Suborbital refuelling

Brace yourself: in a few week, second round at The Space Review. God bless Jeff Foust, who is a gentleman. https://www.thespacereview.com/article/3875/1

It was a matter of bringing these three documents together, and re-do the math, to get a workable Excel spreadsheet.
Proof-check, kind of. I managed to do it. Brought Clapp and Goff together, re-did the maths. It worked.
https://arc.aiaa.org/doi/10.2514/6.2005-4188https://arc.aiaa.org/doi/10.2514/6.2004-3730http://www.ai.mit.edu/projects/im/magnus/bh/analog.html
Goff went too far with FLOC while Clapp did not got far enough with Black Horse. Wanted to explore a middleground: a 2 / 3 / 4 / 8 architecture, docking vs refueling.
 
For schemes like that, much more than just the math would have to work out, and I remain firmly skeptical on that...
 
Fair enough. On this, I can agree (as for Jim - when shaking your head, be careful about walls - you could hurt your brain)

I know perfectly who you are, both, and I respect your credentials.
 
Since when CREDENTIALS sounds like a threat ?

I'm not that kind of Internet arrogant dickhead.

If you wanna know, the whole thing is just an interesting intellectual exercise to me. I learned a lot of things in the process.

It is amusing to explore a RLV TSTO "terra incognita". Nothing more.

I know my classical RLV concepts. Also the theory.. Going into orbit is no picnic. Daunting numbers. Hard, unforgiving physics.
 
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Jets to replace Delta II solids I can see.
Jets on an orbiter or Starship to only aid in landing I can see.

Best to avoid the hypersonic murk and go all rocket/pop-up and save on the plumbing.
 
Hmmm... I would like to ask you two, please, don't do your usual "back and forth " on that thread... although I know which side I am... thank you...
 
Theory validated. I've redone Clapp and Goff numbers from the attached documents. See the spreadsheets. By this point suborbital docking seems to be much more interesting than refueling, basically FLOC has won against Black Horse.

Of course, practically is another matter, altogether (I know).
 

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  • Flock and Black Horse.xls -.xlsx
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Archibald said:
Theory validated. I've redone Clapp and Goff numbers from the attached documents. See the spreadsheet.

Of course, practically is another matter, altogether (I know).
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I am sorry... But I am just trying to understand the physics here...

What would be the difference of... let's say MUSTARD with 3 spaceplanes putting all the propellant into one last plane (while the emptied one bails out to land back on surface) and 3 of your SOR planes that do the suborbital refueling (1 for climb and 2 for refueling)?

I mean the details would differs quite a lot, yes, but in terms of rocket equation..? Isn't it basically doing the same thing? staging in a nut-shell but unlike space-X, all stages produces thrust til the moment of separation. I really don't understand the gain of SOR compared to the TSTO RLV with engines at the back.

Or that the benefit lies on the fact that each spaceplane now is more affordable gross mass that could take off from the airport rather than the launch site dedicated for the space launch?
 
Shuttle being a launch vehicle, had to be perhaps stronger than Buran. Tremendous loads

With VTOHL, TSTO rocket planes have to stand on their tails and land on their bellies as it were.

With refueling, you just need landing gear that can support the weight of the empty vehicle.

Is that enough to make a difference?
 
publiusr said:
Shuttle being a launch vehicle, had to be perhaps stronger than Buran. Tremendous loads

With VTOHL, TSTO rocket planes have to stand on their tails and land on their bellies as it were.

With refueling, you just need landing gear that can support the weight of the empty vehicle.

Is that enough to make a difference?
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Yes, so mainly the motivation of using sub orbital or subsonic refueling is to minimize the individual modules’ mass so that they can be operated on a normal runway! Of course, as a trade off, the difficulty of refueling during the flight.

Then one other point, if the suborbital refueling is a thing (not the subsonic refueling at 10-15 km), then I assume that the spacecraft (or spaceplane) wouldn’t benefit much from the air breathing engine, correct? The main pros of refueling is tweaking the mass fraction so just putting a good old rocket engine would do.

Maybe these planes need turbo fan for the maneuver when they land, but this could be glider like space shuttle I suppose..
 
The OK-92 pre-Buran could get away with turbojets.

On page 77 of Hendrixx & Vis book, those turbojets would have allowed OK-92 to fly under its own power--range 1,600 km at a cruise altitude of 3 km...increased to 3,000km by increasing fuel supply and using the solid fuel motor for take-off.

But that with Energiya doing all the work.

Archibald's concept keeps the rocket engine and tankage within the airframe, the polar opposite of Buran--closer to Rockwell's X-33 offering.

That makes it very sensitive to any add-ons. Maybe you could bolt on small jets for self ferry.

All this is why I pour over whatever the latest propellant or latest material can offer--in that new finds might give old designs new life.

The rocket planes of old? You saw no tiles on them.

Perhaps one day we will see sharp leading edges that won't melt.

On Europe's offerings:
https://www.thespacereview.com/article/5084/1
 
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publiusr said:
The OK-92 pre-Buran could get away with turbojets. On page 77 of Hendrixx & Vis book, those turbojets would have allowed OK-92 to fly under its own power--range 1,600 km at a cruise altitude of 3 km...increased to 3,000km by increasing fuel supply and using the solid fuel motor for take-off.

But that with Energiya doing all the work.

Archibald's concept keeps the rocket engine and tankage within the airframe, the polar opposite of Buran--closer to Rockwell's X-33 offering.

That makes it very sensitive to any add-ons. Maybe you could bolt on small jets for self ferry.

All this is why I pour over whatever the latest propellant or latest material can offer--in that new finds might give old designs new life. The rocket planes of old? You saw no tiles on them.
Perhaps one day we will see sharp leading edges that won't melt.
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How about the transpirational cooling techniques without any TPS? It seems couple of research groups demonstrated porous structure with or without pressurization to sip through water for the cooling using porous ceramic structure.

All in all, I agree to the point of the spaceplane with refueling, not really into FLOC which makes things to hard, but single refueling… it might worth it.

Then I come back to the point of propulsion, if suborbital spaceplane does not require air breathing engine but only the rocket propulsion, then would this mean that the Aerospike concept could also be appreciated for such concept?

Or do you think that even with the horizontal lift, the zoom climb is so rapid that the inefficiency at the high surrounding pressure would lead to negligible influence?
 
I have often wondered if the breadbox shuttle concept would be best for the linear aerospike---there was a recent "Eager Space" YouTube channel video that cast doubt on aerospikes.

A "pop-up" trajectory gets you up and out of the atmosphere as quickly as possible. Wings might be fine for first stages--but landing legs and chopsticks are all that's on people's minds.

With larger vehicles than what Clapp was thinking, it is more acceptable to just take a mass hit with VTOHL TSTOs with both stages being robust across the board. They, too, are empty upon landing on a runway.

Martin's FESTIP concept needs its own billionaire.

He would be the one to ask about different approaches, being no aerodynamicist myself.

I wonder if there is an A.I. that is pre-programmed with different launcher designs--a program that would send you a notification that a materials/propellant breakthrough has occurred that would make this or that lay-out finally doable.

All well above my pay grade.
 
publiusr said:
A "pop-up" trajectory gets you up and out of the atmosphere as quickly as possible. Wings might be fine for first stages--but landing legs and chopsticks are all that's on people's minds.
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But what about the vehicle that receives additional propellant and boosts up to the orbit? Wouldn’t that module also worthy of having a wing and a landing gear? I mean if the whole point of the new concept proposed in this thread is to use normal runway at the airport with horizontal lift off with restricted wet mass, both or all spacecraft must equipped with wings and the landing gears, right?

I think that if the suborbital refuel is the way to go, then just regular bell nozzle would be sufficient. For subsonic refueling, I anticipate a longer flight time at considerable pressure which give a little reasoning behind using the Aerospike… nevertheless, putting air breathing engine with the rocket seems to be a overkill and degrade the performance where the key concept of the system is refueling..

In this sense, I think that two approaches from the recent spaceplane companies, dawn and Polaris has similar concept in mind. They both developing space planes and also the refueling system, rapid zoom climb with bell type nozzle for dawn with zero g refueling instrument under development whereas Polaris working on the autonomous refueling drone with Aerospike engine. How do you think?
 
publiusr said:
The OK-92 pre-Buran could get away with turbojets.
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It is not a validated design. It was never built and flew. Just another paper project.
publiusr said:
All this is why I pour over whatever the latest propellant or latest material can offer--in that new finds might give old designs new life.
Click to expand...
A useless endeavor. Neither can help enough with chemical propellants. Can't change physics and earth's gravity. Old designs will remain dead
publiusr said:
The rocket planes of old? You saw no tiles on them.
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Because they assumed unobtainium for TPS
publiusr said:
Perhaps one day we will see sharp leading edges that won't melt.
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No, not with just material protection.

there is no hidden elements. materials or fluids that are going to make a radical change. It will have to be a new energy source to change things.
 
Byeman said:
A useless endeavor. Neither can help enough with chemical propellants. Can't change physics and earth's gravity. Old designs will remain dead
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The Soviet try similar with Spiral 50/50 and failed
unable to build the Jet engines to bring carrier aircraft to Mach 6
while Glushko came up with more and more toxic and dangerous Propellants for Rocket stage
to compensate the Carrier lack of Mach 6, until Military say: No Glushko, NO, sit...
 
@csm9420 I'll answer later. When things have cooled down. It is mostly explained inside the spreasheets, see attached documents.
 

Attachments

  • FLOC variations.xlsx
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  • Flock and Black Horse.xls -.xlsx
    1.7 MB · Views: 3
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