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Questions tagged [efficiency]

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17 votes
1 answer

How much propellant is used up until liftoff?

How much of the total propellant mass (fuel+oxidizer) of the first stage/boosters is usually burnt between ignition and liftoff?
Everyday Astronaut's user avatar
4 votes
2 answers

How to compute each of these link budget terms?

The terms in Equation are all in decibels (dB), which is logarithmically scaled. In Equation, $P_{rx}$ is the received peak power, $P_{tx}$ is the transmitted peak power, $G_{tx}$ is the transmitter ...
Noel Miller's user avatar
-2 votes
3 answers

Can more thrust come from launching parallel to water?

Would having the exhaust of a rocket or air breathing engine in an early stage in close proximity to water on a horizontal launch provide more thrust? Could a rocket launch off water horizontally in ...
Muze's user avatar
  • 1
13 votes
2 answers

Is the concept of the Epstein Drive based on actual theorized scientific research which is considered plausable?

I've always found it interesting when we see real life taking its cues from fictional arts, especially when it comes to Science Fiction technology. There are plenty of examples of classic books, TV ...
BigNutz's user avatar
  • 555
9 votes
0 answers

What rocket uses the largest percentage of Fuel/Oxidizer before liftoff?

inspired by this question: How much propellant is used up until liftoff? which asks how much propellant (fuel/oxidizer) a typical rocket uses before liftoff. What has been or is the most non-typical ...
Sdarb's user avatar
  • 317
3 votes
1 answer

ISP losses associated with exhaust vane TVC

What is the impact of exhaust vanes, such as those in the A4 and Redstone rockets, on exhaust velocity and overall ISP? As well as this, what is the relationship between ISP losses and the width of ...
R. Hall's user avatar
  • 822
1 vote
1 answer

What is the point of having a central rocket engine when it receives performance losses?

Recently I asked this question about center engine performance and received an excellent answer from @OrganicMarble. The first sentence of the answer is If anything, the flow field interactions hurt ...
WarpPrime's user avatar
  • 3,125
1 vote
0 answers

Orbit to Orbit Transport Stage

Would it be faster or cheaper to have a lander, SSTO, and/or SpaceX Mars rocket to rendezvous connect with a more efficient engine or "transport stage" or another lander, SSTO? When the spacecraft ...
Muze's user avatar
  • 1