[Aeronaut]

We (fusion, let alone aneutronic) weren’t specifically included because the organizers are looking for new frontiers in the existing paradigm so they can develop a new paradigm. I’m sure Eric and Aaron will be asked to keynote the next one.

[Aeronaut]

The stuff I was reading several years ago was based on a fairly constant 120 MPH velocity in both directions, powered by laser(s). That’s plenty fast enough for tourists only going around 62 miles to get their astronaut wings and join the zero-g club. The vast majority of the 69,000 mile tether would be used as spaceports to various destinations in both launch and recovery modes.

[Aeronaut]

jamesr wrote:

I just read on Wikipedia:

The physical characteristics of decaborane(14) resemble those of the organic compounds, such as naphthalene and anthracene, in that it can be sublimed under vacuum at moderate temperatures. Sublimation is the common method of purification.

So as we are working in a vacuum, possibly heating isn’t required at all.

I think at the 10-40torr or so pressure FoFu will be operating you’ll need to warm it slightly to sublimate it. You also want the rest of the chamber warmed, as it would condense on room temperature surfaces & leave residues everywhere.

For the first shot in a series, since the cooling system can set the chamber wall temp wherever it works best for the fill pressure.

[Aeronaut]

Does it have to send to multiple locations?

[Aeronaut]

Brian H wrote:

…

I’d like to see at least one variation of a tractor beam. One pushes against mass, the other pulls toward a large mass.

I’d like to chide you for wanting “spooky action at a distance”, were it not that that’s actually a good description of every field and force in physics. Phagh! :cheese: :grrr:

I’d also like to add a transporter to my wish list. Flip Phone’s already accomplished.

[Aeronaut]

vansig wrote:

Actually I even wonder: what is the advantage of using a tether? Basically the only problem it addresses is avoiding reaction mass.

reaction mass is the single largest problem in rocketry!

it’s time for new physics; i want that reactionless thruster now, please. there may be no other way to get to the stars

The tether also eliminates the need for multi-G force liftoff and re-entries, which opens space tourism to almost anybody. Just as reaction mass has geometric multipliers, minimizing it has geometric dividers. The less mass of any type that you need, the better off you are.

I’d like to see at least one variation of a tractor beam. One pushes against mass, the other pulls toward a large mass.

[Aeronaut]

The quick trip is to the “off-shore” activities that will pop up around 60 miles. That’s where I expect the first tourist stops to be, followed by commercial access fees to use any or all of the tether as a launch system. The less reaction mass that you have to leave the ground and or orbit with, the smaller, lighter, and cheaper your launch vehicle gets. This also pays dividends in smaller thrusters and shorter burns, which also contribute to lower reaction mass requirements.

The tether is easy to “understand”, which makes it easier to sell than a pendulum or a balloon (why hasn’t somebody done this before?). The tether concept also eliminates the need for heat shielding and a retro-burn to re-enter the atmosphere. While this all will probably seem quaint to an “enlightened” reader in less than 50 years, its about the best we can do right now and is still light years ahead of what most people think is possible.

[Aeronaut]

Breakable wrote: Another major issue I see with Space Elevator besides the tether material is its throughput. What is the planned speed and the amount of payload it can deliver?
If we say that it can deliver a few tons of payload per day,
then the infrastructure costs (especially with alternative cheaper-than-currently methods) will be a very long term investment
and might not even pay for itself.

My understanding is moving 30 ton loads (probably gross earth weight) at 120 mph most of the trip, for a 30 to 45 minute trip each way. Say 720 gross tons per day for a guesstimate…

[Aeronaut]

Tulse wrote: Tri-Alpha Energy receives $50 million in funding. Given their previous round of VC funding, this puts the whole project close to $100 million so far, without any publicly reported results.

And apparently with none of the original investors ponying up further capital. We have 2 rounds from NASA’s JPL and 2 more from the Abbell Foundation. PolyWell has who knows how many rounds of US Navy funding under its belt.

[Aeronaut]

My understanding is that we’re validating McNally’s 1975 observation that bremstrahlung can be reduced by raising field strength, which has a lot to do with why high input currents are critical to reaching unity. This was mentioned in the GoogleTalks and in the patent, if I remember correctly. At this point it’s a theory which seems to be proving out experimentally, but I may be wrong on that- the relative motion of ions and electrons are beyond my direct understanding of the process.

[Aeronaut]

The tether needs to be at least 100 times stronger than steel (I know this lacks precision in defining which characteristics- sorry) and apparently the carbon nanotube weave can or will soon be able to do that, according to the article.

One issue that hasn’t been pointed out, since nobody details their SWAGs (Rematog’s term Silly Wild Asked Guess), is the cost of the tether itself and the various overhead involved in replacing it on a regular basis. I’m guessing that the real budget-busters are freight aboard the chemical rocket required to loft the first tether, along with the structures at both ends and the incremental research programs. Replacing the tether every year or few might turn out to be cheap insurance.

[Aeronaut]

I have to disagree, Aaron, based on what actually had to happen before Parliament would listen seriously to what Churchill was telling them about Hitler’s book Mein Kampf. Sure hope I’m wrong, but America’s lost it’s edge because it has no effective leadership in business or politics. Only reactionary thinking in those places, and a general public that’s been taught to expect Washington to solve all of their problems.

[Aeronaut]

I was wondering if I’d missed a jargon term. Been a while since I’d actually looked into how an elevator might be built, deployed, and operated, and I never did see anything reasonably current.

If aerogel’s a good electrical conductor, a mag field effect might keep it up.

[Aeronaut]

That’s great if they pursue it to the degree that building a Mather and a Fillipov lab suggest. It gives them much needed credibility on the world stage and lends more credence to aneutronic fusion.

Interesting word for confinement. Sounds like ministry of information copy rather than ministry of science writing.

[Aeronaut]

What does SLT stand for, Brian? The aerogel tube sounds like a great start. Especially if they can deflect most junk.

Breakable, I agree that the goal is to reduce the cost of getting a specified amount of freight to and from orbit- which can and should be interpreted as an orbit relative to at least our sun, to enable the system to initiate ballistic transfer orbits. But until a ship’s drive can eliminate the need for rockets and heat shields, I doubt they’ll be really useful for anything other than really heavy lifting and or 8 minute access to orbit due to the enormous mass handicaps that they leave the drawing board with.

[Author]

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