Questions tagged [falcon-9]

Questions regarding the Falcon launch vehicle developed by SpaceX for medium payloads (15,000 lbs) to LEO and GEO (via GTO, second stage cannot inject into GEO direct)

Filter by
Sorted by
Tagged with
-1
votes
0answers
31 views

Falcon 9 temperature during launch?

When Falcon 9 is launching in orbit, what is the maximum temperature experienced by: payload fairing first and second stage outer layer Merlin engine nozzles
2
votes
2answers
115 views

Why Falcon 9 doesn't need heat shield tiles? [duplicate]

The Space Shuttle and the Starship need tiles for termal Protection while reentry. Why Falcon 9 doesnt need them?
7
votes
2answers
1k views

Why does the Falcon 9 use turbopumps as well as helium pressurisation system?

Falcon 9 first stage use turbopumps as well as helium pressurisation system. Isn't the turbopumps enough to pump in the propellants to the combustion chamber?
3
votes
1answer
58 views

How throttle changes affect calculations of thrust?

So, for constant throttle setting equation to calculate thrust looks like $ \ F = \dot{m}_\mathrm e V_\mathrm e + (p_\mathrm e - p_0) A_\mathrm e$ But if we are looking at flightclub.io simulation, ...
9
votes
0answers
145 views

Why is the water pumped out of the holding tank a minute before Falcon 9 liftoff?

SpaceX Falcon 9 - starlink mission on October 5. Video : Why is the water discharged at T- 01m:30s from the holding tank far away from the launch pad? This was also ...
3
votes
1answer
160 views

What is the Falcon 9 interstage used for?

What is the interstage used for, how big it is and is it deorbiting separately?
3
votes
2answers
333 views

What is the return speed of the Falcon 9 booster?

The Falcon 9 first stage detaches at about 70 km high and it descends in about 6 minutes. That means an average descending speed of 200 m/s But what is the maximum speed it reaches on descent? And ...
6
votes
1answer
337 views

Simulating launch velocity of falcon 9

Help! I finished my numerical simulation of falcon 9 launch in google sheets, where I calculate all the value changes with time. But, when I looked at real launch to compare the values, I got really ...
0
votes
1answer
70 views

At what time is the Falcon 9 loaded with fuel?

How long before launch are the fuel and oxidizer loaded into a Falcon 9 rocket? And how much time does it take to load it?
1
vote
1answer
79 views

How long it takes for the Falcon 9 payload fairings to reach the sea?

The payload fairings of Falcon 9 are released at about 3:15 min How much time they need to fall and reach the sea? And what is their maximum speed while reentry?
-1
votes
1answer
77 views

The numbers on the live Falcon 9 videos

In the live Falcon 9 launch videos there are two numbers displayed at the bottom-left corner of the screen. The two little circular and text gauges that have the units under them. I guess they are the ...
1
vote
1answer
88 views

Falcon 9 landing stages

I know the first stage of Falcon 9 separates at about 2:30 min and it lands at about 8:30 min But what are the distinct stages of the descent? Like deorbit burns, grid fin deployment, leg deployment ...
5
votes
2answers
125 views

Falcon 9 Merlin 1d thrust calculated through every moment of flight

I am currently trying to recreate the launch of falcon 9 in unity. For the calculations I need the thrust of the first stage (only doing it for one stage for now). How to calculate it depending on the ...
13
votes
2answers
2k views

Till what altitude above earth sounds can be heard?

In the new video of SpaceX SAOCOM 1B launch and landing RCS thrusters and other sounds can be heard during boostback burn. Falcon 9 boostback happens at nearly 100 Km altitude. Does the air density at ...
11
votes
2answers
1k views

Falcon-9/Starship landing on an uneven surface

I was wondering how a Starship or Falcon-9 booster could land on an uneven surface, like that of the Moon or Mars. Is the landing gear similar to the Boeing hydraulic landing gear, which cushions and ...
3
votes
0answers
115 views

How do Falcon-9's cold gas thruster maneuvers account for the center of mass changes due to “floating fuel shifts”?

The Art of Engineering video How SpaceX Lands Rockets with Astonishing Accuracy after 07:19 explains: Cold Gas Thrusters The falcon 9 is equipped with a total of ...
3
votes
0answers
74 views

What are the protrusions on the outside of the Falcon 9 nose fairing?

Near the base of the Falcon 9 nose fairing is an array of square protrusions (marked in red) that you'd probably want to avoid unless they serve a very essential purpose. Does anyone know what that ...
6
votes
0answers
68 views

SpaceX Dragon Shape: Power Series, Ellipsoid, or Haack/Von Karman?

The SpaceX Dragon module has a round apex typical of power series, ellipsoid, and Haack/Von Karman shapes. I'm wondering which of these SpaceX actually used. References would be appreciated. My guess ...
2
votes
1answer
115 views

Does Falcon 9's first stage use laser, radar or vision to assist landing? [duplicate]

Does Falcon 9's first stage use only GPS when it makes its vertical precision landing, or is it assisted also by radar or laser ranging or computer vision? If not, why not?
16
votes
0answers
161 views

What damage/repairs have to be done to the launch pad every time SpaceX launches?

As SpaceX is a company that is very focused on rapid reusability, low-cost operation and a philosophy of "the best part is no part", what repairs have to be done to the towers and general ...
4
votes
1answer
160 views

Is this soot building up on the Falcon 9 interstage?

In the below video of stage separation during Falcon 9's CRS-19 mission, the exhaust of Stage 2's Merlin 1D-Vac impinges on the interstage. It also deposits a black substance on the white paint. Is ...
9
votes
2answers
2k views

What happens to payload fairings of GEO launches?

Say you launch a satellite into GEO using Falcon9 The 1st stage returns The 2nd stage is moved into graveyard orbit. But what happens to the payload fairings?
5
votes
1answer
142 views

What prevents SpaceX from increasing the cadence of launches?

Many companies can afford and buy expensive launches (Ariane etc) so they prefer SpaceX to save money. Many other companies can't afford Ariane launches but they would afford Falcon 9 launches. Lower ...
3
votes
1answer
95 views

How many times can Falcon 9's payload fairings be reused?

Falcon 9's first stage can be reused 10 times or even 100 times. But how about its payload fairings?
1
vote
1answer
45 views

When does Falcon 9 second stage separate?

For a regular LEO payload, when does the second stage separate? Usually the first stage separate 2:30 min after launch (and it takes 6 minutes to come back to Earth) so how about the second one? ...
3
votes
2answers
593 views

Did SpaceX ever reuse payload fairings?

Did they ever reuse the payload fairings of the Falcon 9? There are a few related questions about maximum reuses and fastest refurbishment that might be asked later I guess
0
votes
3answers
140 views

Are Falcon 9 1st stages now always landed at sea?

Does the first stage of Falcon 9 now always land on a drone ships at sea? Say since 2016 or so.
5
votes
0answers
53 views

Electrical power requirements for Starship or Falcon 9

Anybody know where one could dig up electrical requirements for Starship? In other words, if Starship were sitting on the launch pad drawing power prior to launch, what would the load be? I imagine ...
4
votes
1answer
171 views

How long does the descent of the Falcon 9 first stage take?

After separating from the second stage, how long does it take for the Falcon 9 to come back to Earth? From LEO and from GEO. Note: this question is similar: How long does it take to recover the first ...
3
votes
0answers
47 views

Altitude at which Falcon boosters go subsonic during reentry

Is there a distinct altitude at which Falcon boosters goes subsonic during reentry? If so, which is it? Is it +/- the same altitude for every flight?
10
votes
1answer
525 views

Falcon 9 second stage roll control: fins or dracos?

Unlike the first stage, the second stage has just one gimballed engine, meaning it can counter pitch and yaw perturbations, but not roll perturbations. Fins are effective for roll control, but at 50 ...
5
votes
1answer
159 views

Why would the Falcon 9 Block 5 carbon fiber thermal protection material need to be hydrophobic?

This answer to Nature of “the silky black 'highly flame-resistant felt'” on Block 5 Falcon 9's, and its intended functions? contains the following: This came into Falcon 9 design with Block 5 ...
4
votes
0answers
62 views

how much force can a falcon 9 landing leg handle

According to spacex, the falcon 9 landing legs are made of carbon fiber with aluminum in a honeycomb shape. How much force would be needed to break that?
5
votes
1answer
88 views

Do the ASDS barges have mission specific equipment?

End of June 2020, there was a planned Starlink (L9) mission on Jun 26, and OCISLY (Of Course I Still Love You, name of the vessel, really! Not making that up!) went out catch the stage. Then a few ...
2
votes
1answer
100 views

What is the maximum apogee a Dragon spacecraft can reach?

What is the maximum apogee a Crew Dragon can reach in a highly elliptical orbit (by both the Falcon 9 and the Falcon Heavy)? There is a planned touristic mission in which the current apogee record of ...
1
vote
2answers
191 views

Were/Are the Space Shuttle or the Falcon 9 Dragon capable of achieving an elliptical orbit on whose apogee you'd see the entire Earth?

Was the Space Shuttle and is the Crew Dragon capable of achieving a highly elliptical orbit on whose apogee you could see the entire planet Earth? There will be a touristic flight soon in which an ...
6
votes
1answer
210 views

What is a “flight string”?

This answer explains what software powers the Falcon 9 launch vehicle. The flight software is written in C/C++ and runs in the x86 environment. For each calculation/decision, the "flight string&...
1
vote
0answers
61 views

Where will the DSCOVR mission Falcon 9 2nd stage rocket body end up?

This answer to Why would a mission to Sun-Earth L1 have an instantaneous launch window? suggests that this was quite a delta-v-intensive launch. It left the F9 2nd stage in a very high 17 day orbit ...
3
votes
0answers
101 views

Space-X Falcon-9 and Falcon Heavy fuel consumed for landing

The question is, how much fuel is used by each of above rockets for landing (in % of whole fuel of the rocket) as a function of three following components - payload, orbit and descend trajectory (land/...
3
votes
0answers
48 views

Where are Falcon 9 1st stage GN2 tanks located?

Is nitrogen propellant for the two cold gas thrusters pods contained in the interstage? The view we have from the B5-B1050 recovery shows several small COPV(s) pic1 Here you can see where the cold gas ...
12
votes
2answers
3k views

Why does the Falcon 9 launch 60 instead of 100 Starlink satellites at a time?

The Falcon 9 has a capacity of 22,800 kg to LEO. A Starlink satellite has a mass of 227 kg. That means that one Falcon 9 can launch 100 satellites. So why does SpaceX launch 60 instead of 100 ...
5
votes
1answer
150 views

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--...
7
votes
1answer
133 views

Falcon 9: Why does F9 first stage always lose Video Link during Entry Burn?

Typically the F9 first stage and the drone ship each lose the video connection once during landing: F9 first stage during entry burn Drone ship during F9 first stage touch down (see here and here) ...
11
votes
1answer
106 views

What factors do (or are expected to) limit reuse of a Falcon 9 block 5 first stage?

SpaceX have claimed (reported here) that the Falcon 9 Block 5 first stage should be reusable up to 10 times without significant refurbishment, and up to 100 times in total. What factors are expected ...
3
votes
1answer
104 views

What are the needle pins that go through the pneumatic pushers of the Falcon 9 fairing?

The Falcon 9 fairing uses four pneumatic pushers to impart a positive separation force between the fairing halves. The pushers all mount on half of the fairing and push against the other half. But ...
4
votes
1answer
185 views

What are these cartridges with holes on the Dragon trunk?

You can see them on the rim in a hexagonal pattern in the picture below. Also present in the latest version of the Dragon trunk, but less clearly than here. They alternate in color from nickel to ...
5
votes
3answers
346 views

How does SpaceX Falcon 9 keep balance while it is near to the landing site?

As we know, flight vehicles can't keep balance easily if they cannot propel enough air through their blades or wings. We can also see the Falcon 9 at a steeper angle a while before touching down on ...
4
votes
1answer
133 views

From what material and how are the Merlin engines and nozzles of it (sea level) manufactured?

I am specifically interested in the alloy used to build the engine, also about the nozzle: Is it just in one piece or welded using different sections. If they are welded then which welding techniques ...
4
votes
1answer
109 views

Crew dragon falcon 9 first stage shut down

Crew dragon falcon 9 first stage shut down around 6700 km/hr and starlink shut down around 7900 km/hr, but around the same time. Is this because the crew dragon weighs more?
6
votes
1answer
122 views

Is the Falcon 9 second stage engine throttled down to limit maximum acceleration

Is the Falcon 9 second stage Merlin vacuum engine throttled down during its burn to limit the maximum acceleration experienced by the Dragon or Crew Dragon capsule? As the second stage consumes ...

1
2 3 4 5
11