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Very interesting. Any idea on the power requirements and cost?
I still think making a numerical model is more important than a visual model. Maybe I'm wrong though. I guess it depends on your immediate goals and audience.
I'll have to think more on it and do some more calculations on the feasibility.
Any idea which mountain? Arizona you say?
Why not magrails? Well this sounds a little like a mass driver, although it sounds like you want to use a mechanical catapult.
Maybe you should do the math before you do the animation.
Launching humans is a bad idea. After you do the math, how many g's will people be subject to?
Going back a little... the reason we are not going to Mars Directly or even it's moons, is because that is not the plan. We have a plan set out in front of us...to go to the Moon, then to Mars and then beyond.
Whether we like it or not, that is the path that we've got. There will be challenges to overcome on the Moon and those challenges will lead to skills and technology that will allow us to remain there (and other locations) longer and with greater enterprise.
Colonization is possilbe although unlikely in the next 20 years. We could have sustained human presence on the Moon and even on Mars by then. But we won't because there is no follow-through. Also, we don't all have our books out calculating the delta-v savings, costs, masses, and times that everything takes. Instead we have our popular science out reading what some fringe science reporter thinks.
A good place to find out information on rockets is the International Reference Guide to Launch Vehicles.
I think GCN mentioned that the Soyuz hatch is too small to mean that you couldn't put Cosmos 1 in the Soyuz vehicle. The Soyuz rocket (which typically carries the Soyuz and Progress modules) would have been sufficient to carry Cosmos 1.
Wow I didn't realize Italy's economy had grown so much. Read your newspaper.
The F-22 is nice, but it's designed to do too many things. When you want something to be a bomber, a dog-fighter, a ground support fighter, get there in a hurry and be stealthy doing it, you are going to have to give somethings up.
Fortunately, these are the same things wrong with the Eurofighter.
China is a growing force. They have a lot of momentum, but they are going to take time to mature. They are going to need to launch several more taikonauts before they are prepared for the more serious mission of landing men on other worlds.
Good luck to them though. Now let us get moving.
You should be able to find them at http://atlas.ae.gatech.edu/main/publica … index.html.
This sounds exactly like the Starrunner concept that I presented at the last Joint Propulsion Conference. We used turbine low speed, ram/scram high speed and then rocket orbital speed. All was integrated into the same engine with the ACES. This was a large concept vehicle as it was for a large payload (something on the order of an ISS module), but the ideas are interesting. In hindsight, I think we would have done somethings different. An RBCC sounds more attractive for simplicity. If you really like to learn about RBCC spaceplanes check out the Hyperion concept by Dr. John Olds of Georgia Tech. StarRunner you can read about in AIAA 2004-3729 and the Hyperion you can read about in AIAA 99-4944.
Only leading edges (wings, front edges and cowl leading edges) as well as the engine itself need significant thermal protection. There are materials (such as the TUFI tiles and thermal blankets used for the shuttle) but there are also newer materials with TRL (technology readiness level, NASA's way to measure how feasible a technology is to use in its current state) that are high enough to warrant using them rather soon. One comes to mind, Hafnium Diboride. It's been a while so don't crucify me if this is a little off, but this material would offer both the thermal protection needed and the reusability that the materials the shuttle uses do not offer.
Concerning reentry profiles, GCN is right. Two things are contingent on velocity: (1) your orbit is determined by it, so the slower you go the closer or lower your orbit, and (2) the amount of energy (heating) is transferred to your vehicle via fluid friction. The faster you go the hotter you are. So there is this trade, you either stay higher and fast (and away from air) or low and not quite so fast (and burn up, and hopefully you have some Hafnium Diboride wing edges). But the trick is that you cannot slow down with droping fast.
It's difficult to remain at a certain orbit while decreasing your velocity with out aerodynamic effects (and those are the same aerodynamics effects that are causing you to slow and heat up), lose-lose.
Hypersonics depends on a handful of technologies to emerge before they become reasonable. Concept X-planes have been experimenting with the ideas, but they are no where near the level of reliability that would be required for non-experimental purposes.
Somethings that need to happen: high-temperature/high-strength materials (for the engine and leading edges), more knowledge of injection dynamics for hypersonic flow and hypersonic flow in general, and some serious research in control systems needs to happen. It's nice to think about, and it's decent research, but if you're interested in going to space in the next 20 years put your money somewhere else.
One thing that I will never forget, told to me by astronaut John Young is that "all single planet species, are bound to become extinct."
I think what most people don't realize is that we have launched many nuclear powered vehicles (although RTG's and not what we're talking about). We have to be careful, but don't we always?
Yeah I don't think scramjets are very feasible for single person use. I'll have to give that one some more thought.
I completely agree that there are technology hurdles. Even though I have done research on the matter, I have my doubts at the same time. I'm an old-fashioned sort of guy when it comes to real hardware. Paper studies are one thing. But they are mostly thought experiments.
I am a strong proponent of NTRs. They are realistic, powerful, efficient, and can be built and operational sooner than air-breathers I think. There are legal hurdles though.
Does this operated like Nuclear Thermal Rocket? Would you launch from orbit?
Scramjet top speed is mach 25 (maybe higher).
The rocket equation that you are talking about is the "ideal rocket equation". A rocket is just a device for momentum transfer. This doesn't mean that you have to bring all of your medium with you. Under these 'non-ideal' circumstances the equation has to be modified. Other things that can effect the rocket equation are aerodynamic effects.
Bringing a giant powerful magnet-superconductor would be prohibitive I think.
Small private scramjet planes are not feasible. Ramjet ...maybe. I think there is something on it at the Joint Propulsion Conference. Maybe I'll report back when I get back.
One more quick thing: Mars Direct won't see any direct benefit from the X-Prize. The best we can hope for there is that people might get excited and tell their governments to spend more on spaceflight and less on wars. Does anyone have the dollar amount spent on the 'war on terror' and the sum of NASA budgets since then for some head-to-head comparison?
Mars Direct is a ten year old plan. All ten year old plans have shortcomings. But I'm guessing that what you're implying by saying "stock unmodified" form is that you think it would work in some modified form?
To GCN: No insult intended, it's just that I know what the Rocket Eq is too.
To Flash: The atmosphere does extend farther than Rutan's ship, but you have to remember the density of the atmosphere like the Ideal Rocket Equation, is exponential. So the higher you go, the faster the air thins.
Scramjets are a beautiful technology. You have to be going very fast though, and you have to have a fine tuned design. Because we know so little about the effects on air at that velocity it is difficult to make a robust craft. Another extremely important thing to keep in mind is that scramjets will not work outside the atmosphere, and their efficiency depends on the density of air. To go fast enough to use scramjets in air that is dense generates a lot of heat on the leading edges of your craft. So its a trade. But all of the projects that I have been on that have dealt with scramjets have shown that they can be help out a lot.
Quickly, a scramjet is simply a rocket. The only difference is where you're getting your oxidizer. You compress air using an inlet, and then ignite fuel in the flow (tricky). There is a technology called ACES (Air Collection and Enrichment System). This is used to collect O2 in flight (one so you can have it when you leave the atmosphere, and two so you don't have to take off with it, which might be prohibitive). It can be heavy though, so currently would only be useful on larger vehicles.
The Tsiolkovsky Rocket Equation is exactly what I am talking about. You see I ran SSO's numbers through the rocket eq. and got results that did not agree with your numbers. I was just wondering if you had run the numbers yourself or if you were quoting someone.
Let me introduce you to one of the facets of the rocket eq. Staging is when you launch a rocket, and when you reach a particular altitude and/or velocity you disconnect your vehicle from part of your launch vehicle and continue on with reduced mass. This makes life a little easier. Then you could either dispose of the stage or have some method of sending it back to reuse later.
I'm not suggesting that SSO could launched on a conventional staged rocket. Re-entry from that velocity would be out of the question. This brings me back to SSO is not designed to be a conventional vehicle.
I can respect a realist. I also respect someone with vision. If you think that we're not ready for the sky until 2050, why are you here? Obviously, you have some kind of vision.
P.S. The 'exotic' technology I was referring to was the hybrid rocket motor. It's been conceived of, and even used experimentally to some lengths, but going from that to a human rated sub-orbital craft...exotic.
I think we have to realize something. SSO was not designed to go to 200km. It was designed to go to 100km. Given some clever staging the vehicle weight you are quoting (send me the math) could be brought down significantly.
The response to the XPrize was, exactly that, a response to a set of requirements. The money invested, the knowledge gained (whether you like it or not, Burt did have some exotic technology being evaluated on this trip) and the public awareness/interest that resulted in SSO is important.
GCN, I haven't read all of your emails, but are they all this defeatist and down? Maybe you could tell us what you think will work. Your profile doesn't reveal much.
It is hard to support a shuttle with a downturned economy. But here we are now 35 years after we walked on the moon, and now we're trying to think of a the best to get to the moon. For all the money and time we spent the US is going to take 15 years to return. We are no closer than the Chinesse.
We should take clark's advice and learn from our mistakes.
I don't know how we are going to garner the public support, but if we are going to go anywhere, we must.
I think it's important that people be aware...of other cultures, and space ideas.
Your idea sounds similar to the space elevator. And one of the design requirements that comes to mind as I read your paper is that the moments that will be acting on the bottom half of this structure from both the rotation of the Earth and gravity gradient. They solved it with the space elevator by making the center of gravity at geosynchronous orbit. This makes it far enough above the atmosphere not to have that interference and of course the gravity is passing through the center of mass.
Just something to think about.
Does anyone on this forum plan on attending the AIAA Joint Propulsion Conference about 4 wks from now?
They are going to have some really interesting papers being presented on solar sail concepts.
Does anyone know of any good design tools for simulating/modeling solar sails?
I think that it's really important that people make the case to everyone why we should explore space.
Someone needs to really ignite the public generally. They have to really want their money to be spent on space (human and robotic) exploration.
I also know that a writer or journalist could accomplish this well. I couldn't see it happening though on a small mission (4 to 6) unless someone was cross-trained as a historian or writer.
I have to agree with GCN. Orbiters were and are a bad idea. However, the US has no capability to rendezvous autonomously, and as far as I know neither does the ESA. The Russians have been doing for decades though.
Tugs are 90% a bad idea. They have some applications for reboost, but the cost to develop and operate just does not fit into the plan right now.
We do need better docking. The Chinesse have a lot to learn yet before they will be able to compete with the rest of us. The ESA does not deal with manned systems. The Kliper...hard to say. I'm not really sure where you all are getting your information on the CEV and the Kliper. A final design on the CEV has not been chosen as far as I know. If you know, send a link. Kliper is Russian, we won't know until it's flying. But it will likely not be effective for much more than orbital flights.
Finally, we should get over the shuttles as soon as we can. Space will be the future of mankind, and whatever that entails (war, etc.).