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Questions tagged [atmospheric-drag]

Questions regarding atmospheric drag which includes the resistance offerd by a moving object in fluid

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9 votes
2 answers
4k views

Can Maglev trains ever reach escape velocity?

NASA is planing to build a levitating train system on the Moon. For Moon, would it be possible to build a large scale system equivalent to maglev trains, to accelerate (for example) a mining cart of ...
8 votes
1 answer
1k views

At what altitude do the effects of atmospheric drag completely disappear?

The spate of K-questions got me thinking: At what point does atmospheric drag disappear1 with the pressure from sunlight, solar wind, or other forces becoming overwhelmingly dominant? I'm guessing it'...
8 votes
3 answers
1k views

Why does Earth's atmospheric density have a big "knee" around 100 km? Is there a good analytical approximation?

I've used a quick very rough approximation of the drop of atmospheric density with altitude in this answer and in this answer by using a single exponential and scale height parameter, but that's not ...
6 votes
0 answers
87 views

What is the lowest viable circular orbit around Mars that can last at least one week?

Supposing you wanted to launch a spaceship from the surface of Mars into orbit around Mars. It would stay in orbit for up to one week while you prepared a second rocket that would dock with it to ...
6 votes
0 answers
1k views

Why is the diameter of the boosters of some launch vehicles smaller than the diameter of their payload fairing?

Whilst watching yesterday's Starliner launch I've noticed how skinny that Centaur (3.1m) looks compared to the CST-100 (4.5m). Looking up the Atlas V I was amazed to find out that it has even larger (...
16 votes
5 answers
9k views

Where can I find data for Atmospheric density vs. altitude?

I'm looking for information on atmospheric density in Earth orbit. All the atmospheric density tables and graphs I've found go no higher than 100 km. Definitions like the US Standard Atmosphere don't ...
8 votes
3 answers
3k views

What is the density of the earth's atmosphere at an altitude of four hundred kilometers?

What is the density of the earth's atmosphere at an altitude of four hundred kilometers? I want to use it to calculate the drag on something in orbit near the ISS. The Jacchia Reference Atmosphere is ...
2 votes
0 answers
67 views

Has propulsion utilizing solar sail / drag effects of solar panels achieved orbital rendezvous? If yes, is there any utility for clearing space junk?

It has been proposed to use solar panels as solar sails and drag control by alternately feathering panels during different phases of orbit. It is claimed this can alter light pressure and drag enough ...
6 votes
5 answers
3k views

Earth re-entry from orbit by a sequence of upper-atmosphere dips to reduce kinetic energy?

There are quite a few questions on this sort of theme here, and I've also read one or two other things, like non-ballistic re-entry. So this might be a duplicate, but I don't think so. To clarify: I'm ...
1 vote
0 answers
99 views

How to set a constant density model in STK'S Astrogator

I'm trying to verify a simplifying orbit maintenance strategy obtained from one of my numerical tools using Astrogator as a propagator. My tool uses a constant density value obtained by averaging the ...
3 votes
3 answers
1k views

Would it be possible to avoid the heat-from-friction problem when re-entering the atmosphere by performing (vertical) "U-turns"?

If you lift a swing at a children's playground and release it will swing back and forth for a while, losing some altitude in each swing, mostly (?) due to drag. Eventually it has lost all energy and ...
3 votes
1 answer
67 views

Any place to download ATMOP's DTM-2012 / DTM-2013 models?

Once there were an old "Drag Temperature Models" DTM2012 and DTM2013 at http://www.atmop.eu According to web archive in 2020 they were still available for downloading after registration: ...
10 votes
2 answers
5k views

What causes a satellite's orbit to decay?

Why do orbits of satellites orbiting at sufficient speed, far beyond the Earth's atmosphere, decay if there is no atmospheric drag? What drag is applied on the satellites at that altitude?
3 votes
1 answer
206 views

What is the reason Starlink satellites took 4 days to re-enter during the accident on February 2022?

I am reviewing the incident that knocked out 39 Starlink satellites earlier this year. As I explain in this thread, there was a modest magnetic storm on the 3rd of February, which increased ...
4 votes
1 answer
252 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?
1 vote
0 answers
168 views

How to compute orbital decay of a cubesat?

I'd like to compute the orbital decay of a cubesat in LEO/VLEO due to atmospheric drag. Here is what I've done: Based on the Satellite Orbital Decay Calculations document coming from the Australian ...
7 votes
4 answers
3k views

Is aerodynamic lift ever useful in rocket flight?

When a rocket is traveling through an atmosphere, the component of the aerodynamic force in the direction of motion is called drag, and the component perpendicular to that is called lift. Usually a ...
19 votes
4 answers
12k views

Why do spacecraft enter the atmosphere violently instead of a smooth spiral?

Why do spaceships almost make a straight line in the atmosphere when coming back to earth? This makes the ship undergo high stress and temperature. Why don't they make a spiral trajectory so that they ...
19 votes
4 answers
10k views

Why are rockets cylindrical?

What are the drag coefficients for a cylinder, a wedge, etc? I know there are other reasons for a rocket to be cylindrical that aren't related to aerodynamics such as efficiency when mixing the ...
9 votes
3 answers
456 views

Would this Starship design alternative be viable?

Considering Starship's atmospheric entry, belly dive and "bellyflop", latest iteration displays four aerodynamic surfaces, two aft fins and two canard fins. Soon, this configuration will be ...
12 votes
1 answer
585 views

Could SpaceX's Starship's landing and restart process work on Titan?

Gravity on Saturn's moon Titan is much weaker and the atmosphere is far denser than either Earth's or Mars', which Starship seems to have been designed for. Could an unmanned Starship do an Earth-...
1 vote
0 answers
39 views

Is DTM2000 density model expecting adjusted or observed solar flux?

I know two models to calculate the atmosphere density during a satellite orbit propagation. The two models are NRLMSISE-00 and DTM-2000. To feed the models I'm using Space Weather Data provided by ...
1 vote
0 answers
48 views

How does "onboard GPS" suggest "escalation speed and severity of a storm caused atmospheric drag to increase up to 50 percent"?

Engadget's says: A recent batch of SpaceX’s Starlink internet-beaming cubesats met with tragedy on February 3rd when a 49-member cohort of the newly-launched satellites encountered a strong ...
5 votes
1 answer
191 views

Maximum speed based on atmospheric altitude given maximum temp?

I saw the question Could escape velocity be achieved in the atmosphere? and thought it probably could've been asked better. I'm sure there's an equation to calculate the average heat generated by an ...
3 votes
0 answers
147 views

ISS propagation becomes much more accurate with reduced drag. Any ideas why?

I have currently been testing my implementation of a numerical propagator with the ISS. Without going into much details, the propagator considers Earth gravity (with the GGM03S model including zonal, ...
3 votes
1 answer
269 views

Soyuz: Do you know the coefficient drag and lift to drag ratio are during reentry?

I've been learning Python as a hobby the last two years. I like spaceflight too. Therefore I wrote this code to simulate the reentry of a Soyuz. I'd appreciate some feedback: https://github.com/fra-...
23 votes
2 answers
4k views

Why not increase contact surface when reentering the atmosphere?

If a craft were to increase the surface area where contact is made with air during reentry, I imagine the heat quantity per area unit would decrease, making the use of (heavy) heat shields less of a ...
6 votes
2 answers
2k views

Exactly how "Ferrari-like" was GOCE? Was its drag coefficient as low as the car's?

This comment mentions: This relation between drag and mass is taken to a relative (for satellites) extreme in GOCE which I think needed to be close to Earth to accurately sense the changes in gravity,...
4 votes
1 answer
144 views

How is it provided for that the uppermost stage doesn't orbit with the capsule/satellite together?

After a spacecraft reaches orbit and jettisons its last stage, that stage would be in the same orbit too. What are methods to avoid this, or isn't it cared about? In case of the Space Shuttle, the ...
5 votes
1 answer
278 views

What factors would contribute to a spacecraft's ability to maintain a very low orbit (VLEO) or at least orbits with very low perigees?

I asked What does account for a high coffin corner of a plane? in Aviation SE. Now I wonder what factors would contribute to a spacecraft being able to maintain low circular orbits (e.g. within 200 km ...
3 votes
1 answer
986 views

Modeling SpaceX's lift and drag versus angle of attack and Mach number

I've been trying to find data in the literature that would provide analytical expressions for the relationship between the lift and drag of an object similar in shape and size to the Falcon 9 first-...
0 votes
1 answer
174 views

What is the difference between "body drag", "frictional drag" and "pressure drag" for astronaut or aerobot atmospheric locomotion in microgravity?

Complaints below my answer to Would a higher air pressure on the ISS or elsewhere make it easier to “swim” in microgravity? about my spherical-cow estimate of how fast an astronaut can accelerate by &...
2 votes
1 answer
562 views

Using astrogator in STK to separate 2 satellites using atmospheric drag

So I can do an initial separation using Astrogator by using different areas. What I need to do now is to define a distance and at that distance the area that the satellites are propagating changes. ...
2 votes
1 answer
109 views

Change in drag coefficient when Dragon flips over on launch escape?

Consider the Falcon 9. In emergencies, the launch escape system will fire to separate and propel the crew module away from the rocket. After the engine shuts down, the payload trunk will separate ...
37 votes
4 answers
16k views

Effect of atmospheric drag on rocket launches and benefits of high altitude launch sites

What is the approximate influence of atmospheric drag on the cost of rocket launches? Is it beneficial to have launch sites located at higher altitudes? Cape Canaveral is at sea level, but I've ...
4 votes
1 answer
298 views

How would Ingenuity handle Martian Storm and dust devils?

Martian storms are quite common and can sometimes encompass most of the planet. Though the density of the Martian air is low, the speeds are pretty high (some have observed 26 m/s). How would the ...
7 votes
2 answers
1k views

Shear forces between Shuttle, tank, and boosters - what pushes what?

This is the question that I should have asked here. The space shuttle and the two solid rocket boosters (SRBs) are mechanically attached to the giant tank. SRB's, shuttle, and tank all experience ...
2 votes
1 answer
537 views

How is PICA different from other heat shielding materials?

What are the differences and why did SpaceX prefer to use PICA?
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 ...
14 votes
2 answers
3k views

Re-entry Heat Shield Alternative

Why is it that Controlled Re-entry Vehicles (like the most recent Orion & Dragon) do not use a strong magnetic field during re-entry to "shield" the blunt shaped end from plasma ? Reasoning: ...
15 votes
2 answers
8k views

What is the ISS drag?

ISS constantly loses altitude to air drag and other forces (tidal, electromagnetic). While finding that rate in the sources isn't that hard, with orbital mechanics of altitude loss actually increasing ...
10 votes
2 answers
2k views

How hard does atmospheric drag push on the ISS? Is it more than one pound?

A comment under this question has me thinking; with it's huge main structure and giant solar panels the ISS presents a very large cross-section to Earth's rarified atmosphere at 400 km altitude. So ...
1 vote
1 answer
270 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 ...
4 votes
1 answer
1k views

What is the lowest altitude that an ion thruster can be used for station keeping?

What is the lowest altitude that an ion thruster can realistically be used for station keeping before its small amount of thrust is overcome by atmospheric drag? Please state your assumptions such as ...
3 votes
1 answer
182 views

How many solar system bodies have "knees" in their atmospheres?

Discussion lead to citing Why does Earth's atmospheric density have a big "knee" around 100 km? Is there a good analytical approximation? who's answer is "monatomic oxygen". ...
4 votes
1 answer
252 views

Did the Space Shuttle crew have to worry about the ionosphere? What relevant training or specific briefings did they receive?

Comments below this answer tell us that the Space Shuttle always remained in Earth's atmosphere. When it visited the Hubble Space Telescope or the ISS or Mir it was still in the thermosphere and ...
5 votes
3 answers
290 views

Changes in Orbital Parameters Due to Drag

Other than STK, are there any commercially software packages available to model changes in orbital parameters due to increases/decreases in satellite drag. I am trying to figure out if aerodynamic ...
1 vote
2 answers
148 views

Why will OGO-1 reenter from an elliptical orbit rather than circularize first?

According to all the sources cited in Why does OGO-1's trajectory and imminent reentry come from sky surveys and NEO tracking rather than normal satellite tracking? OGO-1 is in a highly ...
5 votes
3 answers
1k views

Why does a satellite with a higher mass fall slower?

I was doing simulations in GMAT and I could observe that if I increase the mass of the satellite, the satellite falls slower ... and if I reduce the mass of the satellite, then it falls faster (I only ...
5 votes
1 answer
218 views

How to fit, into a cubesat, 29 trackable high drag subsatellites with well-defined aerodynamic profiles

Johnathan McDowell's recent tweet says: The @AerospaceCorp Aerocube-10a cubesat carries 29 small passive high-drag subsatellites used to probe the density of the upper atmosphere. 3 have been ejected ...