COOKED? The Realities of Tourist Flights on Space Elevators

"Good morning, I am Donia your senior flight coordinator and I welcome you to SpaceEl Flight 200 I need your complete attention as I go over with you the passenger requirements of this flight."

"Please make certain that your ascent couches are in their in-flight position. Press the green lever on the right armrest to make that adjustment. Now, also make sure that your restraint harness is fastened securely. If you are having difficulty please raise you hand and one of my assistants will come to you."

"We will be ascending at the rate of 200 miles per hour for the first hour, and then we will cut over to our rapid acceleration mode. You must be in your ascent couch and completely strapped in before we begin rapid acceleration."

"The rapid acceleration mode makes sure that we pass safely through the two radiation zones on our way to the space port. In order to do this we will be using our special VASIMR propulsion units to increase our ascent rate to 18000 miles per hour. We will do this gradually over the next half hour during which time you will experience an increase in G forces up to 5gs, however they will stabilize at 3.5gs for the remainder of our ascent. The total duration of the remainder of our flight to the spaceport is 5.5 hours."

"If you have any questions, please raise you hand. We will be departing in 15 minutes. Enjoy your trip and thank you for traveling with SpaceEl Systems."
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The above monologue is quite unbelievable, but considering the special location requirements of space elevators and the presence of intense radiation hazards from the Van Allen belts, the passenger preparations would seem realistic. Why?

First, although a serious study has been made of alternative locations, the best and most efficient and safe launch location for space elevators is at the Earths' equator. This permits the most accurate positioning of the space elevator tether and its links to its Earth-base and space anchors. Unfortunately, an equator site exposes space elevators to the most intense and thickest regions of the Van Allen radiation belts, as shown in the image above.

This is an absolutely life threatening hazard that will essentially cook the passengers of SpaceEl flight 200 unless they can be completely shielded or can pass through the radiation zones fast enough to reduce any life-endangering exposures.  In our fictional flight cited above we opt for a fast ascent through the zones.  Reading the description above makes me wonder if (a) most passengers are capable of withstanding the anticipated G forces, and (b) if any passenger bodily functions will allow them to remain strapped to their couches for a 5.5 hour period without relief.  I doubt it, or if they do it will be most likely very uncomfortable for them. The 5.5 hour duration is based upon the spaceport end of the elevator being at just over 99,000 miles above the Earth;s surface.

Another consideration is the use of VASIMR type propulsion units to speed up the ascent of the elevator.  First can the tether take the strain of such an ascent. Secondly, VASIMR propulsion units are, at this point, still in the R&D stage, and it is not certain that they would provide the needed acceleration and if so that they could meet the weight and size requirements of a space elevator.  These are all vital questions and the answers may prove to be NO!.

So, should we just chuck the idea of space elevators and move on to something else or stay with HLV systems to fling us off planet Earth?  I personally think we should NOT give up on this technology, and I think several breakthroughs will come.  Two key ones, will be effective, and lightweight radiation shielding that will allow the elevator to progress at its stately 200 miles/hour all the way to its spaceport, and the other will be an elevator propulsion system that, along with rad shields, could still move the elevator through the rad zone at a faster clip.  This latter innovation involving the development of lightweight rad shields coupled with increase ascent propulsion and speeds could solve the problem.  In this case, G forces might still be a little bit higher that Earth gravity, but less than the disabling 3.5 Gs.

Lastly, the spaceport concept served by space elevators from Earth and spacecraft that never have to exit or re-enter Earth opens the entire process of space exploration into a highly functional, potentially profitable and absolutely dynamic and thrilling prospect. This is the setting, in my mind, of a truly operational space society.  I am betting some of you, younger than me, will see it come to pass.  GOING UP!

CREDITS: The image of the Van Allen belts is courtesy of both NASA and SunTrek Adventures