Launcher engine counts vary based on thrust optimization, reliability, and engineering constraints.
the verdict
SUPPORTED
the evidence backs this
refutedsupported
the weight of evidence
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AS REPORTEDno primary record reached; this is what the reporting says
Technical literature and engineering design discussions report that variations in launcher engine counts depend on propulsion trade-offs, reliability models, thrust size, and design constraints.
# What are the major tradeoffs for a launch vehicle having either one 400 kN engine or eight 50 kN engines?
- Tags: rockets, engines, engine-design, design, mission-design
- Score: 3
- Views: 192
- Answers: 0 (unanswered)
- Asked by: Muhammad Ahsan (31 rep)
- Asked on: Oct 25, 2023
- Last active: Oct 25, 2023
- License: CC BY-SA 4.0
---
## Question
Given the problem of choosing to build and launch a small rocket to put a smallsat into orbit with either of these two configurations, what are the major tradeoffs between them?
For specific issues feel free to link to previous posts for supporting information.
1. One 400 kN engine
2. Eight 50 kN engines
---
## Comments
- **Steve Pemberton**: @OrganicMarble - the previous question only asked about the challenges of many engines, i.e. the con. This question is asking for both pro and con (after the fix by uhoh, the original question asked which is "best", which is unanswerable). And it defines a specific scenario, although maybe that has little effect on the possible answers. Perhaps a better approach to avoid duplication of information would be to start by referring to the list of cons in the previous question, and then ask what
Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity Analysis - NASA Technical Reports Server (NTRS)
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Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity AnalysisThis paper is to address the in-flight reliability of a liquid propulsion engine system for a launch vehicle. We first establish a comprehensive list of system and sub-system reliability drivers for any liquid propulsion engine system. We then build a reliability model to parametrically analyze the impact of some reliability parameters. We present sensitivity analysis results for a selected subset of the key reliability drivers using the model. Reliability drivers identified include: number of engines for the liquid propulsion stage, single engine total reliability, engine operation duration, engine thrust size, reusability, engine de-rating or up-rating, engine-out de
# Why is there so much variation in the number of engines on launchers?
Tags: launch, rockets, design, engines
- Score: 11
- Views: 2499
- Answers: 2
- Answered: yes
- Asked by: Max Q Lagrange (2750 rep)
- Asked: 2015-07-29
- Edited: 2015-07-30
- Site: space
## Question
There is much variation in the number of engines used in the liftoff stage of various launchers.
Saturn V had 5
Space shuttles had 5 (3 main + 2 SRB)
Falcon 9 has 9
Soyuz has 20
N1 had 30
Delta Heavy has 3
Long March 3B appears to have 4 main + 2 or 4 boosters
Ariane 5 had 1 main + 2 boosters
While the size and performance of these launchers varies, I can't see any straightforward correlation between those factors and the number of engines. The only correlation I can see is that Soviet/Russian launchers have a whole lot more and smaller engines.
What are the design tradeoffs when deciding to use many small engines vs few large engines?
Why does the Soviet/Russian calculus seem to be so different to everyone elses in this regard?
## Answers
### Answer by geoffc (score: 12 [ACCEPTED])
The number of engines and strapons are a series of tradeoffs made based on available technology.
The Americans, planning a
Everything we examined (3) — 2 independent sources
This check searched the claim as stated. It did not run a separate search for evidence against it.