F9 Performance improvement with 4 meter fairing

[wannamoonbase]

All, forgive me if this has been discussed and/or if I kick off a thread that goes wild and strays into annoyance.[/size]


Mods, delete or merge if you see fit.I have been thinking about the upper stage with the shortened nozzle and fairing recovery.That got me to wondering if there would be a case to be made for a smaller diameter payload fairing. SpaceX was very smart to do a 1 size fits all payload fairing to manage costs when they were financially constrained and didn't have as large a manifest.  However, with a high flight rate and fairing recovery could a performance improvement with a smaller fairing that is lighter and allows for a smaller throttle bucket around Max-Q that would allow for more use of the shorter US nozzle and or more booster RTLS flights.Or is to negligible?


Thanks for indulging.

[alugobi]

Too negligible.  And too much refitting for a steady-state system that is slated for retirement. 

Just doesn't seem to fit with the SX method.

[abaddon]

Too negligible.  And too much refitting for a steady-state system that is slated for retirement. 

Just doesn't seem to fit with the SX method.

One could say the same thing about the short vacuum nozzle, and yet here we are...

Yet, I agree, because a new fairing would presumably be much more expensive to qualify and riskier than the short nozzle.  SpaceX is already going to be offering a new bigger fairing as a requirement of NSSL, I don't think they want to add another new smaller fairing for marginal benefit.

[TrueBlueWitt]

Too negligible.  And too much refitting for a steady-state system that is slated for retirement. 

Just doesn't seem to fit with the SX method.

One could say the same thing about the short vacuum nozzle, and yet here we are...

Yet, I agree, because a new fairing would presumably be much more expensive to qualify and riskier than the short nozzle.  SpaceX is already going to be offering a new bigger fairing as a requirement of NSSL, I don't think they want to add another new smaller fairing for marginal benefit.

Smaller diameter fairing would also have higher reentry heating. Might not be reusable or recoverable

[kevin-rf]

Since gen v2 Starlink mini's would potentially be the largest user, a shorter 5m fairing would most likely give SpaceX more bang for it's buck. They are width constrained, not length.

[Barley]

Smaller diameter fairing would also have higher reentry heating. Might not be reusable or recoverable

Please explain.

A fairing is not a solid object.  If the wall thickness is the same a small and large fairing would have the same mass/area.  If anything a smaller fairing should have thinner walls because the greater curvature makes it stiffer.

[alugobi]

Too negligible.  And too much refitting for a steady-state system that is slated for retirement. 

Just doesn't seem to fit with the SX method.

One could say the same thing about the short vacuum nozzle, and yet here we are...

Yet, I agree, because a new fairing would presumably be much more expensive to qualify and riskier than the short nozzle.  SpaceX is already going to be offering a new bigger fairing as a requirement of NSSL, I don't think they want to add another new smaller fairing for marginal benefit.

Tin snips in the first case (generally speaking).  New molds and tooling in the second, and, possibly, a testing regimen.

Fixing too much that isn't broken.

[Zed_Noir]

In theory for high energy mission with small spacecraft that can fitted in a 4 meter diameter payload fairing. Could put the old 4 meter payload fairing for the Atlas V 400 series on top of a Falcon 9 or Falcon Heavy with an adapter ring section.

In theory, since no one will likely want to qualified the old Atlas V payload fairing for a very few missions with the Falcon 9 or Falcon Heavy.

Will be interesting to see something like the New Horizon spacecraft riding out on a fully expendable Falcon Heavy with a small and asymmetrical payload fairing.

[wannamoonbase]

Too negligible.  And too much refitting for a steady-state system that is slated for retirement. 

Just doesn't seem to fit with the SX method.

One could say the same thing about the short vacuum nozzle, and yet here we are...

Yet, I agree, because a new fairing would presumably be much more expensive to qualify and riskier than the short nozzle.  SpaceX is already going to be offering a new bigger fairing as a requirement of NSSL, I don't think they want to add another new smaller fairing for marginal benefit.

Tin snips in the first case (generally speaking).  New molds and tooling in the second, and, possibly, a testing regimen.

Fixing too much that isn't broken.

I'm not suggesting they are going to do this, I interested in the amount of performance improvement and whether it can enable shorter nozzle US or RTLS flights.

I think you are overly optimistic on the F9 retirement as well.  Starship is still a ways off from being operational or having a flight cadence to take over for F9, probably 3-5 years.

A 4 meter diameter fairing would be thinner, shorter.

SpaceX has redesigned the current fairing multiple times for manufacturing costs and reusability.  producing a new 4 meter fairing could be done easily compared to what they have already done. 

May not be worth it, but the performance would be fun.

[alugobi]

I think you are overly optimistic on the F9 retirement as well.  Starship is still a ways off from being operational or having a flight cadence to take over for F9, probably 3-5 years.

I made no timeframe speculation.  I don't know how long it will be.

How many times would the proposed changes be used until then?  Don't know that, either.  Just doesn't smell like something they'd pursue, with the resources they're pouring into BC and maybe, eventually, the Cape.

[whitelancer64]

I think if it made sense, SpaceX would have done it before now. They've launched several very small payloads that barely took up any space within the existing fairing. My guess is that it is very much cheaper and easier to recover and reuse the existing fairing design than to design, build, and qualify a new one.