An EUS derived depot would be able to store about 125 tonnes of propellant.

Since it would be a lot safer, cheaper, and more convenient to transport water to a space depot than propellant, I believe that propellant depots should manufacture and liquefy their propellant from water using solar or nuclear energy.

So I’d also make the EUS derived propellant depot capable of also storing about 200 tonnes of water.

This would allow private companies to initially transport water from Earth to propellant depots located an EML1, for instance. But once lunar water is being exported to propellant manufacturing depots at EML1, Earth water launches might be restricted to propellant depots located at LEO.

However, lunar water exported to depots at LEO might still be competitive with water being launched to from Earth.

Marcel

One of these days I need to learn the rocket equation and run the numbers myself. It seems with us at 1 g, escape velocity be greater than 25K mph, fuel being X amount of mass, chemicals when mixed explode providing Y amount of energy, livable container being Z amount of mass,… LH2 fuel is pretty much only way to go.

>Heinlein quote about Earth orbit being “halfway to anywhere”

This is a catchy phrase but does it make sense? We have lots of things in earth orbit but taking it to the next level has been much more difficult (there’s something many of us are missing). I’m thinking Heinlein’s quote is great for story telling but bankrupt like “it takes money to make money” (if you know what that means then you already know this expression and can make money, if you don’t then can only repeat the quote).

Congress did not design the SLS. They directed a Super Heavy Lift Vehicle be constructed. Since the SLS going direct to the Moon is a direct threat to the NewSpace LEO business plan, this has generated literally thousands of misleading “death-to-SLS” comments.

Not that simple.

1. “I am assuming ~200 m/s per month in my calculations which is roughly correct.”

You are leaving out the sail would be miles in diameter to transport only a few tons at most (roughly correct). It is completely impractical.

“a solar sail spacecraft that is durable enough to last decades -could dock a large number of times say 52 times on the way to Mars?”

Mars is a dead end.

I’d argue that what we have now is closer to commercial practices involving the provision of services in that the customer specifies the service he’s buying, not the process by which it is to be created. If I employ a service provider, I’ll use landscaping as the example, I’m not going to demand on specifying the make of the machinery he uses, who he employs, where he bases his operations, where he buys his gas from, who his accountant is to be etc, if I were to meddle in his business in that way, guess what, he’s going to end up charging me more and I have no doubt he would end up providing me with a more expensive but inferior service. I don’t know his business as well as he does, the government doesn’t know rockets as well as SpaceX or ULA does.

I’d argue that by meddling in the way it has in the past the Government has created a culture within aerospace companies that has cost the American tax payer billions – for nothing other than to give politicians opportunities to play politics. Politicians love power, love exercising power, love to be seen as important. It’s why they chose that occupation.

[“I am sure there is a way to genetically engineer flying unicorns also. But unfortunately solar sails won’t be doing any heavy hauling in a space program. You want to move stuff around try using an alloy fabric parachute a couple thousand feet in diameter and some atomic bombs. That would actually work. “]
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Thank you for the correct reference I knew this was a common knowledge approach but did not know the history of the first to come up with it. Gerard K. O’Neill is the owner of the idea to use a rail gun or similar technology to launch mass to orbit from the moon or mars. Likewise aero-braking and parachutes to slow spacecraft re-entering Earth are good ideas discovered by others.

Regarding unicorns I explained in detail how it works in the video. I appreciate I am making a large claim and its very easy to say that it is impossible to rapidly transit to Mars without consuming fuel.

But it can be broken down to very simple steps with yes or no answers.

1) do you believe solar sail powered spacecraft provide delta V without consuming Earth sourced fuel? I am assuming ~200 m/s per month in my calculations which is roughly correct.

2) do you believe the law of conservation of momentum applies if one space ship kinetically ejects another space ship? How about if it ejects many small space ships one after the other at a velocity of 250 m/s which is about 900 km/hr? This is an ISP of ~25.5 s

3) Do you believe its possible to rapidly accelerate in a energy efficient manner using a 25.5 seconds ISP fuel given enough mass?

4) do you believe the laws of physics allow a solar sail spacecraft that can navigate to a docking station and then re-package its solar sail into a compact form factor?

5) Do you believe physics permits a spaceship from Earth after reaching a docking station to re-load the smaller spacecraft from a docking station thus reusing the fuel?

6) Do you believe its possible to have a solar sail spacecraft that is durable enough to last decades?

7) Do you believe the large space ship could dock a large number of times say 52 times on the way to Mars?

If you answered yes to these questions we are already in agreement. New ideas always sound strange and unworkable, I invite you to invest 15 minutes of your time to understand how my idea works.

Talk starts 33 min in
http://www.ustream.tv/recorded/86070557

Docking 52 times each way allows 2 missions worth of infrastructure to eliminate the need for fuel and reduce the kg to LEO per kg to Martian orbit by 80% for the lifetime of the smaller spacecraft which could be decades.

Sure the small spacecraft are expensive relative to rocket fuel, Sure there are technology hurdles that need to be solved. But 100 years from now this is how it will be done unless em drive or some other fantastic advance renders it obsolete.

By that definition, we’ve always had “commercial” spaceflight, as every space flight project since Mercury has been bid on by a wide variety of aerospace companies (in fact, by many more that existed then, under the “socialist” model, than exist now under the allegedly free market “New Space”). New technology was jointly developed by NASA and those contractors. So now that’s it’s “established” and proven by 50 years of useage, why should the feds pay for a new rocket and spacecraft development?

I know that you New Space guys love to redefine terms, but I’m not buying it.

The important question is “Has NASA gotten deals that are acceptable to them and to the service providers in a competitive market place?”

It seems they have, so unless there’s some sort of under the table corrupt dealing going on it counts as legitimate business, there’s nothing “crony capitalism” about it unless you’re claiming that other potential service providers were either unfairly excluded from the bidding process, or unfairly treated when it came to the selection of the successful bidders.