Questions tagged [rockets]

Questions regarding the boosters or thrusters used to propel man-made objects. For rockets firing opposite the primaries, see [retrorockets]. See wiki for other related tags.

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18 votes
6 answers
4k views

What makes aluminum aerospace grade?

So what is aerospace grade aluminum? Aerospace grade and regular aluminum or both aluminum. Do they have a different composition or strength? What makes one aerospace grade?
0 votes
2 answers
96 views

What is the maximum weight a raptor 2 engine can lift up at sea level on earth?

Regardless of target orbit, how can I calculate the maximum weight one engine can lift? If the raptor's TWR is 140 and its Thrust is 1.81 MN then: W = F / TWR = 12,900 N ==> m = W / g = 1.3 tons ...
7 votes
4 answers
2k views

Is aerodynamic lift ever useful in rocket flight?

When a rocket is traveling through an atmosphere, the component of the aerodynamic force in the direction of motion is called drag, and the component perpendicular to that is called lift. Usually a ...
17 votes
3 answers
3k views

What is the best chemical rocket fuel from a purely specific impulse standpoint?

A variety of different rocket programs use a variety of different fuel types. Researching this, the main fuel combinations I saw were: RP-1 / LOX (SpaceX's Falcon rockets, early stage Atlas and Saturn ...
1 vote
4 answers
126 views

Selecting an optimal Isp / what makes an Isp too high (mostly for high Isp)

When, and why, is it possible to have an Isp (usually of an ion or nuclear engine with Isp far beyond the limits of chemical fuel) that's too high? What makes the Isp too high, and (other things being ...
9 votes
3 answers
4k views

How might SpinLaunch actually spin something fast enough to launch it into orbit?

update: TechCrunch's SpinLaunch spins up a $35M round to continue building its space catapult is worth a read and contains this cool rendering. Click for full size Ars Technica's Edition 1.34 of the ...
0 votes
1 answer
145 views

Mass production rate vs mass consumption rate in solid rockets

Do the two terms mean the same? mass production rate, mass flow rate and mass consumption rate in a solid propellant rockets.
47 votes
1 answer
5k views

What safety protocols did this Pythom Space rocket crew ignore?

The video below of Pythom Space's first rocket test has raised a few eyebrows The video prompted hundreds of replies on Twitter, including some from rather horrified rocket scientists. "We knew ...
11 votes
1 answer
2k views

Does the debris from the re-entry of Long March core stage ever reach the surface?

It's common for SpaceX to de-orbit the second stage over the ocean (since they still have fuel for controlled re-entry,) but for the Long March core stage that is not the case. Meteorites have hit the ...
5 votes
2 answers
171 views

How do kick motors distance themselves from their payload after their burn, if at all?

I saw Space News' An object is now orbiting alongside China’s Shijian-21 debris mitigation satellite recently about a "new object" orbiting near a relatively newly launched satellite. The ...
17 votes
3 answers
2k views

Why did the Vanguard rocket use a solid engine for its third stage?

The Vanguard rocket had three stages. The first two were liquid-fueled and the third was solid-fueled. That struck me as odd, as solid fuel engines are almost exclusively used in atmosphere, and you'd ...
4 votes
2 answers
8k views

Calculate Falcon 9 CO2 emissions

Falcon 9 uses Merlin 1 Kerosene based engines. Are there 4 Merlin 1 engines? This seems simple to calculate: Number of Merlin Engines x Merlin 1 fuel capacity(gallons) x Kerosene to CO2 Production. ...
10 votes
3 answers
1k views

A cryo tank within another cryo tank...is it a sound engineering concept?

Here's the idea: A large spherical LH2 tank is placed inside a spherical LOX tank. The reason I thought of this is so the inner tank doesn't need to be insulated. It doesn't need to be a double-...
18 votes
5 answers
11k views

Why doesn’t NASA build its rockets using graphene?

Graphene would be a great material to build a rocket out of. Graphene is extremely thin. One single atom thin layer of graphene can withstand 15 000 000 pascal . A square meter of this material only ...
15 votes
1 answer
3k views

Is it possible to turn rockets without fuel just like in KSP

When playing KSP if you click a Key (A,S,D,W) then the rocket turns without using fuel. I thought that a rocket needed RCS to turn. Is it even possible to turn a rocket in space without using any fuel?...
6 votes
4 answers
3k views

Splitting water quickly to turn a water rocket into a H/O rocket at launch: could it work?

I was just looking at a small but impressive compressed air/water rocket that launches off of a metal rod that runs through the nozzle and spans 3/4 of the length of the rocket. As the team increased ...
9 votes
1 answer
199 views

How exactly does depressurization work in a solid rocket motor?

How does the extinction process actually work in a solid rocket motor? Most people initially always read that once a solid rocket fuel is ignited there is no way to actually stop its operation until ...
13 votes
1 answer
2k views

Does NASA have any rocket options to replace ISS segments?

Roscosmos has announced their ISS partnership will end in 2 years This might have been seen as an indication that the new administration at Roscosmos was in a more cooperative mood. Any such hopes ...
5 votes
1 answer
477 views

Why Did Apollo Smoke Twist When Taking Off?

I've been looking at some references of rockets taking off. I came across the Apollo 14 Saturn V launch and noticed that when the rocket was taking off the smoke coming from around the rocket and from ...
2 votes
2 answers
108 views

Restartable Solid Rocket Motors Through Expanding Throats?

I recall seeing diagrams on a solid rocket motor that could "blow" itself out through suddenly expanding its nozzle, leading to the propellant no long burning or producing any thrust. First ...
9 votes
1 answer
1k views

What is a rocket engine spin up test?

Recently I came across internet about SpaceX's Booster 7 explosion in a ball of fire during an engine spin up test. I searched Google about rocket engine spin up test but I got no hit. What is a ...
31 votes
6 answers
21k views

Why does a rocket engine provide more thrust in a vacuum than in atmosphere?

According to NASA Each Space Shuttle Main Engine operates at a liquid oxygen/liquid hydrogen mixture ratio of 6 to 1 to produce a sea level thrust of 179,097 kilograms (375,000 pounds) and ...
1 vote
0 answers
40 views

Matching reference thrust to engine given certain parameters

I am running a simulation where a reference thrust value is meant to be matched by a liquid engine which I know the following information about: $"F_{vac}=100000"$ N, $I_{sp}=364$ sec, $D_e=1.01$ m, $...
3 votes
1 answer
220 views

European orbital rocket companies?

Besides the obvious Arianespace (France) with Ariane 5/6 Avio (Italy) with Vega/Vega C I found a few other new companies that haven't launched yet (to my knowledge), such as RFA (Germany) Isar ...
2 votes
0 answers
53 views

Dataset of Rocket Launch Data

I needed actual data of any space rocket for a project that I am doing. Information regarding Altitude or trajectory Thrust Sp. Impulse etc was needed at each step of time. It would be great of the ...
7 votes
1 answer
981 views

Is there an ultimate break-even point with rocket nozzle length or expansion ratio in a vacuum?

I know that in an atmosphere, you don't want your expansion ratio to be too high, or it will cause some big problems, and that vacuum engines are restricted by the space they have to fit in, but if we ...
1 vote
1 answer
93 views

What is the difference between a Trans-Mars Injection and a Mars Transfer Orbit?

So I'm using this transfer orbit calculator and when simulating a transfer from LEO to Mars, in the delta-v breakdown, appear two different values: TMI (Trans-Mars Injection), at around 3000 m/s, and ...
1 vote
0 answers
62 views

Liquid propellant rocket engine igniter [closed]

I have a project in which I will have to design a rocket engine igniter. It is for the big scale rockets for space missions. But, there is no information available on the internet regarding the ...
11 votes
1 answer
2k views

What's the typical temperature of a reactor core in a nuclear thermal rocket?

I am curious of the typical temperature of a nuclear fission reactor in a NTR and I heard that increasing temperature could increase Isp but couldn't find any useful data online. Please provide viable ...
4 votes
0 answers
127 views

What is the largest number of rocket engines ever successfully used on a single craft as of 2022?

A fully stacked Starship was rolled to the pad this week for testing. The byline caught my eye, though (emphasis mine) SpaceX moves a massive rocket with 33 engines to its launch pad for tests No ...
13 votes
2 answers
8k views

How does a rocket navigate during launch?

From what I understand, a rocket changes its direction during launch by gimbaling its engines (i.e. swiveling the engine nozzles so the thrust of the engine points in the correct direction). But what ...
2 votes
2 answers
901 views

Which components do we calculate for center of pressure? Where is the distance of components while computing the cp and cg of a rocket?

everybody! I have 4 questions about center or pressure (cp) and center of gravity (cg) of a rocket system. Questions 1) While computing the center of pressure of rocket system, which components do ...
1 vote
1 answer
233 views

Why does igniting propellant provide more thrust?

My confusion stems from the relationship between thrust and the pressure distribution in the thrust chamber. For a given chamber pressure the wall static pressure along the nozzle is a function of ...
6 votes
2 answers
1k views

What are the advantages and disadvantages of using either liquid hydrogen or liquid methane based rocket fuels?

I am working on a near-hard scifi story that mainly involves travel across a single widely populated solar system. I imagine that realistically there will probably be a wide variety of ship designs, ...
5 votes
1 answer
140 views

basis for designing fins of a space launch vehicle

What was the basis for deciding the size, shape, location and number of fins for the Saturn V (or any other rocket for that matter)? Does it have any calculations or were they designed based on ...
3 votes
2 answers
161 views

How would building rockets on other planets and moons influence their design?

John D. Clark's Ignition! says that a frequent problem with choosing propellants has been that they can be very challenging or dangerous to handle, or that they have a high melting point or a low ...
1 vote
2 answers
709 views

How would the rocket differ in a higher atmospheric or ambient pressure?

I imagine the both rocket nozzles in either environment underwater or Jupiter or underground would have to be different than that of standard rocket nozzles because of the back pressure. In this ...
19 votes
4 answers
9k views

Why are rockets cylindrical?

What are the drag coefficients for a cylinder, a wedge, etc? I know there are other reasons for a rocket to be cylindrical that aren't related to aerodynamics such as efficiency when mixing the ...
1 vote
1 answer
164 views

Horizontal vs Vertical Takeoff

What is the reason that some space planes take off with the help of a rocket and others take off with nothing but their own engines. For example the X-37 uses an additional rocket while the VSS Unity ...
24 votes
2 answers
4k views

Why are Starship landings so difficult when SpaceX has landed so many boosters?

Per Wikipedia, SpaceX has landed boosters successfully 79 out of 90 times. Yet Starships seem to be reliably exploding upon landing. What is so different about the two that Starships are so much more ...
8 votes
2 answers
6k views

What is producing the orange-brown smoke in the exhaust of some North Korean missiles?

Accompanying a newsreader's report of North Korea's launch of a new long-range (claimed up to 10,000km) missile is footage of a launch in which the rocket produces clouds of orange/brown smoke. ...
8 votes
0 answers
203 views

Silane as a rocket fuel

At about 6:55 into the video Why Moon Mining Will DEFINITELY Be A Thing it is stated that lunar silica (SiO2) could be turned into silane (SiH4), which is the silicon analogue of methane. It also ...
3 votes
1 answer
570 views

How do Expander Cycle Engines Inject Liquid Fuel During Startup?

My understanding is that the H2 in an expander-cycle engine is vaporized by the heat from the combustion chamber and nozzle wall. This is used to power a turbine and then get injected, in gas phase, ...
8 votes
3 answers
6k views

Ion Thruster Thrust Calculation Problem

Trying to calculate the impulse of a little ion thruster I'm putting together. An old version of it can be found here, I'll be polarizing the AC current and putting in copper nails on the next ...
2 votes
2 answers
258 views

Why does Vandenberg have the most launches?

Why does Vandenberg SFB have the most launches? Is it related to location, when it was founded, something else, etc? It would make more sense for Florida to have more launches. It is illegal for ...
7 votes
4 answers
3k views

What is "aerospace grade"?

I recently asked this question. There, I was also linked to this other question. Both, however, could benefit from the answer to one fundamental point. What is "aerospace grade"? If ...
0 votes
1 answer
193 views

Why aren't clusters of F-15 or SR-71 engines used for a boost stage for rockets? [duplicate]

A cluster of say 8 F-15 or SR-71 engines in my mind could make a viable first stage for a small rocket. Second they can land the stage back to the ground and if my guess is right they could go to up ...
1 vote
1 answer
304 views

How many times has SpaceX reused Falcon 9 first stage until 20th May 2022? [closed]

How many times has SpaceX reused Falcon 9 first stage until now? Not about the possibility. I want to know the current progress with the Falcon 9 first stage.
8 votes
2 answers
588 views

Is engine thrust noticeably increased near the ground?

I know next to nothing about rocketry and space flight. I assume that the majority of the force generated by a rocket's engine is simply the result of throwing gasses out of the bottom very fast, and ...
11 votes
3 answers
5k views

Can we use liquid propellants in amateur rockets?

Is it possible and worth it to use liquid propellants like liquid oxygen and liquid hydrogen in amateur rockets? What are the other types of liquid fuel used? Moderator's Note: Remember discussion ...

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