# Why doesn't SpaceX deploy some module to cover whole fairing like a rain coat just before sea landing? [duplicate]

In order to avoid fairing to get wet in water, why can't SpaceX just deploy something such that when fairings separate from the Falcon 9 then from inside some raincoat type waterproofing to just cover the whole fairing and let it fall on the water.

Then would not need to have a boat like Mr Steven? Would that be a simpler, cheaper solution?

The last launch which was on 25th July, Payload was 9,600 kg to LEO, and second last launch which was on July 22 Payload was 7,075 kg to GTO, where Falcon 9 Payload capacity to GTO and LEO is 22,800 Kg and 8,300 respectively.

As according to last two launches there is enough additional space left for adding any small stuff, the weight of adding the material to cover the whole fairing must be addable in that range I think, so overall there will be no cost for extra fueling or something, the only cost for SpaceX will be to build this material which will be very cheap, also a nose cone costs around $6M and the material cost will be very cheaper than that cost, also when SpaceX will be able to catch the fairings then they can stop adding this module but currently as they are losing $6M why not use an approach like this?

Note: The question Why can't Falcon 9 fairings touch the water? answers the why. My question is about a method to prevent that.

## marked as duplicate by peterh, Nathan Tuggy, Mark Omo, JCRM, MachavityAug 3 '18 at 13:11

• The answer is probably "weight". See this question. – F1Krazy Aug 1 '18 at 13:24
• What substance would you suggest that 1) is light 2) can withstand hypersonic air loads 3) can withstand reentry heating 4) is not affected by sea water. – Organic Marble Aug 1 '18 at 14:04
• on the inside of the fairing you have sound-absorbent panels, IIRC. These are most likely porous. Putting a watertight cover over them would defeat their purpose. – Hobbes Aug 1 '18 at 14:39
• @DaGroove Sorry, what thing? – Sudhanshu Gaur Aug 1 '18 at 17:02
• "there will be no cost for extra fueling" – How did you come up with that conclusion? Unless your fairing-fairing is made out of some magical material, it will weigh something. Remember, the fairing is the size of a large bus! You will need fuel to carry this fairing up. And then you need fuel to carry that extra fuel up. And extra fuel to carry up that extra fuel for that extra fuel. And so on. That is the tyranny of rocketry. Since you probably cannot just put more fuel into the rocket, this has to come from somewhere else: you need to either reduce the payload to orbit (which means … – Jörg W Mittag Aug 2 '18 at 7:56

The goal of a fairing is to make it as light as possible. The design they have chosen is most definitely not waterproof. There is a sandwich of aluminium and composites, which water getting in between is quite bad. Perhaps they could try waterproofing that area.

But the biggest reason is weight. The more complex you make it, the more you add to it, the heavier it gets, and the more it eats into your payload.

Now SpaceX is clearly willing trade performance for reuse, after all an ASDS downrange landing or RTLS landing eats between 15-30% of the payload possible on a fully expended mission.

Others have noted that as soon as a fairing gets wet, even if it is waterproof, there is salt residue that can be left behind that needs to be cleaned off. This adds to recovery cost as well as it is likely never as simple as hose it down, when it comes to aerospace equipment. Remember that upon use, this fairing encloses a very sensitive payload that is likely not happy with any contamination.

Additionally, while water contamination is a problem, the impact on the water is sufficient to damage the fairing, regardless of how intact it looks in pictures.

A parachute landing while 'slow' compared to orbital speeds, is NOT slow, when considering a large (School bus sized), not very stiff composite structure hits the water, it is way too fast.

Thus Mr. Steven includes a large net, with a very large amount of 'spring' in it.

You can see in this image, where a fairing is dropped into the net for testing, while on shore.

• Can you please see my edited post, thanks for helping :) – Sudhanshu Gaur Aug 1 '18 at 14:00
• @SudhanshuGaur many payloads have plenty of mass budget to spare (eg. TESS), but some do not. Since SpaceX's goal is reusability, standardisation and mass-production of parts, using different fairing designs for each launch isn't something they want to do. – Jack Aug 2 '18 at 9:28
• Yeah, thanks for telling, I was just curious that if a nose cone is worth $6M and till now if they had catched even 10 of them where payload size will be less than capacity, then $60M that;s great lot of sum. – Sudhanshu Gaur Aug 2 '18 at 10:04