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Space elevator on Earth will likely never be possible without some huge unforeseen leap in materials science, this is true. However a space elevator on the moon to get manufactured materials into lunar orbit for a trip down hill may be.

A launch loop would be more feasible, according to this.

Which is why we need one of these: http://en.wikipedia.org/wiki/Launch_loop

Have a look at the economics:

For a launch loop to be economically viable it would require customers with sufficiently large payload launch requirements.

Lofstrom estimates that an initial loop costing roughly $10 billion with a 1 year payback could launch 40,000 metric tons per year, and cut launch costs to $300/kg, or for $30 billion, with a larger power generation capacity, the loop would be capable of launching 6 million metric tons per year, and given a 5 year payback period, the costs for accessing space with a launch loop could be as low as $3/kg.[ http://launchloop.com/LaunchLoop?action=AttachFile&do=view&target=isdc2002loop.pdf ]

http://www.launchloop.com/ and http://en.wikipedia.org/wiki/Launch_loop detail the Lofstrom Launch Loop. Lofstrom, an IC designer and FreeGeek.org volunteer in metro Portland, Oregon, has a system which requires no unobtainium and could be built today, without any 'suitable mountain top' with only COTS (Cheap Off The Shelf) components.

You can also use something like a Launch Loop (see http://en.wikipedia.org/wiki/Launch_loop, http://www.launchloop.com/ and http://www.keithl.com/), so the answer to your question "How fast should a streamlined package need to go if you fire it up that way?" is 14 Kilometers per second.

sounds like a problem for a http://www.launchloop.com/

"How much will it cost? I have no idea..." -quoted from page 27. http://www.launchloop.com/isdc2002loop.pdf

A rough estimate (pdf link to presentation slides, estimates towards end) puts it around $10 billion for a small system, and $30 billion for a larger one. Add on an order of magnitude to the price for government waste, and it's still pretty good. Better than the most optimistic estimates for a space elevator, and way better than rockets.

Building over an ocean (or rather, starting from an uninhabited island and extending over the ocean) isn't really a big deal. Baker Island will do as long as we can deal with the pesky environmentalists trying to save its status as a wildlife refuge.

According to this presentation

http://www.launchloop.com/isdc2002energy.pdf

32 megajoules of energy are found in 1/4 gallon of gasoline, or the sunlight falling on a square meter of Denver, Co on a sunny day. If correct, the energy requirements of these guns are far less than what the original poster has presumed them to be....

Basically, its a magnetic rail gun for launching space-craft into orbit. And in order to avoid the crushing G-forces involved, it has to be hundreds of miles long. So, while it may not be economically or politically viable, it is technically feasible. We know how to build a launch loop, as opposed to a Space Elevator, which can't be constructed with current technology.

-Sean

There are other ways to get into space without extending a strucuture beyond geosynchronous orbit. Check out launch loop and this wikipedia page.

Ya know, we could build a structure to space with todays (hell, 20+ year old) technology if we wanted. The Launch Loop concept was published 20 years ago and is viable today.

The majority of studies that remain to be done to make the Launch Loop a reality are much the same as the many studies that still need to be done to make the space elevator a reality.

Launch Loop presentation and Space Elevator presentation .

For large projects to be realized, they either have to be of decisive strategic/military value during war (Manhattan project), or they have to completely capture the hearts of the citizens that are supposed to pay for it all (Apollo Project, "before this decade is out..."). Clearly, for the Space Elevator, the latter is the case. I, for one, have not heard of Launch Loop before, and the dry PDFs and text files that are Google's #1 on the term didn't really invite me to care about it. The Space Elevator, on the other hand, has been part of the popular culture for decades, and has recently surged astronomically (no pun intended) in terms of mainstream recognition.

Just as it would have been more affordable and scientifically more valuable to gradually conquer space and ultimately the moon (i.e. with manned space stations and a launch from space etc.), it was the extreme appeal of the "moon shot", the giant leap that won the favor over the more economical approach.

Sigh. Ya know, we could build a structure to space with todays (hell, 20+ year old) technology if we wanted. The Launch Loop concept was published 20 years ago and is viable today. It costs less than a space elevator is predicted to cost and, unlike the space elevator, can be built from the ground up instead of from orbit down. So yeah, please stop saying stuff like: once we have strong carbon nanotube fibres we'll have a space elevator two weeks later. It doesn't work like that. The majority of studies that remain to be done to make the Launch Loop a reality are much the same as the many studies that still need to be done to make the space elevator a reality. Someone has got to finance those studies and unless you can get PhD students to do it on government funding that means you've got to pour money into a hole that might never fill up.

throw current launch prices for a loop

Maybe that's not the right tack either...