Sunday, May 29, 2011


Avoid wind and weather 
of lower atmosphere 
to shield vehicle and contents.
Lofstrom’s Launch Loop (LLL)
In 1985, Keith Lofstrom published a paper which proposed a novel method of non-rocket launch of payloads into Earth orbit and beyond. His concept, Launch Loop, would use mag-lev, to 3×G accelerate 5 ton payloads as fast as needed to leave Earth surface and enter specific Earth orbits.

LLL is a huge proposed structure, best located along the oceanic equator, well away from inhabited areas. It would rise 80 km above the ocean to form a 2,000 km long "track" then descend back to the ocean to a "turnaround point". Then, the loop reverses course back up to the track and back to starting point. The "loop" will be a vacuum tube, known as the "sheath" along the whole length of above structure. Floating inside the evacuated sheath is a thin continuous, cable like "rotor", about 5 cm (2 inches) in diameter, moving around the 4,000 km circumference at 14 kps.  At this enormous speed, the iron rotor produces powerful magnetic eddies to power payload's 3×G acceleration on the track high above the clouds.
Tether Touches the Sea.
Dr Bradley C. Edwards is the originator of the Space Elevator (SE) concept. He published papers in 2000 and 2003 which project the tether extending from the ocean based platforms (now called "Marine Anchor") as shown.

From the Up-Link Marine Anchor, original SE concept called for TETHER CLIMBERS to start a long journey to the GEO Node, 35,789 km straight up.  As Up-Link climbers go higher, Earth gravity decreases greatly; so climbers could use relatively small motors. At an average speed of 220 kph, expect Up-Link trip from surface to GEO to take about about 7 days.
Problems include: 
1) Stored energy (i.e., batteries, fuel) is very heavy; so, the most practical power solution involves exclusive use of real time, solar power.
2) Night time obviates solar power; so, climber must cease climbing and hibernate during periods of darkness.
3) Inevitable wind and weather will hinder solar panel deployment during first 40 km (or so) of  upward trip.

Tether Touches High Platform
In 2015, ISEC addressed weather problem in ISEC's 2015 EarthPort Final ReportSE's High Stage One enables climbers to avoid large weather forces in the Earth’s lower atmosphere. It is easily erected to support a platform at 40 km altitude where payloads transfer from a rail car to a tether climber for upward travel towards the GEO node. 

High Stage One adapts Lofstrom's Launch Loop (LLL).  It is roughly 1/12 the mass, but it uses the same concept. LLL uses magnetic levitation (mag-lev) to impart high speeds to rotors inside vacuum tubes; as a result, High Stage One structure supports its own weight with the kinetic energy of the moving loopThe platform avoids wind and weather in lower atmosphere to deploy solar panel array unhindered. However, tether climber must still endure a long, slow trip to GEO; thus, contents will likely gain many deadly REMs from the radiation belts.  
Ride the Beam  
TE recently posted blog entry proposing ion beam propulsion as a more practical, non-rocket solution to achieve orbit. If we trade physical tether (climber ascending ribbon made from CNTs, strongest material ever, but still prone to inevitable breaks) for virtual tether (beam rider vehicle on power beam not of laser light but of high speed protons, much more momentum); then, SE can greatly reduce: 1) travel time, 2) boredom, 3) radiation risk.

TE proposes ion beam from base station particle accelerator to 0.1 G accelerate vehicle to midway to GEO, about 17,900 km above Earth (estimate travel time about 100 min). TE assumes another 100 minutes to 0.1 G decelerate from midway to GEO node. For ion beam to leverage High stage One platform, TE proposes alternatives in following frames.
1) Static Vehicle Atop the Platform 
Directly impact .1 c particles onto static beam rider which sits on top of High Stage One platform.

SAFETY MEASURE:  Use well engineered parachute solution to ensure safe surface impact if vehicle falls to surface.

PROBLEM: This method must overcome vehicle's inertia for upward propulsion.
2) Moving Vehicle Rides the Platform  
Extend High Stage One platform for shortened version of LLL. EXAMPLE: Diagram shows a platform extended to a 6 km track.  At 3G acceleration, a vehicle could achieve 1,500 kph by 3 km with remaining 3 km for vehicle to achieve vertical flight. During vertical flight, vehicle could ride ion beam with advantage of much less inertia.

---Greater mass - more difficult to erect to height of 40 km.
---Greater cost - more difficult to construct and maintain.
---More complex - combine launch procedure with ion beam propulsion.
3) Reversible Cyclotrons: Bidirectional Propulsion
Since Earth's gravity will decrease as vehicle gains altitude, TE assumes cyclotron augmentation is needed only for short time at beginning of acceleration.   Thereafter, ion beam must both propel Beam Rider to midway, and it must also provide on board tokamak with sufficient protons to store for deceleration. After vehicle passes midway mark to GEO Node, cyclotrons will reverse direction of output streams to slow down vehicle to arrive at GEO Node with zero velocity.

PROBLEM:  From base station particle accelerator, ion beam might cause radiation damage to High Stage One platform, to GEO Node and perhaps other objects.
Rockets risk explosions, and they are very expensive (typical launch easily exceeds $100M).   Space Elevator's CNT tether is a good non-rocket, launch concept, but the deployment is extremely complex also with a high price tag.  Even worse, any tether will inevitably break with huge impact to Earth's population. Thought Experiment proposes that SE adapt a much more practical "virtual tether", an augmented ion beam to propel vehicles from surface to GEO.  

CONCLUSION:  By avoiding lower atmosphere's wind and weather, a "High Stage One" launch platform might expedite launch of Beam Rider vehicle.



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