Questions tagged [performance]

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1answer
116 views

Can a lighter rocket lift more than a heavier rocket?

Let us consider two launch vehicles - "A" and "B". If "A" has a larger wet mass than "B", does this imply "A" has a higher payload capacity to a particular orbit, from a particular launch site than "B"...
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2answers
232 views

Why was Apollo 11 launched in summer?

The question could seems stupid, but I think that best moment to launch a rocket is when temperature is lowest in order to achieve the best performance in a reaction engine. I do not know if there is ...
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30 views

How does a NTR with an afterburner perform at a stoichiometric mixing ratio?

The LANTR entry at Encyclopedia Astronautica describes how a sample nuclear thermal rocket performs at various mixing ratios of LH2/LOX. It does however stop before reaching the stoichiometric ratio ...
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3answers
71 views

When would the density Isp product be an important performance metric of a propellant?

The quote NASA is testing hydroxylammonium nitrate in space which is expected to perform 50% better than standard propellants and can be allowed to freeze (hydrazine must be kept liquid). LMP-103S ...
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2answers
581 views

What performance specification would be lower for Krypton than for Xenon in Hall effect thrusters?

The Ars Technica article SpaceX scrubs first attempt to launch 60 Internet satellites [Updated] (found here) discusses the use of Krypton rather than Xenon in the Starlink Hall effect ion thrusters: ...
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5answers
8k views

How much bigger could Earth be, before rockets would't work?

hint: Apparently the Tsiolkovsky rocket equation does not actually say that you can launch a conventional rocket into orbit around an arbitrarily large and massive body. Question: "How much bigger ...
2
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4answers
831 views

In the context of calculating mass flow rate from thrust and Isp, how would an additional efficiency be defined?

In this answer I show a quickie derivation for calculating a mass flow rate of a rocket from a known thrust and Isp. A comment there says: That assumes 100% efficiency and ignores the fuel ...
14
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2answers
3k views

Benefit of Raptor Engines

I know that the Raptor engines are significantly different from the Merlin 1-D's since they use liquid methane and are cryogenic. However, what exactly enables the Raptor engines to produce a lot more ...
4
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2answers
400 views

Generating plot of LV's performance as a function of the C3 parameter

Following my previous question about Ariane 5 performance data for escape missions, I would like to know how the plot of launch vehicle capabilities like the next one are obtained: More specifically, ...
14
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3answers
1k views

Why can Falcon Heavy bring 4.2 times as much mass to Mars than F9, but only 2.7 times as much to LEO?

In Wikipedia's article SpaceX Falcon-Heavy the section titled Capabilities has a table comparing maximum payload masses to Falcon 9 for different payload destination. The current numbers there are ...
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0answers
169 views

What is the effect of launching from higher altitude on fuel burn and rocket performance? [duplicate]

There are many sites around the world apart from USA, that have such great locations to launch from. Saving hundreds of thousands of dollars in fuel costs. Can someone assist me with a model that ...
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1answer
2k views

There are better oxidizer than oxygen?

Liquid oxygen is cheap to obtain and available, but are there better oxidizers to achieve bigger thrust with JP1?
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1answer
644 views

Comparison between solid rocket fuels. Which are better by performance and cost? [closed]

I am interested for a comparison of solid rocket fuels by their performance and cost. Comparison by specific impulse (Isp), energy that gives (which one is more energitic), density, cost to ...
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0answers
88 views

ULA/Ball Aerospace Intern Sport Rocket

So I've seen ULA post about their intern rocket launch a couple of weekends ago and was curious: What are the performance specs on the motors used for the first/second stage? (Class, quantity, etc.) ...
6
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2answers
845 views

How does Rocket performance compare to other things?

Typically cars are rated on their 0-60 mph times. (Tesla's currently kicking some serious gas car butt, where the P90D with Ludicrous mode hitting 2.8s which is literally ludicrous. As in you can hurt ...
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2answers
1k views

Can someone tell me the effect on performance of overexpanded nozzles?

I understand that underexpanded nozzles lose efficiency, due to untapped potential in the gas before exiting the nozzle, but what happens to overexpanded nozzles? I understand that the pressure of the ...
6
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1answer
309 views

Could oxygen be used in a resistojet in a vacuum environment?

Resistojets heat a compressed gas or vaporize a liquid to expand it through a nozzle for thrust. They improve a bit on the performance of cold gas thrusters. This experimental water resistojet managed ...
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3answers
5k views

Do any current ICBM's have the delta-V to target the sun?

Based on an XKCD comic, XKCD 1626 which has the image: Do any of the active duty ICBM's have the ability to actually target the Sun? Considering that the R-7 booster that is the basis used by Soyuz/...
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216 views

How much extra performance could Falcon 9 have if launched from the equator? [duplicate]

Today I learned about Sea Launch, essentially a launch pad floating on the sea. (Pretty crazy, right?) What's cool about that is that you can launch from the equator without the tricky part about ...
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3answers
2k views

How does the roll maneuver allow more mass to be lifted into orbit?

I read recently that the roll maneuver that rockets perform shortly after clearing the tower to become tilted serves a few purposes (Shuttle and Apollo Saturn V alike). I understand most of these ...
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1answer
462 views

What was the thrust-to-weight ratio during liftoff of the Atlas V OA-4 launch?

It seemed to me that today's (Dec. 6, 2015) launch of ULA's Atlas V carrying Orbital ATK's Cygnus spacecraft in orbit and towards the International Space Station on the OA-4 mission had a particularly ...
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1answer
492 views

Ariane 5 performance data for escape missions

I would like to know the performance for escape mission of the Ariane 5 launcher. More precisely, I would like "LV Performance vs. C 3" curve. My problem is, I can find this info for a lot of ...
5
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1answer
333 views

What payloads and launch speeds could a sling launcher get using modern materials on the Moon?

The only reference paper I have found on this subject is this paper by Landis, which is a great introduction to sling launchers - but the concept has been around for some time and there must be other ...
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2answers
2k views

Do payloads with living creatures get launched slower to minimize G forces?

I've seen a few Space Shuttle and rocket launches in-person, and it always seemed to me that the Shuttle would launch a bit slower than rockets. Today, I saw the CRS-6 launch of the Falcon 9 and its ...