A Low Cost, All European, Manned Launcher.

[RGClark]

[This is in reference to an argument attached below that the Ariane 5 core stage

can be SSTO with 3 Vulcain engines.]

 

The most important accomplishment of SpaceX may turn out to be they showed in

such stark terms the savings possible when launchers are privately financed:

 

SpaceX Might Be Able To Teach NASA A Lesson.

May 23, 2011

By Frank Morring, Jr.

Washington

“I think one would want to understand in some detail . . . why would it be

between four and 10 times more expensive for NASA to do this, especially at a

time when one of the issues facing NASA is how to develop the heavy-lift

launch vehicle within the budget profile that the committee has given it,”

Chyba says.

He cites an analysis contained in NASA’s report to Congress on the market for

commercial crew and cargo services to LEO that found it would cost NASA

between $1.7 billion and $4 billion to do the same Falcon-9 development that

cost SpaceX $390 million. In its analysis, which contained no estimates for

the future cost of commercial transportation services to the International

Space Station (ISS) beyond those already under contract, NASA says it had

“verified” those SpaceX cost figures.

For comparison, agency experts used the NASA-Air Force Cost Model—“a

parametric cost-estimating tool with a historical database of over 130 NASA

and Air Force spaceflight hardware projects”—to generate estimates of what it

would cost the civil space agency to match the SpaceX accomplishment. Using

the “traditional NASA approach,” the agency analysts found the cost would be

$4 billion. That would drop to $1.7 billion with different assumptions

representative of “a more commercial development approach,” NASA says.

http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/awst/2011/05/23/AW_05_23_2011_p36-324881.xml

 

The SpaceX experience of developing a launcher in the Falcon 9 at 1/10th the

cost of a government financed one also holds for the crew capsule development

costs since the Dragon capsule cost about $300 million to develop while the

Orion costs several billion and still counting. So it can't be said this cost

saving is just due to the Falcon 9 being, so far, unmanned.

Speaking about Orion and billions of dollars, I read an article about plans

to use the Orion on the Ariane 5 to get a European manned spaceflight

capability:

 

French govt study backs Orion Ariane 5 launch.

By Rob Coppinger

on January 8, 2010 4:45 PM

http://www.flightglobal.com/blogs/hyperbola/2010/01/french.html

 

This would cost several billion dollars to man-rate the Ariane 5. I have to

believe the solid rocket boosters, which can not be shut down when started,

play a significant role in that high cost. The article mentions also the

core stage would have to be strengthened. But such strengthening is based on

it having to support a 20 mT Orion capsule and a 20 mT upper stage which

wouldn't be used with a much smaller capsule such as the Dragon, at a dry mass

of about 4 mT.

Note also that quite likely an even smaller manned capsule could be designed

at about a 2 mT dry mass to carry a 3 man crew, which given its half size

compared to the Dragon, might cost in the range of only $150 million to

develop as privately financed. It's hard to imagine that private investment

could not be found to finance such a capsule development when it could lead to

a manned European space capability.

In regards to the costs of a privately financed SSTO version of the Ariane

launcher we might make a comparison to the Falcon 9. It cost about $300

million to develop and this includes both the structure and engines, the

engines making up the largest share of the development cost of a launcher. But

for the SSTO Ariane both engine and structure are already developed and it's

only a single stage instead of the two stages of the Falcon 9. You would have

the development cost of adding 2 additional engines and of the new avionics,

but again I have to be believe the development cost would once again be less

than the SpaceX development cost of the Falcon 9 if privately financed.

 

I also read that the ESA is attempting to decide whether to upgrade the

Ariane 5 or move to a Next Generation Launcher(NGL):

 

Ariane rocket aims to pick up the pace.

25 June 2011 Last updated at 06:39 ET

http://www.bbc.co.uk/news/science-environment-13911901

 

Thu, 9 February, 2012

France, Germany To Establish Working Group To Resolve Ariane 5 Differences.

By Peter B. de Selding

http://www.spacenews.com/policy/120209-france-germany-resolve-ariane5-differences.html

 

If the NGL is chosen then a quite expensive new large engine development

would have to be made, and the launcher might not enter service until 2025. In

contrast the SSTO-Ariane, given that the engine and stage already exist, a

prototype probably could be ready within 1 to 2 years, and moreover by using a

second stage it could also be used to launch the medium sized payloads.

 

So the SSTO-Ariane would solve the twin problems at low cost of providing

Europe with a manned spaceflight capability and giving it a lower cost medium

lift capability.

 

 

Bob Clark

 

 

 

======================================================================

Newsgroups: sci.space.policy, sci.astro, sci.physics, sci.space.history, rec.arts.sf.science

From: Robert Clark

Date: Thu, 8 Sep 2011 13:56:20 -0700 (PDT)

Subject: Re: A kerosene-fueled X-33 as a single stage to orbit vehicle.

 

I saw this discussed on a space oriented forum:

 

WSJ: Europe Ends Independent Pursuit of Manned Space Travel.

"LE BOURGET, France—Europe appears to have abandoned all hope of

independently pursuing human space exploration, even as the region's

politicians and aerospace industry leaders complain about shrinking

U.S. commitment to various space ventures.

"After years of sitting on the fence regarding a separate, pan-

European manned space program, comments by senior government and

industry officials at the Paris Air Show here underscore that budget

pressures and other shifting priorities have effectively killed that

longtime dream."

http://www.orbiter-forum.com/showthread.php?t=23006

 

In this post I discussed getting a SSTO by replacing the Vulcain

engine on the Ariane 5 core with a SSME:

 

Newsgroups: sci.space.policy, sci.astro, sci.physics, sci.space.history

From: Robert Clark

Date: Wed, 23 Feb 2011 10:14:42 -0800 (PST)

Subject: Re: Some proposals for low cost heavy lift launchers.

http://groups.google.com/group/sci.physics/msg/e1736e7586cc269f?hl=en

 

However, in point of fact Europe can produce a manned launch vehicle

from currently *existing*, European components. This will consist of

the Ariane 5 and three Vulcain engines. The calculations below use the

Ariane 5 generic "G" version. You might need to add another Vulcain

for the larger evolution "E" version of the Ariane 5 core.

In a following post I'll also show that the Hermes spaceplane also

can become a SSTO by filling the entire fuselage aft of the cockpit

with hydrocarbon propellant.

The impetus for trying the calculation for a Ariane 5 core based SSTO

using Vulcains instead of the SSME was from a report by SpaceX that

you could get the same performance from a planned heavy lift first

stage using a lower performance Merlin 2 compared to the high

performance RS-84 engine. The reason was the lower Isp of the Merlin

was made up for by its lower weight.

 

THIS IS A VERY IMPORTANT FACT BECAUSE WHAT IT MEANS IS THAT YOU DON'T

NEED THE HIGH PERFORMANCE ENGINES TO GET THE SSTO. YOU CAN USE ENGINES

OF LOWER CHAMBER PRESSURE AND SIMPLER COMBUSTION CYCLES, SUCH AS THE

VULCAIN WITH A CA. 100 BAR COMBUSTION PRESSURE AND A GAS GENERATOR

CYCLE. THIS MEANS THE ENGINES ARE CHEAPER, EASIER TO MAKE REUSABLE,

REQUIRE LESS ROUTINE MAINTENANCE, AND CAN LAST FOR MANY RESTARTS.

 

In the discussion of the Ariane/Vulcain SSTO below, I note you can

get a prototype, test vehicle quite quickly since the components are

already existing. To improve the payload though you would want to use

altitude compensation on the Vulcains. In a following post I'll

discuss some methods of altitude compensation.

In regards to achieving this at low cost, I think the most important

accomplishment of SpaceX might turn out to be that they showed in

stark terms that privately financed spacecraft, both launchers and

crew capsules, can be accomplished at 1/10th the developmental cost of

government financed ones. Imagine a manned, reusable orbital launcher,

for example, instead of costing, say, $3 billion, only costing $300

million to develop.

Here's how you can get an all European manned SSTO using the Ariane 5

core stage but with Vulcain engines this time. Note that this is one

that can be produced from currently existing components, aside from

the capsule, so at least an unmanned prototype vehicle can be

manufactured and tested in the short term and at lowered development

cost.

We'll use three Vulcain 2's instead of the 1 normally used with the

Ariane 5 core stage. There are varying specifications given on the

Vulcain 2 depending on the source. I'll use the Astronautix site:

 

Vulcain 2.

http://www.astronautix.com/engines/vulcain2.htm

 

From the sea level thrust given there, using three Vulcain 2's will

give us one engine out capability. The weight is given as 1,800 kg. So

adding on two will take the dry mass from 12 mT to 15.6 mT.

To calculate the delta-V achieved I'll use the idea again to just use

the vacuum Isp, but adding the loss due to back pressure onto the

delta-V required for orbit, as I discussed previously. However, here

for hydrogen fuel which has higher gravity loss, I'll use a higher

required delta-V of 9,400 m/s when you add on the back pressure loss.

With the vacuum Isp given for the Vulcain 2 of 434 s, we get a payload

of 3.8 mT:

 

434*9.8ln(1+158/(15.6+3.8)) = 9,412 m/s.

 

Note this is just using the standard nozzle Isp for the Vulcain, no

altitude compensation. So this could be tested, like, tomorrow.

However, for a SSTO you definitely want to use altitude compensation.

Using engine performance programs such as ProPEP we can calculate that

using long nozzles, you can get a vacuum Isp of 470 s for this engine.

As a point of comparison of how high an Isp you can get even with a

low chamber pressure engine as long as you have a long nozzle, or

equivalent, note that the RL10-B2 with a ca. 250 to 1 area ratio, and

only a ca. 40 bar chamber pressure, gets a 465 s vacuum Isp. So we'll

assume we can get a comparable Isp by using altitude compensation.

This allows us to get payload of 8 mT:

 

470*9.8ln(1+158/(15.6+8) = 9,400 m/s.

 

This allows us to add a Dragon-sized capsule and also the reentry and

landing systems to make it reusable.

 

 

Bob Clark

======================================================================

Edited March 31, 2012 by Robert Clark

[RGClark]

I've been arguing that SSTO's are actually easy because how to achieve

them is perfectly obvious: use the most weight optimized stages and

most Isp efficient engines at the same time, i.e., optimize both

components of the rocket equation. But I've recently found it's even

easier than that! It turns out you don't even need the engines to be

of particularly high efficiency.

SpaceX is moving rapidly towards testing its Grasshopper scaled-down

version of a reusable Falcon 9 first stage:

 

Reusable rocket prototype almost ready for first liftoff.

BY STEPHEN CLARK

SPACEFLIGHT NOW

Posted: July 9, 2012

http://www.spaceflightnow.com/news/n1207/10grasshopper/

 

SpaceX deserves kudos for achieving a highly weight optimized Falcon 9

first stage at a 20 to 1 mass ratio. However, the Merlin 1C engine has

an Isp no better than the engines we had in the early sixties at 304

s, and the Merlin 1D is only slightly better on the Isp scale at 311 s.

This is well below the highest efficiency kerosene engines (Russian)

we have now whose Isp's are in the 330's. So I thought that closed

the door on the Falcon 9 first stage being SSTO.

 

However, I was surprised when I did the calculation that because of

the Merlin 1D's lower weight, the Falcon 9 first stage could indeed be

SSTO. For the calculation we'll need the F9 dry mass and propellant

mass. I'll use the Falcon 9 specifications estimated by GW Johnson, a

former rocket engineer, now math professor:

 

WEDNESDAY, DECEMBER 14, 2011

Reusability in Launch Rockets.

http://exrocketman.blogspot.com/2011...h-rockets.html

 

The first stage propellant load is given as 553,000 lbs, 250,000 kg,

and the dry weight as 30,000 lbs, 13,600 kg.

 

I'll actually calculate the payload for the first stage of the new version of

the Falcon 9, version 1.1. The Falcon Heavy will use this version's first stage

for its core stage and side boosters. SpaceX expects the Falcon 9 v1.1

to be ready by the end of the year.

 

Elon Musk has said version 1.1 will be about 50% longer:

 

Q&A with SpaceX founder and chief designer Elon Musk.

BY STEPHEN CLARK

SPACEFLIGHT NOW

Posted: May 18, 2012

http://www.spaceflightnow.com/falcon9/003/120518musk/

 

I'll assume this is coming from 50% larger tanks. This puts the

propellant load now at 375,000 kg. Interestingly SpaceX says the side

boosters on the Falcon Heavy will have a 30 to 1 mass ratio. This

improvement is probably coming from the fact it is using the lighter

Merlin 1D engines, and because scaling up a rocket actually improves

your mass ratio, and also not having to support the weight of an upper

stage and heavy payload means it can be made lighter.

 

So I'll assume for this SSTO version of the Falcon 9 v1.1 the mass

ratio is 30 to 1, which makes the dry mass 13 mT.

 

To estimate the payload I'll use the payload estimation program of

Dr. John Schilling:

 

Launch Vehicle Performance Calculator.

http://www.silverbirdastronautics.com/LVperform.html

 

It actually gives a range of likely values of the payload. But I've found

the midpoint of the range it specifies is a reasonably accurate estimate

to the actual payload for known rockets.

 

Input the vacuum values for the thrust in kilonewtons and Isp in

seconds. The program takes into account the sea level loss. SpaceX

gives the Merlin 1D vacuum thrust as 161,000 lbs and vacuum Isp

as 311 s:

 

FALCON 9 OVERVIEW.

http://www.spacex.com/falcon9.php

 

For the 9 Merlins this is a thrust of 9*161,000lb*4.46N/lb = 6,460

kN. Use the default altitude of 185 km and select the Cape Canaveral

launch site, with a 28.5 degree orbital inclination to match the

Cape's latitude.

 

Input the dry mass of 13,000 kg and propellant mass of 375,000 kg.

The other options I selected are indicated here:

 

 

Then it gives an estimated 7,564 kg payload mass:

 

=====================================

Launch Vehicle: User-Defined Launch Vehicle

Launch Site: Cape Canaveral / KSC

Destination Orbit: 185 x 185 km, 28 deg

Estimated Payload: 7564 kg

95% Confidence Interval: 3766 - 12191 kg

=====================================

 

This may be enough to launch the Dragon capsule, depending on the mas

of the Launch Abort System(LAS).

 

 

Bob Clark

[CraigD]

Launch Vehicle Performance Calculator.

http://www.silverbirdastronautics.com/LVperform.html

:thumbs_up That’s a neat little calculator, though I wish its “methodology used” page showed its actual code. I enjoy writing simple simulators myself, and posted the code for a few in the space forum years ago, before my and others interest and enthusiasm in writing a really useful, more complicated one fizzled out. Though I expect there are lots of tried and true simulators practically or fully in the public domain, there’s no substitute, IMHO, for writing your own. :)

 

I’m a bit wary of accepting its calculations showing SSTO-capability using SpaceX Falcon rockets, as if this were truly the case, I’d expect SpaceX, not a company shy of making grand promises, and one I’m sure has excellent high detail simulators, would have made it known years or more ago.

 

Until actually running a detailed simulation, I have to remain skeptical – not of the possibility of SSTO, but of how easy calculators like this suggest it is.

 

SpaceX is moving rapidly towards testing its Grasshopper scaled-down

version of a reusable Falcon 9 first stage:

 

Reusable rocket prototype almost ready for first liftoff.

BY STEPHEN CLARK

SPACEFLIGHT NOW

Posted: July 9, 2012

http://www.spaceflightnow.com/news/n1207/10grasshopper/

I’ve been enthused since first reading of SpaceX’s ambitions to make the currently disposable Dragon reusable via the oh so cool sounding means of landing them with their own main engines, and am delighted to see serious work being done toward that.

 

I’m wary, though, of statements like these, from the article:

"If one can figure out how to effectively reuse the rockets just like an airplane, the cost of access to space will be reduced by as much as a factor of a hundred," [spaceX CEO and founder Elon] Musk said. "A fully reusable vehicle has never been done before. That really is the fundamental breakthrough that is needed to revolutionize access to space."

This “dramatically reduce cost through reusability” argument seems pretty much the same as the one made in the 1970s in promotion of the STS (Space Shuttle, or as it was often promoted as “space truck” system), which, with the exception of a single component, its engineless external fuel tank, was a fully reusable system, yet proved to be more expensive than many disposable systems, because of the great cost of reconditioning its reusable hardware after each use.

 

The analogy of an airplane to a rocket can be a deceptive one, in greatest part because airplane engines and other components are designed for durability, at the expense of greatest power/mass ratios. A typical jet aircraft engine need be overhauled every 3000 to 5000 hours, vs. (using the Shuttle as an example) every 8 to 10 minutes for rocket engines.

 

Though the reduced cost through reusability argument is intuitively appealing, precisely because of our experience with airplanes, cars, and other vehicles with very durable engines and other parts. High I_sp rocket motors are machines of a quite different sort.

 

Like any decent space fan, a SSTO vehicle as cheap and reliable as the car in my driveway (or plane in my hanger, if I was one of the many folk fortunate enough to have one) is among my fondest dreams. But I’ve learned to beware of intuitively appealing mantras like “just make it reusable, like an airplane,” even when the person saying them is someone like the uber-cool Elon Musk.

 

I think that if reusable SSTO (or multi-reusable stage to orbit) is ever to really reduce the dramatically cost of spaceflight, more attention needs to be given to making rocket motors so durable that they can be reused without significant reconditioning work. As I see things now, informed by the experience of the disappointingly costly STS program, it’s little, if at all, cheaper to reuse a rocket than to build a new one from scratch.

[RGClark]

:thumbs_up That’s a neat little calculator, though I wish its “methodology used” page showed its actual code. I enjoy writing simple simulators myself, and posted the code for a few in the space forum years ago, before my and others interest and enthusiasm in writing a really useful, more complicated one fizzled out. Though I expect there are lots of tried and true simulators practically or fully in the public domain, there’s no substitute, IMHO, for writing your own. :)

I’m a bit wary of accepting its calculations showing SSTO-capability using SpaceX Falcon rockets, as if this were truly the case, I’d expect SpaceX, not a company shy of making grand promises, and one I’m sure has excellent high detail simulators, would have made it known years or more ago.

Until actually running a detailed simulation, I have to remain skeptical – not of the possibility of SSTO, but of how easy calculators like this suggest it is.

...

 

Thanks for the informative response. It's all theoretical until Spacex fields the Falcon 9 v1.1 later this year and the Falcon Heavy including those side boosters next year.

If the Falcon 9 v1.1 first stage mass ratio is anywhere close to 30 to 1, as SpaceX claims the FH side boosters will be, then that will raise the questions about whether it can be SSTO.

If it can be, then that raises the possibility that by using higher efficiency engines such as the NK-33 or RD-180 we can get an economic SSTO even with reusability.

 

Bob Clark