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Comment by ashleyn | Hacker News Reader

It's disappointing that SST died off the way it did. In the 1960s, the 747 was originally designed as a stopgap between subsonic and supersonic, which was viewed as the next inevitable step.

Unfortunately, in a hamfisted effort to study the impact of sonic booms, the air force created so many over Oklahoma City that the government lost a very large lawsuit over the damage done to nearby buildings. Regulations ensued, and that effectively stunted any efforts to minimise the sonic boom in commercial applications.

I'm hopeful this can kickstart a new effort to renew SST and scale it to where it was more cost effective than the Concorde tried to be.

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Sonic Booms wern't the only problem. It's hard to get around the cost element since jet fuel is a significant chunk of an airline ticket and SSTs are necessarily going to burn a lot more of it. Ultimately people largely chose to save the $1,000 and take the extra 3 hour penalty to their trip. Even for people willing to pay more you have to consider competition like the luxurious Emirates A380s that give you a small bedroom for the trip vs. the coach seats on the Concorde.

It's probably worthwhile to continue researching the space, but it's hard to see the economics working out--especially outside of small business jets. There just aren't that many people who care enough about extra hours that they can already travel in a fair bit of comfort if they're willing to pay for it. This is especially true if the design can't handle truly long distance travel like trans-Pacific.

Although it's not quite the same thing, I'd observe that British Airways has even cut back on its business class-only flights from London to New York. There just aren't that many people willing to pay thousands of dollars to either save a few hours or to travel in more comfort for a few hours.

The United States spent $20 billion for air conditioning during the Afghanistan and Iraq wars.

https://www.huffingtonpost.com/2011/06/21/air-conditioning-m...

Perhaps in the near term it only makes sense for business jets, but it is a step forward. It isn’t money down the drain and the research will pay future dividends.

> The United States spent $20 billion for air conditioning during the Afghanistan and Iraq wars.

What does that have to do with the discussion at hand? I am struggling to see the relevance.

> The United States spent $20 billion for air conditioning during the Afghanistan and Iraq wars.

Do you think this is some kind of luxury? Have you got any idea how hot it gets in an operations room tent in Afghanistan? And some of those tents are hospitals.

I was going to simply say that we spent $1 trillion on the Iraq War (another trillion in Afghanistan).

I was only trying to show how little the research costs in the big scheme of things.

For those curious, the Oklahoma City boom tests is explained in full here: https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests

I have hope that SpaceX BFR will break past the sonic boom problem by doing the zoomy stuff outside the sound transmitting parts of the atmosphere.

As much as I like what SpaceX are doing, I'm personally dubious about the idea of tens or hundreds of large scale ballistic rocket launches every day and their affect on the atmosphere, purely for consumer travel.

The thought of making a colander out of our ozone and ionosphere sends shudders down my spine.

They are LOX/kerosene so it's not as bad as hydrazine or something. And it's less fuel for a suborbital lob and subsequent braking burn than for LEO. And a good portion of the journey is unpowered ballistic drift.

But yeah, it probably isn't ideal for the atmosphere.

SpaceX are using methane for BFR point to point, not kerosene. Burns cleaner, and they're planning on synthesizing it eventually like they need to do for Mars.

Although I suspect that long-term, if you're synthesizing your fuel, you're better off using hydrogen instead of methane. Structural mass is generally higher if you use hydrogen, but there is a performance boost especially at higher velocities. And you avoid the inevitable energy loss from the Sabatier Reaction. And generally better for the climate than methane, particularly if you're running fuel-rich.

From a conservation of mass standpoint, synthesizing methane would be better for the climate. The stored fuel represents temporarily sequestered carbon. The exhaust, whether the engine runs rich or lean, only represents carbon that was in the atmosphere before the Sabatier reaction was run. However, the total size of the launch vehicle market renders these speculations superfluous, for now.

The problem isn't just carbon mass (i.e. CO2 in the atmosphere), but the fact that methane is a much stronger greenhouse gas than CO2 per unit carbon.

The total size of the launch market today is infinitesimal (~100 launches per year and vast majority less than a tenth the payload capacity of BFR). But BFR is being built to change that by orders of magnitude. Long-haul point-to-point transport of people means potentially hundreds of thousands to millions of flights per year. Long road to get there, though, and the primary obstacle may just be the incredible airline safety record (to make it close, you probably need to include lifetime saved by making the trips shorter).

It's not a stronger greenhouse gas than CO2 when it's sitting in a tank, and it's not a stronger greenhouse gas when it's emitted as hot, reactive exhaust into the atmosphere, where it is immediately reduced to CO2, CO, H2, H, H2O, HO, and so on.

But, like I said, premature and superfluous, even though we should still do our accounting carefully, and not rely on "OMG methane!" as the guiding principle of our thinking.

Hydrolox will always be a more efficient fuel, but it's a nightmare to store and manage, and destructive to engine components, fuel lines, storage tanks, and, well, everything it touches.

It may be tough to have a reusable hydrolox rocket that's efficient from a total cost of ownership perspective.

I think we should consider the cost benefit analysis and maybe it makes sense to mandate that boosters throttle back when transiting the ionosphere. Especially if we are going to increase launches by a factor of ten or more.

An active startup: https://boomsupersonic.com/

As long as airport transportation and security continues to be a dog and pony show, that wastes more of my time then the flight does, I'd rather fly subsonic. Hell, I'll take one tenth of the delta between the two tickets, and splurge for extra leg room and a bottle of wine to see me through the flight.

Boeing had a competing transsonic design that lost to the 787. We hit $4/gal for gas during planning and airlines were interested in operating costs. Not shaving 90 minutes off an intercontinental flight.

Poor Oklahoma just can't catch a break. First supersonic planes, now fracking destroying its infrastructure.

http://www.businessinsider.com/earthquakes-fracking-oklahoma...

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