Mars Ascent Vehicle Study Summary: Potential Mars Sample Return Campaign; Assumptions; Motor Sizing; Propellant Selection; Nozzle and Controls; Development and Qualification Testing; Future Work

Kibbey, Timothy

McCauley, Rachel

McCollum, Lisa

Oglesby, Britt

Prince, Andrew

Stenfanski, Philip

NASA Technical Reports Server

www.jpl.nasa.gov
Mars
Ascent
Vehicle
Mars Ascent Vehicle Propulsion System Solid Motor Technology Plans
Andrew Prince / MAV Solid Propulsion Lead, NASA MSFC
March/2019
https://ntrs.nasa.gov/search.jsp?R=20190002134 2019-08-30T22:50:22+00:00Z
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 2
Mars Ascent Vehicle Study
Summary
• Co-authors: Rachel McCauley, Timothy Kibbey, Lisa McCollum, Britt Oglesby, Philip Stenfanski
• Potential Mars Sample Return Campaign
• Assumptions
• Motor Sizing
• Propellant Selection
• Nozzle and Controls
• Development and Qualification Testing
• Future Work
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 3
Mars Ascent Vehicle Study
Potential Mars Sample Return Campaign
• Mars 2020 rover
• Collect and cache samples
• Earth Return Orbiter (ERO)
• Enter Mars orbit ready to receive 
samples and transport back to 
earth
• Sample Retrieval Lander
• Places Mars Ascent Vehicle 
(MAV) on Mars for sample stow 
and launch to ERO
Sample Retrieval
Lander (SRL)
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 4
Mars Ascent Vehicle Study
MAV Propulsion
• Currently MAV is trading between hybrid and solid propulsion with a selection to be made in 
September 2019
• This presentation is about the methodologies and progress toward developing the solid 
propulsion vehicle
MAV Concept History
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 5
Mars Ascent Vehicle Study
Ground Rules and Assumptions
• Mass, length and diameter are driven by the lander
• Length is shared with payload, avionics and Reaction 
Control System (RCS)
• Landing site selection will affect low temperature 
requirements
• Maximum shock will be parachute snap
Assumption Value
Maximum GLOM (kg) 400.0
Maximum Vehicle Length (m) 3.0
Vehicle Diameter (m) 0.57
Payload Length Length (m) 0.5
Altitude (m) 343,000.0
Maximum Angle of Attack (degrees) 4.0
Launch PBMT (C) -20 (+/-2)
Storage Temperature Min/Max (C) -70/40
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 6
Mars Ascent Vehicle Study
Design Methodology
• First Stage: High initial thrust to overcome gravity losses; Burn time and throttling to 
minimize max Q (Boost-Sustain)
• Second Stage: Insensitive to burn time variation; Sensitive to Isp variation
0 20 40 60 80 100
D
yn
am
ic
 P
re
ss
u
re
Mission Time, sec
Motor burnout
Mission Flight Profile First Stage Dynamic Pressure
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 7
Mars Ascent Vehicle Study
Propellant Mass Fraction Model
• A non-dimensional relationship was derived for propellant mass fraction (pmf)
• Like sized motors were surveyed based on pmf and propellant mass
• A subset of boost-sustain motors yields a slightly lower curve due to added insulation for the 
longer burn times
• Where,
• = minimum inert mass or the limit as propellant goes to infinity
• = slope of data
• = a reference propellant mass driving the location of inflection 0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
0.1 1 10 100 1000 10000
pr
op
el
la
nt
 m
as
s f
ra
ct
io
n
propellant mass, kg
Boost-Sustain 
Motor, no TVC
Nearby TVC 
motor
Like Upper Stage 
motors, no TVC
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 8
Mars Ascent Vehicle Study
MAV Motor Model
• Modification to the pmf model were made to account for 
MAV specifics
• Additional interstage structures were accounted for by 
assuming 10% propellant offload
• A 25% MGA assumed for the second stage
• Additional inert mass added to the larger first stage for 
increased TVC
• The first stage is similar to a commercially available 
system allowing a 15% MGA to be assumed
0.75
0.8
0.85
0.9
0.95
25 250
pr
op
el
la
nt
 m
as
s f
ra
ct
io
n
propellant mass, kg
Stage 2 w/ Offload, 25%MGA
Stage 1 w/ TVC, 15% MGA
Space Motors
10% offload 
25% MGA
Addition of TVC, 
plus 15% MGA
First and Second Stage Adjusted Trends
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 9
Mars Ascent Vehicle Study
Motor Sizing
• Modified COTS solution: 
• Minimize Gross Lift Off Mass (GLOM)
• Isp assigned to each motor based on Commercial Off 
The Shelf (COTS) motors and 3 DOF analysis
• Propellant mass allowed to vary to meet orbital 
assumptions while minimizing GLOM 
• Optimum solution:
• GLOM limited to 400 kg
• Isp allowed to move along trend as required to meet 
orbital assumptions
y = 11.766ln(x) + 241.81
280
285
290
295
300
305
20 200
Isp
, s
Expansion Ratio
Isp of COTS Products
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 10
Mars Ascent Vehicle Study
Thrust Traces for Both Solutions
• The optimum solution requires challenging Isp values 
that are above the trend of other COTS products
Parameter GLOM, kg
Stage 1 2
Modified COTS 288 291 419
Optimum 300 293 399
Isp, sec
0 10 20 30 40 50 60 70 80
Ef
fe
ct
iv
e 
Sp
ec
ifi
c 
Im
pu
ls
e
Diameter, cm
Proposed MAV First Stage
COTS Isp vs. Diameter Modified COTS Optimum
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 11
Mars Ascent Vehicle Study
Propellant Selection
• A set of COTS propellants were surveyed based on a set of specific assumption
• -70 ºC/ +40 ºC storage and -20 ºC Operation
• Ranked density-impulse
• Effects of Planetary Protection procedures
• Bio-reduction (heat or radiation)
• Bio-barriers
• End-of-mission procedures
• TRL level – Similar mission histories
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 12
Mars Ascent Vehicle Study
Nozzle and Controls
• With low operational temperature assumptions freezing slag is concern
• Subsonic splitline vectorable nozzle could get entrained with slag and freeze up
• Therefore a super sonic splitline was selected
• RCS sizing will rely on 6 DOF results when received
• Cold gas vs hydrazine
• Minimize mass
• Favors minimal Q at first stage burnout
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 13
Mars Ascent Vehicle Study
Development and Qualification Testing Planning
• Defining a development/qualification is important for planning purposes
• More motors can reduce risk and increase cost requiring these to be balanced
• A qualitative matrix of risk with varied numbers of motors was derived based or assumption 
parameters qualified
• A set of 3 development and 3 qualification motors were selected by the project
• Flight test is considered a qualification motor in Dev/Qual Plan
Stage 1 Stage 2
Development 3 3
Qualification 3 3
Flight Test 1 1
Inert Mass Simulator 1 1
Flight 2 2
Total Motors 10 10
SUB-SCALE TESTING
PLANETARY 
PROTECTION
THERMAL 
CYCLING COLD-SOAK
PLANETARY 
PROTECTION
THERMAL 
CYCLING COLD-SOAK
FLIGHT TEST OR 
FLIGHT-LIKE TEST
1 X X X 3 DMs + 8 QMs 3 DMs + 8 QMs 3 DMs + 8 QMs 5 QMs 1X2 3
2 2X 2X 2X 3 DMs + 6 QMs 3 DMs + 6 QMs 3 DMs + 6 QMs 4 QMs 2X2 6
3 3X 3X 3X 3 DMs + 4 QMs 3 DMs + 4 QMs 3 DMs + 4 QMs 3 QMs 3X2 9
4 X X X 3 DMs + 4 QMs 3 DMs + 4 QMs 3 DMs + 4 QMs 3 QMs 3X2 9
5 2X 2X 2X 3 DMs + 3 QMs 3 DMs + 3 QMs 3 DMs + 3 QMs 2 QMs 2X3 11
6 3X 3X 3X 2 DMs + 2 QMs 2 DMs + 2 QMs 2 DMs + 2 QMs 1 QM 2X4 14
OPTION FINAL RISK SCORE
FULL-SCALE TESTING LIKELIHOOD                    
X                  
CONSEQUENCE
Dev/Qual Plan
Dev/Qual Risk Matrix
For More Information, Contact: andrew.s.prince@nasa.gov
National Aeronautics and Space Administration
Jet Propulsion Laboratory / Marshall Space Flight Center
March 2019 - 14
Mars Ascent Vehicle Study
Future Work
• Refine and iterate with other subsystems
• Trade Isp (expansion ratio) with vehicle 
mass (interstage)
• Trade aero stability with flow feature 
mass and location and design
• Refine design models (CAD) for minimum 
mass Current MAV Solid Vehicle Concept


Mars Ascent Vehicle Propulsion System Solid Motor Technology Plans

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