Re: Bigelow's BA300 as a Martian spaceship?

On May 15, 2:36 pm, "Jorge R. Frank" <jrfr...@xxxxxxxxxxx> wrote:
Jim Relsh wrote:

I would also opt for a 'Russian style mission' (the Soviets studied a manned
Martain landing for decades) which is to go there, stay for a week, and then
return. Not the U.S. style 'stay on the surface for nearly a year' type of
mission, which, IMHO, is fraught with danger.

Long surface stays are dictated by orbital mechanics. You do not get a
minimum-energy return opportunity for at least ninety days after
arrival. You can leave after a week if you really want to, but it will
cost more propellant *and* keep you in space longer. That, in my
not-so-humble opinion, is fraught with more danger than a long surface
stay and is not a good trade.

http://www.astronautix.com/craft/nautilus.htm
http://en.wikipedia.org/wiki/Bigelow_Aerospace

They seem to be thinking Atlas V launcher for their BA 330 space
station.

Length: 13.70 m (44.90 ft).
Basic Diameter: 4.57 m (14.99 ft).
Maximum Diameter: 6.70 m (21.90 ft).
Habitable Volume: 330.00 m3.
Mass: 20,000 kg (44,000 lb).
Electrical System: Solar cells.

Alright. this is suited for the Atlas V Growth Phase 3

http://www.astronautix.com/lvs/atlhase3.htm

Manufacturer: Convair.
Payload: 44,000 kg (97,000 lb). to a: earth escape trajectory.
Liftoff Thrust: 35,300.000 kN (7,935,700 lbf).
Total Mass: 2,900,000 kg (6,300,000 lb).
Core Diameter: 5.00 m (16.40 ft).
Total Length: 63.00 m (206.00 ft).
Span: 15.00 m (49.00 ft).

The upper stage is a restartable LOX/LH stage.-

This would permit boosting the BA 330 - Nautlius - Transhab - whatever
you wanna call it - to a lunar free return trajectory and having it
return to Earth. The module is unlikely to withstand re-entry, but if
it could! - wow.

You'd have $200 million - per trip - and with 7 people paying $100
million each - you'd have a good business plan there.

A Mars Free Return Trajectory entails boosting with enough speed to
reach an apoheion 335 million kilometers from the sun, and timing
launch to fly by Mars.and come back to Earth without any further
rocket inputs - in exactly 2 years.

Would 3 people pay $500 million each to go down in the history books?

Part of the mission would be to aerobrake ASIMO type robots down to
the surface of mars - with a telepresence suite - so for 2 days - the
3 people would have near real time interaction on the surface. Like
the lunikod's they could return samples chosen by the explorers - to
take home and put in their offices or studies and donate to the
Smithsonian when they died..

This would be followed on by a landing on the moon - and later - a
landing on Mars.
The delta-vees are pretty much the same.

http://www.astronautix.com/craft/morflyby.htm
..
A reusable transhab/nautllus/ba 330 module,that deflated and executed
a powered touchdown - on Earth - would be the first step toward doing
a Mars or lunar lander.

To get the legs to do those missions requires TWO - launches in
parallel and the development of some sort of booster/lander
hardware.

A 20 metric ton station - is the payload - and to land on the moon
from a free return trajectory - and return to Earth - this is the
original Direct Ascent approach - its far simpler and takes less
vehicle types and so forth - and is immediately translatable to a Mars
expedition - if you have MEMs based highly efficient life support
systems.

http://home.tiac.net/~cri/1999/moon.html

To land from a free return trajectory to Earth and escape back to
Earth requires 2.3 km/sec each time. A total delta vee of 4.6 km/
sec. Using a high expansion lox/lh engine robtains 4.6 km/sec in
vacuum. An RL10 perhaps with a high expansion nozzle. This implies a
mass fraction of;

u = 1 - 1/e = 0.6321

63.2%

So, if the Atlas V is limited to 20 tons to a lunar free return
trajectory - we'vfe got to reduce the transhab/nautilus/ba 330 by half
- which is what Bigelow is doing!

So,you don't do TWO - you do ONE-HALF - see?

Actually, Lofting 40 tons in two parts - and taking 64% of the total -
means 20 tons on the unpiloted portion - and 5.6 tons propellant on
the piloted portion and 14.4 tons for the payload.

So, the way this would work would be...

Launch an Atlas V - with the unmanned portion - the booster into an
escape trajectory at the same time you launch aanother Atlas V - with
a manned portion.on the same trajectory. Dock in transit to the
moon. Brake to a soft touchdown - dropping from 2.3 km/sec to 0.0 km/
sec at zero altitude. Do your moon stuff. When you're done,launch
back directly to Earth by adding 2.3 km/sec - enter the atmosphere,
aerobrake, and land. Since this is a commercial venture, I would
like to see them - as an investor - reuse all the hardware they make.
Get at least 10 flights out of it. That way you only pay for two
Atlas Vs.

This would be done after the orbital transhab, then the lunar
flybyb,then the mars flyby. That by itself could do a lot.

Adding a booster that you dock with - to land on the moon with a cut
down version of the transhap - 14 tons instead of 20 - and return to
Earth - would be cool.

The same setup would get you to Mars.

Fire the two systems onto a trajectory to Mars. Dock the two systems
in transit. Use a bolo for artificial gravity (this might be tried
out on the moon trips too) This involves docking with a module that
has a tether coiled up inside - and then unrolling the tether - and
spinning the two parts to produce artificial gravity in transit. this
was done with an agena stage during one of the gemini missions

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

The cool thing is, Gemini proved all that you need to do all this
stuff in space. You can launch two boosters within 90 minutes of
each other, get them to rendezvous with their payloads, one unmanned,
dock them, tether them, spin them up,etc.,etc., etc. This in the
1960s dude! We can do as well today. Better.

All it takes is the will to do it.

Okay, so, the BA 330 equipped with aerobraking for recovery at Earth,
and a rocket pack to bring it to zero speed at zero altitude - is the
first step. Lunar free return - and recovery. The second step.
Mars free return (2 year orbit ) and recovery third step. Booster to
add propellant to the system in transit, to land on the moon through
direct ascent, and return to Earth by direct flight back (no moon
orbit)

Finally..

Mars landing

You launch into a 2 year orbit - just in case something screws up in
transit - you get back to Earth - no problem.

But this time, when you fly by mars... you do more than just send a
couple of modified Asimo robots down with a sample return rocket...

you redirect to aerobrake a fully loaded module with propellant
tanks...

then, when the planets align for a minimum energy return... you take
off directly from mars with your propoellants.. (you used very little
propellant getting down,relying instead on aerobraking)

So,during landing you use 0.1 km/sec - to get back to Earth you need...
5.0 km/sec - which is a little more than 4.6 km/sec... and another
1.1 km per sec to transfer from Mars orbit around the sun to Earth
orbit at perihelion. That's 6.1 km/sec.

Using the same 4.6 km/sec engine exhaust velocity - you've got to have

u = 1 - 1/exp(6.1/4.6) = 0.7345

Which means that for every ton of payload you need 2.767 tons of
propellant. Now our slimmed down transhab we built to land on the
moon - masses 14.4 tons - which means 40 tons of propellant are
needed. THATS NICE!

So, our Mars ship looks like this;

1 slimmed down transhab
2 propellant tanks - docked to the transhab

And you've got 5.6 tons of propellant on board the transhab - or
rather you can divide that 27% 73% - and carry a ffew extra tons of
supplies.

So, you need three launches in quick succession - attach a portion of
one of the propellant sets in the landing configuration - attach the
remaining propellant to the bolo - and spin up. You did this trick
already to have balanced bolo operation on your earlier missions.
Before separating - transfer propellant to the landing configuration -
and aerobrake to a llanding on Mars -with twice the propellant you had
for the lunar landing. You arrive nearly full - and stay that way
while you wait to return to Earth. You reconfigure your solar panels
for ground operation on Mars while you wait. Then, you put your
panels back together - and blast off- back for Earth - along a
minimumenergy trajectory. Land on Earth - keep all the pieces and
parts - and do it again.

Slimmed down version - long duration times - 3 to 4 paying passengers
and 2 to 3 crew - $500 million each - to make it worthwhile. And two
years of your life! - but what a trip!

I would say the first Mars landing - with 4 paying customers - would
mean that you have to pass a test, and you've gotta earn your keep in
transit - no lace hankies or anything like that - a bottle fo
champagne on mars definitely and another on return to Earth - but a
lot of hard work- before and during the trip. I'd say you could
charge $2 billion per person - that gets you $8 billion for four - and
there are folks that have it out there! You might even get a
government or two to pay the tab.

You could develop a 14.4 ton transhab type module, with long duration
life support, and two 20 ton propellant modules that can be configured
for landing and return. And do the Mars trip first - followed by
lower cost moon trips aboard the same historic vehicle.

THAT would be a marketing plan.

in fact offer the guys or gals who put up $2 billion each - to
nominate others if they don't want to go, and give them a share of the
revenues to be earned from monthly flights to the moon aboard the same
ship.

Safety is an issue for anyone. 2 years another issue. $2 billion a
third issue - though there are 700 people who could afford it!

But, spending 3 weeks to get ready and 1 week to fly to the moon - for
$100 million - 8,000 people can afford that -

So, this is the way to go.

Go to mars first, in a reusable payload - and cycle the payload to the
moon about 50 times over a 4 year period following - with twice the
number of passengers per flight.

7 pax x $100 million = $700 million per flight
$700 million x 12 = $8.4 billion per ;year
$8.4 bililon x 4 = 33.6 billion

So,give the original 4 mars explorers - $4 billion each of this
revenue for spending $2 billion today PLUS THE TRIP and they can
nominate another party to go in their stead..

This would appeal to anyone who made enough money to afford $2 billion
ticket anyway. And it gets them in the history books.

And it gets Bigelow more money than NASA.

Maybe he could take an Atlas V and make it a flyback booster with the
profits,and expand on this success.




.

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