Global Flyer

In article ,
Ron Wanttaja wrote:

[snip]
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.

Doesn't the vehicle get lighter as fuel and oxidizer are consumed,
requiring less thrust, lowering the consumption rate...

Dan "and-so-on, and-so-on, and-so-on" Nafe
danATscuba-trainingDOTnet

On Sun, 06 Mar 2005 23:33:48 -0500, Dan Nafe wrote:

In article ,
Ron Wanttaja wrote:

[snip]
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.

Doesn't the vehicle get lighter as fuel and oxidizer are consumed,
requiring less thrust, lowering the consumption rate...

Exactly, but the basic rocket equation takes that into account:

Fuel = Initial Mass * (1 - 1/(e^(Delta-V/(ISP * g)))

Ron Wanttaja

"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 in message ...

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

Rich S.





Big bouncy spring thing hopping between the craters...

"Blueskies" wrote in message
. com...

Big bouncy spring thing hopping between the craters...

At first I laughed - but now that Ron has 'splained things to me, you might
have been right after all!

Rich "If you have to have something to push against, why not the Moon?" S.

In article ,
Rich S. wrote:
"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???

Absolute requirement: one-plus.

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

Pressurization introduces *lots* of complications -- seals, O2 mixture supply,
etc. Not to mention what it does to weight and balance.

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

Optimist! "Origin to primary, divert to secondary, plus 'holding' time"
plus (at least) 10% of _that_ total. If you want to survive the 1st emergency,
that is. I get a requirement of about 4300mi (minimum)

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

Something to do with the underlying gravity of the situation?

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.

They do (see "solar sail", but it's not practical to deploy on Luna, due to
the high gravity there.

Thrust - Open for suggestions. . .

"We can always throw rocks."

"Ballistic" glider lets you leave the engine on the ground, at the take-off
site.

Primary source of power - Anybody got a design for something better than a
Chinese sparkler?

There's always NASA's "Orion" design.

Scaling might pose some *serious* difficulties, however.

"Robert Bonomi" wrote in message
...
In article ,

Pressurization introduces *lots* of complications -- seals, O2 mixture
supply,
etc. Not to mention what it does to weight and balance.

We'll let the spacesuit designers worry about that one, then.
"Give me one Moonsuit, Mark IV and a forty watt phased plasma rifle, please"

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

Optimist! "Origin to primary, divert to secondary, plus 'holding' time"
plus (at least) 10% of _that_ total. If you want to survive the 1st
emergency,
that is. I get a requirement of about 4300mi (minimum)

Uh-uh. No weather diversions necessary. Note: Sport Pilots may not fly at
night.

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

Something to do with the underlying gravity of the situation?

Snicker

"Ballistic" glider lets you leave the engine on the ground, at the
take-off
site.

"Glider"????

Primary source of power - Anybody got a design for something better than a
Chinese sparkler?

There's always NASA's "Orion" design.

Scaling might pose some *serious* difficulties, however.

My Citizen watch has a "Forever" battery and only needs an occasional burst
of sunlight - can we scale that up?

Rich S.

In article ,
Rich S. wrote:
"Robert Bonomi" wrote in message
...
In article ,

Pressurization introduces *lots* of complications -- seals, O2 mixture
supply,
etc. Not to mention what it does to weight and balance.

We'll let the spacesuit designers worry about that one, then.
"Give me one Moonsuit, Mark IV and a forty watt phased plasma rifle, please"

Woops! You'll have to settle for the EnergyStar compliant 34 watt one.

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

Optimist! "Origin to primary, divert to secondary, plus 'holding' time"
plus (at least) 10% of _that_ total. If you want to survive the 1st
emergency,
that is. I get a requirement of about 4300mi (minimum)

Uh-uh. No weather diversions necessary. Note: Sport Pilots may not fly at
night.

Moon-quake, Solar flare, "Deck is fouled", I can think of a bunch of reasons
that 'divert to alternate' might be required.

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

Something to do with the underlying gravity of the situation?

Snicker

No, no. That's a *Mars* bar. This is Luna. And it should be *obvious*
that "Almond Joy" is the appropriate one -- "Sometimes you feel like a nut"
*DEFINITELY* describes this 'food for thought'.

(Don't blame me if you don't like the answer. It was _your_ question, after
all.


"Ballistic" glider lets you leave the engine on the ground, at the
take-off
site.

"Glider"????

You don't really think a *PARACHUTE* will work, do you ? grin

But, yeah, "glider" -- for lack of a better term. At the landing site,
a *BIG* ramp -- with the _upper_ part conforming to the ballistic trajectory
you launched into. You have on-board 'maneuvering' thrusters, to tweak
you path to the _exact_ ramp trajectory -- a GCA "glide slope" with a
*vengeance*. You touch down on the ramp, and roll out, possible friction
brakes, possible aircraft-carrier type snubbing cable.

(I just realized that this is a _ground-based_ 'ballistic recovery system'!


Of course, this system makes "divert to alternate" a physical impossibility.
Unless you carry a *ridiculous* amount of 'delta v' on board.

Primary source of power - Anybody got a design for something better than a
Chinese sparkler?

There's always NASA's "Orion" design.

Scaling might pose some *serious* difficulties, however.

My Citizen watch has a "Forever" battery and only needs an occasional burst
of sunlight - can we scale that up?

You can *try*, but I suggest that -first- you calculate the energy-density
of that system. then contemplate the mass requirements, _just_ to power
your "forty watt plasma rifle" -- let alone any on-board flight controls,
instrumentation, life-support system, etc.

Rich S. wrote:
"Robert Bonomi" wrote in message
Optimist! "Origin to primary, divert to secondary, plus 'holding' time"
plus (at least) 10% of _that_ total. If you want to survive the 1st
emergency,
that is. I get a requirement of about 4300mi (minimum)


Uh-uh. No weather diversions necessary. Note: Sport Pilots may not fly at
night.

Wait a minute there, the lunar days are about 28 times as long as
ours. Spending all that time on the dark side of the moon may make
currency requirements difficult- say you don't log enough takeoffs or
landings for an entire lunar day, plus the prior and following lunar
nights, do the math, it's a long time and that's gonna be tough!

("RST Engineering")
Nor will he have to go through customs, unlike the Apollo moonwalkers, who
LANDED in a "foreign" country.


Leave only footprints, take only pictures.

"I'm sorry sir, you must leave the rocks behind - if everyone who visits our
moon takes home just one moon rock....."

Back here on Earth
We'll get you processed through customs in no time, now if you'll just step
into this Airstream trailer.

http://www.hq.nasa.gov/office/pao/Hi...otos/40147.jpg

http://www.historyplace.com/unitedst...11/isomove.jpg

We'll be back in about 20 days to let you out.


Montblack