If they can get a viable Scramjet operational,...?

Wouldn't it be possible to build a new type of space shuttle that could simply coast into orbit on interia alone if it accelerated to the desired Mach speed for its mass to attain a sub-orbital trajectory?

Then we can finally stop sending our astronauts up on potential bombs waiting for an opportunity to go boom.

Also the potential for a commercial civil aerospace program could be acheivable a lot sooner. If there are entrepenures out there with enough moxie to make it happen.

That's the "ultimate shuttle"--and you're exactly right. Getting there is likely to take quite a long time, though. Currently, the best test vehicles (Australia and th eUS) have managed about Mach 7-orbital speed takes Mach 25.

But--that's not as bad as it sounds. Most of the fuel a rocket like the shuttle uses is at theat lower speed. For example, the current Shuttle's solid rocket boosters are used up at about Mach 6--and the Main Engines have been firing as well, so part of the fuel in the External tank has been used as well. Thats about 60% of the entire liftoff weight.

Also--there are new technologies that can eliminate much of the risk of using rockets. So--what we're likely to see (say in the late 2020s or 2030s) is a descendant of the Shuttle that uses a "hybrid" propulsion system--scramjets and then rocket power for the final phase of aceleratioon into orbit.

Over time, of course, that will cange--eventually we will see that "ultimate" shuttle--with all the benefits you pointed out.

sorry, but the entrapenuers are WAY ahead of you.

Scaled Composites created a ship named spaceship one.
It was the first privately funded company to put 3 humans into orbit and carry a payload.

http://www.scaled.com/projects/tierone/

here's a video of the ship
http://www.youtube.com/watch?v=FNXahIoXM...

once they won the X price challange, virgin airlines made a deal with them to design a new ship for the general public to fly daily (for 200,000$ for a ride though still cheap)

its ready and tested, I believe some fine tuning is in process and will be done next year I think.

http://www.virgingalactic.com/flash.html

oh, and some people put 8 billion dollars together to build a hotel in space.
$4 million for you to train for space and spa about and snorkle on a tropical island for 18 weeks, then spend 3 night in orbit.
watching 15 sunsets in 24 hours.
pretty cool, but won't be ready till 2012
http://www.galacticsuite.com/

google is awarding the first private company 30 million dollars for the first to send a ship out into space and to the moon, drop a robotic probe and recieve data from it
http://tech.blorge.com/Structure:%20/200...

can I at least have a thumbs up now

Even scram jets have to have a lot of the same nasty fuel as rockets. Their advantage is that they can get oxygen from a much thinner (higher) atmosphere and get a lot closer to space than conventional jets do. Once in space they would have to have regular rockets since there is NO oxygen is space.

First of all, Spaceship One was able to get into space but not into a stable orbit. It is only capable of suborbital flight. It is still a long way away from acheiving orbital flight. SpaceX is trying to come up with a low cost launcher (still in the millions per launch) but it is so far 0 for 2.

Second of all, a Scramjet still need air to operate. For launch, there is a very good reason why they want to go straight up. They want to get through the atmosphere as soon as possible because the amount of friction is too great and it would be very inefficient to propel a rocket inside the atmosphere. If you are to acheive orbital velocity inside the atmosphere you would need some pretty exotic metal to withstand the heat generated by the friction. Besides, why would you think scramjets are any safer than our current launch vehicles? They still need to carry highly combustible fuel, and lots of it if you want to lift anything heavy into space.