Questions tagged [rockets]

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

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21
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4answers
6k views

Advantages of launching very large rocket while submerged, buoyant, in a body of water

I vaguely remember reading about some supposed advantages of launching very large rockets (Saturn size and larger) from underwater in an ocean or similar large body of water. I was recently reminded ...
36
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7answers
7k views

How much stronger does gravity have to be for space travel to be impossible? [duplicate]

I’ve heard that only a slightly stronger gravitational pull would make it impossible for rockets to launch. Is this true? I’ve heard this used as the reason why humanity is meant to be in space.
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0answers
60 views

How are rocket launches scheduled?

With all the satellites and other objects already in space; how exactly are launches scheduled and coordinated? Is there some kind of clearinghouse? How do the mega constellations affect the ...
6
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0answers
135 views

What are these wires on the side of the SLS core stage?

I was reading about the SLS core being moved for testing and I noticed something odd on the core stage. There's several lines on the stage, which in closer inspection are wires. It's not obvious what ...
8
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1answer
155 views

Where are the lost RS-25D Block 2 engines?

There were 21 RS-25D Block 2 engines made. Two of them never flew. Three of them were lost with the Columbia disaster. 16 of them are tagged for SLS's use, including 14 previously flown, and the two ...
2
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0answers
144 views

Cost of launch unrelated to cost of building rocket

ULA CEO Tory Bruno said long time ago that only 1/2 cost of orbital launch is cost of building of rocket. SpaceX never denied this. F9R block 5 total cost of launch can be about 60-80 million per ...
1
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1answer
162 views

Given unlimited funding and global cooperation, could there have been a manned space craft made in the year 1850-1860? [closed]

All my life, I've been speculating in my head about all kinds of "alternative timelines". One of the most intriguing to me are all the ones that concern space and "steampunk" technology. Recently, I ...
2
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0answers
25 views

Ares 5 and SLS relation [duplicate]

I'm having an online discussion regarding these rockets. I'm being told that I'm wrong to think of the SLS as a continuation of the Ares 5. That the SLS is a completely different rocket, and so it's ...
6
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1answer
82 views

Gravity turn: How to reorient along zero angle of attack

I was doing some back-of-the-envelopish calculations on gravity turns. Now the basics are clear to me (I think), but this detail escapes me: After liftoff we perform pitchover manouvre at time T+x, ...
8
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1answer
2k views

Is it possible to build a rocket with 2kg payload? [duplicate]

Is it possible to build a small rocket that carries 1 cubesat into orbit? And how small the rocket would be, if it is possible?
8
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0answers
89 views

Were there any launch vehicles with so heavily pronounced Plume Induced Flow Separation (PIFS), other than Saturn V?

This answer describes a very interesting phenomenon of Plume Induced Flow Separation on Saturn V vehicle. (Apollo-6 S68-29737 photo, courtesy NASA) This is, basically, when "fire" from engine ...
1
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1answer
93 views

Help on Nozzle Throat Area Calculation

This is the equation of the nozzle throat area This equation is based from a book called HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES This is the solution The problem is I don’t ...
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0answers
47 views

What is the white vapor seen immediately prior to and during the early part of the launch? [duplicate]

As most modern rockets rest on the pad much white vapor is seen. Is this propellant being vented or condensation from the surrounding air due to the extreme cold of the rocket body?
5
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1answer
155 views

What was the first rocket with de Laval (convergent-divergent) nozzle to fly?

Rocket engine Wikipedia article states that Goddard was the first to use a De Laval nozzle on a solid-propellant (gunpowder) rocket engine, doubling the thrust and increasing the efficiency by a ...
1
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1answer
175 views

Confusion about reactive force of a rocket

I am confused about the equation describing the reactive force of a rocket. I read from this source this equation: where M is mass of the rocket, u is the velocity of exhaust gas in an inertial frame ...
1
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3answers
263 views

When is a rocket a rocket?

A comment was offered in this question, how technically soft landing works without air on the moon?, asking "what do you mean by 'rocket'." This brought to mind the question of what is a rocket. Does ...
4
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3answers
2k views

How does a soft landing technically work without air on the moon?

I am curious to know about how rockets or an object lands on the moon when there isn't any air (atmosphere) and the gravity is low.
11
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1answer
983 views

What is the density of supercooled LOX at −206 °C, as SpaceX uses it

I want to calculate the size in cubic meters of Starship's propellant tanks. The only figures for LOX I can find are at −183 °C. 1141.7 kg/m³ at −183 °C. Could somebody please calculate it at −206 °C,...
4
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1answer
130 views

What's up with the lack of subminiature chemical rockets?

Not long ago, I was researching the scaling of converging-diverging de Laval nozzles to subminiature (1.5 mm throat diameter) dimensions for a non-rocket application, and later on studied the ...
1
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0answers
81 views

Can we use a drone instead of rocket? [duplicate]

I would like to know if it is possible to use a drone instead of the rocket to launch a satellite into orbit. If no, then I would like to know why, and if yes, then in which countries would this be ...
6
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0answers
134 views

Are DUMBO, TIMBERWIND, and other high-thrust NTRs realistically going to deliver on promises of very high thrust/weight?

Nuclear thermal rockets (NTRs) are notable as the most mature technology (the second-most-mature is Project Orion) to provide both high thrust and higher specific impulse than chemical rockets. But "...
6
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2answers
1k views

Can a VASIMR Plasma engine be used to launch a rocket?

When I was in primary school, I spent countless hours designing spaceships that probably wouldn’t work. It’s only now that I’ve stumbled across some of the old drawings and actually thought if it ...
3
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1answer
129 views

LANTR has been proposed; why not bilateral CHEMANTR?

Normal solid-core nuclear thermal rockets use a nuclear reactor to heat gas (almost always hydrogen, since higher molecular weights cause miserable performance) and expand it through a converging-...
0
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1answer
154 views

Need help with 'Tsiolkovsky's Rocket Equation': What's the maximum weight of my rockets command module?

A civilization wants to transport a command module towards another planet that is passing by. Their planet has a radius of 6'800 kilometers and weighs about 9 × 10^24 kg. They have no stronger engines ...
1
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1answer
62 views

What is the purpose of the pairs of cylinders on the interstage of PSLV?

In the following images, it can be seen that the interstage (separating the first stage PS1 and the second stage PS2) of the Indian Space Research Organisation's (ISRO) Polar Satellite Launch Vehicle (...
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0answers
55 views

Relationship between scaling up rocket, adding more engines and pressure inside tanks, feedlines

So can anybody say, what is relationship between scaling up rocket ( more payload to orbit ) adding more engines and pressure inside rocket tanks, feedlines. What is standard pressure inside F9R 1st ...
2
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2answers
164 views

At a height of 100 km, what speed do you need to be going to escape Earth's gravity?

I understand that the escape velocity of Earth is 11 km/s. However, Earth's gravitational sphere of influence is not infinite, so it is possible to go slower than that and still escape the sphere of ...
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0answers
64 views

Shuttle main engines RS-25 refurbishment/material damage

There was some thread here on Space Stack-Exchange about RS-25 refurbishment, but I am interested now, how this refurbishment look from the point of material damage of SSME hardware. In the early ...
3
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2answers
134 views

Static forces on a rocket engine

I am trying to understand where and how the thrust forces act in a rocket engine. I had assumed that the net thrust could be "ball-parked" as the chamber pressure multiplied by the throat area, but ...
10
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6answers
4k views

Is it possible to use gases instead of liquids as fuel in a rocket engine?

Im reading about rocket engines and I have a question about is it possible to use fuels in the form of gases than a liquid in a rocket engine?
2
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1answer
128 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"...
2
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2answers
496 views

Velocity of a rocket needed to get to Mars

At 2:16 in this video, Don Pettit says he used the Rocket Equation to determine the velocity of the rocket needed to travel to Mars, which was 16 km/s. I am not sure as how he did it though, and was ...
0
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2answers
108 views

Looking for figures for contemporary interstellar engine options

So I have already done... a lot of reading on this subject lately. A lot. You wouldn't believe. My maths is... functional, probably far above 'average', but when it gets into the realms of the 'rocket ...
28
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6answers
7k views

Would rocket engine exhaust create pockets of gas in space which could hinder further space exploration?

Suppose we establish a moon base. This base would have some population, with some need for supplies, and needs for machinery in the early stages. If we establish shipping lanes in space for these ...
2
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1answer
114 views

How to find the optimal launch trajectory for a rocket launched from a planet with an atmosphere?

I originally asked this question on maths stack exchange As the title states I am trying to find the optimal launch trajectory for a rocket launched from a planet with an atmosphere (Earth) in order ...
13
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3answers
2k views

Why do we need dedicated launch vehicles for small satellites?

The Wikipedia webpage on Small-lift launch vehicle gives a huge list of dedicated launch vehicles with a maximum payload capacity of 2,000 kg (4,400 lb) for small satellites, which are either retired,...
2
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1answer
76 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, ...
2
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0answers
24 views

What's the most optimal method of motor attachment for Horizontal Static Fire Tests?

I'm a college student new to rocketry, and am working on the horizontal test structure for a static fire test of our motors. The max thrust for the booster motor is about 6000 pounds, and the ...
21
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3answers
5k views

Why is the Falcon Heavy center core recovery done at sea?

Why does SpaceX attempt sea recoveries of the Falcon Heavy center core instead of staying at altitude and performing a land based recovery at a different site?
2
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1answer
90 views

Grossly overexpanded nozzle?

How do we classify a nozzle to be grossly overexpanded in the design phase? For example, looking at the dimensions and operating at sea level, can we determine if it will be overexpanded or grossly ...
4
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0answers
52 views

Is there any work in English that gives a systematic treatment of Soviet/Russian rocket engines?

There seems to be some piecemeal information online such as RussianSpaceWeb.com, and of course, Sutton's History of LPRE gives an anthropological treatment of Soviet/Russian rocket engine lineup ...
4
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2answers
299 views

Is there a list of world wide upcoming space events on the web?

Is there a list of all the international upcoming events like launches, expected arrivals at, and landings on celestial bodies, etc. on the internet ?
23
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2answers
5k views

Is the mass of paint relevant in rocket design?

(Prompted by this answer): Do the designers of large rockets* (have to) take the mass of the exterior paint into account? If so, do we have examples of actual design changes/decisions based on this (...
20
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2answers
2k views

Do liquid propellant rocket engines experience thrust oscillation?

I know SRBs have a quite bit of thrust oscillation, and it's pretty much part and parcel of burning solid propellant. Do liquid-propellant engines experience something similar albeit at a much smaller ...
2
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1answer
124 views

Does any US rocket, historical or current, besides those using LH2 as fuel apply thermal insulation for propellant?

Besides those using LH2 in a booster and/or sustainer stage, that is. EDIT: I should have made it clear that this applies to launch vehicles, not spacecrafts flying deep space mission. EDIT: OK, I ...
3
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0answers
107 views

Why is the relative axial position of oxidizer vs fuel tank inverted in the upper stages of most rockets?

In the first stages of most rockets, e.g. Atlas V, Delta IV and Falcon 9, the oxidizer tank is stacked on top of the fuel tank, with the usual explanation that such an arrangement gives the rocket a ...
1
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1answer
136 views

How do control space launch vehicles ? Automotivelly (inbuilt commands) or from ground level?

In my perception, by predetermining speed, distance and other parameters including a rocket's thrust and mass, a trajectory could be calculated ahead of time.
5
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2answers
136 views

Can anyone give feedback on the following design system architecture for the electrical component of a rocket test stand?

My rocketry team and I are currently designing the system architecture for the electrical component of our rocket test stand for a static fire test. We have not started implementing this and I would ...
1
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2answers
149 views

How to shoot a raspberry pi mini computer into orbit

I'd like to shoot a raspberry pi into orbit. How difficult is this and is this something that could be achieved by hobby rocket scientists?
23
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2answers
4k views

Golfball Dimples on spaceships (and planes)?

The best of us get stupid ideas which run through our heads day in and day out without finding an answer. That's why I came here: A golf ball has dimples to reduce drag and increase flight distance (...