Relativity Space (future launch provider)

[sevenperforce]

5 minutes ago, SpaceFace545 said:

But unlike starship, bfr psychically couldn’t flip in the thicker parts of the atmosphere. It had enough control for the upper atmosphere but that’s it. 

Starship physically can't flip in the thick parts of the atmosphere; that's why it has to use engine gimbal. The ITS would have had an easier time doing an aerodynamic flip because it didn't have the heavy header tank in the nose.

Just now, SpaceFace545 said:

I think In the lower atmosphere BFR would turn into a dart 

It would have been more likely to go tail-first. That's where all the heavy stuff (including the header tanks) would have been.

It would have been a chaotic tail-first, though, so it would need to fire up the engines for control just after the flip initiated.

I'm a little confused by only having a single Aeon Vac engine on the upper stage, though. Terran 1 uses nine Aeon 1 engines on the first stage and a single Aeon Vac on the second stage, while the graphics say that Terran R uses seven Aeon R engines on its booster and a single Aeon Vac on the second stage. The Aeon Vac only produces 126 kN which hardly seems anywhere near sufficient for pushing 20 tonnes into LEO. For reference the Merlin 1DVac is around 900 kN IIRC.

Plus, they can't use the standard Aeon Vac because its radiative nozzle won't work inside the engine bay. Perhaps they will rig up the Aeon Vac with an extensible and retractable nozzle like an RL-10 to allow it to do a landing burn? Maybe they will add a couple of Aeon 1 engines on the second stage to increase thrust at separation and then use the Aeon Vac by itself for the final push to orbit?

[RCgothic]

If Terran 1 uses 9 Aeon1 engines and Terran R uses 7 AeonR engines then AeonR must be much more powerful than Aeon1 and it's probably an AeonRVac not an Aeon1Vac on the 2nd stage.

Edited June 9, 2021 by RCgothic

[Spaceman.Spiff]

1 hour ago, sevenperforce said:

I'm a little confused by only having a single Aeon Vac engine on the upper stage, though. Terran 1 uses nine Aeon 1 engines on the first stage and a single Aeon Vac on the second stage, while the graphics say that Terran R uses seven Aeon R engines on its booster and a single Aeon Vac on the second stage. The Aeon Vac only produces 126 kN which hardly seems anywhere near sufficient for pushing 20 tonnes into LEO. For reference the Merlin 1DVac is around 900 kN IIRC.

Maybe they actually plan to use an Aeon 1R Vac?

[sevenperforce]

29 minutes ago, RCgothic said:

If Terrain 1 uses 9 Aeon1 engines and Terran R uses 7 AeonR engines then AeonR must be much more powerful than Aeon 1 and it's probably an AeonRVac not an Aeon1Vac on the 2nd stage.

That's what I thought, too, but apparently not:

Relativity has completed hundreds of tests on its Aeon 1 engines that will power Terran 1 – but Terran R will feature a “new engine called Aeon R” that the company has begun developing, Ellis said.

“We’ve also tested the engine for the upper stage,” Ellis said. “It’s a copper chamber engine ... and it’s actually now the same engine on the upper stage of Terran R as on Terran 1.”

The article showed this image, which it said was the upgraded Aeon Vac firing without its nozzle extension.

Spoiler

That said, this upgraded Aeon Vac would either (a) need to be fully regeneratively cooled like the Raptor Vac or (b) have an extensible (and retractable) nozzle like the RL-10B-2. The latter option would save on space in the interstage/engine bay and it would probably save on weight too.

I wonder how they'll keep it from tumbling during re-entry. Those strakes are nice and all but with a very fluffy forward payload bay I'd expect it to tend to go tail-first. Maybe the strakes are designed to keep it passively aerodynamically stable?

The Aeon 1 is a methalox gas generator. I don't see any exhaust on any of the firing videos, though, so it must use partial exhaust film cooling or something. I don't think there's any word yet on what cycle they'll use for the Aeon R. With 3D printing and methalox they could do some fun things with a dual bleed expander cycle engine. Closed expander cycles are limited to about 150 kN but a bleed expander cycle can get up to 270 kN and a GG-augmented bleed expander cycle could go even higher. 

[RCgothic]

Huh. Aeon1Vac surely isn't remotely powerful enough for TerranR. AeonRVac for Terran1 technically doesn't contradict that statement?

For AeonR: with a payload 2/15ths to 1/5th a starship the TerranR must weigh ballpark 670 to 1000t. That's roughly at least 95t (900kN) per engine. With a TWR 1.5, that'd be 1.4MN.

Not a small engine?

[SOXBLOX]

It really seems like something's not adding up here... Hopefully we get to see more information.

[SpaceFace545]

2 minutes ago, SOXBLOX said:

more information.

Yeah, the thing doesn't even have a heat shield yet.

[Spaceman.Spiff]

4 hours ago, sevenperforce said:

The Aeon 1 is a methalox gas generator. I don't see any exhaust on any of the firing videos, though, so it must use partial exhaust film cooling or something. I don't think there's any word yet on what cycle they'll use for the Aeon R. With 3D printing and methalox they could do some fun things with a dual bleed expander cycle engine. Closed expander cycles are limited to about 150 kN but a bleed expander cycle can get up to 270 kN and a GG-augmented bleed expander cycle could go even higher. 

Since they’re using methane anyway, I wonder if the DEAN would fit the use case. 
(Dual Expander Aerospike Nozzle(?))

[SpaceFace545]

4 minutes ago, Spaceman.Spiff said:

Since they’re using methane anyway, I wonder if the DEAN would fit the use case. 
(Dual Expander Aerospike Nozzle(?))

you could but aerospikes aren't that great at gimbaling.

[Spaceman.Spiff]

12 minutes ago, SpaceFace545 said:

you could but aerospikes aren't that great at gimbaling.

You use differential thrust. 

[tater]

29 minutes ago, SpaceFace545 said:

Yeah, the thing doesn't even have a heat shield yet.

Well, it doesn't actually exist, so...

 

[SpaceFace545]

1 hour ago, tater said:

Well, it doesn't actually exist, so...

 

Exactly, at this point it’s just a cgi render, same with their first rocket as well.

[Spaceman.Spiff]

2 minutes ago, SpaceFace545 said:

Exactly, at this point it’s just a cgi render, same with their first rocket as well.

Not really. They’ve made a lot of hardware for Terran 1.  
Engines, full second stage, at least a first stage test tank, as well as the whole robotic 3D priming setup. 
 

[tater]

5 minutes ago, SpaceFace545 said:

Exactly, at this point it’s just a cgi render, same with their first rocket as well.

No, they actually have engines, and are planning to launch this year.

Tank:

 

 

 

Engine full duration test:

 

 

 

Google exists, you know.

[SpaceFace545]

5 minutes ago, tater said:

No, they actually have engines, and are planning to launch this year.

Tank:

 

 

 

Engine full duration test:

 

 

 

Google exists, you know.

Huh, that’s really impressive, you don’t hear much of them in the news. Do you think 3D printing a rocket is actually beneficial or just a buzzword?

[Spaceman.Spiff]

14 minutes ago, SpaceFace545 said:

Huh, that’s really impressive, you don’t hear much of them in the news. Do you think 3D printing a rocket is actually beneficial or just a buzzword?

I think it has tangible benefits. Relativity says they can print a rocket in 60 days. Plus it’s probably good for structural integrity because there are no welds to worry about. 

Spoiler

Although it’s sort of all welds in a way. 

 

Also it makes sense that it would reduce production costs because they don’t need to have people building the rocket. 
Sounds like engine complexity is reduced by 3D printing as well. 

Edited June 10, 2021 by Spaceman.Spiff

[tater]

12 minutes ago, SpaceFace545 said:

Huh, that’s really impressive, you don’t hear much of them in the news. Do you think 3D printing a rocket is actually beneficial or just a buzzword?

Dunno, guess we see in the next few months.

Presumably they have tested tanks, and they are strong enough, though their initial use case was to make them cheap by reduced labor—expendable vehicles. Reuse means maybe they need stronger materials. It's an interesting idea, and if you watch their youtube vids they are very much "colonize Mars" people who think they need labor saving devices to make stuff on Mars, even to the point of being able to build rockets.

Starship is partially "3D printed"—but the build stock is 1.83m tall sheets of 4mm steel, lol. Actually, at this point all rockets made of metal are built robotically. Unsure what counts as 3d printed, does the stock have to completely melt as part of the process to be "3d printed?"

 

 

(I remember watching some selective laser sintering at Sandia a rather long time ago, and the build stock in that case is a powder bed (sorta like resin printers, but the laser melts the metal powder). Maybe their printers deliver powder and melt at the same time (vs wire stock).)

[sevenperforce]

I am very interested in whatever cycle they’re going to come up with for the Aero R. If I was going to design a methalox engine of that thrust level from scratch, I would go with a dual split bleed expander augmented by a gas generator, but with the gas generator downstream of the bleed with dual heat exchangers. That way you extract ALL the heat from the chamber first, THEN extract precisely as much additional heat as you need from the gas generator, but you are still able to keep your oxidizer and fuel pumps completely separate and you don’t need any nasty shaft seals. The gas generator empties into the nozzle so it doesn’t need high pressure, and it’s very accommodating of changing mixture ratios so you have a lot of variability during flight. 

[magnemoe]

On 6/10/2021 at 6:10 AM, Spaceman.Spiff said:

I think it has tangible benefits. Relativity says they can print a rocket in 60 days. Plus it’s probably good for structural integrity because there are no welds to worry about. 

  Hide contents

Although it’s sort of all welds in a way. 

 

Also it makes sense that it would reduce production costs because they don’t need to have people building the rocket. 
Sounds like engine complexity is reduced by 3D printing as well. 

Yes but 3d printed metal does not have the strength of  rolled metal who work harden it. 
They can get tessellation on the cheap but it don't look like they do that. 

For engines its another matter since they are are complex, at least the impeller and the nozzle.  Engine mounts could benefit from printing. 

 

[magnemoe]

On 6/8/2021 at 3:27 PM, tater said:

 

 

Someone trying to be a "fast follower."

 

I'm interested in what happens with them, and maybe they can help drive costs down. As I have said in at least a couple other threads, the total launch market is not huge, so the only way for this to be a growth industry vs fighting for scraps is if costs drop tot he point it creates entirely new businesses in space. I'm honestly unsure how possible that is, but step one is to have 2 providers capable of competing on cost to drive prices far, far lower.

This is 20t to LEO, 100% reuse.

Its interesting, starship is way overkill for most missions, pizza vans are not semi trucks for an reason. 
And yes its an limited market now. 
On the other hand things gone change, just one example for the ISS replacement  NASA want to buy in on an commercial space station. 
Yes they want to add lab modules to it but they don't want anything to do with station maintenance or hotel services. 
They assume that most of the station service will be commercial services and tourism. 
The problem with IIS is that they  spend  way more time maintaining it than doing science, dragon with 4 crew helps a lot. 
With starship you might do manned missions cheaper than robotic landers and you have two rovers and an drill rig. 

[Mad Rocket Scientist]

One interesting possibility here is stretching the tanks or payload bay as necessary for the mission, a la KSP procedural tanks. That seems to be undermined by full reusability though.

[GuessingEveryDay]

Ooh? What's this?

Didn't know they were printing the cooling tubes directly into the engines.

[tater]

 

Aiming to launch in early 2022.

[Beccab]

 

[tater]