Transcript Presentation_Fernald - Lyle School of Engineering

Launch Vehicle Engine
Configuration Reliability Analysis
Nikolas Fernald
EMIS 7305
Spring 2011
Overview
•
•
•
•
•
•
•
Scope
Background
Approach
Analysis
Summary
Conclusion
Further Analysis
Scope
• Analysis of rocket engine reliability for various
rocket launch vehicle configurations.
▫ 2 and 3 stage to orbit configurations.
▫ 0, 1 and 2 engine out configurations*
• What is an ideal per-engine reliability to produce
a 99.0% system reliability for various launch
vehicle configurations?
* When applicable
Goal
• To gain a better understand of how engine
reliability rates affect overall stage and vehicle
engine reliability.
• To find a reasonable medium for stage engine
out capabilities.
Background (1/3)
• Commercial Launch Vehicle Development
▫ Focus:
 Cost
 Reliability
 Advanced Failure Tolerances
▫ Savings:
 Heritage rocket engine designs
 Designs developed with lessons learned from Apollo,
Shuttle, and Russian Rocket programs.
Background (2/3)
▫ Leading the Charge: SpaceX
 1 production engine family (Merlin 1C)
 Services Falcon 1, Falcon 9 and Falcon 9 Heavy rockets.
 78k lbf Sea Level Thrust
 90k lbf Vacuum Thrust
 1 development engine family (Merlin 2)
 Services: Not yet announced.
▫ Theorized single engine Falcon 9 size rocket, 3 stage cargo
vehicles.
 1.70M lbf Sea Level Thrust
 1.92M lbf Vacuum Thrust
 Saturn V – F1 class engine
Background (3/3)
• Launch Vehicle Failures
▫ 91 percent of launch vehicle failures in the past 2
decades can be traced back to one of three areas;
Rocket Engines, Stage Separation Failure, and
Avionics
• Economic Impact
▫ Technologies developed for space applications
continue to be utilized to dramatically improve human
life and progression.
▫ As commercial launch vehicles drive down costs and
increase reliability, the potential for economic leaps
and bounds for exploration and technology is seeming
limitless.
 With greater access to space research and development
will surly follow.
Approach (1/2)
• Examine rocket staging methods and
requirements and develop series and reliability
block diagrams.
• Assess:
▫ Reliably for the following configurations: (1st
stage/2nd stage/(optional 3rd stage))






1/1
3/1; 3x3/1
5/1; 5/2; 5x3/1; 5x3/2
9/1; 9/2; 9x3/1; 9x3/2
3/3/1; 3/3/2
5/3/1; 5/3/2; 5/5/1; 5/5/2
Approach (2/2)
• Assess (Continued)
▫ 0 engine out
▫ 1 engine out capable*
▫ 2 engine out capable*
• Equations
▫ Binomial distribution for engine out capabilities
 𝑅 𝑠𝑢𝑐𝑐𝑒𝑠𝑠𝑒 =
𝑛
𝑥
𝑟𝑥 1 − 𝑟
𝑛−𝑥
 n = engines
 x = successful through flight
 r = engine flight reliability
* When applicable to configuration; 5 engines 1 out capable, 9 engines 2 out capable.
Assumptions & Notes
• Reliability Calculations
▫ The same reliability factor for each stage is used in
the calculation to simplify the assessment.
 Current practiced task in industry to lower costs
using engine family rather than different designs.
• Equations
▫ Each vehicle reliability equation is broken down
between stages: Res1, Res2, Res3.
•
•
•
•
•
•
3/1 & 3/2
3x3/1 & 3x3/2
5/1 & 5/2
5x3/1 & 5x3/2
9/1 & 9/2
9x3/1 & 9x3/2
1/1 Configuration
•
•
•
•
1 engine 1st stage
1 engine 2nd stage
No engine out capability
Launch vehicle block diagram:
▫
1
1
Stage 1
Stage 2
• Reliability equation:
▫ 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 ∗ 𝑅𝑒𝑠2
• Results:
▫
Re
R(Vehicle)
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
97.02%
97.52%
98.01%
98.51%
99.00%
99.50%
3/1 & 3/2 Configuration (1/2)
• 3 engines 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• No engine out capability
• Launch vehicle block diagrams:
▫ 3/1
3/2
1
2
1
1
3
Stage 1
2
3
Stage 2
Note: Stage reliability calculations are in series.
1
Stage 1
2
Stage 2
3/1 & 3/2 Configuration (2/2)
• Reliability Equations
▫ 3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 3 ∗ 𝑅𝑒𝑠2
▫ 3/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 3 ∗ 𝑅𝑒𝑠2 2
• Results
▫
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
3/1
94.13%
95.09%
96.06%
97.03%
98.01%
99.00%
3/2
92.72%
93.90%
95.10%
96.31%
97.52%
98.76%
5/1 & 5/2 Configuration (1/3)
• 5 engines 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• 1 engine out capability in 1st stage
• Launch vehicle block diagrams:
▫ 5/1
5/2
1
2
1
2
3
1
3
4
4
5
5
Stage 1
Stage 2
Note: Stage reliability calculations are in series.
1
Stage 1
2
Stage 2
5/1 & 5/2 Configuration (2/3)
• Reliability Equations
▫ 1st stage 1 engine out capable
 5/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 5 +
5
4
𝑅𝑒𝑠1 4 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2
5
4
𝑅𝑒𝑠1 4 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2 2
 5/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 5 +
▫ 1st stage no engine out capable
 5/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 5 ∗ 𝑅𝑒𝑠2
 5/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 5 ∗ 𝑅𝑒𝑠2 2
5/1 & 5/2 Configuration (3/3)
• Results
▫
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
1 Engine Out
No Engine Out
5/1
98.28%
98.60%
98.90%
99.20%
99.48%
99.74%
5/2
96.81%
97.37%
97.91%
98.45%
98.98%
99.49%
5/1
91.33%
92.73%
94.15%
95.58%
97.04%
98.51%
5/2
89.96%
91.57%
93.21%
94.87%
96.55%
98.26%
9/1 & 9/2 Configuration (1/3)
• 9 engines 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• Up to 2 engine out capability in 1st stage
• Launch vehicle block diagrams:
▫ 9/1
1
9/2
2
1
2
3
3
4
4
5
1
5
6
6
7
7
8
8
9
9
Stage 1
Stage 2
Note: Stage reliability calculations are in series.
1
Stage 1
2
Stage 2
9/1 & 9/2 Configuration (2/3)
• Reliability Equations
▫ 1st stage 2 engine out capable
 9/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1 +
9
7
𝑅𝑒𝑠1 7 1 − 𝑅𝑒𝑠1
2
∗ 𝑅𝑒𝑠2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1 +
9
7
𝑅𝑒𝑠1 7 1 − 𝑅𝑒𝑠1
2
∗ 𝑅𝑒𝑠2 2
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2 2
 9/2
▫ 1st stage 1 engine out capable
 9/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
 9/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
▫ 1st stage no engine out capable
 9/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 ∗ 𝑅𝑒𝑠2
 9/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 ∗ 𝑅𝑒𝑠2 2
9/1 & 9/2 Configuration (3/3)
• Results

Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
2 Engine Out
9/1
98.42%
98.70%
98.98%
99.24%
99.50%
99.75%
9/2
96.95%
97.47%
97.99%
98.50%
99.00%
99.50%
R(Vehicle)
1 Engine Out
9/1
96.29%
97.19%
97.98%
98.67%
99.24%
99.68%
9/2
94.84%
95.97%
97.00%
97.93%
98.74%
99.43%
No Engine Out
9/1
65.50%
70.31%
75.47%
80.99%
86.91%
93.23%
9/2
64.51%
69.43%
74.72%
80.39%
86.47%
93.00%
3x3/1 & 3x3/2 Configuration (1/3)
• 3 engines in 3 common cores 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• No engine out capability
• Reliability Equations
▫ 3x3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1
33
∗ 𝑅𝑒𝑠2
▫ 3x3/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1
33
∗ 𝑅𝑒𝑠2 2
3x3/1 & 3x3/2 Configuration (2/3)
• Launch vehicle block diagrams:
▫ 3x3/1
3x3/2
1
1
2
2
3
3
1
1
2
1
3
3
1
1
2
2
3
3
Stage 1
Stage 2
Note: Stage reliability calculations are in series.
1
2
Stage 1
2
Stage 2
3x3/1 & 3x3/2 Configuration (3/3)
• Results
▫
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
3x3/1
3x3/2
85.97%
84.68%
88.18%
87.08%
90.44%
89.53%
92.75%
92.05%
95.11%
94.64%
97.53%
97.28%
5x3/1 & 5x3/2 Configuration (1/4)
• 5 engines in 3 common cores 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• Engine out capability in 1st stage
▫ 1 out
▫ 0 out
5x3/1 & 5x3/2 Configuration (2/4)
• Launch vehicle block diagrams:
▫ 5x3/1
5x3/2
1
2
1
2
3
3
4
4
5
5
1
1
2
2
3
1
3
4
4
5
5
1
1
2
2
3
3
4
4
5
5
Stage 1
Note: Stage reliability calculations are in series.
Stage 2
1
Stage 1
2
Stage 2
5x3/1 & 5x3/2 Configuration (3/4)
• Reliability Equations
▫ 1st stage 1 engine out capable
 5x3/1
5
5
4
5
5
4
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 +
4
𝑅𝑒𝑠1 1 − 𝑅𝑒𝑠1
3
∗ 𝑅𝑒𝑠2
 5x/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 +
4
𝑅𝑒𝑠1 1 − 𝑅𝑒𝑠1
▫ 1st stage 0 engine out capable
 5x3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1
5 3
∗ 𝑅𝑒𝑠2
 5x/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1
5 3
∗ 𝑅𝑒𝑠2 2
3
∗ 𝑅𝑒𝑠2 2
5x3/1 & 5x3/2 Configuration (4/4)
• Results:
▫
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
1 Engine Out
No Engine Out
5x3/1
97.86%
98.30%
98.71%
99.09%
99.43%
99.73%
5x3/2
96.39%
97.07%
97.72%
98.34%
98.93%
99.48%
5x3/1
78.52%
81.77%
85.15%
88.65%
92.29%
96.07%
5x3/2
77.34%
80.75%
84.29%
87.99%
91.83%
95.83%
9x3/1 & 9x3/2 Configuration (1/4)
• 9 engines in 3 common cores 1st stage
• 2nd stage
▫ 1 engine
▫ 2 engine
• Engine out capability in 1st stage
▫ 2 out
▫ 1 out
▫ 0 out
5x3/1 & 5x3/2 Configuration (2/4)
• Launch vehicle block diagrams:
▫ 9x3/1
Common Core
1
2
C1
C2
3
1
4
5
C3
Stage 1
6
Stage 2
8
▫ 9x3/2
C1
9
Common Core
1
C2
C3
Stage 1
7
2
Stage 2
Note: Stage reliability calculations are in series.
9x3/1 & 9x3/2 Configuration (3/4)
• Reliability Equations
▫ 1st stage 2 engine out capable
 9x3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1 +
9
7
𝑅𝑒𝑠1 7 1 − 𝑅𝑒𝑠1
2 3
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1 +
9
7
𝑅𝑒𝑠1 7 1 − 𝑅𝑒𝑠1
2 3
9
8
𝑅𝑒𝑠1 8 1 − 𝑅𝑒𝑠1
 9x3/2
▫ 1st stage 1 engine out capable
 9x3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 +
 9x3/2
9
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 +
9
8
8
𝑅𝑒𝑠1 1 − 𝑅𝑒𝑠1
▫ 1st stage no engine out capable
 9x3/1
3
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 ∗ 𝑅𝑒𝑠2
 9x3/2
3
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 9 ∗ 𝑅𝑒𝑠2 2
3
3
∗ 𝑅𝑒𝑠2
∗ 𝑅𝑒𝑠2 2
∗ 𝑅𝑒𝑠2
∗ 𝑅𝑒𝑠2 2
9x3/1 & 9x3/2 Configuration (4/4)
• Results
▫
2 Engine Out
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
9/1
96.95%
97.47%
97.99%
98.50%
99.00%
99.50%
9/2
96.95%
97.47%
97.99%
98.50%
99.00%
99.50%
R(Vehicle)
1 Engine Out
9/1
96.29%
97.19%
97.98%
98.67%
99.24%
99.68%
9/2
94.84%
95.97%
97.00%
97.93%
98.74%
99.43%
No Engine Out
9/1
65.50%
70.31%
75.47%
80.99%
86.91%
93.23%
9/2
64.51%
69.43%
74.72%
80.39%
86.47%
93.00%
• 3/3/1 & 3/3/2
• 5/3/1 & 5/3/2
• 5/5/1 & 5/5/2
3/3/1 & 3/3/2 Configuration (1/2)
• 3 engines 1st stage
• 3 engines 2nd stage
• 3rd stage
▫ 1 engine
▫ 2 engine
• No engine out capability
• Reliability Equations
▫ 3/3/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 3 ∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3
▫ 3/3/2
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 3 ∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3 2
3/3/1 & 3/3/2 Configuration (2/2)
• Launch vehicle block diagrams:
1
1
▫ 3/3/1
2
2
3
3
Stage 1
Stage 2
1
1
2
2
3
3
Stage 1
Stage 2
▫ 3/3/2
• Results
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
3/3/1
89.96%
91.57%
93.21%
94.87%
96.55%
98.26%
Note: Stage reliability calculations are in series.
3/3/2
88.61%
90.43%
92.27%
94.16%
96.07%
98.02%
1
Stage 3
1
1
Stage 3
5/3/1 & 5/3/2 Configuration (1/4)
• 5 engines 1st stage
• 3 engines 2nd stage
• 3rd stage
▫ 1 engine
▫ 2 engine
• Engine out capability in 1st stage
▫ 1 out
▫ 0 out
5/3/1 & 5/3/2 Configuration (2/4)
• Launch vehicle block diagrams:
▫ 5/3/1
1
2
1
3
2
4
3
1
5
Stage 1
Stage 2
Stage 3
▫ 5/3/2
1
2
1
3
2
4
3
1
1
5
Stage 1
Stage 2
Note: Stage reliability calculations are in series.
Stage 3
5/3/1 & 5/3/2 Configuration (3/4)
• Reliability Equations
▫ 1st stage 1 engine out capable
 5/3/1
 𝑅 𝑉𝑒ℎ. = 𝑅𝑒𝑠1 5 +
5
4
𝑅𝑒𝑠1 4 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3
5
4
𝑅𝑒𝑠1 4 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3 2
 5/3/2
 𝑅 𝑉𝑒ℎ. = 𝑅𝑒𝑠1 5 +
▫ 1st stage 0 engine out capable
 5/3/1
 𝑅 𝑉𝑒ℎ. = 𝑅𝑒𝑠1 5 ∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3
 5/3/2
 𝑅 𝑉𝑒ℎ. = 𝑅𝑒𝑠1 5 ∗ 𝑅𝑒𝑠2 3 ∗ 𝑅𝑒𝑠3 2
5/3/1 & 5/3/2 Configuration (4/4)
• Results
▫
R(Vehicle)
1 Engine Out
No Engine Out
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
5/3/1
93.93%
94.95%
95.97%
96.98%
97.99%
99.00%
5/3/2
92.52%
93.76%
95.01%
96.25%
97.50%
98.75%
5/3/1
87.28%
89.30%
91.35%
93.45%
95.59%
97.77%
5/3/2
85.97%
88.18%
90.44%
92.75%
95.11%
97.53%
5/5/1 & 5/5/2 Configuration (1/4)
• 5 engines 1st stage
• 5 engines 2nd stage
• 3rd stage
▫ 1 engine
▫ 2 engine
• Engine out capability in 1st & 2nd stage
▫ 1 out
▫ 0 out
5/5/1 & 5/5/2 Configuration (2/4)
• Launch vehicle block diagrams:
▫ 5/5/1
1
1
2
2
3
3
4
4
5
5
Stage 1
Stage 2
1
Stage 3
▫ 5/5/2
1
1
2
2
3
3
4
4
5
5
Stage 1
Stage 2
Note: Stage reliability calculations are in series.
1
2
Stage 3
5/5/1 & 5/5/2 Configuration (3/4)
• Reliability Equations
▫ 1st & 2nd stage 1 engine out capable
 5/5/1
 𝑅 𝑉𝑒ℎ𝑖𝑐𝑙𝑒 = 𝑅𝑒𝑠1 5 +
5
4
𝑅𝑒𝑠1 4 1 − 𝑅𝑒𝑠1
∗ 𝑅𝑒𝑠2 5 +
5
4
𝑅𝑒𝑠2 4 1 −
5/5/1 & 5/5/2 Configuration (4/4)
• Results
▫
Re
98.50%
98.75%
99.00%
99.25%
99.50%
99.75%
R(Vehicle)
1 Engine Out
No Engine Out
5/5/1
98.07%
98.45%
98.81%
99.14%
99.45%
99.74%
5/5/2
96.60%
97.22%
97.82%
98.40%
98.95%
99.49%
5/5/1
84.68%
87.08%
89.53%
92.05%
94.64%
97.28%
5/5/2
80.93%
83.85%
86.87%
90.00%
93.22%
96.56%
Summary (1/2)
Two Stage Analysis Results
Config.
1/1
3/1
3/2
5/1
5/2
9/1
9/2
3x3/1
3x3/2
5x3/1
5x3/2
9x3/1
9x3/2
99.00%
98.01%
96.06%
95.10%
98.90%
97.91%
98.99%
97.67%
90.44%
89.53%
98.71%
97.72%
98.98%
97.99%
R(Engine)
99.50%
99.00%
98.01%
97.52%
99.48%
98.98%
99.50%
98.92%
95.11%
94.64%
99.43%
98.93%
99.50%
99.00%
99.75%
99.50%
99.00%
98.76%
99.74%
99.49%
99.75%
99.48%
97.53%
97.28%
99.73%
99.48%
99.75%
99.50%
Note: Maximum Reliability Configurations.
Three Stage Analysis Results
Config.
3/3/1
3/3/2
5/3/1
5/3/2
5/5/1
5/5/2
99.00%
93.21%
92.27%
95.97%
95.01%
98.81%
97.82%
R(Engine)
99.50%
96.55%
96.07%
97.99%
97.50%
99.45%
98.95%
99.75%
98.26%
98.02%
99.00%
98.75%
99.74%
99.49%
Summary (2/2)
• Engine out capability is nearly a must for stage engine
configurations over 3 engines.
• Common core configurations (#engines x 3) benefit
significantly from engine out capability.
• 3 stage launch vehicles benefit significantly from engine
out capability.
• Final stage engines greatly effect launch vehicle
reliability due to the lack of engine out capability
• Engine reliability greater than 99.75% is necessary for
nearly all configurations to achieve a launch vehicle
(engine only) reliability of 99.50%
Conclusions
• Engine out capabilities for stages with over 3
engines is nearly a must to maintain a 99.5%
vehicle reliability.
• For a 9 engine stage or core, a two engine out
capability does not increase reliability with
much significance.
• A 3x3/1 or 3x3/2 configuration is not capable of
high reliability due to the lack of a engine out
capability.
Recommendation
• The final stage requires a highly reliable engine to
maintain a high total launch vehicle reliability. A
single engine final stage is preferable over a dual
engine stage.
• Achieving maximum engine out capabilities for a
given stage is a recommended practice which can
significantly drive reliability, especially in a three
stage rocket.
• The use of common engines between stages would
seem to be highly beneficial such that costs are
minimized a to drive up engine reliability numbers.
Thank You