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Questions tagged [engines]

Questions regarding equipment used to propel a spacecraft or a rocket. Questions about attitude control jets should be tagged "attitude".

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Solar preheated magnetoplasmadynamic thruster

Can focused sunlight super heat the gas in a MPD taking less electricity to change the fuel into plasma? From comments: http://www.projectrho.com/public_html/rocket/enginelist.php#id--Beamed_Power--...
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Why does Orion's Jettison Motor, have four nozzles but eight Attitude Control Motors arranged in an octagon?

Spaceflight 101's Orion Spacecraft Overview shows the following tests for the escape system. Why are there eight ACS thrusters arranged octagonally? Is it just to reduce cosine losses or does this ...
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1answer
205 views

NASA's RS-25 Engines

I am developing a FSX-based space flight simulator FSX SpacePort. I've been trying to get the detailed specs on NASA's RS-25 engine, namely, what were the ramp-up times for this engine? As in, how ...
2
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1answer
89 views

How do you determine what the temperature will be in the combustion chamber of a rocket engine?

I am guessing it is dependent on the fuel and oxidiser and the chamber pressure but is there an equation that would calculate the chamber temperature?
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1answer
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Weight Flow Rate

I read in the book INTRODUCTION TO ROCKET SCIENCE AND ENGINEERING by T.S.T that Rocket Engineers design how big the throat of the nozzle should be based on the Weight Flow Rate. So my question is HOW?
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1answer
105 views

What is a raptor engine manifold and what's happening in these tweeted pics?

When I think of the words "engine manifold" I think of these. I saw this tweet by Elon Musk which shows the image below, and then there is a reply image with a checkerboard pattern behind part of the ...
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2answers
63 views

Relationship between propellant mass and thrust at relativistic speeds

When answering this question about relativity and delta-V I realized I don't know the relationship between the mass of propellants and how much delta-v they would produce in an engine at relativistic ...
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1answer
19 views

How do you read an Engine Throttling specification of 3-5:1 in percent thrust load?

I was looking at the CECE engine by Aerojet, however I am not sure how to determine the trust range of percent thrust range of the engine. How I can translate the throttling spec into a percent load ...
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2answers
79 views

Is there an upper stage main engine that is human ratable and may out perform the Common Extensible Cyrogenic Engine performance by Aerojet?

I am fasinated by Aerojet. The CECE, has a total qualified burn time of 10,000 seconds and with a total of 50 restarts. The LOX/LH2 engines have a great performance with a specific impulse of > 445. ...
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1answer
101 views

Is a kilowatt per square centimeter a typical launch engine's thermal energy flux (density)?

I saw the following image while searching for this answer in Sung Hwan Kim's thesis Germanium-Source Tunnel Field Effect Transistors for Ultra-Low Power Digital Logic It plots power density in Watts ...
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1answer
143 views

Advantage of full-flow staged combustion vs conventional staged combustion engine

Referring to the question in this thread. What is the advantage of full-flow staged combustion (FFSC) vs conventional staged combustion rocket engine? In FFSC we feed the full volume of fuel and ...
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1answer
89 views

What's the smallest kerolox engine that is/was used for spaceflight?

This comment linked in this answer to the question How does the camera make the exhaust of the Electron's RP-1/LOX exhaust transparent? says Some quick calculation suggests the thickness of the ...
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2answers
152 views

Is presssuized gas absent in a turbopump-driven rocket engines?

For RL-10 rocket engines, are the propellent pumps able to provide the propellent without a source of pressurant gas?
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0answers
39 views

What main engine used in a series of environmental satellites has failed more than once (according to the GAO)?

A GAO report on NASA's ongoing projects can be found here. On page 70 while discussing the Lucy mission, it says the ... main engine was the same model used on a series of environmental ...
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1answer
63 views

How does the chamber pressure affect the performance of a Rocket Engine?

I am under the assumption that higher chamber pressure results in increase in exhaust velocity. Is this true?
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1answer
532 views

Crew Dragon SuperDraco Engine Covers

(Source: Nasa Spaceflight article) While looking at the new images of the upcoming crew dragon launch I noticed a distinct lack of holes in the part of the dragon the Engines are supposed to be in. ...
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1answer
4k views

What are the 'lights' inside Shuttle main engines at landing?

I have a night-landing photo of the Shuttle showing lights (I assume some type of glow-plug to burn off extraneous fuel). My understanding is that only the OMS engines burn to begin reentry. Can ...
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241 views

Why isn't stainless steel used for rocket engines?

Most people have probably heard by now that Elon is changing Starship to a complete stainless steel build. Anyways, it got me thinking, why isn't stainless steel ever used for rocket engines (nozzle, ...
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3answers
4k views

Why was the engine of the launch vehicle recently tested in Iran “not a very good missile engine”?

The NPR News item What's Iran Up To With Recent Rocket Launch Attempt? by NPR's Geoff Brumfiel, about a recent launch test in Iran includes the following: Earlier this week, Iran attempted to ...
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1answer
139 views

Why not turn off the main engines while using the launch escape system on liquid fuelled engines?

I've seen a couple of launch escape systems firing and the rockets main engines are on, isn't it more safe if you turn off the engines? Edit: i agree that the engines turning off might be not so ...
3
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1answer
80 views

The changes of a throttled Merlin-1d engine

With Merlin-1d being able to throttle down from its full thrust potential, this post about its throttle capability does not mention much of its change in performance. On the Wikipedia page of Merlin-...
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1answer
163 views

How often has (or how common is it for) the ISS's orbit been propulsive lowered intentionally?

The question Which engine worked the hardest to keep the ISS in orbit? laments the tireless efforts to keep the ISS from falling from the sky by regularly executing propulsive orbit-raising maneuvers. ...
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1k views

Can a Soyuz-MS still propel itself back to earth if all its Hydrogen Peroxide decomposed?

In this answer it is stated that: If the fuel fully decomposes then return to Earth is still possible but only via ballistic descent I find it a little bit surprising, but maybe there is enough Δv ...
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1answer
142 views

Why is the engine configuration of the Mitsubishi H3 rocket designed to be off center?

Here is a diagram from a recent Ars Technica article about the H3: You can see at the bottom that the main engines are not 90 degrees off from the side engines. I'm sure that this has been accounted ...
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109 views

What is the best fuel for bottle rocket? [closed]

I want to modify my firework bottle rocket to fly a mile high. What will be the best fuel for this? Could fuel used in space rockets be scaled down to work in a large bottle rocket?
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2answers
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What are some notable cold gas thruster propellants, and why?

Cold gas thrusters are a very simple and reliable form of thruster that operate only by spraying a compressed gas, without any chemical reaction. What are the most common, performant, or otherwise ...
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Quantitative plots of v, T, p, vs position from chamber through nozzle to ambient for a few canonical modern engines?

In this answer I showed the schematic diagram of a basic de Laval nozzle and representative plots of how temperature, pressure and and velocity would behave. It can be used as a rough representation ...
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1answer
37 views

Achieving relativistic speeds by lasers

Basic data about our spacecraft: Basically were using a laser as an engine. Mass: 1000 Tons Electrical Power for the laser: 10 GW Efficiency of the laser(s) : 50% So first I calculated the kinetic ...
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5answers
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Falcon 9: engines stabilize spin

On CRS-16, the landing Falcon 9 booster entered a spin rotation due to a stalling grid fin hydraulic pump. According to Musk, the engines stabilized the spin. How is this possible? The main engines ...
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2answers
287 views

What are these flames on the Falcon 9 booster?

When Falcon 9 was on its way to ascend, flames appeared around the bottom of the booster. What are they? It seems to begin around about 20:36 in the video, ...
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1answer
610 views

Have all of InSight's engines/thrusters been permanently disabled now that it has landed?

One aspect of InSight's condition that may be helpful to formulating an answer to the question Could InSight lift off and move somewhere else? is the current status of InSight's propulsion system. ...
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What is an “M motor” used in a full-scale model of a Corporal missile?

The NASA JPL video Corporal: America’s First Guided Ballistic Missile shows that it used an Acid/Analine engine. That would have been both challenging and unpleasant to reproduce. So instead, the ...
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How are Voyager's 16 thrusters oriented?

@RussellBorogove's excellent answer to the question How do Voyager 1's Trajectory Control Thrusters differ from its Attitude Control Thrusters? describes the locations and usage patterns of the 16 ...
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Problems with shutting off “torch igniter” during the operation of combustion chamber

With reference to the presentation pp 76, where SSME's Augmented Spark Igniter is said to have their flame "On" even after the main combustion chamber ignition, is to prevent the blowback from the ...
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3answers
2k views

Why do chemical rockets encompass a weird shape on this thrust vs. Isp graph?

Consider this graph of engine thrust versus specific impulse (from https://dawn.jpl.nasa.gov/mission/ion_prop.html): Most propulsion technologies encompass roughly rectangular regions on the graph. ...
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Purging process of a rocket engine

Does spacex purge Falcon 9 engines after landing ? If so, which gas is used for purging?
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1answer
980 views

Why is a purging process necessary for static firing test of liquid rocket engines?

In Chapter 7 of Modern Engineering for Design of Liquid propellant Rocket Engines by Huzel and Huang, mentions the following engine cut off procedure. The cutoff sequence usually consists of ...
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1answer
104 views

Has the use of any commercial launch vehicle's engines on an unrelated vehicle ever been seriously considered?

When reading On the Cusp: What’s NextDARPA Perspective on Space Briefing prepared for 53rd Robert H. Goddard Memorial Symposium March 12, 2015 I saw the slide shown below. The slide's heading is ...
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1answer
275 views

How does falcon-9 engine survive while re-entry burn without chilling ?

I've often seen that in launch sequence, "engine chilldown". I've learnt that chilling is done to avoid thermal cracking in plumbing lines and also to avoid cavitation. While re-entry, do they ...
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1answer
255 views

What is the highest gimbal range ever used on an engine?

This answer here mentions the STS-94's ability to gimbal up to 20 degrees in all directions, that got me thinking, what exactly is the maximum ever feasibly implemented? I've seen a lot of information ...
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1answer
161 views

How are rocket propellants ignited repeatedly without the ignition source melting

I know that SpaceX's Falcon uses TEA-TEB instead of a physical igniter, but if I remember correctly, NASA has never used hypergolic propellants to start their restart-able engines. How does NASA's (or ...
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1answer
167 views

What is the inner wall of the thrust chamber made of?

With advancements in additive manufacturing, the manufacture of regeneratively cooled thrust chambers is simpler nowadays. Brooklyn based startup Launcher Space Inc. says most 3D printed engines use ...
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1answer
272 views

Why are 22N and 440N liquid engines quite common?

One can often spot that liquid apogee engines are 440 N and attitude control systems are 22 N. Is there a reason why the thrusts are proportional? If the engines are scaled for reducing development ...
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350 views

Why is the exhaust plume of Falcon 9 upper stage shaped the way it is?

The (single) Merlin 1D vacuum engine's exhaust plume has a symmetric shape, comprising of six distinct "inner" plumes. Why does it have this shape? Is it due to the shape/configuration of fuel ...
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148 views

Was Jules Verne the inventor of the retro-rocket?

In his novels 'From the Earth to the Moon', and 'Around the Moon', Jules Verne writes about a set of rockets fitted to the spacecraft he imagined, that were intended to be fired in order to slow down ...
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1answer
115 views

How large is a magnetoplasmadynamic (MPD) thruster? Are there any upcoming programs using it?

Magnetoplasmadynamic thrusters are an interesting proposed method for propulsion in space, but are there any upcoming programs that will use them? If not, might this be because there still serious and ...
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70 views

Where can I read further on the specs the South Korean engine for next month's sub-orbital test?

Ars Technica's weekly installment of Rocket Report: SpaceX gets Moon launches, South Korean rocket, BE-4 wins says: South Korea to test first-stage engine. The Korea Aerospace Research Institute ...
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1answer
176 views

What may be the condition of the first stages of Saturn V splashed into ocean after separation?

Two F-1 engines were recovered from a depth of 14,000 feet (4,300 m), about 400 miles (640 km) east of Cape Canaveral after 40 years in the ocean. There is much damage caused by splash down but very ...
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51 views

Nozzle extension(skirt) attachment mechanism

I am looking for the nozzle skirt attachment mechanism, for RocketLab it looks like nuts and bolts and for SpaceX I don't have any idea. If anybody have any reference for what mechanism should be ...
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1answer
132 views

How common is the ability to compensate for a lost engine through gimbaling?

Discussing a system of regulating thrust through lighting/extinguishing engine pairs, I was met with a reply: Really there is no need to treat engines as a pair in this context. In fact, ...