A low cost, all European, manned launcher.

[Robert Clark]

[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.aviationw..._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.flightglo.../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...onment-13911901

 

Thu, 9 February, 2012

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

By Peter B. de Selding

http://www.spacenews...ifferences.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

Blog: http://exoscientist.blogspot.com

 

 

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

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-f...ead.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...586cc269f?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.astronaut...es/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 May 15, 2012 by Robert Clark

[MigL]

I still remember the HOTOL, Sanger and forget the name of the French concept, for a reuseable launch vehicle in the closing years of the last century.

Shuttle type launch vehicles became a maintenance nightmare and used technology from 1980 ( intel i286 processors ?? ). New technology would solve a lot of the problems and make them a viable choice rather than going backwards with the Ariane ( or Russian ) launcher.

[Enthalpy]

Big nozzles weigh a lot. This is an other limit, in addition to flow stability in the atmosphere.

The RL-10 pushes 100kN in D=2.15m so (as chamber pressure improves this very slowly) a Vulcain with 470s and 1.4MN would need a ~14 times bigger area or D=8m, both impractical and too heavy.

For comparison, Saturn-V had huge D=3.8m nozzles at the first stage, and this is more or less what solid boosters have at Ariane-V and the Shuttle, where mass is a small worry.