning triage, where certain activities were weighedagainst others with respect to their resource allocation and expectedreturns. Activity selection was based on both achieving the missionqualifications for success, as well as the Mars Exploration ProgramAnalysis Group (MEPAG) science goals (see MEPAG goals document,Mustard et al., 2013).

2.3. Effect of daily resource constraints on daily activity planning

The robotic arm activity was resource intensive, which required theScience Team to decide if a target was worthwhile to sample. Due to boththe daily budgeting constraints (Tables 1 and 2) and the overall missionduration limit, sample acquisition was often performed within the samerobotic sequence as contact science measurements; the decision to sam-ple was often based on stand-off science measurements and not on con-tact measurements, and the contact measurements were taken just priorto sampling to provide additional scientific context for the sample. Thefull robotic arm activity of contact science and solid drill core samplingcould not be completed within one sol and thus required carefulconsideration.

Fig. 2. (right). Flowchart of plan delivery. Approximate times in bold.

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

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Generally, resource efficiencies were quite high, thanks to meticulousplanning (Table 2). The rover traversed a total distance of 990m. Theaverage efficiency for duration, data and energy budgets was 96.6%,91.1% and 78.7%, respectively. Duration was the most commonlydepleted resource; even when plans were duration-limited, it was com-mon for one or both other resource budgets to be nearly maximized(Table 2). The total number of scientific measurements and samples arereported in Table 3.

Table 2Resource consumption per sol as a percentage of available budget and traversedistances completed for each sol. Note that for sol 11, ‘out-of-sim’ logisticsconstrained the available duration of the field activities. The science activitieswere planned to fully make use of the available duration. Bolded values indicatelimiting resource for given sol. Sols with an * indicate sols where samples werecollected.

sol MissionPhase

Time(%)

Data(%)

Energy(%)

Distance(m)

CumulativeDistance (m)

20151 2015 –

Rover93.33 91.25 46.50 26 26

2* 2015 –

Rover91.25 43.05 95.00 0 26

3 2015 –

Rover95.00 93.39 100 72 98

4 2015 –

Rover85.10 99.67 72.35 26.1 124.1

5* 2015 –

Rover91.67 81.54 99.50 0 124.1

6 2015 –

Rover100 94.93 76.75 40 164.1

7 2015 –

Rover99.03 96.18 69.75 19 183.1

8 2015 –

Rover100 66.04 70.00 10 193.1

9* 2015 –

Rover100 97.66 98.50 0 183.1

10 2015 –

Rover99.58 99.81 76.75 41 234.1

11* 2015 –

Rover100 96.25 51.25 0 234.1

2016 - MESR12 2016 –

Rover99.7 97.5 90.5 62 296.1

13 2016 –

Rover99.2 66.0 80.5 0 296.1

14 2016 –

Rover99.2 93.1 97.3 80 376.1

15 2016 –

Strategic99.9 92.8 71.8 28.5 404.6

16 2016 –

Rover99.6 99.2 58.0 0 404.6

17 2016 –

Rover97.4 99.9 88.0 0 404.6

18 2016 –

Rover100.0 88.9 72.8 0.9 405.5

19* 2016 –

Rover73.6 99.7 97.5 0 405.5

20 2016 –

Strategic99.9 97.5 76.0 30 435.5

21 2016 –

Rover99.6 88.7 96.0 29.5 465

2016 - FMFT22–24 2016 –

FMFT99.6 98.2 64.3 54 519

25–27 2016 –

FMFT99.9 99.0 71.6 115.5 634.5

28-30*

2016 –

FMFT97.9 91.5 77.6 105 739.5

31-33*

2016 –

FMFT99.1 98.5 74.4 91 830.5

34-36*

2016 –

FMFT98.8 93.4 77.7 85 915.5

37–39 2016 –

FMFT90.9 97.0 74.9 74.5 990

Table 3Science measurements acquired by instrument.

Measurement 2015 (11sols)

2016 Rover(10 sols)

2016 FMFT(18 sols)

Panoramas 7 4 4Zoom Images 25 15 38Belly Cam Images 30 4 3LiDAR Scans 8 7 9TEMMI 2 0 0PIXL X-Ray Observation (3� 3 grid) 2 3 4XRF (X-Ray Fluorescence)Measurements (SuperCam LIBS)

33 60 142

Raman Measurements (SuperCamRaman)

32 57 149

SuperCam VISIR Measurements N/A 52 125SuperCam RMI Image Acquisition N/A 39 54SHERLOC Raman Observation(3� 3 grid)

N/A 3 4

WATSON Image Acquisition N/A 17 19Context Camera Image Acquisition N/A 3 4Rock Abrasion 0 2 0Drill Core Samples 2 1 0Push Core Samples 2 0 3

Fig. 3. Zoom images of the Horik outcrop. Yellow dots represent locationschosen autonomously for RMI-LIBS–VISIR-RAMAN targets. A: A zoom image ofthe Horik outcrop acquired during sol 12. B and D: Zoom images of the Horikoutcrop acquired during sol 15. C and E: Autonomous classification of zoomimages B and D.

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3. Strategic traverse days

Two pre-planned operations were executed on sols 15 and 20 to testthe efficiency of remote science operations with pre-planned strategicobservations. During these Strategic Traverse Days, the rover was com-manded to drive towards a pre-determined feature of interest and acquirepost-drive imagery and remote science measurements. No tactical inputfrom the Science Team atWestern was required for these operations, thusallowing them to focus on an in-depth science discussion. Pre-planning ofa kind has already been done on Mars rover missions – 3-sol Friday planson the Mars Science Laboratory mission, for example, have largely freedthe science team fromworking weekends (Vasavada et al., 2014), by fullyplanning the weekend sols ahead and uplinking commands for thoseactivities with those for Friday. During mission phases where emphasison mobility was increased, such as the rapid traverse period on MSL, thatmission's team developed a prioritized list of systematic observations thatcould be slotted around drives (Vasavada et al., 2014) – allowing plan-ning of some science without significant daily involvement of the scienceteam by using ‘canned’ reusable or slightly adjustable observations. Inthe case of the CanMars analogue mission, the intent was to furtherextend this concept, by having not only pre-developed observations, buta fully pre-developed plan which was prepared several days ahead oftime, and independent (or very little dependent) on events in the missionbetween when it was planned and when it would be executed. In Can-Mars 2016, our strategic traverse days involved a traverse with post-driveimages, LiDAR scans, and blindly- or automatically-targeted stand-offscience (see Francis et al., this issue, for details on autonomous science).In this section we describe how strategic traverse days were usedthroughout the analogue mission, and how they impacted the planningprocess.

The major benefit of including pre-planned strategic traverse days wasthat it provided the Science Team with the much-needed time to interpretthe immense amount of scientific data that was collected. This time wasused to produce sedimentary facies models of the landing site region basedon the imagery collected thus far. The highest priority mission goals for the2016 CanMars mission were focused on paleoenvironmental habitabilitypotential and preservation of ancient biosignatures from organic-richcarbon. The predictive stratigraphic model gave us the tools to indicatelithologies and specific outcrops likely to have preserved biosignaturesmany sols in advance of acquiring data on the targets of interest. Using thisinformation, we could make a long-term strategic mission plan which wasvery focused on rich data return and sample acquisition. The StrategicTraverse Days were important for successful targeting and acquisition ofpotentially organic-rich shales, for example.

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3.1. Strategic traverse day 1: sol 15

The first strategic traverse day was scheduled for sol 15, and consistedof a long traverse towards the Horik region (Outcrop in Fig. 3A). Thislocation was selected as a destination because panoramic images fromprevious sols, in addition to orbital images, led the Science Team tobelieve that the Horik region may consist of a similar caprock material tothat seen at Jotunheim, but was more readily accessible than Jotunheim;potential preservation of softer sediments directly underlying a protec-tive capping unit was determined a primary target for investigation.Thus, the rover had only 3 sols to acquire any images and/or measure-ments in the region surrounding Jotunheim before departing for Horik.The only lithologic unit that had not been examined in detail thus far wasthe sandstone unit at the base of Jotunheim. Sols 12 and 13 were spentcollecting remote and contact science of the lower sandstone unit, andthus filling this gap in information.

At the end of sol 13 a large boulder on the southern slopes ofJotunheim was imaged, and the Science Team was curious if this newfeature displayed evidence of cross-bedding, which could be indicative ofwater flow. The possibility of cross-bedding complicated the plan for sol14, forcing the team to decide between blindly acquiring additionalimages (and possibly remote scientific measurements) of this boulder, orabandoning it and traversing towards Horik. If the close-up images of thisboulder showed something particularly interesting it would be too latefor the rover to examine it, since on the following sol it would betraversing towards Horik. Ultimately, the Science Team decided to driveaway from Jotunheim before seeing the blindly acquired images of itssouthern slopes. Ideally, the Science Team would have had the ability tochange the strategic traverse day to sol 16, which would allow them tospend an extra sol exploring the southern slopes in more detail beforemoving on to the Horik region. In this case, the inclusion of a pre-plannedtraverse on sol 15 limited the potential activities of the rover during theprevious sols.

Fig. 5. A: Panorama acquired at the end of sol 20 showing the location ofseveral features of interest. B: Zoom images acquired during sol 20. Yellow dotrepresents locations chosen autonomously for RMI-LIBS–VISIR-RAMAN target.C: Autonomous classification of zoom images B.

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

Although the general plan for the first strategic traverse day wasdecided at the start of the 2016 mission (i.e., a traverse towards Horikwith post-drive images and stand-off measurements), the exact drivedistance required to get close to Horik was not known. Once anapproximate end-of-day location for the rover on sol 14 was known, thesol 15 strategic traverse day plans could be finalized. In practice, thismeant that the strategic traverse day plans were finalized two days priorto execution. The strategic traverse day consisted of a 30m traverse to-wards Horik with a post-drive panorama image and 360� LiDAR scan. Azoom image was also acquired of the capping rock material and thenearby ‘regolith’ (Fig. 3B and D). These images were used to autono-mously target two different rock types with SuperCam measurements(Fig. 3C and E). Autonomous geological classification was implementedin the 2016 analogue mission (Francis et al., this issue), in part to facil-itate planning for the strategic traverse days. For further details regardingthe use of autonomy during the analogue mission, see Francis et al. in thisissue. If the Science Team had been involved with the tactical planningfor this strategic traverse day, it is unlikely that the plan would havechanged, given that the Horik outcrop was a new location, and manuallytargeting SuperCam measurements at the post-drive location would nothave been possible with the information available at planning time, priorto the drive.

3.2. Strategic traverse day 2: sol 20

During sols 16 and 17, the rover collected remote scientific mea-surements and images of the rocks in the Horik region. The Science Teamidentified one rock referred to as Hans, which appeared to containendoliths (Caudill et al., this issue). As this location was deemed scien-tifically significant, the teams prepared this site as a candidate for samplecollection. Sols 18 and 19 were spent collecting in-contact science atHans and sampling. Having collected a sample from the Horik region,and collected sufficient scientific measurements of the surrounding rocksfor context, the rover was ready to traverse to the Ragnarok region duringthe second strategic traverse day.

There were some difficulties involved with planning sol 20, primarilywith the route chosen for the traverse. Originally, the intent was to drivedirectly to Ragnarok from Horik through the channel indicated in Fig. 4.However, upon arriving at Horik it was clear that the path forward wasmore difficult to traverse than anticipated due to steep slopes and thepresence of large boulders that were not visible in the digital elevationmodel that was used by the Science Team for planning such routes. As aresult, the rover was forced to backtrack significantly to maneuveraround the obstacles (blue line in Fig. 4). As with the previous strategictraverse day, the drive ended with a panorama image (Fig. 5A), 360�

LiDAR scan, a blindly targeted zoom image of the rocks to the left of therover that were obstructing its path (Fig. 5B), and SuperCam measure-ments of two rock units in the image that were autonomously targeted(Fig. 5C). Due to the difficulties involved with planning the traverse forthis sol, the Planning Team was forced to provide tactical input for the

Fig. 4. Original and final traverses for the second Strategic Traverse Day.

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sequencing plan, which meant that several members of the PlanningTeam were unable to participate in the scientific discussion during thisStrategic Traverse Day. Since members of the Mission Control Team hadto provide tactical input regarding the traverse, this no longer counted asa strategic day. However, all members of the Science Team were able toattend the discussion.

3.3. Strategic traverse day observations and recommendations

Immediately following the mission, 17 members of the science andPlanning Teams reported their observations on the efficiency of opera-tions with and without the implementation of strategic days. 85% ofthose who responded felt that the strategic science planning daysenhanced the ability of the team to select targets in the regular ScienceTeam operations days that followed. Reasons included that strategic daysgave the Science Team time to “digest information”, helped for long-termplanning and keeping the team focused on mission goals, allowed for thefocus to be shifted from a daily perspective to a strategic one, and gavethe team a better understanding of the big picture. However, it was notedthat due to the inflexible scheduling of strategic days, they causedadditional pre-planning that took extra time on other days. When askedhow strategic observation day activities should be scheduled during areal mission, there was a clear difference in responses from Science Teammembers as compared to Planning Team members. The majority of theScience Team members suggested that one strategic days should beincluded at each region of interest (e.g., the Jotunheim or Horik regionsin Fig. 1). In this way, the rover would not be forced to drive away from alocation when the Science Team was not prepared to do so. All membersof the Planning Team recommended that strategic days should beincluded at regular intervals (i.e., weekly or every two weeks), but rec-ommended that the Science Team have the capability to choose a daythat would be appropriate and would not interrupt their plans. During areal mission, this could correspond with pre-scheduled weekends, as isdone with theMSL (Vasavada et al., 2014), or on days off, or known timeswhen the Science Team would be out of communication with the roverfor multiple days due to limited satellite communications or anotherreason.

4. Three-sol plans

During part two of the CanMars 2016 Mars Sample Return Missioneach Earth day corresponded to 3 sols’ worth of activities, executed by ahuman field team in place of the MESR rover (i.e., the FMFT). Thissimulated a phase of reduced communications opportunities, such as the

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

type to be expected should a Mars rover have to rely on only a non-sun-synchronous orbiter for data relay (Gaines et al., 2016). This part of themission was implemented to increase the amount of scientific data andsamples received during the mission. The human field team had the samerestrictions as the rover, however, two new simulated capabilities wereincluded: (1) Autonomous geological classification, which allowed the“rover” to autonomously classify units in an image and target them withremote measurements, and; (2) Conditional sequencing, which allowedthe “rover” to carry out a different plan if certain conditions were not met(see Francis et al., this issue). These autonomous capabilities wereincluded to test the functionality of TextureCam classification in the field(Francis et al., this issue), as well as to increase the productivity the 3-solplans.

While the FMFT was simply intended to increase scientific return in alimited time, the planning required to create consecutive 3-sol plans ledthe Science Team to test an alternative approach to rover exploration thatbegan with a reconnaissance stage involving long traverses with minimalimaging and scientific acquisition to gain context and to prioritize targets(i.e., the “Walkabout”). This is similar to the way a terrestrial geologistwould perform a cursory survey of a field site before any detailed ex-amination is performed. This type of exploration has been used on Marsin the past, when MER Opportunity examined Whitewater Lake (Arvid-son et al., 2014) and when MSL Curiosity investigated the Pahrump Hillsregion (Vasavada et al., 2014). Similar exploration strategies were alsotested at using a semi-autonomous rover by Yingst et al. (2017) in a fieldsite close to the CanMars “landing site”. These authors found that thewalkabout strategy saved time and other mission resources, andimproved overall scientific return. In this analogue mission scenario, webuilt on the success of these previous endeavors and tested a walkaboutstrategy with increased autonomous capabilities and multi-sol planning.

The flight rules for the human field team were identical to that of therover. One of the most critical rules that influenced the planning strate-gies utilized was that before the rover could collect a sample, a work-space LiDAR scan and image were required of the site intended forsampling. Because of these limitations, sampling and/or contact sciencecould only be completed on the first sol of a 3-sol plan, and only if aLiDAR scan and image had already been acquired of the workspace. Thismeant that at the end of every 3-sol plan an image and LiDAR scan wasacquired of the workspace directly in front of the rover so contact scienceand/or sampling could be completed on the following sol if desired.Another important capability of the FMFT was the rover's ability toprecisely return to a position and orientation it had previously been byfollowing a previous route. This allowed us to “save”waypoints the roverhad previously visited and return to them to perform human-targetedremote science using imagery acquired in a previous sol. However, it isimportant to note that due to cm-scale rover positioning uncertainties,smaller features could not reliably be human-targeted using co-ordinateframes from previous visits (Francis et al., this issue). These flight rulesand limitations – both old and new – had significant implications on theplanning process for the FMFT. Further discussion on the difficultiesinvolved with creating multiple plans are included in Bednar et al. (thisissue).

4.1. Pre-planning: considerations for creating 3-sol plans

Special considerations had to be made when creating 3-sol plans.During normal rover activities, the Mission Control Team would receivedata from the rover after every sol, which allowed them to adjust theirplans for the following sols according to what the rover imaged and/oranalysed throughout the day. However, in the case of the FMFT, theMission Control Team only acquired data from the rover after 3 sols ofactivities, which meant that the Mission Control Team had to fill 3 sols’worth of activities without the benefit of receiving feedback from therover in-between these sols. During the FMFT, ground-in-the-loop cyclesonly occurred once every 3 sols, greatly increasing the importance ofstrategic-level thinking because of how rapidly sols can be wasted if the

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team did not plan ahead accordingly. Because of these limitations, all 6command cycles of the FMFT had to be planned well in advance to makethe most efficient use of time. These limitations inherent to 3-sol plansled to the concept of the Walkabout, which was an essential part ofcreating consecutive 3-sol plans.

The Walkabout involved traversing to multiple locations during thefirst 3-sol plan and “saving” these waypoints using the rover's precisereturn functionality. At each of these locations one or more images wereacquired of the workspace or of features of interest identified from thepre-drive location. Each of these images was autonomously classifiedusing the TextureCam software, and remote scientific measurementswere acquired from each major geological unit visible in the image. Thisprocess acquired scientific data from multiple sites without requiring theScience Team to manually target specific points. It also created 3 reusablewaypoints that the rover could return to at any time to performed human-targeted remote measurements using the images obtained during theWalkabout. Each successive 3-sol plan consisted of some combination ofcontact science/sampling, returning to a previous waypoint for human-targeted remote science, and/or traversing to a new waypoint and per-forming autonomously-targeted science. The long-term plan is summa-rized in Table 4, which compares the original plan to the final executionof the FMFT. In the following section, we will provide an overview ofeach command cycle.

4.2. Execution of 3-sol plans

The Walkabout was executed as planned, saving three new waypointsand acquiring remote scientific measurements autonomously (Fig. 6A).The second plan was spent returning to each of these three sites andtargeting specific units manually for additional measurements, as well assaving two new locations (Fig. 6B). The plan ended with imaging and aLiDAR scan of the workspace in front of the rover in preparation forsampling following day. The Mission Control Team decided that the planmade an efficient use of the data and time available throughout the three-sol plan, that the remaining command cycles were planned in a similarway (Fig. 6C to E). First, contact science (e.g., Raman, XRD) and thematerial within the workspace would be sampled. Then, the rover wouldreturn to one of the “saved” waypoints and completed human-targetedremote scientific measurements. Finally, the rover would drive to anew waypoint and target it autonomously. The final activity would beobtaining images and a LiDAR scan of the workspace in front of the roverin preparation for the following day. The final plan was spent collectingadditional context science for the samples that were acquired, and endingwith a long traverse into a new region for new imaging (Fig. 6F).

One of the major changes between the original plan and the final planwas that new waypoints were continually “saved” throughout the week(Table 4). In the original plan, the three saved waypoints during theWalkabout were the only sites visited for scientific measurements andsampling during the FMFT. In reality, the geology at each individuallocation was not diverse enough to warrant a large number of stand-offmeasurements. Because of this, returning to an old location to performhuman-targeted science did not fill the data or time budgets available for3 sols. At each of these new locations, autonomous targeting was used tocollect stand-off measurements (grey boxes in Table 4). As a result,during each command cycle old waypoints were revisited for human-targeted scientific measurements and new waypoints were “saved” andautonomously-targeted for remote scientific measurements (e.g., thewhite points in Fig. 6).

Towards the end of the mission (planning for sols 34–36), the teamhad not yet tested one of the two new simulated capabilities that wereincluded during the FMFT: conditional sequencing. The team decidedthat this could best be used to decide the final drive location on sol 36.During the 5th command cycle (Table 4, sols 34–36), conditionalsequencing was used for the first time to change the outcome of the planbased on scientific measurements. The Science Team suspected that therock Sigurd shown in Fig. 7A contained kerogen, which is a mixture of

Table 4The long-term plan for the Fast Motion Field Test before execution (top) and after execution (bottom). Major changes to the final plan are shaded in grey.

sols 22–24 sols 25–27 sols 28–30 sols 31–33 sols 34–36 sols 37–39

OriginalPlan

Walkabout: Autonomousscience at newwaypoints

Contact science &abrasion

Contact science &sampling

Contact science &sampling

Contact science &sampling

Uncertain

Human-targeted scienceat previous waypoints

Human-targeted scienceat previous waypoints

Human-targeted scienceat previous waypoints

Human-targetedscience at previouswaypoints

Final Plan Walkabout: Autonomousscience at newwaypoints

Human-targeted scienceat previous waypoints

Contact science &sampling

Contact science &sampling

Contact science &sampling

Human-targetedscience at previouswaypoints

Autonomously-targetedscience at new waypoints

Human-targeted scienceat previous waypoints

Human-targeted scienceat previous waypoints

Human-targetedscience at previouswaypoints

Long rover traverseto new region

Autonomously-targetedscience at new waypoints

Autonomously-targetedscience at new waypoints

Conditionalsequencing

Fig. 6. The rover path taken during the Fast Motion Field Test. The backgroundis a digital elevation model of the landing site, overlain with a slope map. Greenindicates slopes from 0 to 10�, yellow indicates slopes from 10 to 15�, and redindicates slopes >15�. Unless otherwise noted, new sites were autonomouslytargeted for stand-off science when first visited. A: The Walkabout, during whichthe rover traversed to 3 new locations that were autonomously targeted forstand-off science. B: The rover performed contact science at its current site,drove to a new location, returned to the 3 sites visited during the Walkabout toperform human-targeted observations, and ended at its first sample site. C: Therover collected a sample, drove to 2 new locations for autonomously-targetedscience and one old location for human-targeted stand-off science, and endedat a new location in preparation for sampling. D: The rover collected a sample,drove to 1 new location to acquire a panoramic image and LiDAR scan, andreturned to 3 previous locations for human-targeted stand-off science. E: Therover collected a sample and traversed to a previous location to perform human-targeted stand-off science, which was used with conditional sequencing todetermine the end-of-drive location (see Fig. 7 and accompanying text). F: Therover performed contact science at its current location and returned to thesampling sites to acquire human-targeted remote measurements before drivingto a new region.

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organic chemical compounds that make up a portion of the organicmatter in some sedimentary rocks (Durand, 1980; Vago et al., 2017). TheRaman instrument can detect kerogen, as shown in Fig. 6B. Rocks visu-ally similar to Sigurd had been previously observed from a distance, butnot measured. If the rock contained kerogen, it would be a very highpriority target for sampling. Therefore, the Science Team issued a com-mand to the rover stating that “If the Raman instrument detects peaks at1354 and 1603� 15 cm�1, then follow alternate path to Sigurd (blackpath in Fig. 7C). If one or both peaks are absent, proceed along theoriginal path (blue path in Fig. 7C)”. The result was that kerogen was notdetected by the Raman instrument, and thus the blue path was taken inFig. 7C. See Francis et al. (this issue) for further discussion.

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5. Implications for future missions

The implementation of pre-planned strategic traverse days and multi-sol plans led to the development of unique strategies for missionplanning.

The amount of scientific data return was immense, and the additionaltime allotted for scientific discussion during the strategic traverse dayswas essential to allow for meaningful interpretation of the data. After themission, the Mission Control Team was surveyed to determine the effi-cacy of the tactics employed during the CanMars mission, in particularthe inclusion of the strategic traverse days. Eighty-five percent of theteam felt that the strategic traverse days enhanced the ability of the teamto select targets in the regular Science Team operations for following sols.Those surveyed found that the strategic traverse days “Gave [the ScienceTeam] time to digest information …” and “… allowed for the focus [ofthe team] to be shifted from a daily perspective to a strategic one.” Theextended discussion also allowed for “a good opportunity to look at im-ages and observe without debating”, providing time to interpret the datawithout the stress associated with meeting a deadline. This additionaltime allotted for scientific discussion led to a more developed deposi-tional model of the region and helped select appropriate targets forsampling during future sols.

However, the inclusion of pre-planned traverses forced the MissionControl Team to move on to a new region of study (i.e., from Jotunheimto Horik) before they had retrieved all the data they required from thatregion. Those surveyed found that “Having it [strategic traverse days] setto a specific day was limiting to the plan”, and one team member foundthat “… science discussions were compromised” due to the inflexibility ofthe pre-planned activity. For future rover operations, pre-planned ac-tivities should be included to provide a break from tactical planning forthe Science Team, however it should not come at the expense of the re-turn of scientific data. In the survey, the Science Team believed that onestrategic traverse day should be planned with each local area of interest(e.g., one for Ragnarok, one for Hel, etc.), while the Planning Teambelieved that strategic traverse days should occur regularly at pre-determined intervals (i.e., weekly, or once every two weeks). It is rec-ommended that strategic traverse days be implemented frequently –

perhaps once a week – and allow the Mission Control Team to selectbetween two possible days, rather than being restricted to a certain day.These changes would allow the team to fit a long pre-determined traverseinto their plans easier.

Creating and executing six 3-sol plans in a row was a difficultendeavor and several important lessons were learned. It provided theteam with an opportunity to test a novel way of exploration that involveda reconnaissance stage (i.e., the “Walkabout”). This method of savingwaypoints for further exploration in the future was essential to filling the3-sol plans, and ultimately led to a rover path that very much resembledthat of a field geologist rather than traditional rover explorationmethods. One major drawback to multi-sol planning was running out of

Fig. 7. The conditions and possible results of the conditional sequencing attempted during sols 34–36. A. The rock analysed with the Raman instrument. B. Ramanpeaks at 1354 and 1603� 15 cm�1, indicative of the presence of kerogen. C. Possible rover traverses depending on if kerogen was detected.

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

activities to fill the 3-sol plans. Because the initial reconnaissancecovered only a small area, the team quickly exhausted the remote scienceand imagery they could acquire, and were forced to slowly expand theirlist of “saved” waypoints. In this case, the outcrops visited during thisreconnaissance were quite close to each other, but in future missionoperations a rover could routinely complete a similar Walkabout on amuch larger scale, quickly obtaining geological context for a larger re-gion before deciding which areas require sampling. Additionally, it is notrecommended that multi-sol plans be executed so frequently. The amountof work involved with creating so many multi-sol plans in a row wasexhausting to the team.

Based on the results of this study, the following recommendations aregiven regarding the use of pre-planned strategic traverse days and multi-sol planning for rover mission operations with autonomous capabilities:

1. The additional time allotted for scientific discussion during the stra-tegic traverse days was essential for the Science Team to interpret thelarge amount of data. However, they should not be pre-allotted plansthat could potentially jeopardize the scientific return. Therefore, it isrecommended that mission operations consider including strategictraverse days for traverses between sites of interest that can beimplemented when it is convenient for the rover to leave a location.

2. The “Walkabout” strategy of exploration was extremely effective atacquiring images and stand-off measurements of a new regionwithout feedback from the Science Team. Walkabouts are recom-mended as a potential strategy for rover missions on arrival at newsites whose scale and layout lend themselves to this approach. Whilesome investigation sites will lend themselves to a linear survey, theJotunheim region was comprised of a diverse group of interrelatedunits exposed at several locations all within a distance of 1–3 drives ofeach other. When the site geography suits it, the walkabout approachallows the mission team to quickly determine the general geology anddiversity of the site and select potential sites for focused study andsampling.

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3. Multi-sol planning is an effective way to acquire a large amount ofdata with limited feedback from the Mission Control Team. However,planning back-to-back multi-sol plans is not recommended, as it leadsto exhaustion for the team and general inefficiency/repetitiveness inthe later command cycles. It is recommended that multi-sol plans beused sparingly, such as how they are implemented on Fridays for MSLto provide the team with a much-needed break over the weekend(Vasavada et al., 2014). Notably, while CanMars planned 3-sol plansonce per day for six days in a row, a real-time implementation of thisapproach would reduce this pace to producing a 3-sol plan every 3days. While reducing the heavy workload, the planning days wouldstill require the increased workload of assessing 3 sols of downlinkand planning 3 sols of uplink activities.

4. Post-drive autonomous target selection greatly enhances the value ofmulti-sol plans, by allowing rich surveys of one or several sites withremote-sensing instruments to be executed quickly in a single uplinkcycle. The availability of autonomous targeting of this type greatlyenhances the data return and consequent pace of the walkabout, if aground-in the-loop cycle is only possible every few sols.

The results that emerged from this exercise are of course, in theirdetails, driven by the particular mix of instrumentation used in thesimulated mission, and by the geography of the field site and the sciencegoals in play. In general, the planning strategies apply to any missionwith a similar mix of instrumentation – mast-mounted cameras andremote spectrometers, with arm-mounted instruments – carried on amobile system capable of moving tens to over 100m per plan. In thissense, the CanMars experience is broadly comparable to the Mars 2020mission (on which the CanMars payload was based) and the plannedExoMars rover. Autonomous capabilities – especially the autonomouspost-drive targeting – also significantly influence the efficiency andstrategy of planning, and are again reflective of the capabilities expectedfor Mars 2020. Understanding the influence on planning of the autonomycapabilities was a primary goal of the CanMars project, and based on this

E.A. Pilles et al. Planetary and Space Science 165 (2019) 250–259

experience we see value for numerous potential missions (see Franciset al., this issue).

Acknowledgements

We would like to thank the CSA, international guests (from NASA,UKSA, DLR, and other institutions), and the entire CanMars team for theirhard work and dedication. This work was funded by the Natural Sciencesand Engineering Research Council of Canada's CREATE program and theCanadian Space Agency. This CSA Mars Exploration Science Rover(MESR) used in this exercise was built by MacDonald, Dettwiler andAssociates Ltd. (MDA). The analogue mission was carried out in part-nership between the Canadian Space Agency and the Centre for PlanetaryScience and Exploration (CPSX) at the University of Western Ontario, aspart of the NSERC CREATE project “Technologies and Techniques forEarth and Space Exploration” (create.uwo.ca). Part of this research wascarried out at the Jet Propulsion Laboratory, California Institute ofTechnology, under a contract with the National Aeronautics and SpaceAdministration. We would like to acknowledge Hans van't Woud ofBlackshore and its partners, including European Space imaging andEuroMoonMars research for the use of the color Quickbird-2 image thatcovers the analogue mission site.

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