These are notes concerning the design of a system for traveling into space from the earth. It is based on the GURPS vehicle design rules with alterations where they clearly depart from known physics.

The system is best deployed near the equator where the 1000mph (or so) rotational velocity makes it easier to achieve orbit. The reusable portions of the system have a cost less than 10 billion dollars and the cost to orbit varies between 1 dollar/pound and 100 dollars/pound depending on the size of the object being lifted. The maximum lift capacity exceeds the space shuttle by a good margin.

There are three main stages to a takeoff. First, the maglev lifter is accelerated on the maglev rail to 1000mph at a little over 1 gravity for 22 seconds. Then, a ramjet powered plane takes off from the lifter. The maglev lifter slows down and heads back to the origin point on a second track.

The ramjet powered plane lifts off carrying a heavy load at 1000 mph. It accelerates to 6000mph on a suborbital path. At the top of this arc, the plane releases it's cargo, a rocket. The acceleration is at about 1 gravity for 300 seconds, followed by nearly 2 gravities for a minute while the afterburners kick in. After releasing it's load, the ramjet glides for a couple hours, returning and landing where it took off.

There are three possible third stages. All of them burn for about 6 minutes at something between 1 and 5 gravities providing sufficient delta-v to reach low earth orbit. The lifter design is just an automated rocket capable of delivering 85000 lbs. It is not reusable as a lift rocket, but it can easily be reused in the design of a space station or with the space bus. The space shuttle delivers 35000 lbs and 10 people into low earth orbit. It can land and is fully reusable. The space bus lifts into orbit carrying people, but it has an altered design - it will never land on the earth again. Instead, the space bus is meant for exploration of the solar system. Given 6 other space lifters which have been refilled by 30 empty space lifters, the space bus has sufficient delta-v to reach and explore the moon, mars, and venus.

Summary of earth-to-space system
Item number construction cost total cost maintenance cost, daily energy cost, per use lift capacity cost/lb reusable
mag lev rail 1 100000000 100000000 2404 490 1766261 y
mag lev lifter 2 1000000000 2000000000 10000 490 663904 0.000738 y
ramjet bus 10 100000000 1000000000 2168 27577 500000 0.055154 y
space lifter 36 3000000 108000000 405 123000 85000 36.74118 n (although "yes" in a space station or space bus design)
space shuttle 10 4000000 40000000 472 123000 34000/10 people 0.276423 y
space bus 1 3000000 3000000 405 738000 10 people 367.4118 y
The maglev rail gives us two advantages, both of which decrease the weight of the lifting plane. 1) we can use a ramjet engine in the plane design because we achieve it's threshold speed (375 mph). 2) The maglev rail helps us get off the ground. Although landing is not a problem, taking off while fully loaded requires a lot of lift, which we only achieve at the high speeds which a maglev rail provides.

The ramjet design uses a lifting body, because this is significantly cheaper and has a lower drag than a winged design. The "cheaper" aspect may or may not be an artefact of the design rules, but the decrease in drag probably is not.

Use of a high altitude/high speed plane achieves two things. First, we can reach 1/3 of orbital velocity very cheaply. Second, we can (essentially) leave the atmosphere. Because we release the third stage in a very low pressure atmosphere, it is not very important that the third stage be aerodynamic. This results in various cost and weight savings for the third stage.


It is unclear that a maglev rail can be made to go fast enough because it hasn't been done before. Nonetheless, there seem to be no reasons why it might not work. Non-maglev trains have reached 300mph.

It isn't clear that ramjets can actually reach 6000mph as suggested by the rules. The SR-71 achieved over 2000 mph using 1960s era technology.

The loaded maglev train is a somewhat heavier than you might hope for. Other train cars have been within a factor of 2.

The loaded ramjet plane is slightly heavier than an Boeing-777.