Mechanism Design and Some Challenges from Perseverance CL24_6225.pdf

Mechanism Design and Some Challenges from Perseverance sampling and chaching system

1. 1
Mechanism Design & Some
Challenges from Perseverance’s
Sampling & Caching System
Presentation to MIT 16.853 class
Louise Jandura
Sampling & Caching Chief Engineer
December 3, 2024
Mechanical
Engineering
Division Chief
Engineer
JPL Fellow

2. 2
Massachusetts Institute of Technology
(MIT)
Course 2 – Mechanical
Engineering
Bachelors and Masters Degrees
(particular interest in design and
controls)

3. 3
Jet Propulsion Laboratory
Louise
Jandura
Working at
JPL
Image Credits: NASA/JPL-
Caltech
35 years at
JPL
SRTM (Shuttle Radar
Topography Mission)
Genesis
MER (Mars
Exploration Rover)
Aquarius
MSL Curiosity (Mars
Science Laboratory)
Curiosity Operations
Mars 2020
(Perseverance)
Perseverance
Operations
Mechanical Division
Chief Engineer

4. 4
Seeking mastery is a continuous
journey…
Various technology
projects
SRTM (Shuttle Radar
Topography Mission)
Genesis
MER (Mars
Exploration Rover)
Aquarius
MSL Curiosity (Mars
Science Laboratory)
Curiosity Operations
Mars 2020
(Perseverance)
Perseverance
Operations
Mechanical Division
Chief Engineer
Support Engineer
Cognizant Engineer
Mechanisms Lead
Mechanical System
Engineer
Sampling Chief Engineer
Operations Experience
Sampling & Caching Chief
Engineer
Division Chief Engineer
The job I had been
preparing for my
entire career but I
didn’t know it.
EVERY
JOURNEY IS
DIFFERENT.
THIS IS MY
JOURNEY

5. 5
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oDEFINE/ARCHITECT
lDefine the “Chunks of the System” & Identify the Challenge Areas
lDistribute Functionality among the “Chunks of the System” & Determine
Approach to Key Requirements
lPerformance & Interface Requirements, Resources (mass, power, volume,
schedule, etc)
lWhat can be done vs. what needs to be invented
oDESIGN
lDevelopment testing – gain understanding & fix problems
lDetails matter
lMargin – force/torque, deployment, mass, volume
lPerformance & Fault Protection (often the design driver)
oFABRICATE/PROCURE/ASSEMBLE/TEST
lQualify, Prove Robustness & Performance, Characterize & fix problems
What does a mechanism engineer
do? 1/2

6. 6
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oINTEGRATE INTO NEXT LEVEL OF ASSEMBLY/TEST SOME MORE
lQualify, Prove Robustness & Performance, Characterize
lFix problems
oLAUNCH (if you are part of a spacecraft)
oLAND (if you are a Mars Rover)
oOPERATE
lComplex electromechanical devices / subsystems tend to have more
mechanisms engineers from the development cycle during the early part of
operations
lTell the Rover what to do each sol (Martian day)
lAnalyze Rover Health and Performance
lFix problems
What does a mechanism engineer
do? 2/2

7. 7
Comparing Genesis with
M2020
nGenesis
oLargely deployment
mechanisms that have a single
valued operating state (eg.
Open/Closed)
oStraightforward performance
evaluation
nM2020 Perseverance Rover
oHighly integrated mechanisms
& software to perform the
required scientific functions
oLarge range of operating states
by design
oMore detailed knowledge of the
hardware needed to evaluate
performance
oEvaluate design limitations v.
requests for operational
flexibility
Genesis payload integrated
with the Sample Return
Capsule and the spacecraft
M2020 Perseverance
Rover

8. 8
Curiosity and
Perseverance
Testing Curiosity on 20 degree slope on
Earth
Curiosity and Mars 2020
Rovers are roving field
geologists
Different toolkits:
Science
Instruments
and Sampling
System
Mars 2020:
Robotic Field
Geologist
+ Astrobiologist
Curiosit
y
Image Credit: NASA/JPL-
Caltech
Image Credit: NASA/JPL-
Caltech

9. 9
Perseverance
Objectives
•Habitability
•Biosignatures
•Sample Caching
•Prepare for Humans
Landed on Mars February 18,
2021 at the site of an ancient
river delta in a lake that once
filled Jezero Crater

10. 10
nSupport Turret-mounted instrument investigations
oAbrade rocks & remove dust
to prepare surfaces for examination
oPosition these instruments
with respect to both the Martian surface
nAcquire and place on the surface of Mars a set of scientifically
selected and documented samples of Martian materials and
standards / blanks adequate to address the mission objectives
What does Sampling &
Caching do?
CT scan of a sealed Sample Tube, the result of a ground-based
end-to-end test
Credit: CT data was captured and post-processed by John Bescup of JPL’s Analysis
and Test Laboratory.)
Sol 160, Mastcam-Z
Image Credit: NASA/JPL-
Caltech
Sample Tube shown in a clean room
on Earth
Image Credit: NASA/JPL-Caltech

11. 11
Drilling and Caching
Animation
https://mars.nasa.gov/mars2020/multimedia/videos/?
v=423

12. 12
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oDEFINE/ARCHITECT
lDefine the “Chunks of the System” & Identify the Challenge Areas
lDistribute Functionality among the “Chunks of the System” & Determine
Approach to Key Requirements
lPerformance & Interface Requirements, Resources (mass, power, volume,
schedule, etc)
lWhat can be done vs. what needs to be invented
oDESIGN
lDevelopment testing – gain understanding & fix problems
lDetails matter
lMargin – force/torque, deployment, mass, volume
lPerformance & Fault Protection (often the design driver)
oFABRICATE/PROCURE/ASSEMBLE/TEST
lQualify, Prove Robustness & Performance, Characterize & fix problems
What does a mechanism engineer
do? 1/2

13. 13

One “MSL-like” Robotic
System on the “Outside”
•Robotic Arm and Turret
One New Robotic System on the
“Inside”
•Adaptive Caching Assembly
Place
Turret
Instrument
s
Abrade/
Remove
Dust
Collect
Core
Seal
Sample
Drop-off
Sample
Store
Sample
Assess
Sample
Samples move from “Outside” to
“Inside” through the Bit Carousel
Store Bits
Exchange
Bits
Manipulate
Tubes
“Outside” = Tube +
Bit
“Inside” =
Tube
Sealed Tubes
out the
bottom
Collect
Regolith
SCS Architecture

14. 14
nWe operate on rocks on Mars!
oDiverse and wide range of mechanical properties
lRotary percussive Corer
oUncertainty / variation in environment (topography)
nWe manipulate things on Mars!
oAutonomous Robotic Interaction
lMechanisms, Electronics, Algorithms, and Software all working together
lMinimal ground in the loop for science throughput
lForce sensing and control is enabling and critical
nWe do it all extremely cleanly on Mars!
oMaintain integrity of the in-situ science and the return samples
Challenges

15. 15
Resources & invented / to be
developed
nResources
o17 actuators, 2 robotic arms, 3 force sensors (multi-axis in both robotic
arms and single axis in the corer), integrated hardware/software
development – just to name a few
nInvented / To Be Developed
oCollect intact cores
oHermetic Sealing
oCleanliness
oForce Sensing

16. 16
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oDEFINE/ARCHITECT
lDefine the “Chunks of the System” & Identify the Challenge Areas
lDistribute Functionality among the “Chunks of the System” & Determine
Approach to Key Requirements
lPerformance & Interface Requirements, Resources (mass, power, volume,
schedule, etc)
lWhat can be done vs. what needs to be invented
oDESIGN
lDevelopment testing – gain understanding & fix problems
lDetails matter
lMargin – force/torque, deployment, mass, volume
lPerformance & Fault Protection (often the design driver)
oFABRICATE/PROCURE/ASSEMBLE/TEST
lQualify, Prove Robustness & Performance, Characterize & fix problems
What does a mechanism engineer
do? 1/2

17. 17

Challenge: We operate on rocks on
Mars! – Development Testing
Collected Sample
External thermal coating
(Aluminum Oxide)
Internal surface treatment
(Ti Nitride)
Mars analog rocks for Earth
testing
Cores made by development test
Corer
Packaged for Earth Return

18. 18
Dirt & Dust Management and
Mitigation – Sampling System
Philosophy
•It starts with understanding there is challenge!
•We operate on rocks on Mars!
•Two sources
•Self-generated dust & dirt from performing our function
•Dusty Mars environment
•Incorporate it into the architecture and design thinking from
the start
•Early development testing to inform/correct our design
thoughts
•And finally testing in an integrated end-to-end operational
environment with flight-like hardware, flight algorithms, and
processes in a simulated Martian environment
•Qualification Model Dirty Test program (QMDT)
•Uncover the need for and develop additional mitigations to
address any issues that arise
From the
identified
challenges list

19. 19
Challenge: We operate on rocks
on Mars! - Architecture & Design
Features
•Architecture
•Multiple bits; Extra Tubes above Sample Return requirement;
More Seals than Tubes
•Design Features – Accommodation for Dust buildup
•ACA station error budgets contain explicit line items for material
buildup
•E.g. Sealing Station, Bit Holders, Sealing (between seal/tube
interface)
•Seals to prevent dust from getting into mechanism components,
e.g. motors, bearings, gears, etc
•Escape paths for generated material; fits to accommodate
material
•Corer Chuck (percussion helps to motivate dirt out), Sealing
Station gripper
•Bit Carousel interior design enables material to work its way to
the lower opening and exit to the Martian surface

20. 20
What is a Mushroom? –
Discovered During
Development Testing
nIn addition to the core, sometimes another rock chunk, nicknamed
a “mushroom,” is produced between the tube shear plane and the
parent rock during the Core Break operation
nMushrooms can get lodged between the bit teeth after tube
extraction, creating a risk to bit reuse in flight
Different break
locations correspond
to different torque
peaks
Shear
Bending
QMDT038 QMDT034 - Mushroom in bit teeth
Example of No mushroom (dev test)
Bending
mushroo
m
Information from Kyle Brown, Corer
CogE

21. 21
Mushrooms – Operational
Mitigations
n“Mushroom” behavior discovered during development
testing
oBit design modifications did not remove mushroom generation but
operational mitigations have been very reliable
o33% of Coring operations generate mushrooms but nearly all are cleared
using the “Percuss to Ingest” operational mitigation. 1.3% of generated
mushrooms remain lodged in the bit (dev test results based on >500
operations)
Percuss to Ingest (PTI)
•Point bit up 45 deg
•Percuss to ingest
mushroom into tube
(eject is ok too)
•Done after every Coring
as part of baseline
operation
Percuss to Dislodge (PTD)
•Insert fresh tube
•Point bit down 45 deg
•Percuss to eject
mushroom
•Success rate: 1/1 in
QMDT (QMDT043)
Drill to Dislodge (DTD)
•Insert fresh tube
•Perform hole start
•Ingest mushroom into
tube
•Not yet attempted in
QMDT
Part of Every Coring
Operation
Used in Subsequent Sols if MastCam image
reveals a mushroom
Information from Kyle Brown, Corer
CogE

22. 22
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oDEFINE/ARCHITECT
lDefine the “Chunks of the System” & Identify the Challenge Areas
lDistribute Functionality among the “Chunks of the System” & Determine
Approach to Key Requirements
lPerformance & Interface Requirements, Resources (mass, power, volume,
schedule, etc)
lWhat can be done vs. what needs to be invented
oDESIGN
lDevelopment testing – gain understanding & fix problems
lDetails matter
lMargin – force/torque, deployment, mass, volume
lPerformance & Fault Protection (often the design driver)
oFABRICATE/PROCURE/ASSEMBLE/ TEST
lQualify, Prove Robustness & Performance, Characterize & fix problems
What does a mechanism engineer
do? 1/2

23. 23
QMDT Venue – End to End “Dirty”
Testing
Looking from
below
ACA
Rock
s
Robotic Arm
Corer/Turr
et
•Low pressure
•-110 to +70 deg C
capability
•Runs flight code/fault
protection using GSE
electronics
•End-to-end sampling and
caching

24. 24
nTurn a function into a robustly implemented
electromechanical device that performs well and integrates
into the rest of the system
oINTEGRATE INTO NEXT LEVEL OF ASSEMBLY/TEST SOME MORE
lQualify, Prove Robustness & Performance, Characterize
lFix problems
oLAUNCH (if you are part of a spacecraft)
oLAND (if you are a Mars Rover)
oOPERATE
lComplex electromechanical devices / subsystems tend to have more
mechanisms engineers from the development cycle during the early part of
operations
lTell the Rover what to do each sol (Martian day)
lAnalyze Rover Health and Performance
lFix problems
What does a mechanism engineer
do? 2/2

25. 25
A historic moment on Mars
https://mars.nasa.gov/mars2020/mission/status/
Sol 194, CacheCam, Image Credit: NASA/JPL-
Caltech
Sol 196, Navcam, Image Credit: NASA/JPL-Caltech
Perseverance Collects, Seals, and Stores its First Two Rock Samples
Sol 193, Mastcam-Z
Image Credit: NASA/JPL-
Caltech/ASU/MSSS
https://mars.nasa.gov/mars2020/news/

26. 26
14 rock cores & their associated
abrasions – as of 11/18/2022
Map Production & Image Credits: NASA/JPL-Caltech/Univ. of
Az/MSSS
Visit mars.nasa.gov/mars-rock-samples/ to see what we have collected since.
Mission total (as of 11/21/2024) 22 rock cores, 2 regolith, 1 atmospheric, 3
witness tubes

27. 27
For more JPL missions…
nVisit the “Mission” area of JPL’s public website,
jpl.nasa.gov
oMissions and instruments built or managed by JPL have visited every
planet in our solar system and the sun and have entered interstellar
space.
oCurrently 40 active missions
nRead about Past, Present, and Future Missions (here are a
few)
oEuropa Clipper – will conduct reconnaissance of Jupiter’s icy moon
Europa and investigate whether it could have conditions suitable for life
lLaunched on October 14, 2024, Arrival at Europa in 2030
oPSYCHE – on its way to a unique metal-rich asteroid Psyche orbiting the
Sun between Mars and Jupiter
lThe asteroid appears to be the exposed nickel-iron core of an early planet
oNISAR – NASA-ISRO Synthetic Aperture Radar, a partnership between
NASA and the Indian Space Research Organization (preparing for a 2025
launch)
lAdvanced radar imaging views of the Earth to understand its processes &
changing climate

28. 28
Dare Mighty Things
Far better it is to dare mighty things, to
win glorious triumphs, even though
checkered by failure ... than to take rank
with those poor spirits who neither enjoy
nor suffer much, because they live in the
gray twilight that knows neither victory
nor defeat.
- Theodore Roosevelt

29. 29
Questions?

30. 30
Backup

31. 31
Checking out the hardware
on Mars
Sol 15, Right Navcam
Image Credit: NASA/JPL-Caltech
Sol 18, Left Navcam
Image Credit: NASA/JPL-Caltech
https://mars.nasa.gov/mars2020/multimedia/raw-
images/

32. 32
Imaging with SHERLOC WATSON on
Mars
https://mars.nasa.gov/mars2020/multimedia/raw-
images/
Sol 78, SHERLOC
WATSON
Image Credit: NASA/JPL-Caltech
Sol 78, Front Left
Hazcam
Image Credit: NASA/JPL-Caltech

33. 33
Robotic Arm / Turret

Place
Turret
Instrument
s
Abrade/
Remove
Dust
Collect
Core
Collect
Regolith
•Robotic Arm positions/preloads
Turret-mounted tools and
instruments
PIXL
SHERLOC
Corer
Facility
Contact
Sensor
gDRT

34. 34
Surface Preparation & Sample
Acquisition

Coring Bit
Abrading Bit
Launch
Abrading Bit
Regolith Bit
Developmen
t Bit
Assemblies
Regolith Weakly Consolidated Rock Moderately Consolidated
Rock
Well Consolidated Rock Hard Rock

35. 35
Sample
Tube
Storage
(39 Places)
Bit
Carousel
Tube, Glove,
& Cover Drop-
off Station
Cover
Parking
Lot
Sealing
Station
Cover
Parking Lot
(spare)
Vision
Station
Hermetic
Seal
Dispenser
(7 Places)
Sample
Tube
Storage
(4 Places)
Sample Handling
Assembly (SHA)
3 dof (z + 2
planar)
Volume
Assessment
End Effector
Caching
Component
Mounting Deck
(CCMD)
Adaptive Caching Assembly
- Robotics on the “Inside’

+Z
+Y
+X
Rover
Coordinate
System
Seal
Sample
Drop-off
Sample
Store
Sample
Assess
Sample
Store Bits
Manipulate
Tubes
Single Sample Handling Arm to
access individual stations:
Bit carousel, tube storage, hermetic
seal dispensers, vision assessment,
volume assessment, cover parking lot,
sealing, passive drop-off

36. 36
Challenge: We manipulate things
on Mars! RCCM and SHA
Operations

Z
X
Y
Twist
TipTilt
Lateral – XY plane
Angular – XY
Tip/Tilt
Clocking – Z Twist
SHA
RCCM
Glove
Tube
End Effector
3 degree-of-freedom SHA
•2 rotary joints for X-Y planar
motion
•1 linear stage for Z motion
SHA positions the end effector
and supplies the forces
necessary to perform the task
at each station
RCCM passively complies to angular,
lateral and clocking misalignment
during SHA interaction with 8 unique
ACA stations
Composite Beam
6 axis
Force sensor
Tube Gripper
Assy

37. 37
Challenge: We manipulate things on
Mars! Force Sensing Enables SCS
Functions

•Force sensing is critical for many SCS
functions
–All force sensors are single channel fault
tolerant
•Using the force sensor for relative
measurement allows for significant reduction
in error sources in the transducer and read
circuit
•In some cases, sensors are used in absolute
mode for fault protection
(inside
turret spool)
SCS Force Control Modes (implemented in RCE FSW)
Name Description SCS Applications
Force Nulling
Force-torque sensor reading to
derive a multi-joint position move to
zero-out force and moments
•RA Ground Force Nulling
•Docking
•SHA Preloading (lateral)
Load Limiting
Stop motion when force threshold
has been passed
•Inadvertent contact of RA,
Turret and SHA
Load
Application
Apply a desired static load
•RA preload: Ground &
Dock
•Corer WOB
•SHA Preload (Fz)
WOB
Maintenance
Only active control case. Same as to
MSL. Feed rate adjusted based on
force signal error.
•Coring
•Bit Exchange

38. 38
Robustness Testing for Dusty
Mars
•Rover external ACA mechanisms tested to
assess robustness to dust
–Bit Carousel docking assembly
•Dust exposure during landing event as well as
Mars surface operations
•Dust chamber used to expose hardware to
extreme dust event
–Bit Carousel upper door release mechanism
•Dust exposure during landing event
Dust Chamber with circulating fans
After Dust Accumulation After tilting the hardware
vertical and setting back
down horizontal.
*TEST CONDITION*
Upper Bit Carousel Door release when exposed to dirt
Post Test Drag measurements still
have good margin to function