The “skipping” approach works, requiring less delta-V than a true ballistic trajectory, and goes back to the Saenger antipodal bomber of WWII. With a gravity profile similar to that of the “Vomit Comet,” I wouldn’t enjoy the ride. Packages, maybe.

The idea is not to get too complicated. Space launchers work best when you get out of the atmosphere as soon as possible, and stay out of it as much as you can. No drag, no heating, and rocket engines operate at their highest expansion ratios.

Hypersonic spaceplanes that ride at high Mach numbers through the atmosphere may save propellant, but propellant costs are about the tiniest proportion of a launch cost, and the challenges of high-speed long-term atmospheric flight resemble the challenges of making a submarine that can go 400 miles per hour.

As you already know, there are more than a few hypersonic aircraft concepts out there. There are so many, that it’s a little confusing keeping track of which does what, and where it, or the other is going.

Some have become technology demonstrators and materials test platforms, but the one that (to me) seemed to hold the most promise, was/is Hypersoar

It’s the one that repeatedly pops in and out of the atmosphere, skipping 280 miles a pop.

“On Paper” the benefits are huge, and while it would not make the best passenger experience, (unless you like roller coasters) it would be a game changer in terms of cargo, global strike, and even satellite launch.

Your thoughts?

(If I’ve asked you this before, (and I may have) please forgive)

Without government support, (airports, regulation, standards, safety and maintenance requirements to aid consumer acceptance, navigational aids, training standards, etc), the airline industry would never have picked up as quickly as it did. By the time the jet liner came along (also at least partially dependent on defense spending) the entire ground infrastructure for the airline industry was already well in place.

This is the role government could play with space exploration.

Aircraft range and speed increased drastically. This is happening even now. I am still impressed by the fact that my flight from San Francisco to London was non-stop.

Pretty much the same thing happened with the zeppelins.

On the other hand, transcontinental suborbital space flight will never replace normal long-haul passenger and cargo aircraft. Costs, and the problems of scaling to large sizes will keep it small and expensive.

Of course, I may end up eating my words someday…

The idea was the big sea planes would not need expensive airports, they could land at existing seaports and harbors, take advantage of existing customs and tourist facilities, and passengers could transfer to existing rail or local air transport which already had terminals at important seaports to continue their journeys. And they could compete directly with ocean liners on time and cost.

The technology was already in place and tested, and service was initiated on several routes, but the idea never caught on commercially.

Like a lot of technology, it was a toy for engineers with too much government money to burn, primarily made for purposes of national prestige and status for the rich. What commercial aviation really needs is not more speed, but better fuel economy, larger cargo capacity, lower maintenance/operating costs, and the ability to operate off shorter runways. And while they’re at it, they could work on the traffic jams and security hassles at the airports. When you have to show up two hours early for a one hour flight, faster planes are not the answer.

Even for military purposes, ever-higher speeds don’t necessarily lead to a payoff. The 1960s B-58 bomber still holds several speed records, but they still didn’t keep it from becoming obsolete as a weapons system for a variety of other reasons. OTOH, the venerable 1950s low-tech, subsonic B-52 is still an important part of our defense capability.

All the fast stuff is happening outside the atmosphere. No long-term heating and drag issues, no sonic booms. Then re-entry and a normal subsonic approach to the destination (like the Shuttle, except the landing wouldn’t be “dead stick.”)

The trick is, unlike the little “up-down” space hops of Virgin Galactic, a true other-side-of-the-world hop takes almost as much delta-v as getting to orbit.

Now, that’s fast travel. Packages, too.

The reason I’ve always likes spaceplane concepts is that it can give you the option for transcontinental flights. Sure you could do it with a vertical lander, but you really want to use conventional airports.