Questions tagged [grid-fins]

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3
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0answers
81 views

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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0answers
93 views

What caused 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 ...
5
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3answers
211 views

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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130 views

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, ...
3
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2answers
227 views

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?
4
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1answer
200 views

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. ...
12
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1answer
1k views

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 ...
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 ...
4
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0answers
163 views

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 ...
19
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2answers
3k views

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 ...
5
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1answer
1k views

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 ...
3
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1answer
141 views

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 ...
3
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1answer
538 views

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 ...
5
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1answer
579 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?
16
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1answer
1k views

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 ...
24
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2answers
13k views

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 ...
4
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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 ...
2
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2answers
1k views

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 ...
21
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2answers
3k views

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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2answers
1k views

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 ...
8
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1answer
452 views

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 ...