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

RobS · 2002-09-14 22:29:50

Robert, is there any price estimate for each Energia launch, and how much is it dependent on the assembly facility at Baikonur whose roof collapsed? Maybe you already answered these questions; if so, I apologize.

88 tonnes to LEO is quite significant. Three such launches equals 264 tonnes, which is equal to two 135-tonne to LEO launches that Zubrin advocates. Or, using solar-electric propulsion as advocated by Michael Duke et al., the 88 tonnes could be divided into a 30-tonne solar electric vehicle and 50 tonnes of payload, and the latter could be lifted to the lagrange point by the former. Two Energias would get 100 tonnes to L1, where the payloads could be mated. Then a third Energia with a chemical third stage could push a small (10 tonne?) capsule with the crew to L1 with about 30 tonnes to spare, which would be enough oxygen-hydrogen fuel to accelerate the whole thing to a delta-vee of 0.9 km/sec; added to 3.1, that's 4.0 km/sec, about enough for a seven month cruise to Mars. So three Energias could easily send Mars Direct on its way.

-- RobS

Phobos · 2002-09-15 01:55:44

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(? )

I'm beginning to wonder myself if Mars will really be all that much worse than Antartica. After all, as long as you live near the equatorial regions you'll still have 24 hour days and the ability to roam around on the surface hopefully in suits that aren't overly complicated or bulky. Personally, I get the feeling that the Antartic winter will make Mars look attractive in comparison. I sometimes wonder though if boredom might not become the evil factor that creates Martian axe murderers. How can you stay in one place for a year or more and still keep yourself constantly occupied or keep from getting into a rut? I guess for some people the constant anticipation that a Martian T-Rex is buried in the next crater might be enough to keep them occupied but some people would probably have to get creative with their spare time. I wonder what kinds of hobbies you could develop on Mars. Perhaps become something of a fossil hunter or perhaps try to grow very small gardens with water you extracted from the regolith? Trying to get to the water and utilize it with crude instruments might be an interesting challenge.

RobertDyck · 2002-09-15 05:35:11

The only price estimate I have is from 1995, before the roof collapsed on the high bays of the vehicle assembly building. At that time the price quoted to NASA was between $60-100 million US dollars to restore infrastructure, and $120 million per launch. Since the vehicle assembly building is where launch vehicles were assembled, it would have to be repaired.

The per launch cost is particulary dramatic if you calculate it per pound to orbit. $120 million / 88,000kg = $1,363.6 per kg, or $3,006.3 per pound. The price to rent the entire cargo bay of Space Shuttle for a commercial launch was $142 million in 1992. NASA shuttle statistics state it can lift 28.803t to 185km orbit, and Astronautix states it can lift 27.5t to 204km orbit. Interpolating to 27.77t to 200km orbit (to compare apples-to-apples), that works out to $5,113 per kg, or $11,273 per pound.

NASA's mass estimates for a crew taxi are 11.34t for an X38 derived vehicle, 2.418t stage inert mass, 11.721t for stage propellant mass, for a total of 25.479t. A capsule is estimated at 6.5t plus 1.588t stage inert mass, and 6.89t propellant mass for a total of 14.979t. That is for a crew of 6. The Russian Soyuz-TM spacecraft carries 3 and masses 3.0t for the descent module (capsule), 2.95t for the service module, and 0.9t propellant. The descent module has life support for reentry, the orbital module has life support for an additional 2 weeks, not necessary for a crew taxi. The orbital module includes the docking collar and rendezvous antenna, but that's relatively low mass. The service module includes solar panels and maneuvering thrusters to perform the docking, and a total 390m/s delta v.

RobertDyck · 2002-09-15 07:34:35

Russia is planning to retire the Baikonur cosmodrome because it is in Kazakhstan. Soyuz and Angara will move to the Plesetsk cosmodrome. That facility is even farther north and was used for polar launches, but it's in Russia. They are talking about removing the disadvantage of orbital inclination change for communication satellites by looping them around the moon. Once Angara is operational they will retire Proton, primarilly because Proton is launched from Baikonur. Although RSC Energia wants to restore their big rocket, it may be difficult to convince the Russian government to invest in repairing the vehicle assembly building in Kazakhstan.

Josh Cryer · 2002-09-15 09:41:15

How can you stay in one place for a year or more and still keep yourself constantly occupied or keep from getting into a rut?

There's one certainty about Mars, and that's that we will always have something to do. Always. From keeping the hydroponic garden in shape, to watching Phobos painted sunrises; I simply cannot imagine being bored on Mars without wanting to be bored.

It's not like you're going to be stuck in a prison cell. In a prison cell, all you have is a bed, a toilet, and perhaps a book or two. Maybe the food would taste like it's from a prison (although I imagine by the time colonization begins, we'll be able to simply beem tastey recipes from Earth- giving us the ablitiy to synthesize flavor in genetically engineered soy), and maybe sharing a toilet and other things of that nature would be annoying. But outside of that, early Martians (and indeed, mere explorers) will have great conditions.

I think the best boredom alleviator (especially for early explorers who may not travel outside of the hab much), would be contact with Earth. Now, I know what you're thinking, ?Wouldn't too much contact with Earth cause massive homesickness??

I don't think so. Watch the Apollo landings. Watch how utterly flabergasted the guys are. We're talking about a totally euphoric experience here. Every day. Every morning, you'll wake up and say, ?Whoa, Mars.? It will take so long to get accustomed to Mars, that by the time you do, you will wish to indulge in boredom. Leaning against a rock, as you stand staring across a flat rock covered valley, your comm off in your space suit.

But think about it, though. How many hobbies are you really giving up? Initally, there are dozens of hobbies you can take with you. From writing books, to taking pictures. From writing music, to building things. Even those poor souls in the inital expeditions (with arguably the least ammount of things to be able to do), will have things to construct.

No, I really don't see people getting in a rut... not forthose reasons, at least.

Phobos · 2002-09-15 17:48:39

There's one certainty about Mars, and that's that we will always have something to do. Always. From keeping the hydroponic garden in shape, to watching Phobos painted sunrises; I simply cannot imagine being bored on Mars without wanting to be bored.

I think it depends on the type of person who ends up on Mars. People who are creative and have the ability to find pleasure in the nuances of things will probably fare a lot better on Mars than people without those qualities. But I agree that Mars won't be a prison and it would be a truly spectacular experience living on an alien world. Come to think of it you'd probably have a lot more work than usual on Mars keeping things ship shape which would probably drain away a lot of potential for boredom in itself.

Palomar · 2002-09-15 18:49:12

There's one certainty about Mars, and that's that we will always have something to do. Always. From keeping the hydroponic garden in shape, to watching Phobos painted sunrises; I simply cannot imagine being bored on Mars without wanting to be bored.
I think it depends on the type of person who ends up on Mars. People who are creative and have the ability to find pleasure in the nuances of things will probably fare a lot better on Mars than people without those qualities. But I agree that Mars won't be a prison and it would be a truly spectacular experience living on an alien world. Come to think of it you'd probably have a lot more work than usual on Mars keeping things ship shape which would probably drain away a lot of potential for boredom in itself.

*Hmmmm. I agree, to a point. However, I'm one of those Forbidden Fruit type of people. If I can have it [whatever], I'm content. If something I really, truly want is out of reach, I WANT IT. It's one thing to say, here on Earth, "No, I don't feel like a movie today...or a Big Mac...or a swim...etc," but on Mars there won't be an option. That subtle difference might become a MAJOR difference for the astronauts of the first missions, even if they are up to their eyeballs in things to do, matters they must attend to, etc.

There's a big difference between "I don't want to" and "I can't". ???

--Cindy

RobertDyck · 2002-09-15 23:53:19

Oh, not to worry. There will be plenty to do on Mars. Astronauts will likely be science types, and that means study. They can get electronic books and PDF copies of technical journals radioed to them (modem). They can also send email requests for digital movies (MPEG), and a catalogue of the latest theatre releases. I'm sure studios would love to send a special MPEG release to Mars of a first-run movie as it's in the theatre. Imagine the publicity of saying an astronaut on Mars requested such-and-such movie. They could also have MPEG versions of the latest episode of their favourite TV shows. MPEG's could be stored on a habitat server rather than an individual workstation so every astronaut could watch at their leisure. There will be email discussions with scientists on Earth analyzing their results. Just because you're on Mars does not have to mean you're isolated. Then there is football in spacesuits, or soccer, or golf, etc. They could go mountain climbing, hiking, or driving. Imagine the ultimate off-road experience in a rover on Mars. You could even give them a small pressure tent the size of a small camping tent, an air mattress and space blanket. It could come with an extended duration life support system, using power from the unpressurized rover. If you set out in the pressurized rover you could just sleep in that like an RV.

Then there is work made fun: geology and search for signs of life. Experiments to use in-situ resources (stuff on Mars) to build stuff for the base. For example, can you make bricks from Mars soil? Can you build a habitat from those bricks that will hold pressure? There is gardening in the greenhouse, and converting Mars soil into fertile soil for the greenhouse. What interesting foods can you cook from food grown in the greenhouse? Can you find permafrost to supply enough water for the greenhouse or brick making?

RobS · 2002-09-16 00:20:43

It sounds like the obvious thing to do would be to build a new Energia facility at Kourou and launch from close to the equator, which would probably boost the throw weight to LEO significantly (10%?). Energias launched from Kourou and the current NASA reference mission (designed for an 80-85 tonne Magnum, so the Energia makes a good substitute) sound like the perfect elements for an international mission to Mars. Maybe too perfect, since NASA will probably want to use American rockets and Kennedy!

-- RobS

RobertDyck · 2002-09-16 00:45:05

You're probably right, NASA will want to launch from Kennedy. However, the US congress will never pay for development of Magnum or any other HLLV. The only reason they paid for development of Altas V and Delta IV Large was to compete against Ariene 5. They didn't like the fact that a non-American organization was taking the majority of the world's launch business and making a profit. Altas V and Delta IV Large were developed to make money and keep that money in America, period. Taxes on the launch industry will pay for government investment. As long as Magnum cannot pay for itself, it will never be built.

So that brings us back to LV Energia, the only launch vehicle that can get us to Mars cost effectively. I had been advocating use of existing equipment until the roof collapsed, but it's gone now. Building a launch facility in Kourou sounds like a good idea, and that lets the ESA into the picture. So how do we make it happen?

turbo · 2002-09-16 09:12:12

Would it be possible to get the ESA to get interested in repairing Baikonur's vehicle assembly building? A joint venture with the Japanese maybe? I'd think the Kazakstan government would be interested.

It bothers me to think of a cosmodrome going to seed, one less possible launch site.

RobS · 2002-09-16 17:54:14

Don't forget that every time a rocket is launched from Baikonur, first stages are dropped on someone's house. No one has been killed yet; no houses have been squashed yet; but livestock have been killed. It is a lousy choice, launching from the desert center of the world's largest continent, and too far north to get into an equatorial orbit as well.

--RobS

RobertDyck · 2002-09-17 05:48:06

Let us not fall into the trap of prejudice against Russia simply because they do something differently than America. Russia and Kazakhstan have a lot of unpopulated land. I'm sure arrangements have long since been made to ensure spent boosters do not fall on any urban areas. The Kazakhs are currently renting Baikonur to Russia, and that would have to include use of all land involved in operations. Personally I am aghast that building #112 would be so badly maintained that its roof collapsed. This destroyed infrastructure for a launch vehicle that was the only operational vehicle in its class, and the only space shuttle other than the American one. From a Mars perspective, that destroyed the only launch vehicle capable of sending a manned mission to Mars without extensive assembly in Earth orbit. It may have been the only launch vehicle with a cost per pound to orbit low enough to make a manned mission affordable. And if you are still worried about wildlife on the steppe getting crushed by a falling booster, realize Plesetsk is also land-locked. Both launch sites are too far north for economical launch of communication satellites, but that only affects orbital inclination. Centripetal force imparted by Earth's rotation is minor; the major propellant cost is inclination change necessary when your launch site is not beneath the desired orbit. A launch to Mars could depart from any inclination; that inclination is lost once you leave orbit. If an international mission to Mars is going to happen, we must respect all partners involved and make use of all assets they bring to the project. But all of this is moot if no one is willing to pay for repair of building #112, the vehicle assembly building.

RobertDyck · 2002-09-19 03:07:31

RobS, we obviously disagree on Energia. I'm sorry if my response sounds touchy, but I've encountered a number of people who want to belittle it, or before the accident tried to claim it was completely and irretrievably destroyed. However, since availability of it or any HLLV are highly suspect, would you be interested in working on a mission plan using existing launch vehicles? The mission plans we described on page 3 do sound similar.

I would like to propose several mission assumptions:
- 4 astronauts
- solar-electric propulsion
- expendable reentry capsule masses 4 tonnes
- use reentry capsule as crew taxi
- rendezvous in highly elliptical geosynchronous transfer orbit

How few launches can we reduce it to? How much existing equipment can we use to eliminate development cost?

RobS · 2002-09-19 11:39:05

Actually, Robert, I think we agree. You have convinced me that Energia is the best choice (barring political issues, which unfortunately will affect the choice). I would like to work on a redesign with you; it would be fun. I suppose we would want to start with the NASA reference mission? The problems is that I am no expert on figuring out masses; I have to rely on existing guesses and make extrapolations from them.

Here's a question for you: if a nuclear reactor will be needed on the Martian surface, would it make sense to use that same reactor to power a nuclear-electric (rather than a solar electric) vehicle? Unfortunately, I am uncertain how one would go about figuring out the answer. One would have to consider the masses of heat radiators (which may have to work differently on the surface than in space) and the problem of moving around something that, once it is turned on, has become radioactive. Reactors are not particularly radioactive before being activated, I gather.

Another, important question: are we talking about electric drive to, say, a Lagrange point (delta-vee, 3.1 km/sec), and then chemical propulsion thereafter? This is reasonably fast and mass-efficient.

-- RobS

GOM · 2002-09-19 13:10:00

Oh, not to worry. There will be plenty to do on Mars. Astronauts will likely be science types, and that means study. They can get electronic books and PDF copies of technical journals radioed to them (modem). They can also send email requests for digital movies (MPEG), and a catalogue of the latest theatre releases. I'm sure studios would love to send a special MPEG release to Mars of a first-run movie as it's in the theatre. Imagine the publicity of saying an astronaut on Mars requested such-and-such movie. They could also have MPEG versions of the latest episode of their favourite TV shows. MPEG's could be stored on a habitat server rather than an individual workstation so every astronaut could watch at their leisure. There will be email discussions with scientists on Earth analyzing their results. Just because you're on Mars does not have to mean you're isolated. Then there is football in spacesuits, or soccer, or golf, etc. They could go mountain climbing, hiking, or driving. Imagine the ultimate off-road experience in a rover on Mars. You could even give them a small pressure tent the size of a small camping tent, an air mattress and space blanket. It could come with an extended duration life support system, using power from the unpressurized rover. If you set out in the pressurized rover you could just sleep in that like an RV.
Then there is work made fun: geology and search for signs of life. Experiments to use in-situ resources (stuff on Mars) to build stuff for the base. For example, can you make bricks from Mars soil? Can you build a habitat from those bricks that will hold pressure? There is gardening in the greenhouse, and converting Mars soil into fertile soil for the greenhouse. What interesting foods can you cook from food grown in the greenhouse? Can you find permafrost to supply enough water for the greenhouse or brick making?

Sounds great!

When do we leave?

RobS · 2002-09-19 14:15:28

Actually, Robert, it occurs to me that the question "how few launches can we reduce it to?" has already been answered (though I am in favor of thinking about the question anyway). The NASA Reference Mission's solar-electric variant can be done using three Magnums, and the Magnum has a slightly smaller throw weight than an Energia (85 tonnes versus 88), so we know three Energias can do it.

Zubrin, in *Mars Direct,* page 105, says that nuclear-thermal rocketry can throw 60-70% more to Mars than hydrogen-oxygen, and solar-thermal can throw 40-50% more. If you want to keep the throw weight constant, this translates into smaller launchers: thus a 140-tonne launcher for hydrogen-oxygen can be replaced by (roughly) an 84-tonne launcher using nuclear thermal and a 97-tonne launcher using solar-thermal. Solar-electric should be somewhere between the two at worst, and more likely it is closer to nuclear-thermal. So an Energia, with an 88-tonne throw weight, is about right.

If the Michael Duke et al model for lunar transportation is assumed, a 29-tonne solar thermal unit can push 58 tonnes to the Lagrange point, where a small chemical stage can push something like 42 tonnes to trans-Mars injection (this is rough and off the top of my head). Zubrin's chemical booster pushes 46.2 tonnes of cargo and 40.6 tonnes of manned vehicle to Mars (less for people because they have to go faster).

So again, an Energia is about right.

Then there's another trick to remember: Mars Direct presupposes one launch the first opposition and two the second and each subsequent opposition. If we presuppose two launches during the first (unmanned) opposition, we can land a cargo pallet on Mars in the 15-25 tonne range, in addition to an ERV. Even if the throw weights to Mars were somewhat less with Energia/solar electric, that extra launch makes a big difference. Subsequently two launches are more likely to be enough because (1) after the first crew arrives, you already have two reactors and don't need more; (2) you probably have access to water, and thus do not need to import hydrogen feedstock; (3) you already have a hab and lots of stuff; etc.

-- RobS

RobertDyck · 2002-09-20 00:07:37

Actually when I asked how many launches we can reduce it to using existing launch vehicles, I was referring to Atlas V, Delta IV large, Ariane 5, Proton, Angara 5, Space Shuttle, and smaller launch vehicles. What would it take if Energia is not available?

We can minimize fuel to lift the spacecraft from LEO to staging orbit by using an elliptical orbit. The higher the apogee the less fuel required to escape Earth orbit. Raising the perigee is just a waste of fuel. Geosynchronous Transfer Orbit (GTO) has an apogee equal the altitude of Geosynchronous Earth Orbit (GEO). Staging orbit does require an apogee equal to GEO, but I would suggest that or higher to minimize fuel required for insertion into trans-Mars trajectory. The perigee could remain the same as LEO. Insertion into a Lagrange point requires circularization.

RobS · 2002-09-20 15:16:23

I've been thinking about your idea in and around office work, a committee meeting, and a noisy four year old most of yesterday and today, and I have come up with a simple strategy for figuring out what masses we need. This is very rough, but it seems to work reasonably well. I have tried calculating masses needed to launch a certain amount of payload to Mars and the numbers I come up with never match those of the professionals. Usually my numbers come up too optimistic; the launch rockets end up being smaller than the numvers the professionals arrive at. So, instead of taking the problem as a physics problem to solve, I've taken the approach that it is a numbers game that has to reach the same results as the professionals. So, here's a "formula" that roughly does this:

#A. Payload to the Martian surface. Mass = 1 unit

#B. Landing legs, engine, parachute, fuel, aeroshell.
Mass = 1/2 unit

#C. LOX/LH2 propellant, tanks, engine to accelerate #A and #B from near escape to 3.8 km/sec (Hohmann transfer plus midcourse correction). Mass = 1/2 unit

#D. LOX/LH2 propellant, tanks, engine to accelerate #A and #B from near escape to 4.4 km/sec (fast transfer for crew plus midcourse correction). Mass = 1 unit

Note that if you just want to put a payload in Martian orbit, it is equal to #A plus part of #B (about 1.3 units)

Propulsion systems to get A, B, and C to escape velocity OR to get A, B, and D almost to escape:

#E. Solar Electric (solar panels, tanks, propellant). Mass = 1 unit

#F. Solar or Nuclear Thermal (solar panels and solar engine or nuclear engine, tanks, hydrogen propellant). Mass = 2 units

#G. Chemical (LOX/LH2) (fuel, tanks, engine). Mass = 3 units

EXAMPLES:

1. Placing a 25.2 tonne hab plus 4 crew on the Martian surface using chemical propulsion: #A + #B + #D + #G = 5.5 units; 25.2 x 5.5 = 138.6 tonnes. This is very good agreement with Mars Direct, where 25.2 tonnes is thrown to Mars by a 140-tonne to LEO booster.

2. Placing a 28.6 tonne ERV on the Martian surface using chemical propulsion (via Hohmann trajectory): #A + #B + #C + #G = 5 units; 28.6 X 5 = 143 tonnes. Again, in good agreement with Mars Direct, where 28.6 tonnes is thrown to Mars by a 140-tonne to LEO booster.

3. Throwing 46.2 tonnes to Mars (Hohmann trajectory). This is equal to #A and #B and requires #C plus #G. Cargo is 1.5 units, propulsion is 3.5 units. A unit thus is 46.2/1.5 = 30.8 tonnes, 30.8 X 5 = 154 tonnes. For Mars Direct, this requires a 140 tonne to LEO booster, so the calculation comes out somewhat high.

4. Throwing 40.6 tonnes to Mars (fast trajectory). Again, 40.6 tonnes is 1.5 units, so a unit is 27 tonnes; throwing it requires #D plus #G or 4 more units, Thus the total mass to LEO is 5.5 units x 27 = 149 tonnes, a bit high, but close.

5. Placing a 25.2 tonne hab on the Martian surface using solar-electric propulsion and fast transfer : #A + #B + #D + #E = 3.5 units; 25.2 x 3.5 = 88.2 tonnes. Energia! Of course, this does not get the crew on board; they’ll have to be flown up after the solar electric engine has done its work, and before the chemical engine in #D kicks the complex to Mars.

6. Placing a 28.6 tonne ERV on the Martian surface using solar-electric propulsion (via Hohmann trajectory): #A + #B + #C + #E = 3 units; 28.6 X 3 = 85.8 tonnes. Energia again!

Anyway, you get the idea. This seems to work pretty well; it’s at least in the right ballpark.

If the payload we want to land on Mars is in the 25-30 tonne range, we will need a launcher capable of putting at least half that into orbit; say, 17.5 to 20 tonnes. But even then, we would have to split the ultimate cargo in half, which would be very inconvenient and might require assembly in low earth orbit; and we would have to split the solar-electric vehicle in half, which raises the problem of launching liquid hydrogen into orbit and not using it right away. So I think we need a launcher able to launch 1 unit of Mars cargo to low earth orbit, which would also be able to launch the solar-electric vehicle intact.

Robert Dyke seems to be our expert about launchers; Robert, what are the real choices? Energia is best, but if it is unavailable, then what?

The other question to consider: can we make the hab and ERV lighter in mass than Mars Direct does? If we use an inflatable hab, a Mars Ascent Vehicle, and an Earth Return Vehicle (from 1-sol elliptical Martian orbit), we can probably reduce the 1 unit of surface cargo to 18-20 tonnes. But now we are sending three complexes to Mars instead of 2, each requiring at least three units of mass, so that’s a minimum of 9 launches instead of 6.

-- RobS

RobertDyck · 2002-09-21 13:48:52

I compiled a short list of launch vehicles available today. There are several smaller vehicles; I just included the big ones and vehicles that could carry a crew taxi. I left out the Angara and upgrades to Ariane 5 since they aren't available yet. Oribital inclination for LEO is only important to rendezvous payloads from different launches. If you want to assemble something in Earth orbit, the pieces must have the same inclination and altitude. I don't know how to format a table in a message here, so I created a web page here.

RobS · 2002-09-22 01:30:58

Thank you, Robert, for the chart of launch vehicles at the Winnipeg Mars Society?s web site. One suggestion I wish I had made: it would be helpful to list the launch capacity to geosynchronous orbit, which is a common piece of information often given. The delta-vee from low earth orbit to geosynchronous orbit is 4.1 km/sec; the delta-vee, low earth orbit to Mars (Hohmann orbit) is 3.8 km/sec, and when one includes midcourse corrections, it?s 3.9 or 4.0. So basically the launching capacity to Mars and to geosynchronous orbit is the same. This is good news of sorts, because it means that commercial forces are at work to drive down the cost of launch to Mars.

Regarding your concern about using the Lagrange point, I don't think it requires significant circularization because you aren't in an "orbit." Rather, you are in a quasi-escape situation. You're sort of hovering at apogee. But that's not an important issue.

RobS

RobS · 2002-09-22 01:42:15

Regarding revision of the Mars Direct mission, I would like to propose the following approach and scenario:

RobertDyck · 2002-09-22 10:39:11

Actually, Space Shuttle was able to lift 27.85t to 204km orbit before the Challenger accident. Improved safety equipment reduced lift capacity to 24.4t to 204km orbit. In preparation for constructing ISS, the Space Shuttle was upgraded. This included replacing the aluminum alloy external tank with an aluminum-lithium alloy, replacing CRT's in the cockpit with LCD displays, replacing platinum based fuel cells with proton transport membrane fuel cells, etc. The result was increased lift to 27.5t to 204km orbit or 28.803t to 185km. To compare with Russian launch vehicles I calculated its lift to 200km.

Delta has several configurations. The largest one is Delta V with a 5 meter diameter fairing, 5 strap-on boosters, and 1 upper stage. The 3 digits following the model designate all this: 5 for fairing, 5 for boosters, 1 for upper stage, makes 551. There is a Delta V Large 552, but the second upper stage does not add lift capacity to LEO. It would be used to lift a smaller payload to a higher orbit.

Since you asked about Japanese and Chinese launch vehicles, I added the Japanese H-2 and Chinese Long March 2E and 2F. The Japanese booster is the most expensive. The Chinese are reportedly working on a new line of launch vehicles, the CZ-5. The CZ-5-5.0 would be similar to the Ariane 5 core, and could have 2 to 8 strap-on boosters. With all 8 boosters it is supposed to be able to lift 40t to 200km orbit, but it is still in development; scheduled for service 2008. The Japanese are also experimenting with a reusable launch vehicle based on the DC-X, and China is experimenting with an RLV based on Kistler's K-1. Both RLV's are a couple decades away from service.

I didn't include Angara for a few reasons. I thought we were restricting this to existing launch vehicles. Magnum will probably never be built, Energia requires a new manufacturing facility for its core module as well as either repairing the vehicle assembly building or constructing a new launch facility. Shuttle-C and Ares will definitely never be built. Long March CZ-5 is so far in the future it could be cancelled. Upgrades to Ariane 5 and production of Angara will probably be done, but aren't available yet. The configuration "Angara 5A" described in Astronautix does not match the configurations "Angara 5" and "Angara 5-UOHB" described by International Launch Services. It appears the UOHB upper stage will be larger than that described for "Angara 5A", but ILS does not give exact lift figures or prices.

I haven't included direct lift to geosynchronous transfer orbit because I thought we were designing for launch to LEO then spiral out using solar-electric propulsion.

For reentry capsule, I made a mistake. Based on the Soyuz descent module, capsule mass should be 1t for each astronaut. That would make a 6 crew capsule mass 6t, or a 4 crew capsule mass 4t.

RobS · 2002-09-22 23:11:11

Thank you, Robert, for the additional launch vehicle data. The Japanese booster was smaller than I thought, and thank you for the additional information about the shuttle. They keep improving it; it may very well be flying by the time people go to the moon again or to Mars the first time!

And thank you for the revised capsule data. I will combine it with a revision of the MAV/ERV aspect that occurred to me today (well, I remembered an idea of yours). I have had some new additional ideas since my posting yesterday about using solar power on the Martian surface and about using more cargo flights and fewer large flights (because each one can deploy solar panels and launching the entire package in one blastoff is probably simpler). Maybe by tomorrow I'll be able to propose another revision of this plan ("Mars, 24 tonnes at a time"?).

-- RobS

turbo · 2002-09-23 09:18:10

Hi Rob and All!
I'm kind of curious about the power generation issue. Besides the photovoltaics, would it be possible to use something like a radiometer in the thin Martian air? I think radiometer is the right name, it's one of those light bulb looking things with fins inside. One side of a fin is white, the other black, and the idea is sunlight causes uneven heating to make the whole thing spin.

Shot in the dark I know, but a possibility?
t

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#101 2002-09-14 22:29:50

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

#102 2002-09-15 01:55:44

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

#103 2002-09-15 05:35:11

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

#104 2002-09-15 07:34:35

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

#105 2002-09-15 09:41:15

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

#106 2002-09-15 17:48:39

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

#107 2002-09-15 18:49:12

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

#108 2002-09-15 23:53:19

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

#109 2002-09-16 00:20:43

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

#110 2002-09-16 00:45:05

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

#111 2002-09-16 09:12:12

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

#112 2002-09-16 17:54:14

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

#113 2002-09-17 05:48:06

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

#114 2002-09-19 03:07:31

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

#115 2002-09-19 11:39:05

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

#116 2002-09-19 13:10:00

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

#117 2002-09-19 14:15:28

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

#118 2002-09-20 00:07:37

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

#119 2002-09-20 15:16:23

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

#120 2002-09-21 13:48:52

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

#121 2002-09-22 01:30:58

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

#122 2002-09-22 01:42:15

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

#123 2002-09-22 10:39:11

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

#124 2002-09-22 23:11:11

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

#125 2002-09-23 09:18:10

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

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