Water based rocket launches

[scola_p]

Randomly browsing the Web on dull call (5pm on a Friday - who does that?) and I spotted this.

https://www.inverse.com/amp/article/21071-well-why-don-t-they-just-build-the-whole-rocket-out-of-the-ocean-then

Sounds far fetched, but very kerbal. 

Any takers for a prototype?

P

[Choctofliatrio2.0]

What's the purpose of it? Like, how is it better than a normal launchpad? Not as much hardware to maintain on the ground, but I'm sure making ballast systems and engines that seawater won't obliterate would be pretty costly.

[SpacedCowboy]

Very interesting and yes, very kerbal. Watching the video I expected to see some kind of floating launch platform.

Instead, they tow the rocket out to sea with a tug boat ( which was a little strange ) and the rocket uprights itself, half submerged, and off it goes.

Yeah, very kerbal.

[Kerbart]

Sea Launch has been doing this for years. Nothing new about it.

Edit: Oh wait, without a launch pad? Interesting. Not sure what the benefits are (having to waterproof the rocket, etc) but there's a charming advantage in simplicity.

Edited September 16, 2016 by Kerbart

[septemberWaves]

The obvious benefits seem to be cost savings on maintaining the launchpad (since there's no launchpad to refurbish each time), the ability to launch quite easily into just about any inclination without having to use a dedicated launch site or conduct an inclination change in orbit, and possibly some natural acoustic suppression because of the water.

[Pecan]

Can't see it myself - the rocket would have to be quite robust to work as a barge while it's being towed.  Robust = heavy = not good for flying, in this case.
Then it points itself at the sky, which would imply it's pumping sea-water into the rear to act as ballast = heavy = not good for flying or much else.

Sure I'm missing something.

[Kerbart]

4 minutes ago, eloquentJane said:

The obvious benefits seem to be cost savings on maintaining the launchpad (since there's no launchpad to refurbish each time)

But do those savings offset the cost and mass associated with constructing a waterproof rocket that launches with comparable reliability?

4 minutes ago, eloquentJane said:

, the ability to launch quite easily into just about any inclination without having to use a dedicated launch site or conduct an inclination change in orbit, and possibly some natural acoustic suppression because of the water.

Those apply as much to launching from a floating launchpad.

[septemberWaves]

@Kerbart those are some very good points. Presumably the company intending to use this rocket design have a way of doing it that will in theory lead to profits. Perhaps it's something to do with the propulsion systems that the rockets use: it appeared that the lower stage uses an aerospike and the upper stage uses a flattened aerospike-derived design. Aerospikes are generally used in designs where altitude compensation is important, and perhaps they have designed some that have incredibly good I_sp compared to alternatives. It doesn't necessarily explain why they choose to launch it from water, but it could be a reason why this rocket may be cost-effective.

[AlexisBV]

21 minutes ago, eloquentJane said:

and possibly some natural acoustic suppression because of the water.

The fish would probably disagree. I didn't see anything about impact on ocean life, but judging from youtube videos on the effects of lights at night + firecrackers, it's probably non-negligeable.

[Technical Ben]

Oh, any shoals of fish/whales etc would die in quite a close and somewhat those far.

Sonar is loud enough to deafen Dolphins.

 

Edited September 16, 2016 by Technical Ben

[Deddly]

When I opened the link, the first word I saw was "Spaceflight", so that gave me a clue where to move the thread

[DDE]

Water launch is the key to Big Dumb Boosters like the Sea Dragon, since they'd be built in shipyards out of regular 8 mm steel.

[Bill Phil]

Ah, a return to old ideas yet again. Let's hope they can make it work, somehow.

[_Augustus_]

55 minutes ago, DDE said:

Water launch is the key to Big Dumb Boosters like the Sea Dragon, since they'd be built in shipyards out of regular 8 mm steel.

I'm never going to understand why we don't adopt those monsters. You could do a MARS DIRECT LANDING AND RETURN IN ONE LAUNCH, people!

[septemberWaves]

Just now, _Augustus_ said:

I'm never going to understand why we don't adopt those monsters. You could do a MARS DIRECT LANDING AND RETURN IN ONE LAUNCH, people!

You say that, but keeping the crew alive and healthy for that time period would be incredibly difficult with a single launch, even with that sort of payload mass. The moon landings were doable whilst keeping the astronauts in microgravity for most of the time, but a crew travelling to Mars will pretty much require some method of generating artificial gravity in order to ensure that they are able to move around when they get to the surface of Mars and also back to Earth.

[_Augustus_]

8 minutes ago, eloquentJane said:

You say that, but keeping the crew alive and healthy for that time period would be incredibly difficult with a single launch, even with that sort of payload mass. The moon landings were doable whilst keeping the astronauts in microgravity for most of the time, but a crew travelling to Mars will pretty much require some method of generating artificial gravity in order to ensure that they are able to move around when they get to the surface of Mars and also back to Earth.

It's called tethering your transfer vehicle to the upper stage. Just like Mars Direct.

[DerekL1963]

14 minutes ago, _Augustus_ said:

I'm never going to understand why we don't adopt those monsters.

Simple.  They're going to be extraordinarily expensive to develop and build and basically don't have any use.  Kinda like the Senate Launch System.

[Bill Phil]

23 minutes ago, _Augustus_ said:

I'm never going to understand why we don't adopt those monsters. You could do a MARS DIRECT LANDING AND RETURN IN ONE LAUNCH, people!

Money. It would take a lot of it... But the cost per kilogram is on par with current launch vehicles (according to estimates...)

[tater]

As long as we're indulging waterborne fantasies... Boeing LEO.

 

 

Landing...

 

 

 

Edited September 16, 2016 by tater

[DDE]

11 hours ago, Bill Phil said:

Money. It would take a lot of it... But the cost per kilogram is on par with current launch vehicles (according to estimates...)

It's also about spreading the pork. NASA would have to dump a large portion of its suppliers... and of course the Congress isn't gonna let it.

[Kryten]

The one in the OP looks about as likely to launch something into orbit as I am.

I mean, just look at their website; http://www.ripple-aerospace.no/

There's almost no information, and the whole thing looks like engineering by design students. Major details are missing or are barely mentioned, like the fuel combo they intend to use; which, by the way, is hydrolox. How the hell is a sea-launched vehicle supposed to be filled with liquid hydrogen without turning into the world's largest ice lolly or wiping out all the payload mass with insulation?

[YNM]

I don't get it - Unless the rocket is full of gaseous air, it's going to be heavier than water right ? How in the hell they haven't think of that ? Even SLBMs can only get off water by some pushing mechanism (air) or engines, are they going to tow it on a boat fully laden ?

Edited September 17, 2016 by YNM

[Kryten]

2 minutes ago, YNM said:

I don't get it - Unless the rocket is full of gaseous air, it's going to be heavier than water right ? How in the hell they haven't think of that ? Even SLBMs can only get off water by some pushing mechanism (air) or engines, are they going to tow it on a boat fully laden ?

Hydrolox is heavily biased towards liquid hydrogen, which is far less dense than water (70g/l v. 1,000g/l), so that bit at least checks out.

[YNM]

2 minutes ago, Kryten said:

Hydrolox is heavily biased towards liquid hydrogen, which is far less dense than water (70g/l v. 1,000g/l), so that bit at least checks out.

Hmm... didn't really know that, thought it would use kerolox (as hydrolox would need some massive tanks).

Still, a lot of things needs to be figured out.

Edited September 17, 2016 by YNM

[A Fuzzy Velociraptor]

A full length spike... Clearly such a long thin thing won't have any sort of structural issues or logistical issues, and certainly having so much exposed area in our exhaust stream won't make cooling the thing a problem at all, especially when you consider all the benefits that a full length spike will give over a 23% "isentropic" aerospike like 1-2% higher performance (less if you dump a bit of exhaust into the center of the aerospike stream).

Edited September 17, 2016 by A Fuzzy Velociraptor