Questions tagged [mass-fraction]
The mass-fraction tag has no usage guidance.
29
questions
1
vote
3
answers
234
views
Propellant Density Calculation for LOX/Kero
I am trying to make sense of the equation for propellant density calculation, rho=(rw-1)/(rw/bo+1/bf).
Sutton, 7th edition, gives this equation (7-2) as:
$ \ \ \ \rho_{av} = \frac {\rho_o\rho_f(1+r)} {...
- 11
1
vote
0
answers
99
views
Why does the Star-5A have such a bad mass ratio?
I went over the KSP-RO's Discord research notes and found this PDF about the Star kick motors. The OP wrote that the Star-5A had a mass ratio of 0.493, which seems extremely low from a solid motor ...
- 3,085
3
votes
1
answer
275
views
Is this a plot of Isp vs propellant mass fraction for a SSTO vehicle?
Whilst trying to find some information on SSTO designs, I came across this chart:
It was used in an ancient forum thread by as part of an SSTO discussion, but the poster didn't cite the paper they'd ...
- 7,714
5
votes
6
answers
2k
views
If money weren't an issue, what's the best way to get maximum mass to LEO in 1 year? 5 years? 10? [closed]
I can kick this over to World Building if it's more appropriate, but I was hoping to get an actual technical examination of this.
So here's the question: if money were not an issue and for some reason ...
- 1,428
1
vote
0
answers
114
views
How much of a deep space spacecraft's structural mass is useless dead weight after launch? Any plans to shed it in the future?
After seeing this in Security SE
Magnetic core memory isn't quite extinct yet. The two Voyager spacecraft used it and are still functional. Core was/is certainly non-volatile.
I did some ...
- 148k
2
votes
1
answer
994
views
Does a fully fuelled Starship in LEO have 0kg payload to Jupiter?
So I was looking into the payload mass a fully fuelled Centaur V could send to Jupiter and used the formula in presented in this answer to create a C3 graph. For a bit of fun I also looked into the ...
- 3,991
12
votes
1
answer
699
views
How does tankage mass really scale?
A problem that frequently shows up is estimating the mass of the propellant tanks of some hypothetical rocket configuration. This need arises from the important role of the dry mass in a rather famous ...
6
votes
2
answers
1k
views
How much fuel, (in tons) will a dedicated tanker be able to deliver to a starship in LEO?
The starship tankers that will refuel starships in orbit will only carry fuel. I’ve heard it described that at first they will simply be normal starships, but with more fuel leftover when they reach ...
- 4,854
3
votes
1
answer
926
views
mass of propellant required + rocket equation
I'm doing some research for a class project and I have a questions about the use of the rocket equation to get the propellant mass required. If $m_1$ is the final mass, and $m_0$ is the initial mass, ...
- 111
6
votes
1
answer
222
views
Are there active (as of 2020) developments in liquid-fuel tank technology?
This question was broken off from previous mega-question located here.
I am aware of the broad liquid fuel tank types:
V-2-style steel fuselage
Integral steel
Integral aluminum (with varying types ...
- 10.6k
2
votes
0
answers
102
views
Can you help me fill in the gaps in my liquid-fuel rocket propellant tank technology knowledge? [closed]
I am currently aware of the following types of propellant tank technology:
Steel fuselage, used in the V-2/A-4 & other rockets of its era (essentially a plane body)
Integral steel tanks, first ...
- 10.6k
3
votes
1
answer
1k
views
What are Mass Rate(∆v)/∆v, Mass Rate(Isp)/Isp and time of burn(MR)/MR graphs?
I have some problems about Tsiolkovsky's Rocket Equation and some graphs.
Firstly, I didn't get what I can do with Rocket Equation formulas as seen below,
Also, what these three graphs try to mean? ...
- 241
5
votes
1
answer
492
views
Would the Space Shuttle External Tank have made orbit as a VT SSTO with 6 SSMEs?
Dropping the external boosters and also the entire 75-100 ton orbiter from the picture, would the tank all by itself have made orbit? This would require bolting at least 5, better 6, perhaps even 9 ...
- 113
8
votes
5
answers
4k
views
Conceptually, the lower the propellant mass fraction the better, right?
Rocket Propulsion Elements, 7th ed. Sutton, pg 30 states: "A high value of the propellant mass fraction is desirable." - I tend to disagree with this statement as described in that section ...
- 135
2
votes
1
answer
324
views
Problem in finding propellant mass using rocket equation, where total mass includes components dependent on propellant mass
Formulation:
$$e^{\Delta v/v_{exhaust}} - 1=\frac{mass_{fuel}}{mass_{structure}}$$ $$\text{let } k=e^{\Delta v/v_{exhaust}} - 1 \implies mass_{fuel}= k \times mass_{structure} $$
According to SMAD (...
- 329
3
votes
0
answers
101
views
Understanding the multi-stage mass tables in Wiesel's Spaceflight Dynamics
In Wiesel's Spaceflight Dynamics, 3rd Edition (2010) Chapter 7.5 (pg 220), there is a table of mass values for Von Braun's 1951 design for a three-stage space station supply rocket. In the book, the ...
- 1,974
14
votes
1
answer
1k
views
Flying fuel tanks! Which deep-space spacecraft had the largest fuel mass fraction?
The Los Angeles Times' Deborah Netburn just wrote a really nice retrospective; ‘OK. Let’s do it!’ An oral history of how NASA’s Cassini mission to Saturn came to be with plenty of photos and quotes ...
- 148k
8
votes
1
answer
1k
views
Why will SLS Block I bring less mass to LEO than the STS shuttle system did?
The Space Transportation System (STS) could bring a fully loaded shuttle orbiter of 109 tons to orbit (or maybe empty+payload 68+25=93 tons). The Space Launch System (SLS) Block I is based on STS, but ...
- 26.9k
6
votes
2
answers
5k
views
Fuel needed for rocket lift-off as a function of the altitude
Suppose I want to send a rocket to Mars, or to the Moon, from earth.
How much fuel (in percentage of the full load) is needed for the rocket lift-off as a function of the altitude?
I don't know if it ...
- 481
5
votes
2
answers
638
views
How much fuel can Falcon 9's upper stage bring to orbit, without any other payload?
I wonder how useful SpaceX' second stage would be as a propulsion stage docking in LEO or so with separately launched payload. It seems to carry 92 tons of propellant on the launch pad. How much could ...
- 26.9k
3
votes
5
answers
541
views
Could fuel be "hosed" (pumped) from the ground to a launcher?
Most fuel on board a launcher is used during the first couple of minutes. Most of the propellant is needed to carry other propellant. For example, Saturn V (kerosene) and Delta IV (hydrogen) use about ...
- 26.9k
1
vote
1
answer
352
views
How does the mass of launchers change over time between ground and orbit?
I would like to see some comparison between different launchers wrt how quickly their mass is reduced over time (or altitude or velocity). There are differences in overall size class, propellant type, ...
- 26.9k
4
votes
0
answers
608
views
Falcon 9 v1.1 Full Thrust Specifications
Does anyone know what the dry mass and mass ratio of the Falcon 9v1.1 Full Thrust Stage 1 is? The best info I've been able to find was by taking the specified burn time and multiplying it by the mass ...
- 421
15
votes
3
answers
5k
views
Is this a correct understanding of Tsiolkovsky's rocket equation?
When I graph the rocket equation, substituting arbitrary values for v(exhaust) and m1, so m0 because m1 - m0, the graph implies that increasing propellant mass past a certain point does not increase ...
- 443
14
votes
2
answers
3k
views
How much mass could the Saturn V rockets have landed on the Moon if nothing was coming back?
What dry mass could have soft-landed on the Moon if a Saturn V had been reconfigured to launch a robotic mission going entirely to the surface? Obviously, that wasn't possible at the time, but for a ...
- 21.2k
14
votes
4
answers
3k
views
Why are rocket mass on the launch pad and payload mass to LEO not strongly correlated?
What explains the relation between how much a launcher weights on the launch pad, and how much mass it can lift to orbit?
I had expected that more payload requires more fuel to be launched and that a ...
- 26.9k
8
votes
3
answers
4k
views
How is "payload to LEO" estimated for a launcher?
Payload to LEO is commonly used as the bottom line of what a launcher can accomplish. But it must depend on factors which are not launcher specific, such as launch location and orbital characteristics....
- 26.9k
5
votes
1
answer
683
views
Why are pressure-stabilized rockets not more common?
The Atlas rockets and Centaur upper stages (often used in combination) successfully use(d) pressure-stabilized tanks to minimize dry mass. This technology was not used in any other rocket stages I'm ...
- 469
4
votes
1
answer
878
views
Most energy efficient mass ratio of a rocket, or exhaust velocity
In the process of thinking about some hard science fiction, I need to substitute some mass fractions that will minimize the amount of energy used in order to be maximally generous to the author. So ...
- 16.2k