Global Flyer

"Robert Bonomi" wrote in message
...

Foreign? Uh-uh. Soon as that footpad touched down, it was U.S. soil by
historical custom.

Well, *except* for the fact that the U.S. government was already a
signatory
to an international treaty _disclaiming_ any such claims of territorial
ownership "in space".

Details, details. I got the big picture when I saw the Stars and Stripes
rippling in the Solar Wind there on the Mare. Hmm.... there's a song in that
somewhere. . .

Rich "It's up to the lawyers now" S.

"Robert Bonomi" wrote in message
...

Well, *except* for the fact that the U.S. government was already a
signatory
to an international treaty _disclaiming_ any such claims of territorial
ownership "in space".

But what I *really* wanted to explore was design ideas for a homebuilt
"airborne" Moon vehicle.

Here's the scene: You're living on Luna, having retired from ______ (fill in
blanks at your pleasure). It's the year ____ and low-gravity retirement has
become the "in" thing. You live longer, the old aches and pains are less,
etc. Your Social Security private trust fund has built up to the point that
you just *have* to start spending some of it! The one thing you miss since
moving out here is roaring around in your homebuilt on Saturday afternoons.
So, absent any regulation to the contrary, you decide to build a Lunar
replacement.

First thing to decide on is a name for the critter. Hmmm..... Moonraker
sounds appropriate. Wonder if anybody has used that one? Oh heck with that,
let's get on to the design parameters.

Seats - One, two???
Pressurization - (?) if not, then a big enough seat to accommodate a space
suit.
Range - There's fuel and air caches every 1,800 miles, so let's add ~10% and
say 2,000 miles.
Speed - Let's say 600 knots. (What I'm doing is multiplying typical terran
specs by 6. Why? I dunno)
Payload - (?) We can let the Mass/Weight guys duke that one out.
Visible means of support (Lift) - Wonder if NASA has an airfoil for an
airless environment? If not, we'll have to come up with something. I
wouldn't want to go ballistic - it's not as much fun as low & slow.
Thrust - Open for suggestions. . .
Primary source of power - Anybody got a design for something better than a
Chinese sparkler?

C'mon guys. There's got to be another Rutan out there. What are we going to
do when he's history?

Rich S.

"Rich S." wrote

But what I *really* wanted to explore was design ideas for a homebuilt
"airborne" Moon vehicle.

First, with all that extra disposable income from Social Security (Yea, who
said you couldn't dream big) you have to think terraforming first, and
create an atmosphere.

I know! Get Zoom and Yaun up there! They are both full of hot air, and we
can worry about cooling it off, later!

Let's see, if we get it up to 1/5th density, then we could fly at the same
speeds we see here on Earth, right?
--
Jim in NC

On Sat, 5 Mar 2005 07:29:57 -0800, "Rich S."
wrote:

But what I *really* wanted to explore was design ideas for a homebuilt
"airborne" Moon vehicle.

Here's the scene: You're living on Luna, having retired from ______ (fill in
blanks at your pleasure). It's the year ____ and low-gravity retirement has
become the "in" thing. You live longer, the old aches and pains are less,
etc. Your Social Security private trust fund has built up to the point that
you just *have* to start spending some of it! The one thing you miss since
moving out here is roaring around in your homebuilt on Saturday afternoons.
So, absent any regulation to the contrary, you decide to build a Lunar
replacement.

"Moon Zero Two", 1969, starring James Olson.

First thing to decide on is a name for the critter. Hmmm..... Moonraker
sounds appropriate. Wonder if anybody has used that one?

Been there, done that:

http://www.bowersflybaby.com/stories/leoraker.JPG

Oh heck with that,
let's get on to the design parameters.

Seats - One, two???

With a weight increase, the amount of fuel needed increases disproportionately.
Also, if you add a second seat, you're always going to have to have a body or
ballast in the spot to keep the beast in balance.

Pressurization - (?) if not, then a big enough seat to accommodate a space
suit.

It's tough to do precision work in a space suit. The gloves give you next to no
tactile feel...in fact, the fingertips are usually covered with hard rubber
shells.

http://www.hightechscience.org/orlan_space_glove.htm

You're not going to be able to work a keyboard, and if you have buttons and
whatnot to push, they're going to have to be well separated to ensure you don't
punch the wrong one. It's gonna be tough to fly without a pressurized cabin.

But...again, pressurization is going to add a lot of weight. You not only need
a pressure hull with windows and an openable door, but you're going to need the
typical air conditioning functions such as oxygen replacement, CO2 removal,
humidity control, etc. Since these problems are ALREADY solved with a space
suit, you might as well just go open cockpit...after all, you'll need a space
suit onboard anyway for the walk from the landing field to the cafe for that
$100,000,000 hamburger.

Hmmmm, single seat, open cockpit. The Luna Baby? :-)

Range - There's fuel and air caches every 1,800 miles, so let's add ~10% and
say 2,000 miles.

2000 miles is about 1/3 the way around the entire moon...2/3rds the maximum
distance you'd want to fly, anyway.

It's been years since I did any sort of lunar orbit work (and even that was only
for a week or so...damned if I can even remember what program it was). To get
some answers, I modified one of my orbit analysis tools to do Moon orbits
(changed the values for G, planetary radius, and gravitational constant). In
other words, lotsa approximations here.

For a 2000-mile ballistic trajectory on the Moon that gets at least 10 NM high,
you'll need about 5000 FPS of acceleration. And if you want to touch down with
near-zero speed, you'll need about the same for deceleration. We'll call it a
total of 10,000 FPS. Flight time less than a half hour, including accel and
decel.

Let's assume an open-cockpit single-seater. Call it 200 lbs for the pilot,
another 100 lbs for his suit, 500 pounds of airframe, 20 pounds of avionics, and
50 pounds for batteries and life support supplied. Let's assume our rocket fuel
has a specific impulse of 250 seconds. That's a dry weight of about 870 pounds.

The fuel comes out to another 2150 pounds.

Like Robert said, though, we could use a mass driver or other ground-based
system to throw the vehicle, and just rely on onboard fuel to land. This drops
the required onboard fuel to about 750 pounds. Not too bad.

Speed - Let's say 600 knots. (What I'm doing is multiplying typical terran
specs by 6. Why? I dunno)

Visible means of support (Lift) - Wonder if NASA has an airfoil for an
airless environment? If not, we'll have to come up with something. I
wouldn't want to go ballistic - it's not as much fun as low & slow.

Yep, ballistic wouldn't be much fun. You want a "Hollywood" moon flight: Take
off, climb to a given altitude, cruise at that altitude through the entire
flight, then descend to land.

If we don't have antigravity, what's it going to take?

Let's look at the cruise speed first. 600 knots is about 1000 FPS, and we'll
need both acceleration and deceleration fuel. Total 2000 FPS. Give it another
500 FPS to cover the climb (coming down is free!).

To fly at the constant altitude, we'll need constant downward thrust to
counteract the force of gravity. Since we're flying 2000 NM at 600 knots, we
have to do this for about 3.3 hours. Call it four hours with VFR reserves. :-)

So...we have to burn our downward thrusters for four hours. "G" on the Moon is
about 5.6 ft/Sec^2. We'd need to burn the same to counter that. Total
acceleration required is 5.6 ft/sec^2 x 4 hours x 3600 seconds/hour... about
80,000 FPS, about sixteen times more than a ballistic S/C using a mass driver
for launch, and, as a point of interest, almost three times what a spacecraft
launch from the *Earth* needs. With the accel/decel Delta-V, our 870-pound
spacecraft requires 24.9 *million* pounds of fuel.

C'mon guys. There's got to be another Rutan out there. What are we going to
do when he's history?

Live far more boring lives, I reckon....

Ron Wanttaja

Ron Wanttaja wrote:

On Sat, 5 Mar 2005 07:29:57 -0800, "Rich S."
wrote:


But what I *really* wanted to explore was design ideas for a homebuilt
"airborne" Moon vehicle.

Here's the scene: You're living on Luna, having retired from ______ (fill in
blanks at your pleasure). It's the year ____ and low-gravity retirement has
become the "in" thing. You live longer, the old aches and pains are less,
etc. Your Social Security private trust fund has built up to the point that
you just *have* to start spending some of it! The one thing you miss since
moving out here is roaring around in your homebuilt on Saturday afternoons.
So, absent any regulation to the contrary, you decide to build a Lunar
replacement.


"Moon Zero Two", 1969, starring James Olson.


First thing to decide on is a name for the critter. Hmmm..... Moonraker
sounds appropriate. Wonder if anybody has used that one?


Been there, done that:

http://www.bowersflybaby.com/stories/leoraker.JPG


Oh heck with that,
let's get on to the design parameters.

Seats - One, two???


With a weight increase, the amount of fuel needed increases disproportionately.
Also, if you add a second seat, you're always going to have to have a body or
ballast in the spot to keep the beast in balance.


Pressurization - (?) if not, then a big enough seat to accommodate a space
suit.


It's tough to do precision work in a space suit. The gloves give you next to no
tactile feel...in fact, the fingertips are usually covered with hard rubber
shells.

http://www.hightechscience.org/orlan_space_glove.htm

You're not going to be able to work a keyboard, and if you have buttons and
whatnot to push, they're going to have to be well separated to ensure you don't
punch the wrong one. It's gonna be tough to fly without a pressurized cabin.

But...again, pressurization is going to add a lot of weight. You not only need
a pressure hull with windows and an openable door, but you're going to need the
typical air conditioning functions such as oxygen replacement, CO2 removal,
humidity control, etc. Since these problems are ALREADY solved with a space
suit, you might as well just go open cockpit...after all, you'll need a space
suit onboard anyway for the walk from the landing field to the cafe for that
$100,000,000 hamburger.

Hmmmm, single seat, open cockpit. The Luna Baby? :-)


Range - There's fuel and air caches every 1,800 miles, so let's add ~10% and
say 2,000 miles.


2000 miles is about 1/3 the way around the entire moon...2/3rds the maximum
distance you'd want to fly, anyway.

It's been years since I did any sort of lunar orbit work (and even that was only
for a week or so...damned if I can even remember what program it was). To get
some answers, I modified one of my orbit analysis tools to do Moon orbits
(changed the values for G, planetary radius, and gravitational constant). In
other words, lotsa approximations here.

For a 2000-mile ballistic trajectory on the Moon that gets at least 10 NM high,
you'll need about 5000 FPS of acceleration. And if you want to touch down with
near-zero speed, you'll need about the same for deceleration. We'll call it a
total of 10,000 FPS. Flight time less than a half hour, including accel and
decel.

Let's assume an open-cockpit single-seater. Call it 200 lbs for the pilot,
another 100 lbs for his suit, 500 pounds of airframe, 20 pounds of avionics, and
50 pounds for batteries and life support supplied. Let's assume our rocket fuel
has a specific impulse of 250 seconds. That's a dry weight of about 870 pounds.

The fuel comes out to another 2150 pounds.

Like Robert said, though, we could use a mass driver or other ground-based
system to throw the vehicle, and just rely on onboard fuel to land. This drops
the required onboard fuel to about 750 pounds. Not too bad.


Speed - Let's say 600 knots. (What I'm doing is multiplying typical terran
specs by 6. Why? I dunno)

Visible means of support (Lift) - Wonder if NASA has an airfoil for an
airless environment? If not, we'll have to come up with something. I
wouldn't want to go ballistic - it's not as much fun as low & slow.


Yep, ballistic wouldn't be much fun. You want a "Hollywood" moon flight: Take
off, climb to a given altitude, cruise at that altitude through the entire
flight, then descend to land.

If we don't have antigravity, what's it going to take?

Let's look at the cruise speed first. 600 knots is about 1000 FPS, and we'll
need both acceleration and deceleration fuel. Total 2000 FPS. Give it another
500 FPS to cover the climb (coming down is free!).

To fly at the constant altitude, we'll need constant downward thrust to
counteract the force of gravity. Since we're flying 2000 NM at 600 knots, we
have to do this for about 3.3 hours. Call it four hours with VFR reserves. :-)

So...we have to burn our downward thrusters for four hours. "G" on the Moon is
about 5.6 ft/Sec^2. We'd need to burn the same to counter that. Total
acceleration required is 5.6 ft/sec^2 x 4 hours x 3600 seconds/hour... about
80,000 FPS, about sixteen times more than a ballistic S/C using a mass driver
for launch, and, as a point of interest, almost three times what a spacecraft
launch from the *Earth* needs. With the accel/decel Delta-V, our 870-pound
spacecraft requires 24.9 *million* pounds of fuel.


C'mon guys. There's got to be another Rutan out there. What are we going to
do when he's history?


Live far more boring lives, I reckon....

Ron Wanttaja

Hey, they didn't do it that way in "2001 a Space Odyssey" when they
cruised across the surface ofthe moon in the moon bus.

Dan "who thinks Ron has shot down my dreams", U.S. Air Force, retired

"Dan, U.S. Air Force, retired" wrote in message
news:rGsWd.24184$Sn6.22376@lakeread03...

Hey, they didn't do it that way in "2001 a Space Odyssey" when they
cruised across the surface ofthe moon in the moon bus.

Wasn't that a monorail or cable-suspended car?

Rich "running low on memory" S.

On Sat, 05 Mar 2005 19:11:22 GMT, Ron Wanttaja
wrote:



Let's assume an open-cockpit single-seater. Call it 200 lbs for the pilot,
another 100 lbs for his suit, 500 pounds of airframe, 20 pounds of avionics, and
50 pounds for batteries and life support supplied. Let's assume our rocket fuel
has a specific impulse of 250 seconds. That's a dry weight of about 870 pounds.


forgive my iggorance.
are we talking earth pounds, moon pounds or mass?
and if we are talking mass is it roman catholic, anglican or
engineering?
you get that for ruining dreams :-)


what is actually needed is for someone to do a Wright Brothers on
gravity.
aviation would go another quantum leap forward if we could just negate
the aircraft weight without all that drag.
it is amazing that with all our progress we havent made one single
inroad into understanding or controlling gravity.

Star Wars episode 1, The phantom menace was shown on local telly last
night. I'm amazed at how correct the understanding of an antigravity
world was in that film.
Stealth (ok, antigravity liftoff, now how do we get thrust?) Pilot

On Sun, 06 Mar 2005 14:03:42 +0800, Stealth Pilot wrote:

On Sat, 05 Mar 2005 19:11:22 GMT, Ron Wanttaja
wrote:



Let's assume an open-cockpit single-seater. Call it 200 lbs for the pilot,
another 100 lbs for his suit, 500 pounds of airframe, 20 pounds of avionics, and
50 pounds for batteries and life support supplied. Let's assume our rocket fuel
has a specific impulse of 250 seconds. That's a dry weight of about 870 pounds.

forgive my iggorance.
are we talking earth pounds, moon pounds or mass?
and if we are talking mass is it roman catholic, anglican or
engineering?

Now stop that. :-)

what is actually needed is for someone to do a Wright Brothers on
gravity.
aviation would go another quantum leap forward if we could just negate
the aircraft weight without all that drag.
it is amazing that with all our progress we havent made one single
inroad into understanding or controlling gravity.

You've hit the nail right on the head. Right now, space travel is at the
equivalent level of the Montgolfier brothers. Chemical rockets are a dead end;
the moral equivalent of de Rozier's combination hot air/hydrogen balloon.

Heavier than air flight wasn't possible until the invention of the internal
combustion engine. Similarly, the true exploitation of space is waiting for a
system that will produce good acceleration without the need of tons of fuel.

It's sort of in our grasp, now. Chemical fueled engines have Specific Impulses
(Isp) in the range of 200-300 seconds. Modern electric propulsion units see
ISPs up to about 3000 seconds.

What does that mean? Well, I used an Isp of 250 for the thrust-hovering moon
buggy. If you recall, it needed 25 million pounds of fuel for Rich's
cross-country.

With an ISP of 3000, the fuel requirement drops from 25,000,000 pounds...to a
bit over 1,000. Yes, about four orders of magnitude. These units are
operational *now*...they're used on communications satellites.

They produce a lot of thrust for very little fuel, but the actual amount of
thrust they produce is minuscule. The commsats use them to compensate for the
north-south wobble their orbits get from the uneven distribution of mass within
the earth. They need 150 FPS of delta-V per year, and they run the electric
propulsion nearly constantly.

As you might expect, they require a lot of power. But a dozen miles from Rich's
house, a number of airtight spacecraft hulls complete with operational nuclear
power plants lie in storage. The Navy calls them, "mothballed submarines."
Back when a tsunami hit Hawaii forty or so years ago, they powered Honolulu with
the output of *one* of these subs.

Cooling them in space, where you don't have access to billions of tons of cold
sea water, is left to the good offices of your local thermal engineer.

Ron Wanttaja

"Ron Wanttaja" wrote in message
...

"Moon Zero Two", 1969, starring James Olson.

Ooh - I'll look that one up!

With a weight increase, the amount of fuel needed increases
disproportionately.
Also, if you add a second seat, you're always going to have to have a body
or
ballast in the spot to keep the beast in balance.

We'll just make the ship expandable. When you've got a passenger, just
unlatch it in the middle and pull the ends out - like you do with the dining
table when Grandma's coming.

You're not going to be able to work a keyboard, and if you have buttons
and
whatnot to push, they're going to have to be well separated to ensure you
don't
punch the wrong one. It's gonna be tough to fly without a pressurized
cabin.

Who sez the spacesuit can't have a keyboard- or even a joystick? Pull your
arms inside and start typing. 'Course the chest area would look like Jayne
Mansfield's.

2000 miles is about 1/3 the way around the entire moon...2/3rds the
maximum
distance you'd want to fly, anyway.

Hmmm... I forgot about how small the circumference is. Maybe 2,000 miles is
more than we need. There's bound to be other colonies less than 2K miles
apart.

Like Robert said, though, we could use a mass driver or other ground-based
system to throw the vehicle, and just rely on onboard fuel to land. This
drops
the required onboard fuel to about 750 pounds. Not too bad.

Naw - can't go for the ground based system. What if you want to stop for a
picnic on the shore of the Mare?

Yep, ballistic wouldn't be much fun. You want a "Hollywood" moon flight:
Take
off, climb to a given altitude, cruise at that altitude through the entire
flight, then descend to land.

If we don't have antigravity, what's it going to take?

Well, maybe we *do* have antigravity. After looking at your figures (not
that I understand them), did you say that 5,000 fps is orbital velocity at
10 NM MSL? If so, then what speed is orbital velocity at 1,000' MSL (Moon
Surface Level)? Cruising at that speed would obviate the need for constant
vertical thrust. Half that speed would require less constant vertical thrust
than a hover. If you could find a happy medium, perhaps a small fuel cell,
plutonium reactor, cold fusion motor, or bag of rocks and Hernadez's 98 mph
fast ball would do it.

C'mon guys. There's got to be another Rutan out there. What are we going
to
do when he's history?

Live far more boring lives, I reckon....

"May you live in interesting times"

Rich "Call Hazel Stone" S.

On Sat, 5 Mar 2005 23:50:23 -0800, "Rich S."
wrote:

"Ron Wanttaja" wrote in message
.. .

"Moon Zero Two", 1969, starring James Olson.

Ooh - I'll look that one up!

It's known as the first space western.... :-)

With a weight increase, the amount of fuel needed increases
disproportionately.
Also, if you add a second seat, you're always going to have to have a body
or
ballast in the spot to keep the beast in balance.

We'll just make the ship expandable. When you've got a passenger, just
unlatch it in the middle and pull the ends out - like you do with the dining
table when Grandma's coming.

You might be able to do something along those lines...depending on how much
acceleration you plan on. Airplanes can tolerate CG shifts because they have
horizontal stabilizers at the end of a longish moment arm. Spacecraft don't.
However, with a fly by wire control system, you could compensate for weight
offsets so the vehicle flies about the same.

You could also handle the problem with something Heinlein referred to as "A
Space Suit Built for Two."

You're not going to be able to work a keyboard, and if you have buttons
and whatnot to push, they're going to have to be well separated to ensure you
don't punch the wrong one. It's gonna be tough to fly without a pressurized
cabin.

Who sez the spacesuit can't have a keyboard- or even a joystick? Pull your
arms inside and start typing. 'Course the chest area would look like Jayne
Mansfield's.

Or just make the suit something like the Jim suits used for diving...

http://www.divingheritage.com/jimkern.htm

Assuming you're not fixed on a Buck Rogers style ship (or even a Space 1999
style ship...) you could make your buggy from a hard-shell space suit. You
probably won't look like Jayne, more like Robbie the Robot ("Danger, Rich
Shankland!").

Like Robert said, though, we could use a mass driver or other ground-based
system to throw the vehicle, and just rely on onboard fuel to land. This
drops
the required onboard fuel to about 750 pounds. Not too bad.

Naw - can't go for the ground based system. What if you want to stop for a
picnic on the shore of the Mare?

Ohhhh, now you want *floats*.... :-)

Well, maybe we *do* have antigravity. After looking at your figures (not
that I understand them), did you say that 5,000 fps is orbital velocity at
10 NM MSL? If so, then what speed is orbital velocity at 1,000' MSL (Moon
Surface Level)? Cruising at that speed would obviate the need for constant
vertical thrust. Half that speed would require less constant vertical thrust
than a hover. If you could find a happy medium, perhaps a small fuel cell,
plutonium reactor, cold fusion motor, or bag of rocks and Hernadez's 98 mph
fast ball would do it.

The problem is, the required orbital velocity is based on the spacecraft's
distance *from the center of the orbital body*, not its distance above the
surface. So the difference is just 30 FPS between orbits 10 NM high and 1000
feet high.

And, in fact, the orbital velocity decreases with increased altitude...but, of
course, you have to burn fuel to get to the altitude.

The 5000 FPS was for a ballistic case, not an orbit. I brute-forced this one to
determine the velocity needed...I used an orbit with a 10 nm apogee and pushed
the perigee below the surface until I had an orbit where the above-ground
portion was approximately 2,000 NM long (it really, REALLY helps to write your
own orbit analysis programs).

Ron Wanttaja