Mars Direct Rethought - Fixing the potholes in Zubrin's plan

Phobos · 2002-09-04 22:11:26

Another point of Mars Direct I disagree with is manned missions to different locations, and only focusing on a single location after several missions. Unmanned probes (MGS, Pathfinder, Odyssey, Mars Exploration Rover, etc.) can do the scouting for us. An unmanned sample-return is the only addition needed to select a location for a permanent base. But the base must start small. Clustering habitats together is a simiple way to start a permanent base with an affordable initial manned mission.

I also think it would be better if we just starting clustering the habs together from the beginning. Maybe we could set up two Mars bases on the planet and give the inhabitants long range rovers so they could just drive over a significant portion of the planet. Maybe we could build a "rover train" like that which the Russians envisioned in the 1960's that could carry and support a small crew driving from pole to pole. This same rover could shuttle people back and forth between the two base camps and help to break up some of the monotony.

Phobos · 2002-09-04 22:13:06

Place Holder page.

C.COMMARMOND (FR) · 2002-09-05 12:23:53

Hi, John_Frazer, I come back on your posts. You speak about 3.5 years in 0 or 0.38G. I'd like to reply that you spend 8 hours per day at 0G when you sleep, long term hospitalized people are also at 0G. in France there was a study about low G simulation, it consisted to keep people horizontal (in fact head a bit under feet) for 3 months. This said, we could do the reverse on Mars: let people sleep not horizontally but with head higher than feet to make their heart work longer. I agree that will not fully compensate for lower Gs, but it's better than nothing. Next point, when this people work outside the hab, they will carry 50Kg (heavy wears and air recycling for hours, radio, water and food, batteries...) equipment, big enough so they make some sport.

Info now for RobertDyck, Phobos and others, RKK Energia (the company) had a project included in Energia (the rocket) design: Energia-M which is supposed to put 120(/150?) metric tons on circular orbit at 200Km. This special design seems 'simple' so, for me, it should be faster to validate than the shuttle C (because the design of the main tank of Energia is 'solid' and can carry more than the 'light' design of shuttle's).

For the end, I am now thinking on a kind of thruster using thermal solar power (instead of electric solar) to make energy on the Mars space vehicle and at the same time, give thrust. We could obtain an Isp of (from basic calculations) 1200 instead of 950 for NTR with less risk and less weight (5 tons I hope + fuel).
The concept is: concentrate the sun on a heater to obtain a 2500?C gaz, use part of it to run a turbin to gain electric power, to ionize the rest of the gaz, then guide and heat this ionized gaz in a pipe where sun light is concentrated (like a kind of 30 MW 'laser'), so we don't need a material to resist the 4000?C I hope we could obtain. Fluid could be H2O, if 2500?C can break it (with a catalyst) in O2 and H2, and obtain more gaz than with H2O.

If this could work, we need less than 100 ton of fuel for 100 tons on Mars orbit (instead of approx 250 for 100 with LOX/LH).

This is for now 'utopic' since I can't test this, but the idea is now 'on the air' so I hope someone can make some calculation on it (for example, we need a 200*200 mirror to obtain 50 MW thermal) and the goal it to get some 10 MW electric and 40 MW thermal concentrated in a small pipe to heat the ionised pipe.

If someone is interrested to speak about this, tell me.

CC

RobertDyck · 2002-09-05 13:00:34

The letter I sent to RSC Energia (RKK Energia) also asked about Energia-M. That launch vehicle lost the contract to Angara. Energia-M is no longer available; if you want a launch vehicle of that size look to Angara.

I do favour the launch vehicle Energia (LV Energia) over Shuttle-C or Magnum for the simple reason it already exists, therefor no development cost.

C.COMMARMOND (FR) · 2002-09-05 14:10:39

Robert, do you know anything about big Angara, since my info are that only the smaller versions are available for now!!!

I know that Energia M lost the contract, but the design was done and 'on paper' tested. Using 'standard' componants, it seems good enough for me to pay the development.

In fact, I don't know if we need 50% more than standard LV Energia since I don't the weight of the needed payloads.

CC

RobertDyck · 2002-09-05 14:43:17

International Launch Services resells Russian launch services. They list Angara here. The Angara 5 configurations appear different than in Astronautix. But lift capacity for Angara 5A is listed as 28.5t to 200km, and for Energia-M as 38t to 200km. Astronautix lists them both part of the Energia family.

You are probably thinking of the Vulkan. That could lift 170t to 200km, but was never developed beyond an engineering study.

RobS · 2002-09-06 23:57:01

I have been thinking more about the problem of the lack of a suitable launch vehicle for human expeditions to Mars. As Robert has noted, developing a booster able to put 50-100 tonnes into low earth orbit is expensive, especially since manned flights to the moon and Mars are the only need for such a vehicle. Is it possible to use existing boosters?

ONE SCENARIO

I think it is. Here is an example of how it would work. I am assuming here a 24 tonnes to LEO (low earth orbit) capability. The space shuttle can put that much in a low orbit of moderate inclination (though NOT to the International Space Station; it?s inclination to the equator is too high). The Proton can put 21 tonnes into a high inclination orbit, so if it were launched from Kourou or Christmas Island it should be able to lift 24 tonnes into a low inclination orbit. The Atlas V and new Delta IV and the big Ariane can put about 18-21 tonnes into similar orbits. Proton may be best, as it costs $85 million per launch; for 24 tonnes, that?s only $3,300 per kilogram. But I don?t know what its availability is.

Michael Duke et al proposed (details are at ?Romance to Reality?) launching 24 tonnes into LEO divided into an 8-tonne solar-electric booster, an 8-tonne ?lunar based vehicle,? and an 8-tonne regolith processing unit. The solar-electric booster would push the other two to the Lagrange point beyond the moon, where the lunar-based vehicle would carry the regolith processing unit to Aitken or possibly to the lunar north pole.

They also note that the model they propose is about one fourth the size necessary for a Mars expedition.

Applied to Mars, one could try this scenario:

Launch 1: 24 tonnes of Hab structure to LEO.

Launch 2: 24 tonnes of part of the ERV to LEO. #1 and #2 dock under remote control.

Launch 3: A 24-tonne Solar Electric Vehicle is lifted to LEO. It docks to the first two and pushes them to Lagrange 1 or 2, which takes six months.

Launch 4: 24 tonnes of other payload (consumables, suits, scientific equipment, etc.).

Launch 5: 24-tonne trans-Mars injection stage (two tonnes of structure and 23 tonnes of liquid oxygen and hydrogen). It docks to #4.

Launch 6: A 24-tonne Solar Electric Vehicle is lifted to LEO. It docks to #4 and #5 and pushes them to Lagrange 1 or 2, which takes six months. The launching of #5 and #6 are the most time sensitive; they have to be separated by a few weeks. Otherwise, the fuel in #5 begins to boil off. Once #5 is docked to #6, the large electrical output of the latter can be used to re-liquefy the fuel in #5.

Launch #7: Four astronauts are launched to LEO in the ERV cabin with a chemical booster able to send them quickly to the Lagrange point. Of the 24 tonnes, 14 tonnes would have to be fuel plus tanks; ten tonnes would be payload. The ERV cabin in Mars Direct has a mass of 11.5 tonnes, plus a 1.8 tonne aeroshell and probably some additional mass in the form of parachutes. But the mass also includes 3.4 tonnes of consumables, most of which could be part of launch # 4 instead, lowering the total mass of the ERV cabin to ten tonnes.

Once #7 arrives at the Lagrange point?preferably a matter of days after #4 and #5 arrive?it docks with the rest of the ERV. We then have 82 tonnes of useful payload at the Lagrange point, plus a booster with 22 tonnes of propellant. The Mars Direct scenario (*Case for Mars,* page 92) figures that two 140-tonne boosters can toss 86.8 tonnes to Mars, so we have achieved almost the same throw weight. Yet we have used seven 24-tonne boosters instead, costing a total of about $600 million (if the $85 million per Proton launch is correct). The Ariane 5 can launch 18 tonnes to LEO for $120 million; the Delta IV heavy, 20.5 tonnes for $140 million. It would probably be best to use several different launch vehicles from several different spaceports so that a disaster at any one would not stop the program. Even at the higher launch costs of the American and European boosters, the total launch cost would be around $1 billion.

I should add parenthetically that if 82 tonnes to the Lagrange point is still not quite enough for the expedition, an eighth launch, bearing an 8-tonne solar electric vehicle and 16 tonnes of cargo, would raise the total of usable payload at the Lagrange point to 98 tonnes, which is quite a bit more than Mars Direct. This would be the ?luxury option? if you want a heavier vehicle bearing a greenhouse, a larger pressurized rover, or whatever.

It is also worth noting that we have also brought to the Lagrange point two very large solar power arrays for the solar-electric vehicles, either one of which could make the cruise to Mars an energy-rich experience, allowing more power-hungry but efficient life support systems, for example.

ASSEMBLY AT LAGRANGE

Once the astronauts arrive at the Lagrange point, they would dock the ERV cabin and aeroshell that bore them to the lower half of the ERV already waiting for them. They would turn around and dock the fully assembled ERV to the cargo module (#4), and shift some of the cargo into the ERV. Then they would pull away and dock the hab (#1) to the cargo module and shift cargo into it. The cargo module?s flimsy structure (1 tonne?) could then be discarded and the ERV docked directly to the Hab. The two loaded vehicles would dock to the trans-Mars injection stage and the latter would fire briefly to send the complex toward Earth. At a few hundred kilometers above the surface, when the complex was moving the fastest, the TMI would fire to push everything to Mars. If the ERV/Hab complex at that point had a mass of 81 tonnes and the TMI stage a dry mass of two tonnes more, its 22 tonnes of fuel could give the complex a delta-vee of 1.06 km/sec; not quite enough for a six month trip to Mars, but probably enough for a seven-month trip.

The ERV and Hab would travel to Mars in tandem, allowing the ERV to serve as an emergency lifeboat if trouble developed on the Hab. One could even run a cable between them and rotate the complex, with each serving as the counterweight to the other for artificial gravity (though under such circumstances, one could not travel from one to the other without stopping the rotation and winding up the cable). As they approached Mars the vehicles would separate and aerobrake separately, then land a few days apart at the same spot. It is conceivable the crew could even split between the two vehicles and land in both, guaranteeing that someone makes it to the surface.

THE LUNAR EXPLORATION VARIANT

There are some obvious variants to this plan worth mentioning. In one, a 24-tonne version of the Hab and a 24-tonne lunar landing vehicle are launched to the Lagrange point by a 24-tonne solar-electric vehicle, then the lunar landing vehicle deposits the hab on the moon. Note that the Mars Direct hab weighs 25.2 tonnes, but that includes 7 tonnes of consumables; a 24-tonne version would have 5.8 tonnes of consumables instead, enough for a lunar exploration crew for quite a long time.

A fourth launch could carry an eight-tonne solar electric vehicle, an eight-tonne lunar lander, and an 8-tonne regolith processing unit able to make 32 tonnes of liquid oxygen and hydrogen a year from lunar ice (this is the Michael Duke proposal). The eight-tonne lunar lander is capable of being refueled on the lunar surface, holding a total of sixteen tonnes, which the regolith processing unit can make (robotically) in six months. Once the lander is fully fueled, it could be launched to the Lagrange point, arriving there with nine tonnes of its original sixteen tonnes of fuel left.

Then a 24-tonne launch from Earth (#5) could lift a ten-tonne cabin (based on the ERV) with four astronauts and a fourteen tonne rocket to LEO. The fourteen tonne stage hurls the ten tonne ERV cabin to the Lagrange point, where it docks to the lunar lander, which uses its nine tonnes of fuel to land it on the moon. While the astronauts explore, the lunar lander is refueled and it can then launch the ERV cabin back on a trajectory that will take it to Earth, where its heat shield brakes it into LEO. Thus, a five-rocket version of the same plan returns people to the moon. This five-rocket version, if done first, could be used to check out the hab and ERV systems.

TO MARS USING LUNAR FUEL

Even better, if a sixth launch carried a second lander and a second regolith processing unit to the moon, when the Mars mission arrived at the Lagrange point it could be ?greeted? by two lunar landers bearing ten tonnes of lunar fuel each. If the landers were docked and used as TMI stages, one could get more payload to Mars with the seven launches necessary to send people to Mars. If techniques for transferring cryogenic fuel between vehicles are developed?perhaps one should say ?when? because the process, while complicated, seems solvable, especially if the two vehicles dock and spin at a very low speed to give them a little bit of gravity?then lunar landers could carry fuel to the Lagrange point and deposit it, and a fuel transport vehicle (basically a big heat shield with tanks) could carry it to low earth orbit. Every six months two lunar vehicles could carry ten tonnes each up to the Lagrange point, deposit nine tonnes each, and use the remaining tonne to return to the moon for more. The eighteen tonnes could be flown to LEO in a four-ton heat-shielded tanker; six tonnes would be needed to push the tanker back to Lagrange for another load. Thus every six months, two regolith processing units and two lunar vehicles could fly twelve tonnes of fuel to LEO. To push 72 tonnes of Mars mission from LEO to the Lagrange point requires about 180 tonnes of fuel. If two regolith processors can move 12 tonnes to LEO every six months, then they can produce 48 tonnes for LEO in two years, and eight regolith processing units can produce 192 tonnes. Thus for four launches of 24 tonnes to LEO (bearing a solar electric vehicle and two regolith processing units each, which are landed on the moon using lunar fuel from the two processors already there), we can fuel a Martian transportation system for many years, and subsequently we would only need three 24-tonne launches (at $85 million each, that?s only $255 million!) to send people to Mars.

Of course, the nuclear reactors being hauled to the moon are pretty expensive, so the fuel produced there is not much cheaper than launching fuel from the earth?s surface. If, instead, astronauts go to the moon regularly and set up solar power arrays on any peaks in perpetual sunlight, nukes would not be necessary and the system would be cheaper than lots of launches from the Earth.

Shaun Barrett · 2002-09-07 00:31:02

Very impressive post, RobS !
In principle, at least, it all sounds doable ... and essentially with off-the-shelf launchers and technology too.
I assume there must be mission planners at NASA who sit and work through similar scenarios, so it must be apparent to them that relatively cheap and technologically 'simple' Moon and/or Mars programs are attainable.
Why is there no enthusiastic public discussion of their findings and why are there no congressional debates on how best to implement such plans?
Posts like yours, Rob, get me all fired up with that old 'gung-ho' spirit, and then I get frustrated and depressed at the total lack of commitment by the people holding the purse strings!

RobS · 2002-09-08 06:59:35

I think there are several "obvious" reasons why a plan like this isn't being implemented yet:

1. NASA is committed to completing the International Space Station, and it has to do that first. Low earth orbit stuff is perceived by the vast majority of the people in NASA and probably by the pub;ic as well as more relevant than the moon or Mars.

2. If this were done using the space shuttle, it would be much more expensive--about four or five times as expensive--and the shuttle is no longer allowed to lift cryogenics in its cargo bay (this was a rule implemented after the Challenger explosion). NASA wants to build a second generation shuttle, anyway, so any plans like this have to wait for that second generation shuttlle.

3. Relevance. We may think humans to Mars is essential, but the general public is lukewarm.

4. Lobbying. Within NASA, is moon people versus Mars people, nuclear versus chemical, weigtlessness versus artificial gravity. Outside NASA, there is the need to make this an international effort.

5. NASA must design with more safety than Mars Direct, and in consequence NASA missions are always heavier than Mars Direct is. NASA missions would require more launches than what I have counted above. This should not be viewed as a criticism of NASA; it's unavoidable. When the Challenger blew up, there was some danger the entire manned spaceflight program would be canceled. If it had been, the Soviets would have scaled back and the Russians (after the fall of the USSR) would have dropped manned spaceflight. If that had happened, we'd be even more frustrated than we are now.

6. Some of this work IS being done at NASA; the Michael Duke et al paper was done by people employed in Houston. It strikes me as the cleverest piece of thinking I've seen, beyond Mars Direct. It's a simple system and uses insitu resource utilization on the moon. That work is still going on.

-- RobS

Phobos · 2002-09-08 19:19:21

Relevance. We may think humans to Mars is essential, but the general public is lukewarm.

I think once we send a mission to Mars and setup a small outpost there people might begin to become more supportive of missions to Mars provided we can avoid the typical "cost plus" bloated funding aspect typical of government. I'd like to see a scientific, unbiased as possible poll to see where the public stands on a mission to Mars. Personally, with the ISS being our most significant manned presence in space, I can see why the public is getting bored and disinterested in the space program. I think people at large would find the Moon or Mars far more interesting targets than LEO.

turbo · 2002-09-08 19:42:15

I remember a little boy who saw Apollo 11 launch, I remember he grew up loving aircraft. I remember he went "down to the Sea in ships". I remember the day he finally started college, and on Friday I will remember the day he graduates with Honors.

That little boy shows grey hairs now, but he has another little boy who turns seven next month.

The grey-haired little boy may not be able to give the dream, but maybe give little boys and girls an entire planet.

Know where to look, Mars is in the night's sky, shining and inviting. Earth has hostile places to life too, like the "Skeleton Coast"

I might be from the United States, but a British slogan fits..."Who dares wins"

Mars is waiting, if we dare
turbo

Shaun Barrett · 2002-09-10 05:12:34

I know exactly what you mean, turbo.
I feel it too!
When you feel something so passionately, it's SOOO hard to understand why others don't feel it the way you do!!

RobS, I'm inclined to agree with Phobos about the relative excitement value of the Moon and Mars v. LEO. I don't think the public has really been given a choice ... they're STUCK with LEO, whether they want it or not!
It's good to hear, though, that Michael Duke et al. at NASA are doing some innovative thinking. I look forward to hearing more about their work in the near future. If you are tuned in to their channel, perhaps you would do us the honour of keeping us informed of new developments, as they eventuate?

RobS · 2002-09-10 13:01:10

I'm afraid I am not tuned into their research. I read a summary on "Romance to Reality," David Portree's incredible website about exploration of the moon and Mars. I hope they publish something kore and we hear about it.

-- RobS

Palomar · 2002-09-10 13:27:35

I remember a little boy who saw Apollo 11 launch, I remember he grew up loving aircraft. I remember he went "down to the Sea in ships". I remember the day he finally started college, and on Friday I will remember the day he graduates with Honors.
That little boy shows grey hairs now, but he has another little boy who turns seven next month.
The grey-haired little boy may not be able to give the dream, but maybe give little boys and girls an entire planet.

*And I remember a little girl, a mere 3 months older than you [I checked your profile], who watched Apollo 11 in awe on the television screen, tried to imitate the astronauts "jumping in slow motion" in her parents' living room, pretended to be in a space capsule all her own while "talking to" the voice of Mission Control coming through the TV audio, and loving space flight thereafter. However, this little girl, now also 37 years old, has no grey hairs, no wrinkles, lines, or crow's feet [and no plastic surgery either, just blessed with really good skin!] and wishes you wouldn't make us sound so ANCIENT, Turbo! Geesh! ??? 37 is YOUNG!!

We'll get to Mars. I'm just wondering when.

--Cindy

RobertDyck · 2002-09-10 14:49:51

We'll get to Mars. I'm just wondering when.

It will never happen if we just wait. We will have to make it happen.

Palomar · 2002-09-11 10:24:11

We'll get to Mars. I'm just wondering when.
It will never happen if we just wait. We will have to make it happen.

*Well of course

By the way, what makes enriched uranium enriched?

--Cindy

RobertDyck · 2002-09-11 13:09:43

Enriched uranium has a higher proportion of U235 vs other isotopes. Natural uranium as it is dug out of the ground is 1% U235, about 99% U238, and a small proportion of other isotopes. Since only U235 is useful in a nuclear reactor, "enrichment" means to increase the proportion of that in fuel. Separating one isotope of an element from another is not easy, the only difference is weight and that difference is slight. Canadian reactors don't use enriched fuel for two reasons: enrichment is expensive, and if you don't have the ability to enrich uranium you can't make bombs. US reactors require 2% U235. Bombs use about 99% U235.

Palomar · 2002-09-11 13:29:23

Robert Dyck [writing on August 29]: Ooh! Someone thinks my messages are out of his league!

*That makes 2 people...you "lost" me a looooong while back.

Robert Dyck: I'm just a computer programmer and wannabe aerospace engineer.

*You could have fooled me. <grin>

Robert Dyck: Ok, so I develop real-time software for embedded systems including flight systems using the same operating system as CanadArm2, but I don't have a degree in aerospace engineering. I learned much of what I know by chatting on the original Mars Society message board and researching the web, reading science and technical journals like Science and The Journal of Propulsion and Power, reviewing my college physics text book, Zubrin's books, a text book on Orbital Dynamics, and technical papers from NASA. Any member could do the same.

*Oh sure...just like anyone can iceskate or do columns of math problems in their heads or paint like Michaelangelo. Honestly...not everyone has a natural aptitude for these sorts of things [one such person speaking <ahem>]. Once the technical talk gets to a certain level, I can't follow it anymore.

--Cindy

RobertDyck · 2002-09-12 18:55:58

Thank you. I also remember watching the Apollo program live as it happened, from Apollo 1 through Apollo 17, Skylab, and Apollo-Soyuz. I wanted to be an aerospace engineer. I am now trying to start an aerospace engineering firm, and use that to enable Mars Society members to participate in projects like building a small probe to Mars. I also volunteered at the Mars Society steering committee meeting at the conference to be the Volunteer Coordinator. That means I match-up volunteers with projects for all members and all projects throughout the Mars Society internationally. Call me busy. But I do seriously want to become an aerospace engineer.

Not all discussion threads on this board will be applicable for all users. Different people have different interests and different aptitude. For example, I haven't been able to follow the civilization & culture discussions, and haven't looked for years. This thread was established to "fix the potholes in Zubrin's plan". That gets into the details of engineering and mission planning. This thread might not match your interest. Although I can read technical papers on Mars geology published in Science, and NASA engineering papers on ion engines, microwave regeneration of reusable CO2 sorbents, structural analysis of all-composite propellant tanks, etc; I couldn't write a poem or paint a picture to save my life. My artistic tallents are restructed to cut-and-paste. I don't have the patience to listen/read to long dissertations on civilization & culture. Different people have different tallents; we need to work together to ensure we can bring all skills necessary to the task of getting to Mars.

Palomar · 2002-09-12 21:58:33

Robert Dyck: But I do seriously want to become an aerospace engineer.

*Looks like you won't have any difficulties.

RD: Not all discussion threads on this board will be applicable for all users. Different people have different interests and different aptitude.

*True.

For example, I haven't been able to follow the civilization & culture discussions, and haven't looked for years. I don't have the patience to listen/read to long dissertations on civilization & culture.

*Does this mean you haven't read my 18th-century Enlightenment posts in the Free Chat folder? {BIG SAD EYES}

RD: Different people have different tallents; we need to work together to ensure we can bring all skills necessary to the task of getting to Mars.

*Indeed. We're like individual pieces of the jigsaw puzzle. I feel I've contributed very well in the Infants & Children Section.

--Cindy

C.COMMARMOND (FR) · 2002-09-13 12:04:04

Hi,

I was not here for a while, so I give a lot of answers.

First to RobertDyck for his answer to mu post of Sept 5 22:10

1 You said Energia has a payload of 22 tons to orbit. I was to the site you indicated and read this:

for The Launcher Energia (of Buran)

LEO Payload: 88,000 kg. to: 200 km
GEO Transfert Orbit Payload: 22 000.

So it is 88 tons to Low Earth orbit. I said 100 tons, but it was from an english site so maybe imperial tons ?

2 Energia M never flight, but is made from 'standard' systems, so I am confident it should flight correctly for 130 metric tons on LEO.

3 From my informations, Angara 5 never flight.

Robs I am sorry, but your scenarii are not usefl since Energia really launches 88 tons on LEO.

And to all of you, don't care about what you now or not know, every one has to give to a Mars project, even if you just know how to do good food, you are usefull. I'd not like to go to Mars and eat synthtic food for 3 years...

CC

Phobos · 2002-09-13 16:52:36

And to all of you, don't care about what you now or not know, every one has to give to a Mars project, even if you just know how to do good food, you are usefull. I'd not like to go to Mars and eat synthtic food for 3 years...
CC

I think people who are skilled at preparing food and growing it will be virtual gods on Mars. I remember reading about how people who stay for long periods in Anartica develop a fanatical interest in food. They go crazy over obscene little details that people normally don't think about. And I wouldn't want to subsist on three years of freeze dried food either. I think agricultural experiments should play a significant role in missions to Mars because nothing will boost morale like biting into a fresh, juicy, vine-ripened tomato after living for a year on freeze dried rations.

Shaun Barrett · 2002-09-13 19:35:18

Food is always important, of course. And there will be something very comforting about taking off your helmet in the Hab, after a day working outside, and smelling the beautiful aroma of a well-cooked meal!
I'm sure Phobos is right that s/he who grows the food and/or prepares it, will be "like unto a God" !!

But, unlike Antarctica in winter, I'm hoping Mars will be far more amenable to frequent field-trips out on the surface. I'm hoping there will be lots of absorbing and challenging things to do, almost all the time.
Maybe in that sense, the claustrophobia-induced manias that plague Antarctic researchers won't be as much of a problem(? )

RobS · 2002-09-14 01:00:58

Regarding the Energia, I quite agree that it is a more practical way to get a Mars expedition on the way than using 24 tonne launches. But the 80-tonne Energia has never been built or launched. There is demand for commercial launches in the 20 tonne range and thus those rockets are mass produced and launched quite often. The point of my posting is that it may very well be that it is easier to go with existing launch equipment, and that it is possible to do so (though not convenient). If an Energia is built for Mars and moon launches, it probably will not be used for anything else, because right now there is simply no demand for launches in the 80 tonne range. Consequently, it may not be a cheap solution to the launching problem.

-- RobS

RobertDyck · 2002-09-14 02:54:46

The launch vehicle Energia was built and launched. It carried the Buran space shuttle once, and the Polyus satellite once. With the Buran, it can carry 30 metric tonnes to 200km orbit. Alone, the Energia can lift 88 metric tonnes to a suborbital trajectory with 200km apogee. With the EUS Energia Upper Stage it can lift 88 metric tonnes into a 200km circularized orbit.

This is the reason I advocate the Energia. It was built, it launched twice, and it can be reactivated more cheaply than developing any new launch vehicle. With the EUS is can lift 88t to LEO, 22t to geosynchronous transfer orbit, or 29.3t directly into trans-Mars trajectory (C3=15). The Saturn V and Russian N1 are gone forever, while Shuttle-C and Magnum have never been built.

I hate to argue with C.COMMARMOND, but the 100 tonne to LEO figure for LV Energia is metric. It is simply the lift capability to a lower orbit. American launch vehicle manufacturers like to quote capacity to 185km, and they sometimes even quote the absolute minimum altitude for orbit: 100km.

Energia-M is a reduced size version of Energia. It had only 2 strap-on boosters instead of 4, and the core module was reduced from 7.8 metre diameter to 7.7 metre, and had 1 RD120 engine instead of 4. With no upper stage, this reduced lift capacity to 34 metric tonnes to 200km circularized orbit. A full size mockup of Energia-M was built, but engineering never proceeded beyond that. If you don't want to believe Astronautix.com you can read the letter from Aleksandr Derechin, Head of International Division, RSC Energia. His letter is available in English and the original Russian.

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Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

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Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

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Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#85 2002-09-08 19:19:21

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#86 2002-09-08 19:42:15

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#87 2002-09-10 05:12:34

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#88 2002-09-10 13:01:10

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#89 2002-09-10 13:27:35

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#90 2002-09-10 14:49:51

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#91 2002-09-11 10:24:11

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#92 2002-09-11 13:09:43

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#93 2002-09-11 13:29:23

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#94 2002-09-12 18:55:58

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#95 2002-09-12 21:58:33

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#96 2002-09-13 12:04:04

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#97 2002-09-13 16:52:36

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#98 2002-09-13 19:35:18

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#99 2002-09-14 01:00:58

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

#100 2002-09-14 02:54:46

Re: Mars Direct Rethought - Fixing the potholes in Zubrin's plan

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