Manned Mars Mission

On Tuesday, November 12, 2013 6:16:45 AM UTC+13, Brad Guth wrote:
On Wednesday, October 16, 2013 8:19:45 PM UTC-7, William Mook wrote:

New Technologies make rockets easier to build;







http://www.gizmag.com/3d-printed-roc...29306/pictures







India has plans for a Mars orbiter;







http://www.space.com/23204-india-mar...r-mission.html







Their lunar orbiter was about 200x more capable than America's original lunar orbiter 50 years ago, and cost about 8% the cost of America's Lunar Orbiter program.







http://www.youtube.com/watch?v=Gs-04UvCcfQ







The Mars program is coming along at about that level - far more capable than stuff America put up 50 years ago, and costing 10% or less what America paid. Of course India has America's path finding to thank along with advanced technologies, like 3D printing, MEMS and advanced electronics.







So what can we expect near term for Mars?







Well, we know far more water exists on the moon than previously thought, thanks to the hard work of Japan and India and NASA's lunar prospector in early 2000s!







http://www.youtube.com/watch?v=Y0p3HKv0wNU







http://www.youtube.com/watch?v=KIr0haov6LQ







http://www.youtube.com/watch?v=yaa2-gSdwsw











Now, using solar power satellites at L1 and L2 we can decompose water into hydrogen and oxygen, and use the two gases as rocket propellant.







Delta Vee map tells all;







Earth Surface to Low Earth Orbit: 9.20 km/sec



Low Earth Orbit to Lunar Transfer: 2.95 km/sec



Lunar Transfer to Lunar Orbit: 0.70 km/sec



Lunar Surface to Lunar Orbit: 1.70 km/sec







Low Earth Orbit to Mars Transfer: 4.15 km/sec



Lunar Orbit to Mars Transfer: 3.38 km/sec











So, for a payload to go from Low Earth orbit to Lunar orbit requires 3.65 km/sec delta vee. Then, to go from Lunar Orbit to Mars Transfer requires an additional 3.38 km/sec delta vee, after refuelling on Lunar orbit using fuel made on the Lunar surface and transferred up using a Lunar orbiting tug.







The same payload to go from Low Earth orbit directly to Mars transfer requires a 4.15 km/sec delta vee.







Using hydrogen and oxygen with an exhaust speed of 4.4 km/sec in vacuum, we can calculate propellant fractions.







From LEO to Lunar Orbit



u1 = 1-1/exp(3.65/4.40) = 0.56375







From Lunar Orbit to Mars Transfer



u2 = 1-1/exp(3.38/4.40) = 0.53614







From LEO directly to Mars Transfer



u3 = 1-1/exp(4.15/4.40) = 0.61061







So, with a 100,000 kg payload we require 56,375 kg of propellant in the first instance, 53,614 kg of propellant in the second instance, and 61,061 kg of propellant in the third instance. With an 8,000 kg structure fraction this leaves 35,624 kg in the first case, 38,385 kg in the second case and 30,938 kg in the third case.







So, a system that launched 100 tonnes into LEO would be able to send 35,624 kg to lunar orbit. On lunar orbit it would be refuelled with 56,375 kg of propellant and an additional 5,149 kg of consumables (food water and air) for the journey. It would depart to Mars carrying a total of 40,774 kg of payload.







In contrast 56,375 kg of propellant in an 8,000 kg ship can boost 27,950 kg of payload directly from LEO to Mars Transfer. Over 12 tonnes more, by stopping at the moon for a few days.







The lunar orbiter requires;







u4 = 1 - 1/exp(1.7/4.4) = 0.32048







Which given the payload of 56,375 kg of propellant and 5,149 kg of consumables made on the moon, (food, water, oxygen) require a take off weight of 109,942 kg with a propellant weight of 32,888 kg and an inert ship weight of 8,209 kg and the 4,702 kg of propellant needed to bring the ship back to the lunar surface.







If you're settling the moon anyway, as you settle mars, and you're constrained to chemical propellants made from water, then it makes sense to send mars colonists to lunar orbit, refuel there, and go on your way.







If you're using nuclear thermal rockets, exhaust speeds are about double from lox liquid hydrogen - and gains less - though still measurable. In this case you use liquid hydrogen throughout.







If you're using laser thermal rockets - exhaust speeds are about triple from lox liquid hydrogen - and gains even less. Again, you use liquid hydrogen throughout.







If you're using laser detonation rockets, or photonic rockets, payloads scale more with power, and the differences in capability vanish with mission cycle.







Of course once you arrive at Mars, you use aerobraking to slow into Mars orbit, or land on Mars' surface.











Mars Escape Velocity: 5.00 km/sec



Mars Orbit Velocity: 3.54 km/sec







Mars Transfer to Mars Orbit: 2.10 km/sec



Mars Transfer to Mars Surface: 5.64 km/sec











Here again, a vehicle that carries propellant from Mars' surface to Mars orbit can make use of the same trick as in Lunar Orbit. The crew and supplies bound for Mars can be returned since the Mars shuttle uses aerobraking to land on Mars' surface.







The same 8,000 kg vehicle that has 56,375 kg of propellant could launch







u5 = 1 - 1/exp(5.64/4.40) = 0.74227







TOW= 56,375/0.74227 = 78,031 kg



payload = 78,031 - 56,375 - 8,000 = 13,656 kg







back to Earth directly from the Martian surface.







This vehicle when operating from Martian orbit could launch







u6 = 1 - 1/exp(2.10/4.40) = 0.37953







TOW = 56,375 / 0.37953 = 148,540 kg



payload = 148,540 - 56,375 - 8,000 = 84,165 kg







A lot lot more. In fact more than double the 40,774 kg you could leave Earth with!







Of course we need to land a Mars freighter on Mars and refuel it. Its payload is 56,375 kg + 84,165 kg = 140,540 kg. To get to Mars orbit from Mars surface requires;







u7 = 1 - 1/exp(3.54/4.40) = 0.55271







TOW = 104,540 / (1-.55271-.08000) = 284,625 kg.







This could be the original 40,774 kg plus another 45,421 kg of Mars products that are sold on Earth. Or, Propellants that are used after aerobraking around Earth to start another flight cycle, reducing fresh propellant to 10,954 kg.







This reduces the 100,000 kg starting mass to 54,579 kg - assuming another 8,000 kg vessel is needed.







Propellant could also be sent from the Moon's surface via lunar freighter, to Earth orbit, more easily than from Earth's surface to Earth orbit.







Earth Surface to Lunar Orbit:



9.2 + 2.95 + 0.70 = 12.85







Lunar Surface to Lunar Surface via Earth Orbit



2.40 + 2.95 + 2.40 = 7.75







If the Lunar Freighter meets a Mars Vehicle on Earth Orbit to transfer propellant, the Lunar Freighter returns to the Moon nearly empty. So, the delta vee is closer to 5.35 km/sec instead of 7.75 km/sec. And 0.61061 fraction is needed for propellant.







So, if the 100,000 kg lift capacity to Earth orbit were a Mars mission module that made orbit devoid of propellant or consumables, we would have;







TOW = 100,000 kg / (1-0.61061) = 256,812 kg



propellant weight = 156,812



structure weight = 20,000 kg



Useful payload = 80,000 kg







If we did the same trick as we did above, we'd have a payload of 116,119 kg of useful payload leaving lunar orbit after refuelling AGAIN there.







So, a direct flight of about 25 tonnes could become an indirect flight of 116 tonnes with careful attention paid to refuelling on the Moon and Mars.







If water ice if found on Diemos or Phobos, things change again! Things become very interesting.







Now, the payload of a DC-3 is about 3,000 kg. A DC-3 carries 28 persons. A careful analysis shows that outfitted with a long duration space suit and an independent life support system, and consumables, a person can remain in space for 12 days with about 160 kg of payload - which includes their body weight which averages 85 kg per person. So, 3,000 kg could carry 18 persons for 12 days. 25,000 kg carries 156 persons. 116,000 kg carries 725 persons.





These persons would have to be in suspended animation in order to survive the 90 to 270 day transfer to Mars. 12 days animated in the vehicle would be provided for. 6 days around Earth. 6 days around Mars.





A 100 tonne payload could support the transfer of 500 to 725 persons from Earth to Mars.



The Earth-moon L1 offers a zero delta vee outpost/Gateway/OASIS to anywhere.



A cool Venus L2 or even Earth L2 are yet other zero delta vee options for going anywhere with a full load of fuels and provisions.



The use of such zero gravity-wells as efficient outposts/gateways and refueling OASIS, seems only too obvious.

I was at this concert with the love of my life - back in the day. We stayed at the Waldorf Astoria hotel ... sigh

http://www.youtube.com/watch?v=Sl_nyCBXLWc

I love you babe.

On Thursday, September 26, 2013 8:43:17 AM UTC+12, bob haller wrote:
fred



robert clark posted..... the costs to build moon fuel depots will cost far more than a nuke booster



Manned mission to Mars an unlikely proposition.

Current limits on exposure to radiation make chances of flight in near

future pretty slim.

Sep. 22, 2013

Written by Todd Halvorson FLORIDA TODAY

It's "the elephant in the room," NASA Chief Astronaut Robert Behnken

recently told a National Academy of Sciences committee.

"We're talking about a lot of ionizing radiation, almost a guarantee for

cancer, and you are really close to the edge of the range for lethal

exposure," said Kristin Shrader-Frechette, a University of Notre Dame

professor and a specialist in ethical issues that arise in scientific

research and technology development. "If we can't get shorter transit times

in space, and we can't get better shielding, then we really can't do (a

Mars) spaceflight."

http://www.floridatoday.com/article/...ly-proposition



A near term solution is already apparent: lunar derived propellant depots.

As in all things it depends on the details. However, a lunar based fuel depot will need a source of energy. That source of energy could also be nuclear.

If the nuclear power industry got behind nuclear rocket, they could make it their poster child.

On Thursday, November 14, 2013 12:27:19 AM UTC-8, William Mook wrote:
On Thursday, September 26, 2013 8:43:17 AM UTC+12, bob haller wrote:


A near term solution is already apparent: lunar derived propellant depots.


As in all things it depends on the details. However, a lunar based fuel depot will need a source of energy. That source of energy could also be nuclear.


If the nuclear power industry got behind nuclear rocket, they could make it their poster child.

With a nearly constant 1.4 kw/m2 of raw solar influx plus the 1.2 kw/m2 of surface IR that's coming back off the moon should make it kinda hard to not have sufficient energy. With some easily deployed reflectors, the concentration of solar energy at the Earth-moon L1 could be focused and thus boosted to 1.5 MW/m2. A small receiving area of 1024 m2 could easily obtain an influx of 1.536 GW.

http://us5.campaign-archive1.com/?u=...e=40afc d8f75