Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [rockets]

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

16
votes
0answers
356 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 ...
9
votes
0answers
187 views

How far have autophage rockets been developed?

Ars Technica reports on a May 24 phys.org press release/precis on a University of Glasgow paper in Journal of Spacecraft of Rockets about a solid rocket intended to consume itself during use rather ...
9
votes
0answers
255 views

What were some of the first two stage rockets flown?

The first US two stage rocket was bumper, a combination of a german V2 liquid fuel rocket with an US second stage. The Soviet Union had the R-1 and R-2 based on the V-2. In this list, the R-7 is the ...
7
votes
0answers
242 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, ...
7
votes
0answers
194 views

Convective heat transfer on rocket during ascent

I'm looking for a way to (very) roughly estimate the convective heat transfer onto a rocket hull during atmospheric ascent (ideally through different planetary atmospheres). While I'm comfortable with ...
6
votes
0answers
138 views

Why aren't injector pumps used in rockets?

Is there something that makes injectors unsuitable as oxidizer pumps? Seems to me that rockets would benefit significantly from a pump with no moving parts that runs off its own exhaust.
6
votes
0answers
2k views

Propellant mass calculation

I have been given the following problem: To solve it I used the formulas: $v_e = I_{sp}.g_0$ $M_{propellant} = (e^{\Delta_v/v_e} - 1).M_{final}$ And I assumed that the apogee kick manoeuvre was ...
6
votes
0answers
404 views

What would be the range safety for vertically landing over land rockets?

sideFrom the Wikipedia article on range safety: Rockets are usually launched into a space above the launch range called the launch corridor. If rocket engines fail while the rocket flies inside ...
5
votes
0answers
75 views

Russian Soyuz MS-09 Launch - back and forth rotation of the second stage (along the length axis). Precession?

In the ISS Expedition 56-57 Launch of Russian Soyuz MS-09, in the first view from the external camera at around 3:30, an obvious back and forth rotation (along the length axis) of the rocket can be ...
5
votes
0answers
1k views

Potential improvement to BFR or New Glenn if equipped with aerospike exhaust on their engines?

Aerospikes basically tackle the issue of the variability in required expansion ratio for a rocket engine to be efficient at a given altitude. A recent example though mired in legal issues is a small ...
5
votes
0answers
148 views

Is the variety in the Delta rocket family the result of an artisanal rocket industry?

Between the years of 1980 and 1990 the McDonnell Douglas company supplied at least 10 different variants of the Delta rocket family. Some of these were considered to be Delta rockets while some were ...
5
votes
0answers
326 views

Deriving the thrust of a rocket

I understand the the thrust of a rocket is given by $$F_x = M_e V_e - M_i V_i + (P_e - P_i) A_e$$ However when I try to derive it myself using Reynold's transport theorem I get the following: ...
5
votes
0answers
295 views

Are there any benefits on Venus compared to Earth with respect to reusing launch vehicles?

My assumptions around building up infrastructure for dealing with space launches from Venus assumes colonization based on the principles outlined by Geoffrey A. Landis of NASA in paper Colonization of ...
4
votes
0answers
52 views

How do international students attend the SA Cup sounding rocket competition?

How do the international students carry the rocket along with propellants to this competition, if Airport Authority does not allow flammable substances?
4
votes
0answers
52 views

Why doesn't a regeneratively cooled engine crack due to differential expansion induced by thermal gradients?

A liquid rocket engine with regeneratively cooled chamber walls and nozzles would definitely be one among those components experiencing the steepest thermal gradients (Chamber wall inner - $3000 K$ ...
4
votes
0answers
70 views

How much would mass-production impact the cost of solid-fuel rockets?

Let's imagine that, for some arbitrary reason, solid-fuel rocket stages were needed and built en masse in factories, like planes or even like cars. How much would it drive down the cost of an ...
4
votes
0answers
68 views

Marman vs collet seperation mechanism

The Marman and the Collet mechanisms are used for stage separation in rockets and launch vehicles. Which of these is most efficient, cost wise, weight wise and ease of usability wise? Which of the ...
4
votes
0answers
149 views

What would be the implications of high-altitude or catapult launch for orbital rocket?

There are lots of questions on here which ask "Why aren't rockets launched from railguns/mountains/balloons/etc." and lots of nice answers mainly dealing with the practical difficulties of doing so, ...
4
votes
0answers
175 views

The Shape of a Rocket

What is the shape of a rocket? My English teacher has challenged me with that question and I am not sure of the answer. My friends suggest 'polygon' but I believe the answer is a little more ...
4
votes
0answers
166 views

From a strictly engineering standpoint, would Venturestar have worked as an SSTO?

In looking at the questions here and here, I'm wondering - was the VentureStar platform doomed from the start (in ways nobody could foresee), or was it only the cooling problems with aerospike engines ...
4
votes
0answers
145 views

Mathematical reasoning behind pe=pa leading to maximum thrust

I've been looking at both the thrust and thrust coefficient equations (below) and I understand that they will be optimum in a vacuum when $P_a=0$. But, I see in textbooks that $p_e=p_a$ corresponds to ...
4
votes
0answers
174 views

What is the minimum melting point a material need to have in order for it to be used for the rocket chamber and nozzle?

I know the rocket temperature can go up to 3500 degree Celsius especially at the combustion chamber where it is the hottest. However I know there are cooling measures to cool the surface of the ...
4
votes
0answers
932 views

How is the process of launching a rocket mathematically modeled up front?

What I am looking for is an example where real persons in the real world really need to mathematically model a situation before they need to calculate the average and instantaneous rate of change. I ...
3
votes
0answers
52 views

Why are hexa airfoils used on rockets despite having more drag that diamond airfoils?

I was doing a study on airfoils shape for a rocket. I tested the diamond and the hexagonal airfoil with Missile DatCom, RasAero and the Shock Expansion theory and from my results it seems like the ...
3
votes
0answers
76 views

Falcon 9 Landing Speed

I wanted to know what the fastest speed is that a Falcon 9 can land at and thus the max force the landing legs can withstand. I assumed the mass when landed is 26,000 kg (I once heard that somewhere). ...
3
votes
0answers
75 views

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 ...
3
votes
0answers
80 views

Maturity of interplanetary rockets technology with known fuel supply is close?

Considerably, the scale of current jet propulsion rocket technology to leave Earth is closely connected to the target delivery mass, mission goal and the required fuel quantity to lift and deliver ...
3
votes
0answers
66 views

Reliability of self pressurization of propellant tanks for liquid engines

In a cryogenic propellant tank, the liquid always continuously changes into gas which pressurizes the tank. To pressurize the tank more we can run the liquid through the pipes along the outer wall and ...
3
votes
0answers
61 views

Pressurization line (Helium to LOX tank line) chilling while pressurizing LOX tank

I have read that in rockets and launch vehicles Helium is used for the pressurization of propellant tanks. What temperature Helium is stored at? If Helium is stored at room temperature then while ...
3
votes
0answers
198 views

What is meant by chamber pressure in rocket engines?

Is "chamber pressure" the pressure at the tip of the injector, or the pressure before combustion inside the chamber, or the pressure after combustion inside the chamber?
3
votes
0answers
113 views

Do rocket labs store propellants at higher pressure than the other rockets?

It is known that the Rutherford engines run on an electric pump-fed cycle. There must be a trade-off between the tank pressure of the electron rocket and battery capacity, for batteries are dead ...
3
votes
0answers
41 views

Why GSLV uses different stage seperation mechanism for their different varients

Why GSLV mk II is using Marman mechanism for stage separation but GSLV mk III is using Collet mechanism for stage separation?
3
votes
0answers
73 views

How is supersonic rocket exhaust able to match sea-level pressures?

I understand that the diverging portion of a rocket nozzle speeds up the flow and also expands it, in order to best match ambient pressure outside. However, doesn't higher speed flow lower the ...
2
votes
0answers
27 views

What is the minimal distance of clearance in the direction of flight path for a rocket?

Usually the rocket launch sites are placed on a coast or a place where there's basically no civilian buildings in the direction of flight path. Is there a standard/regulation on the minimal ...
2
votes
0answers
21 views

How to create a new reactant Ammonium Dinitramide NH4[N(NO2)] in NASA CEA?

Ammonium Dinitramide(ADN) is a compound used as a green propellant for spacecraft propulsion applications. ADN-blends like LMP103S and FLP-106 are currently under development. However, performing a ...
2
votes
0answers
80 views

Could a fat rocket be used on Mars?

Since Mars' atmosphere is around 2% the density of Earth's then could a much wider rocket achieve orbit? Could the rocket be in the shape of a capsule or an optimal shape for reentry on Earth?
2
votes
0answers
60 views

Payload fairing separation- Event based or time based?

Refer the answer for this question How strong and "hot" is the wind on the payload after the fairing is deployed at ~110km? It is clear that the fairings are separated when the free ...
2
votes
0answers
36 views

Conditions and sensors that can be used for parachute deployment?

I'm looking for an explanation on ideal conditions/considered factors when a parachute is deployed (particularly in large competition rockets). Also what sensors should be used to measure these ...
2
votes
0answers
49 views

Trying To Understand This Characteristic Velocity To Force Problem

Having problems trying to solve part b of this problem. Rocket Propulsion Elements 8th - Chapter 2 A jet of fluid hits a stationary flat plate in the manner shown below. (a) If there is 50 kg of ...
2
votes
0answers
37 views

Effect of the location of igniter in starting liquid rocket engine

What will be the effect of off axis igniter, say a Spark igniter has to be used along with a pintle? Will the igniter being off axis have any effect on engine start? Also, will an off-center igniter ...
2
votes
0answers
57 views

How to make a orbital launch tube work?

Normal rockets would not work in a pressurized tube, but could a stage be made for the diagonal launch tube to save fuel and weight? Can the bottom stage be nuclear powered? Unlike the piston launch ...
2
votes
0answers
56 views

Is it feasible to take liquid Helium in a Pressure Fed System?

Can liquid Helium be flowed through a heat exhanger to increase its temperature and pressure which will further pressurize fuel-oxidizer tanks.
2
votes
0answers
148 views

Exhaust plume length variation across different rocket types

In rockets we see exhaust plume smaller and bigger. I know length has some relation with the fuel mixture ratio (not confident about it). How to calculate, or at least understand, the variation in ...
2
votes
0answers
96 views

Which solid fuel is optimal for light rocket?

I am in search of comparatively cheap and powerful enough solid fuel. I've found rocket candy, but is it enough to reach 1km altitude? (My aim is a 2 metre high rocket with 0.5kg of payload.)
2
votes
0answers
54 views

Building a Drag model for rocket optimization

I need to build a drag model for my rocket optimization program and I stumbled upon by the following formula: $CD = CD_c(M)$, $K_n < K_{nc}$, $CD = CD_{fm}$, $K_n > K_{nf}$, $CD = CD_c +(CD_{...
2
votes
0answers
67 views

How can the delta-V be calculated depending on the launch altitude above sea level?

If we assume that we have a given launcher that is able to produce a $\Delta v$ of 10km/s at sea level takeoff, and is able to reach an LEO of 200km above sea level, what LEO altitude would that ...
2
votes
0answers
162 views

Are there any complications of the position of the oxidizer injector on Orbitec's vortex rocket engine?

Orbitec's vortex rocket engine injects oxidizer from near the nozzle up the wall of the engine chamber in a vortex. The oxidizer injector being in this position seems unusual. Are there any ...
2
votes
0answers
85 views

ULA/Ball Aerospace Intern Sport Rocket

So I've seen ULA post about their intern rocket launch a couple of weekends ago and was curious: What are the performance specs on the motors used for the first/second stage? (Class, quantity, etc.) ...
2
votes
0answers
153 views

Given a constant thrust to weight ratio, how to calculate the quickest path between two points on earth?

I'm trying to understand what would shortest paths could looks like. Let's assume a few things We have a constant thrust to weight ratio We do not need to decelerate We need to take drag into ...
2
votes
0answers
143 views

What are the maintenance benefits of SABRE engine technology for SSTO launchers?

What are the maintenance benefits of the SABRE engine over all the other engines being considered for the propulsion concepts for SSTO Reusable launchers?