arca steam powered booster?

[Flying dutchman]

 

 

https://www.youtube.com/redirect?v=zV8j08mCBEs&event=video_description&redir_token=NC7lEOfujz5jmfsuwala9R5Iz6x8MTU1Njk4ODAxMEAxNTU2OTAxNjEw&q=http%3A%2F%2Fwww.arcaspace.com%2Fdocs%2FARCA_LAS_White_Paper_May_1_2019_Issue_1.pdf

 

performance sheet etc.

 

i like the idea but with an isp of just 50 seconds it seems to me that you might just as well use cold gas engines since cold gas thrusters get an isp of aprox 70 sec

 

 

 

[DDE]

This is what you get when you obsess over one design element - low propellant cost - to the detriment of all others.

And then sell the result to the laymen.

 

1 hour ago, Flying dutchman said:

i like the idea

But how do you like corrosion by non-distilled, boiling water? Especially salty one?

[Flying dutchman]

I gues that's their problem to solve :p

 

[Cunjo Carl]

I like how their device for crashing kilotons of lithium batteries into the oceans is being framed as the environmentally conscious route! They have later plans to go reusable, but still

I feel like it'd make an awesome model rocket though.

[Scotius]

Using water as an propellant, or rather reaction mass does have sense. Water IS cheap and plentiful everywhere (almost) beyond Earth's orbit. Insulate it, and you can keep it frozen as long as you need, without worrying about boiloff (looking at ya there, hydrogen ). But... to get any serious mileage out of this heavy, dense lump of mass you need a ridiculously strong drive. Orion drive for example. Or saltwater nuclear engine. I guess maybe conventional thermal reactor of very high power could do in a pinch. Turn a small lake of water into sufficiently hot plasma and you're ready to go anywhere you want

But chemical rocket? Or even electric one? No - i don't see it happening.

Well... you could use it as a fuel source i guess. Just find a space iceberg floating around, drag it somewhere convenient, pour a lot of electricity into electrolysis factory and enjoy your fresh oxygen and hydrogen.

[insert_name]

looks like ARCA is still around and is now building an eco rocket heavy that looks like someone tried to save funds in career mode by skipping the unlock for vertical decouplers, and financed by some sort of crypto scheme. https://www.amiexploration.com/_files/ugd/b4b6cb_0e96270b6f1f4828ba51284ca4e15860.pdf

[RCgothic]

And apparently a Scott Manley video mocking their idea put off a lot of investors.

 

Yeah, this thing isn't ever launching. I mean look at it, is ridiculous. I can't believe they looked at starship dev and thought "You know what we need less of? Tall cranes."

[insert_name]

1 hour ago, RCgothic said:

And apparently a Scott Manley video mocking their idea put off a lot of investors.

 

Yeah, this thing isn't ever launching. I mean look at it, is ridiculous. I can't believe they looked at starship dev and thought "You know what we need less of? Tall cranes."

they only gave that video a footnote but for some reason decided to spend a page and a half picking apart a Tim Dodd video

[farmerben]

Is this the same company that tried to develop an aerospike and only defrauded investors?

 

[insert_name]

24 minutes ago, farmerben said:

Is this the same company that tried to develop an aerospike and only defrauded investors?

 

The CEO was indicted and arrested for securities fraud, but was acquitted and then deported, the report in my recent post has a half page footnote blaming a conspiracy involving a disgruntled investor, DHS, the Government of New Mexico and his ex-wife. 

[Flying dutchman]

Ridiculous design. It has been tried before and it didn't pan out. I believe there is a Scott Manley video about this. The company thought that making a very simple pressure fed rocket stage and bolting as many as needed together was a good idea.

 

Edit:

 

It was the otrec (or otrac) rocket system.

 

 

4:10

 

Edited July 21, 2022 by Flying dutchman

[RCgothic]

I suppose an overgrown bottle rocket counts as pressure fed. There's no ignition at all and the ISP is absolute junk.

[DDE]

I've checked up on ARCA very recently, and this new development is... a rather unpleasant surprise. They just keep jumping on bandwagons; OTRAG is just the latest one.

[sevenperforce]

6 hours ago, Flying dutchman said:

Ridiculous design. It has been tried before and it didn't pan out. I believe there is a Scott Manley video about this. The company thought that making a very simple pressure fed rocket stage and bolting as many as needed together was a good idea.

Edit:

It was the otrec (or otrac) rocket system.

At least OTRAG would have worked.

This is nonsense.

[wumpus]

Sure that name isn't Acme?  With one Wile E. Coyote as test pilot?

Anybody know the Isp of the pressurized air/water combination you had from air pumped toy rockets that were popular in the 1970s?  Probably pretty close, especially in terms of "getting to space".

This isn't to say that "steam" isn't a good idea, as long as you use hydrogen instead of water (water shows they are clearly optimizing the wrong thing, presumably the better to con investors).  NTR uses superheated hydrogen to get amazing Isp (although don't expect to get the TWR to launch from Earth).  Launching from Earth may be possible by using lasers to continually heat the "fuel tank" as it loses pressure by providing thrust.  On company that went out of business trying to get money for the R&D was called "Escape Dynamics".  My guess is the idea is to let the military develop the lasers, and then somehow obtain the tech.

[Flying dutchman]

20 hours ago, sevenperforce said:

At least OTRAG would have worked.

This is nonsense.

If it was not clear yet... My opinion of Arca is not positive and I do not think their concept will work and is stupid.

Edited July 22, 2022 by Flying dutchman

[kerbiloid]

The overheated water steam tends to turn into effective hydrolox fuel.

Spoiler

 

[sevenperforce]

2 hours ago, Flying dutchman said:

If it was not clear yet... My opinion of Arca is not positive and I do not think their concept will work and is stupid.

Oh yes I could tell. 

1 hour ago, kerbiloid said:

The overheated water steam tends to turn into effective hydrolox fuel.

  Reveal hidden contents

 

Too soon?

[kerbiloid]

1 hour ago, sevenperforce said:

Too soon?

Back to the Future.

[tomf]

Spoiler

Spoiler

 

 

https://what-if.xkcd.com/24

That design is what you get when your ISP isn't really good enough

Edited July 22, 2022 by tomf

[RCgothic]

Which is why they have to cheat and use RP1/Hydrogen Peroxide for the upper stage.

[kerbiloid]

In case if the lower stage didn't explode.

[sevenperforce]

Apparently they have dusted off their inanity and are now trying to launch a rocket out of a water tower?

 

[tater]

10 minutes ago, sevenperforce said:

Apparently they have dusted off their inanity and are now trying to launch a rocket out of a water tower?

The secret sauce is that it is powered by crypto! You give arca crypto, they put it in their rocket, and it comes out as exhaust, simultaneously doubling your crypto!

[Shpaget]

Mini Sea Dragon. Just add water!*

*Salt to taste.