# Tag Info

58

The fairings are not boats. While they appear to float (at least for some time), there will also be water on the inside of the fairing. That results in some issues. Inside the fairing, there are electronics and other corrodable materials. Now the fairing is designed to be as light as possible. Therefore, SpaceX probably doesn't want to make the entire ...

56

One of the keys to SpaceX's cost advantage is standardization on common parts. One example is the Merlin engine, which is used on both the first and second stages of the Falcon 9 and Falcon Heavy (though a slightly different vacum optimized version on the second stages). This is also done for fairings. Fairings are very expensive to make (around $6M). ... 39 It would only make sense to keep the fairing attached if the stage it was attached to was going to be recovered. The SpaceX falcon and falcon heavy are multi-stage rockets, only the first stage is reusable. The fairing is jettisoned once the aerodynamic pressure is low enough it isn't needed anymore, which is before orbital velocity is reached. Because it's ... 38 In addition to the water damage is the impact damage: the fairings wouldn't "touch" the water they'd hit the water, even with parachute retardation. A net slows deceleration down and spreads it more evenly across the structure, which is a lot friendlier to the materials and the supporting electronics. 35 There are a few basic reasons. These include: The aerodynamic model of a fairing needs to be redone with a new fairing design The fairing volume provides a space to ensure the satellite is kept cool while on the ground. This would be considerably more complex if the satellite was the fairing, it would have to be kept cool on the ground and yet be fine to ... 30 It is not so much that in the 21st century it is hard or expensive to make a fairing. Rather they are just REALLY REALLY big. 13 meters by 4.6 meters. That is about 40 feet long, and 14 feet wide. The common description is that a school bus would fit in it. (Sort of like the Space Shuttle cargo bay size). These need to be very light, as every gram/... 25 The fairings are detached to prevent carrying their un-necessary mass to orbit. This typically happens during the second stage burn. See this question for information about the timing of fairing jettion: How strong and "hot" is the wind on the payload after the fairing is deployed at ~110km? An image showing the fairing separation during the ... 24 Supplementary to other answers which describe why most payloads aren't their own fairings: We do actually launch some payloads that are somewhat closer to being their own fairings - manned spacecraft. This is usually because the spacecraft's reentry vehicle is already designed to be heat resistant and aerodynamic, making it more suitable for launch ... 23 The plan as has dribbled and drabbled out from Musk's various statements is that the fairings are large and light, thus reentry heating is not too bad on them. They do not need to do a re-entry burn as the first stage seems to require, in order to slow down enough that hitting the atmosphere does not melt the entire structure. Then once in thicker air, a ... 22 A fairing like the one SpaceX uses on the Falcon 9 weighs on the order of 2 tons. That's a lot of extra weight to add to the satellite. Satellites are usually covered in components that need to be exposed to space: solar panels, radiators, antennas for example. Solar panels and radiators could be installed on the outside of the fairing, but then you'd ... 20 The fairings are large structures, made in a way that's difficult to automate. The structure consists of an aluminium honeycomb core with carbon fibre inner and outer panels laminated onto it. Carbon fibre is a labor-intensive material. Then there's the quality assurance that makes everything rocket-related expensive. Roof boxes, OTOH are injection ... 19 The JWST is made to fold up, to fit inside the standard fairing. You can sort of see this in your image, 3 mirror segments are visible (the hexagons in the middle), other segments are viewed side-on and aren't visible. Folding animation Time lapse showing the folding during assembly 15 Apparently this was considered by SpaceX in Q1 2015, to work around a production bottleneck. Due to delays in 2015 after the June 2015 loss of CRS-7 that bottleneck may not have occurred. As of CRS-8 (1 year later) we haven't seen a recovery attempt but it's still something SpaceX wants to do. This slide is from an internal SpaceX presentation: SpaceX ... 14 While I have no specific knowledge of Falcon 9's fairing, it is common for compartments of space vehicles to be purged or pressurized slightly above ambient while on the pad to keep contamination out of the vehicle. After launch, vents allow the pressure in the compartments to drop in a controlled fashion as ambient pressure drops. To get a feel for how ... 14 Launch vehicle operators (or at least the major ones) all seem to drop their fairings such that the heat produced by the remaining atmosphere remains below 1135 W/m$^2\$. Not all the operators provide details on how heat is calculated, but those that do say that the heat flux is calculated using a free molecular flow through a plane perpendicular to the ...

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The fairings cost several million dollars. During the post launch briefing of CRS-8, Elon Musk mentioned that: A few more things we want to do... we want to try to bring back the fairing - the big nose come back. That will certainly help because each of those cost several millions. Midair helicopter capture would be tricky. Is there such a ...

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The fairing itself is large, (a pair can enclose a school bus sized payload) and is very light, and not very aerodynamic when split into two halves. When joined together it is very aerodynamic, when split apart, dramatically less so. Thus the parachute has to overcome a very oddly shaped, unoptimized for gliding shape. It is fairly large, ungainly, and ...

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One of the biggest concerns in spacecraft is keeping them free of contaminants. Spacecraft are often built in clean rooms to keep them free of any such thing. Landing in salt water would leave residue on the fairing that would be virtually impossible to clean. Outgassing from any residue could lead to damage to the payload. Source.

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Apart from the mass penalty of carrying the fairing through the entire flight that Organic Marble mentioned, a hinged fairing and the mechanism to open and close it would be much more expensive, massive, and unreliable than the simple spring or explosive ejectors used on current rockets. You don't want to get the upper stage all the way into orbit and then ...

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The fairing consists of an aluminium honeycomb sandwiched between carbon fibre sheets. The amount of air trapped in the honeycomb determines if the structure will float, but as we don't know how thick the honeycomb and the CF cheets are, there's no way to say for sure whether it'll float. The shock of landing may damage the fairing, but we don't know its ...

10

That ULA video was great. I googled for "fairing vibrational modes after jettison" and came up with a lot of interesting links. The prize is probably this paper "Simulation of the behavior of a payload fairing during separation" which includes this graphic showing motion just like what's in the video. and this description The vertical jettison ...

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Are launch fairings pressurized to 1 atmosphere for the benefit of the cargo? No, pressure within the fairing will drop gradually during the launch. The reason for the pressurization system is to control the pressure change, to protect the cargo from sudden changes. The Falcon 9 User's Manual has a section on "Fairing Internal Pressure", which describes ...

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Repeatability The fuel for a launch is factored by a few things, including the mass and aerodynamics. You may save some mass by not having a separate fairing - but you have a different-shaped nose each time, with different aerodynamic properties. This would require re-analysis of the new profile each time, but with the generic nose you already know drag ...

8

Q: "On the descent of the fairings into the atmosphere how the stability is provided? Does not start to rotate in a uncontrollable fall but reentry gently without apparently damages on the interior side.". Source Elon Musk InstaGram: A: "It has onboard thrusters and a guidance system to bring it through the atmosphere intact, then releases a parafoil and ...

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The current theory (no evidence, since SpaceX is somewhat close mouthed on this topic) is that they are demonstrating that they can catch one, first. Once they understand the process, they will figure out how to do both. In fact there have been comments from Musk that only one half is even instrumented to be recovered right now. Boats are well understood ...

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While we wait for an authoritative answer, I'm going to guesstimate here, and answer your second question in the process. "Is this resting on something, or is it really floating this high in the water?" I'm going to assume you are refering to the first picture here, it is pretty clear that it is suspended from something in the other two. If we look closely ...

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Have a look at this video. You can see one of the fairings stabilizing itself with a thruster around 04:00. Start watching after 02:44 when the 2nd stage engine ignites. It looks like the bright spot at the top is the 1st stage, using cold gas thrusters, and the bright one at the bottom is the 2nd stage continuing. The two smaller spots are the fairing ...

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The ultimate plan is to catch both of them, on ships like Mr Steven. Aug 2019 update: Mr Steven's owners went bankrupt and sold the ship to GO, who operates the rest of the SpaceX fleet GO renamed it to Ms. Tree (Mystery). A similar ship has been brought into the GO fleet as Ms. Chief (Mischief). Thus the second ship has arrived to catch fairings. As of ...

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...is there a gap in my thinking? ...assume the reconnect occurs long after the rocket has engaged the next stage... I think there's the gap. The payload fairing is typically deployed while the second stage is still firing. See this example during the first Falcon Heavy flight. ...and that the tether(s) is designed in such a way that it avoids ...

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A document from NASA Safety & Mission Assurance suggests the reason is structural: Thin-­skinned Centaur cannot easily support the giant 5.4 meter diameter payload fairing, so the Contraves composite fairing also encloses Centaur. My first guess, however, was aerodynamics, particularly the Whitcomb area rule: for transonic flight, abrupt changes of ...

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