Delta Clipper and other single-stage missiles impossible?

[OOM]

You may think what you want, but I was going to challenge, it would seem, professional engineers.
There is such a question ... at the expense of single-stage missiles like DC-X.
which I consider impossible to do because of the usual low performance of chemical rocket engines, where the power of one stage is simply not enough to gain 8 km/s and enter the Earth’s orbit.

Yes, in our game the sizes of the planets (like everything else) are reduced. BUT -
The characteristics of chemical rocket engines remained the same (impulse of 300-465, thrust and mass according to size)

The best result that can be achieved with a chemical rocket engine is 4000-4500 m / s.
Question: how could this DC-X with a fuel mass of 18 tons enter the Earth’s orbit?

It turns out that Delta Clipper and other "single-stage" missiles are initially IMPOSSIBLE, unless, of course, this is KSP, where it takes only 2250 m / s to reach the orbit.
Or explain to me once again how a chemical (single-stage) rocket engine can have a delta of 8000 m / s (this is the performance of the entire nuclear engine)?

Plus, as proof - at the moment there is not a single one-stage chemical rocket ...
This is because it is impossible to do, otherwise we would have long had such promising missiles, where after the flight you need to pay only for refueling and maintenance.
Instead, we simply create multi-stage missiles and successfully destroy the work of engineers (and resources in the form of metals) during the flight.
And it’s good that in some missiles the first stage can be returned ...

[sh1pman]

23 minutes ago, OOM said:

The best result that can be achieved with a chemical rocket engine is 4000-4500 m / s.

Exhaust velocity and delta-V are not the same thing.

23 minutes ago, OOM said:

how could this DC-X with a fuel mass of 18 tons enter the Earth’s orbit?

Why do you think DC-X was ever intended to reach orbit?

31 minutes ago, OOM said:

gain 8 km/s and enter the Earth’s orbit.

You actually need about 9.5 km/s to reach LEO, because of gravity and atmospheric drag.

34 minutes ago, OOM said:

Or explain to me once again how a chemical (single-stage) rocket engine can have a delta of 8000 m / s (this is the performance of the entire nuclear engine)?

Again, you're mixing up delta-V and exhaust velocity.

34 minutes ago, OOM said:

Plus, as proof - at the moment there is not a single one-stage chemical rocket ...

Because it's impractical. Multi-stage brings more payload to orbit.

I suggest you study Tsiolkovsky rocket equation:

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

[OOM]

21 minutes ago, sh1pman said:

Exhaust velocity and delta-V are not the same thing.

Why do you think DC-X was ever intended to reach orbit?

You actually need about 9.5 km/s to reach LEO, because of gravity and atmospheric drag.

Again, you're mixing up delta-V and exhaust velocity.

Because it's impractical. Multi-stage brings more payload to orbit.

I suggest you study Tsiolkovsky rocket equation:

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

1-4: Most likely a problem with the translator. I do not know how to get him to write correctly.
I think the clue is clear about what the speech is about.
2. Yes, and DC-X and Skylon and Venture Star - all this should be a one-stage reusable spacecraft for delivering goods into orbit.
3. I wrote this as the minimum limit that will be reached. Plus, this need for speed hammer the last nail into the coffin of a single-stage rocket.
5. But at what cost? Multistage rockets are just a one-time toy, dear. This is how to change the car after each trip.
6. How does this help me? I wanted to spit on these equations in this case. Because there is no sense from them if in practice it is impossible to do.

I do not see a solution to the problem here.
This is either: replacing conventional chemical engines with nuclear engines with a pulse of at least 800.
But nuclear engines alone are bad as first-stage engines.

Thus, only one option remains - a two-stage reusable spacecraft such as the Saenger.

 

Edited October 15, 2019 by OOM

[tater]

It is a matter of getting a high enough I_sp, and a low enough dry mass. Yes, this is very difficult, but not impossible.

A 1270 ton (wet) craft like the SpaceX Starship, with an average I_sp of 350, and a dry mass of 70 tons (much less massive than SS) has 9947 m/s of dv---enough to get to orbit, and indeed enough to get to orbit with around 9 tons of payload.

If the goal is not recovery of stage 2, SSTOs with payload is possible.

[Wjolcz]

Isn't F9's first stage SSTO? It's not like it's impossible. It's just not practical.

[sh1pman]

Just now, OOM said:

6. How does this help me? I wanted to spit on these equations in this case. Because there is no sense from them if in practice it is impossible to do.

Can't help you if you don't want to learn. If you look at the equation, you'll understand where you are wrong. Because you are wrong, and single stage to orbit designs with chemical engines are possible. Falcon 9 first stage can almost reach orbit.

5 minutes ago, OOM said:

2. Yes, and DC-X and Skylon and Venture Star - all this should be a one-stage reusable spacecraft for delivering goods into orbit.

But not DC-X. It was a prototype to study launch and powered landing. Actual SSTO would have enough delta-V to reach orbit and return. 

10 minutes ago, OOM said:

But at what cost? Multistage rockets are just a one-time toy, dear. This is how to change the car after each trip.

Two-stage reusable designs are possible and one of them is being developed right now.

Also, what is this "dear"? I'm not your pal. 

[OOM]

6 minutes ago, sh1pman said:

Can't help you if you don't want to learn. If you look at the equation, you'll understand where you are wrong. Because you are wrong, and single stage to orbit designs with chemical engines are possible. Falcon 9 first stage can almost reach orbit.

But not DC-X. It was a prototype to study launch and powered landing. Actual SSTO would have enough delta-V to reach orbit and return. 

Two-stage reusable designs are possible and one of them is being developed right now.

Also, what is this "dear"? I'm not your pal. 

1. I do not need to be taught. 
2. I have no doubt that you can make a huge and useless single-stage rocket. But the question is, what is the benefit of such a rocket?
3. I repeat once again - the problem of the translator. I try my best, but the translator SOMETIMES writes whatever horrible. Not at all what I wanted to say.

Edited October 15, 2019 by OOM

[tater]

Just now, OOM said:

2. I have no doubt that you can make a huge and useless single-stage rocket. But the question is, what is the benefit of such a rocket?

In the cases of the 2 you mentioned, Delta Clipper (not the -X test vehicle, but the real thing, had they made it) or Venture Star, the benefit was that the SSTO was to be reused. If you can reuse the vehicle, then it has huge value, as the cost is mostly just the propellants.

Two Stage To Orbit, reusable, makes things easier to do, and increases the payload mass fraction.

Just now, OOM said:

3. I repeat once again - the problem of the translator. I try my best, but the translator SOMETIMES writes whatever horrible. Not at all what I wanted to say.

It's working well enough, we just have to suffer as we all do with "autocorrect" on our cell phones (it will sometimes result in comedy).

[magnemoe]

7 minutes ago, Wjolcz said:

Isn't F9's first stage SSTO? It's not like it's impossible. It's just not practical.

many first stages would be SSTO if given just an light weight fairing and not an second stage. However they would not be able to carry much payload. and you would wast the stage, better to use an smaller rocket. 

The challenging for making an reusable SSTO is huge. First you need high enough TWR and the engines cut into you payload, then you need to be able to reenter and land. 
Even if you manage you have an good chance of making an hangar queen because you have to push the technology to the limit. 
That you earn is the benefit of not having to mate the stages. 

Two stage fully reusable is much easier. most of the rocket just go suborbital so much less heat issues here as seen on falcon 9 first stage. 
Second stage is smaller and lighter, far fewer engines and smaller tanks. Less area to heat shield and an lower weight makes this more manageable, landing an small rocket is also easier. 

Remember that every kg into the upper stage is one kg less payload capacity. Every kg on lower stage only cost you 2-300 gram payload. 
 

[sh1pman]

1 minute ago, OOM said:

2. I have no doubt that you can make a huge and useless single-stage rocket. But the question is, what is the benefit of such a rocket?

First you said it was impossible, now you're saying it's impractical. Which one is it?

2 minutes ago, OOM said:

1. I do not need to be taught. 

Well, the answer for your first question (was it even a question?) is in that equation. You can have a SSTO rocket with a delta-V of 9500+m/s. With chemical engines. Nothing impossible about it, just impractical. 

[Wjolcz]

4 minutes ago, magnemoe said:

hangar queen

I really like that phrase.

Edited October 15, 2019 by Wjolcz

[OOM]

5 minutes ago, sh1pman said:

First you said it was impossible, now you're saying it's impractical. Which one is it?

Well, the answer for your first question (was it even a question?) is in that equation. You can have a SSTO rocket with a delta-V of 9500+m/s. With chemical engines. Nothing impossible about it, just impractical. 

And in the last post, I mentioned two-stage reusable missiles. This is perhaps the only solution to the problems.
Of course, I would like to discuss more interplanetary and interstellar flights of the future (to which I have the greatest interest), BUT -
To do this, you need to have a stable and inexpensive device for delivering people and goods into orbit.
What do we have?
And we have the P-7 and the Soyuz since the 1960s  Perhaps this is not a very good condition, and it cannot last long.
Perhaps something like this is an adequate solution to the problem.
https://en.wikipedia.org/wiki/Saenger_(spacecraft)

Edited October 15, 2019 by OOM

[sh1pman]

Just now, OOM said:

And in the last post, I mentioned two-stage reusable missiles. This is perhaps the only solution to the problems.

Most likely, but Skylon might also work. If they get that engine done.

1 minute ago, OOM said:

To do this, you need to have a stable and inexpensive device for delivering people and goods into orbit.

True.

2 minutes ago, OOM said:

And we have the P-7 and the Union since the 1960s  Perhaps this is not a very good condition, and it cannot last long.

You mean Soyuz? There are new versions coming up, some with reusable first stage even. Maybe Roscosmos will see the benefit of full reuse eventually (hopefully). But not with the current director, for sure.

[OOM]

20 minutes ago, sh1pman said:

Most likely, but Skylon might also work. If they get that engine done.

True.

You mean Soyuz? There are new versions coming up, some with reusable first stage even. Maybe Roscosmos will see the benefit of full reuse eventually (hopefully). But not with the current director, for sure.

1. I really hope for it.
3. It is useless 
Moreover, it is still expensive. Plus the inability to transport large loads ...
I wish the legendary space shuttle to be returned.
Creating a new fuel tank and filling it with fuel is nothing compared to creating a completely new rocket with engines, electronics and more.
Space shuttle .... we had such a wonderful device before.
And now, in the days of the iPhone 11, we have lost almost all the possibilities of high-quality space flights 

 

Edited October 15, 2019 by OOM

[tater]

2 hours ago, OOM said:

1. I really hope for it.
3. It is useless 
Moreover, it is still expensive. Plus the inability to transport large loads ...
I wish the legendary space shuttle to be returned.
Creating a new fuel tank and filling it with fuel is nothing compared to creating a completely new rocket with engines, electronics and more.
Space shuttle .... we had such a wonderful device before.
And now, in the days of the iPhone 11, we have lost almost all the possibilities of high-quality space flights 

Space Shuttle was an amazing vehicle, but much was either thrown away with each use, or required a great deal of work after return for it to be ready for another flight.

It was also very, very expensive per flight.

What we need is inexpensive access to space.

Currently we have:

Falcon 9 and Falcon Heavy (stage 1 (FH) cores landing, below).

 

Soon we will have:

New Glenn

 

And even Starship:

https://www.spacex.com/sites/spacex/files/01_starshipspinvertwide_2mbs_1.mp4

[OOM]

1 hour ago, tater said:

Space Shuttle was an amazing vehicle, but much was either thrown away with each use, or required a great deal of work after return for it to be ready for another flight.

It was also very, very expensive per flight.

What we need is inexpensive access to space.

Currently we have:

Falcon 9 and Falcon Heavy (stage 1 (FH) cores landing, below).

 

Soon we will have:

New Glenn

 

And even Starship:

https://www.spacex.com/sites/spacex/files/01_starshipspinvertwide_2mbs_1.mp4

These wonderful rockets are the solution to the problems with single-stage rockets.
As I said earlier, everything, like VentureStar, HOTOL and others, is a stillborn project.

Since they have no problems with the possibility of reuse, the last thing that remains, besides maintenance, is fuel.
These rockets use methane.
Find a Cheap Methane Source ...
Theoretically, this can be done using large bioreactors, and you can get biogas, which then needs to be cleaned. I do not know the price of fuel in such a volume, and I do not know whether it will be more profitable than regular methane.
But the "methane" greenhouses may well be created by SpaceX ... and besides getting methane, do waste sales as fertilizers.

Edited October 15, 2019 by OOM

[tater]

If SpaceX can figure out second stage reusability (rapid, cheap reuse, not the large refub of Shuttle, which did it first, obviously), then there is a chance they (or someone else) could then make an SSTO vehicle similar to Starship. The payload would be small---but this works very well for a crew vehicle where the cargo is a mere several hundred kg of humans, and some life support.

[kerbiloid]

4 hours ago, OOM said:

Creating a new fuel tank and filling it with fuel is nothing compared to creating a completely new rocket with engines, electronics and more.

Then you want a reusable instrumentation + propulsion unit, not the reusable rocket. As any rocket tank is like the shuttle's one, but smaller.

4 hours ago, OOM said:

And now, in the days of the iPhone 11, we have lost almost all the possibilities of high-quality space flights

I would presume that orbital station + 2..3 hours short flight in Soyuz is much more comfortable that a Space Shuttle fortnight journey.
They have even Espresso machine onboard.

45 minutes ago, OOM said:

Find a Cheap Methane Source ...

Holes in ground. Gas flows from there.

43 minutes ago, tater said:

If SpaceX can figure out second stage reusability (rapid, cheap reuse, not the large refub of Shuttle, which did it first, obviously), then there is a chance they (or someone else) could then make an SSTO vehicle similar to Starship. The payload would be small---but this works very well for a crew vehicle where the cargo is a mere several hundred kg of humans, and some life support.

Greta hears you...

[Thor Wotansen]

1 hour ago, OOM said:

Find a Cheap Methane Source ...

I believe SpaceX is eventually planning to have a ISRU unit using the Sabatier process to make their own methane out of a bit of hydrogen and CO2 from the atmosphere.  One benefit of this is that it creates a decent amount of excess energy that can be harnessed to do things like make electricity.  I wouldn't be surprised if SpaceX was carbon neutral by 2030.

[magnemoe]

9 minutes ago, Thor Wotansen said:

I believe SpaceX is eventually planning to have a ISRU unit using the Sabatier process to make their own methane out of a bit of hydrogen and CO2 from the atmosphere.  One benefit of this is that it creates a decent amount of excess energy that can be harnessed to do things like make electricity.  I wouldn't be surprised if SpaceX was carbon neutral by 2030.

That would be KSP level ISRU as in you get free energy. 
In real world you have to use much more energy generating this methane than the energy in the methane. 
This work at Mars as the cost of one liter of methane on Mars would cost as much as one liter of good cognac even if skipped in by starship. 
Earth don't work like that, if you want to be carbon neutral you buy methane or LNG and sell clean power to compensate. 

Add that Mars atmosphere is thin but its mostly co2, on earth its .4% who would complicate any process working on atmospheric co2 a lot. 
In short any plan to capture co2 from the atmosphere is an scam, why not capture at the exhaust from an power plant or simply don't use it.  
And no testing an Mars ISRU system on earth would be useless, test in in an low pressure mostly co2 atmosphere. 


 

[sh1pman]

38 minutes ago, magnemoe said:

any plan to capture co2 from the atmosphere is an scam

Therefore, all trees are scammers!

[Guest]

Actually, methane from atmospheric CO2 makes sense as an energy storage. Nuclear power is great and ecological, but nuclear reactors are heavy and bulky. Batteries have their problems, it's better to turn CO2 into methane (or higher hydrocarbons) using nuclear energy, then burn methane back to CO2. In portable applications, energy density is important, and chemical energy is hard to beat in that regard. As long as your initial energy production doesn't come from carbon, this method is perfectly valid. 

This is also a good way to "redistribute" nuclear energy to countries which shouldn't be trusted with actual refined uranium, or just plain can't afford the expense. Ideally, nuclear powers would switch to an all-nuclear (backed by renewables on a local basis) energy, and produce methane for portable use and to sell to poorer countries. This would not shut down coal and oil use, but it would be a good start.

[Thor Wotansen]

1 hour ago, magnemoe said:

That would be KSP level ISRU as in you get free energy. 
In real world you have to use much more energy generating this methane than the energy in the methane. 
This work at Mars as the cost of one liter of methane on Mars would cost as much as one liter of good cognac even if skipped in by starship. 
Earth don't work like that, if you want to be carbon neutral you buy methane or LNG and sell clean power to compensate. 

Add that Mars atmosphere is thin but its mostly co2, on earth its .4% who would complicate any process working on atmospheric co2 a lot. 
In short any plan to capture co2 from the atmosphere is an scam, why not capture at the exhaust from an power plant or simply don't use it.  
And no testing an Mars ISRU system on earth would be useless, test in in an low pressure mostly co2 atmosphere.

From Wikipedia:

Quote

The Sabatier reaction or Sabatier process was discovered by the French chemist Paul Sabatier and Senderens in 1897. It involves the reaction of hydrogen with carbon dioxide at elevated temperatures (optimally 300–400 °C) and pressures in the presence of a nickel catalyst to produce methane and water. Optionally, ruthenium on alumina (aluminium oxide) makes a more efficient catalyst. It is described by the following exothermic reaction.^[1][2]

CO2+4H2→pressure400 ∘CCH4+2H2O{\displaystyle {\ce {CO2{}+4H2->[{} \atop 400\ ^{\circ }{\ce {C}}][{\ce {pressure}}]CH4{}+2H2O}}} ∆H = −165.0 kJ/mol

 

The reaction is exothermic, meaning it produces heat.  This means you can remove heat while still maintaining the 300-400 °C needed for the optimal reaction.  Heat can be used for all sorts of useful things, like powering a sterling engine to run a generator to electrolize water for hydrogen, or liquefy air to extract pure CO2, with a cryocooler.  So yes, as long as you don't let any methane escape into the atmosphere, you can have some of your lunch for free.

 

[sh1pman]

40 minutes ago, Dragon01 said:

Actually, methane from atmospheric CO2 makes sense as an energy storage. Nuclear power is great and ecological, but nuclear reactors are heavy and bulky. Batteries have their problems, it's better to turn CO2 into methane (or higher hydrocarbons) using nuclear energy, then burn methane back to CO2. In portable applications, energy density is important, and chemical energy is hard to beat in that regard. As long as your initial energy production doesn't come from carbon, this method is perfectly valid. 

This is also a good way to "redistribute" nuclear energy to countries which shouldn't be trusted with actual refined uranium, or just plain can't afford the expense. Ideally, nuclear powers would switch to an all-nuclear (backed by renewables on a local basis) energy, and produce methane for portable use and to sell to poorer countries. This would not shut down coal and oil use, but it would be a good start.

You need hydrogen to turn CO2 into CH4, and the best total efficiency of electrolysis + Sabatier is around 50%. Meaning that 50% of energy is released as waste heat. Then, you need to burn that methane again to generate electricity at a natural gas power plant, and their efficiency is at best 40-60%. So by going through this conversion cycle you lose about 3/4 of your initial electrical energy. Better to just buy a nuclear power plant from Russia. They don’t require enriched uranium.

[Guest]

Except a nuclear power plant is expensive and uranium is also expensive. Waste heat doesn't really matter on Earth, CO2 is causing the sun to heat the planet up much faster than directly dumping heat into it would.