Mars Sample Return Campaign Concept Architecture

Mars Sample Return Campaign Concept Architecture
A White Paper for the Planetary Science and Astrobiology Decadal Survey 2023-2032
Primary Author: Brian K. Muirhead, brian.k.muirhead@jpl.nasa.gov, phone: (818) 687-7003.
Jet Propulsion Laboratory, California Institute of Technology
4800 Oak Grove Drive, Pasadena, CA 91109
Co-Authors:
Austin K. Nicholasa, austin.k.nicholas@jpl.nasa.gov
Chad Edwardsa, charles.d.edwards@jpl.nasa.gov
Jeffrey Umlanda, jwumland@jpl.nasa.gov
Sanjay Vijendranb, vijendran@esa.int
Richard Zureka, richard.w.zurek@jpl.nasa.gov
aJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA
b
European Space Agency, Noordwijk, The Netherlands
Executive Summary
The Planetary Science and Astrobiology Decadal Survey 2023-2032 (hereafter the Survey) has
been asked by NASA to assess whether the Agency's "plans for Mars Sample Return (MSR) play
an appropriate role in the research strategy for the next decade". This white paper provides an
overview of the campaign concept architecture.
MSR is currently envisioned to be a campaign of three flight elements and one ground element.
The Mars 2020 mission with its Perserverance caching rover is the first element and is on schedule
to launch this July. This paper describes the other two flight elements envisioned for MSR, namely
a Sample Return Lander and Earth Return Orbiter, that are being jointly studied by NASA and theEuropean Space Agency (ESA). Overall objectives and mission options will be described,
including the campaign architecture’s constraints and notional timelines. The paper will highlightarchitecture-level trade studies and their current status as part of the reference architecture
proceeding toward possible project approval to enter Phase A.
The MSR campaign architecture is well understood, with major progress on the technical trades
and key technology developments. NASA and ESA are working together well in an effective
partnership, with roles and responsibilities in place and operating.
With this study phase at a very mature state, preparations are being made for a MSR Campaign
Concept Review in late summer 2020, as part of the process by which NASA will decide whether
MSR is ready to proceed into formulation. ESA has already received approval, at their ministerial
level, to proceed forward with their part of the program.
Keywords (acronyms): Mars Sample Return (MSR), Sample Retrieval Lander (SRL), Sample
Fetch Rover (SFR), Mars Ascent Vehicle (MAV), Orbiting Sample (OS) container,
Capture/Containment and Return System (CCRS), Earth Return Orbiter (ERO), Earth Entry
System (EES)
Acknowledgment: Part of this work was carried out at the Jet Propulsion Laboratory, California
Institute of Technology, under contract with the National Aeronautics and Space Administration.

Predecisional information, for planning and discussion only

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1. Introduction
The previous planetary decadal survey report[1] Visions and Voyages for Planetary Sciencein the Decade 2013-2022 (hereafter V&V2011)
recommended, as its highest-priority flagshipmission for the decade, the Mars Astrobiology
Explorer-Cacher (MAX-C) to begin a NASAESA Mars Sample Return campaign. In that
scenario, MAX-C was a caching rover to be
jointly landed with the ExoMars rover. Due tothe complexity and cost of landing two
substantial, independently designed rovers witha single landing system, these two rovers were
ultimately separated, and MAX-C became asingle rover, the Mars 2020 rover, with a majoremphasis on in situ science, but also with thecapability to cache samples, whose means andschedule of return were left for future
definition.
That changed with a presentation from theNASA Associate Administrator, Dr. Thomas
Zurbuchen, to the National Academies on
August 28, 2017 [2]. Mindful of V&V2011's
recommendation that such an ambitious
enterprise must also involve ESA participation,
NASA and ESA officially began a newcollaboration with a joint NASA/ESA
Statement of Intent (signed in Berlin on
4/26/18). Earlier scenarios of this architecture
and its concepts for an MSR campaign havebeen presented at various international forums
including the Second International Mars
Sample Return Conference in April 2018, in
Berlin and the International Astronautics
Congress in Oct. 2018 in Bremen.
As recognized in V&V2011, the Mars
science community continues to see a sample
return mission as the logical next step in Mars
exploration. The international MSR Objectives
and Samples Team (iMOST) re-evaluated andupdated the sample-related science andengineering objectives of a MSR campaign [3].
As described in the companion white paper [4],that team found that the samples to be preparedby the Mars 2020 rover at its Jezero Crater
landing site would address compelling science
questions of habitability (pre-biotic chemistry
Predecisional information, for planning and discussion only

and possible biology) and planetary evolution(of atmospheres, surface and crusts), not only
for Mars, but for the Solar System.
V&V2011 (p. 270) fully recognized that theircommittee had recommended a plan for theircoming decade that "also had signficant budget
implications for one or even two decades
beyond". They also recognized (p. 276) there
had to be "significant technology investments in
the Mars Sample Retrieval Lander [and] Mars
Sample Return Orbiter..." to mature key
technologies and to reduce costs and risks. In
the years since, NASA and ESA have madesignificant investments that have yielded theoverall campaign architecture, mission
concepts, and maturation of key technologies
described here.
2. Planning for a Mars Sample Return
Campaign
2.1 MSR Conceptual Architecture
MSR is currently envisioned to be made upof three flight elements and one groundelement. This is the same (with slightly
different nomenclature) as the mission
architecture evaluated in V&V2011: 1) A
caching rover, now the Mars 2020
Perseverance, 2) a Sample Retreival Lander(SRL), and 3) an Earth Return Orbiter (ERO).
The ground element would be a Mars
Returned Sample Handling (MRSH) facility,with international governance, that will be
discussed in a subsequent white paper.
Mars 2020 Perserverance is responsible forsample selection, context characterization,acquisition and caching. Ready for launch inJuly 2020, it will land in February 2021 inJezero Crater, a site selected after 4 years ofstudy and discussion of extensive remotesensing data.
The next flight elements are the SRL which
would carry: a) a Sample Fetch Rover (SFR) to
retrieve the cached samples for placement in the
Orbiting Sample (OS) container, and b) a Mars
Ascent Vehicle (MAV) to launch the OS into
Mars orbit. A sample transfer arm (STA) will

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robtotically transfer the sample tubes from thefetch rover into the OS. The ERO would carry
the Capture/Containment and Return System(CCRS), which would capture and contain the
OS breaking the chain of back contamination.
The OS is then placed into an Earth Entry
System (EES) which the ERO releases near
Earth for eventual return to the surface.
2.2 Functional Objectives
The campaign functional objectives for the
next flight elements in a potential NASA/ESAMSR joint campaign are:
• Retrieve and return to Earth a scientificallyselected set of Mars samples forinvestigation in terrestrial laboratories,
thereby achieving a set of sample-relatedscientific objectives addressing life,
geologic environments, geochronology,
volatiles, environmental hazards, and InSitu Resource Utilization (ISRU).
• Ensure the scientific integrity of the
returned samples through contamination
control (including round-trip Earthcontamination and sample-to-sample crosscontamination) and control of environments
experienced by the samples after acquisition.
• Ensurecompliancewithplanetary
protection (PP) requirements associatedwith the return of Mars samples to Earth’s
biosphere.
2.3 NASA/ESA Roles in MSR
The joint NASA/ESA Statement of Intent
has divided the project responsibilities asfollows: NASA would have overall campaign
responsibility and would provide the SRL andthe MAV, the CCRS including the Earth Entry
System (EES), which the ERO would carry.
The ERO itself and the SFR would be provided
by ESA. ESA would also provide the Sample
Transfer Arm on the NASA provided SRL.
2.4 Operations Timeline Concept for Arrival
The latest conceptual MSR campaign
timeline proposes a 2026 launch which could
Predecisional information, for planning and discussion only

return samples as soon as 2031. [3] The
notional timeline has four essential features:• After an extended cruise, SRL would arriveat the beginning of northern spring at a timeof seasonally high atmospheric pressure
which would improve entry/descent/landing(EDL) performance and thus mass margin.
• Arrival at that time followed by launch of
the MAV before Northern Fall enables asolar-power-only mission during the Marsseasons of lowest atmospheric dust opacity.
• After a later launch than the SRL but on ashorter cruise, the ERO has time to sprial
down into low Mars orbit, enabling telecom
coverage of SRL EDL and full relay support
for surface operations for both SRL andSFR.
• SRL and ERO trajectories are feasible andfit into available launch vehicle options.
2.5 Backward Planetary Protection
The return of samples from Mars to Earthrequires a Planetary Protection Categorization
V, with restricted return, which is a requirement
to prevent uncontained or unsterilized material
from Mars from being released into Earth’s
biosphere. This drives the design of MSR
systems to return the Mars sample tubes in the
OS to Earth, while containing, immobilizing
and/or sterilizing any other Mars material that
the MSR elements may have contacted.
The methodologies used to achieve this arereferred to as “Break-the-Chain,” (of contact
with Mars). The key elements of this "Breakthe-Chain" strategy include [5]:• Establishing design, test and verification
goals and requirements;• Use of various modeling tools, including
fault trees to analyze performance andfailure modes as part of the design process;• Analysis of dust transport mechanisms andmitigations;• Containment techniques;• Sterilization Methodologies and modalities;• Model validation testing.

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2.6 Key Trade Studies and Systems Engineering
The systems engineering team has developed
trade studies while assessing options to achieve
the most robust overall architecture for the
campaign lifecycle as judged by:• Campaign-level mission success;• Number of sample tubes returned to Earth;• Development and operational risk;• Implementation approach;• Cost.
Key metrics being used within the trade spaceand between the elements are:
•
•
•
•
•
•

Mass and power, and associated margins;
Schedule margin (development);
Timeline margin, including overall orbitaland surface operations timeline;
Planetary protection metrics (e.g. dust andparticle reduction factors, containment
element performance);
EDL performance and margins, including
landing accuracy, for both SRL and EES;
MAV and ERO rendezvous and capture
performance and margins.

Figure 1: Propulsive Platform Lander Concept
Mars Science Laboratory and Mars 2020
upgrades, including terrain relative navigation(TRN). SRL is using TRN to enable anextended divert capability that will allow
landing within 20 meters of the desired target.
Figure 2: Skycrane Delivered Lander Concept

3. Lander Concepts Under Study
The multi-center (JPL, MSFC, LaRC, andARC) and international team working on the
MSR SRL have studied two lander concepts: a
Propulsive Platform Lander (PPL, Fig. 1) and a
Sky-Crane Delivered Lander (SDL, Fig.
2). The SRL must land on Mars, deploy the
SFR, and maintain the lander and the MAV(provided by MSFC) within safe operating
conditions, including temperatures, while the
SFR retrieves the M2020 sample tubes.
If still operating, Perserverance may alsodeliver sample tubes to the SRL. Once either orboth of the rovers arrive with sample tubes, theSample Transfer Arm (STA) transfers the tubes
into the OS in the MAV payload area. The SRL
then prepares to launch the MAV (heating it tothe operational temperature and erecting it).
The EDL technology proposed for both
SRL options is mostly common and is based on

Predecisional information, for planning and discussion only

The major lander design drivers areaccommodation of both the MAV (400-500 kg
with margin) and its launch system, and theSFR (200-230 kg with margin) and its egresssystem (provided by NASA).
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The solar power system and thermal design
are being developed for the worst-caseenvironments, which are relatively benign at thenorthern hemisphere Jezero site given arrival inMars spring and launch of the MAV before fall.

Figure 3: Sample Transfer Arm transferring
sample tubes from SFR to MAV OS on SRL.
For cruise, the spinning cruise stage andbackshell are based on MSL designs. Bothconcepts utilize a 4.7-m spherical heatshield(different from sphere-cone used on MSL and
M2020) to improve EDL performance and gain
greater volume for packaging the lander.
The PPL concept employs a propulsion
system similar to Viking, Phoenix or Insight,
with descent and landing thrusters as part of theplatform itself. The current strategy is to use
six M2020 engines with the standard nozzle andfour engines with showerhead-type nozzles forterminal descent, to reduce plume interaction
with the surface. This concept provides larger
configuration and packaging flexibility/margin(in both volume and mass).
The SDL concept provides a softer landing
with less plume/ground interactions due to theSkycrane technology. However, the need toaccommodate the MAV and SFR, as well as
additional propellant for extended divert,
results in significant mass margin andpackaging volume problems for the SDL.
Based on results from the architecture
closure process, the PPL was selected as thereference baseline.
Predecisional information, for planning and discussion only

4. Orbiting Sample (OS) Container, MAV
Payload Assembly (MPA) and Sample
Transfer Arm (STA)The OS must hold the desired number of sample
tubes as retrieved by the SFR and/or Mars 2020.
The final number of tubes remains a parameter
under study but the system has been designed tocarry 30 tubes. The shape of the OS has been
designed to be cylindrical with rounded caps tomaximize the number of tubes at the lowest
possible mass. Tubes would be inserted fromthe SFR storage rack into the OS by the STA on
the lander (Fig. 3). A different technique using
the same transfer arm, now equipped with a"catcher's mitt", could be used to transfer tubes
still to be dropped by Perseverance .
After the OS has been filled, it would beclosed and sealed (using an engineered lip seal),
and the MPA cover closed for launch. The
tubes need to be secured and maintained
through environmental conditions throughMars launch, Earth return and Earth landing.
Constraints placed on the management of thesample tubes by science include maintaining thetemperature to less than +30 ºC and magnetic
field below ½ mT (at the sample). Additionally,
the OS must have sufficient albedo (assumed>0.7) to be detected in Mars orbit by visible
light framing cameras on the ERO.
5. Mars Ascent Vehicle (MAV) Concept
The MAV performance and reliability(including launch mass and injection into orbit)
was evaluated by MSFC and JPL for two
propulsion technologies, a single stage to orbit
hybrid (solid fuel/liquid oxidizer) or a two-stage
solid (Fig. 4). The MAV would be responsible
for launching the OS from the surface of Mars
into a nearly circular orbit of ~400 km altitude
and 25 degree inclination.
The drivers for the MAV are its mass andsize (~3 m long by 0.57 m diameter), as bothmust be accommodated in the previously
described lander.

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Preparation (MREP) Program, such as visual
odometry, miniaturised avionics, and low
temperature mechanisms and batteries.
The current concept would use wheels
provided by NASA-GRC based on a compliant
wheel technology, using a shape memory alloytire, that has been shown to provide exceptional
traversability performance.
NASA and ESA are working to establish
sound interfaces between SFR and the lander,
based on a top mounted SFR with NASA
providing the egress system.
Figure 4: Solid (left) and Hybrid (right) MAV
Concepts
The hybrid single-stage-to-orbit propulsion
system uses a wax-based fuel and Mixed
Oxides of Nitrogen (MON) oxidizer capable ofbeing stored in the variable and low temperature
conditions on Mars. [6]The solid design would use an updated low
temperature propellant previously used on theMars Pathfinder and Mars Exploration Rovers
Rocket Assisted Deceleration systems.
Based on comparable performance but therelative maturity of the solid motor technology,
the solid MAV was selected as the reference
baseline.

7. Earth Return Orbiter (ERO) Concept
The ESA Earth Return Orbiter (Fig. 5)functions include: 1) providing the launch andpropulsion energy needed to meet the round-trip
missiontimeline;2)
providingthetelecommunications relay function needed by
the surface mission, including EDL;
3) executing the autonomous rendezvous andcapture in Mars orbit of the OS with its samples;and 4) returning to Earth and achieving
targeting for release of the EES.

6. Sample Fetch Rover (SFR) Concept
ESA has selected Airbus Defense and Space
UK to develop the Sample Fetch Rover (SFR)
as a possible contribution to the Mars Sample
Return Campaign. Airbus is currently working
with JPL to define requirements and interfacesthat will allow the development of a breadboard
to demonstrate in a field trial the end-to-end
operational concept, including the capability totraverse autonomously and pick up and store thesample tubes for transport back to the SRL.
The SFR concept is a four-wheel vehicle
with ExoMars heritage for the locomotion
system elements, thermal control and energy
management, and autonomous navigation. SFR
is also incorporating technologies developed
through the ESA Mars Robotic Exploration

Predecisional information, for planning and discussion only

Figure 5: Earth Return Orbiter (ERO) Concept
ESA has selected the ERO contractor,
Airbus Toulouse, who developed Bepi
Columbo, to accommodate the NASA-provided
CCRS, all to be launched on an Ariane 6.4. The
ERO will use a hybrid chemical and electrical
propulsion system that would provide the firstroundtrip trajectory between Eath and Mars.

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8. Capture/Containment and Return System(CCRS)
The current CCRS concept is comprised ofthree major elements (Fig. 6). The Capture,
Orient Module (COM) would capture, secure,orient the OS and then transfer it to theContainment Module (CM) to complete the firstcontainment stage by encapsulating the OS in a
primary containment vessel which by design“Breaks the Chain” of contact with Mars. A
robotic arm transfers the encapsulated OS to theEES, installs a secondary containment vessel
lid, and completes the closure by installing thebackshell cover. To save mass, the COM/CM
are jettisoned before leaving Mars orbit.

Figure 6: Capture/Containment and Return
System (CCRS) Concept
The EES (shown in Fig. 6) is being designed
consistent with past interplanetary Earth entry
vehicles including an entry velocity of <12km/s. The EES is a fully passive aerodynamic
design for entry and landing without use of aparachute, driven by the high reliability needed
to meet Backward Planetary Protection
objectives.
The EES is being designed tosustain the OS and sample tube integrity uponlanding with a nominal landing load <1300 g’s
and an off-nominal hard surface landing load
<3000 g’s.
9. Summary
The Mars Sample Return campaign design
studies at NASA and ESA are proceeding well.
The MSR campaign study process has

Predecisional information, for planning and discussion only

established a reference baseline that has closed
on a robust campaign architecture inpreparation for a MSR Campaign Concept
Review in late summer 2020. NASA and ESA
are working together well in an effective
partnership, with roles and responsibilities
clearly defined and being implemented.
Acknowledgements
The information about a potential Mars
Sample Return campaign is pre-decisional andis provided for planning and discussion
purposes only. Some of the work reported here
was carried out at the Jet Propulsion
Laboratory, California Institute of Technology,
under a contract with the National Aeronautics
and Space Administration.
References[1] NRC (2011), Vision and Voyages forPlanetary Science in the Decade 20132022,
National
Academies
Press,
Washington DC, ISBN: 0-309-20955-2.
[2] T. H. Zurbuchen, Mars Exploration
Program, Presentation to the National
Academies, 28 Aug 2017.
[3] iMOST (2018), The Potential Science andEngineering Value of Samples Delivered
to Earth by Mars Sample Return,
Meteoritics & Planetary Science(https://onlinelibrary.wiley.com/doi/epdf/1
0.1111/maps.13242).
[4] H. Y. McSween, M. M. Grady et al., "WhyMars Sample Return is a Mission
Campaign of Compelling Importance toPlanetary Science and Exploration," White
Paper for the Survey, 2020.
[5] Robert Gershman, et al. “Break-theChain Technology for Potential Mars
Sample Return,” IEEE Aerospace Conf.,
2018, Big Sky, Montana, March, 2018.
[6] Ashley C. Karp, et al., “Technology
Development for a Potential Hybrid Mars
Ascent Vehicle," International
Astronautical Congress, Bremen,
Germany, Oct. 2018.

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