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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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 ...
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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 ...
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8 votes
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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 ...
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What performance can be expected from chemical rockets under Venusian atmospheric conditions?

Is it feasible to use either solid or bipropellant liquid rocket engines to lift off from the surface of Venus? "Reference datum" air pressure on Venus is around 9.3 MPa; even on the top of, say, ...
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7 votes
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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.
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7 votes
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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 ...
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6 votes
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What are the various ways that rockets measure the instantaneous thrust of each engine?

@DavidHammen's answer to Engine failure: how to detect? mentions thruster sensors. This intrigued me and so I thought I'd ask about how this is done. Thrust is a critical parameter to know in real ...
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6 votes
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SpaceX Dragon Shape: Power Series, Ellipsoid, or Haack/Von Karman?

The SpaceX Dragon module has a round apex typical of power series, ellipsoid, and Haack/Von Karman shapes. I'm wondering which of these SpaceX actually used. References would be appreciated. My guess ...
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6 votes
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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 ...
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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 "...
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6 votes
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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 ...
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6 votes
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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 ...
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6 votes
1 answer
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How does the flight trajectory of a GEO vs LEO mission vary for a Falcon 9 first stage?

How does the trajectory vary between the two types of missions? Specifically, how does the speed and velocity vary for the booster for a Falcon 9 mission?
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5 votes
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What is the benefit of an inverted rocket stage?

For example the Chinese rocket Jielong 1 has an inverted 4th (final) stage. So the payload sits between 3rd and 4th stage. When 3rd stage separates it has to do a 180 degree turn before igniting the ...
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5 votes
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Trussed strongback or hollow shell strongback?

I noticed that rocket Lab has a hollow rectangular section strongback made of steel, while few strongbacks like that of Astra [similar size] has a trussed structure for a strongback. is there any ...
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5 votes
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Have any stages of rocket killed aquatic animals?

This question may seem off-topic but I am curious.Those rockets that aren't reusable let their stages fall and splash down on the ocean. Is there any news reported that they have killed some aquatic ...
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Low-pressure pump-fed rocket engine?

I saw the above suggested in LEO on the Cheap. In P.130 it says: A compromise between high-performance/lightweight pump-fed vehicle designs and cost-optimized pressure-fed vehicles with heavier ...
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Why does kerosene need inducer?

We see inducers before the main kerosene turbopump in engines such as F1 and RD180. Given the property of kerosene having extremely low vapor pressure (~0.007 bar around room temperature), is this ...
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5 votes
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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 ...
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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 ...
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5 votes
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340 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 ...
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4 votes
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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 ...
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4 votes
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What is the highest RPM achieved through a spin-stabilized rocket/spacecraft?

The title explains it all. I know that the Star 48 kick motor rotated at 60 rpm through its burn. I'd like to know the fastest a rocket/stage has spun during a launch, as well as the highest ...
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4 votes
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How to estimate total CO2 emission per year due to rocket manufacture?

I'm working on a study on greenhouse gas emissions related to rockets. While I have the post-launch (atmospheric) emissions, I need data for emissions related to production. For example, according to ...
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4 votes
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176 views

How many turbine blades, engine seals and bearings do reusable rocket engines have and how are they inspected?

From previous year statements of SpaceX representatives, the most difficult and longest part of used F9 booster refurbishment are inspections of the most volatile parts of the booster's nine Merlin ...
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4 votes
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160 views

Most open source spaceflight missions revealed unintentionally

As of 2021 there are few fully open source satellites (OSSI-1, UPSat, FossaSat-1, Oresat, some more?) and numerous student groups building and documenting rockets. These projects are intended to be ...
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4 votes
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What are the implications of North Korean black and white patterns on missiles?

Black and white patterns on rockets were originally intended as roll patterns. They helped as a visual back-up for acceleration sensors measuring the roll, as discussed in this previous question What ...
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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 ...
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4 votes
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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 ...
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4 votes
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277 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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4 votes
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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 ...
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4 votes
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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). ...
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4 votes
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55 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?
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4 votes
0 answers
82 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 - $3000 K$ ...
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4 votes
0 answers
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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 ...
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4 votes
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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 ...
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4 votes
0 answers
237 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 ...
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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 ...
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4 votes
0 answers
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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 ...
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4 votes
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670 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: ...
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4 votes
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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 ...
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4 votes
1 answer
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How to experimentally determine the degree of atomization of the propellants mixing in a fuel injector?

When validating a fuel injector design on a test stand using liquid water to simulate a liquid-liquid fuel injector(the one i'm working with currently is a pintle design but I suppose one could ...
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3 votes
0 answers
96 views

How to find the altitude of a rocket?

I know this may be a very simple question, but is there any formula from which I can estimate the altitude of a liquid fuel (model) rocket based on the propellant, oxidizer, mass, density, etc? I've ...
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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 ...
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3 votes
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Rocket equation with Drag factor

For the avg Thrust of 2 kN, burn time = 3.5 s, burn rate= 1.4, over the time diff of dt = 0.1 sec Isp = 140 sec Cd for the Ogive nose cone C-section = 0.75 Cross-sec Area of the ogive nose cone = 0....
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3 votes
0 answers
128 views

SpaceX estimates for Starship and Super-heavy heat shields maximum heating during their orbital and suborbital reentry

Did SpaceX made public their estimates for Starship orbital vehicle heat shield maximum heating (and overall reentry heating profile) during orbital reentry on Earth and same for Super-heavy booster ...
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3 votes
0 answers
158 views

What is the inlet and outlet pressure of Merlin LOX/RP-1 turbopump?

I got the inlet and outlet pressure of Saturn V engines turbopumps here, but I couldn't find the turbopump pressure of the Merlin engine of Falcon 9.
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3 votes
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92 views

Is steam a good gas to use for a small RCS thruster on a small rocket?

Is steam a reasonable tradeoff from other hot/cryogenic gases in order to have safety and have it easily obtainable? Thanks
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Rocket Engine - Actuator in Loop Simulations

For Actuator-In-Loop simulations, why are the rocket engine nozzles along with the thrust vector control assembly (including the actuators) kept inverted on a platform like in the attached image or as ...
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3 votes
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Can we re-fuel solid-core nuclear thermal rockets?

Most solid-core nuclear rocket designs seem to have a rather short fuel lifetime (and one that wastes most of the uranium or plutonium) due to the buildup of fission products (combined with the very ...
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