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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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35 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
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1answer
101 views

How high could a weather balloon be used on Mars without rupturing?

How high could a weather balloon be used on Mars without rupturing? Assume that the balloon is adapted for Mars' atmosphere and gravity from standard high altitude balloons used on Earth.
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51 views

Reducing the aerodynamic drag of multi-engined rockets: aft wake area

Have there ever been thoughts of reducing the aerodynamic drag that results from the empty space between rocket engines? More precisely, this extremely low-pressure area sucks up ambient air and ...
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0answers
32 views

Analyzing Amateur Rocket Stability and Range Safety

I am working with a university bunch of other university students on building a very large amateur rocket. Our objective with this rocket is just to go very high, with no significant payload or ...
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0answers
24 views

Air flow over an airfoil [closed]

We know that in real viscous flow, boundary layer exists around the airfoil and there will be a separation point which flow starts to separate from the back of the airfoil( velocity gradient equal ...
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1answer
1k views

Soyuz Steering during Re-Entry

In this youtube video, it talks about steering Soyuz by changing lift. Why does roll rotation help in changing lift and also helping in cross range steering? I am looking for an answer from ...
6
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1answer
293 views

The aerodynamic stability of the truncated cone shape

Can someone explicate the stability of the truncated cone shape of the reentry vehicle of a spaceship when moving in the atmosphere with its bottom facing forward? It seems counterintuitive that it ...
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1answer
291 views
+50

Is a ballistic blimp entry possible on this way?

Could the entry of Mars with balloons work by inflating to equalize with the atmospheric air pressure, while establishing buoyancy before meeting the ground? Would a balloon pop if dropped from space?...
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2answers
86 views

Could the $C_L$ of the X-15 be calculated from the flight data near the Kármán line altitude?

The "lift coefficient" $C_L$ can be very different for one specific aircraft at different speeds. According to this article from NASA about the lift coefficient: So it is completely incorrect to ...
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1answer
99 views

Does an airplane in orbit near the Kármán line altitude, with the air providing lift, ever reach orbital velocity? [duplicate]

The equation for an airplane in orbit with the air providing lift would be: $$\frac{GM_Em}{(R+h)^2} - \frac{\rho(h) v^2 S C_L}{2} = \frac{mv^2}{R+h} $$ $GM_E$ is Earth's standard gravitational ...
8
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1answer
1k views

What is the most aerodynamic Satellite?

From what I understand at least in the lower orbits you want the least amount of drag possible. My brain is telling me that a long pole or submarine shape satellite orientated to the direction of ...
3
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5answers
1k views

Could rockets launched from the ground use wings in the stages?

Could a slower or smaller rocket take advantage of lift if all the stages had wings? Could the stages reduce splashdown impact forces by using a spinning seedpod-like design (as shown in the image ...
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3answers
217 views

Is the equation showed below the right one for an airplane flying at the Kármán line altitude?

$$\frac{GM_Em}{(R + h)^2} - \frac{ \rho v^2 S C_L}{2} = \frac{mv^2}{R + h}$$ $GM_E$ is Earth's standard gravitational parameter , $R$ is Earth's radius and $h$ the altitude of the airplane above the ...
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1answer
148 views

Does a credible Kármán plane reach escape velocity within 1 minute or does it follow the curvature of the Earth? [duplicate]

Edit: This question is no duplicate because here the dropping of the atmospheric density together with the horizontal line, play an important role. Furthermore none of the answers and question ...
0
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1answer
104 views

Is a Kármán Rocket Possible? [duplicate]

Why are the rockets not razor sharp, skinnier and taper off at both ends farther to cut through air better? Would making a rocket more aerodynamic allow it to be more efficient flying as a "Kármán ...
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1answer
142 views

Where does the definition of the Kármán line on Wikipedia come from?

According to Wikipedia's article about the Kármán line: The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity ( ...
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2answers
96 views

Is it correct to use the vis-viva equation when there are two forces acting on the orbiting body? [closed]

Edit: Although this question seems similar to the question "Is it correct to apply the vis-viva equation to an airplane that flies in a straight line", it is different because there the airplane flies ...
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1answer
103 views

Is it correct to apply the vis-viva equation to an airplane that flies in a straight line at the Kármán line?

The vis-viva equation models the motion of an orbiting body and it applies when the only force acting on the body is it's own weight. So is it correct to apply this equation to an airplane that ...
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0answers
61 views

Are there any advantages to being a smaller spacecraft for reentry?

Could a ship drop its cargo or shed weight before reentry to lessen the strain on the ship during reentry? Would a ship breaking down to smaller parts before reentry have any advantages over being one ...
6
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0answers
73 views

Understanding Coefficient of Drag Verses Mach Number for Launch Vehicles

I've been working on a design for a sounding rocket that can go to the Karman line, that I want to make my senior capstone project next year. As a part of this process, I am making a program to ...
4
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1answer
123 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-...
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2answers
150 views

How do the dynamic pressure evolves during reentry?

During launcher ascent, dynamic pressure evolution is describe in this answer for the Saturn V. I suppose this is comparable from one launcher to another. Given the protections designed for reentry, ...
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2answers
241 views

Can it be calculated that near the Kármán line the lifting force equals the centrifugal force?

According to Wikipedia about the Kármán line: In the final chapter of his autobiography Kármán adresses the issue of the edge of outer space: ...or 24 miles up. At this altitude and speed, ...
6
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2answers
212 views

Drawbacks and advantages of two slidable & rotatable control surfaces for BFS sized spaceships

BFS (SpaceX's Big Falcon Spaceship) is in development and has seen between 2016 and 2018 three major design modifications. January 2018 I asked here how BFS planned to manoever during aerobraking. ...
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2answers
484 views

Is the definition of the Kármán line from Wikipedia right? [closed]

Edit: this question is about making clear that the Wikipedia's article about the Kármán line is an interpretation, not the definition ! Why not consider the Kármán line as a curved boundary that ...
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2answers
305 views

Why does in-flight mission abort often ends in ballistic high-g reentry?

I am seeing a lot of references to the “ballistic reentry” mode of the crew return vehicle in relation to the abort during the powered ascent stage. In partiulat, the recent crewed Soyuz MS-10 abort ...
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0answers
89 views

Did the Shuttle have a drag penalty for ascent with a negative angle of attack (AOA)?

@OrganicMarble's answer mentions Because the Orbiter wings developed lift at zero angle of attack, the high dynamic pressure portion of ascent had to be flown at a negative angle of attack, close ...
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8answers
5k views

How would a long pole be transported to space?

Can a long pole or a set of poles be strapped to the out side of a rocket (like a bottle rocket)or on the nose as an external payload without interfering with the aerodynamics of the rocket? How would ...
2
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1answer
316 views

What is the terminal velocity on Mars?

How would I calculate the terminal velocity of Mars? What is the terminal velocity of a balloon entering Mars' atmosphere? Would a balloon pop if dropped from space?
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4answers
2k views

What causes a rocket to be destroyed during launch other than leaking fuel?

There were some famous accidents where rockets launched and just went up into flames. Many had something to do with leaking fuel in some sort. I want to focus on aerodynamic stress however, like when ...
2
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0answers
50 views

Aerobraking on Mars

I am looking for a calculator or formulas that can be used to calculate the aerobraking on Mars mission. I have found some data on previous Mars flights where aerobraking was used and all my current ...
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2answers
297 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 (...
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0answers
65 views

Falcon fairing half - between separation and parachutes deployment

How does Falcon fairing half behaves in atmosphere before parachutes deployment? What is its free fall attitude in atmosphere? Is the fairing's attitude stable (with some wobbling, but without ...
9
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3answers
1k 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 ...
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1answer
443 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 ...
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1answer
357 views

Could Space Shuttle's wings be diminished?

From Wikipedia The crucial factor in the size and shape of the Shuttle orbiter was the requirement that it be able to accommodate the largest planned commercial and military satellites, and have ...
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3answers
377 views

What are these circular structures around the rocket?

Youtube video of the Iridium-6/GRACE-FO NASA Launch (Falcon 9 SES-12). Edit 31 May: Too bad they have changed the content of the video (and still call it 'live'), so that you can no longer see the ...
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1answer
256 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 @RusselBorogrove's question, Cause of apparent plume deflection on SES-10?" and the Block 5 launch Bangabandhu Satellite-1 Mission at ...
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1answer
5k views

Why is Falcon 9's fairing so big?

The Falcon 9 fairing costs millions of dollars. It is 5.2 meters wide while the rocket itself is only 3.7 meters wide. There is no aerodynamic reason that the fairing has to be so big, since Dragon ...
3
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3answers
733 views

Would a balloon pop if dropped from space?

Could a "simple" inflated party balloon be dropped from space entering an atmosphere? The first case at orbital speed, the second case just outside the atmosphere and the third interplanetary? The ...
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4answers
6k views

Why are the bottom of most stages flat?

When looking for rocket engine images, I noticed that the bottom of the stages are almost flat. That does not seem aerodynamic. I understand this is not a primary concern for upper stages (mainly ...
9
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2answers
3k views

Why not jettison the nose-cone from Falcon Heavy side boosters for better control authority?

With February 6th's launch of Falcon Heavy we saw the landing of both side boosters. During the past few weeks and again in the press conference today I've heard over and over about the increased ...
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0answers
45 views

Atmospheric Entry Vehicle: Wind frame representation and Visualization

I am looking at entry dynamics for a convex blunt aeroshell. We use Heading angle, bank angle and flight path angle for description of attitude from local horizon axes system. While it is sufficiently ...
5
votes
1answer
245 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 ...
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0answers
102 views

What aerothermal effects present significant challenges in supersonic retropropulsion?

One of NASA's plans for future mars entry, descent and landing missions includes an ambitious deceleration process involving retropropulsion in a supersonic airflow environment. I know that previous ...
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2answers
872 views

How great is the stress on a rocket at max-q [closed]

How much more stress does a rocket experience during max-q compared to other parts of the flight (such as when it is at rest on the pad)? Use data for any 'cylindrical' rocket if a specific example ...
6
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1answer
538 views

Why are the cells on grid fins square in shape?

What is the reason for the square shape of the cells on grid fins such as those on the Falcon 9 landed by SpaceX, on missiles, or other places?
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2answers
1k views

What happens if the Falcon 9 launches with its grid fins open?

Let's suppose that the grid fins of the Falcon 9 remain open and the rocket still launches. This is probably never going to happen because the SpaceX team is exceptionally good, but I am trying to see ...
7
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1answer
367 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 ...
9
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1answer
705 views

Just how much can tall skinny rockets bend? (roughly, safely)

Below is a GIF I prepared and used in an earlier question, and the answer seems quite reasonable. With a height to diameter ratio of about 70 m to 3.7 m (nearly 20:1) a weight-conscious design, ...