SSTO one step closer

Reaction Engines completes precooler testing

http://www.reactionengines.co.uk/news_updates.html

In article ,
ess says...

Reaction Engines completes precooler testing

http://www.reactionengines.co.uk/news_updates.html

Congrats on the precooler testing, now they need to move on to the next
phase of R&D. See: .signature

Put this head to head with SpaceX's Grasshopper and tell me which one is
going to be cheaper to develop and will be flying on an operational
launcher sooner.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Jeff Findley wrote:
ess says...

Reaction Engines completes precooler testing
http://www.reactionengines.co.uk/news_updates.html

Congrats on the precooler testing, now they need to move on to the next
phase of R&D. See: .signature

As good quoting deletes the .signature I've inserted it back -

"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

When I first went to college there was the dream that a space shuttle
would have a large first stage air breathing launch vehicle. It would
have turbine and/or ramjet engines. My initial major was mechanical
engineering targeting turbine machines because I wanted to work on that
project, so I'm both biased and obsolete on this topic but I knew the
issues in the late 1970s early 1980s. (Then I discovered that every
assignment that had computer work was an assignment I liked more than
others. So I switched to computers and have been doing them ever
since).

A launch stage doesn't need to be hypersonic to be worth it. Much of
the energy of a ground launch rocket is spent getting the vehicle up
into thin air. A subsonic jet can do that. Some of the energy of a
ground rocket is spent getting the rocket to subsonic horizontal speeds
before going supersonic. A subsonic jet can do that.

Given this, to me the price difference of a supersonic air breathing
launch stage versus a subsonic air breathing launch stage is larger
than the payload difference justifies. We can go as far back as
dropping the X-15 from the wing of a B-52 to demonstrate this. Now at
least Spaceship-One uses a subsonic launch stage. Get it up as high as
feasable into thin air. Put the plane on an arc that gives some more
up plus as much forward as it can. Do the math to see what arc works
best as the trade off between verticle loft and horizontal speed. Do
that arc and release at the point described in the math. The launch
vehicle might or might not stall, might or might not flame out but
it's plenty high enough to recover.

Add rocket packs that burn out and drop down on chutes ater a suborbital
arc? If the math and engineering compromises say that's the way to go
given any one specific design.

Given current engineering I figure subsonic air breathing launch stage
is one of the better ways to go. How long before it's beat by direct
rocket launch? We have already seen direct rocket launch in action for
decades. It's led to very large disposable first stages.

In article ers.net,
says...

The development has so far been low-cost (about $20 million), but to
make a real Skylon spaceplane the company has said it would need $12
billion!!! Let me put it this way: it will never happen.

People seem to forget the political dimension. The French will never
allow EU money to be used for a British spaceplane, they want to keep
all space-based development in France. Germany is
currently fighting France tooth and nail over the work on the new
Ariane-6, the Germans want at least 50% of the new rocket to be German.
Other EU countries are only allowed to pick up the crumbs
off the floor. How long before these nations start to clamor about this
and demand a much greater role in the rocket's design and production?

The only hope Britain has of seeing the Skylon become a reality is to
team up with the Americans. There's little chance of that succeeding
since U.S. politicians don't like their nation's space
transportation systems being based on foreign tech.

The US is already spending its billions on SLS, which keeps spending
flowing to all the right congressional districts, which is exactly what
US politics dictates. Because of this, from a political point of view,
SLS will be successful even if it never flies. My bet is that it will
fly, but will be too expensive to fly (on average) much more than once
or twice a year.

From a technical point of view, it's too bad that SLS is nothing more
than a warmed over shuttle derived launch vehicle which does little to
nothing to advance the state of the art in reusable launch vehicle
hardware.

:-(

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

In article , says...

When I first went to college there was the dream that a space shuttle
would have a large first stage air breathing launch vehicle. It would
have turbine and/or ramjet engines. My initial major was mechanical
engineering targeting turbine machines because I wanted to work on that
project, so I'm both biased and obsolete on this topic but I knew the
issues in the late 1970s early 1980s. (Then I discovered that every
assignment that had computer work was an assignment I liked more than
others. So I switched to computers and have been doing them ever
since).

A launch stage doesn't need to be hypersonic to be worth it. Much of
the energy of a ground launch rocket is spent getting the vehicle up
into thin air. A subsonic jet can do that. Some of the energy of a
ground rocket is spent getting the rocket to subsonic horizontal speeds
before going supersonic. A subsonic jet can do that.

Given this, to me the price difference of a supersonic air breathing
launch stage versus a subsonic air breathing launch stage is larger
than the payload difference justifies. We can go as far back as
dropping the X-15 from the wing of a B-52 to demonstrate this. Now at
least Spaceship-One uses a subsonic launch stage. Get it up as high as
feasable into thin air. Put the plane on an arc that gives some more
up plus as much forward as it can. Do the math to see what arc works
best as the trade off between verticle loft and horizontal speed. Do
that arc and release at the point described in the math. The launch
vehicle might or might not stall, might or might not flame out but
it's plenty high enough to recover.

Add rocket packs that burn out and drop down on chutes ater a suborbital
arc? If the math and engineering compromises say that's the way to go
given any one specific design.

Given current engineering I figure subsonic air breathing launch stage
is one of the better ways to go. How long before it's beat by direct
rocket launch? We have already seen direct rocket launch in action for
decades. It's led to very large disposable first stages.

So far, subsonic air launch hasn't been terribly successful due to the
need for a *very* large carrier aircraft for what I'd consider to be a
"reasonable" sized payload to orbit. Stratolaunch plans to build its
subsonic carrier out of two Boeing 747's.

http://en.wikipedia.org/wiki/Stratolaunch_Systems

SpaceX recently announced that it has parted ways with the Stratolaunch
Systems's air launch scheme. Stratolaunch has switched to Orbital
Sciences as the provider of the rocket stages.

It's nice to see SpaceX and Stratolaunch are taking two different
approaches to "first stage" reusability. This is exactly the sort of
competition the industry needs, IMHO. Time will tell if either (or
both) of these approaches proves successful.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

In article ,
says...
So far, subsonic air launch hasn't been terribly successful due to the
need for a *very* large carrier aircraft for what I'd consider to be a
"reasonable" sized payload to orbit. Stratolaunch plans to build its
subsonic carrier out of two Boeing 747's.

http://en.wikipedia.org/wiki/Stratolaunch_Systems

I wasn't very clear about their aircraft plans. They're pulling major
*parts* from the 747's, but the aircraft itself (fuselages, wings, etc.)
will be new composite based structures.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

On Nov 30, 10:52*am, Doug Freyburger wrote:
Jeff Findley wrote:
says...

Reaction Engines completes precooler testing
http://www.reactionengines.co.uk/news_updates.html

Congrats on the precooler testing, now they need to move on to the next
phase of R&D. *See: .signature

As good quoting deletes the .signature I've inserted it back -

"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

When I first went to college there was the dream that a space shuttle
would have a large first stage air breathing launch vehicle. *It would
have turbine and/or ramjet engines. *My initial major was mechanical
engineering targeting turbine machines because I wanted to work on that
project, so I'm both biased and obsolete on this topic but I knew the
issues in the late 1970s early 1980s. (Then I discovered that every
assignment that had computer work was an assignment I liked more than
others. So I switched to computers and have been doing them ever
since).

A launch stage doesn't need to be hypersonic to be worth it. *Much of
the energy of a ground launch rocket is spent getting the vehicle up
into thin air. A subsonic jet can do that. Some of the energy of a
ground rocket is spent getting the rocket to subsonic horizontal speeds
before going supersonic. *A subsonic jet can do that.

Given this, to me the price difference of a supersonic air breathing
launch stage versus a subsonic air breathing launch stage is larger
than the payload difference justifies. *We can go as far back as
dropping the X-15 from the wing of a B-52 to demonstrate this. *Now at
least Spaceship-One uses a subsonic launch stage. Get it up as high as
feasable into thin air. Put the plane on an arc that gives some more
up plus as much forward as it can. Do the math to see what arc works
best as the trade off between verticle loft and horizontal speed. Do
that arc and release at the point described in the math. The launch
vehicle might or might not stall, might or might not flame out but
it's plenty high enough to recover.

Add rocket packs that burn out and drop down on chutes ater a suborbital
arc? *If the math and engineering compromises say that's the way to go
given any one specific design.

Given current engineering I figure subsonic air breathing launch stage
is one of the better ways to go. *How long before it's beat by direct
rocket launch? *We have already seen direct rocket launch in action for
decades. *It's led to very large disposable first stages.

I have always believed this is the future of space travel, keep the
air breathing part in the air.....

SSTO just leaves too low a payload......

a advantage of a large carrier aircraft is the vehicle can launch with
little fuel and be refuled many times to release, minimizing weight.
no sweat for the air force.....

plus your almost in orbit at release. minimizes the loaded bomb launch.

On Nov 30, 6:17*pm, Fred J. McCall wrote:
bob haller wrote:

I have always believed this is the future of space travel, keep the
air breathing part in the air.....

SSTO just leaves too low a payload......

The question is whether airbreathing launch really gains you anything.
You flailing and squawking like a mad chicken isn't precisely
convincing.



a advantage of a large carrier aircraft is the vehicle can launch with
little fuel and be refuled many times to release, minimizing weight.
no sweat for the air force.....

All irrelevant. *The question is still whether there is sufficient
gain to warrant the additional expense.



plus your almost in orbit at release. minimizes the loaded bomb launch.

Sadly, I believe you really are so stupid that you believe the
preceding.

Hint: *You're nowhere near orbit at release.

--
"Ignorance is preferable to error, and he is less remote from the
*truth who believes nothing than he who believes what is wrong."
* * * * * * * * * * * * * * * *-- Thomas Jefferson

The added expense? Aircraft operations are run of the mill simple
operations today in comparison with the exotic equiptement needed for
SSTO. Plus the fuel used to release attitude, and the carrier aircraft
itself dont count in the launch weight since they really dont launch..

On Fri, 30 Nov 2012 09:54:17 -0800 (PST), bob haller
wrote:


plus your almost in orbit at release. minimizes the loaded bomb launch.

No, you're not even remotely "almost in orbit". No practical air
launch system will be supersonic at launch time (the reasons for this
are myriad) or likely much higher than 40,000 feet. That means about
600 mph and 40,000 ft. at separation.

To reach orbit you need about 17,500 mph and 400,000 ft.

600mph/40,000 feet buys you a little improvement for space launch, but
honestly I don't see the cost/benefit ration as being at all
worthwhile. Didn't Elon Musk say air-launch only saves 5% vs. a
typical Falcon 9 launch?

I think StratoLaunch will quietly disappear.

Brian

"Jeff Findley" wrote in message
...
In article ,
ess says...

Reaction Engines completes precooler testing

http://www.reactionengines.co.uk/news_updates.html

Congrats on the precooler testing, now they need to move on to the next
phase of R&D. See: .signature

Put this head to head with SpaceX's Grasshopper and tell me which one is
going to be cheaper to develop and will be flying on an operational
launcher sooner.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer



But the wrong problem is still being solved. Lowering the
cost of space travel by an order of magnitude is not the
problem that needs to be solved.

It's finding a product from space that's an order of magnitude
more valuable. Once that product is found, cheaper access
will find a way, and in a hurry.

Money talks, sci-fi pipe-dreams like mining asteroids or colonies
walk.

And we all know there is only one commodity with that kind
of huge potential for scale, profit and need. Space Energy
doesn't have to compete, it can find all kind of energy
niches, and have them all to itself.
http://www.spaceenergy.com/


And besides, NASA should be about thinking big, about
technology that can create a better future.

Maybe the single greatest technological advance in terms
of changing the world for the better has to be AC power.
Which allowed electricity to travel far and wide in
comparison to DC. Suddenly much of the world can
access electricity ...for the first time...with that advance.

What's the next great leap forward with energy???

It's...wireless....power transmission that can have
the same kind of transformational effect on the world
Allowing access to power, for the first time, to just about
all the places AC still can't serve.

Wireless would have countless new market niches
all to itself.

Just imagine how many people around the world
might be saved and helped by truly wireless power
....falling from the sky?

I dare anyone to name any other space activity
that could have even a fraction of that potential
effect on society and the future.

The energy market is the second largest market
on Earth, just barely behind food. Some $5 Trillion
dollar a year market, where new $10 billion dollar
projects are weekly events.



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