How do you propose building the tower when it is 2 magnitudes taller than anything ever built?
The "when it is 2 magnitudes taller than anything ever built?" isn't relevant,
Quote from: Jim on 12/05/2011 04:51 pmHow do you propose building the tower when it is 2 magnitudes taller than anything ever built?That's a good question. Much, much research and development is required for this to be feasible. For a second generation tower, the tower will be approximately 150 km tall and support an estimated 3,100 metric tons. The tower will precess since it will be located anywhere from 0o to 50o north latitude. (What aerospace company wants to operate out of the north pole?) IMO, a tower under tension is the only possibility. Several authors have theorized on the possibility of tall support towers (references below). The analysis for the support tower relies heavily on the work presented in "Feasibility of a 20 km Free-Standing Inflatable Space Tower" by R. K. Seth, B. M. Quine, and Z. H. Zhu. For the case of a second generation system, the material of choice is a carbon nanotube material with a working tensile strength of 25 GPa. The tower would be filled with hydrogen from 20 km to 150 km and helium from 0 km to 20 km. The top 10 km of tower will have to be pressurized to 4.8 x 105 N/m2. The pressure will increase as more mass is added to the tower. The initial design of the tower is in 10 km increments for the hydrogen fill and 5 km increments for the helium fill. Guy wires will be attached to retard the precession. Unfortunately, due to the elasticity of the CNT cable, the tower will sway an estimated 10 km southward with a period of 4.4 minutes. Strong stomachs are advised.ReferencesFisher, J.F., 2011, Space Track Launch System - Tower, www.fisherspacesystems.comSmitherman Jr., D.V., 2000, Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium, MASA/CP-2000-210429Seth, R.K., Quine, B.M., and Zhu, Z.H., 2009, Feasibility of 20 Km Free-Standing Inflatable Space Tower, JBIS, Vol. 62. pp. 342-353, 2009Bolonkin, A.A., 2003, Optimal Inflatable Space Towers with 3-100 km Height, JBIS, Vol. 56, pp. 87-97, 2003
Quote from: Jim on 12/05/2011 04:51 pmHow do you propose building the tower when it is 2 magnitudes taller than anything ever built?The "when it is 2 magnitudes taller than anything ever built?" isn't relevant, like all the creative alternative ideas it comes down to: Is it possible, what's the cost, and who's going to foot the bill?This idea is the opposite of HASTOL, which would use a rocket first stage with a tether second stage, I wonder if combining the two to get a tether to tether system would be possible.
This idea is the opposite of HASTOL, which would use a rocket first stage with a tether second stage, I wonder if combining the two to get a tether to tether system would be possible.
Quote: "And how are the huge costs of this infrastructure going to make spacelaunch cheaper? " A detailed cost analysis has not been done. The first task is to determine if the STLS is technically feasible. As I have said in a previous post, I am a physicist not an engineer. I have had no technical review of this concept from my peers. This forum is the concepts debut.
But to your "basic" question of the concepts technical feasiblity; of course it's "feasible" and could "technically" be done. I've actually seen this same idea several times before though your suggestion of counter-weights and launching from the mid-point of the teather is an interesting variant that mitagates some of the difficulties with earlier suggestions, so further work is certainly useful.
6 metric tonnes (@13,227lbs) per day to orbit far exceeds current demand and one thing that many advocates of space launch concepts don't seem to understand is that you MUST be able to address CURRENT needs in order to build UP future capacity. I've said it before and I will continue to point out that Space Colonization nor large scale "use" of space are NOT currently a paradigm for any government space program, and they make up a major portion of the payload market. The OTHER percentage of the market is a commercial space utilization business who have evolved to launch large payloads into specific orbits rarely and with little or no need or incentive to subsidies over-capcity or expanded capacity for space launch.
My definition of future needs is space based solar power satellites in geostationary orbit, mining helium 3 on the moon, prospecting and mining strategic materials on near earth asteroids and in the asteroid belt, and yes, large scale colonization to support the activities.
Quote from: Jerry Fisher on 12/11/2011 08:59 pm My definition of future needs is space based solar power satellites in geostationary orbit, mining helium 3 on the moon, prospecting and mining strategic materials on near earth asteroids and in the asteroid belt, and yes, large scale colonization to support the activities.None of which may be technically viable or even commercially viable.
Have a look at this... http://www.infoblog.us/2010/12/nasa-adds-turbojets-and-rockets-to-its.html
I could go on about space colonization but I'm getting writers cramp. Google it yourself and you will find that you are in the minority concerning your comment on technical and commercial viability. There is a great many opportunities in space. Getting there is the problem and that is why I'm working on the Space Track Launch System.
how about this:http://electrictakeoff.com/