DescentBB

Whilst reading up on the scram jet I came across this little tidbit:

"A Nasa programme to build a larger scramjet vehicle, the X-43C, has been cancelled amid the drive to produce a vehicle capable of returning to the Moon and journeying to Mars in order to fulfil President Bush's vision for space exploration."

While hearing that the president wanted to get back to the moon and beyond, I hadn't heard much about what steps were being taken to do so. Have any of you?
(expects Mobius to post dissertation complete with drawings and scale models )

$#%@!

i'm more concerned that the scramjet program was canceled. that was really going places.

woody you'd probabaly know this more than anyone... is Bush personally really interested in space-n-travel-n-learning-n-stuff? it just seems dumb to let someone who isn't really interested in this kinda stuff control the direction of Nasa with his flights of fancy. Sure, if he was interested in this kinda stuff then i'd feel fine giving him the reins, but he just doesn't seem like the kinda head in the clouds dreamer that i'd trust waving a paintbrush over the idealistic ARTFORM that is Nasa.

("flights of fancy", and "head in the clouds", are both endeering terms towards Nasa and those running it)

Roid, here's my take. Concentrating on a space craft that is Mars capable instead of the scram jet has a basis in space superiority is something beyond Bush simply being interested in space tech. Back when Kennedy commited our country to going to the moon, this was in direct response to Russia gaining a percieved advantage in space.
Fast forward forty years and the Chinese have stated catagorically their desire to colonise Mars and the moon. Just as with Kennedy, Bush (in reality the american national security end of things) sees a potential threat to our status of super power. In any potential conflict he who controls the high ground wins the war. You undoubtably understand this with american air power so easily dismanteling certain countries air defenses and then ground assests.
If the Chinese commit fully to space and we don't, america will wake up in 40 years and have suddenly have to buy permits (or tickets)to send our citizens
out to visit the planets. While perhaps far fetched, china could very well claim sovereign rights over Mars if they send enough colonists (lord knows they have enough excess people). America will not sit out such a scenario and thus my thinking on why we are more interested in interplanetary craft over a scram jet. After all, now that the scram jet seems operational, I suspect private concerns will pick up the slack and push the development of this technology.

The only problem is that scramjet engines aren't operable in the vacuum of space. You still need to carry a fair amount of fuel and rockets to use it if you want to finetune your trajectory in flight.

Men will land on Mars before a hypersonic passenger craft ever flies.

The X-43 program was designed to find out if a hypersonic bomber capable of striking anywhere on earth in 2 hours was possible.

The answer is: YES.

The cost? Well, seeing as how each Stealth Bomber costs the same as a new space shuttle (around 2 Billion), can you imagine what Mach 10 capable bombers would cost? I'd say 4-6 Billion a pop.

I'm glad they cancelled the X-43C program. It was a smoke screen saying the technology is applicable to space launch technology. I seriously doubt the technology could be validated and qualified for man-rated space-launch operations inside 20 years, even IF the will was there to apply it.

a frightening theory mobi. if that were so they could and WOULD easily make it unmanned anyway, which would significantly drop the cost (considering the G forces involved and nessesary protection/precautions for the pilot).

but i'd still like to think the tech is mainly designed for non-military purposes atm. they seem to be concentrating a lot on it's hypersonic gliding ability, when not thrusting (ie: when it's nothing more than a steerable bullet ). it's wild to think about it, that when it stops thrusting it takes a while for this thing to come back down to subsonic speeds.

remember an australian university did the first successful scramjet atmospheric tests with a megre budget. keeping that in mind, if someone wanted to they could make a scramjet passenger craft.

the X-prise was pretty inspiring, i'm sure for more ppl than just me and you

To put things in perspective all we have to do is look back 40+ years when the x-1 craft were used to try and break the sound barrier. I suspect in another 40 years scramjet tech. will become common place.

40years, ★■◆● that. *presses fastforward* (oh wait that's illegal)

roid wrote:40years, **** that. *presses fastforward* (oh wait that's illegal)

Seriously, i have a hard time believing that it will take a whole 40years for this to go anywhere. It's probabaly just my age talking, but i see things happening sooner than that in the scramjet department. you don't Tyr?

roid wrote:Seriously, i have a hard time believing that it will take a whole 40years for this to go anywhere. It's probabaly just my age talking, but i see things happening sooner than that in the scramjet department. you don't Tyr?

He didn't say it would TAKE forty years for scramjets to become commonplace, he just said that they WOULD LIKELY be more commonplace then. Kinda like stealth rigged fighter/bomber craft are becomming more and more common now vs ten years ago. The technology used to break the sound barrier was undoubtedly expensive back then, just like stealth rigging today costs a pretty penny. Its just a simple combination of factoring in the cost into the equation.

that kinda stealth tech ONLY has military purposes. so if we on earth have a lot of war, then that technology grows faster.

hypersonic engines have more than just military purposes, nasa's been saying this all along.
the motivations driving the research for the 2 technologys are comparing apples and aliens.
there is hardly any reasons for private non-military companys to research/develop stealth technology. there is no thirst for stealth commuter craft. but locomotion technology? ooooh yeah there's plenty of non-military motivation for locomotion technology research, especially of this "limit pushing" caliber.

Yes, but you're ignoring one key factor. Money. Right now it costs a ton of money to build said scramjet. Same as it costs alot of money to build stealth-rigged aircraft. Yes, there is the demand issue, as you mentioned, but its got to be paid for somehow.

but i already mentioned the queensland university's SUCCESSFUL effort, on a meger budget. the HYSHOT program.

cutting through your "you need $!" point like my mouth though a block of cheeze .

i can't see how anyone can be so pessimistic about it. we've had hyshot, we've had x-prize. both on relatively small budgets.

look, it seems that development is still thankfully going on independantly of nasa. they don't hold ALL the reins. at a glance i see mentions of ongoing australian and japanese scramjet projects, no doubt it's not limited to just that.

roid wrote:but i already mentioned the australian university's SUCCESSFUL effort, on a meger budget.

cutting through your "you need $!" point like my mouth though a block of cheeze .

Not exactly. If the research team here ran things just like the AU uni did, then your "cutting through my ponit" would work. However, since NASA more than likely does things just a tad bit differently, its undoubtedly going to cost more money here. Remember, the tech is still in its infancy, so its going to cost more until we can find a more efficient way of replicating it.

The only down side to commercial/private hypersonic applications is best exemplified by the concorde jet.
While there was a interest in faster commute times, the realities of noise and maintenance cost finally shut the concorde down.

iirc there are already supersonic commuter planes in manufacture right now of different safer and more efficient designs, to replace the gap left by concorde. the concordes are a pretty old design.

the concordes were plauged by design flaws. iirc they also wern't designed very efficiently, so they were VERY expensive to run. this isn't the case with in-production supersonic craft.

supersonic craft are a lot different to hypersonic craft however. the stresses and dangers involved in hypersonic flight are jawdroping indeed. what makes it even more complex is that a hypersonic "cruise" craft has to first accelerate though supersonic speeds before it can engage it's hypersonic scramjet drives to cruise with.

but hey, it sounds like a challenge

but alas, i am getting ahead of myself. the quoted reasons for designing/using a common hypersonic craft are really just to make space more accessable with common space shuttles, not for cruising from L.A. to Sydney (scaring Hawaii in the proccess). when upto speed you burst your hypersonic engines for as long as there's air to be breathed. if the technology is upto it, then this itself may enable you to apogee into space. but if not then a small solid rocket boost wouldn't be astray.

sure it's a lot of seperate engines to carry on one craft, but the savings in fuel weight (as well as cost per litre, sir arabs) outweigh it. also the savings of a simple horizontal takeoff.

common payloads and common ppl can goto space. yay for space.

roid wrote:iirc there are already supersonic commuter planes in manufacture right now of different safer and more efficient designs, to replace the gap left by concorde. the concordes are a pretty old design.

the concordes were plauged by design flaws. iirc they also wern't designed very efficiently, so they were VERY expensive to run. this isn't the case with in-production supersonic craft.

Yeah, one of them IIRC won't have any forward facing windows. The only way for the pilot to see outside is via hull mounted cameras. However, that itself presents a big problem if power fails to the cameras and they have to make an emergency landing. Then again, they wouldn't be able to see the runway anyways with the steep angle they'd have to come in at to land.

supersonic craft are a lot different to hypersonic craft however. the stresses and dangers involved in hypersonic flight are jawdroping indeed. what makes it even more complex is that a hypersonic "cruise" craft has to first accelerate though supersonic speeds before it can engage it's hypersonic scramjet drives to cruise with.

Yup, they'll have to use conventional means of reaching enough altitude and speed to make use of the scramjets. Even then, they'll have to either take it easy on the gas, or give everyone their own flightsuit. I haven't done the calcs on the G forces alone, but I imagine they'd be rather high. Not something someone with a large waistsize or an elderly person could handle very well.

sure it's a lot of seperate engines to carry on one craft, but the savings in fuel weight (as well as cost per litre, sir arabs) outweigh it. also the savings of a simple horizontal takeoff.

common payloads and common ppl can goto space. yay for space.

Wouldn't the structural bracing needed to enable the craft to handle previously mentioned stress add to the weight by quite a bit?

MD-2389 wrote:Wouldn't the structural bracing needed to enable the craft to handle previously mentioned stress add to the weight by quite a bit?

probabaly. all the impracticalities considered, it's still better than current shuttle vertical launch techniques.