Yes "High Drop for LEO" is next, followed by using Ion thrusters.

The problems with High Drop for LEO are:
a.  The orbit decays so slowly that I had to change my model from a spreadsheet to a computer program.
b.  At 10,000 km the radiation levels are very high so there may be a ban on launching people from that height.  Fortunately there are plenty of cargo launches.
c.  Climbing to 10 times the height will take 10 times as long so the SE operator will want to charge 10 times as much for ribbon time.  A definite trade off between the price of fuel and the price of ribbon time exists.

The weight of fuel may mean that some heavy cargos can only be high dropped - the ribbon will always be weight limited.

Ion thrusters are very fuel efficient but are very slow/weak so they can only be used when the satellite has (nearly) reached orbital speed.  Use them on a LEO launch and the burnt out remains of your cargo will end up in the sea.  It will be interesting to see if solar powered Ion thrusters are viable on High Drop to LEO.

Example 3 – placing a satellite in a Sun-synchronous orbit

A Sun-synchronous orbit is a polar orbit that is in permanent sun light.  Such an orbit requires a big Delta-V.
http://en.wikipedia.org/wiki/Sun-synchronous_orbit

Note:  If you wish to send a satellite to the North Pole the Equator may not be the world's best launch site.

____________________ Testing effect of launching a satellite from the Space Elevator

Satellite into Sun Synchronous (polar) Orbit

Satellite was thrown at a height of 961.800 km whilst raising at a speed of 0 km/h or 0 km/s.
Aiming at a final height of  800 km and an inclination of  90 degrees.
Therefor orbital velocity needs to be 7.452 km/s
The Pay Load weighs 5,500.0 kg, fuel 70,146.0 kg and the structure  1374 kg.
Total mass at launch is 77,020.0 kg.
Thrust of rocket 726 kN and fuel burn rate 219 kg/s.

Location of Space Elevator makes initial inclination  0 degrees and rotational velocity 0.535 km/s.

Command types
F = Freefall for 'Value' seconds
T = Thrust for 'Value' seconds or until the fuel runs out
S = Thrust to Slow down for 'Value' seconds or until the fuel runs out
P = Pitch angle of 'Value' degrees. 0 = rocket is horizontal, 90 = straight up
I = Change Inclination by 'Value' degrees.  Negative to go south


Time  0             Velocity 0.535 Inclination  0 Up velocity  0 Height 961.800

__________ F 4            Freefall for 4 + 1 seconds to prevent harm to cable
Time (s) 4            Velocity 0.535 km/s  Inclination  0 Degrees  Up velocity -0.029 km/s  Height 961.741 km.

__________ P 15.35        Select vertical flight angle
Time (s) 5            Velocity 0.535 km/s  Inclination  0 Degrees  Up velocity -0.037 km/s  Height 961.708 km.

__________ I 90           Fly to the new orbit of 90 degree (Polar) inclination
Time (s) 77           Velocity 0.535 km/s  Inclination  90 Degrees  Up velocity -0.370 km/s  Height 946.915 km.

__________ T 248          Use Thruster to gain required orbital speed
Time (s) 325          Velocity 7.452 km/s  Inclination  90 Degrees  Up velocity 0.032 km/s  Height 800.270 km.

__________ P -90          Bring the satellite to a vertical halt
Time (s) 326          Velocity 7.452 km/s  Inclination  90 Degrees  Up velocity 0.032 km/s  Height 800.301 km.

__________ T 10000        Fire thruster
Time (s) 327          Velocity 7.452 km/s  Inclination  90 Degrees  Up velocity 0.000 km/s  Height 800.317 km.

__________ F 5            Verify that satellite is still in orbit 5 seconds later
Time (s) 332          Velocity 7.452 km/s  Inclination  90 Degrees  Up velocity 0.000 km/s  Height 800.318 km.

Fuel left  0 kg.

*END

From ground release to a height of 961.8 km at 200 km/h takes (961.8/200)*60 = 288 minutes 32 seconds.  
In order to hit the target location the climber has to wait for the launch window which occurs once per orbit giving a worst case delay of 101 minutes.  
During this wait the climber should open its cargo hold or throw off the protective fairing and aim the cargo in the correct direction.  
From throw to final orbit takes 327 seconds (5 minute 27 seconds)
When the launch window arrives the climber throws the payload.  
Total time = 288'32 + 101 + 0 + 5'27 =  394'59 minutes (6 hours 35 minutes)
At throw time the climber needs to accurately correct for all rotations and swings in the ribbon.  
The recoil from throwing 77 metric tons is high and must not damage the cable.


The cargo needs to be throw off the climber to prevent the the rocket motor exhaust burning or contaminating the ribbon. Once thrown the cargo is falling until the end of the burn; if any of the parameters are wrong (out of tolerance) the cargo will be sent to the wrong place or fall back to earth.  The height of the throw, climber upward velocity and angle above the horizontal help determine the final height.  The fuel burnt, engine type and time of throw are the prime determents of the actual orbit.  There are interactions between the parameters.

These simulations used the data from Orion rockets motors.

The Orion 50S XL rocket engine is assumed to be have a thrust of 726 kN and to burn 219 kg/s of solid propellent.  Small thrusters to charge course are needed.  In the above sequences the new orbital direction is selected before the rocket is accelerated because this saves fuel.  The structural mass of the rocket is a guess.

The smaller Orion 50 XL rocket engine is assumed to have a thrust of 196 kN and to burn 56.6 kg/s of solid propellent.  This engine can steer itself.  The structural mass is a guess.

After throwing the cargo the empty climbers need handling.  They could be sent to form part of the counterweight, particularly if they can rise under solar power.  They can fall back to the Earth and burn up in the atmosphere.  Being only a few of hours from the ground they can drive back to the Earth, either separately or in convoy.  By parking the climbers a few kilometres above the LEO orbits and bring them back in convoy about 5 LEO launches can be arranged per day, the main cost being a reduction in payloads of the later launches.

Information about rocket motors – see page 21 of
http://www.orbital.com/NewsInfo/Publications/peg-user-guide.pdf

Example 2 – Sending half a ton to the International Space Station.

The International Space Station lives at a nominal height of 360 km (+40/-5) with an orbital inclination of 51.64 degrees in 2006.
http://en.wikipedia.org/wiki/International_Space_Station

The results of simulation 2.


____________________ Testing effect of launching a satellite from the Space Elevator

Half a metric ton to International Space Station using 2 off Orion 50 XL motors

Satellite was thrown at a height of 377.700 km whilst raising at a speed of 150.000 km/h or 0.042 km/s.
Aiming at a final height of  360 km and an inclination of  51.64 degrees.
Therefor orbital velocity needs to be 7.691 km/s
The Pay Load weighs 500.0 kg, fuel 11,450.0 kg and the structure  842 kg.
Total mass at launch is 12,792.0 kg.
Thrust of rocket 392 kN and fuel burn rate 113.11 kg/s.

Location of Space Elevator makes initial inclination  0 degrees and rotational velocity 0.493 km/s.

Command types
F = Freefall for 'Value' seconds
T = Thrust for 'Value' seconds or until the fuel runs out
P = Pitch angle of 'Value' degrees. 0 = rocket is horizontal, 90 = straight up
I = Change Inclination by 'Value' degrees.  Negative to go south


Time  0             Velocity 0.493 Inclination  0 Up velocity 0.042 Height 377.700

__________ F 4            Freefall for 4 + 1 seconds to prevent harm to cable
Time (s) 4            Velocity 0.493 km/s  Inclination  0 Degrees  Up velocity 0.007 km/s  Height 377.797 km.

__________ P 5.5          Select Pitch angle - slightly upwards to counter gravity
Time (s) 5            Velocity 0.493 km/s  Inclination  0 Degrees  Up velocity -0.002 km/s  Height 377.800 km.

__________ I 51.64        Fly to the same inclination as the International Space Station
Time (s) 19           Velocity 0.493 km/s  Inclination  51.64 Degrees  Up velocity -0.081 km/s  Height 377.221 km.

__________ T 100000       Use Thruster, until out of fuel, to gain required orbital speed
Time (s) 107          Velocity 7.691 km/s  Inclination  51.64 Degrees  Up velocity 0.000 km/s  Height 360.071 km.

__________ F 5            Verify that satellite is still in orbit 5 seconds later
Time (s) 112          Velocity 7.691 km/s  Inclination  51.64 Degrees  Up velocity 0.000 km/s  Height 360.073 km.

Fuel left  0 kg.

*END

From ground release to drive to the wait location at a height of say 376 km at 200 km/h takes (376/200)*60 = 112'48” minutes.  
In order to hit the target location the climber has to wait for the launch window which occurs once per orbit giving a worst case delay of 92 minutes.  
During this wait the climber should open its cargo hold or throw off the protective fairing and aim the cargo in the correct direction.
When the launch window arrives the climber accelerates to 150 km/h and throws the payload at a height of 377.70 km 41 seconds later.
From throw to final orbit takes 107 seconds.
Total time = 112'48” + 92 + 0'41 + 0'107 = 207'16” minutes (3 hours 27 minutes).

At throw time the climber needs to detect and correct for rotations and swings in the ribbon.  Just after the throw the climber has to handle a large change in its centre of gravity.

The empty climber now needs managing.

Comment.  Fine tuning the velocity of the climber is probably easier than accurately adjusting the horizontal angle of the rocket.

The Space Elevator SE can take loads such as communications satellites to Geostationary Earth Orbit (GEO) or send them to other planets.  However most satellites and astronauts only need to get to Low Earth Orbit (LEO), so LEO is likely to be where the money is made.  With a 15 metric ton payload limit the SE can compete with everything but the biggest (and very expensive) rockets.

The SE only achieves orbital speed at GEO so a second stage is needed to boost the payload satellite's speed and give its orbit the required angular orientation.


Example 1 – Launching a 300 kg load to LEO

____________________ Testing effect of launching a satellite from the Space Elevator

Orion 50 XL Motor taking 300 kg to 350 km.

Satellite was thrown at a height of 365.000 km whilst raising at a speed of 147.000 km/h or 0.041 km/s.
Aiming at a final height of  350 km and an inclination of  1 degrees.
Therefor orbital velocity needs to be 7.697 km/s
The Pay Load weighs 300.0 kg, fuel 5,354.0 kg and the structure  420 kg.
Total mass at launch is 6,074.0 kg.
Thrust of rocket 196 kN and fuel burn rate 56.6 kg/s.

Location of Space Elevator makes initial inclination  0 degrees and rotational velocity 0.492 km/s.

Command types
F = Freefall for 'Value' seconds
T = Thrust for 'Value' seconds or until the fuel runs out
P = Pitch angle of 'Value' degrees. 0 = rocket is horizontal, 90 = straight up
I = Change Inclination by 'Value' degrees.  Negative to go south


Time  0             Velocity 0.492 Inclination  0 Up velocity 0.041 Height 365.000

__________ F 4            Freefall for 4 + 1 seconds to prevent harm to cable
Time (s) 4            Velocity 0.492 km/s  Inclination  0 Degrees  Up velocity 0.006 km/s  Height 365.094 km.

__________ P 5.3          Select Pitch angle - slightly upwards to counter gravity
Time (s) 5            Velocity 0.492 km/s  Inclination  0 Degrees  Up velocity -0.003 km/s  Height 365.095 km.

__________ I 1            Fly to the new orbit of 1 degree inclination
Time (s) 6            Velocity 0.492 km/s  Inclination  1 Degrees  Up velocity -0.009 km/s  Height 365.089 km.

__________ T 100000       Use Thruster, until out of fuel, to gain required orbital speed
Time (s) 100          Velocity 7.697 km/s  Inclination  1 Degrees  Up velocity 0.000 km/s  Height 350.065 km.

__________ F 5            Verify that satellite is still in orbit 5 seconds later
Time (s) 105          Velocity 7.697 km/s  Inclination  1 Degrees  Up velocity 0.000 km/s  Height 350.067 km.

Fuel left  0 kg.

*END

The first 50 miles of the ribbon are in the atmospher.  As a guess the solar panels are being folded away to reduce the atmospheric drag of the climber.  The climber may even need to curve to a point like aircraft and rockets.
http://en.wikipedia.org/wiki/Atmospheric_drag

Flat surfaces at 90 degress to the direction have a very large drag.  Formula 1 racing cars use such surfaces as air brakes.

Hello,
       I am Andrew Swallow, a computer progammer by trade.  I live on the south coast of England.

I have been calculating the fuel required to reach Low Earth Orbits (LEO) from the Space Elevator.  I want to check my equations - when calculating the uplift due to rotational velocity should the vertical speed be ignored?

The vertical velocity mostly comes from gravity, the satellite is falling until the end of the burn.  Using the Space Elevator as a stage 1 reduces the fuel required relative to ground launch fuel.

p.s.  No one has objected so I ignored the vertical speed.

We may not need a trafic law until say the third Space Elevator but it is easier to pass one 10 page law than say five 2 page laws.  There is plenty of time to get the law right.

The Space Elevator will need laws of its own.  Where ever possible these should be similar to those of ships and buildings.  In may ways it counts as:[list=1]

• A ship.
• A very tall tower.
• A road/railroad - to the lifters.
• An international airport - to people landing on the ship.
• A space landing/attachment port at Geosynchronous Earth Orbit GEO.
• A satellite launch point along practically the whole of the cable.
• An obstacle in space.

Civilian ships are not authorised to act as air traffic controllers, without such legal authorisation the Space Elevator company cannot have misbehaving pilots arrested.

The ribbon is weight limited so "landings" in space, sea level attachments, departures, launches off the ribbon and movements along the ribbon have to be strictly controlled.  Breaches of these rules can result in crashes and cutting of the ribbon.  Such incidents are likely to result in deaths, injuries and destruction of property.

Without traffic control along the ribbon lifters can crash into stationary lifters, slower moving lifters and lifters going in the opposite direction.  Using contract law and trespass law without criminal sanctions to enforce the rules may not be easy.

Transport companies like railways are normally given "common carrier" status with the corresponding powers, duties and responsibilities.  The Space Elevator's licence will probably need to supply this.  Moving vehicles and rail tracks are subject to inspection - who employes the inspectors (UN/USA/Lloyds Insurance?) and what powers should they have?