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Comment by chroem | Hacker News Reader

But with this we could kill people all over the globe in record time!

Edit: Just to be clear, this is sarcasm.

Well it is more for spying. And with advances in gigapixel digital sensors, satellites and drones, a mach 6 manned plane is probably pointless for spying in comparison.

Let's fund things that can break earth orbit and inspire the world.

Satellites have fixed orbits, which makes them relatively easy to hide from because you can figure out when they can see you.

Drones are good for spying because they're unpredictable, silent, and pretty much invisible, but their range isn't great. If you're not within range of a place where drones can be deployed, you're relatively safe from them.

A mach 6 manned plane can be anyplace, anytime. They can sit in their base in Nevada (or wherever) and be deployed to investigate anyplace in the world within a matter of hours. Drones and satellites just don't compare to that.

So, if you accept that the basic mission of these technologies is valid, then it makes sense to develop manned aircraft. It's just unfortunate that it takes so long for the technology that's developed to trickle out of the secret programs so everyone can get some benefit from it.

If the satellite imaging is good enough, it's probably cheaper to just have complete coverage. GPS was like 20 billion? a billion in ongoing costs?

If i understand correctly, a new jet is a trillion dollars.

Perhaps the imaging isn't good enough, cloud cover or whatever, but a whole bunch of satellites seems like a far simpler solution.

Or...

You could monitor sub-atomic particles(WIMPs) in real-time.

Drones can be anyplace in the world within a matter of hours too, if you keep a bunch of them on station all over the place. And while that sounds expensive, drones are so cheap (relatively) to build and operate that it's still going to be far more cost effective than a mach 6 anything.

Drones are not as cheap as you would think (, and I used to believe). Global hawks cost as much as U2s to operate, and much more to acquire;[1] predators and reapers are not cheap either, once you include the whole control system.[2]

[1] http://www.defensenews.com/article/20130624/C4ISR01/30701001... [2] http://americansecurityproject.org/blog/2012/the-us-and-its-...

This would make awesome reusable first stage for orbital launches. Provided, of course, other air launch problems could be solved.

Going mach 6 at high altitude is not as much of a boost as it seems.

Consider that orbital velocity is ~mach 25, and energy = (1/2)mv^2. Launching a space vehicle from a carrier moving mach 6 would give you (6^2)/(25^2)= 5.76% of the energy required to reach orbit.

You do get some benefit from launching at high altitude, and reducing atmospheric drag, but that does not require a high speed launch. The high speed launch adds significant danger due to aerodynamic issues, along with requiring a massive fuel expenditure, and a much heavier, more complex, and expensive carrier.

At the height of the moon mission, we spent 4.4% of our GDP trying to get to the moon. We did it, and haven't been back in 40 years. What you're saying does not work.

How can you measure the return on investment for all we learned from trying to get to the moon? From inspiring so many people to go into science.

I don't think building better war machines inspires people to go into science.

You can't measure the ROI, and honestly the ROI argument is as rhetorical and handwavy as the "TSA makes us safer" argument. It only feels somewhat plausible, but is so utterly vague and unmeasurable that there's simply no way to make it not an empty statement.

Also, I'm as anti-warmongering as everyone else here, but it's a patently false claim to say that the industry of war doesn't drive massive leaps in science and technology. Silicon Valley itself was birthed out of massive military research funding post-WW2. The Internet started as a DARPA project. The foundational technology we built on top of to get the moon was reversed engineered in large part out of deadly German V2 rockets captured during the war.

Hell, one of the biggest chief architects of the US space program was Wernher von Braun, whose rocketry expertise came out of Nazi Germany. The Russians weren't exempt either - all of their early satellite and manned mission launch vehicles were derivatives of ICBMs - Sputnik, the first satellite in orbit, launched from a R-7 ICBM.

I wish it weren't the case, but there is tons of evidence, all around the world and all throughout history, that the waging of war drives a shitload of science.

I think you missed my point. We weren't inspired enough to continue once we reached the moon. We did not continue on to Mars, and we didn't want to increase NASA's budget. Most people here weren't even born when we went to the moon.

Consider that we need to import engineers in the US because many Americans don't want to do the job.

Why, because they quit spending it?

The US spends 4-5% of its GDP on defense every year, year after year, without end.

When you fund gigantic science projects and then kill the funding as soon as they show any success, well, surprise! They stop. So don't do that.

Maybe we could drop defense spending to a mere 3% of GDP (still more, in absolute terms, than any other country in the world, and a level seen as recently as 2001) and spend the leftovers on space and other science research.

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