Orbital Sciences rocket explodes over pad

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"William Mook" wrote in message
...

Thrust scales with exhaust area.
Explosive energy scales with combustion chamber volume.
Weight also scales with volume.

Therefore, reducing engine size, and increasing their number, increases
thrust to weight, and increases thrust to explosive energy.

https://blogs.nasa.gov/J2X/tag/rl10-rocket-engine/

This combustion chamber contains the explosive power of about 150 grams of
dynamite and produces 40x its weight as thrust force.

https://www.youtube.com/watch?v=ssiaieFGYtY

Using MEMS techniques to reduce the size of this engine by a factor of 30 we
increase thrust to 1200x its weight and reduce the explosive potential of a
given rocket chamber to 500 milligrams of dynamite!
....
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That would be great if it were achieved. However, there has not yet been
produced a MEMS engine that reaches anywhere close to the 40-to-1 and higher
thrust to weight ratios of current large-sized engines.

Bob Clark

On Thursday, December 4, 2014 1:51:05 PM UTC+13, Robert Clark wrote:
================================================== =====
"William Mook" wrote in message
...

Thrust scales with exhaust area.
Explosive energy scales with combustion chamber volume.
Weight also scales with volume.

Therefore, reducing engine size, and increasing their number, increases
thrust to weight, and increases thrust to explosive energy.

https://blogs.nasa.gov/J2X/tag/rl10-rocket-engine/

This combustion chamber contains the explosive power of about 150 grams of
dynamite and produces 40x its weight as thrust force.

https://www.youtube.com/watch?v=ssiaieFGYtY

Using MEMS techniques to reduce the size of this engine by a factor of 30 we
increase thrust to 1200x its weight and reduce the explosive potential of a
given rocket chamber to 500 milligrams of dynamite!
...
================================================== =====

That would be great if it were achieved. However, there has not yet been
produced a MEMS engine that reaches anywhere close to the 40-to-1 and higher
thrust to weight ratios of current large-sized engines.

Bob Clark

Bob, Epstein reported in an AIAA that MIT achieved 1000 to 1 thrust to weight ten years ago.

http://cap.ee.ic.ac.uk/~pdm97/powerm...53_Epstein.pdf

The abstract says, "This paper is an overview of the research at MIT on MEMS liquid bipropellant rocket engines. Sized to provide 10-15N of thrust at a thrust-to-weight ratio of about 1000:1, these engines have specific impulse approaching the theoretical value achievable for the propellants. The motivation for this effort is twofold: first, to explore the high power density boundaries of micro-rocket propulsion systems, and second, to demonstrate a useful propulsion capability. The basic approach is to engineer miniature versions of rocket engine subsystems - thrust chamber, exhaust nozzle, turbopumps, valves - redesigned to be compatible with conventional MEMS silicon processing technology. Work has also been done to characterize the thermo-fluid behavior of rocket propellants at conditions representative of the MEMS rocket engine operating environment."

Substantial progress has been made since then.

3D additive manufacturing technology using refractory metals, that has 1 micron resolution, with a 1 cubic meter build volume, can do quite a bit as well.

http://3dprintingsystems.com/additiv...-using-metals/

On Wednesday, December 3, 2014 8:14:09 PM UTC-5, William Mook wrote:
On Thursday, December 4, 2014 1:51:05 PM UTC+13, Robert Clark wrote:
That would be great if it were achieved. However, there has not yet been
produced a MEMS engine that reaches anywhere close to the 40-to-1 and higher
thrust to weight ratios of current large-sized engines.

Bob Clark

Bob, Epstein reported in an AIAA that MIT achieved 1000 to 1 thrust to weight ten years ago.

http://cap.ee.ic.ac.uk/~pdm97/powerm...53_Epstein.pdf

The abstract says, "This paper is an overview of the research at MIT on MEMS liquid bipropellant rocket engines. Sized to provide 10-15N of thrust at a thrust-to-weight ratio of about 1000:1, these engines have specific impulse approaching the theoretical value achievable for the propellants. The motivation for this effort is twofold: first, to explore the high power density boundaries of micro-rocket propulsion systems, and second, to demonstrate a useful propulsion capability. The basic approach is to engineer miniature versions of rocket engine subsystems - thrust chamber, exhaust nozzle, turbopumps, valves - redesigned to be compatible with conventional MEMS silicon processing technology. Work has also been done to characterize the thermo-fluid behavior of rocket propellants at conditions representative of the MEMS rocket engine operating environment."

Substantial progress has been made since then.


Cite? If you read beyond the abstract of the cited paper above you see this quote:

"The work to date at MIT has focused on demonstrating op-
eration of the individual components of a MEMS bipropel-
lant chemical rocket engine system. Once this is completed,
the next step is to demonstrate the complete system, with
components integrated with external packaging. Flight sys-
tems will require wafer or die level component integration as
well as multi-engine interconnection schemes to enable
groups of engines to work together and be robust to individ-
ual failure"

Operation of components is not the same as an operational engine.
That an investigatory paper was written ten years ago is not the same as saying that a 1000:1 T/W engine was developed 10 years ago.

Do you have anything more recent from Epstein?


3D additive manufacturing technology using refractory metals, that has 1 micron resolution, with a 1 cubic meter build volume, can do quite a bit as well.

http://3dprintingsystems.com/additiv...-using-metals/

Yes but they say they can do:
"Components can be produced to an accuracy of 80 µ and with unfinished surface quality of 150 µ"

Whereas the paper previously cited mentions flow sensors alone that were already at 50u. Looks like an apples to oranges comparison to me.

Dave

In article ,
says...

That would be great if it were achieved. However, there has not yet been
produced a MEMS engine that reaches anywhere close to the 40-to-1 and higher
thrust to weight ratios of current large-sized engines.

Details, schmetails. Mook thinks he can pick and choose the numbers he
uses in his "math" to "prove" that something in the lab will work in the
real work in an application it was never designed for.

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...
3D additive manufacturing technology using refractory metals, that has 1 micron resolution, with a 1 cubic meter build volume, can do quite a bit as well.

http://3dprintingsystems.com/additiv...-using-metals/

Yes but they say they can do:
"Components can be produced to an accuracy of 80 µ and with unfinished surface quality of 150 µ"

Whereas the paper previously cited mentions flow sensors alone that were already at 50u. Looks like an apples to oranges comparison to me.


You just don't understand Mook-math. The only way I've found to make it
work is to put it in a killfile or pipe the output directly to
/dev/null.

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 Friday, December 5, 2014 9:07:19 AM UTC+13, David Spain wrote:
On Wednesday, December 3, 2014 8:14:09 PM UTC-5, William Mook wrote:
On Thursday, December 4, 2014 1:51:05 PM UTC+13, Robert Clark wrote:
That would be great if it were achieved. However, there has not yet been
produced a MEMS engine that reaches anywhere close to the 40-to-1 and higher
thrust to weight ratios of current large-sized engines.

Bob Clark

Bob, Epstein reported in an AIAA that MIT achieved 1000 to 1 thrust to weight ten years ago.

http://cap.ee.ic.ac.uk/~pdm97/powerm...53_Epstein.pdf

The abstract says, "This paper is an overview of the research at MIT on MEMS liquid bipropellant rocket engines. Sized to provide 10-15N of thrust at a thrust-to-weight ratio of about 1000:1, these engines have specific impulse approaching the theoretical value achievable for the propellants. The motivation for this effort is twofold: first, to explore the high power density boundaries of micro-rocket propulsion systems, and second, to demonstrate a useful propulsion capability. The basic approach is to engineer miniature versions of rocket engine subsystems - thrust chamber, exhaust nozzle, turbopumps, valves - redesigned to be compatible with conventional MEMS silicon processing technology. Work has also been done to characterize the thermo-fluid behavior of rocket propellants at conditions representative of the MEMS rocket engine operating environment."

Substantial progress has been made since then.


Cite? If you read beyond the abstract of the cited paper above you see this quote:

"The work to date at MIT has focused on demonstrating op-
eration of the individual components of a MEMS bipropel-
lant chemical rocket engine system. Once this is completed,
the next step is to demonstrate the complete system, with
components integrated with external packaging. Flight sys-
tems will require wafer or die level component integration as
well as multi-engine interconnection schemes to enable
groups of engines to work together and be robust to individ-
ual failure"

Operation of components is not the same as an operational engine.
That an investigatory paper was written ten years ago is not the same as saying that a 1000:1 T/W engine was developed 10 years ago.

Do you have anything more recent from Epstein?

If you can get behind various pay walls - there are many more recent articles. All you have to do is ask. If you have access you can search as easily as I.

If you don't have access, pointers to pay walls won't help you.

Anyone can look at a recent AIAA call for papers and you can get an idea of the importance of this micropropulsion topic;

https://www.aiaa.org/Scitech2013CFP/

Micro-Combustion and Micro-Propulsion: micro-scale combustion for power generation, micro-IC engines, micro-propulsion engines, and micro-thrusters

The values I report are in the literature.

Bob's comment, "That would be great if it were achieved. However, there has not yet been produced" is wrong.

His comment that "a MEMS engine that reaches anywhere close to the 40-to-1 and higher thrust to weight ratios of current large-sized engines." Was dead wrong fifteen years ago, and certainly dead wrong today!

Fact is bipropellant rocket engines with 1000 to 1 thrust to weight are available and they are made into vast arrays of highly controllable engines - creating propulsive surfaces with 50 psi pressure capability.

With $10 per square inch manufacturing costs, this is $0.20 per pound force of thrust! With appropriate investment in technology, that price drops another factor of eight!

3D additive manufacturing technology using refractory metals, that has 1 micron resolution, with a 1 cubic meter build volume, can do quite a bit as well.

http://3dprintingsystems.com/additiv...-using-metals/

Yes but they say they can do:
"Components can be produced to an accuracy of 80 µ and with unfinished surface quality of 150 µ"

Whereas the paper previously cited mentions flow sensors alone that were already at 50u. Looks like an apples to oranges comparison to me.

Dave

Of course there are more recent papers.

Bob Clark's point that 40 to 1 is difficult to achieve is absolutely wrong. Epstein's paper from 15 years ago proves that.

Now you bring up that a University lab was limited to 150 micron resolution 15 years ago and try to make us believe that's some sort of ultimate limit! lol. That's dead wrong too!

There are manufacturers out there today willing to state publicly they produce fully dense metal parts to 2 µ resolution - as stated here;

http://www.microfabrica.com/

They can do one micron if you ask them!

There are others that build very large build volumes as well.

Even with a limited production run at builders like Microfabrica, a 300 mm wafer costing $1,095 has 109.5 square inches of usable surface- built into an array each wafer produces 5,500 pounds force of thrust! A $25,000 set up charge, and 24 wafers cost a grand total of $50,000 - producing arrays that total 110,000 lbf thrust!

Now, if you have more money than most folks can get from their local bank, that is if you're really in this sort of business, you can approach folks who have the sorts of facilities to be a real game changer in this field.

This is the paradigm shift you will see in the next three to five years!

You may recall I said 20 years ago that computing technology will make autonomous drones commonplace. We have that.

At that time I also said plasma TV manufacturers had all the skill sets necessary to dominate the emerging market of propulsive surface arrays. I also said that by the time the technology matures, those assets will be picked up cheaply since plasma will be at the end of its useful life about this time frame.

I was right about that too, of course!

This is what I'm focusing on at the present moment.

Check it out!

http://www.reuters.com/article/2013/...9980IO20131009

http://www.marke****ch.com/story/pan...ite-2014-02-18

http://www.flatpanelshd.com/news.php...&id=1320237339

Now the pricing of Plasma is interesting... the RETAIL price vs. size is given here;

http://www.rtings.com/images/plasma-vs-led-tv-price.png

Consider a 65" Plasma TV

A 65" HDTV is a 56.65 inch by 31.87 inch area that has 1920 ports by 1080 ports for each colour supported by the screen. This is a pixel size less than 750 microns across.

Since there are four colours in the Panasonic models of this size range, this is 2,073,600 ports times four! Over 8.2 million plasma ports. Each one highly controllable. A 375 micron diameter port for each colour.

http://download.e-bookshelf.de/downl...m_img_3_17.jpg

The cost is $2.77 per square inch RETAIL. Less than $1.50 per square inch at the manufacturing level.

What does this mean?

Well, using this tool set to make rocket engine arrays instead of arrays of glowing plasma - produce thrusts at 50 psi. This drops the cost of thrust down to less than $0.03 per pound!

A 65" screen size, converted to a micro-rocket array produces 54,250 pounds of thrust for $4,000 retail - $2,500 wholesale!!

Of course engineering and acquisition costs rise to about $400 million. But you have a tool set to produce 40,000 of these a day - a total of 2.16 billion pounds of thrust per day.

At 10,000 lbs thrust per vehicle - we have the ability to build propulsion systems for 216,000 vehicles per day! This from a single plasma screen plant!

Panasonic in 2009 displayed a 103" 4K UHDTV so large sizes are possible! They also showed a curved ultra-thin display in 2011 so curved surfaces are possible!

Obviously, with the right kind of money, and the right talent, we can build a variety of propulsive skin capabilities adapting this technology in a very short time period!

Built into aircraft and spacecraft surfaces, we can envision on demand air transport between any point on Earth when merged with drone technology.

Consider six passenger seats in a conical vehicle oriented radially outward, behind an access door, all around a central propellant tank, propelled by an aerospike engine MEMS at the base, using hydrogen, LOX and atmospheric oxygen. This vehicle is capable of transporting up to six passengers and up to 600 kg up to 4,000 km in a matter of minutes and refuelling in another few seconds, while reloading with another set of passengers!

http://psipunk.com/wp-content/upload...ce-ship-01.jpg

With 1800 kg inert and payload weight and 2,200 kg of propellant, of which 400 kg is hydrogen, we have need of 75 MW of power to convert the requisite water into hydrogen and oxygen to maintain each vehicle fuelled for continuous operation.

Smaller drone vehicles - transport packages on demand.

This isn't the only form possible of course. Only indicative.

Propulsive skins can be woven into fabrics, along with sensing systems that calculate the orientation and position of each propulsive element. This allows one to develop wearable propulsive skins that give people the freedom of flight.

https://www.youtube.com/watch?v=iVDD5cF1IX4

Of course with more energetic propulsion, involving controlled aneutronic fusion, more interesting things are possible;

https://www.youtube.com/watch?v=ZwOxM0-byvc
https://www.youtube.com/watch?v=7phiJ-vxr0A

In the Iron Man movie, the fictional Jarvis echoes fictional HAL 9000 in its capabilities.

https://www.youtube.com/watch?v=Zf2lBfb1vXI

Now, when the Iron Man movie was made, and certainly when Iron Man was first written about in the comic books, the computer "Jarvis" as totally fictional as was HAL 9000. Of course, the problem of human level computing is solved these days;

https://www.youtube.com/watch?v=lI-M7O_bRNg

Hopefully it won't go too badly for us humans!

https://www.youtube.com/watch?v=5Oq--MeUjgI
https://www.youtube.com/watch?v=J1xJYK4Rj7I
https://www.youtube.com/watch?v=7Pq-S557XQU
https://www.youtube.com/watch?v=_P9HqHVPeik