Questions tagged [rockets]

Questions regarding the boosters or thrusters used to propel man-made objects.

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1answer
39 views

Why alcohol had been selected as fuel for the first American space rockets?

I was surprised to read that Redstone used 75% ethyl alcohol as a fuel. Looks like this idea was abandoned later, and modern rockets use rectified petroleum or liquid hydrogen instead for burning with ...
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1answer
78 views

What size and shape is an SL-16 R/B and for how long will they orbit Earth?

This night I've seen two SL-16 R/B on the sky with my binoculars. These where part of some Zenit rockets that launched satellites in the 90s. They travel at altitudes that double the ISS, uncontrolled....
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104 views

Why aren’t rocket stages modular and interchangeable?

Being an avid player of Kerbal Space Program, it is intensely frustrating to return to the real world and have to remind myself that rocket stages can’t generally be swapped out between rockets (...
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51 views

PID Controller for Thrust Vector Controlling of High Power Rocket

We are trying to design a Thrust Vector Control system for a High Power Rocket using PID Controller. Can anyone guide us what approach should we use to create this Controller? Rocket Details: Mass: ...
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1answer
3k views

What happened to the Apollo 1 rocket?

On January 27, 1967, a tragic fire killed the crew of Apollo 1 and destroyed the Command Module. I've read detailed reports about the engineering team that disassembled the Command Module. I haven't ...
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5answers
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Why doesn't SpaceX land boosters in Africa?

Apart from the obvious answer that it'd take too long to get the booster back across the Atlantic, why doesn't SpaceX leave the main or centre booster in space a little bit longer and guide it to land ...
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188 views

Did the Falcon Heavy center core miss the drone ship or abort?

On the recent Space Test Program-2 Falcon Heavy launch, the center core crashed into the ocean. Unlike the test flight, however, it was not due to running out of TEA-TEB lighter fluid. From the video ...
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5k views

Reusable spacecraft: why still have fairings detach, instead of open/close?

Why do reusable rockets (e.g. SpaceX Falcon 9) still utilize detachable fairings? SpaceX keeps trying to find a way to recover the $6M fairings for obvious cost saving reasons, why not have them ...
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0answers
32 views

How much higher could g be before we couldn't launch rockets? [duplicate]

Obviously having a higher gravitational acceleration makes it harder to get rockets into orbit / escape. How much stronger could earths gravity be before we would no longer be able to do the sort of ...
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1answer
75 views

Why does the RD-180 route the preburner exhaust directly into the LOX boost pump turbine?

Isn't there $\mathsf{CO_2}$ and $\mathsf{H_2O}$ in the oxygen-rich preburner discharge? Why aren't the Russians worried that these two would freeze when the discharge is re-condensed into the LOX ...
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3answers
4k views

Why does the Saturn V have standalone inter-stage rings?

Why are they not integral to the lower stages, e.g. like the Falcon 9? This applies not only to the ring between the first and second stage and also to the shoulder between the second and third stage.
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2answers
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Oxidizer Line Pressure of DIY Hybrid Rocket Engine Limits Thrust?

So I’ve seen engines like these which use gaseous oxygen as an oxidizer and then a solid tube as a fuel. But do these types of hybrid engines have any possibility of creating a useful amount of thrust?...
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4k views

Does anyone recognize these rockets, and their location?

I clicked an advertisement in the sidebar of an Economist article and it took me to this infomercial from Mitsubishi Heavy Industry Group's Spectra website How new technology is democratizing access ...
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1answer
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Testing of a first stage using dummy upper stages?

The first stage of the Saturn I was tested three times using dummy upper stages filled with ballast water, see Project Highwater and this question. The first two flight tests of the Saturn V (SA-501 ...
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1answer
48 views

GLOM of a launch vehicle

What do you mean by GLOM of a launch vehicle? When I googled about it, it says it is a type of mass but I am unclear about it.
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Exit pressure value for vacuum nozzle [duplicate]

What value of exit pressure should I use in the design equations for a small liquid rocket engine nozzle for 200km-500km operating conditions? Since using zero as a value is not possible or else ...
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1answer
113 views

Apollo SM RCS specific impulse?

What is the specific impulse of the RCS thrusters on the Apollo Service Module? This document cites 281 seconds for the LM's RCS thrusters, but I cannot find similar specs for the SM.
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1answer
99 views

Rocket Launch Simulation Source Code Locations

As you can take from the title, does anyone know where I could find the source code for a working launch simulation type application such as FlightClub for example?
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1answer
232 views

Why is multi-spool pump very rare on rockets?

The only one I know of is the LP LOX pump on RD-0120. A multi-spool design is already a default for jet engines, which are basically turbine-driven air pumps. A multi-spool pump can save at least the ...
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1answer
263 views

Why were Spirit and Opportunity separate launches?

In reading this question (Why A=2 and B=1 in the call signs for Spirit and Opportunity?), it prompted me to wonder why Mars probes Spirit and Opportunity were launched separately, even though their ...
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3answers
278 views

Just how pointy does a rocket's nosecone need to be?

There are some beautiful images of the Qu8k rocket launch on this web page and I show a few below. There's a video (below) and the PDF Qu8k Final By Derek Deville, November 27, 2011 The stainless ...
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2answers
102 views

Why isn't there a rocket to launch a single cubesat?

I find the business model for RocketLab interesting. It is said that they fill a niche in the market by using smaller rockets. And it is true, in comparison to e.g. Falcon 9's payload of 9,500 kg, ...
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1answer
167 views

Why we don't use cyclotron for ion thrusters?

We know that the advantage of thruster is high efficiency and 'everlasting' propulsion. Which It can not provide a sudden huge propulsion during launch like chemical fuel is its biggest problem. I ...
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40 views

How does the inter-propellant seal works in kerosene/LOX and UDMH/NTO rockets?

I get that the inter-propellant seal on the SSME LOX HP pump is simply a series of cascading regular seals trying to eliminate bleed-through by venting and letting boil at each stage, so that when ...
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43 views

How much more hardware is needed in a cross-fed CBC rocket than a non-cross-fed one?

Is it just a matter of adding a multi-in fuel manifold?
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2answers
364 views

Have there been any examples of re-usable rockets in the past?

I am writing a piece about re-usable rockets and I'm wondering, apart from SpaceX, have there been any re-usable rockets in the past, success or 'failure', as in didn't perform as expected. Obviously ...
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286 views

Why is SpaceX's Raptor's design so simple in comparison to SSME?

What is especially striking to me is how simple Raptor is in configuration compared to SSME. The Raptor doesn't have an LP fuel or oxygen pump. What's even more surprising, if we are to compare the ...
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2k views

Is it possible to create different colors in rocket exhaust?

Would it be feasible in any rocket engine (liquid or solid) intended for flight above the atmosphere to add one of the following elements: barium, lithium, sodium, copper, or calcium to create ...
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1answer
120 views

Is the gyroscopic effect created by high rpm turbo-pumps an issue for rocket attitude control?

Is the gyro effect taken into consideration in the control strategy or is it somehow mitigated?
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1answer
208 views

Why is LOX on top in the Space Shuttle external tank instead of the other the way round? [duplicate]

Why is oxygen placed on top of hydrogen? Does this have anything to do with letting the warmer and not the colder liquid have a non-spherical bulkhead and thus more surface area to reduce boil-off?
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1answer
117 views

How is the height of a rocket measured?

How is the height of rockets measured? For example, the Saturn V is 363 feet tall, but is that 363 ft from the tip of the launch abort tower to the bottom of the engine bell or is it from the tip of ...
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1answer
213 views

Why did the Americans abandon kerosene after F-1 while the Soviets continued to develop it to very high sophistication?

What is the reason behind America's switch to LH2/LOX, and (USSR's) Russia's decision to stay with it and develop it to spectacular technical sophistication such as the Oxygen-rich staged combustion ...
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1answer
95 views

What kind of methane-fueled rocket engines exist?

I have heard of methane being a strong contender for Mars and beyond. Methane is a cryogenic fuel and is said to have a high specific impulse, and work with closed- and open-expander cycles. I have ...
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1answer
137 views

When Falcon 9's stage 2 engine fires up, does the flame of the engine affect stage 1 in any way?

Are there any specific design considerations that are made over nonreusable, traditional rockets to tolerate the blast from the stage 2 engine? As shown in this moment:
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1answer
175 views

Is Cryogenic Rocket Fuel Still Liquid When It Flows Through a Regeneratively-Cooled Nozzle?

For a rocket engine that runs on (deeply) cryogenic fuel like LH2, e.g. SSME, is the fuel kept liquid throughout the entire length of the regenerative cooling circuit in the nozzle? Or is it allowed ...
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3answers
119 views

Stability of rocket during flight; why does the lift force change direction when the center of pressure moves?

I am currently learning about fins and the role they play in the stability of a rocket during flight. I came across a relatively minor problem. Here is one of the resources I'm looking at: http://www....
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73 views

Books on Vertical-Landing Vertical-Takeoff (VTVL) of Rockets? or Rocket Design in General?

I am working on a rocket control system design and I am trying to understand the the fundamental principles and concepts to design an efficient controller for recovering and landing the rocket, ...
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1answer
35 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 ...
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3answers
260 views

How much of a rocket's energy is used to achieve altitude vs horizontal velocity?

Given how it is significantly easier to achieve suborbital spaceflight, I was wondering about how a rocket spends its energy budget. If you magically could launch a rocket from 0 km/s but from an ...
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2answers
141 views

Why use thrust control systems rather than fins?

Why do large professional rockets like those from SpaceX use thrust control systems to steer the rocket instead of fins? I know they both work, but it just seems that the thrust control requires more ...
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Lightest possible orbital rocket - being launched from high altitude

Iv'e been looking into micro-satellites launches on small rockets - from what I could find the lightest rocket to deploy a satellite into LEO is the SS-520-4 which had a weight of 2600kg. If ...
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235 views

how reusable are electric pump fed rocket engines like Rutherford Engines of Electron rocket?

In electric pump fed rocket engines, propellants are pumped by two electric motors. So there is just one combustion chamber and that is the main combustion chamber. I guess electric pumps are fairly ...
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1answer
86 views

High altitude balloon + rocket [duplicate]

I heard that most of a rocket's power is used to get out of the atmosphere. So I was wondering if it would it work to send a very low powered rocket (maybe even something that was simply shot using ...
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1answer
99 views

Ambient pressure for vaccum nozzle design

How do I find out the ambient pressure for designing a vaccum rocket engine? I am using the propellant combustion charts from the braeunig website. But I cannot figure out the ambient pressure for ...
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1answer
209 views

Super Capacitor Stages

Could this super capacitor be up scaled to be of use in the lower stages of a rocket? Here is the only information I found online on this? Related: Could rockets ...
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1answer
44 views

What channel does a launch vehicle telemetry system see? Is it AWGN?

What is the kind of channel seen by a communication system (for telemetry data) on-board a launcher during various phases of launch. Is it a fading channel or AWGN channel? (Additive white Gaussian ...
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2answers
306 views

What is the most expensive part of a rocket?

I want to say fuel is, but this Question Why isn't stainless steel used for rocket engines? has got me thinking about cost in the long run. What part commonly found on most rockets cost the most ...
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3answers
241 views

How good is Stratolaunch vs Falcon9 as a first stage?

With the Stratolaunch flying this week I was interested in seeing how good it was compared to a Falcon9. I figured comparing energy contribution would make sense. The stats as best I can find: ...
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What is the physics behind a rocket landing on a celestial body with an atmosphere?

I would like to know the different physics concept I would need to land a rocket being in orbit. I know the timing is important to leave it, how can one find this out ? Then how to compute the ...
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1answer
153 views

Can Amateur Rocketeers use Liquid Nitrogen Dioxide as oxidizer?

I was reading similar question as mine here. But no one talked about Nitrogen Dioxide (NO2). Its boiling point is 21C. So easy to store. But how easy it is to handle compared to Hydrogen Peroxide or ...