A human-powered rocket would be powered by a group of people inside,who are pedaling to provide power for the rocket. The rocket would carry no fuel,it's propellant would be steam. Steam is simply water that's been boiled,so this rocket can be used without polluting the Earth's environment. The lack of environmental pollution is an advantage,and another advantage is low cost. Since it uses no fuel,it's fuel cost is zero. This invention has the potential to be less expensive than any other type of rocket.

Let me describe a typical rocket flight of the future. The rocket itself is more than 250 feet tall,that's as tall as a 25-story building. Most of the rocket's bulk consists of two stages,which can be jettisoned;a large first stage,containing a large steam boiler,and a smaller second stage,which contains a smaller steam boiler. The top of the rocket has the re-entry vehicle,which resembles an airplane. The re-entry vehicle has ceramic tiles on the bottom,these heat-resistant tiles protect the re-entry vehicle from heat while it is re-entering the Earth's atmosphere. The re-entry vehicle has seats for 150 people,who are referred to as astronauts. The leg muscles of these 150 people are the only source of power for the rocket.

Each seat in the re-entry vehicle has a set of pedals on the floor in front of it. The astronaut must place his feet on these pedals,and pedal,in order to produce power for the rocket. This is actually quite simple,like pedaling a bicycle,but there is a warm-up period involved. The warm-up period for a rocket of this size is approximately four days,that means the 150 astronauts inside the rocket must pedal for four days,to provide sufficient power for launch. In order to pedal continuously for four days,the astronauts are split into two groups. One group may be called group A,the other group may be called group B. Group A pedals for 12 hours while group B sleeps for 12 hours,then they trade places,so group A sleeps for 12 hours while group B pedals for 12 hours. This goes on for four days until the rocket is ready to launch. When an astronaut pedals,his pedals turn a generator,that produces electricity. The electricity goes through wires to one of the boilers in the lower stages of the rocket. The electricity is used to boil the water in the boiler. Since there are thousands of gallons of water in each boiler,it would obviously take a long time to boil all of it,that's why the four-day warm-up period is required.

When sufficient steam pressure has been built up,the exhaust valves at the bottom of the rocket are opened,to launch the rocket. Opening these valves causes steam to escape through exhaust nozzles in the bottom of the rocket. The rocket slowly rises into the air,as the steam escapes. At a certain altitude,the steam in the first stage has been used up,so the first stage is jettisoned. Then the steam from the second stage propels the rocket to an even higher altitude. Finally,the second stage is jettisoned and the re-entry vehicle goes into orbit. The astronauts inside the re-entry vehicle can stop pedaling,at this point,and leave their seats. They experience weightlessness,and can float freely inside the cabin of the re-entry vehicle. The astronauts are allowed to bring small cameras with them,and hold the cameras up to the windows to take pictures. They may orbit the earth for several hours,or several days,depending upon how much air and supplies they have on board. They may also launch a small satellite,this is useful because satellites may be used for broadcasting video signals to Earth.

Finally,the pilot announces that the orbital phase of the flight is over,and the descent phase is beginning. He tells the astronauts to return to their seats,and fasten their seat belts.as the re-entry vehicle descends into the Earth's atmosphere,the friction with the air creates heat. The ceramic tiles on the bottom of the re-entry vehicle protect it from heat. As the re-entry vehicle approaches an airport,the landing gear is extended,and the re-entry vehicle lands on a airport runway like a convnetional airplane. Human-powered orbital flights like this may be commonplace,in the future.