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ARCA Expendable Smallsat SSTO

sevenperforce

By sevenperforce
in Science & Spaceflight

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KSK

KSK

Posted
Posted (edited)
On ‎04‎/‎04‎/‎2017 at 6:40 PM, Shpaget said:

Of course. But one could make the same connection about rockets that have engines. As a matter of fact, every single rocket that failed during the launch had at least one engine. :0.0:

In most cases, the operative word was 'had'.

Edit. Sorry - replying to old post. Please disregard or delete if a friendly moderator is passing by.

Edited by KSK
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sevenperforce

sevenperforce

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Popescu looks like he just found out his girlfriend has been cheating on him with Arnold Schwarzenegger.

The shot of the aerospike on the test stand is Photoshop.

The "Helen Engine" test from freaking 2009 is their HTP monoprop test. Really nothing to do with this. I mean, yes, they're using HTP+kerosene, which is a time-honored bipropellant combo (I still love the hell out of Black Arrow) but the aerospike is a different beast.

Is it possible to use HTP decomposition for self-pressurization? I think it ought to be possible. Haven't figured out a way to make it work yet, though.

30 minutes ago, NSEP said:

Wait, didn't they ditch the Aerospike?

No, that was Firefly. They ditched their toroidal single-chamber aerospike. ARCA has always had a linear aerospike. Which, FWIW, is probably the way to go. A multichamber linear aerospike gives you pitch, yaw, and roll using nothing but differential thrust, and you can do it pressure-fed.

I've said it before and I'll say it again -- the smallest possible reusable launch vehicle is a parallel-staged linear aerospike packing self-pressurizing keroxide, with chuted recovery. It's the only prop combo that can beat out solids in impulse density while still maintaining enough Isp to put something useful into LEO-300 m/s.

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wumpus

wumpus

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15 hours ago, sevenperforce said:

I've said it before and I'll say it again -- the smallest possible reusable launch vehicle is a parallel-staged linear aerospike packing self-pressurizing keroxide, with chuted recovery. It's the only prop combo that can beat out solids in impulse density while still maintaining enough Isp to put something useful into LEO-300 m/s.

The only successful uses of chuted recovery have been:

huge steel tubes hitting the water 23 m/s (50mph).
capsule return
film return from spy satellites (snatched by aircraft in the US, not sure how the USSR did it)
at least one civilian unmanned spacecraft snatched in the air

I don't think Spacex got anywhere with parachutes and Falcon 1 (which presumably was a major design goal).  Assuming "parallel staged" implies snatching *two* "first stages" out of the air, I can't imagine getting FAA permission to do such a thing (military organizations might get away with it).

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sevenperforce

sevenperforce

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1 hour ago, wumpus said:

The only successful uses of chuted recovery have been:

huge steel tubes hitting the water 23 m/s (50mph).
capsule return
film return from spy satellites (snatched by aircraft in the US, not sure how the USSR did it)
at least one civilian unmanned spacecraft snatched in the air

I don't think Spacex got anywhere with parachutes and Falcon 1 (which presumably was a major design goal).  Assuming "parallel staged" implies snatching *two* "first stages" out of the air, I can't imagine getting FAA permission to do such a thing (military organizations might get away with it).

Size is a big deal. High-diameter, low-wall-thickness tubes like a Falcon 9 (or even a Falcon 1) have a really poor bending moment, especially when they are constructed from metal.

The STS SRBs could survive hitting the water because they were hella strong in the first place, being the combustion chamber and all.

A composite rocket stage smaller than a Falcon 1, with very dense propellants allowing small tank size, would have a pretty decent shot of surviving chuted splashdown. Especially packing a sturdy aerospike rather than a flimsy de Laval.

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DAL59

DAL59

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11 hours ago, Nuke said:

so its a big dumb booster that manages to simplify a lot of the systems. i like it. 

They built it with easily available tools and parts, and arduinos, and 40 people.  

Yet Blue Origin is behind them in orbital rocket building...

https://youtu.be/MtntTvuv8Aw

 

 

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insert_name

insert_name

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7 hours ago, DAL59 said:

They built it with easily available tools and parts, and arduinos, and 40 people.  

Yet Blue Origin is behind them in orbital rocket building...

https://youtu.be/MtntTvuv8Aw

 

 

The only thing ARCA is ahead of BO in is fraud charges. BO is testing their engine, ARCA hasn't developed theirs yet. I expect the rocket model that we saw in the video to be different from the actual booster as they  will need to accommodate any changes to the engines.

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DAL59

DAL59

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32 minutes ago, tater said:

This is absurd.

 

51 minutes ago, insert_name said:

The only thing ARCA is ahead of BO in is fraud charges. BO is testing their engine, ARCA hasn't developed theirs yet. I expect the rocket model that we saw in the video to be different from the actual booster as they  will need to accommodate any changes to the engines.

I know.  The rockets are completly different, and I'm sort of joking.  But there is a good chance they'll manage to reach orbit before BO.

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tater

tater

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14 minutes ago, DAL59 said:

 

I know.  The rockets are completly different, and I'm sort of joking.  But there is a good chance they'll manage to reach orbit before BO.

Nonsense.

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Wjolcz

Wjolcz

Posted
Posted (edited)
On 5/11/2018 at 4:30 AM, insert_name said:

I expect the rocket model that we saw in the video to be different from the actual booster as they  will need to accommodate any changes to the engines.

AFAIK aerospikes are easier to stack than regular nozzles. What was showed in the video looked like just a part of the engine. If that thing works they will probably just stack a couple of these side by side and it should be ready to go.

On 5/11/2018 at 5:23 AM, DAL59 said:

But there is a good chance they'll manage to reach orbit before BO.

I will be very surprised when that happens.

That being said, I'm not sure what to think about it. I will be pleasantly surprised if they develop the aerospike, actually fly it and stay around long enough to launch a commercial payload. SpaceX managed to land a bunch of boosters, bring the prices down and force other companies to seriously think about building and flying rockets cheaper by recovering them. It's 21st century and anything can happen.

EDIT: OH WHAT THE HELL IS THIS

 

NEVERMIND, IT'S GOING TO BE THE ZEN EGG OF ROCKETS

Edited by Wjolcz
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DAL59

DAL59

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54 minutes ago, Wjolcz said:

AFAIK aerospikes are easier to stack than regular nozzles. What was showed in the video looked like just a part of the engine. If that thing works they will probably just stack a couple of these side by side and it should be ready to go.

I will be very surprised when that happens.

That being said, I'm not sure what to think about it. I will be pleasantly surprised if they develop the aerospike, actually fly it and stay around long enough to launch a commercial payload. SpaceX managed to land a bunch of boosters, bring the prices down and force other companies to seriously think about building and flying rockets cheaper by recovering them. It's 21st century and anything can happen.

EDIT: OH WHAT THE HELL IS THIS

 

NEVERMIND, IT'S GOING TO BE THE ZEN EGG OF ROCKETS

Couldn't you build a better one yourself for far less money?  That's a horrible design. 

And a horrible, overhyped video.   

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