ARCA

[Humuku]

Why has the second stage fins? Why use fins on the first stage?

[Steven Pietrobon]

Why has the second stage fins? Why use fins on the first stage?

Due to its very short flight, the first stage separates well within the atmosphere at about 3 km altitude. I'm guessing the fins on the second stage provide stability during separation and second stage flight.

The fins on the first stage serve two purposes. Provide stability during flight and serve as the landing legs.

[Steven Pietrobon]

Also, pardon my ignorance of aerospike technology, but isn't there supposed to be a ring of combustion chambers (or in the case of ARCA technology, garden hoses) around the outside, aiming towards the spike, with the idea being that the flow is contained on one side by the spike and on the other side by atmospheric pressure? In the pictures ARCA showed above, I don't see anywhere for the boiling water to pour out. Unless that black shadowed area is basically a slit, and the water just comes out through there? Still doesn't seem like that would do much to direct the water stream inwards, towards the spike.

Yes, there looks to be a very small gap between the nozzle and the outer wall where the steam is exhausted. See the prototype engine below.

https://arcaspace.com/en/LAS.htm

[Fmedici]

https://twitter.com/arcaspace/status/1409538133721505795

[Beratnyi]

Thanks to yesterday's presentation, new data on the mass of the EcoRocket stages appeared. The dry mass of the stages is 452 kg, the total mass of the rocket is 4930 kg, with a maximum payload of 10 kg it will be 4940 kg. Stage 1 - dry weight 360 kg, gross weight 3930, calculation of delta-v at 80 sec isp and 70 kg of landing fuel is equal to 967.11 m / s; Stage 2 - dry weight 80 kg, gross weight 830 kg, calculation of delta-v at 90 sec isp (work in the upper atmosphere) is equal to 1197.71 m / s; Stage 3 - dry weight 12 kg, gross weight 170 kg, calculation of delta-v at 320 sec isp is 6596.08 m / s. The delta-v of the entire rocket is 8760.9 m / s. If we take into account the low gravitational losses due to the high thrust to the weight of the stages, this will be quite enough to deliver 10 kg of cargo to low-earth orbit.

[Toast]

Why has the second stage fins? Why use fins on the first stage?

Due to its very short flight, the first stage separates well within the atmosphere at about 3 km altitude. I'm guessing the fins on the second stage provide stability during separation and second stage flight.

The fins on the first stage serve two purposes. Provide stability during flight and serve as the landing legs.

I propose a far simpler reason: Because they thought the fins looked cool. Given ARCA's history, I doubt much more thought than that went into it.

[TorenAltair]

Oh come on please. Every new info about ARCA is followed by several posts about how much scam that all is. I don't see the same thing on a lot of other companies which so far have the same or less to show. Can we please stick to the facts without mocking, blaming etc?

[Jim]

Oh come on please. Every new info about ARCA is followed by several posts about how much scam that all is. I don't see the same thing on a lot of other companies which so far have the same or less to show. Can we please stick to the facts without mocking, blaming etc?

The facts are that it is a scam

[Toast]

Oh come on please. Every new info about ARCA is followed by several posts about how much scam that all is. I don't see the same thing on a lot of other companies which so far have the same or less to show. Can we please stick to the facts without mocking, blaming etc?

I think this forum is pretty well-calibrated in that regard. You don't see people accusing ULA, SpaceX, or Blue of being scams. When companies are clearly over promising (e.g. Vector), they are met here with well-warranted skepticism. And when they're very obviously a scam (like ARCA), they're treated as such.

But hey, I'm willing to put my money where my mouth is. I'd be more than willing to wager that no ARCA rocket will ever make orbit. Open-ended bet, no expiration date. If ARCA ever successfully launches a rocket to orbit, I'll buy TorenAltair a year's subscription to L2 or an equivalent value of swag from the NSF shop. No need to match my wager, if ARCA goes broke or their CEO finally gets indicted for fraud I'll just buy myself the L2 subscription and post a smug told-you-so.

[RoadWithoutEnd]

"ARCA".  I remember this name from the old days.  But it never claimed to have a lot of resources.  If it hasn't gotten anywhere, are we supposed to blame it while Blue Origin has failed to get to orbit in twenty years?

Stay neutral, is my thought.  Stranger things have happened than a company like that getting somewhere late.

Long as they're not taking deposits, they're better than Virgin Galactic was.

[meekGee]

Oh come on please. Every new info about ARCA is followed by several posts about how much scam that all is. I don't see the same thing on a lot of other companies which so far have the same or less to show. Can we please stick to the facts without mocking, blaming etc?

I think this forum is pretty well-calibrated in that regard. You don't see people accusing ULA, SpaceX, or Blue of being scams. When companies are clearly over promising (e.g. Vector), they are met here with well-warranted skepticism. And when they're very obviously a scam (like ARCA), they're treated as such.

But hey, I'm willing to put my money where my mouth is. I'd be more than willing to wager that no ARCA rocket will never make orbit. Open-ended bet, no expiration date. If ARCA ever successfully launches a rocket to orbit, I'll buy TorenAltair a year's subscription to L2 or an equivalent value of swag from the NSF shop. No need to match my wager, if ARCA goes broke or their CEO finally gets indicted for fraud I'll just buy myself the L2 subscription and post a smug told-you-so.

Oh plenty people called SpaceX a scam.

Turns out, what you call it doesn't affect what it is.

I'm giving ARCA the moral benefit of the doubt that it is self-delusional rather than a cynical scam.

[Beratnyi]

Thanks to yesterday's presentation, new data on the mass of the EcoRocket stages appeared. The dry mass of the stages is 452 kg, the total mass of the rocket is 4930 kg, with a maximum payload of 10 kg it will be 4940 kg. Stage 1 - dry weight 360 kg, gross weight 3930, calculation of delta-v at 80 sec isp and 70 kg of landing fuel is equal to 967.11 m / s; Stage 2 - dry weight 80 kg, gross weight 830 kg, calculation of delta-v at 90 sec isp (work in the upper atmosphere) is equal to 1197.71 m / s; Stage 3 - dry weight 12 kg, gross weight 170 kg, calculation of delta-v at 320 sec isp is 6596.08 m / s. The delta-v of the entire rocket is 8760.9 m / s. If we take into account the low gravitational losses due to the high thrust to the weight of the stages, this will be quite enough to deliver 10 kg of cargo to low-earth orbit.

[niwax]

Oh come on please. Every new info about ARCA is followed by several posts about how much scam that all is. I don't see the same thing on a lot of other companies which so far have the same or less to show. Can we please stick to the facts without mocking, blaming etc?

I think this forum is pretty well-calibrated in that regard. You don't see people accusing ULA, SpaceX, or Blue of being scams. When companies are clearly over promising (e.g. Vector), they are met here with well-warranted skepticism. And when they're very obviously a scam (like ARCA), they're treated as such.

But hey, I'm willing to put my money where my mouth is. I'd be more than willing to wager that no ARCA rocket will never make orbit. Open-ended bet, no expiration date. If ARCA ever successfully launches a rocket to orbit, I'll buy TorenAltair a year's subscription to L2 or an equivalent value of swag from the NSF shop. No need to match my wager, if ARCA goes broke or their CEO finally gets indicted for fraud I'll just buy myself the L2 subscription and post a smug told-you-so.

I'd move ARCA slightly further from scam and Vector a lot closer since they don't appear to be taking investment money using those false promises, and they're certainly not sponsoring their racing hobby.

Not that they're any more credible. But at this precise moment in time they don't appear to be scamming anyone.

[PM3]

Racheta EcoRocket realizată în România va fi lansată de pe mare în luna august

(The EcoRocket rocket made in Romania will be launched from the sea in August)

[ncb1397]

EcoRocket episode 10:

[JCRM]

Mission 10? Have I missed 9 launches?

The Wikipedia has a list of ARCAspace missions, although between it being somewhat out of order (why is Mission 8 before Mission 7?), the wide range of vehicles being nominally tested, some missions being un-numbered, and some missions (7 and 9) seemingly skipped altogether...well, it's what one should expect from ARCAspace.

And NASA?

[billh]

ARCA's been out there so long I may be forgetting some evidence of actual fraud, but I wouldn't say they're a scam. The X Prize attracted a bunch of people I would call "dreamers" and I put ARCA in that category. Interorbital is still around, and maybe Starchaser, but most of the rest are gone. There was the daVinci Project, Canadian Arrow, and others. They all have a similar story: a visionary leader who is not a professional aerospace engineer but has dreamed of going to space since childhood. They attract a number of like-minded people to help, and scrounge donations wherever they can. But it's always a shoestring budget and a dream. They rarely launch anything because, to be frank, they don't have the funds to build anything that could actually fly.

It took the arrival of the tech billionaires to really get anywhere in private space flight: Paul Allen, Elon Musk and Jeff Bezos. It just turns out that it takes more money than even the Vector guys were able to raise. And they had more than most. Garvey has actually built a lot of rockets but generally in the high end model rocketry range. Getting to orbit requires big, high powered rockets, staging, telemetry, guidance, etc. It's just too hard for a bunch of enthusiasts to pull off. It takes real money and real skills.

[Steven Pietrobon]

Here's the photo from the tweet and being loaded onto the ship.

I see they are using 95% HTP for the third stage. Black Knight and Black Arrow used 85%.

[daedalus1]

What's eco (ecological?) about it?

[STS-200]

What's eco (ecological?) about it?

It won't be polluting Earth orbit by launching any satellites into it ...