Rocket Factory Augsburg

[tater]

https://www.rfa.space/

 

 

 

 

 

 

 

Edited August 31, 2021 by tater

[AngrybobH]

Do you know anything else about these guys? Like timeline to orbit or if they are trying for reuse? I poked around on their site a bit and, while interesting, it was basically PR stuff, nothing much concrete. The impression I took from it was build 'em fast and cheap and dump 'em in the ocean when done. I don't suppose on a small enough scale that is all that bad.  It is nice to see more companies trying for the cheaper access to space.

[kerbiloid]

Googling "Rocket Factory Augsburg" for Images,

Spoiler

They can start from sky below to high-ground above.


They have funny things to look through.

They are fond of SFX.

 

Their rocket is actually three-stage.

Count yourself. One, two, three.

 

Polish activities. They need a lot of them.

 

ET rent them, too.

 

Edited August 31, 2021 by kerbiloid

[Rocket Factory Augsburg]

 

Quote

Do you know anything else about these guys? Like timeline to orbit or if they are trying for reuse? I poked around on their site a bit and, while interesting, it was basically PR stuff, nothing much concrete. The impression I took from it was build 'em fast and cheap and dump 'em in the ocean when done. I don't suppose on a small enough scale that is all that bad.  It is nice to see more companies trying for the cheaper access to space.

Hi AngrybobH,

Yes, we build them fast and as inexpensive as possible (stainless steel), but we plan on reusing our first stage extensively. On the first flight(s) though, we focus on reaching orbit.

What generally sets us apart are three things: a) our staged combustion engine, which gives us more performance and efficiency and up to 30% more payload-to-orbit capacity, b) our stainless steel structure, which allows for reusability but is also cheap and easy to process - perfect for mass production of a rocket, and c) our orbital stage, which allows us to put our customers payloads exactly where they need to go. A last-mile-delivery in space, so to speak.

Follow us on our social media channels to get more info than the "PR stuff" on our website We try to be as open and transparent as possible there. Rocket builders are often perceived as black boxes - and we would like to change that. So we take the community with us and share our journey. We are at the beginning of something big and are very happy to be able to contribute our part.

Edited September 1, 2021 by Rocket Factory Augsburg
Quoting

[RealKerbal3x]

Wow, didn't expect the company itself to show up on the forum! Looking forward to seeing what you can do guys!

[Elthy]

On 8/31/2021 at 5:57 AM, AngrybobH said:

Do you know anything else about these guys? Like timeline to orbit or if they are trying for reuse? I poked around on their site a bit and, while interesting, it was basically PR stuff, nothing much concrete. The impression I took from it was build 'em fast and cheap and dump 'em in the ocean when done. I don't suppose on a small enough scale that is all that bad.  It is nice to see more companies trying for the cheaper access to space.

They plan to launch 2022, but thats as optimistic as their aspired prices and payloads. There is lot to be sceptic about:

https://translate.google.com/translate?sl=de&tl=en&u=https://www.golem.de/news/deutsche-raumfahrt-rocket-factory-augsburg-macht-unglaubwuerdige-versprechen-2103-154734.html

Honestly i dont think a german rocket company has any chance. There is no political backing and no customers, who is supposed to buy their launches? Anyone commercial just goes with SpaceX if they are looking at the price while government payloads (of which there are almost none in the EU) are going with Arianespace.

[tater]

5 hours ago, Rocket Factory Augsburg said:

Yes, we build them fast and as inexpensive as possible (stainless steel), but we plan on reusing our first stage extensively. On the first flight(s) though, we focus on reaching orbit.

What mechanism for reuse? Parachute and a catch? Assuming steel is 2mm that puts the stage dry mass at maybe 2.5 tonnes, which seems within parachute capability.

[AngrybobH]

11 hours ago, Rocket Factory Augsburg said:

So we take the community with us and share our journey.

This is good news.

[SOXBLOX]

Wow. This thread just took a turn for the different.

Good luck, @Rocket Factory Augsburg! And, do you have a name for your rocket and upper stage?

(Now we just need to get Elon, Bezos, and Peter Beck on here...)

[JoeSchmuckatelli]

On 9/1/2021 at 2:59 AM, Rocket Factory Augsburg said:

Rocket builders are often perceived as black boxes - and we would like to change that. So we take the community with us

Don't be afraid to showcase failure.  Folks understand that space is hard.  SX has had success with this - take a page from their book and hang on! 

Viel Gluck! 

[Spacescifi]

On 9/1/2021 at 12:39 AM, Elthy said:

They plan to launch 2022, but thats as optimistic as their aspired prices and payloads. There is lot to be sceptic about:

https://translate.google.com/translate?sl=de&tl=en&u=https://www.golem.de/news/deutsche-raumfahrt-rocket-factory-augsburg-macht-unglaubwuerdige-versprechen-2103-154734.html

Honestly i dont think a german rocket company has any chance. There is no political backing and no customers, who is supposed to buy their launches? Anyone commercial just goes with SpaceX if they are looking at the price while government payloads (of which there are almost none in the EU) are going with Arianespace.

 

Even so... so long they stay funded... I believe they can definitely build and fly  their rockets successfully.

Why?

I have faith in German work ethic... which has international renown. They still have that after WWII, and they are capable of putting it to rocketry uses.

 

Afterall... remember where Russia and the USA found a lot of the technology  for the stuff they currently use?

 

Germany. Again. Never underestimate the Germans.

On 9/1/2021 at 6:56 PM, SOXBLOX said:

Wow. This thread just took a turn for the different.

Good luck, @Rocket Factory Augsburg! And, do you have a name for your rocket and upper stage?

(Now we just need to get Elon, Bezos, and Peter Beck on here...)

 

I reckon Elon probably knows... but he is busy with you know what LOL.

Bezos is also busy... in a different way.

Peter Bec-who the world is Peter Beck?!

Edited September 4, 2021 by Spacescifi

[OrdinaryKerman]

6 minutes ago, Spacescifi said:

Peter Bec-who the world is Peter Beck?!

is this a joke

[Starhelperdude]

sadly, Augsburg is pretty far away from me

we need baden-württembergische rocket companies

[tater]

https://www.youtube.com/watch?v=mcY8W9y0VaA

Livestream. For some reason they don't have embedding set.

 

Live now.

(I don't have time to watch it, but maybe someone wants to, lol)

[tater]

 

 

 

 

 

[Gargamel]

I wonder if they use random dice rolls to see which words of their tweets get turned into hashtags. 

[RyanRising]

What's the deal with 9-engined first stages? I see a lot of rocket companies trying to do that, and while it makes sense to only have to develop one engine with two variants rather than two, is 1/9 just a really convenient number for a second stage's ratio of thrust to the first?

[tater]

 

[cubinator]

On 4/13/2022 at 1:36 AM, RyanRising said:

What's the deal with 9-engined first stages? I see a lot of rocket companies trying to do that, and while it makes sense to only have to develop one engine with two variants rather than two, is 1/9 just a really convenient number for a second stage's ratio of thrust to the first?

I've heard that gimballing the outer engines inward in a configuration like that can give you a little bit of an aerospike effect without needing to build an aerospike.

[tater]

 

[JoeSchmuckatelli]

On 4/13/2022 at 2:36 AM, RyanRising said:

What's the deal with 9-engined first stages? I see a lot of rocket companies trying to do that, and while it makes sense to only have to develop one engine with two variants rather than two, is 1/9 just a really convenient number for a second stage's ratio of thrust to the first?

@sevenperforce recently said in another thread that having lots of small engines turns out to be more efficient than one large.  I'll let him explain better, or even if this is applicable to whether 9 is a special number or not.

[sevenperforce]

5 hours ago, JoeSchmuckatelli said:

On 4/13/2022 at 2:36 AM, RyanRising said:

What's the deal with 9-engined first stages? I see a lot of rocket companies trying to do that, and while it makes sense to only have to develop one engine with two variants rather than two, is 1/9 just a really convenient number for a second stage's ratio of thrust to the first?

@sevenperforce recently said in another thread that having lots of small engines turns out to be more efficient than one large.  I'll let him explain better, or even if this is applicable to whether 9 is a special number or not.

Well, the issue in the other thread was primarily combustion instability. Once you get into the world of really really big single-chamber engines like the Rocketdyne F-1, you're looking at combustion taking place inside a chamber significantly larger than a bathtub. Modern hydrodynamics modeling is significantly better than it was in the 1950s, but even so it's not perfect, and turbulent flow inside that gigantic chamber is going to mess with the ability to maintain a nice constant steady-state thrust situation. That's why the Russians built so many multi-chamber engines:

This is not four engines, but one engine with four chambers. There's a single turbopump feeding propellant to all four chambers, and all four chambers are throttled (down to an impressively deep 56%) at the same rate by throttling down the single turbopump. By keeping the thrust chambers physically smaller, you dramatically reduce combustion instability.

But while smaller startup launch companies DO have occasional issues with combustion instability, that isn't the real driver for using multiple first-stage engines. Those engines simply aren't large enough to encounter the endpoint problems that you get when you're working with something on the order of the F-1.

On 6/29/2022 at 4:28 PM, cubinator said:

I've heard that gimballing the outer engines inward in a configuration like that can give you a little bit of an aerospike effect without needing to build an aerospike.

AFAIK that's speculation from Tim Dodd; I don't know that it's at all accurate. Also I believe the outer engine bells on the Falcon 9 are already too close to each other to gimbal inward together. You might get a little higher pressure around the base of the center engine due to plume recirculation, reducing parasitic drag, but you're not going to get any sort of proper aerospike effect without an actual thrust surface against which to push.

I do think 1:9 is a pretty good ratio, overall.

Generally speaking, you need to have roughly equal ΔV on each stage for optimal efficiency.  If we take LEO as requiring ~9.5 km/s of total Δv (this will allow us to treat pressure drag as part of the total Δv, allowing us to use vacuum isp for our first stage), then the total propellant on the first stage as a percentage of gross liftoff weight is going to need to be around 79.5% for hypergols, 77.3% for kerolox, 73.6% for methalox, or 68.3% for hydrolox.

In modern aerospace, the dry mass of a stage is usually about 10-15% of the propellant it carries, although this varies based on propellant type. If we say it's about 13% just to put a number on it, then you can readily solve for the mass of the upper stage as a percentage of total gross liftoff weight: 10.2% for hypergols, 12.7% for kerolox, 16.8% for methalox, and 22.8% for hydrolox. 

If you're using common engines, your upper stage engine is going to have roughly 15% higher thrust compared to the first-stage engine thrust at sea level, and your first stage TWR needs to be about 20% higher than your upper stage. So the total thrust of your first stage as compared to your second stage is going to need to be around 13.5x for hypergols, 10.9x for kerolox, 8.2x for methalox, and 6.1x for hydrolox.

So for a hydrolox TSTO using common engines on the first and second stage, you could get away with using 5-7 sea level engines on the first stage and one vacuum-expanded engine on the second stage. However, most smallsat and startup launch companies don't wanna mess with hydrolox; it's expensive AF and it's difficult to handle, and the development costs for a hydrolox engine are much higher. Same with hypergols. In fact, I can't think of any hydrolox or hypergolic rockets which use common clustered engines. So smallsat and startup launchers are typically looking at kerolox and methalox, where an engine ratio of 8-11:1 is optimal.

Then why don't we see smallsat launchers with 8 methalox engines on the first stage or with 11 kerolox engines on the first stage? Well, circle packing becomes an issue. To reduce drag, you want your rocket to be as thin as possible, but you still need enough space on the back end to fit all the engines. The optimal arrangement of circles-within-a-circle is trivially symmetric at first:

However, once you go over nine engines, things start to get messy.

Optimal circle-in-circle packing with more than 9 circles is no longer trivially symmetric, which means you either waste valuable space on the back end of your booster or you end up with a thrust structure that is not axisymmetric. Plus, it helps with booster design if you can have a single engine at the center with an even number of evenly-spaced engines around it (so you can shut down opposite engines to maintain balanced thrust if you need to). The only circle-in-circle arrangements where those constraints are met by the optimal circle-in-circle packing are 1, 7, 9, and 19:

So yeah, that's why you're most often going to see 9 engines on the first stage of a launch vehicle that uses common engines.

Also note that 9 gives the central engine extra gimbal room which is especially nice if you want to recover your first stage propulsively.

Edited July 18, 2022 by sevenperforce

[JoeSchmuckatelli]

2 hours ago, sevenperforce said:

sevenperforce

Damn fine explication... Thanks! 

[jonminkun36]

looks amazing

[Spacescifi]

On 7/18/2022 at 3:59 PM, sevenperforce said:

Well, the issue in the other thread was primarily combustion instability. Once you get into the world of really really big single-chamber engines like the Rocketdyne F-1, you're looking at combustion taking place inside a chamber significantly larger than a bathtub. Modern hydrodynamics modeling is significantly better than it was in the 1950s, but even so it's not perfect, and turbulent flow inside that gigantic chamber is going to mess with the ability to maintain a nice constant steady-state thrust situation. That's why the Russians built so many multi-chamber engines:

This is not four engines, but one engine with four chambers. There's a single turbopump feeding propellant to all four chambers, and all four chambers are throttled (down to an impressively deep 56%) at the same rate by throttling down the single turbopump. By keeping the thrust chambers physically smaller, you dramatically reduce combustion instability.

But while smaller startup launch companies DO have occasional issues with combustion instability, that isn't the real driver for using multiple first-stage engines. Those engines simply aren't large enough to encounter the endpoint problems that you get when you're working with something on the order of the F-1.

AFAIK that's speculation from Tim Dodd; I don't know that it's at all accurate. Also I believe the outer engine bells on the Falcon 9 are already too close to each other to gimbal inward together. You might get a little higher pressure around the base of the center engine due to plume recirculation, reducing parasitic drag, but you're not going to get any sort of proper aerospike effect without an actual thrust surface against which to push.

I do think 1:9 is a pretty good ratio, overall.

Generally speaking, you need to have roughly equal ΔV on each stage for optimal efficiency.  If we take LEO as requiring ~9.5 km/s of total Δv (this will allow us to treat pressure drag as part of the total Δv, allowing us to use vacuum isp for our first stage), then the total propellant on the first stage as a percentage of gross liftoff weight is going to need to be around 79.5% for hypergols, 77.3% for kerolox, 73.6% for methalox, or 68.3% for hydrolox.

In modern aerospace, the dry mass of a stage is usually about 10-15% of the propellant it carries, although this varies based on propellant type. If we say it's about 13% just to put a number on it, then you can readily solve for the mass of the upper stage as a percentage of total gross liftoff weight: 10.2% for hypergols, 12.7% for kerolox, 16.8% for methalox, and 22.8% for hydrolox. 

If you're using common engines, your upper stage engine is going to have roughly 15% higher thrust compared to the first-stage engine thrust at sea level, and your first stage TWR needs to be about 20% higher than your upper stage. So the total thrust of your first stage as compared to your second stage is going to need to be around 13.5x for hypergols, 10.9x for kerolox, 8.2x for methalox, and 6.1x for hydrolox.

So for a hydrolox TSTO using common engines on the first and second stage, you could get away with using 5-7 sea level engines on the first stage and one vacuum-expanded engine on the second stage. However, most smallsat and startup launch companies don't wanna mess with hydrolox; it's expensive AF and it's difficult to handle, and the development costs for a hydrolox engine are much higher. Same with hypergols. In fact, I can't think of any hydrolox or hypergolic rockets which use common clustered engines. So smallsat and startup launchers are typically looking at kerolox and methalox, where an engine ratio of 8-11:1 is optimal.

Then why don't we see smallsat launchers with 8 methalox engines on the first stage or with 11 kerolox engines on the first stage? Well, circle packing becomes an issue. To reduce drag, you want your rocket to be as thin as possible, but you still need enough space on the back end to fit all the engines. The optimal arrangement of circles-within-a-circle is trivially symmetric at first:

However, once you go over nine engines, things start to get messy.

Optimal circle-in-circle packing with more than 9 circles is no longer trivially symmetric, which means you either waste valuable space on the back end of your booster or you end up with a thrust structure that is not axisymmetric. Plus, it helps with booster design if you can have a single engine at the center with an even number of evenly-spaced engines around it (so you can shut down opposite engines to maintain balanced thrust if you need to). The only circle-in-circle arrangements where those constraints are met by the optimal circle-in-circle packing are 1, 7, 9, and 19:

So yeah, that's why you're most often going to see 9 engines on the first stage of a launch vehicle that uses common engines.

Also note that 9 gives the central engine extra gimbal room which is especially nice if you want to recover your first stage propulsively.

 

Wow... you could write a book and get paidd for this type of thing you explain it so simply.

Just saying. You have a knack for this.

 

Do you work in aerospace or is it merely your leisure interest?