Questions tagged [grid-fins]
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32 questions
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Why Did Starship 3 launch with its Hypersonic Grid Fins fully deployed?
Wouldn’t having the grid fins extended from launch to booster separation just cause extra drag?
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How to approximate the force generated by Falcon 9 grid fins?
I'm interested in approximating the force generated by the grid fins on a Falcon 9 rocket during its descent phase. However, I currently lack specific data and equations for this calculation. Can ...
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When chopsticks catch the booster by the grid fins, what is the maximum vertical speed?
How much vertical speed can the grid fins handle before breaking off?
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CZ-4B Grid fins
In nov 2019 and sept 2020 the CNSA launched CZ-4B Y38 and CZ-4B Y41. Based on different images I noticed that this Long March 4B had grid fins. On CZ-4B Y41 the grid fins from Y38 were reused making ...
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Do Falcon 9 grid fins lock up during reentry?
Do Falcon 9 grid fins lock up when extended during reentry? Or do they rely on aerodynamic forces to keep them extended once they're deployed? Could the fins flail down during the reentry burn when ...
user39728
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Falcon 9 cold gas thrusters: why in line with grid fins?
The cold gas thrusters of the Falcon 9 are right in line with the grid fins.
The grid fins deploy immediately after MECO and stay deployed while the cold gas thrusters fire.
And it seems the expelled ...
user39728
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Why do Falcon 9 grid fins open in piecemeal fashion?
The grid fins on Falcon 9 seem to open in piecemeal fashion: extending a few degrees, pausing, extending a few degrees, pausing, etc.
Any reason why this happens? The rocket stage is around 80 km high,...
user39728
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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 ...
user39728
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Can the grid fins affect the rotation of the Falcon 9 descent?
Can the grid fins control the rotation of the Falcon 9 on descent?
How would they have to be positioned to stop the rotation?
If used to rotate the ship, then how they would they have to be positioned ...
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How do Falcon 9 grid fins deploy?
Is it aerodynamic drag that flaps the grid fins open? Or is there a controlled mechanism for it? Pictures show the grid fins connect through a small link to something inside the rotating trunnion arm--...
user36480
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Are these statements about "a first use of grid fins by China" simply wrong?
Ars Technica's Rocket Report: China discovers grid fins, NASA acknowledges Starship program says:
China experiments with grid fins. The launch of a Long March 2C from Xichang last week included a ...
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How much do SpaceX's titanium grid fin geometrical parameters measure?
Does anyone know approximately what is the width, length, thickness and depth of the titanium grid fins used in the Falcon9 v1.1?
I'm trying to make a 3D model on solidworks but can't find the ...
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What is producing these strange lights around the Falcon 9 grid fins (Starlink launch)?
Early in the video of the launch of the first sixty SpaceX Starlink satellites we can see that after stage separation the first stage grid fins open.
Around that time there are some phenomena I don't ...
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Will the New Glenn have grid fins? Why or why not?
The January 2019 Blue Origin video New Glenn: The Road to Space shows the rocket with static fins at the bottom and four articulated fins near the top of the first stage.
Is this just notional, or ...
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What light was the Falcon 9 grid fin occulting in todays SpaceX Nusantara Satu Mission live broadcast?
What light was the Falcon 9 grid fin occulting in todays SpaceX Nusantara Satu Mission live broadcast?
I backed up the time slider on the YouTube live broadcast and snapped some screen captures, ...
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Is helium used to power the Falcon 9 grid fins?
Is helium used as a hydraulic fluid to power the grid fins? Or for engine gimbaling?
What are the pros and cons of using helium instead of hydraulic fluids?
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Could SpaceX's grid fins be controlled by electric motors instead of hydraulics?
There have been a few instances of landing failures related to the grid fins and their hydraulic control - one where the hydraulic fluid ran out, and the latest one where a hydraulic pump stalled.
...
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Why didn't Saturn V have grid fins? Long March and Soyuz do!
From the question What are these four “waffle-like” structures on top of the Long March 2F just launched? and @RussellBorogove's answer there we can see that the Long March 2F carrying the Shenzhou-11 ...
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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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Is there any flutter analysis available regarding Falcon's grid fins?
I have never come across any papers which talks about flutter analysis of gridded fins in general, does it not under go flutter behavior or is it technically incorrect to talk about flutter for ...
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On the Falcon Heavy, why are the side boosters using Ti Grid fins, but not the center core?
Elon Musk showed a picture of the almost ready to fly Falcon Heavy in the HIF (Horizontal Integration Facility, aka rocket barn).
You can see the darker, larger grid fins on the side cores, and the ...
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Why are the new Titanium Grid fins not used on all Falcon 9 landings?
With the Block 4 version of the Falcon 9, one of the new features is the Titanium Grid fins, vs the previously used Aluminium fins.
However, not all Block 4 flights have used the Ti vs Al fins.
Is ...
- 80.5k
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What would the reference length be for a grid fin?
I am using this Atmospheric Properties Calculator to find the condition a grid fin would encounter when it has a altitude of 86km, and velocity of 7996 km/h. Would this be the total surface area of ...
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How do the F9 grid fins extend and rotate?
How do the F9 grid fins extend and rotate?
When the vehicle launches they are flat against the surface of the vehicle.
As the first stage begins reentry, the fins extend and start 'flying' the ...
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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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What do the Teeth on the SpaceX Falcon Mod4 do?
Can someone explain the purpose of the 'teeth' seen in the last picture of this answer?
Do they have a specific name? They look too far up to be used to grab anything since the rockets land ...
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How are the SpaceX Falcon 9 Mod 3 and Mod 4 grid fins different?
Elon Musk tweeted "Flying with larger & significantly upgraded hypersonic grid fins. Single piece cast & cut titanium. Can take reentry heat with no shielding."
These have been commonly known ...
- 80.5k
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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 ...
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What's behind the design of SpaceX grid fins?
These grid aerobrakes/drag control moving surfaces, have been used for a while on various aerodynamic designs, and presumably they provide a turbulent airflow, which in some way is more predictable ...
user19132
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Why did the grid fin of the CRS-8/SES 10 booster burn?
After a successful reentry burn of the stage, around 10 seconds after engine shutdown, one of the fins glows red, then begins to burn. My question is why would this burn after the stage already ...
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Is SpaceX grid fin material flammable?
I was looking at the Thaicom 8 falcon 9 launch and landing, trying to get a bit more info about the trajectory the first stage takes. The camera is however damaged and we miss most of the atmospheric ...
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What are these four "waffle-like" structures on top of the Long March 2F just launched?
Near the top of the Long March 2F rocket (middle of the fairing?) that launched today with the Shenzhou-11 crew, there are four square wafffle-like structures that remind me of grid fins.
What are ...
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