Could Jet Engines Be Used for Space Travel?

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Discussion Overview

The discussion centers around the feasibility of using jet engines for space travel, specifically whether they could produce sufficient thrust in low Earth orbit where atmospheric density is significantly reduced. Participants explore the limitations of jet engines compared to rocket engines in the context of space travel.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants propose that jet engines could produce thrust in low orbit due to the presence of some atmosphere, despite its low density.
  • Others argue that at altitudes like 70 miles, the atmosphere is too thin to support combustion, making traditional jet engines ineffective.
  • A participant suggests that an electrically or mechanically powered engine could work in place of a combustion engine, although this raises questions about the definition of a jet engine.
  • Concerns are raised about the practicality of gathering enough air for combustion at high altitudes, with one participant noting the need for a large air intake and powerful compressor.
  • Some participants clarify that orbiting does not require constant thrust, and that thrust is primarily needed to counteract drag and maintain orientation.
  • There is a discussion about the nature of thrust generation, with one participant emphasizing that a jet engine requires intake and combustion, which complicates the idea of using non-combustion methods.
  • Ion engines are mentioned as a potential alternative that does not require combustion or atmospheric oxygen, but they are noted to be ineffective in atmospheric conditions.

Areas of Agreement / Disagreement

Participants generally disagree on the viability of using jet engines for space travel, with multiple competing views on the definitions and functionalities of jet versus rocket engines. The discussion remains unresolved regarding the potential for non-combustion engines to provide meaningful thrust in low orbit.

Contextual Notes

Participants express uncertainty about the specific conditions required for jet engines to function at high altitudes and the implications of atmospheric density on thrust generation. There are also unresolved questions about the definitions and operational principles of different types of engines.

  • #31
BoeingJet said:
I think you are talking about the Buzzard Ramjet.
I think I would very much like to see this Buzzard Ramjet.
:woot:
 
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  • #32
DaveC426913 said:
I think I would very much like to see this Buzzard Ramjet.
Buzzard rams jet?
"An aircraft over the Ivory Coast collided with a Rüppell's vulture at the altitude of 11,300 m (37,100 ft), the current record avian height."
 
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  • #33
jbriggs444 said:
Buzzard rams jet?
"An aircraft over the Ivory Coast collided with a Rüppell's vulture at the altitude of 11,300 m (37,100 ft), the current record avian height."
Holy cow, that's high! And what did he win for his effort...?
 
  • #34
jbriggs444 said:
"An aircraft over the Ivory Coast collided with a Rüppell's vulture at the altitude of 11,300 m (37,100 ft), the current record avian height."
No way. That unlucky bird was sleeping in the intake when the jet was launched. It hung on as long as possible at the intake, but passed out at altitude and got the record for the highest bird "hit". o0)
 
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  • #35
Can't help but wonder what kind of natural selection pressure leads to birds capable of existing at that extreme altitude.
Well above the highest mountains and no food there.
Can get a really long distance glide from that height maybe?

Edit:
Berkeman's explanation noted.
 
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  • #36
Perhaps all the bird wanted was a jetstream hike...
 
  • #37
DaveC426913 said:
its orbit doesn't decay in a matter of mere hours?

The enterprise typically is not in orbit (contrary to what Kirk et al. say) but simply hovering using its impulse engines. Which are reaction-less drives thus nonsense (pending NASA investigation) and not relevant to scientific discussion.

BoB
 
  • #38
rbelli1 said:
The enterprise typically is not in orbit (contrary to what Kirk et al. say) but simply hovering using its impulse engines.
Yeah. No one's ever provided a satisfactory explanation.

Not having discovered orbital velocity in the 23rd centry is about as silly as any other explanation.
 

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