Isn't that Thunderbird 3...?

No doubt most have seen these already, but a reminder that rockets and getting to space are difficult (if you've played Kerbal Space Program, you'll especially know this!).

The recent Russian Proton M explosion:

And the sound on this amateur video is thunderous.

I still don't get why we launch rockets from the ground, it seems horribly inefficient. We have planes that can basically reach the edge of space, why not just fire a vastly smaller rocket engine once you're already up there to get the final push (kinda like what virgin galactic is doing)? Seems way cheaper and easier and I'm surprised more space programs aren't trying it.

Oh I think I know this one 

Attaining an orbit is about speed, rather than height. It doesn't matter how high you are in the atmosphere or even above it when you start, your craft still needs to achieve a velocity of about 7 km/s or 15,000 mph to achieve an orbit around earth. Otherwise you just fall back down again. That's a lot of thrust, and if you're launching a lot of weight (which is usually mostly fuel), it's actually easier to start from zero speed on the ground rather than half way up at X speed, where you'd need a very powerful engine to take off and get you going, as it were. The current airspeed record of a jet is the SR-71 blackbird, and that's a 'mere' 2000 mph (according to wiki mind) without carrying something else like a payload. That's a big difference in speed which rockets then need to accomplish, which require substantial fuel, weighing down the plane further. Unfortunately, the business of getting into space is this awful race between engine and weight and the ratio between fuel used and actual payload put in orbit is almost sickening. Unfortunately, our currently most efficient method of thrust needs all that fuel weight to function, as rockets work on the principle of ejecting all that mass to provide acceleration (reaction thrust). It's all horribly inefficient but it's all we have for the moment and in the grand scheme, the 2,000 mph speed boost you'd get from a plane isn't worth it.

Remember, SpaceShipTwo (Virgin's plane) is only suborbital, so it's never attaining the necessary speed to go into orbit (wiki says it's top speed is 4000 km/h) and it's also reasonably lightweight so it doesn't need to hitch a ride on a monster to get into the air for the first leg. The speed difference in this case does make it worthwhile.

I think at the start of the thread I posted about the Skylon spaceplane, which is still in development and involves a special hybrid engine which gets the plane up to around Mach 6 and then starts burning like a rocket. The idea of a SSTO spaceplane has been around for decades, and no-one has really figured out how to make it work. The Skylon people are closest, but it's still years away with many more hours of testing and engineering. It is, in my view, the future and could dramatically change the way we do space.

edit - DAMN YOU TREY!!

Last edited by redxavier (2013-07-03 20:46:19)

They keep trying air launches, but the plane part basically just replaces the disposable first stage, and in the end it's more complicated and expensive than just starting with rockets on the ground. The best you can hope for is a reusable rocket first stage, like Space X is trying to build.

If anyone DOES manage to do it, it will probably be the military, as the ability to put something small into orbit without a large, easy to detect ground launch might have uses worth the price. Hell, the small unmanned mini-shuttle they're playing with might be air launched at some point.

It already is a thing, but the keyword is smaller payloads.    For example there's the Pegasus rocket, with a max payload of about 1000 lbs.  Enough for a small satellite, not nearly enough for a passenger vehicle.

Anything much bigger than that and the orbital vehicle gets so fuel-heavy that no plane could carry it.    Or, to look at it another way - a 747 can obviously carry a Space Shuttle... but it can't also carry the massive propellant load required to get the Space Shuttle into orbit.

Oh wow, see, I had no clue this was going on. Pretty damn cool.

I remember similar questions being asked during the 80s, about the Space Shuttle: "If it can land like a normal plane, why can't it take off like one?" My (awful) 6th grade science fair project said the answer was "Earth's gravity"—I drew pictures about how it takes more "rockets" to shoot the shuttle out there than it does to bring it home. I built an ugly papier-mache replica of Discovery, and the twin rocket boosters were PVC pipe. None of it to scale.

Some more guys to root for:
http://www.planetaryresources.com/2013/ … telescope/

Looks legit to me, granted I'm no rocket surgeon.

I'm most interested in the permanent cloud city or cities that this project requires, and the economy that will evolve to support it/them.

Last edited by drewjmore (2013-07-04 14:33:12)

It looks less impressive in video 

I seem to have missed this earlier, but Inspiration Mars sounds like a very real and feasible project. It involves a Mars flyby (within 100 miles of the surface I believe), with a launch in January 2018, with a married couple on board. Similar sort of thing as Apollo 8. These two humans would be the first of our kind to ever leave our little neighbourhood!

Video animation:

A conference with more details:

Last edited by redxavier (2013-07-05 14:56:28)

A continuous strand of any material currently known or expected for use in a space elevator is literally unobtainium. I did the math on it once, and I should either find or re-do the spreadsheet, but the crux is that you need at least 20,000 MILES of whatever you use, and it has to carry it's own weight plus a load. Assuming you use the highest strength steel for the cable, it has to be something like a mile thick near the geosync station just to carry it's own weight.

Which is to say, I think a train of balloons (an idea I've been quietly discussing with a few of my most non-judgemental friends) is the solution to the problem of getting to nearspace. If you build 1000 airships and tether them for guidance, every cable between them is well within it's working load limit...Assuming fair winds. For going higher from there, I've seen plans for lower orbit tethers that are dynamic: they whirl around and the ends swoop down into the stratosphere to grab payload and sling it into higher orbit.

On the other hand JPA is not tethering their Dark Sky Station, it will float free as far as I can discern.

You know, my only real argument against the idea would be the inevitable muzak version of the theme from 2001. Other than that, I'd love to ride a frickin' space elevator.

I can almost hear the first stuck-in-a-space-elevator movie being pitched by Brent Ratner...