Heinlein’s work is characterized by ordinary people cobbling together ordinary resources to do extraordinary things–like go to the moon. In Rocket Ship Galileo, three high school students and a nuclear physicist build a moon ship just because they can. It must have seemed possible in 1947, when that book came out. Then in the 1960s, NASA convinced everyone that only massive government programs could send people into space, and stories about people building spaceships in their back yards went by the wayside.
Now, finally, in the 21st century, science fact has caught up with the science fiction of the 1940s and 1950s. Private citizens are now building space ships for real, in large part because the winning of the Ansari X PRIZE proved it was possible.
The sad thing is that it could have been done much earlier, at least from a technological standpoint. It has been our own attitudes and policies holding us back.
My contribution to the NPRM (which the vendors themselves can’t say):
The 30 expected fatalities of the uninvolved public per million flights standard is too stringent. If six families drive from Austin to Las Cruces round trip across half Texas to go to the Spaceport to watch the dads all take a flight together, together they will expect incur 150 deaths per million flights in auto accidents.
Jon Goff says that we need to step up to the plate and comment on the latest NPRM from FAA-AST on experimental rocket licenses. Well, we don’t need moonbat comments, and it’s possible that the proposed rules are sufficiently reasonable that there is no need for further input from the industry (presumably there was a lot of industry input into their drafting). But there are just a few days left, so go read them, and comment, or forever hold your peace.
That’s how long it’s been since Kennedy’s speech in which he committed the nation to send men to the moon, and return them safely to earth, before the decade was out. A little over eight years later, the job was accomplished, with a dozen men walking on the moon over a period of three and a half years. It’s been over a third of a century since the last footprints were made.
Well, the vehicle isn’t shrinking–it’s growing, actually. But it’s SDLVness is definitely shrinking, as former astronaut Tom Jones points out:
Although it was plagued by development problems in the 1970s, the SSME has amassed more than a million seconds (more than eleven days) of reliable run time during the shuttle
…the government’s total investment in the two rockets has grown from an estimated $17 billion to more than $32 billion since its inception.
It makes one cry, when considering what we could have had instead, if a small fraction of that money been applied to actual cost reductions and reliability improvements (e.g., by putting it up as a market for delivery of water to orbit, or a prize for ten consecutive successful launches). I doubt if any of the cost-per-launch quotes for either Delta or Atlas include amortization of that outrageous welfare program. And now, having wasted all that money, they want to shut down one of them, losing the resiliency that was one of the supposed features of the program.
At least NASA is starting to come to its senses, as the once “Shuttle-derived” heavy lifter slowly morphs into an EELV-derived one, with the RS-68s, so perhaps the investment won’t be for (almost) naught.
…the government’s total investment in the two rockets has grown from an estimated $17 billion to more than $32 billion since its inception.
It makes one cry, when considering what we could have had instead, if a small fraction of that money been applied to actual cost reductions and reliability improvements (e.g., by putting it up as a market for delivery of water to orbit, or a prize for ten consecutive successful launches). I doubt if any of the cost-per-launch quotes for either Delta or Atlas include amortization of that outrageous welfare program. And now, having wasted all that money, they want to shut down one of them, losing the resiliency that was one of the supposed features of the program.
At least NASA is starting to come to its senses, as the once “Shuttle-derived” heavy lifter slowly morphs into an EELV-derived one, with the RS-68s, so perhaps the investment won’t be for (almost) naught.
…the government’s total investment in the two rockets has grown from an estimated $17 billion to more than $32 billion since its inception.
It makes one cry, when considering what we could have had instead, if a small fraction of that money been applied to actual cost reductions and reliability improvements (e.g., by putting it up as a market for delivery of water to orbit, or a prize for ten consecutive successful launches). I doubt if any of the cost-per-launch quotes for either Delta or Atlas include amortization of that outrageous welfare program. And now, having wasted all that money, they want to shut down one of them, losing the resiliency that was one of the supposed features of the program.
At least NASA is starting to come to its senses, as the once “Shuttle-derived” heavy lifter slowly morphs into an EELV-derived one, with the RS-68s, so perhaps the investment won’t be for (almost) naught.
Laboratory tests have shown that individual nanotubes can withstand an average of about 100 GPa, an unusual strength that comes courtesy of their crystalline structure. But if a nanotube is missing just one carbon atom, this can reduce its strength by as much as 30%. And a bulk material made from such tubes is even weaker. Most fibres made from nanotubes have so far had a strength much lower than 1 GPa.
Recent measurements of high-quality nanotubes have found them to be missing one carbon atom out of every 1012 bonds; that’s about one defect over 4 micrometres of nanotube length1. Defects of two or more missing atoms are much more rare, but Pugno points out that on the scale of the space elevator they become statistically probable.
Using a mathematical model that he has devised himself, and which has been tested by predicting the strength of materials such as nano-crystalline diamond, Pugno calculates that large defects will unavoidably bring a cable’s strength below about 30 GPa. His paper has been posted to arXiv2, and will appear in the July edition of the Journal of Physics: Condensed Matter.
Pugno adds that even if flawless nanotubes could be made for the space elevator, damage from micrometeorites and even erosion by oxygen atoms would render them weak. So can a space elevator be made? “With the technology available today? Never,” he says.
This seems like kind of an oxymoronic statement, because “never” implies the technology available any time, not just today. I would think that devices that continuously repaired redundant cables at a molecular level could solve this problem, though they’re not “technology available today.” In any event, I remain an agnostic.