The Guild of Icarus: Aerospace Engineering and Aeronautical Club

[J. Wilhelm]

There's bound to be a graph or table somewhere detailing the amount of oxygen necessary for hydrogen to combust...

Not a graphic, but a yahoo answers page on the subject:

https://answers.yahoo.com/question/index?qid=20100522105309AA1bWkS

Indeed. You start by considering the molar density for a given altitude. How far you get from a stoichiometric mixture will affect flammability. But it;s a bit more complicated than that. The molecules have to interact with one another (be close enough) to actually propagate the combustion reaction. Mother Nature being what it is, this question is substantially more complicated than just calculating molar fractions, and sufficiently complicated that to date we have graduate level academic research on the subject:

https://www.fire.tc.faa.gov/pdf/TC-TT-14-36.pdf

This is a Thesis paper (brings back memories  ) from some graduate student, regarding the Lower Flammability Limit (LFL), and  Upper Flamability Limit (UFL) for hydrogen as a function of altitude.  The most interesting part, actually is the student's introduction chapter on the background history for his research.

There are a lot of factors which affect flammability.  One is that you have to define exactly what "flammable means." 

First, for all purposes we assume Hydrogen will detonate (aka conflagrate), meaning there is a flame that propagates very quickly, as opposed to explode, which is when all the hydrogen molecules simultaneously react at the same time. So explosions and detonations are two different things. Here we are talking about detonations.

Second, all gases can ignite; but whether they can maintain a chain chemical reaction is another thing. There are many factors that affect this

What was found in late 20th. research (also supported by this student;s findings) is that the LFL, expressed in percent minimum hydrogen -by volume- needed to detonate was about 4% at sea level, and as the pressure decreased at altitude, at say the lower stratosphere, 30 000 ft, then that minimum actually decreased to 3.5%. Then as altitude increases further to 17km of altitude (55 000 ft) and oxygen density decreased, then the LFL would spring back up to 4%.

The UFL does something similar going from 78% hydrogen by volume at 1 atmosphere, peaking at close to 79% at 15 000 ft and the sharply going down to 77% at 40 000 ft. and 76% by 55 000 ft.

This all means that hydrogen actually has an easier time detonating between 15 000 ft  and 30 000 ft than anywhere else! But go higher and the tables turn making it more difficult to detonate.

Presumably then as you climb higher the LFL just continues increasing, until either there simply is not enough percentage hydrogen to ignite, or the percentage of hydrogen, no matter how low would be "too rich" of a mixture.  In other words both LFL and UFL actually "merge." because the molecules are too far apart , and propagation of flame is very very slow according to that definition).

My guess is that in the stratosphere with an airship travelling at very low speeds (basically stationary with respect to the rocket) you still are at a very high risk for detonation -actually a bit higher than on the ground. This situation very much pertains to the Spaceship One type of vehicle.

If the USAS Orca was launching a "Steampunk One" spaceship at 35 000 ft. then this would be a severe risk of gas bag breach and detonation   

For the X-15 type of vehicle, at much higher altitudes your risk significantly goes down. But the question is how far up I need to go. That I don't know off-hand. If the balloon went "all the way up," then there is no uncertainty, though...

According to atmospheric data, the relative mixture of atmospheric gases is more or less constant up to 100 Km of altitude, basically, and if you go higher than the heavy gases begin to separate from the lighter gases; this is about the edge of space.  Around 90Km of altitude (relevant to the latitude ceiling of the Silbervogel and X-15) the pressure is about 3X10^-5 atmosphere, 3/100000th the pressure of air on the ground, and the density is 3X10^-6 or 3 millionths of the density in the atmosphere.  At this altitude, you definitely can't sustain a hydrogen flame without the hydrogen and oxygen being "over-pressured" relative to the ambient and coming from a rocket nozzle.

http://ruc.noaa.gov/AMB_Publications_bj/2009%20Schlatter_Atmospheric%20Composition%20and%20Vertical%20Structure_eae319MS-1.pdf

But this is cheating, because we know we are going to "drop" the X-15 vehicle a bit before climbing again. I'm inclined to tale a look at the UFL figures, because I imagine that a breached hydrogen gas bag presents a "fuel rich" mixture in the atmosphere presumably at risk of ignition at very low pressures. So I'm looking for Hydrogen UFL at altitudes above the stratosphere.

I'm kind of tired right now, as it's well past midnight ... let me sleep on it a bit   

(theres no "tired smiley face?)

[Miranda.T]

Expanding on the idea of SSO... For those with access to UK television, Channel 4 this Sunday at 8 pm (GMT) has a documentary about the World War 2 'super gun' with the mechanism of multistage acceleration which I though might be used for launching a capsule.

For the airship launch, I've been mulling over the idea of two airships arranged parallel to each other and joined by a framework incorporating a steam or compressed air launching rail; this rail would arc up at the end to launch the rocket-plane upwards (a little like the 'ski-jump' used on UK aircraft carriers to launch Harriers). Then the rocket-plane could be launched to a safe distance from the airships before rocket ignition but also be on an upwards trajectory.

Yours,
Miranda.

[J. Wilhelm]

Expanding on the idea of SSO... For those with access to UK television, Channel 4 this Sunday at 8 pm (GMT) has a documentary about the World War 2 'super gun' with the mechanism of multistage acceleration which I though might be used for launching a capsule.

For the airship launch, I've been mulling over the idea of two airships arranged parallel to each other and joined by a framework incorporating a steam or compressed air launching rail; this rail would arc up at the end to launch the rocket-plane upwards (a little like the 'ski-jump' used on UK aircraft carriers to launch Harriers). Then the rocket-plane could be launched to a safe distance from the airships before rocket ignition but also be on an upwards trajectory.

Yours,
Miranda.

Sounds interesting, but I wonder if it is necessary to have a catapult or launch rail at all... If I understand correctly your preoccupation is with the rocket plume hitting the gas bag.  A missile or any rocket dropped from a relatively slow moving vehicle basically poses no threat to the launching pad, provided it is allowed to drop for a small distance before firing the rocket.  How many tens or hundreds of feet of altitude would be lost upon dropping the rocket before it is ignited?

[Peter Brassbeard]

My latest creation.

... having a hard time finding a test pilot.

[J. Wilhelm]

My latest creation.

... having a hard time finding a test pilot.

Don't look at me, man.  I just dream them up. The closest I ever came to fly was on that Cessna 150 flight simulator in college. The last time I was on one, I nearly broke it...

I was supposed to do a test run for a high power climb, a maximum range glide, several turns, and other flight mission phases, while two team mates gathered data for the Flight Dynamics laboratory class.  Strictly matching physics to experimental data based on engine size, wing size, power settings, etc.  This is just Isaac Newton's stuff, really simple maths, more like High School physics applied to the dynamics of an airplane, actually a fun class.

However, my two team mates, a guy and a girl, were like misbehaving monkeys when they were together, and at that time they decided to pull a prank on me, right after I levelled off from the climb. Once I was in cruise, they messed with every single control and cranked up the turbulence and crosswinds to the maximum allowable.

While I was trying to keep the craft level, with the controls at my hand shaking like I had a really bad case of Parkinson's disease, I heard over my shoulder, in a real condescending tone of voice: "Stop shaking the stick like that. What's the matter John? Haven't you ever flown before?"  Then the pair started laughing while the plane was on a steep dive. I didn't even know how to get off the damn machine 

[Peter Brassbeard]

GAAAAAAH!  google messed me up again.

[J. Wilhelm]

 

Interesting.  It's actually been done in the small drone category. Alas,  as the size of the craft gets bigger, you might find it becomes exponentially more difficult. A little gremlin by the name of Strouhal Number is responsible for that. The larger a wing is,  the slower it must flap to be efficient,modified also by the forward speed. Has to do with recycling lost energy from each flap by "back slapping" the outgoing vortex of air a second time in the right way to recover lost energy.  Through evolution,  animals developed the right flapping frequency. Compare insects and humming birds to condors,  for example.

[Khem Caigan]

Anyway, my thoughts on Steampunk supersonic flight. As shown in your picture, a bullet shape is nice and stable (if spinning) in flight, so let's go Jules Verne (or possibly Gerald Bull - https://en.wikipedia.org/wiki/Gerald_Bull) and do a sub-orbital by putting our passengers in a glorified shell. But what of the problem of squishing them to a thin red smear by the launch force? Well, I was watching a documentary a little while ago about one of Hitler's V-weapons that never saw service - a supergun that would have used staged explosions along the launch tube to accelerate the projectile. So, I'm thinking a massive launch tube (laid along the side of some convenient mountain), our intrepid aeronaut's capsule accelerated at multiple stages to keep down to say 4g max. I'll have to play with some numbers when I get a few moments to see if it might be feasible.

Yours,
Miranda.

We actually had some discussion of "space guns" back in 2009.
Five Gs is punishingly uncomfortable for humans, but considered
tolerable for about six minutes.

In other words - you might very well feel that you are about to
die but, likely as not, you will survive the experience.

Humans have been briefly exposed to as much as ten Gs and
survived.

[Captain]

http://science.howstuffworks.com/transport/flight/modern/physics-of-flight-quiz.htm?mkcpgn=i600000603&utm_source=facebook.com&utm_medium=social&utm_campaign=hswaccount

[Khem Caigan]

I recently came across this article :

Silanes as Fuel for Aerospace Propulsion
By Domenico Simone, Claudio Bruno and Bernhard
Hidding

- in :

Transactions of the Japan Society for Aeronautical
and Space Science, Space Technology
Vol. 7 (2009) No. ists26
(ISTS Special Issue: Selected papers from the 26th
International Symposium on Space Technology and
Science)
Pages 33-39.
(View / Download .PDF )
http://tinyurl.com/guhfc38

The keywords were :

Liquid Rockets,
Air-breathing Engines,
High Energy Density Fuel

Further rummaging hit upon the following pages :

Spoiler: ShowHide

Peter Plichta's One Stage Rocket Disc
@NASA Spaceflight . com
http://tinyurl.com/pgphzwx

" In 1933 the chemist Alfred Stock published his
book Hydrides of Boron and Silicon in the United
States. During and following the First World War
he worked at the Technische Hochschule in Karlsruhe,
Germany and showed that silicon-hydrogen compounds
could be synthesized. Because the element silicon
is listed in the periodic table below the element
carbon, this result was actually expected. Stock
managed to reach a chain length of 4 silicon atoms,
with the first two silanes being gaseous, the third
and fourth liquid. All these silanes are very highly
prone to self-ignition.

In 1970 Peter Plichta disproved the textbook theory
that the higher silanes are unstable. One of his
achievements was to create a mixture of silanes with
the chain lengths 5 to 10 (Si5H12 to Si10H22). He
also managed to separate the oil into the individual
silanes by means of gas chromatic analysis. This
showed the surprising result that silanes with a
chain length of over 7 silicon atoms will no longer
ignite spontaneously and can thus be used for
commercial purposes. . .

It has been known since 1924 that nitrogen at a
temperature of 1400°C reacts with powdered
silicon to form silicon-nitride while emitting heat.
This material can resist temperatures of up to
1900°C, indicating a very high bonding strength
in the molecule. In contrast to silicon, carbon
atoms cannot burn for reasons of quantum
mechanics, which means that rocket fuel such
as kerosene, liquid hydrogen and hydrazine in
an air-breathing engine can do nothing with the
80% nitrogen contained in the air but agitate
it through the engine. . .

Peter Plichta got the idea of constructing a disc in
which jet-turbines attached to shafts would drive two
ring-shaped blade rings rotating in opposite directions.
This will cause the disc to be suspended by the air just
like a helicopter. The craft can then be driven sideways
by means of a drop-down rocket engine. When a speed of
over 200 km/h has been reached, the turbines for the
blade rings will be switched off and covered to enhance
the aerodynamic features of the shape. The craft will
now be borne by the up-draft of the air, just like an
aircraft is. This will also mean that the critical power
required for rocket ascent will not be necessary. When
the spacecraft is orbiting the planet, the N2/O2 mixture
of the air will first be fed in through a drop-down air
intake when the craft is still at a low altitude of 30
km (1% air pressure). This will be conducted to the
rocket motor and the craft will thus accelerate to a
speed of 5000-8000 km/hour. This is where a standard
rocket jettisons its first stage, because by then about
75% of the fuel has already been used up.

The disc on the other hand will continue to accelerate
to 20,000 km/h and will thus reach an altitude of approx.
50 km (1 per thousand of air pressure). The speed will
increase as the air pressure drops, so that the process
can be continued until an altitude of approx. 80
kilometres and 25,000 km/h can be maintained. In
order to reach the required speed of 30,000 km/h and
an altitude of around 300 km, only a single measure
of oxidation agent will be needed at the end.

In the hot combustion chamber silanes decompose
spontaneously into hydrogen and silicon radicals.
The hydrogen is burned by the oxygen in the air and
water formed. Because molecular nitrogen is very tightly
bonded, it must be preheated and subject to catalytic
dissociation. The extremely hot silicon radicals will
provide additional support for this process, which will
in turn lead to silicon nitride (Hf = -750 kJ) being
formed. In order to burn superfluous nitrogen, larger
amounts of Mg, Al or Si powder can be added to the
silane oil.

When the spacecraft is returning from space the
ceramic-protected underside of the disc will brake its
speed to approximately 500 km/h and the covering will
open again, while the blade rings will automatically
begin to rotate. The jet turbines will then be started
for the landing operation. "

Some slick YouTube presentations in German follow,
with scathing ( and occasionally on-point ) commentary
from the Forum members.

Complaints about the greater part of Plichta's work
only being available in German aside, I would be
interested in knowing how his long-chained liquid
silane fuel "doped" with powdered metals perform in
comparison with conventional rocket fuels such as
kerosene and hydrazine, and what ( if any ) chance
there is of seeing long-chained liquid silane-fueled
engines on our highways in the near future.

[ Edit 1/2/2016 : The articles also mention
silicon nitride as a by-product of combustion.
That may be well and good for purposes of
rocketry, but can we expect any crust or
scale accumulation in a turbine or some
other engine burning liquid silanes for
fuel? ]

Miethe provided the inspiration for Plichta's
craft, and you'll find a description of
Plichta's vehicle at the bottom of the page
below :

Miethe Elektrische Luft Turbine
Unmanned V-7
by Rob Arndt
http://tinyurl.com/hc7594f

Turning Sand into Fuel
- Silicon Oil as an Energy Carrier
@ Hasselberger . com
http://tinyurl.com/y8qrwyk

Note :

You need to sign up to view the patents
available on FreePatentsOnline.

Signing up is free, and I happen to like
the search engine at FPO better than that
of the USPTO or that of GooglePatents.

Below are a few links to the relevant patents :

Method and Apparatus for Operating
a Gas Turbine with Silane Oil as Fuel
United States Patent 5996332
Inventor: Peter Plichta, Dusseldorf, Germany
Assignee: Klaus Kunkel, Ratingen, Germany
Filed: 01/30/1998
Published: 12/07/1999

Abstract :

The invention relates to a method of driving a
shaft by reaction of silanes, preferably silane
oils, with air in a double combustion chamber and
an associated drive mechanism.

The hydrogen of the silanes reacts in the first
combustion chamber with an insufficient level of
oxygen of the air supplied, thereby producing high
temperatures.

At said high temperatures, the nitrogen from the
air supplied reacts with the silicon of the silane
to form silicon nitride.

The resultant combustion gases and dust and the
non-combusted hydrogen are mixed in the second
combustion chamber with a large quantity of cold
compressed air, the hydrogen undergoing late burning,
and they subsequently enter a turbine chamber to
actuate turbine blades connected to a shaft.

The method is particularly environmentally-friendly
since no toxic or polluting waste gases are produced.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/htyo6j5
===================
Reusable Spacecraft
Inventors: Peter Plichta; Walter Buttner,
both of Dusseldorf, Germany.
Assignee: Klaus Kunkel, Dusseldorf, Germany
United States Patent 5730390
Filed: 11/13/1995
Published: 03/24/1998

Abstract :

A reusable space craft having a disk-shaped casing
which receives buoyancy upon horizontal travel through
a gas atmosphere and three drive systems on the casing.

A first drive system utilizes counter-rotating rotors
driven by jet engines on the periphery. A second drive
system utilizes a rocket rotor which can swing out from
the bottom of the casing into an inclined position. The
third drive system is a main thruster rocket at the center
of the bottom fueled by an Si5 to Si9 silane propellant.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/z8mcygo
==========================
Discus-Shaped Aerodyne Vehicle for Extremely
High Velocities
United States Patent 5836543
Inventors; Klaus Kunkel, HerbartStrasse 6A,
D-40882, Ratingen; Peter Plichta,
Dusseldorf, both of Germany
Assignee: Klaus Kunkel, Ratingen, Germany
Filed: 08/01/1996
Published: 11/17/1998

Abstract :

A discus-shaped aircraft is provided with a peripheral
jet arrangement for generating lift and, in the bottom
of the aircraft, at least one rocket engine supplied
with silicon hydride and compressed air and operated
under conditions in which the silicon hydride is reacted
with nitrogen of the compressed air to form silicon
nitride while the nitrogen of the silicon hydride
compounds reacts with oxygen to form H2O.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/jtjhxxh
===========================
Process for Operating a Reaction-Type Missile Propulsion
System and Missile Propulsion System
United States Patent 5775096
Inventor: Peter Plichta, Bruhnstrasse 6a,
D-40225 Dusseldorf. Germany
Filed: 07/18/1996
Published: 07/07/1998

Abstract :

A method for accelerating a vehicle in the atmosphere,
space or aerospace includes the steps of supplying a
propellant having silicone hydride compounds into a
combustion chamber, compressing air and delivering
compressed air into a ring formed with a plurality of
circumferential orifices which open into the combustion
chamber, reaching thereby temperatures of about 3000°C.
cracking nitrogen molecules present in the air at the
temperature which attack the silicon atoms to generate
great mass.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/zb3vzz2
===========================

[J. Wilhelm]

I recently came across this article :

Silanes as Fuel for Aerospace Propulsion
By Domenico Simone, Claudio Bruno and Bernhard
Hidding

- in :

Transactions of the Japan Society for Aeronautical
and Space Science, Space Technology
Vol. 7 (2009) No. ists26
(ISTS Special Issue: Selected papers from the 26th
International Symposium on Space Technology and
Science)
Pages 33-39.
(View / Download .PDF )
http://tinyurl.com/guhfc38

The keywords were :

Liquid Rockets,
Air-breathing Engines,
High Energy Density Fuel

Further rummaging hit upon the following pages :

Spoiler: ShowHide

Peter Plichta's One Stage Rocket Disc
@NASA Spaceflight . com
http://tinyurl.com/pgphzwx

" In 1933 the chemist Alfred Stock published his
book Hydrides of Boron and Silicon in the United
States. During and following the First World War
he worked at the Technische Hochschule in Karlsruhe,
Germany and showed that silicon-hydrogen compounds
could be synthesized. Because the element silicon
is listed in the periodic table below the element
carbon, this result was actually expected. Stock
managed to reach a chain length of 4 silicon atoms,
with the first two silanes being gaseous, the third
and fourth liquid. All these silanes are very highly
prone to self-ignition.

In 1970 Peter Plichta disproved the textbook theory
that the higher silanes are unstable. One of his
achievements was to create a mixture of silanes with
the chain lengths 5 to 10 (Si5H12 to Si10H22). He
also managed to separate the oil into the individual
silanes by means of gas chromatic analysis. This
showed the surprising result that silanes with a
chain length of over 7 silicon atoms will no longer
ignite spontaneously and can thus be used for
commercial purposes. . .

It has been known since 1924 that nitrogen at a
temperature of 1400°C reacts with powdered
silicon to form silicon-nitride while emitting heat.
This material can resist temperatures of up to
1900°C, indicating a very high bonding strength
in the molecule. In contrast to silicon, carbon
atoms cannot burn for reasons of quantum
mechanics, which means that rocket fuel such
as kerosene, liquid hydrogen and hydrazine in
an air-breathing engine can do nothing with the
80% nitrogen contained in the air but agitate
it through the engine. . .

Peter Plichta got the idea of constructing a disc in
which jet-turbines attached to shafts would drive two
ring-shaped blade rings rotating in opposite directions.
This will cause the disc to be suspended by the air just
like a helicopter. The craft can then be driven sideways
by means of a drop-down rocket engine. When a speed of
over 200 km/h has been reached, the turbines for the
blade rings will be switched off and covered to enhance
the aerodynamic features of the shape. The craft will
now be borne by the up-draft of the air, just like an
aircraft is. This will also mean that the critical power
required for rocket ascent will not be necessary. When
the spacecraft is orbiting the planet, the N2/O2 mixture
of the air will first be fed in through a drop-down air
intake when the craft is still at a low altitude of 30
km (1% air pressure). This will be conducted to the
rocket motor and the craft will thus accelerate to a
speed of 5000-8000 km/hour. This is where a standard
rocket jettisons its first stage, because by then about
75% of the fuel has already been used up.

The disc on the other hand will continue to accelerate
to 20,000 km/h and will thus reach an altitude of approx.
50 km (1 per thousand of air pressure). The speed will
increase as the air pressure drops, so that the process
can be continued until an altitude of approx. 80
kilometres and 25,000 km/h can be maintained. In
order to reach the required speed of 30,000 km/h and
an altitude of around 300 km, only a single measure
of oxidation agent will be needed at the end.

In the hot combustion chamber silanes decompose
spontaneously into hydrogen and silicon radicals.
The hydrogen is burned by the oxygen in the air and
water formed. Because molecular nitrogen is very tightly
bonded, it must be preheated and subject to catalytic
dissociation. The extremely hot silicon radicals will
provide additional support for this process, which will
in turn lead to silicon nitride (Hf = -750 kJ) being
formed. In order to burn superfluous nitrogen, larger
amounts of Mg, Al or Si powder can be added to the
silane oil.

When the spacecraft is returning from space the
ceramic-protected underside of the disc will brake its
speed to approximately 500 km/h and the covering will
open again, while the blade rings will automatically
begin to rotate. The jet turbines will then be started
for the landing operation. "

Some slick YouTube presentations in German follow,
with scathing ( and occasionally on-point ) commentary
from the Forum members.

Complaints about the greater part of Plichta's work
only being available in German aside, I would be
interested in knowing how his long-chained liquid
silane fuel "doped" with powdered metals perform in
comparison with conventional rocket fuels such as
kerosene and hydrazine, and what ( if any ) chance
there is of seeing long-chained liquid silane-fueled
engines on our highways in the near future.

[ Edit 1/2/2016 : The articles also mention
silicon nitride as a by-product of combustion.
That may be well and good for purposes of
rocketry, but can we expect any crust or
scale accumulation in a turbine or some
other engine burning liquid silanes for
fuel? ]

Miethe provided the inspiration for Plichta's
craft, and you'll find a description of
Plichta's vehicle at the bottom of the page
below :

Miethe Elektrische Luft Turbine
Unmanned V-7
by Rob Arndt
http://tinyurl.com/hc7594f

Turning Sand into Fuel
- Silicon Oil as an Energy Carrier
@ Hasselberger . com
http://tinyurl.com/y8qrwyk

Note :

You need to sign up to view the patents
available on FreePatentsOnline.

Signing up is free, and I happen to like
the search engine at FPO better than that
of the USPTO or that of GooglePatents.

Below are a few links to the relevant patents :

Method and Apparatus for Operating
a Gas Turbine with Silane Oil as Fuel
United States Patent 5996332
Inventor: Peter Plichta, Dusseldorf, Germany
Assignee: Klaus Kunkel, Ratingen, Germany
Filed: 01/30/1998
Published: 12/07/1999

Abstract :

The invention relates to a method of driving a
shaft by reaction of silanes, preferably silane
oils, with air in a double combustion chamber and
an associated drive mechanism.

The hydrogen of the silanes reacts in the first
combustion chamber with an insufficient level of
oxygen of the air supplied, thereby producing high
temperatures.

At said high temperatures, the nitrogen from the
air supplied reacts with the silicon of the silane
to form silicon nitride.

The resultant combustion gases and dust and the
non-combusted hydrogen are mixed in the second
combustion chamber with a large quantity of cold
compressed air, the hydrogen undergoing late burning,
and they subsequently enter a turbine chamber to
actuate turbine blades connected to a shaft.

The method is particularly environmentally-friendly
since no toxic or polluting waste gases are produced.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/htyo6j5
===================
Reusable Spacecraft
Inventors: Peter Plichta; Walter Buttner,
both of Dusseldorf, Germany.
Assignee: Klaus Kunkel, Dusseldorf, Germany
United States Patent 5730390
Filed: 11/13/1995
Published: 03/24/1998

Abstract :

A reusable space craft having a disk-shaped casing
which receives buoyancy upon horizontal travel through
a gas atmosphere and three drive systems on the casing.

A first drive system utilizes counter-rotating rotors
driven by jet engines on the periphery. A second drive
system utilizes a rocket rotor which can swing out from
the bottom of the casing into an inclined position. The
third drive system is a main thruster rocket at the center
of the bottom fueled by an Si5 to Si9 silane propellant.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/z8mcygo
==========================
Discus-Shaped Aerodyne Vehicle for Extremely
High Velocities
United States Patent 5836543
Inventors; Klaus Kunkel, HerbartStrasse 6A,
D-40882, Ratingen; Peter Plichta,
Dusseldorf, both of Germany
Assignee: Klaus Kunkel, Ratingen, Germany
Filed: 08/01/1996
Published: 11/17/1998

Abstract :

A discus-shaped aircraft is provided with a peripheral
jet arrangement for generating lift and, in the bottom
of the aircraft, at least one rocket engine supplied
with silicon hydride and compressed air and operated
under conditions in which the silicon hydride is reacted
with nitrogen of the compressed air to form silicon
nitride while the nitrogen of the silicon hydride
compounds reacts with oxygen to form H2O.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/jtjhxxh
===========================
Process for Operating a Reaction-Type Missile Propulsion
System and Missile Propulsion System
United States Patent 5775096
Inventor: Peter Plichta, Bruhnstrasse 6a,
D-40225 Dusseldorf. Germany
Filed: 07/18/1996
Published: 07/07/1998

Abstract :

A method for accelerating a vehicle in the atmosphere,
space or aerospace includes the steps of supplying a
propellant having silicone hydride compounds into a
combustion chamber, compressing air and delivering
compressed air into a ring formed with a plurality of
circumferential orifices which open into the combustion
chamber, reaching thereby temperatures of about 3000°C.
cracking nitrogen molecules present in the air at the
temperature which attack the silicon atoms to generate
great mass.

Free to Read / Download
@ FreePatentsOnline
http://tinyurl.com/zb3vzz2
===========================

Thank you for posting this Mr.  Caigan.   I've started reading the article on the silane based LR fuel. They start by taking advantage of lower temperatures for  complex silane molecule decomposition and wider liquid temperature ranges (for compact storage),  with an additional storage of energy due to positive enthalpy of formation, and then wrap it all up the claim that there are no dangerous radicals from combustion (not sure if I believe that. Fast combustion is a very messy process, chemically speaking),  but it looks interesting.

So far from what I gather they are basically claiming that fuel-rich mixtures above stoichiometric (equivalence ratio of 1) tend to give very high specific impulse (thrust efficiency) over a wider range of fuel rich mixtures; ie this fuel "likes" rich fuel mixtures and can operate well for a number of rich fuel-air ratios, whereas hydrocarbons drop their efficiency sharply when you are even a bit above a stoichiometric mixture (equivalence ratio of 1), and doing it with lower combustion temperatures.  Because energy is needed to form (manufacture) the complex silanes, when these break down in combustion, they return some of the energy you used in making the molecules in the first place.

So basically you can use lighter engines with the lower temperatures and the energy density of the fuel is higher, for smaller fuel tanks, if I understand correctly.  Practically for the engines, if indeed the combustion temperatures are lower, and the fuel remains liquid over a greater temperature range, then you can avoid having to circulate liquid hydrogen with pumps on the bell, or at least your pumps can be smaller, and your rocket nozzle bells lighter both by material and cooling pump size.  

That is one of the reasons that the Russians have been successful with their rocket technology, because they advanced bi-propellant technology and their rockets operate at lower temperatures, saving weight. When I was in graduate school, the analytical theory books on combustion were actually written in Russian (!).  Believe it or not, the Russian were slightly ahead of us in combustion at the end of the Cold War, and to avoid getting those rocket engines into unfriendly hands, out own government took to buying the Russian engines for some of our own military systems.  Now the Russians don't like us, and so we have to finish developing our rocket technology and why not?  Developing a new fuel technology might help a lot....

Good idea to reduce the weight of those nozzles and increase the specific impulse.  Pair that with aerospike technology and you get an engine that can operate at a greater number of altitudes and be more forgiving about the specific fuel mix ratios - all of it leading to a greater overall efficiency in propulsion.

Now the $64000 question is: How expensive is it going to be to develop the infrastructure to develop silane fuels?

[Khem Caigan]

Now the $64000 question is: How expensive is it going to be to develop the infrastructure to develop silane fuels?

It looks to me rather as if the infrastructure
is already in place. And, predictably, the bulk
of the larger, long-chain silanes are already
being produced in China.

First dibs on all that Helium-3 on the Moon,
and suchlike.

Silane Production Unit

" GT Advanced Technologies offers a complete
silane production unit designed as a
standalone facility to produce VLSI grade
silane for semiconductor and solar markets.

GT's silane production plant is constructed
using efficient structural modules that
decrease site work and reduce installation
time. The silane production module, which
includes work practice control and
standardization, provides flexibility
through scalability to speed start-up while
lowering cost. GT's silane production module
can begin delivering quality silane within
24 months. "

@ GT Advanced Technologies . Com
http://tinyurl.com/gq9cge8

" This report presents data on the current
silane market. Published and public
information on 22 preparative methods for
monosilane and higher silanes are reviewed.

...The silane process developed by Union
Carbide Corporation under the DOE/JPL
Flat-Plate Solar Array Project is summarized,
including the purification
steps.

A section on the status of silanes in Japan
is also included. "

( Download .PDF @ Nrel . Gov )
http://tinyurl.com/j3n2lbm

Chemical Book
Pentasilane

Global Suppliers :

T&W GROUP CHINA
Shanghai Gileader Advanced Material Technology Co.,Ltd CHINA
Chizhou Kailong Import and Export Trade Co., Ltd. CHINA

@ Chemical Book . Com
http://tinyurl.com/hkxqacg

[Khem Caigan]

A few more articles of related interest :

New Approach for Single Stage Ascent to Orbit :
Silicon Based Fuels for Space Flight
by David Padanyi-Gulyas and Andras D. Bodo
Nitronics Aerospace Technologies, LLC
2005-01-3412
( .PDF @ Academia . Edu )
http://tinyurl.com/zve48su

See also :

Polysilanes : all-rounder base materials in
PhotoVoltaics
City Solar Technologie GmbH & Co. KG
Bitterfeld-Wolfen, Nov 15, 2007
( .PDF downloadable here : )
http://tinyurl.com/zjm5tbt

Let me preface this by saying that I have no
proprietary interest in City-Solar whatsoever
- I am providing this link as an example of the
sort of mischief that folks are already getting
up to with polysilanes out there in the market
place, and with a mind toward benchmarking
just how much progress has been made toward
providing the buckets of polysilanes necessary
to create and support sustainable orbital and
/ or lunar factories.

This company was founded in 2003, and they
have been up-scaling their production facilities
ever since.

They are in the business of producing photovoltaic
"solar panels", and they are developing liquid
polysilanes as the "enabling technology" for
"Printable electronics" and "Electronic precursors".

Example : Seiko Epson

Solution-processed silicon films and transistors
Nature 440, pages 783-786,
April 6, 2006
http://tinyurl.com/zv9dbg3

Printed Electronics at Seiko Epson
@ Printed electronics World . Com
http://tinyurl.com/hx3t8vd

" It has already been demonstrated that silicon
based devices can be produced from H-Silanes
with ink jet or spin coating processes.

This could revolutionize the production technology
of many electronic devices, if it would be possible
to produce the required amount of these silanes at
competitive cost. "

Si5H10 cyclo-Pentasilane is described in their
brochure as a "potentially disrupting new Si-coating
technology".

Back in the day, something "potentially disrupting"
was simply referred to as "revolutionary".

Cyclopentasilane Si5H10 is dissolved in Toluol and
used in both inkjet and spin coating for printed
electronics, which looks to be much simpler than
conventional photolithographic technology.

City Solar-Technology claims that they are capable
of producing the required silanes at competitive
costs with their plasma polymerization procedure,
or "Plasma-Polysilane technology" ( they employ
microwaves ).

I gather from the brochure that they are well-aware
of the potential of polysilanes as fuel but, at the
time this brochure was printed, they were unable
to produce enough material to address the needs
of that market.

Still, it is encouraging that high-demand products
such as "solar cells" and "microchips", are going to
require polysilanes in their production.

[J. Wilhelm]

Let me preface this by saying that I have no
proprietary interest in City-Solar whatsoever

Are you sure there is no "Khem Caigan Industries, Ltd." out there?   

"Taking Khemistry to the next level"

[Khem Caigan]

Are you sure there is no "Khem Caigan Industries, Ltd." out there?   

"Taking Khemistry to the next level"

Apart from my duties as Curator of the Harry Everett
Smith Library, I am also the CEO and Chief Cook and
Bottle Washer at ZAPGARDEN.

But our remit is Electrometeorology, Perfumes, Paint
and Metallurgy.

Mostly

I was booted off of Do-It-Yourself Drones years ago
because I was recommending construction materials
that were suitable for hard vacuum.

Now we have "off-the-shelf' electromagnetic tethers
and ion engines in kit form that kids can install in
their CubeSats.

I expect that it won't be all that long until kids are
launching their own 3D Printers and Factory Bots
out to near-Earth asteroids and assembling their
own spaceplanes out of foamed metals and
such-like materials. And operational habitats /
refueling stations into the bargain.

And if some of those habs are decked out with
miles of brassy conduit and lots of wood veneer,
so much the better!

Hasten The Day!

[Peter Brassbeard]

I was booted off of Do-It-Yourself Drones years ago
because I was recommending construction materials that were suitable for hard vacuum.

(raises an eyebrow) What materials, pray tell, were they objecting to, and for what application?

[Khem Caigan]

I was booted off of Do-It-Yourself Drones years ago
because I was recommending construction materials that were suitable for hard vacuum.

(raises an eyebrow) What materials, pray tell, were they objecting to, and for what application?

I recollect one post was about TEEK-H polyimide foam
used in aerogel composites for thermal insulation, and
another was about the Clevios (TM) PH1000 transparent
conductive polymer.

The idea was to provide a 'heads up' on Materials Of
Interest for folks that wanted to build drones capable of
withstanding the environment in Nearspace, LEO and GEO.

This was back in 2009. And it is all "Old Hat" these days
for folks assembling their own CubeSats, MicroSats and
NanoSats, &tc.

[J. Wilhelm]

Breaking news:

Sierra Nevada Corporation's Dream Chaser mini-shuttle has been chosen as the third personnel and cargo vehicle to re-supply the International Space Station.

http://www.bbc.com/news/science-environment-35328544

The European Space Agency (Esa) says it is excited by its US counterpart's selection of a winged vehicle to resupply the space station. Nasa has extended contracts to existing commercial cargo carriers, Orbital ATK and SpaceX, but has added a third team: the Sierra Nevada Corporation (SNC). This new entrant wll fly an automated mini-shuttle called Dream Chaser.
Esa has agreements to co-operate with SNC, which should now lead to European companies providing components. Chief among these contributions will be the International Berthing and Docking Mechanism (IBDM) - a new system developed in Europe to join spacecraft together.

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

The Dream Chaser is an American reusable crewed suborbital and orbital[6] lifting-body spaceplane being developed by Sierra Nevada Corporation (SNC) Space Systems. The Dream Chaser is designed to carry up to seven people to and from low Earth orbit. The vehicle would launch vertically on an Atlas V rocket and land horizontally autonomously on conventional runways

Ugly little critter, isn't it?  I guess loveable like a bulldog   The actual orbiter will not have the Pitot probe "arbor" on the nose like this atmospheric flight test vehicle shows. There is interest from European companies to upgrade the design to a folding wing design that will allow the orbiter to fit in a cargo fairing used for the Ariane rocket, and other US launch vehicles. It is thought that there will be US and European versions of the craft. The original design called for the orbiter to be launched without protection on top of an Atlas V rocket.

The selection doesn't come without controversy, and it appears to have been the product of a drama worthy of a "soap opera" or "telenovella" plot:

Spoiler: ShowHide

2014 CCtCap non-selection by NASA

After being involved with the NASA Commercial Crew Development program since 2009—and being selected as one of the contract award recipients in each prior phase of the program—NASA did not select the Dream Chaser for the next phase of the Commercial Crew Program announced 16 September 2014[50] due to lack of maturity.[51] Sierra Nevada filed a protest to the US Government Accountability Office (GAO) on 26 September. The GAO is investigating and will respond after a process that could take up to 100 days. Boeing and SpaceX were asked by NASA to "stop work" on the crewed spacecraft during the protest resolution.[52] However, on 22 October 2014, a Federal Judge ruled that NASA could proceed with contracts with Boeing and SpaceX to develop their "space taxis", while the GAO continued to consider Sierra Nevada's protest of NASA's original decision.[53]

Two weeks after losing the Commercial Crew Transportation Capability (CCtCap) competition to SpaceX and Boeing on 16 September 2014,[54] Sierra Nevada Corporation announced it has designed a launch system that combines a scale version of the company's Dream Chaser space plane with the Stratolaunch Systems air launch system.[55] Earlier the same week, Sierra Nevada introduced new spaceflight opportunities to the world - coined the Dream Chaser Global Project"- which would provide customized access to low Earth orbit to global customers.[56]
Despite not being selected to continue forward under NASA's Commercial Crew transportation Capability (CCtCap) phase of the effort to send crews to orbit via private companies, SNC is still completing milestones under earlier phases of the CCP.[57] On 2 December 2014 SNC announced that it completed NASA's CCiCap Milestone 5a related to propulsion risk reduction for the Dream Chaser space system.[58]

By late December, details had emerged that "a high-ranking agency official"—"William Gerstenmaier, the agency's top human exploration official and the one who made the final decision"—"opted to rank Boeing's proposal higher than a previous panel of agency procurement experts." More specifically, Sierra Nevada asserted in their filings with the GAO that Gerstenmaier may have "overstepped his authority by unilaterally changing the scoring criteria."[59]

On 5 January 2015, the GAO denied Sierra Nevada's CCtCap challenge, stating that NASA made the proper decision when it decided to award Boeing $4.2 billion and SpaceX $2.6 billion to develop their vehicles. Ralph White, the GAO's managing associate counsel, announced that NASA "recognized Boeing's higher price but also considered Boeing's proposal to be the strongest of all three proposals in terms of technical approach, management approach and past performance, and to offer the crew transportation system with most utility and highest value to the government." Furthermore, the agency found "several favorable features" in SNC's proposal "but ultimately concluded that SpaceX's lower price made it a better value."

I'm not exactly sure what exactly led to that decision being possibly reversed, or perhaps a change of heart by NASA during the year between January 5 2015 and yesterday January 15 2016

~ ~ ~

J. Wilhelm

[Khem Caigan]

My hope still lies with the amateur rocketry community
that continues to "push the envelope" out in the deserts,
lobbing their designs ever higher into orbit.

Really, all we need is an upgraded, Open Source version
of something like the old Titan II to give Rocketry Clubs
and/or Universities a crack at re-booting what used to be
called "the Space Race" - which has ( sadly ) devolved
into something rather more like watching paint dry.

zzzzZZZZzzzzzZZZzzzzz<snork>zzzzzZZZZzzzzz. . . .

[ Note to Sinter Klaas : A single-stage rocket with a
tankful of hexasilane and a supplementary tankful of LOX
to keep things perking along in vacuum would be nice. ]

Space Tourism: Regulating Passage
to the Happiest Place Off Earth
by Catherine E. Parsons
( Download .PDF @ Chapman Dot Edu )
http://tinyurl.com/jpvs9t8

A Few Dreamers Building Rockets in Workshops
by Preston Lerner
Popular Science, May 2003
( Free Preview @ GoogleBooks )
http://tinyurl.com/zlaqe8k

Amateur Rocketeers Chase $10,000 Launch
Prize Offered by John Carmack
By Mike Wall, October 11, 2011
@ Space Dot Com
http://tinyurl.com/o7se3s9

The Mojave Launch Lab :
A Community of Alternative Rocketeers
Who May One Day Dominate The Space Biz
by Stephen Joiner
-in-
Air & Space, April/May 2011
( Download .PDF & Friends Of Amateur Rocketry Dot Org )
http://tinyurl.com/jnbhcjg

Carbon Origins :
From Hobbyist Rockets to a Space Tech Business
By Nathan Hurst
July 21, 2015
Make Magazine Dot Com
http://tinyurl.com/otere7e

"Interplanetary travel is now the only form
of 'conquest and empire' compatible with
civilisation. Without it, the human mind,
compelled to circle forever in its planetary
goldfish bowl, must eventually stagnate."

- Arthur C. Clarke, Voices From The Sky, page 12.
Pyramid Books, 1965.

[J. Wilhelm]

I did get to play with model rockets as a kid.  The thing is,  I was never satisfied with it.  Thankfully I never tried some of the more dangerous ideas I had    Otherwise you'd be calling me "crispy"  or "stumpy"

[J. Wilhelm]

If you pardon the very cheesy 1980's Rambo-style music, I just found this video from Sierra Nevada Corp.showing a computer animation of a typical mission to the International Space Station. It looks like the docking module will be disposable.

SNC's Dream Chaser® Cargo System: A Transportation System to Deliver Cargo to the ISS for NASA


From Geek Wire: http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

The Dream Chaser is designed to be launched atop an Atlas 5 rocket, with its wings in a folded-up configuration for orbital deployment. The cargo version will be equipped with an unpressurized "trunk" in the back. The spaceship should be capable of carrying more than 5 tons of cargo to the space station. It's also expected to deliver payloads from orbit to NASA in just a few hours, touching down with a smooth runway landing.

That quick and gentle delivery method is one reason why the Dream Chaser is due to be added to NASA's cargo fleet of SpaceX and Orbital ATK space vehicles, starting in late 2019. The space station program's chief scientist, Julie Robinson, said that feature is attractive for handling biological samples from space – potentially including live experimental animals.

"It would be effectively like we're an airline. We own the Dream Chasers."

The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there's a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.

Sirangelo said two Dream Chaser space planes will be built for NASA's use – and maybe not just for NASA.

"It would be effectively like we're an airline," he explained. "We own the Dream Chasers. NASA is our priority client, so they would get priority use of the vehicle. However, when they're not using them, and as long as it doesn't interfere, we have the capability of using the same vehicles for other clients."

Those clients could include other space agencies that want to pursue their own orbital research programs, with or without access to the space station. And the Dream Chaser's basic design can be adapted to accommodate a crew rather than cargo.

For now, SNC is focusing on the cargo-only version, but Sirangelo said customers will eventually be able to choose from a wide range of Dream Chaser options.

"It's very similar to how an aircraft manufacturer like Boeing or Airbus plans their vehicles," he said. "They have a core vehicle built for the 747 or the Airbus 330 or 320. And they can have different missions for the same airframe. It could be a passenger vehicle, it could be cargo, it could be a military variant, it could be for firefighting or some type of scientific research. We've approached it the same way."

Those are the sorts of opportunities that SNC hopes to pursue in the future, and those are the sorts of inquiries that Sirangelo may well be getting – although he declined to provide details during this week's interview.

The bottom line is that after 10 years of development, NASA's contract announcement finally provided the critical mass to turn the Dream Chaser into a reality. "People now see that the vehicle will be built," Sirangelo said.

So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere – analogous to the tests that were done in the late 1970s using the space shuttle prototype known as the Enterprise.

For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.

At the same time, SNC is working with one of its lead industrial partners, Lockheed Martin, to build the structures for its space-capable Dream Chasers. Meanwhile, the European Space Agency has signaled that it will go ahead with a $36 million investment in Dream Chaser construction.

In 2019, SNC expects to be ready to send its first flight into orbit, taking advantage of an Atlas 5 rocket reservation it made with United Launch Alliance two years ago.

2019 really isn't all that far away, based on what it takes to get a new spaceship working. But Sirangelo is confident that SNC and its "Dream Team" of more than 60 partners can meet the schedule. "I'm fortunate to be leading what I believe is the best team in the space industry," he said.

This report has been corrected to reflect the fact that that Sierra Nevada Corporation is headquartered in Sparks, Nev.

I perused their jobs web page and they don't seem to have to many jobs available for the moment. That's not surprising given the tumultuous history they had in the last decade. But perhaps in the very near future, and now having NASA and European monetary commitment there may be jobs available for "aerodynamicists" like me when they start drop testing the mock vehicle.  I may send my resume and see if per chance they keep it and not send it to the trash bin.

[Khem Caigan]

I perused their jobs web page and they don't seem to have to many jobs available for the moment. That's not surprising given the tumultuous history they had in the last decade. But perhaps in the very near future, and now having NASA and European monetary commitment there may be jobs available for "aerodynamicists" like me when they start drop testing the mock vehicle.  I may send my resume and see if per chance they keep it and not send it to the trash bin.

[ Addenda to my Note to Sinter Klaas : Along with that
single-stage rocket, I would really appreciate an Open
Source, upgraded version of the old Dyna-Soar (still
decades ahead of its time ) parked on top. ]

[J. Wilhelm]

I'm not sure whether I'd qualify it as ahead of it'd time, but Dyna Soar was a logical and smart solution to the requirement of blunting in hypersonic vehicles to reduce heat transfer at the skin.

In hypersonics, the shape of your vehicle is intimately related to the thermal resistance properties of the materials you use. As an "aerodynamicist" my primary concern is achieving a controlled descent, approach and landing, with the landing being a notoriously difficult phase of the fight mission due to stability. The Space Shuttle also incorporates design elements from lifting bodies, but the chemically non reactive silica glass fuselage allows us to increase the size of the wing/lifting surfaces for added control.

All being equal, Dyna-Soar type designs remain very cool to look at. Having so much experience on this, I agree an open source Dyna Soar could be done.  Mind you,  it's nor like the knowledge is classified and closed to the public (with so much of it being a civilian project and tax-payer funded), and if you care to buy an airplane ticket and fly down to Austin, I can take you to the University of Texas Library system, where we can peruse original NASA / Rockwell International documentation on the Shuttle, for example.

[Khem Caigan]

Mind you,  it's nor like the knowledge is classified and closed to the public (with so much of it being a civilian project and tax-payer funded), and if you care to buy an airplane ticket and fly down to Austin, I can take you to the University of Texas Library system, where we can peruse original NASA / Rockwell International documentation on the Shuttle, for example.

Sucking down public money has never stopped a corporation at
the trough from taking out a patent, and not getting hit with a
patent infringement ( or at least getting away unscathed ) is
the whole point of the freely downloadable designs for trucks
and what-not that are available from sites such as
Open Source Ecology.

In other news, I may be moving my family back to Texas - by
way of a road trip.

Ironically, I don't fly.

Perhaps we will see you there - I'll be headed over to the Harry
Ransom center to give the papers of Charles Henry Allan
Bennett a thorough going-over.

[J. Wilhelm]

Mind you,  it's nor like the knowledge is classified and closed to the public (with so much of it being a civilian project and tax-payer funded), and if you care to buy an airplane ticket and fly down to Austin, I can take you to the University of Texas Library system, where we can peruse original NASA / Rockwell International documentation on the Shuttle, for example.

Sucking down public money has never stopped a corporation at
the trough from taking out a patent, and not getting hit with a
patent infringement ( or at least getting away unscathed ) is
the whole point of the freely downloadable designs for trucks
and what-not that are available from sites such as
Open Source Ecology.

In other news, I may be moving my family back to Texas - by
way of a road trip.

Ironically, I don't fly.

Perhaps we will see you there - I'll be headed over to the Harry
Ransom center to give the papers of Charles Henry Allan
Bennett a thorough going-over.

Keep me advised then. I no longer am in the university and I'm afraid my life is very humble at the moment, mostly limited to a 5 mile radius (as I have no car) where I live - though not too far from the university. I am trying to lift myself out of a decade long financial catastrophe after my family business collapse and grandfather's death, and I'm also currently stunned / dumbfounded by my inability to return to engineering. Perversely, some of my regular  customers at my current place of employment happen to be former professors and including one graduate supervisor. This is a time of great shame and fear for me, to be honest. But I have resolved that change must come fast, even if it means expatriation. But for the moment I'm alive, and I'd be happy to meet you and your family.