Questions tagged [aerodynamics]

the effect on a spacecraft of moving through atmosphere, how its density, pressure, temperature, flow velocity, and viscosity affect a craft, and how lift and drag can be used to modify that.

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11 votes
1 answer
328 views

How well would a supersonic aircraft perform in the Martian atmosphere?

I started getting curious about this question during my Flight Test Engineering class. My professor was talking about a part of the International Standard Atmosphere that is a similar pressure to that ...
2 votes
2 answers
137 views

References on Launch Trajectories

Are there any good texts/papers about computing trajectories from launch to LEO? Specifically discussing atmospheric effects, gravity turns, launch sties, etc. and numerical simulation. I've seen a ...
6 votes
2 answers
770 views

Aerodynamically - can a rocket be over 30 meters in diameter?

The past and current designs of rocket launchers have diameters up to 8-10 meters (Saturn-5, N-1, SLS, BFR), up to 13-14 meters for max cross-section dimension for Space Shuttle and Energia-Buran (...
17 votes
1 answer
2k views

How high could Ingenuity fly?

On its 59th flight, Ingenuity achieved a height of 20 meters - twice as high as its maximum height during the original 5 flights that it was designed and expected to last for. In the scheduled 61st ...
4 votes
1 answer
270 views

What is the significance of a heat flux value of 1135 W/m^2 when jettisoning the payload fairing? [duplicate]

I have seen that many rockets jettison their payload fairing at an altitude where the aerothermal heatflux is leass than or equal to 1135 W/m^2. What is the reason behind considering this particular ...
0 votes
0 answers
48 views

Hypersonic dynamic shift in large vs. small lifting bodies

Background: Lifting bodies have been tested at small scales, though not during re-entry. For instance: the NASA HL10 Such Lifting-Body designs are seemingly here to stay with craft such as Dreamchaser ...
0 votes
0 answers
90 views

How do you approximately calculate the center of pressure during flight? [duplicate]

I'm working on a simulator for landing the falcon 9 booster rocket. I'm aiming to incorporate aspects like the effects of restorative torque. However, I've been trying to figure out how to determine ...
0 votes
0 answers
120 views

How to Model the Aerodynamics of Landing a Falcon 9

I'm currently working on a landing simulation for the Falcon 9. One of my primary tasks is to model both the environment and the rocket. In a previous rough simulation, aerodynamics were mostly ...
0 votes
0 answers
48 views

When solving flight dynamics equations, should the integration variables be set in one or multiple reference frames?

when establishing the differential equations of flight dynamics, I have 2 choices: 1、establish the equations in one coordinate system (e.g. in the earth centered inertial system), then doing the ...
10 votes
2 answers
845 views

Would a dimpled heat shield reduce heat transfer during reentry?

Would a large ceramic golfball absorb less heat on reentry than a standard sphere? From aerospaceweb.org: The difference in the flowfields around a smooth sphere and a rough, or dimpled, sphere ...
4 votes
1 answer
136 views

Would it make sense to compress air around a bell nozzle during booster ascent?

Regarding boosters having one single liquid fuel engine, such as Delta 4 for example. Would some sort of annular aerodynamic device, attached to the skirt and placed around the bell nozzle, help ...
12 votes
3 answers
3k views

What would a "Kármán plane" look like, a bird, or a plane?

If I understand correctly (which I might not), the Kármán line is roughly the altitude where a "Kármán plane's" upward lift force at the orbital velocity for that altitude would be equal in magnitude ...
-6 votes
2 answers
445 views

What's the *calculation* for the altitude near the Kármán line where the lifting force equals the centrifugal force? [duplicate]

Edit: This question is not a duplicate of the associated question and has no answers to it that were posted for that associated question. This question asks specifically for a calculation, the ...
7 votes
3 answers
353 views

Do larger less dense objects heat less while entering the atmophere?

When a space craft enters the atmosphere, it gets hot and heat shielding is needed. Do objects with more surface area and less density heat up less then heavier, smaller objects? Could an object with ...
4 votes
1 answer
223 views

Does a capsule rotate naturally during atmospheric re-entry?

If during atmospheric re-entry a capsule (with a shifted center of mass to produce lift) does not produce any rcs thrust, will the capsule naturally roll? and why?
7 votes
1 answer
634 views

Upper stage structural loads on ascent?

In another question, this came up: For example, if a Falcon 9 launches 20 tons of fuel to dock in LEO, how can the same upper stage be used to launch 40 tons of fuel to the same orbit? Doesn't it ...
17 votes
4 answers
6k views

Is this egg-shaped nose cone a good, aerodynamic design?

So Jeff Bezos has recently travelled to space aboard an Amazon-funded rocket, which has an unusual, egg-shaped nose. However, just about every other rocket I've seen has more of a cone-shaped nose, ...
4 votes
1 answer
401 views

Disadvantage of interstage trusses on Soyuz launch vehicle?

Brian Tompsett gave a detailed explanation of the advantages of the trussing in his answer to the question Why do the Russians use these fence-like interstage fairings? The gap between Stage II and ...
9 votes
1 answer
552 views

Why would a significant non-zero angle of attack be an advantage during 1st stage burn?

From videos of both the SES-10 launch shown in @RussellBorogove's question, Cause of apparent plume deflection on SES-10?" and the Block 5 launch Bangabandhu Satellite-1 Mission at ...
2 votes
2 answers
1k 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 ...
0 votes
1 answer
320 views

Why does igniting propellant provide more thrust?

My confusion stems from the relationship between thrust and the pressure distribution in the thrust chamber. For a given chamber pressure the wall static pressure along the nozzle is a function of ...
27 votes
5 answers
11k views

Could a helicopter fly on Mars?

Helicopter drones are awesome fun down here on Earth, but what if... we took one to Mars? This sounds like a good question for Randall Munroe. But I read about a proposal to send a helicopter drone (...
6 votes
1 answer
2k views

Could we achieve aerodynamic and aerostatic lift on the Moon if it had an atmosphere of xenon?

The Moon is not capable of keeping an Earth like atmosphere, nor is it practical to keep satellites in lunar orbit. Which means all transportation and communication would need to be ground based. No ...
9 votes
1 answer
239 views

How heavy were Perseverance's balance masses?

Perseverance ejected two 70 kg "cruise balance masses" just before it became an airplane, to move its center of mass off axis and increase its angle of attack from 0° to about 16° to make it ...
8 votes
3 answers
457 views

Might Ingenuity tip over?

While Ingenuity patiently waits for its preflight checks to pass, how likely is it that a wind gust could tip it over? How strong and how rare a gust? Those rotors have plenty of area. (Surely NASA ...
24 votes
2 answers
5k views

What are the pros and cons of Aerospike nosecones?

Some rockets, mainly (only?) ICBMs have Aerospike nosecones Why are they preferred in lieu of traditional nose cones? Illustrations: An aerospike nosecone on a trident ICBM Video including the ...
9 votes
2 answers
275 views

Why might Ingenuity be able to fly faster when it flies higher?

A 2022 March 15 NASA press release says: A recent software change already on the rotorcraft frees Ingenuity from its previously programmed maximum altitude of 50 feet (15 meters). The altitude gains ...
7 votes
2 answers
1k views

What was the actual Q-alpha limit for Saturn/Apollo launches, and what was the typical max Q-alpha?

Organic Marble's answer to a previous question about Apollo abort limits clarified that the figure of concern was the product of dynamic pressure (Q) and angle of attack (alpha), with the 100% level ...
11 votes
1 answer
408 views

Why making such a big deal with Max Q?

At each SpaceX launch, they always make some big deal of Max Q which most of the time comes at around 13Km and at a speed of 1700Km.h-1 But on the way back, stage 1 is at this same altitude of 13km at ...
4 votes
1 answer
252 views

Which deorbit trajectory minimizes reentry heating?

Atmospheric reentry, as I understand it, is a balancing act between minimizing delta-v needed and not burning up or breaking up in the atmosphere. The higher the velocity on reentry, the greater the ...
8 votes
2 answers
455 views

Would an autogyro be a good solution for a space re-entry vehicle?

From what I can imagine, using an autorotative maneuver as a re-entry control method would be a good idea because I believe very high lifts would be generated when relative air speed is high (first re-...
1 vote
0 answers
90 views

Do fins with slightly different masses but the same surface area affect the stability of a rocket?

Each of four fins of a rocket are of slightly different masses like( 0.204, 0.2, 0.199 and 0.19 kg). If they have the same surface area, will that severely affect the stability (spin) during flight? I ...
1 vote
1 answer
285 views

Lift and Drag of a Model Rocket

Talking about aerodynamic forces in a model rocket, I believe that Lift and Drag are the components of a net force which acts on the Center of pressure. Knowing this, could I affirm that the net ...
4 votes
3 answers
618 views

Merging Shuttle and External Tank to reduce reentry heating

The Space Shuttle needed a high-performance heat shield that caused much grief over it's operational life. Having a large surface area on a reentering vehicle reduces temperatures by causing the ...
9 votes
1 answer
707 views

How hot do the nose cones of fairings actually get on ascent?

I've been reading into aerodynamic heating of rockets, and it's seemingly a rather complicated topic. It's relatively easy to calculate the stagnation temperature at a given mach number, and that is ...
19 votes
3 answers
15k views

Can a reentry be done slowly?

The usual approach to reentry is fast and hot. There's a lot of energy to be lost, and doing it quickly has some advantages: You can dump energy into hypersonic air, and then leave that heat behind ...
6 votes
1 answer
244 views

Up to what Mach/Reynolds numbers will Ingenuity be tested?

From an aerodynamics perspective, velocity alone is insufficient to describe the flow regime experienced during flight. For the Ingenuity helicopter, what specific Mach numbers and Reynolds numbers ...
2 votes
1 answer
441 views

How do grid fins actually work? Which aerodynamic mechanism(s) produce the torque on the spacecraft?

I’m trying to model the steering force that grid fins exert on a falcon 9. I know these things are not just grid-shaped fins but actually grids of fins. And each of those fins will experience drag and ...
2 votes
1 answer
355 views

Why the max dynamic pressure might not happen at maximum drag instant?

I understand that is that when a rocket accelerates the drag force grows dramatically since the force is related to velocity squared. But, at the same time, the density is decreasing, so the force is ...
3 votes
1 answer
7k views

What's the atmospheric drag coefficient of a Falcon 9 at launch (sub-sonic, large fairing)

While I said just a few hours ago that "There's almost no such thing as a dumb question! this one just might sound like one. I'm making some slides about first principles thinking applied to ...
5 votes
2 answers
213 views

Using lasers to reach the Karman line

I've just seen this Anton Petrov video: New Type of Laser Levitation Could Help Us Explore the Mesosphere. It's about this new form of levitation that uses lasers to heat up the air underneath a craft,...
-4 votes
1 answer
281 views

Using side thrusters on a missile to create an angular acceleration

Assume a rocket is standing on the ground with mass = 1000 kg, and near the top of rocket we apply a force of 100 N for say 1 sec, now assume that this is sufficient to tip the rocket over/start ...
4 votes
0 answers
136 views

During space shuttle reentry, why was the sign of GALR based on mach number rather than directly on alpha?

(My apologies if this should go in Aviation.SE instead - I'm not quite certain where questions regarding the behaviour of the shuttle's flight controls during reentry should go.) For flight in ...
2 votes
0 answers
93 views

Why are fins located on stage 2 of Iranian rocket Zol Janah?

Iranian launch vehicle Zol-Janah has fin like structure on the second stage of the vehicle. Does aerodynamic characteristics of vehicle improve with fins near the centre of mass? Also will the fins ...
26 votes
5 answers
2k views

Gliding into the atmosphere

The recent question about Cessna reentering from ISS got the answers that all imply a rapid drop. But from what I know, air drag is proportional: to square of airspeed to air density to attack ...
1 vote
1 answer
258 views

What is Direct Simulation Monte Carlo and why is it a good method for simulating spacecraft drag in VLEO?

Reducing spacecraft drag in Very Low Earth Orbit through shape optimisation J. A. Walsh and L. Berthoud (2017) show simulations calculating drag coefficients for different "nose cone" shapes ...
3 votes
0 answers
76 views

How large can heatshield holes be?

The tiles on the underside of the STS Orbiter had gaps between them to allow for the frame underneath to shift slightly. However, if the gaps were too large fillers were used. What controls the ...
3 votes
1 answer
235 views

How did the Space Shuttle prevent flying up when reentering the atmosphere?

Always when reentering the atmosphere, the shuttle was pitched up, right? When gliding through the mesosphere, how was it that it didn't fly up again then? Was it due to a certain distribution of ...
1 vote
3 answers
527 views

How to make a model rocket that doesn't spin?

I'm attempting to build a rocket with 8 fins (four on bottom and four smaller ones towards the top). The four fins near to the top will be attached to servo motors and programmed to stabilize or guide ...
2 votes
2 answers
338 views

Can the Space Shuttle land on Mars assuming there is a paved surface for landing?

Can the Space Shuttle land on Mars if it had a paved runway? Can the Space Shuttle use aerobraking and will its control surfaces provide attitude control? Can the parachute and braking systems stop ...