I think the more important step is that SpaceX has broken the "credibility ceiling" for private space ventures. When they started competing for the CRS and Commercial Crew contracts a number of important voices in Congress were amused but not convinced, and when it became clear they were going to deliver something on their promise they actively campaigned against such "risky" ventures, and trusting someone other than NASA & the original space contracting collective (Lockheed, Boeing, Aerojet, Etc.) with the ability to actually launch. There were the incredibly bogus "export licenses" which were code for regulating launches, there were outsized estimates of risks, amazing requirements for "proof" of competency. But now we're on the other side of that cloud and SpaceX, Orbital, and perhaps soon Blue Origin will be part of the "club". Pretty exciting times for the new kids, scary as heck for the previous club members (like ULA).
I also remember reading or hearing one of the original astronauts being ideologically resistant to private companies rather than civic supported programs being at the forefront of space exploration. However, here is the closest I can find, from Buzz Aldrin in a Reddit iAMA:
That's interesting, but a distinctly different topic. In the 60 Minutes show referenced in my Quora link, which is where I got the idea in the first place, Armstrong and Cernan were portrayed as being against private development in the manner of SpaceX because the profit motive would undermine safety.
> In fact, if Earth were 50 percent larger, with a correspondingly stronger gravitational pull, no form of chemical propulsion would contain enough energy to launch a spacecraft into orbit.
This is quite a strange statement. Not even with multiple stages? Not even Saturn-V would be able to lift a cubesat - with necessary extra stages? I'd like to see numbers which support that.
As I understand it, it's a practicality issue: with enough extra stages you can always escape, but the payload size rapidly approaches zero. (See: http://space.stackexchange.com/a/5383)
The size, complexity, and costs of extra stages make it impossible once you add in the actual real-world constraints. As said in Terr_'s link: "Rockets at 85% propellant and 15% structure and payload are on the extreme edge of our engineering ability to even fabricate (and to pay for!). They require constant engineering to keep flying."
Thank you for your reply - and thank all the others who replied.
This is a link on a NASA website :) and that organization is known to err in questions related to space. Seriously, guys - Don Pettit wrote it for general audience, and skimming the article I spotted this -
> Hydrogen-oxygen is the most energetic chemical reaction known for use in a human rated rocket. Chemistry is unable to give us any more.
> The highest measured Isp ever achieved with chemical propellants was with LH2/LF2/LLi (yes, liquid lithium), at 542s in vacuum.
Next, 15% structure certainly doesn't apply to some first stages - particularly recent Falcons from SpaceX.
The point which I was trying to make is I doubt that big of a difference. Sure, it's pretty hard to get to orbit from, say, Jupiter-like planet. However orbital speed for a planet with constant density is linear by the planet radius, and to get to New Horizons' ~16 km/s delta V as orbital speed the Earth would have to be 2 times bigger - 8 times heavier. And New Horizon's ain't cubesat either.
And, on top of that, we still have other readily available tricks up our sleeve. So I think even with rather large variations of Earth size we'd get in time to the stars.
In theory you could always add more, ever larger stages to the bottom to keep increasing delta-V. But in practice there's a limit to how big we can make something. Weight increases as l^3 but strength as l^2 so at some point you just won't be able to create a large enough stage with existing materials.
How about putting two of the same stages alongside? No difference in mass ratio whatsoever.
Besides, we aren't actually at the limit of even modern materials. Rockets were built decades ago - and comparatively slowly evolved ever since. SpaceX demonstrates the hidden opportunities.
Staging isn't magic. It just lets you get rid of some dead weight. The fundamental problem is that the "future" fuel you need to carry with you gets too heavy to lift.
Being in the midst of all of this, I can vouch for the palpable excitement within the industry: at least if you stay away from talking to traditional prime contractors. There's a real sense that disruption is right around the corner. The biggest problem is that there have been no significant exits to prove investors right. This makes it difficult to raise capital.
Also, traditionally, external capital has sought out downstream opportunities. We've been focussing on upstream tech and it's much harder to prove the case given the long time horizon.
I've seen some incredible applications being pitched, but I think the real test will be whether they are able to generate significant exits. I, for one, hope that the next five years spells a period of immense productivity in the sector, generating profitability all along the value chain. If we're able to ride that wave, I think that there are many more applications that will pop up that make use of space infrastructure.
A lot of applications are much closer to home. For instance, I've seen a few teams pitch the idea of building a robust, small-satellite network to serve as a platform for Machine-2-Machine messaging. I think enabling the global IoT industry is really going to unleash some spectacular applications. Internet everywhere is of course a popular idea that's being worked on. I particularly like the low-data rate, low monthly charge model that I've seen pitched. Seen teams pitch internet anywhere for as low as a couple of bucks a month.
I had expected more due-diligence before publishing the article by HBS - sadly they have included a promising piece on Escape Dynamics without bothering to check that it has already closed down! http://escapedynamics.com/
I don't think so. It seems like it was not because of lack of technology that failed a startup like escape dynamics but rather unwilling investors who were concerned about near term financial gains. Also, ground based for microwave driven IMHO is not the way to go if you are looking for reduced cost per kg per launch. No offense to the team, but they should be looking at orbital based techniques for similar power transfers - relyin on reduced atmospheric interference and much stronger power generation from direct sunlight.
