Author Topic: ARCA Space Corporation  (Read 18182 times)

Online Davidthefat

ARCA Space Corporation
« on: 10/19/2015 11:48 PM »
ARCA Space Corporation has recently moved its headquarters to Las Cruces, New Mexico and has announced a partnership with Spaceport America, where it will launch and test its vehicles.

Has anyone heard of this company in the past? I've done some looking around and they seem to have chosen some interesting design choices regarding their launch vehicles. The biggest one being that the LES for the Haas 2B being incorporated into the second stage instead of the spacecraft.

http://www.arcaspace.com/index.htm

http://spaceportamerica.com/press-release/spaceport-america-and-arca-space-corporation-announce-partnership-for-space-launch-vehicle-and-high-altitude-autonomous-aircraft-testing/
« Last Edit: 10/20/2015 05:07 AM by Davidthefat »

Offline WmThomas

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Re: ARCA Aerospace Corporation
« Reply #1 on: 10/20/2015 12:21 AM »
As they note on their new website, they are the Romanian group that tried to compete in the Ansari X prize and have continued to work on aerospace projects.

I don't think there is much chance they will become a reliable commercial enterprise providing some regular service. They've been more a one-shot focus organization.

But what brought about the move to the US? Or is it just a move in legal domicile, kind of like Rocketlab?

Online Davidthefat

Re: ARCA Aerospace Corporation
« Reply #2 on: 10/20/2015 12:42 AM »
But what brought about the move to the US? Or is it just a move in legal domicile, kind of like Rocketlab?

Quote
“Only in New Mexico did we find the perfect combination of aerospace assets, airspace and affordability,” emphasized Dumitru Popescu, Founder and CEO of ARCA Space Corporation. “Proximity to Spaceport America and the expansive access to airspace were crucial factors in our decision to locate our global headquarters to Las Cruces, New Mexico in the United States.”

I presume the recent tax cuts (5.9%) in New Mexico (http://archive.lcsun-news.com/las_cruces-news/ci_22951305/gov-susana-martinez-signs-bill-lowering-nm-corporate) and the combination of Spaceport America critically in need of clients. And there are deduction available for space companies (http://gonm.biz/why-new-mexico/competitive-business-climate/incentives/space-gross-receipts-tax-deductions)
« Last Edit: 10/20/2015 12:46 AM by Davidthefat »

Online BrianNH

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Re: ARCA Space Corporation
« Reply #3 on: 10/20/2015 12:03 PM »
Quote
The Accelerator is available for pre-order and will enter into production in May 2015.

Quote
The Interface is available for pre-order and will enter into production in May 2015

These are both still on pre-order.

Offline TrevorMonty

Re: ARCA Space Corporation
« Reply #4 on: 10/21/2015 04:33 AM »
Thanks David for information. Another interesting company to watch. If they start flying and selling their drones in 2016 (as per website), then cashflow maybe there to build their LVs.

Offline Gliderflyer

Re: ARCA Space Corporation
« Reply #5 on: 03/29/2017 04:09 AM »
Well, this could be interesting. It looks like ARCA might be returning to rockets. From Facebook:
Quote
Starting tomorrow, ARCA Space Corporation is going to unveil more information about this space vehicle.
They included a picture (attached) of what appears to be a mockup vehicle with a linear aerospike. It looks similar in size to their SSTO concept from a few years ago: https://en.wikipedia.org/wiki/Haas_(rocket)#Haas_2c
I tried it at home

Online Davidthefat

Re: ARCA Space Corporation
« Reply #6 on: 03/29/2017 04:34 PM »
Well, this could be interesting. It looks like ARCA might be returning to rockets. From Facebook:
Quote
Starting tomorrow, ARCA Space Corporation is going to unveil more information about this space vehicle.
They included a picture (attached) of what appears to be a mockup vehicle with a linear aerospike. It looks similar in size to their SSTO concept from a few years ago: https://en.wikipedia.org/wiki/Haas_(rocket)#Haas_2c

This company seems to pivot way too many times, from rockets to drones, hoverboards, some kind of motorized skates, back to rockets again...


Updated their website...
I don't think their math checks out.
http://www.arcaspace.com/en/haas2c.htm
« Last Edit: 03/29/2017 09:33 PM by Davidthefat »

Offline Gliderflyer

Re: ARCA Space Corporation
« Reply #7 on: 03/30/2017 03:57 AM »
Updated their website...
I don't think their math checks out.
http://www.arcaspace.com/en/haas2c.htm

Yeah, hitting that mass ratio of 29 is going to be fun. They have a video up too:
 

 
To summarize: it is an all composite pressure fed peroxide/kerosene SSTO small sat launcher powered by a differentially throttled linear aerospike, with a first flight from Wallops in 2018. Given their past performance, I will remain skeptical.
I tried it at home

Online Steven Pietrobon

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Re: ARCA Space Corporation
« Reply #8 on: 03/30/2017 08:49 AM »
Cool! They are using liquid Helium, heated in the engine to make gaseous Helium to pressurise the tanks. This is what SpaceX should be doing. For SSTO though, my research indicates using LOX/RP-1 gives better performance than HTP/RP-1.
« Last Edit: 03/30/2017 08:52 AM by Steven Pietrobon »
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Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #9 on: 03/30/2017 01:48 PM »
I would love to see a linear aero spike fly, but that and all carbon construction with no attempt at reuse seems like it would end up being much more expensive than a million dollars a launch.

Offline JH

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Re: ARCA Space Corporation
« Reply #10 on: 03/30/2017 03:25 PM »
Yeah, seeing an aerospike fly would be cool. The fact that they have the thing going in to dock with the ISS at the end of the video makes me even more skeptical that I would be otherwise, though.

Offline rompecabezas

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Re: ARCA Space Corporation
« Reply #11 on: 03/31/2017 06:24 PM »
I just want em to develop the linear aerospike, i think it could be a good start for a SSTO spaceplane.

Compared to a common engine, it has better performance in terms of thrust to weight ratio?

Offline ringsider

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Re: ARCA Space Corporation
« Reply #12 on: 03/31/2017 06:40 PM »
How many companies doing paper rockets now?

Offline TrevorMonty

Re: ARCA Space Corporation
« Reply #13 on: 03/31/2017 09:21 PM »
It's not as high risk as it looks. This aerospike design has been proven on ground by NASA. Most of smallsat launchers are going with carbon fibre tanks. Small 3d printed pressure fed engines are far from leading edge technology, even university students build them.

If flys but doesn't quite deliver performance expected, they will still have a high performance booster to add a 2nd stage to.
« Last Edit: 03/31/2017 09:25 PM by TrevorMonty »

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #14 on: 03/31/2017 09:52 PM »
I've been watching ARCA since the X-Prize days.  Even by the standards of start-up space companies, ARCA has been particularly bad about wild claims that never led anywhere.

For a while, ARCA was showing designs for their "Stabilo" launcher that they claimed was stabilized by having the rocket nozzles up front, showing they didn't even understand the elementary principle of the rocket pendulum fallacy.  The same fallacy tripped up Goddard in his early days, but in the modern world there's no excuse for someone who claims to know something about rockets not to know that.

They're in a league with Excalibur Almaz and only slightly better than JP Aerospace in terms of lack of credibility.  I'd believe more in a high-school drop-out deciding to start a launch company, because at least that person wouldn't have a history of extravagant claims with nothing to back them up.

Online Davidthefat

Re: ARCA Space Corporation
« Reply #15 on: 03/31/2017 09:56 PM »
It's not as high risk as it looks. This aerospike design has been proven on ground by NASA. Most of smallsat launchers are going with carbon fibre tanks. Small 3d printed pressure fed engines are far from leading edge technology, even university students build them.

If flys but doesn't quite deliver performance expected, they will still have a high performance booster to add a 2nd stage to.

Brought to you by a company whose latest products were an over glorified multicopter "hover board" with a 5 minute flight time and a motorized skateboard/rover thing (not to mention, they took out all references to it on their site)?

http://www.theverge.com/2016/6/24/12023744/arca-space-electric-skateboard-arcaboard-hoverboard-mini

Not much confidence in their success.

Offline TrevorMonty

Re: ARCA Space Corporation
« Reply #16 on: 03/31/2017 11:12 PM »
I'm not giving company any credibility, I'd be surprise if they fly anything.

Their LV design is with in current technology levels.

Offline Bob Shaw

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Re: ARCA Space Corporation
« Reply #17 on: 03/31/2017 11:36 PM »
They're in a league with Excalibur Almaz and only slightly better than JP Aerospace in terms of lack of credibility.  I'd believe more in a high-school drop-out deciding to start a launch company, because at least that person wouldn't have a history of extravagant claims with nothing to back them up.


JP Aerospace are, however, both wonderfully Heinlienen and wonderfully off-the-wall - I really enjoy their penny-pinching airship-to-orbit ideas, which are sorta-maybe-possibly possible, even if fuelled by Unobtanium and hand-waving.

Offline Nomadd

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Re: ARCA Space Corporation
« Reply #18 on: 04/01/2017 12:41 AM »
Uh...A 53 foot tall 36,000 pound rocket that weighs 1200 pounds empty?

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #19 on: 04/01/2017 12:51 AM »
These are the same people who claimed in 2012 that they would win the Google Lunar X Prize by launching a space plane that looks a lot like an F-22 from the water and have that carry an upper stage slung underneath that would go to the Moon.  The word "unbelievable" doesn't even begin to cover it.  You have to watch the video to see how stunningly disconnected from reality this group's claims are.



Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #20 on: 04/01/2017 01:48 AM »
That is hilarious. Rutan wants his windows back.

Offline BrightLight

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Re: ARCA Space Corporation
« Reply #21 on: 04/01/2017 05:43 PM »
Remember that it's critical to have a stealth aircraft take off from water to launch a rocket (water proof!) to orbit, Thunderbirds are go

Offline ringsider

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Re: ARCA Space Corporation
« Reply #22 on: 04/01/2017 10:06 PM »
Remember that it's critical to have a stealth aircraft take off from water to launch a rocket (water proof!) to orbit, Thunderbirds are go
I will just drop this here:-

http://www.parabolicarc.com/2016/09/19/norwegian-company-working-ocean-launched-rocket/

Online Welsh Dragon

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Re: ARCA Space Corporation
« Reply #23 on: 04/01/2017 10:31 PM »
Launching from water isn't in itself a problem for a well designed rocket, see Seabee and Seahorse. It's the combination of a stealth seaplane with under-slung rocket that's rather... out there.

Offline ANTIcarrot

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ARCA Haas 2CA (expendable SSTO)
« Reply #24 on: 04/02/2017 02:28 PM »
Reported by Newatlas suspiciously close to April first, but...

ARCA space corporation has a blueprint for an expendable SSTO with a lift off mass of 16.3 tons capable of putting ~50kg into orbit. (For an given definition of orbit presumably.) The design weight would be 510kg empty, and would run on HTP/RP-1 using a linear aerospike. Another version of the rocket would fly with 2 stages and a heavier payload.

Size, weight, cargo, and fuel look oddly similar to the UK Black Arrow, save that was a three stage launcher, and had an empty weight closer to 1.7 tons. Given the Black Arrow was built on a shoe string, in the late 60s, and was possibly over-engineered, there might be some mass savings to be made there, but 1.2 tons?

Carbon fibre woudl produce some weight reduction, as well as building it so it properly crumples on impact rather than just getting slightly dented. Balloon tanks supposedly produce some weight saving, but can't find any actual numbers.

Latter might be worth talking about even if the rest is pie in the sky. Has anyone got any hard numbers for exactly how much savings balloon tanks provide? And has anyone actually tried building a carbon fibre balloon tank? Cryo or otherwise.
« Last Edit: 04/02/2017 02:29 PM by ANTIcarrot »

Offline Asteroza

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Re: ARCA Space Corporation
« Reply #25 on: 04/02/2017 11:32 PM »
Is there even an advantage to a linear aerospike over a toroidal aerospike for a simple cylinder body?

Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #26 on: 04/03/2017 04:06 AM »
This showed up on Youtube after I watched the video linked above.



This all worked out well didn't it?

Matthew

Offline kch

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Re: ARCA Space Corporation
« Reply #27 on: 04/03/2017 04:44 AM »
Is there even an advantage to a linear aerospike over a toroidal aerospike for a simple cylinder body?

Roll control.  :)

Offline savuporo

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Re: ARCA Space Corporation
« Reply #28 on: 04/03/2017 04:51 AM »
Is there even an advantage to a linear aerospike over a toroidal aerospike for a simple cylinder body?

Roll control.  :)

No, the CGI looks better.
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Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #29 on: 04/03/2017 02:46 PM »
Cool! They are using liquid Helium, heated in the engine to make gaseous Helium to pressurise the tanks. This is what SpaceX should be doing. For SSTO though, my research indicates using LOX/RP-1 gives better performance than HTP/RP-1.
SpaceX did use liquid helium heated in an engine heat exchanger to pressurize the tanks for the pressure-fed Kestrel engine. And SpaceX still uses a heat exchanger to increase the helium pressurant efficiency in the Falcon 9 first and second stages, though the heat exchanger is in the Merlin's gas generator rather than in the chamber.

Pressure-fed designs don't typically make sense for large stages, but with a composite tank/body and an aerospike engine, it's not a bad idea. The aerospike engine's high expansion efficiency means a lower chamber pressure (required for pressure-fed designs) is less punishing, and a pressure-fed design saves the mass of a turbopump, which makes up for the aerospike's lower TWR.

True, HTP/RP-1 has lower specific impulse than kerolox, but it's one of the only non-exotic combinations that has higher thrust than kerolox, which is important for the heavy aerospike engine. HTP is also cheaper than LOX, and while it has its own handling challenges, it's less challenging from a materials standpoint than LOX.

So...yeah. If you're going to do an expendable SSTO on the cheap, this isn't a half-bad way to go about it. I could try to throw together some speculative maths on this to get an idea of what sort of mass fraction it would need to hit, based on known engineering.

Whether this company has the capability for anything like this...well, that's another matter entirely.

I could see an SSTO of this type being used in combination with a SEP LEO bus to grapple comsats and toss them into a useful orbit.

Is there even an advantage to a linear aerospike over a toroidal aerospike for a simple cylinder body?

Roll control.  :)
A single-chamber toroidal aerospike has no control authority at all; a multichamber toroidal aerospike has pitch and yaw authority but no roll authority. A multichamber linear aerospike has pitch, yaw, and roll authority with no moving parts, simply by differential throttling. And for a pressure-fed design, that works rather well.

EDIT: For all their whining about the horrors of staging, this particular design could benefit greatly from the optional addition of some strap-on COTS parallel SRBs. For small LEO comsats you could just use the base configuration; for larger payloads you simply charge the customer for adding 2 or 4 SRBs as needed. Much simpler and cheaper than worrying about adding a second stage.
« Last Edit: 04/03/2017 03:36 PM by sevenperforce »

Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #30 on: 04/03/2017 08:47 PM »
Looking for red flags in these specs:

Length: 16 m
Diameter: 1.5 m
Dry mass: 550 kg
Launch mass: 16,290 kg
Payload mass: 100 kg
Engine: Pressure-fed linear aerospike
Nozzle: 80:1 expansion ratio, 80% cut
Engine coolant & pressurant: Liquid helium
Number of chambers: 16
Nozzle cooling: Ablative + RP-1 film
Propellant: HTP + RP-1
Burn duration: 272 s
Thrust (SL): 22,920 kgf
Thrust (vac): 33,500 kgf
Isp (SL): 230 s
Isp (vac): 314 s
Propellant flow rate: 100 kg/s
Mixture ratio: 7.46:1
Tank pressure: 20 barg
Chamber pressure: 16 barg

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #31 on: 04/03/2017 08:56 PM »
Looking for red flags in these specs:

Length: 16 m
Diameter: 1.5 m
Dry mass: 550 kg
Launch mass: 16,290 kg

That dry mass seems awfully optimistic to me.

Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #32 on: 04/03/2017 09:12 PM »
Looking for red flags in these specs:

Length: 16 m
Diameter: 1.5 m
Dry mass: 550 kg
Launch mass: 16,290 kg

That dry mass seems awfully optimistic to me.
Yeah, it does seem optimistic to me as well. That's only 12% more dry mass than the ITS Tanker, which has higher TWR engines, a lower vehicle TWR, and a huge square-cube advantage. Then again, the ITS Tanker also has TPS and RCS systems, which the ARCA rocket wouldn't have to bother with. HTP is also a great deal denser than LOX, so that helps a bit.

Anyone have an idea of ballpack TWR for a pressure-fed linear aerospike?

If ARCA added disposable air augmentation shrouds -- panels, really -- jettisoned at the same time as the payload fairing, they could make up for that horrible SL specific impulse. I bet that mixture ratio optimization could help as well.

« Last Edit: 04/03/2017 09:12 PM by sevenperforce »

Offline GWH

Re: ARCA Space Corporation
« Reply #33 on: 04/03/2017 09:49 PM »
Interesting in that rocket lab chose battery powered pumps over pressure fed due to overall mass savings and even with composite structures.
Given that they are using HTP I wouls have thought decomposition driven turbopumps would be the most efficient solution.

Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #34 on: 04/03/2017 10:55 PM »
Interesting in that rocket lab chose battery powered pumps over pressure fed due to overall mass savings and even with composite structures.
Given that they are using HTP I wouls have thought decomposition driven turbopumps would be the most efficient solution.
Does RL's Electron use composite tanks or aluminum tanks? Composites, as with the ARCA vehicle, work much better with pressure-fed designs than aluminum, so that's one reason.

I'm guessing the increased dry mass of the turbopump alone would be greater than the added mass of the full liquid helium tank. The composite tank can probably handle the pressure without needing to be any thicker than it would otherwise be. HTP has poor enough specific impulse as it is; reducing its efficiency by decomposition would make it even worse.

Offline GWH

Re: ARCA Space Corporation
« Reply #35 on: 04/03/2017 11:03 PM »
Interesting in that rocket lab chose battery powered pumps over pressure fed due to overall mass savings and even with composite structures.
Given that they are using HTP I wouls have thought decomposition driven turbopumps would be the most efficient solution.
Does RL's Electron use composite tanks or aluminum tanks? Composites, as with the ARCA vehicle, work much better with pressure-fed designs than aluminum, so that's one reason.

I'm guessing the increased dry mass of the turbopump alone would be greater than the added mass of the full liquid helium tank. The composite tank can probably handle the pressure without needing to be any thicker than it would otherwise be. HTP has poor enough specific impulse as it is; reducing its efficiency by decomposition would make it even worse.

Electron is composite construction.  Somewhere in discussion on the vehicle some one calculated mass of the vehicle with required wall thickness for pressure fed vs without and found that even with the added mass of batteries it was a much more mass efficient option.

Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #36 on: 04/03/2017 11:21 PM »
Hmm. They are about the same size. The ARCA vehicle is a bit smaller but significantly heavier -- due to the HTP replacing the less dense LOX -- so it has more to lose in the engine dry mass department than Electron.

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #37 on: 04/04/2017 06:18 AM »
Well, Electron also isn't SSTO, so it has far more margin to play with.

Offline savuporo

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Re: ARCA Space Corporation
« Reply #38 on: 04/04/2017 06:23 AM »
Well, Electron also isn't SSTO, so it has far more margin to play with.

It also exists, which constrains it to laws of physics
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Online Steven Pietrobon

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Re: ARCA Space Corporation
« Reply #39 on: 04/04/2017 07:02 AM »
HTP is also cheaper than LOX, and while it has its own handling challenges, it's less challenging from a materials standpoint than LOX.

I'm pretty sure rocket grade HTP is more expensive than LOX. 85% HTP costs $8.27/kg in a 30 kg lot, although should come down for higher volumes. Google says that LOX is $0.16/kg.

http://www.peroxidepropulsion.com/hydrogen-peroxide.php

With a propellant mass of 15,640 kg and a mixture ratio of 8.2 to 1 (the same as the British Gamma engine), that gives a HTP mass of 13,940 kg and a upper bound of the cost of $115,284.
« Last Edit: 04/04/2017 07:02 AM by Steven Pietrobon »
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Offline sevenperforce

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Re: ARCA Space Corporation
« Reply #40 on: 04/04/2017 12:30 PM »
HTP is also cheaper than LOX, and while it has its own handling challenges, it's less challenging from a materials standpoint than LOX.

I'm pretty sure rocket grade HTP is more expensive than LOX. 85% HTP costs $8.27/kg in a 30 kg lot, although should come down for higher volumes. Google says that LOX is $0.16/kg.

http://www.peroxidepropulsion.com/hydrogen-peroxide.php

With a propellant mass of 15,640 kg and a mixture ratio of 8.2 to 1 (the same as the British Gamma engine), that gives a HTP mass of 13,940 kg and a upper bound of the cost of $115,284.
Well, color me surprised.

Well, Electron also isn't SSTO, so it has far more margin to play with.
A fair point. Taking the dry mass of nine battery packs and pumps all the way to orbit probably would have tanked the efficiency advantage.

Plus, doesn't the electron need helium pressurant anyway to maintain ullage pressure?

Online Davidthefat

Re: ARCA Space Corporation
« Reply #41 on: 04/05/2017 10:34 PM »
Their latest "plan" to use tanks as habitats once in orbit...

https://www.facebook.com/arcaspace/photos/a.225583008331.177238.225552438331/10155952223343332/?type=1&theater

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Offline Gliderflyer

Re: ARCA Space Corporation
« Reply #42 on: 04/06/2017 01:11 AM »
Their latest "plan" to use tanks as habitats once in orbit...

https://www.facebook.com/arcaspace/photos/a.225583008331.177238.225552438331/10155952223343332/?type=1&theater

Uploaded screen shot for prosperity
While I am a fan of wet workshops, this is laughable. Those tanks are only ~5 feet in diameter. As depicted, I doubt a person could even fit through the docking port.
I tried it at home

Offline GWH

Re: ARCA Space Corporation
« Reply #43 on: 04/06/2017 01:58 PM »
Quote from: sevenperforce
A fair point. Taking the dry mass of nine battery packs and pumps all the way to orbit probably would have tanked the efficiency advantage.

Plus, doesn't the electron need helium pressurant anyway to maintain ullage pressure?

The whole trade is based on the increased mass required for thicker tank walls for all the propellant at a higher pressure,  not just a couple helium bottles. That mass is going to orbit in either scenario.

Offline josespeck

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Re: ARCA Space Corporation
« Reply #44 on: 04/08/2017 04:12 PM »
Quote from: sevenperforce
A fair point. Taking the dry mass of nine battery packs and pumps all the way to orbit probably would have tanked the efficiency advantage.

Plus, doesn't the electron need helium pressurant anyway to maintain ullage pressure?

The whole trade is based on the increased mass required for thicker tank walls for all the propellant at a higher pressure,  not just a couple helium bottles. That mass is going to orbit in either scenario.

What is the equation for tank thickness?.
What is the thickness of the Falcon9 tank and other?.

Offline Katana

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Re: ARCA Space Corporation
« Reply #45 on: 04/09/2017 03:03 AM »
Looking for red flags in these specs:

Length: 16 m
Diameter: 1.5 m
Dry mass: 550 kg
Launch mass: 16,290 kg
Payload mass: 100 kg
Engine: Pressure-fed linear aerospike
Nozzle: 80:1 expansion ratio, 80% cut
Engine coolant & pressurant: Liquid helium
Number of chambers: 16
Nozzle cooling: Ablative + RP-1 film
Propellant: HTP + RP-1
Burn duration: 272 s
Thrust (SL): 22,920 kgf
Thrust (vac): 33,500 kgf
Isp (SL): 230 s
Isp (vac): 314 s
Propellant flow rate: 100 kg/s
Mixture ratio: 7.46:1
Tank pressure: 20 barg
Chamber pressure: 16 barg

Gas generator pump fed , not pressure fed.
https://en.m.wikipedia.org/wiki/Executor_(rocket_engine)

Offline catdlr

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Re: ARCA Space Corporation
« Reply #46 on: 04/10/2017 04:55 PM »
This one-of-a-kind rocket is designed to reach space in just 5 minutes

Tech Insider

Published on Apr 10, 2017
This rocket is about to change space travel. The Haas 2CA rocket is designed by the ARCA Space Corporation. It's set to be the cheapest rocket of its kind and could get to space faster and cheaper than similar rockets, today.

https://www.youtube.com/watch?v=hcjXvjYRLRE?t=001

Tony De La Rosa

Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #47 on: 04/10/2017 05:19 PM »
This seems to be a CG illustration of a linear aerospike on a pallet jack?

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #48 on: 04/10/2017 06:05 PM »
This one-of-a-kind rocket is designed to reach space in just 5 minutes

Tech Insider

Published on Apr 10, 2017
This rocket is about to change space travel. The Haas 2CA rocket is designed by the ARCA Space Corporation. It's set to be the cheapest rocket of its kind and could get to space faster and cheaper than similar rockets, today.

Wow, Tech Insider just believed all the fantasy ARCA claimed without any attempt to verify any of it or get opinions from outside experts.  Sad.  They present themselves as journalists, but clearly there's no journalism going on here.

The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.

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Re: ARCA Space Corporation
« Reply #49 on: 04/10/2017 07:17 PM »
Bit disingenuous to use footage of XRS-2200 when talking about their engine. Anyone would think they've testfired it already.

Offline ringsider

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Re: ARCA Space Corporation
« Reply #50 on: 04/10/2017 08:20 PM »
This one-of-a-kind rocket is designed to reach space in just 5 minutes

Tech Insider

Published on Apr 10, 2017
This rocket is about to change space travel. The Haas 2CA rocket is designed by the ARCA Space Corporation. It's set to be the cheapest rocket of its kind and could get to space faster and cheaper than similar rockets, today.

Wow, Tech Insider just believed all the fantasy ARCA claimed without any attempt to verify any of it or get opinions from outside experts.  Sad.  They present themselves as journalists, but clearly there's no journalism going on here.

The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.
This is why PR like this and the stories put out by Vector are so insidious. Now any serious company will be held to this "benchmark" by less well-informed investors, making genuine technology look worse.

These people hurt themselves and everybody else.

Online Steven Pietrobon

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Re: ARCA Space Corporation
« Reply #51 on: 04/11/2017 07:18 AM »
The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.

It helps a lot, since gravity losses are reduced, meaning less delta-V is required to reach orbit.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline as58

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Re: ARCA Space Corporation
« Reply #52 on: 04/11/2017 01:48 PM »
I'm starting to think that ARCA is actually a video/CGI production company that likes to advertise by making videos of fanciful rockets.

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Re: ARCA Space Corporation
« Reply #53 on: 04/11/2017 02:26 PM »
The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.

It helps a lot, since gravity losses are reduced, meaning less delta-V is required to reach orbit.

The higher acceleration needed to reach orbit faster is apparently just due to the higher thrust of a SSTO, which has a TWR of 3 to 6 in the flight regime where a TSTO upper stage has a TWR of 0.6 to 0.9.

But the SSTO has considerably worse mass fractions compared to a TSTO after staging, so the reduced gravity loss isn't a net win: payload as a fraction of GLOM is still very low. And burnout acceleration is extremely high... 10 to 15g, perhaps higher if unthrottled?

Online Davidthefat

Re: ARCA Space Corporation
« Reply #54 on: 04/11/2017 04:22 PM »
I'm starting to think that ARCA is actually a video/CGI production company that likes to advertise by making videos of fanciful rockets.

The CGI isn't even that good honestly...

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #55 on: 04/11/2017 04:48 PM »
The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.

It helps a lot, since gravity losses are reduced, meaning less delta-V is required to reach orbit.

That's at best an internal advantage, not an external advantage.  What I mean is that at best that helps them with something else that would matter to a payload.  For example, if it meant less propellant, maybe that means less cost.  It's the less cost that actually matters.  So taking less time to get to orbit isn't by itself something that matters, it's, at best, an aid in something else that actually matters.  So it's not something that justifies being trumpeted as an advantage of ARCA's proposed launch system.  If it helps them lower costs, let them claim the lower costs.

As another poster pointed out, this is just one factor and optimizing for lower time to orbit might bring disadvantages that more than make up for the reduced gravity losses.  Other launch providers have made different trade-offs, so others seem to think it's better to have the higher gravity losses in exchange for other benefits.

Online FutureSpaceTourist

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Re: ARCA Space Corporation
« Reply #56 on: 04/20/2017 06:31 AM »

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #57 on: 04/20/2017 08:07 AM »
Another ARCA piece:

http://krqe.com/2017/04/18/new-mexico-rocket-seeks-historic-first/

The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

That unbelievable claim comes right after the article says, "ARCA also does away with cryogenic fuels, the traditional super-cold liquid hydrogen and oxygen used by many space vehicles today. Instead, the Haas 2CA will use kerosene and hydrogen peroxide, which do not need to be kept cold."  Which seems to imply that they're claiming 30% better Isp than hydrolox for kerosene and hydrogen peroxide.

Online Steven Pietrobon

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Re: ARCA Space Corporation
« Reply #58 on: 04/21/2017 06:44 AM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline savuporo

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Re: ARCA Space Corporation
« Reply #59 on: 04/21/2017 06:56 AM »
Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I don't think that's what they meant. I highly doubt anyone of that team speaks rocket.
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Online envy887

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Re: ARCA Space Corporation
« Reply #60 on: 04/21/2017 01:27 PM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I'm pretty sure they meant this:

Quote
A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust.

http://www.ijmetmr.com/olseptember2016/SudarsanGajula-KBabitha-KBharadwajan-225.pdf

Online Lars-J

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Re: ARCA Space Corporation
« Reply #61 on: 04/21/2017 05:24 PM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I'm pretty sure they meant this:

Quote
A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust.

http://www.ijmetmr.com/olseptember2016/SudarsanGajula-KBabitha-KBharadwajan-225.pdf

If that was true - and there weren't other tradeoffs to make - every launch vehicle would be using aerospike engines. And despite being tested off and on since the 60's, there has been exactly ZERO launch vehicles with aerospike engines.

« Last Edit: 04/21/2017 08:54 PM by Lars-J »

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #62 on: 04/21/2017 06:10 PM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I'm pretty sure they meant this:

Quote
A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust.

http://www.ijmetmr.com/olseptember2016/SudarsanGajula-KBabitha-KBharadwajan-225.pdf

This paper doesn't explain that quote at all.  My best guess is that it means 25-30% less fuel compared with a vacuum-optimized engine with the same thrust.  After all, being able to use the same engine at sea level and vacuum is the one big advantage of an aerospike.

Of course, the way ARCA used the 30% figure in the quote in the article, it implied that they'll get some sort of 30% improvement compared with other launch vehicles, which is just silly because other launch vehicles aren't using a vacuum engine at sea level.

Online envy887

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Re: ARCA Space Corporation
« Reply #63 on: 04/21/2017 09:35 PM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I'm pretty sure they meant this:

Quote
A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust.

http://www.ijmetmr.com/olseptember2016/SudarsanGajula-KBabitha-KBharadwajan-225.pdf

This paper doesn't explain that quote at all.  My best guess is that it means 25-30% less fuel compared with a vacuum-optimized engine with the same thrust.  After all, being able to use the same engine at sea level and vacuum is the one big advantage of an aerospike.

Of course, the way ARCA used the 30% figure in the quote in the article, it implied that they'll get some sort of 30% improvement compared with other launch vehicles, which is just silly because other launch vehicles aren't using a vacuum engine at sea level.
ARCA probably got their information from the Wikipedia article on aerospikes, which has the exact same quote. I doubt they have a better answer in any context.

Offline as58

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Re: ARCA Space Corporation
« Reply #64 on: 04/22/2017 08:23 PM »
The article says "Between the engine and the fuels, Popescu says his engine is 30 percent more fuel efficient than today’s traditional engines."  Anyone have any idea how they justify that?

Maybe they meant impulse density? HTP/Kero can be have up to 15% greater impulse density than LOX/Kero.

I'm pretty sure they meant this:

Quote
A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust.

http://www.ijmetmr.com/olseptember2016/SudarsanGajula-KBabitha-KBharadwajan-225.pdf

This paper doesn't explain that quote at all.  My best guess is that it means 25-30% less fuel compared with a vacuum-optimized engine with the same thrust.  After all, being able to use the same engine at sea level and vacuum is the one big advantage of an aerospike.

Of course, the way ARCA used the 30% figure in the quote in the article, it implied that they'll get some sort of 30% improvement compared with other launch vehicles, which is just silly because other launch vehicles aren't using a vacuum engine at sea level.
ARCA probably got their information from the Wikipedia article on aerospikes, which has the exact same quote. I doubt they have a better answer in any context.

M.Tech Gajula and professors Babitha and Bharadwajan would be well advised to think carefully what plagiarism means. The whole intro of the paper has a bit too much similarity to the wikipedia article.

Offline meekGee

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Re: ARCA Space Corporation
« Reply #65 on: 04/24/2017 05:52 AM »
The focus on 5 minutes to orbit instead of 8 is also really bizarre -- as if that matters in any way whatsoever.

It helps a lot, since gravity losses are reduced, meaning less delta-V is required to reach orbit.

How many seconds of these 3 minutes are saved during the vertical portion of the flight?

But yes, for a hypothetical SSTO, every little bit matters a lot.
ABCD - Always Be Counting Down

Offline ringsider

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Re: ARCA Space Corporation
« Reply #66 on: 04/24/2017 06:23 AM »
M.Tech Gajula and professors Babitha and Bharadwajan would be well advised to think carefully what plagiarism means. The whole intro of the paper has a bit too much similarity to the wikipedia article.

Wow. Except for half a dozen words in one sentence, it is exactly the same.

https://en.wikipedia.org/wiki/Aerospike_engine

Offline Phil Stooke

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Re: ARCA Space Corporation
« Reply #67 on: 04/24/2017 01:51 PM »
Do we know which came first? 

Online LouScheffer

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Re: ARCA Space Corporation
« Reply #68 on: 04/24/2017 02:37 PM »
M.Tech Gajula and professors Babitha and Bharadwajan would be well advised to think carefully what plagiarism means. The whole intro of the paper has a bit too much similarity to the wikipedia article.

Indeed:  Here is the intro to their paper.  Words identical to Wikipedia are in bold.  Wikipedia text is in brackets.

The aerospike engine is a type of rocket engine that maintains its aerodynamic efficiency within [across] a wide range of altitudes. It is a member of the class of altitude that compensaties [compensating] nozzle engines. A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust. Aerospike engines have been studied for a number of years and are the baseline engines for many single-stage-to-orbit (SSTO) designs and were also a strong contender for the Space Shuttle Main Engine. However, no such engine is in commercial production, although some large-scale aerospike’s [ s] are in testing phases.

That's more than 100 words of extremely similar text.  The small differences that are present look like an attempt to avoid direct copying, since they do not improve the text but in fact make it worse by introducing spelling and punctuation errors.  This text was in Wikipedia as of 2012, while their article was in 2016, so almost surely their text was copied from Wikipedia and not vice versa.  Such a large stretch of uncredited identical text would constitute plagiarism in many academic contexts.

Wikipedia is *not* public domain.  You are free to use it, in any manner you like, but you need to give credit.   The license states:
Quote
You are free:

to Share—to copy, distribute and transmit the work, and
to Remix—to adapt the work
for any purpose, even commercially.

Under the following conditions:

Attribution—You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work.) [...]
I can't find any reference of any kind to Wikipedia in their article.

Offline JH

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Re: ARCA Space Corporation
« Reply #69 on: 04/24/2017 04:00 PM »
I know that plagiarism is rampant in less well known publications, but the editor(s) of the journal should be notified.

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Re: ARCA Space Corporation
« Reply #70 on: 04/24/2017 07:39 PM »
OK, this is not funny.  On a hunch, I checked some of the following text.  Again, it almost exactly matched another publication, but this one is not WIkipedia, it's an uncredited academic paper.  Parts in bold are identical to words in
Design and Numerical Analysis of Aerospike Nozzleswith Different Plug Shapes to Compare theirPerformance with a Conventional Nozzle, by  Mehdi Nazarinia, Arash Naghib-Lahouti, and Elhaum Tolouei

Expansion and discharge of a gas in different propulsion systems, e.g. jet engines and rockets, is always accomplished by a nozzle. Thrust of available from a conventional fixed nozzle, discharging jet to [ in]atmosphere can be expressed by the following simple  relation:
F = ṁeVe - ṁoVo+ (PeAe - PatmAExt) (1)
For a nozzle designed to operate at constant Pe (also known as design exhaust pressure, Pdes), thrust is affected
due to altitude change with respect to operation [by change of altitude]. At the design altitude, where Patm = Pdes, the second term of the above relation (known as pressure thrust) is zero, and the nozzle is said to be working in “optimum condition”. At altitudes lower than the design altitude, where Patm>Pdes, pressure thrust assumes a negative value, and loss of thrust is inevitable. These conditions, which occur at altitudes ranging from ground level to the design altitude, are known as over-expansion conditions. Due to in-built thrust losses, [Besides the inherent loss of thrust] the conventional nozzle might suffer problems including shock waves, flow separation in divergent section; thrust oscillation; and flow asymmetry in over-expansion conditions.

From their results and discussion: (compare to results and discussion of cited paper above)

In this section, flow pattern of the ideal aerospike nozzle in different working conditions is compared to that of the truncated aerospike and conventional nozzles. [...] Exhaust flow of the aerospike nozzle is characterized by formation of a series of expansion waves, which originate from the upper lip of the convergent section. Since the exhaust flow is not bounded by a solid wall, these expansion waves can adjust their intensity and domain to match the exhaust flow with the external flow.  For the ideal aerospike, in over-expansion conditions, the domain covered by these waves ends before the end of the plug. At that station, flow properties are close to those of the optimum condition, which usually involve a higher Mach number and a lower pressure compared to the external flow. From this station onwards, flow encounters reflection of the expansion waves in form of a series of compression waves, which increase the pressure and reduce Mach number to a value close to that of the external flow. [..] But for the truncated aerospike nozzles, the situation is such that the expansion waves originated from the upper lip of the convergent section will face the truncated portion of the plug, while in the ideal case these expansion waves meet the plug surface. The flow facing the truncation first encounters a sharp expansion, then by continuing its way to the centre of the plug base a compression, stagnating exactly at the centre of the plug base. This phenomenon is due to the formation of two symmetric vortices in the base of the plug, which counteract the effect of each other at two locations, one of which is located at the centre of the plug base, where flow conditions change into the stagnation conditions. It should be pointed out that regardless of the amount of truncation and the extent of the plug base area, the flow parameter distribution pattern is the same. [..] The exhaust flow of a conventional nozzle, on contrary, does not have the chance to adapt itself to the condition prevailing outside the nozzle before leaving the nozzle. After leaving the nozzle, flow is compressed through a series of compression waves originating from the edge of the exhaust surface, which resemble converging shock waves. These compression waves contract the flow, and impose a radial velocity component, which contributes to loss of thrust in over-expansion conditions.

This goes on and on - the next paragraph matches as well.  I'm writing a letter to the editor.

Online LouScheffer

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Re: ARCA Space Corporation
« Reply #71 on: 04/24/2017 08:10 PM »
OK, this is not funny.  On a hunch, I checked some of the following text.  Again, it almost exactly matched another publication, but this one is not WIkipedia, it's an uncredited academic paper.  Parts in bold are identical to words in Design and Numerical Analysis of Aerospike Nozzleswith Different Plug Shapes to Compare their Performance with a Conventional Nozzle, by  Mehdi Nazarinia, Arash Naghib-Lahouti, and Elhaum Tolouei
[...]

This goes on and on - the next paragraph matches as well.  I'm writing a letter to the editor.
The editor wrote back, very quickly.  They will investigate, and (potentially) remove the article in whole or in part.  They will reply with their actions within 7 business days.  I'm glad they are treating this seriously.

Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #72 on: 04/25/2017 10:05 PM »
This sort of thread reminds me of how great NSF can be. The (likely) ferreting out of a (likely) dastard plagiarist in real time.

Matthew

Offline savuporo

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« Last Edit: 05/17/2017 12:37 AM by launchwatcher »

Offline CameronD

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Re: ARCA Space Corporation
« Reply #75 on: 05/16/2017 11:03 PM »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.


Offline Craftyatom

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Re: ARCA Space Corporation
« Reply #77 on: 05/17/2017 01:42 AM »
Lol

https://twitter.com/arcaspace/status/864485699810058241

I tried to find some source on the picture they used there, since I couldn't quite tell if it was superb CGI or a mockup.  I now have no doubt that this is actually a real-life mockup that they built and put on a truck.  Two reasons: first, an example of their CGI is attached, which is pretty recognizable.  Second, they've built a mockup orbital launch vehicle before - back in 2012, when they were testing a standard de Laval nozzle that burned kerolox in a TSTO configuration.  Picture of that attached too.

At first I was running around trying to find hi-res versions of these pictures on Romanian news sites, but it turns out that ARCA's website still has the default index page set for their /images/ folder, so you can actually go through all of their images pretty easily: http://www.arcaspace.com/images/

But why spend time sifting through images when we could all be hopping on that sweet $5.3B gravy train?  ;D
All aboard the HSF hype train!  Choo Choo!

Offline GWH

Re: ARCA Space Corporation
« Reply #78 on: 05/17/2017 04:53 AM »
Lol

https://twitter.com/arcaspace/status/864485699810058241

I tried to find some source on the picture they used there, since I couldn't quite tell if it was superb CGI or a mockup.  I now have no doubt that this is actually a real-life mockup that they built and put on a truck.   

It is a real mock up, they posted a video of them ceremoniously offloading it into a hanger but then people made fun of them because is is obviously juat a painted tube and now its not on their twitter.
 
Edit: There it is, on their youtube:
« Last Edit: 05/17/2017 04:59 AM by GWH »

Offline savuporo

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Re: ARCA Space Corporation
« Reply #79 on: 05/17/2017 05:51 AM »
..It is a real mock up..
That's kind of their thing.
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Offline ringsider

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Re: ARCA Space Corporation
« Reply #80 on: 05/17/2017 06:17 AM »
..It is a real mock up..
That's kind of their thing.
This will seem odd from me, but I don't mind mock-ups or engineering models as long as they are clearly labelled.

Rocket Lab's original coming out party showed a mock-up rocket - the nose cone was obviously wrong and there was probably nothing behind the engine blanking plate.

Where it goes wrong is pretending that the vehicle is real, to raise money. That's highly questionable at best, fraud at worst.

Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #81 on: 05/17/2017 12:26 PM »

Offline Katana

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Re: ARCA Space Corporation
« Reply #82 on: 05/18/2017 05:48 PM »
..It is a real mock up..
That's kind of their thing.
This will seem odd from me, but I don't mind mock-ups or engineering models as long as they are clearly labelled.

Rocket Lab's original coming out party showed a mock-up rocket - the nose cone was obviously wrong and there was probably nothing behind the engine blanking plate.

Where it goes wrong is pretending that the vehicle is real, to raise money. That's highly questionable at best, fraud at worst.

Rlabs have engine tests frequently, ARCA have almost none.

Offline ringsider

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Re: ARCA Space Corporation
« Reply #83 on: 05/18/2017 05:52 PM »
..It is a real mock up..
That's kind of their thing.
This will seem odd from me, but I don't mind mock-ups or engineering models as long as they are clearly labelled.

Rocket Lab's original coming out party showed a mock-up rocket - the nose cone was obviously wrong and there was probably nothing behind the engine blanking plate.

Where it goes wrong is pretending that the vehicle is real, to raise money. That's highly questionable at best, fraud at worst.

Rlabs have engine tests frequently, ARCA have almost none.
They did eventually, sure I'm not comparing them directly. Just saying there is a place for a cheap mock up, as long as it is not positioned as the real thing. PLD Space has one in their office as well. More of a visual aid than anything else, like every image of a movie director has a camera in it.
« Last Edit: 05/18/2017 05:52 PM by ringsider »

Offline CameronD

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Re: ARCA Space Corporation
« Reply #84 on: 05/19/2017 02:59 AM »
They did eventually, sure I'm not comparing them directly. Just saying there is a place for a cheap mock up, as long as it is not positioned as the real thing. PLD Space has one in their office as well. More of a visual aid than anything else, like every image of a movie director has a camera in it.

FWIW, RocketLab's mockup is mounted horizontally out front of their office in 10 Airpark Drive, Auckland and has been for some time now.  Unfortunately I note it doesn't show on Google Street-view, but those pics do seem to be several years old.
 

« Last Edit: 05/19/2017 03:00 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline GWH

Re: ARCA Space Corporation
« Reply #85 on: 05/26/2017 10:59 PM »
ARCA is seeking investment from New Mexico residents:

On their site they have a timeline poste: http://arcaspace.com/
Critical design review this month - first flight October 2018 & commercial ops that December :o

Offline buraianto

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Re: ARCA Space Corporation
« Reply #86 on: 05/28/2017 03:56 AM »
The following are scheduled to be finished by May 2017. If they are meeting their schedule they should be just about done with these tasks.

Quote
- Release the final design;
- Release final test planning for Haas 2CA and associated hardware;
- Release the integration and operations procedures;
- Authorise manufacturing.

Note what has yet to take place, being scheduled for May this year to August 2018.

Quote
Build three Executor Aerospike engines for sea level tests and the test article;

Online LouScheffer

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Re: ARCA Space Corporation
« Reply #87 on: 06/05/2017 01:09 PM »
OK, this is not funny.  On a hunch, I checked some of the following text.  Again, it almost exactly matched another publication, but this one is not WIkipedia, it's an uncredited academic paper.  Parts in bold are identical to words in Design and Numerical Analysis of Aerospike Nozzleswith Different Plug Shapes to Compare their Performance with a Conventional Nozzle, by  Mehdi Nazarinia, Arash Naghib-Lahouti, and Elhaum Tolouei
[...]

This goes on and on - the next paragraph matches as well.  I'm writing a letter to the editor.
The editor wrote back, very quickly.  They will investigate, and (potentially) remove the article in whole or in part.  They will reply with their actions within 7 business days.  I'm glad they are treating this seriously.
OK, heard back from the editor.  They asked the authors for an explanation, got no response, and are pulling the article in its entirety..

Offline GWH

Re: ARCA Space Corporation
« Reply #88 on: 06/16/2017 01:14 AM »
Arca has a new video up, talking about ramping up to fly a aerospike on a smaller dev vehicle from New Mexico in 2 months.
-Video shows them building a nose cone and a dome
-3:50 show some Iridium electronics modules and some microprocessor boards from Sparkfun.com
-No engine hardware shown

Offline savuporo

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Re: ARCA Space Corporation
« Reply #89 on: 06/16/2017 01:47 AM »
-3:50 show some Iridium electronics modules and some microprocessor boards from Sparkfun.com

You left out the important part. Live action from interns booting stock Raspbian distro on Rpi. This has never been done before
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Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #90 on: 06/16/2017 02:01 AM »
The thing that struck me the most in the video was how empty the electronics lab was.  I've never seen a room where people were working on electronics that wasn't filled with all the components and instruments that would fit.  But here was a guy sitting at a table working on avionics in a nearly empty room.  The cabinets in the background were all full of spacecraft models, not electronic components or instruments or tools.  Every piece of equipment related to electronics that was visible fit comfortably on the one table in the room.

Offline Chasm

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Re: ARCA Space Corporation
« Reply #91 on: 06/18/2017 01:42 PM »
The moment where you have more assorted electronics parts on your desk than a real(*) rocket engineer on the workbench. Less parts from eBay/Banggood too!
* As seen on TV The Internet

What I found really bad was the mold building. Say at @1:37. Such holes are just unnecessary. Composite construction is also very old school. Just having a slight insight into boat building technology there is so much that could be improved by hiring just one or two of their guys (or gals!) for a week or two. :-\ No need to go for the latest Americas Cup racing boat technology either, a decade or two or so ago will do...

But then I wake up and remember that it's ARCA. They are obviously in a different business. 8)

Offline TrevorMonty

Re: ARCA Space Corporation
« Reply #92 on: 06/18/2017 07:38 PM »
Arca are planning suborbital flights in few months to test engine and systems. Any company that can demonstrate flying HW even if it is suborbital is worth taking note of.

http://www.parabolicarc.com/2017/06/18/arca-space-test-aerospike-engine-spaceport-america/#more-61833

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #93 on: 06/18/2017 08:21 PM »
Arca are planning suborbital flights in few months to test engine and systems. Any company that can demonstrate flying HW even if it is suborbital is worth taking note of.

http://www.parabolicarc.com/2017/06/18/arca-space-test-aerospike-engine-spaceport-america/#more-61833

Lets not count our chickens before they're hatched -- Arca has not yet flown.  They've promised flights before that never materialized.

Maybe this time will be different and they'll actually fly, or maybe it will be another empty promise from Arca.  I'm withholding judgement until I see it.

It's also worth noting that while flying something into space on a suborbital trajectory is better than flying nothing, it's also pretty easy compared with getting something to orbit, and getting something to orbit is pretty easy compared to single-stage to orbit.  Arca is promising single-stage to orbit (HASS 2CA) in 2018.  The most charitable thing that can be said about that claim is that it's ambitious.

Offline josespeck

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Re: ARCA Space Corporation
« Reply #94 on: 06/19/2017 05:14 PM »



Is that fiberglass?. Would not it be better to use carbon fiber?.

Online Davidthefat

Re: ARCA Space Corporation
« Reply #95 on: 06/19/2017 05:20 PM »
Arca are planning suborbital flights in few months to test engine and systems. Any company that can demonstrate flying HW even if it is suborbital is worth taking note of.

http://www.parabolicarc.com/2017/06/18/arca-space-test-aerospike-engine-spaceport-america/#more-61833

Lets not count our chickens before they're hatched -- Arca has not yet flown.  They've promised flights before that never materialized.

Maybe this time will be different and they'll actually fly, or maybe it will be another empty promise from Arca.  I'm withholding judgement until I see it.

It's also worth noting that while flying something into space on a suborbital trajectory is better than flying nothing, it's also pretty easy compared with getting something to orbit, and getting something to orbit is pretty easy compared to single-stage to orbit.  Arca is promising single-stage to orbit (HASS 2CA) in 2018.  The most charitable thing that can be said about that claim is that it's ambitious.


Looks like they won't even use flight engine module for the suborbital flight... They are just decomposing the peroxide with a catalyst instead of using kerosene as a fuel...

Blow down with peroxide decomposition given their previous statements. Just literally a "let 'er rip" type of thing.

Online Welsh Dragon

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Re: ARCA Space Corporation
« Reply #96 on: 06/19/2017 05:37 PM »
I keep wondering why they're proposing a linear aerospike. Wouldn't a toroidal one be lighter on a conventional rocket? Or are there performance benefits of linear over toroidal? Also, I just keep looking at that linear spike and thinking the airflow over the width of it must vary considerably, being under a cylindrical body. Would imply varying expansion ratios, and loss of efficiency, surely?

Online Davidthefat

Re: ARCA Space Corporation
« Reply #97 on: 06/19/2017 06:25 PM »
I keep wondering why they're proposing a linear aerospike. Wouldn't a toroidal one be lighter on a conventional rocket? Or are there performance benefits of linear over toroidal? Also, I just keep looking at that linear spike and thinking the airflow over the width of it must vary considerably, being under a cylindrical body. Would imply varying expansion ratios, and loss of efficiency, surely?

Are you assuming that they are actually intending to fly the full scale thing?

It's easier to do a cash grab when taking "proven" technologies and presenting them as ideas instead of going down a different path. Especially given how much they referenced the X-33 engine in their promotional videos, they want to give the impression that it's feasible.

Also not to look like a Firefly copy I suppose.

Online Welsh Dragon

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Re: ARCA Space Corporation
« Reply #98 on: 06/19/2017 06:35 PM »
Well, I guess I was assuming that even a cash grab needs some technical plausibility, but you're right, a fool and his money are easily parted.

Offline jeffreycornish

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Re: ARCA Space Corporation
« Reply #99 on: 06/19/2017 06:48 PM »



Is that fiberglass?. Would not it be better to use carbon fiber?.

It's a suborbital demonstrator to look at the performance and characteristics of the engine.  This is a small company and carbon fiber is more expensive than fiberglass. 

They are _not_ building the orbital vehicle here.  They need an airframe that is 'good enough'--not perfect.

I can fully appreciate using a less expensive material for test.

Offline GWH

Re: ARCA Space Corporation
« Reply #100 on: 06/19/2017 08:54 PM »
Is that fiberglass?. Would not it be better to use carbon fiber?.

It's a suborbital demonstrator to look at the performance and characteristics of the engine.  This is a small company and carbon fiber is more expensive than fiberglass. 

They are _not_ building the orbital vehicle here.  They need an airframe that is 'good enough'--not perfect.

I can fully appreciate using a less expensive material for test.

It isn't their orbital engine though, this is just a mono-prop with 70% concentration H2O2.

Offline TrevorMonty

Re: ARCA Space Corporation
« Reply #101 on: 06/19/2017 11:52 PM »
Is that fiberglass?. Would not it be better to use carbon fiber?.

It's a suborbital demonstrator to look at the performance and characteristics of the engine.  This is a small company and carbon fiber is more expensive than fiberglass. 

They are _not_ building the orbital vehicle here.  They need an airframe that is 'good enough'--not perfect.

I can fully appreciate using a less expensive material for test.

It isn't their orbital engine though, this is just a mono-prop with 70% concentration H2O2.
It will still be flying a aerospike engine. Not something that hasn't happened for a long time.

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #102 on: 06/20/2017 12:43 AM »
I can fully appreciate using a less expensive material for test.

OK, but they're claiming they'll fly the orbital vehicle in 2018.  Their test program should be using the materials they're really planning to use if they were serious about a SSTO flight in 2018.  99.9% of what they need to develop to do their claimed 2018 plans isn't being tested by this vehicle.  That's a problem.

Online Skyrocket

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Re: ARCA Space Corporation
« Reply #103 on: 06/20/2017 11:03 AM »
Has anyone an idea, if there might be a reason for these strange tandem fins on the Demonstrator-3 except from looking somewhat cool?

Offline josespeck

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Re: ARCA Space Corporation
« Reply #104 on: 06/20/2017 05:16 PM »


It's a suborbital demonstrator to look at the performance and characteristics of the engine.  This is a small company and carbon fiber is more expensive than fiberglass. 

They are _not_ building the orbital vehicle here.  They need an airframe that is 'good enough'--not perfect.

I can fully appreciate using a less expensive material for test.

Resistance to pressure will be worse than carbon fiber. Or does SpaceX want to pay more?.

Offline Craftyatom

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Re: ARCA Space Corporation
« Reply #105 on: 06/20/2017 05:25 PM »


It's a suborbital demonstrator to look at the performance and characteristics of the engine.  This is a small company and carbon fiber is more expensive than fiberglass. 

They are _not_ building the orbital vehicle here.  They need an airframe that is 'good enough'--not perfect.

I can fully appreciate using a less expensive material for test.

Resistance to pressure will be worse than carbon fiber. Or does SpaceX want to pay more?.

Again, they don't need a top-of-the-line solution because this is not an orbital mission like SpaceX.  It's a suborbital vehicle, they can build as much margin into it as they want.  The decision to use fiberglass might reduce the vehicle's apogee, but as long as it exceeds 100km, the mission is a success.  Using carbon fiber would not appreciably increase the chance of mission success - but using a lower-cost option greatly increases the chance that the mission happens at all.

I can fully appreciate using a less expensive material for test.

OK, but they're claiming they'll fly the orbital vehicle in 2018.  Their test program should be using the materials they're really planning to use if they were serious about a SSTO flight in 2018.  99.9% of what they need to develop to do their claimed 2018 plans isn't being tested by this vehicle.  That's a problem.


Agreed, if they were to launch orbital in 2018, then they should be getting experience with tooling and construction now.  That said, I don't think anyone here is too confident in them actually launching an orbital LV within the next 560 days.
All aboard the HSF hype train!  Choo Choo!

Offline matthewkantar

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Re: ARCA Space Corporation
« Reply #106 on: 06/20/2017 06:15 PM »
Another video from YouTube:

After viewing this and the previous videos featured in this thread, my biggest fear as a potential investor would be of ARCA spending all of my money on toys. Seems like the shelves in every room are full of them.

Matthew

Offline savuporo

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Re: ARCA Space Corporation
« Reply #107 on: 06/20/2017 06:56 PM »
..my biggest fear as a potential investor would be of ARCA spending all of my money on toys. ..
Or spending more money hiring promotional models for videos than hiring engineers. Or having interns breathe fiberglass dust and wearing no protection. Or not actually building any of the products they make promotional videos about etc.
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Online Lars-J

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Re: ARCA Space Corporation
« Reply #108 on: 06/20/2017 09:19 PM »
These guys are vaporware until they show engine tests.

Offline GWH

Re: ARCA Space Corporation
« Reply #109 on: 06/20/2017 09:46 PM »
While I am really skeptical on ARCA Space - the basic design and non-cryo propellant combo scaled up would make a really good fit for that other improbable launch system: Stratolaunch. 

Offline Craftyatom

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Re: ARCA Space Corporation
« Reply #110 on: 06/21/2017 08:01 PM »
While I am really skeptical on ARCA Space - the basic design and non-cryo propellant combo scaled up would make a really good fit for that other improbable launch system: Stratolaunch.

The aerospike design doesn't really lend itself to air launch - launching from 30000 feet AMSL means that you start in 1/3rd atmospheric pressure, so underexpansion is less of an issue.  The difference might not be that much, but it could tip the scales on the mass vs. Isp tradeoff.

Non-cryo propellants, however, would indeed be great for airlaunch, and the composite tooling means that it would act as a good "upper stage" after the air-launch "first stage".  I'd bet, though, that you'd get more performance out of an air-launch version using a conventional de Laval nozzle.

But then, if we're changing the design anyways, then we should just make it a two-stage rocket.  SSTO has never had any real purpose besides ease of reuse, and as far as we know reuse is nowhere on the horizon for this team. (do linear aerospikes even work when flying backwards supersonic?  I have a feeling it would mess up the flow dynamics, but then, the exhaust is significantly faster/denser than the surrounding air, so maybe not).
All aboard the HSF hype train!  Choo Choo!

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #111 on: 06/21/2017 10:36 PM »
While I am really skeptical on ARCA Space - the basic design and non-cryo propellant combo scaled up would make a really good fit for that other improbable launch system: Stratolaunch.

Two bad ideas for launch companies put together doesn't equal a good idea.

Offline meekGee

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Re: ARCA Space Corporation
« Reply #112 on: 06/24/2017 09:47 PM »
While I am really skeptical on ARCA Space - the basic design and non-cryo propellant combo scaled up would make a really good fit for that other improbable launch system: Stratolaunch.

Two bad ideas for launch companies put together doesn't equal a good idea.

Yeah, but it reduces the amount of collateral hassle.
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Offline GWH

Re: ARCA Space Corporation
« Reply #113 on: 06/24/2017 10:11 PM »
So they posted up another video: they claimed that the propellant tanks are the lightest around and the demonstration vehicle will be the same as the orbital yet it also looks like fiberglass... so not sure what the case is.

These guys seem a lot like Copenhagen suborbital. Just barely a step above high powered rocketry enthusiasts.  In  the unlikely event that they get to orbit it would be a huge step forward for amateurs and dreamers.

Offline savuporo

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Re: ARCA Space Corporation
« Reply #114 on: 06/24/2017 11:07 PM »
These guys seem a lot like Copenhagen suborbital. Just barely a step above high powered rocketry fiberglass enthusiasts. 

More accurate now
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Offline Klebiano

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Re: ARCA Space Corporation
« Reply #115 on: 06/25/2017 12:49 AM »
So they posted up another video: they claimed that the propellant tanks are the lightest around and the demonstration vehicle will be the same as the orbital yet it also looks like fiberglass... so not sure what the case is.

These guys seem a lot like Copenhagen suborbital. Just barely a step above high powered rocketry enthusiasts.  In  the unlikely event that they get to orbit it would be a huge step forward for amateurs and dreamers.

The accelerometer that is shown in the video can be found here: https://www.sparkfun.com/products/retired/10736

I wonder if these hobby-focused devices are recommended to be the INS in such an expensive project.

Offline GWH

Re: ARCA Space Corporation
« Reply #116 on: 06/26/2017 05:24 PM »
Regarding the construction they answered my question on using fiberglass for both vehicles:

Quote from: ARCA SPACE CORPORATION
The Haas 2CA orbital launcher will be using the same composites as the Demonstrator 3. While carbon fiber would be a little more rigid, the fiberglass composites we are using have a higher strength to weight ratio, overall. And they are less expensive.


Online Kansan52

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Re: ARCA Space Corporation
« Reply #117 on: 06/26/2017 08:50 PM »
I love steam rockets, no matter how hard they are to get to work.

Online ChrisWilson68

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Re: ARCA Space Corporation
« Reply #118 on: 06/27/2017 03:06 AM »
Regarding the construction they answered my question on using fiberglass for both vehicles:

Quote from: ARCA SPACE CORPORATION
The Haas 2CA orbital launcher will be using the same composites as the Demonstrator 3. While carbon fiber would be a little more rigid, the fiberglass composites we are using have a higher strength to weight ratio, overall. And they are less expensive.

ARCA is fascinating to watch because you never know what sort of craziness will come next.

It's just too bad they're trying to con ordinary people in New Mexico out of their hard-earned cash for their hair-brained schemes.

Online Welsh Dragon

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Re: ARCA Space Corporation
« Reply #119 on: 06/27/2017 07:45 AM »
ARCA is fascinating to watch because you never know what sort of craziness will come next.

It's just too bad they're trying to con ordinary people in New Mexico out of their hard-earned cash for their hair-brained schemes.
I miss the days of the stealth-supersonic-seaplane-with-SS1-nose-air-launch..... The current iteration just seems boring in comparison.

Offline ringsider

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Re: ARCA Space Corporation
« Reply #120 on: 06/27/2017 09:56 PM »
Regarding the construction they answered my question on using fiberglass for both vehicles:

Quote from: ARCA SPACE CORPORATION
The Haas 2CA orbital launcher will be using the same composites as the Demonstrator 3. While carbon fiber would be a little more rigid, the fiberglass composites we are using have a higher strength to weight ratio, overall. And they are less expensive.

They refer to specific strength. I don't think that istrue, CFRP is lighter for the same yield than GFRP. 

Fun fact: balsa has a higher specfic strength than titanium.

Online meberbs

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Re: ARCA Space Corporation
« Reply #121 on: 06/27/2017 11:07 PM »
Regarding the construction they answered my question on using fiberglass for both vehicles:

Quote from: ARCA SPACE CORPORATION
The Haas 2CA orbital launcher will be using the same composites as the Demonstrator 3. While carbon fiber would be a little more rigid, the fiberglass composites we are using have a higher strength to weight ratio, overall. And they are less expensive.

They refer to specific strength. I don't think that istrue, CFRP is lighter for the same yield than GFRP. 

Fun fact: balsa has a higher specfic strength than titanium.
It looks like an S-glass/epoxy composite can get close to the strength to weight ratio for carbon/epoxy, but their statement is still wrong.
http://www.carbonfibertubeshop.com/tube%20properties.html

Also, your mileage may vary on that balsa fact. It may be true, but this site disagrees. If you check the source of the numbers on the Wikipedia table, you see that while Balsa is really high on the list, this is only along the grain, and it is very bad perpendicular, severely limiting its usefulness. (Relatedly, fiber direction also matters for composites, the reference above at least should be apples-to-apples for the S-glass vs carbon fiber, but there is no such thing as apples to apples for titanium and balsa.)

Online envy887

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Re: ARCA Space Corporation
« Reply #122 on: Today at 03:51 PM »
Regarding the construction they answered my question on using fiberglass for both vehicles:

Quote from: ARCA SPACE CORPORATION
The Haas 2CA orbital launcher will be using the same composites as the Demonstrator 3. While carbon fiber would be a little more rigid, the fiberglass composites we are using have a higher strength to weight ratio, overall. And they are less expensive.

They refer to specific strength. I don't think that istrue, CFRP is lighter for the same yield than GFRP. 

Fun fact: balsa has a higher specfic strength than titanium.
It looks like an S-glass/epoxy composite can get close to the strength to weight ratio for carbon/epoxy, but their statement is still wrong.
http://www.carbonfibertubeshop.com/tube%20properties.html

Also, your mileage may vary on that balsa fact. It may be true, but this site disagrees. If you check the source of the numbers on the Wikipedia table, you see that while Balsa is really high on the list, this is only along the grain, and it is very bad perpendicular, severely limiting its usefulness. (Relatedly, fiber direction also matters for composites, the reference above at least should be apples-to-apples for the S-glass vs carbon fiber, but there is no such thing as apples to apples for titanium and balsa.)

Titanium can have grain direction, depending how it's been worked. But the effects aren't as significant as wood or composites.

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