Describes concept of the Fission Fragment Rocket Engine (FFRE)

Clark, Rod

Percy, Thomas

Sheldon, Robert

Werka, Robert O.

NASA Technical Reports Server

2012 Advanced Space 
Propulsion Workshop 
 
FFRE  Powered 
Spacecraft 
28November 2012 
Robert O. Werka, PI, MSFC  EV72, NIAC Fellow 
 Rod Clark, Grassmere Dynamics 
 Dr. Rob Sheldon, FFRE Consultant 
 Tom Percy, MSFC ED04, SAIC 
A program to support early studies of innovative, yet credible visionary 
concepts that could one day “change the possible” in aerospace 
NASA Innovative Advanced Concepts 
https://ntrs.nasa.gov/search.jsp?R=20130001841 2019-08-30T23:40:00+00:00Z
Exploration Technology Today 
An Analogy 
Launch 
Staging 
Burnout 
Safely Home! 
Exploration Technology Today 
An Analogy 
Launch 
Staging 
Burnout 
Safely Home! 
Exploration Technology Today 
An Analogy 
Launch 
Staging 
Burnout 
Safely Home! 
Exploration Technology Today 
An Analogy 
Launch 
Staging 
Burnout 
Safely Home! 
Who Would Want To Explore Like This? Why Would You Want To Explore Like This? 
The Reason Why 
Because 
That’s The 
Best We 
Can Do 
Now 
AEROSPACEM ar ch  2012
REAL
ESTATE
IN
FREQUENCY
SPACE
A M E R I C A
Viewpoint
The ephemeral
’advanced 
propulsion’
New technologies with the promise 
of more affordable, more efficient, 
and safer propulsion for space 
launch currently seem to be out of 
reach.  That however, does not mean 
that we should stop searching
. . . . . . .All in all, the 
near-to-midterm 
prospects for applying 
„advanced propulsion‟ 
to create a new era of 
space exploration are 
not very good. . . 
by Jerry Grey
Editor-at-Large
24 A E R O S P A C E  A M E R I C A / M A R C H  2 0 1 2
“. . . .  All in all, 
the near-to-
medium 
prospects for 
applying 
„advanced 
propulsion‟ to 
create a new era 
of s ace 
exploratio  re 
not very good. “ 
The Reason Why 
Because 
That’s The 
Best We 
Can Do 
Now 
AEROSPACEM ar ch  2012
REAL
ESTATE
IN
FREQUENCY
SPACE
A M E R I C A
Viewpoint
The ephemeral
’advanced 
propulsion’
New technologies with the promise 
of more affordable, more efficient, 
and safer propulsion for space 
launch currently seem to be out of 
reach.  That however, does not mean 
that we should stop searching
. . . . . . .All in all, the 
near-to-midterm 
prospects for applying 
„advanced propulsion‟ 
to create a new era of 
space exploration are 
not very good. . . 
by Jerry Grey
Editor-at-Large
24 A E R O S P A C E  A M E R I C A / M A R C H  2 0 1 2
“. . . .  All in all, 
the near-to-
medium 
prospects for 
applying 
„advanced 
propulsion‟ to 
create a new era 
of s ace 
exploratio  re 
not very good. “ 
A FISSION FRAGMENT ROCKET ENGINE: 
Engine Attributes: 
 Far Less Propellant Than 
Chemical Or Nuclear Thermal 
(Isp~500,000s) 
 Far More Efficient Than 
Nuclear Electric (100X Thrust) 
 Far Safer Than Nuclear 
Thermal (Charge Reactor In 
Orbit, Radiation Leaves Solar 
System At >1% Light Speed) 
Spacecraft Impact: 
 More Payload 
 Faster Travel 
 Unlimited Electrical Power 
 Enhanced Astronaut Safety 
The Reason Why And An Answer 
Fission Fragment Thrust at 1.7% Light Speed 
Principles of FFRE 
 Reactor Core Uses Submicron Uranium Dust Grains  
 Fissioning Low-Density Dust Is Radiatively Cooled. 
 Moderator Reflects Neutrons To Keep Dust Critical 
 Carbon-Carbon Heat Shield Reflects IR Away From The Moderator. 
 Superconducting Magnets Direct FFs Out Of Reactor.   
 Electricity Is Generated From Heat Shield Coolant 
 Reactor Hole Provides: Heat Escape, FF Escape At 1.7% Light-Speed 
 
FFRE History 
Dusty Plasma FFRE Creation
3D Simulation Of Tokomak 
Nuclear Fusion Reactor 
Magnetically Confined Plasma 
Using Grassmere Code
• Engineering & Consulting
• 40 Years Of Combined Experience In 
Engineering Design, Materials, 
Testing & Quality Assurance.
• Specialty Modeling Skills:
• Computational Fluid Dynamics (CFD)
• Magneto Hydrodynamic Plasma (MHD)
• Nuclear  (Radiation, Reactor Design & 
Performance) 
• Optical
The CompanyGrassmer  Dynamics, LLC
Organize:
Study structure, goals, 
objectives
Identify SMEs, allocate 
resources
Identify study outputs & 
milestones
Notional 
Architecture 
L1 Reqmts
FFRE 
Concept
Spacecraft 
Concept
Iterate to 
Close
Data Archival & Reporting
TRL Maturation 
Roadmap
Operations 
Concept
Test 
Methodology
Manufacture, Technology, 
Issues & Risks
Study Approach 
Study Groundrules 
Attributes: 
 Ellipsoid 
Moderator 
 Ring Magnets 
Assessment: 
 Reduced heat load 
so less Spacecraft 
radiator mass 
 Complex Shape 
Moderator 
 Thrust & Isp 
unchanged 
Generation 1 
Generation 2 Attributes: 
 Dual 
Paraboloid 
Moderator 
 Ring Magnets 
Assessment: 
 Reduced heat                                            
load so less                                            
Spacecraft                                                
radiator mass 
 Complex shape moderator, difficult                             
to support & cool, weighs more 
 Thrust: 2X (86 N, 19 lbf) 
 Isp unchanged (527,000 s) 
FFRE Design Status 
Distribution (MW)
Total Reactor Power 1,000
Neutrons (30% to FFRE) 24.2
Gammas (5% to FFRE) 95.6
Other 70.2
Thermal (IR) 699
Jet Power 111
Performance
Thrust 43 N (9.7 lbf)
Exit Velocity 5170 km/s
Specific Impulse 527,000 s
Mass Flow 0.008 gm/s
FFRE System Total, mT 113.4
Nozzle 6.4
Magnetic Mirror 28.6
Exit Field Coil 11.1
Moderator 51.2
Moderator Heat Shield 0.1
Control Drum System 0.7
Electrostatic Collector 0.3
Dust Injector 7.2
Shadow Shield 7.8
Master Equip List Mass incl 30% MGA
Base FFRE Design Revised FFRE Designs 
11.5 m
5.4 m Ø
2.8 m
Moderator
Reacting Dusty 
Plasma Cloud
Superconductors
Nozzle Beam 
Straightening 
Coils
Moderator Heat Shield
0.8 m
Superconducting 
Magnets
Spacecraft Concept Overview 
Low Temp 
(Super-
Conducting 
Magnet) 
Radiators 
Med Temp 
(Moderator) 
Radiators 
High Temp 
(Moderator Heat 
Shield) Radiators 
Aft RCS
Brayton Cycle 
Generators
Nuclear 
Shadow 
Shield
FFRE
Propellant 
Tank
FFRE
Magnetic 
Nozzle
FFRE
Reactor
Triangular 
Structure
60 mT Crew 
Habitat & 
Exploration 
Equipment Payload 
Avionics 
Radiators 
Fwd RCS 
15 
Spacecraft/Typical SLS Packaging 
Payload Packaging, hypothetical 12m shroud and >120mT capacity 
   FFRE & Braytons   Crew & Avionics Structure Backbone   Radiator       Radiators 
98.4'
33.1'
131.5'
27.53'
150.0'
171.7'
303.2'
93 0’
80.0’
98.4'
33.1'
131.5'
27.53'
150.0'
171.7'
303.2'
93 0’
80.0’
98.4'
33.1'
131.5'
27.53'
150.0'
171.7'
303.2'
93 0’
80.0’
98.4'
33.1'
131.5'
27.53'
150.0'
171.7'
303.2'
93 0’
80.0’
Spacecraft Performance 
(First FFRE / Spacecraft Assessment)  
Jupiter
Earth
Earth
Lunar Orbit
L1
E
a
rth
L
u
n
a
r O
rb
it
L
1
J
u
p
ite
r
E
a
rth
Jupiter Capture Interplanetary Earth Departure 
F
F
R
E
: 4
3
N
 T
h
ru
s
t, 5
2
7
,0
0
0
s
e
c
 S
p
e
c
ific
 Im
p
u
ls
e
A
d
d
in
g
 a
n
 “
A
fte
rb
u
rn
e
r”
 to
 F
F
R
E
 
b
o
o
s
ts
 th
ru
s
t, s
h
o
rte
n
s
 trip
, b
u
t 
a
d
d
s
 p
ro
p
e
lla
n
t w
e
ig
h
t:
E
x
a
m
p
le
: 4
3
0
N
 / 5
2
,7
0
0
s
e
c
 A
F
F
R
E
E
a
rth
T
h
ru
s
t
T
h
ru
s
t
C
o
a
s
t
J
u
p
ite
r
O
U
T
B
O
U
N
D
 
T
R
A
J
E
C
T
O
R
Y
  
R
E
S
U
L
T
S
S
E
G
M
E
N
T
 
T
I
M
E
 
(D
A
Y
S
)
O
U
T
B
O
U
N
D
 
E
L
A
P
S
E
D
 T
I
M
E
 
(D
A
Y
S
)
C
U
M
U
L
A
T
I
V
E
  
N
U
C
L
E
A
R
 P
R
O
P
 
(K
G
)
E
A
R
T
H
 S
P
I
R
A
L
-O
U
T
5
5
5
5
4
0
I
N
T
E
R
P
L
A
N
E
T
A
R
Y
2
1
0
6
2
1
6
1
1
5
5
4
J
U
P
I
T
E
R
 S
P
I
R
A
L
-I
N
5
0
3
2
6
6
5
1
9
1
6
C
A
L
L
I
S
T
O
 S
T
A
Y
 T
I
M
E
 3
3
0
 D
A
Y
S
I
N
B
O
U
N
D
 T
R
A
J
E
C
T
O
R
Y
 S
I
M
I
L
A
R
 T
O
 O
U
T
B
O
U
N
D
 (2
8
5
4
 D
A
Y
S
)
T
O
T
A
L
 M
I
S
S
I
O
N
 T
I
M
E
5
8
4
9
 (1
6
.0
)
d
a
y
s
 (y
e
a
rs
)
T
O
T
A
L
 T
H
R
U
S
T
I
N
G
 T
I
M
E
5
5
1
9
d
a
y
s
N
U
C
L
E
A
R
 F
U
E
L
4
m
T
O
U
T
B
O
U
N
D
 T
R
A
J
E
C
T
O
R
Y
 R
E
S
U
L
T
S
O
U
T
B
O
U
N
D
 
T
R
A
J
E
C
T
O
R
Y
  
R
E
S
U
L
T
S
S
E
G
M
E
N
T
 
T
I
M
E
 
(D
A
Y
S
)
O
U
T
B
O
U
N
D
 
E
L
A
P
S
E
D
 T
I
M
E
 
(D
A
Y
S
)
T
H
R
U
S
T
 T
I
M
E
 
(D
A
Y
S
)
E
A
R
T
H
 S
P
I
R
A
L
-O
U
T
4
4
4
I
N
T
E
R
P
L
A
N
E
T
A
R
Y
1
0
6
7
1
0
7
1
1
1
4
J
U
P
I
T
E
R
 S
P
I
R
A
L
-I
N
4
0
1
1
1
0
4
0
S
T
A
Y
 T
I
M
E
 A
T
 C
A
L
L
I
S
T
O
 A
T
 L
E
A
S
T
 1
2
0
 D
A
Y
S
T
O
T
A
L
 E
L
A
S
P
E
D
 M
I
S
S
I
O
N
 T
I
M
E
2
2
9
9
 (6
.2
)
d
a
y
s
 (y
e
a
rs
)
T
O
T
A
L
 T
H
R
U
S
T
I
N
G
 T
I
M
E
2
6
3
d
a
y
s
T
O
T
A
L
 F
U
E
L
 (N
U
C
 /
 C
H
4 )
0
.5
 m
T
 /
 2
1
.5
m
T
Earth Escape From L1 Interplanetary 
Jupiter / Callisto Capture 
Spacecraft is acceleration limited 
Isp 
Spacecraft Comparison 
What Is Learned So Far 
 A FFRE is credible – ordinary 
engineering, ordinary 
physics.  NO MIRACLES. 
 A FFRE-propelled spacecraft 
is game changing to travel in 
space.  A spacecraft  with a 
heavy payload can depart for 
and return from many solar 
system destinations.  NO 
REASSEMBLY REQUIRED. 
 Our first constructs of a 
FFRE are grossly inefficient.  
We are like a Ford Model T 
engine.  Only a few ways of 
improving performance of 
the FFRE and spacecraft 
have been considered.   
 
 
THERE’S MUCH WORK TO DO. 
HOPE 4.5yrs? 8-16 yrs  
Earth
Thrust
Thrust
CoastJupiter
Performance Trades 
Effect on Mission Of  
2nd Generation FFRE Design 
FFRE  
 Thrust: 2X (86N) 
 Isp: 527,000s 
Spacecraft 
 Assumed no change (conservative)  
Mission 
 ~8 years round trip 
 Spiral out and in times halved 
 Small coast period in interplanetary 
flight 
 Propellant: ~4 mT nuclear 
EarthJupiter
Coast
Effect  on Mission Of  
Adding an “Afterburner “  
to FFRE Design 
FFRE  
 Fission fragments accelerate an inert gas 
added to nozzle via friction, adding thrust     
& decreasing specific impulse 
 Thrust: 430N, Isp: 52,700s (notional) 
Spacecraft 
 Added “propellant” and tankage 
Mission 
 ~6 years round trip 
 From Earth: 4 days, Into Jupiter: 40 days 
 Interplanetary Coast: 950days 
 Propellant: 0.3mT nuclear, 22mT gas 

The 
Next 
Step: 
Lighting the Afterburner On A Fission 
Fragment Rocket Engine 
 
FY12 NIAC Proposal – 16April, 2012 
In Response To NRA NNH12ZUA002N 
 
Robert Werka PI 
MSFC EV-72 
 
 
Lighting The Afterburner On A Fission Fragment Rocket Engine 
 
FY 13 Center Innovation Fund Study Aw rd 


FFRE Powered Spacecraft

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server