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# Questions tagged [drag]

Drag is the aerodynamic force that acts opposite of the object's velocity relative to the fluid medium it is in.

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### Inflatable tank/balloon use for recovery

Hopefully this idea makes sense. Basically if you've seen the space-truck (ROOST), you'll get where I'm going with this. I'm wondering whether an inflatable tank/tank lining could be used to produce ...
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### How do the interferometers on the drag-free satellite LISA receive power without altering their geodesic trajectory?

LISA is a proposed space probe designed to measure gravitational waves. It aims to measure gravitational waves directly by using laser interferometry. It uses a drag-free satellite design to protect ...
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### 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?
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### How can I derive Starlink specs looking at the incident of February 2022?

I am trying to calculate and speculate the specifications of Starlink satellites (mainly related to propulsion) based on the accident on the 3rd of February 2022. There are multiple sources that ...
154 views

### How to estimate base drag of a rocket during powered flight

I cannot find an authoritative resource that describes how to estimate base drag for a missile or space launcher during powered flight. There are plenty of resources that describe how to estimate the ...
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1 vote
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### 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 ...
1 vote
148 views

### cross parachute - drag coefficient

I would like to know whether there is a mathematical formula which gives the drag coefficient of a parachute. I suppose that the drag coefficient is a constant depending only on the geometry of the ...
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### Shouldn't space junk fall back to Earth on its own? How long will take for a ~1 cm piece of junk in LEO to fall back to Earth on its own for example?

I'm a noob in this subject and know little about space exploration, but I wonder about this every time I read the news: Wouldn't drag make all space junk fall back to Earth after some time? I'm ...
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1 vote
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### 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 ...
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### Drag and lift coefficient tables/plots for Saturn V/Space Shuttle/Other

I'm looking for drag and lift coefficient data to plug into my launch simulation. I could assume constant coefficients, but I'd like to structure my model to accept lookup tables, so I'm looking for ...
430 views

### Dragon ballistic/drag coefficients?

I'm looking for some estimates of Dragon's ballistic or drag coefficients in its reentry (heat shield forward) configuration. Estimates for other spacecraft would be useful also as they would give me ...
682 views

### What technologies enable or at least help satellite operation in Very Low Earth Orbit (VLEO)?

This answer to How low is VLEO? (FCC's newest approval for SpaceX) suggests VLEO begins (or ends I guess) at 350 km. The two bad things I know about in VLEO are an enhanced rate of altitude loss due ...
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### Design of starship fins

How much can the falling speed of starship approximately be reduced by the bellyflop fall with fins? Are we talking about numbers around 5% or 50% here? Wouldn't it make sense to put holes where the ...
224 views

### Orbit lifetime of a Nano-Satellite in 350 Km Orbit

I was trying to write a very simple program to calculate orbit life time of a nano-satellite. I got the atmosphere density as function of altitude from this site. ...
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### Is there a mathematical formula to calculate drag force without empirical testing?

Typically people put the interested rocket prototype in a wind tunnel to find out the drag force and use the drag force equation to calculate the drag coefficient of the rocket model. I am wondering ...
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### Source of Gregorek's popular drag equation in ESTES TR-11?

In the early 1970s, Gerald Gregorek wrote a technical note on drag for ESTES (maker of model rockets and parts from what I gather). The note is still very popular in the model rocket community, and it ...
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### 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,...
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### Can Oberth bike? Is biking up and down a series of hills a good real-world analogy for understanding either the Oberth effect and/or gravity drag?

When faced with a series of ups and downs while riding a bicycle, I try to pedal like mad near the bottoms to gain as much speed as possible. I do this due to some vague, ill-formed notion that either ...
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### 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 ...
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### What fraction of Terminator Tape™'s drag comes from interaction with Earth's magnetic field as a function of altitude? Is it ever important?

This answer states that Terminator Tape™ uses the Earth's magnetic field to generate drag to shorten the deorbit time of a spacecraft in LEO. It links to https://sst-soa.arc.nasa.gov/12-passive-...
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### Can impact lift produce greater than 1 lift to drag ratio?

At orbital velocity in low circular Earth's orbit, at an altitude where mean free path exceeds cross sectional area of a craft or wing. therefore aerodynamic lift becomes impossible (Consider ...
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### When do aircraft become solarcraft?

Any body travelling through particles undergoes drag. Any body able to generate lift (for instance spheres cannot generate lift) can generate lift if it undergoes drag. First by assuming one body in ...
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### 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 ...
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1 vote
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### Nano spacecraft reentry

Suppose if one designs a Small size reentry capsule. What will be the typical deacceleration achieved by atmosphere. More precisely, what is the relationship of the size and drag by atmosphere. I am ...
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### Reference frames - why do I need to convert to Geocentric Equatorial State Vector to solve equation of motion?

I am asking this question in relation to an example shown in the 'Orbital Mechanics for Engineering Students' book by Howard Curtis (third edition) pp659 example 12.1. The example is demonstrating how ...
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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_{...