The other reply to your question is misleading. Yeas you need to get to Mach 25 to achieve LEO, but there is no benefit to accelerating the entire craft to that speed. Why would you send people to LEO? You send satellites to LEO. Satellites don't weigh that much relative to a launch vehicle, so a third stage rocket used to boost the satellite from the "edge of space" to LEO wouldn't have to be that big.
The only real issue with the third stage is integration with the first two stages. External mounting would add a lot of drag during the low-altitude flight segment. The thrid stage could be held inside the second stage craft which would protect the satellite and reduce performance penalties to the first and second stages. Ideally, the third stage could be launched out the front of the second stage, but the use of a human pilot prevents that because the cockpit is in the front.
I would say that you haven't completely missed something. A lot of people can't shake the Shuttle paradigm of accelerating the entire vehicle to orbit and not just the payload. Thanks for the good question!
-Robert
It's actually a combination of speed and height, kinetic and potential energy - you can trade the two against each other. The Space Shuttle has everyone caught up in this idea that the vehicle itself has to make it to LEO, but why? If LEO is the target because that's the orbit you want for your satellite, then you only have to worry about getting the small weight (relative to the launch vehicle) of the satellite up to LEO. If you can carry a rocket up to the edge of space with a craft like SpaceShipOne, and launch it from there, it's a lot easier to get your satellite up to LEO. There's no reason to accelerate the whole plane up to that altitude/velocity! By taking advantage of this, the reusable part of the launch vehicle doesn't experience ridiculous temperatures on re-entry like the Shuttle and the vehicle has a significantly higher chance of repeated survival.
I'm proud of Scaled! I've worked on designs like this and I didn't think the primes/politicians would ever let something like this be built! Good luck with Tier Two!
It takes the Shuttle to so long to relaunch because the entire craft needs to be recertified before relaunch. That is because the design has virtually no margin, so under normal operating conditions there are components that are on the verge of failure. These components must all be inspected and potentially replaced before another flight can occur. A small, reasonably designed vehicle should be able to hit a two week turn around no problem. DARPA's RASCAL and FALCON programs require a 24-hour turnaround.
If you can make a plane go Mach 7, you can use it as a first stage in a two-stage-to-orbit reusable launch vehicle. Remember that a plane traveling at Mach 7 has a ridiculous amount of kinetic energy, which can be converted to potential energy (altitude) by performing a pull-up maneuver. This allows the rocket (second stage) to be released at an altitude and velocity high enough that only one rocket stage is required to lift a satellite into orbit. Because the rocket can be a single-stage now, it can be designed to return to Earth and be reused, drastically reducing launch costs and making launch from a range unnecessary (sufficient redundancy can be built into the plane to make it safe, plus you don't have to worry about multiple rocket stages re-entering the atmosphere.
Traveling at this speed creates immense levels of heat (temperature increases with the square of the mach number, i.e 4x higher temp at Mach 4 than Mach 2 [16/4], 25x higher temp at Mach 7 than Mach 2 [49/4]!). Luckily, this is only true in the atmosphere, when air molecules are being decelarated from Mach 7 to 0 on the plane's surface. If a plane can go fast enough to leave the atmosphere, it can significantly reduce its heat load. It can then periodically trade its potential energy for kinetic energy and rapidly transverse the globe exo-atmospherically (this is the concept the Germans came up referred to elsewhere). The plane heats up again as it re-enters, but unless it continues to accelerate in space, it will re-enter at a velocity slower than it's exit velocity, so the worst heating case is on exit, which it already survived! The costs of the initial build for such planes is high because the materials that can withstand these speeds are so expensive (Inconel, etc) but the ability to reuse the entire vehicle significantly reduces launch costs. Sadly, the space industry is government subsidized and competition averse, so there is little motivation to change the status quo. In government contracts, the less expensive your product, the less money you make.
The batteries in a laptop will give you the flexibility to work independently (for an obviously limited time) of your home's power source. This might come in handy if you have a solar system that has intermittent output or oyou have other high-draw electrical needs.
First, the problem that caused the Columbia failure was not in the Shuttle's wings, but that its fuel tanks were designed with insulation that can fall off! Commercial airplanes don't have in-flight wing repairs because the FAA wouldn't let them fly if pieces of them were allowed to fall off. Then, if something did malfunction, the mission(flight) would be aborted, not continued until there was no hope for a safe return.
I worked for a company that has designs sitting on the shelf of replacement fuel tanks for the Shuttle with internal insulation (it can't fall off that way!) that weighed 50% less than the current models. All with existing technology.
The frustrating thing about NASA and aerospace in general is that 'unobtanium' isn't necessary for inexpensive access to space. Reusable launch vehicles can be built with existing technologies and materials, I've designed one under DARPA's RASCAL program. The problem is that there's too much money to be lost by replacing the Shuttle. A standard government contract includes a 10% profit margin, and there are no incentives for coming in ahead of schedule or under-budget. Therefore, companies lose money by supplying the government with less expensive products, because the total value of their contract decreases. You'll notice that the same companies that bid on NASP and every other 'Shuttle replacement' are the same companies that support the Shuttle. It would only undercut their profit margin to develop a more reliable and inherently less expensive vehicle. This is also because the government is their only remaining customer, and since they obviously don't hold them accountable for an inferior product, why should they change?
There is no longer much of a commercial satellite industry in the US as a result. The government gave loan guarantees to cable companies so they could install cable across the country. This resulted in a huge infrastructural overhead that forced the cable industry to offer their services at a loss in order to compete with the satellite television providers. Luckily, when the cable companies went bankrupt and defaulted on their government loans, they no longer had this overhead and can now operate at a profit will undercutting satellite service costs. Now the risks associated with commercial satellite service in the US is so high, that these companies have left (to France) or gone under. So, not only has the government insure that we can't readily launch satellites, but they helped bankrupt the companies that would even use the services in the US.
Man, aerospace is frustrating...
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The other reply to your question is misleading. Yeas you need to get to Mach 25 to achieve LEO, but there is no benefit to accelerating the entire craft to that speed. Why would you send people to LEO? You send satellites to LEO. Satellites don't weigh that much relative to a launch vehicle, so a third stage rocket used to boost the satellite from the "edge of space" to LEO wouldn't have to be that big. The only real issue with the third stage is integration with the first two stages. External mounting would add a lot of drag during the low-altitude flight segment. The thrid stage could be held inside the second stage craft which would protect the satellite and reduce performance penalties to the first and second stages. Ideally, the third stage could be launched out the front of the second stage, but the use of a human pilot prevents that because the cockpit is in the front. I would say that you haven't completely missed something. A lot of people can't shake the Shuttle paradigm of accelerating the entire vehicle to orbit and not just the payload. Thanks for the good question! -Robert
It's actually a combination of speed and height, kinetic and potential energy - you can trade the two against each other. The Space Shuttle has everyone caught up in this idea that the vehicle itself has to make it to LEO, but why? If LEO is the target because that's the orbit you want for your satellite, then you only have to worry about getting the small weight (relative to the launch vehicle) of the satellite up to LEO.
If you can carry a rocket up to the edge of space with a craft like SpaceShipOne, and launch it from there, it's a lot easier to get your satellite up to LEO. There's no reason to accelerate the whole plane up to that altitude/velocity! By taking advantage of this, the reusable part of the launch vehicle doesn't experience ridiculous temperatures on re-entry like the Shuttle and the vehicle has a significantly higher chance of repeated survival.
I'm proud of Scaled! I've worked on designs like this and I didn't think the primes/politicians would ever let something like this be built! Good luck with Tier Two!
It takes the Shuttle to so long to relaunch because the entire craft needs to be recertified before relaunch. That is because the design has virtually no margin, so under normal operating conditions there are components that are on the verge of failure. These components must all be inspected and potentially replaced before another flight can occur. A small, reasonably designed vehicle should be able to hit a two week turn around no problem. DARPA's RASCAL and FALCON programs require a 24-hour turnaround.
If you can make a plane go Mach 7, you can use it as a first stage in a two-stage-to-orbit reusable launch vehicle. Remember that a plane traveling at Mach 7 has a ridiculous amount of kinetic energy, which can be converted to potential energy (altitude) by performing a pull-up maneuver. This allows the rocket (second stage) to be released at an altitude and velocity high enough that only one rocket stage is required to lift a satellite into orbit. Because the rocket can be a single-stage now, it can be designed to return to Earth and be reused, drastically reducing launch costs and making launch from a range unnecessary (sufficient redundancy can be built into the plane to make it safe, plus you don't have to worry about multiple rocket stages re-entering the atmosphere. Traveling at this speed creates immense levels of heat (temperature increases with the square of the mach number, i.e 4x higher temp at Mach 4 than Mach 2 [16/4], 25x higher temp at Mach 7 than Mach 2 [49/4]!). Luckily, this is only true in the atmosphere, when air molecules are being decelarated from Mach 7 to 0 on the plane's surface. If a plane can go fast enough to leave the atmosphere, it can significantly reduce its heat load. It can then periodically trade its potential energy for kinetic energy and rapidly transverse the globe exo-atmospherically (this is the concept the Germans came up referred to elsewhere). The plane heats up again as it re-enters, but unless it continues to accelerate in space, it will re-enter at a velocity slower than it's exit velocity, so the worst heating case is on exit, which it already survived! The costs of the initial build for such planes is high because the materials that can withstand these speeds are so expensive (Inconel, etc) but the ability to reuse the entire vehicle significantly reduces launch costs. Sadly, the space industry is government subsidized and competition averse, so there is little motivation to change the status quo. In government contracts, the less expensive your product, the less money you make.
The batteries in a laptop will give you the flexibility to work independently (for an obviously limited time) of your home's power source. This might come in handy if you have a solar system that has intermittent output or oyou have other high-draw electrical needs.
First, the problem that caused the Columbia failure was not in the Shuttle's wings, but that its fuel tanks were designed with insulation that can fall off! Commercial airplanes don't have in-flight wing repairs because the FAA wouldn't let them fly if pieces of them were allowed to fall off. Then, if something did malfunction, the mission(flight) would be aborted, not continued until there was no hope for a safe return. I worked for a company that has designs sitting on the shelf of replacement fuel tanks for the Shuttle with internal insulation (it can't fall off that way!) that weighed 50% less than the current models. All with existing technology. The frustrating thing about NASA and aerospace in general is that 'unobtanium' isn't necessary for inexpensive access to space. Reusable launch vehicles can be built with existing technologies and materials, I've designed one under DARPA's RASCAL program. The problem is that there's too much money to be lost by replacing the Shuttle. A standard government contract includes a 10% profit margin, and there are no incentives for coming in ahead of schedule or under-budget. Therefore, companies lose money by supplying the government with less expensive products, because the total value of their contract decreases. You'll notice that the same companies that bid on NASP and every other 'Shuttle replacement' are the same companies that support the Shuttle. It would only undercut their profit margin to develop a more reliable and inherently less expensive vehicle. This is also because the government is their only remaining customer, and since they obviously don't hold them accountable for an inferior product, why should they change? There is no longer much of a commercial satellite industry in the US as a result. The government gave loan guarantees to cable companies so they could install cable across the country. This resulted in a huge infrastructural overhead that forced the cable industry to offer their services at a loss in order to compete with the satellite television providers. Luckily, when the cable companies went bankrupt and defaulted on their government loans, they no longer had this overhead and can now operate at a profit will undercutting satellite service costs. Now the risks associated with commercial satellite service in the US is so high, that these companies have left (to France) or gone under. So, not only has the government insure that we can't readily launch satellites, but they helped bankrupt the companies that would even use the services in the US. Man, aerospace is frustrating...