49

This post highlights some misconceptions, so let's do this with big letters. Launch is about going fast, not high A helium balloon will get you to the edge of space. It takes a large and expensive rocket to get into orbit. Ok, one at least 20 m long. Very very fast "But the plane can give you 600 mph" you say. Well, that's nice, we have 268 m/s of ...


33

Here are a few disadvantages to air launch: Most launch vehicles are too heavy to be carried by any extant aircraft, e.g. Atlas V 401 masses 335 tonnes, compare to the Airbus A380's maximum load of 89 tonnes. For launch vehicles with cryogenic propellants, loading and topoff would be extremely challenging. It is generally not safe for personnel to be closer ...


32

You're confusing units. The maximum speed of the X-15 was 7274 km/h, or about 2 km/s. Orbital speed is around 8 km/s. The X-15 didn't carry enough fuel to reach orbital speed.


20

Nearly all balloons that have been constructed have been for flights from the surface to altitude. That requires a structure that can survive tethered at the surface in a range of wind speeds in high-density air, then expand to several times their original size in order to maintain lift as the air density decreases. The minimum density ends up being ...


19

Air launch does not actually provide that much benefit. The benefits are basically, that starting at 40 or 50,000 feet allows the following: The nozzle can be closer to vacuum optimized on the first stage which is good. The launcher can fly to the equator, for a 0 degree inclination launch which is useful. But as noted, the mass limits on the booster ...


13

As noted on the wikipedia page on air launch to orbit, This article has multiple issues. One issue is that it compares a vehicle launched from an aircraft versus a similar vehicle launched vertically from the ground. That's not a good comparison. A better comparison would be to look at the aircraft that carries the rocket as a substitute for the first stage....


11

That depends upon what would satisfy your needs as an "orbit". I think its unlikely to do what you are hoping. A good way of thinking about the problem to make it more intuitive is to say that there is a rule that applies to all satellite orbits that, aside from the effects of the atmosphere, from the point that a manoeuvre ends the satellite will conduct ...


11

To float something at 140,000 feet (> 42 km) requires an impossibly low density structure. At 40 km the density of air is less than 4 grams per cubic meter. Barely attainable with the lightest of balloons. The proposed added structures, engines etc make it quite impossible. As to making a balloon structure ascend to orbit, again impossible. The drag will ...


7

I came across a fairly detailed comparison made by the team that worked on Interim HOTOL. Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s For Interim Hotol: speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s drag loss: + 67 m/s gravity losses: - 670 m/s Isp underexpansion ...


6

I think it's possible that the airship can go hypersonic which is already a major achievement if it does. If they can reach Mach 12 then it could be combined with momentum exchange tether assist to get to orbit. That's still a big ask though. [ see also this paper For details of HASTOL system see this paper. I'm not so sure about accelerating to orbit ...


6

Lots of good stuff on this topic in Wikipedia.: Air Launch to Orbit Air Launch A typical rocket spends the first few seconds going straight up (almost) to get out of the atmosphere. After that it spends almost all of its time accelerating to orbital velocity. Thus getting out of the atmosphere, while hard (rocket is heaviest at this point) is really only a ...


5

A mostly un referenced list would include: Needing to design rocket structure to bear load horizontally pre launch as well as vertically under thrust. Classic rocket design supports the rocket against 1G at the engines using the same structural elements that must handle several Gs in flight anyway so ground based support are largely 'free' other than ...


5

The difference between launching from the equator versus launching from Florida works out to about 55 m/s. Total velocity budget required to reach LEO is around 9400 m/s, so the difference is about half a percent. To launch Pegasus from the equator, the L-1011 would have to take off from Florida, fly 3000 km south, launch, then fly 3000 km home -- pretty ...


5

Yes, the rules are the same for an air-launched vehicle. From a 2008 paper describing the FAA's approach ("Separation Distances for Rocket Launch Operations" AIAA 2008-7124) the permit applicant must identify and qualitatively characterize the risks of each of the potential hazards associated with its proposed operation and apply mitigation measures ...


4

The picture above shows a picture of Space Ship One. on the jet powered 'carrier aircraft'/'mother ship' White Knight - that probably counts as an Aircraft. However, I think these designs are only designed to reach low-earth orbit, not up high enough t carry a satellite, carry cargo to the ISS, etc


4

Balloon lifts for sounding rockets is certainly a thing, but they are at the right end of the effects of scale on balloons and safely launching them. If you take this high altitude balloon as an example, getting 600kg to 39 km uses a balloon 100 meters across. Scaling that to 600 tonnes is jumping the decimal point three places and even with cube law ...


4

Historically range safety has destroyed 2 airlaunched boosters that I know of, the 6th and 9th Pegasus launches. It appears that these were destructed because of obvious loss of control issues rather than corridor breaches though. So: Range safety is a player and will/historically has destruct(ed) air launched vehicles. I do not have the details on the ...


4

The X-15 didn't have the capability to get to orbit, and it was never intended to. the X-15's purpose was not space flight but to test aerodynamic heating at high altitude and high speed. It's skin was designed to tolerate a great deal of heat, but nowhere near what would be required for re-entry from orbital velocity. If it went to orbit it would burn up on ...


4

The design constraints for air launch are more about the first stage being able to light while horizontal (no fuel sloshing away from intakes), and the structural additions to support being hung fully laden sideways rather than vertically in the same direction as thrust loads. There also needs to be the flight controls to achieve the pitch up, which may ...


3

They're back to their old plan of launching Pegasus XL. In a statement to SpaceNews, a company spokesman said that the company was ending work on its own family of launch vehicles and would instead use its aircraft for launching small Pegasus XL rockets from Northrop Grumman. News of the change in plans was first reported by GeekWire. “Stratolaunch is ...


3

Much the same reason as no current commercial aircraft is supersonic, drag/cost climbs substantially and the aerodynamics becomes much more complex given the need to take off subsonic and fly supersonic. Notably This drone gives an example of the challenges and constraints of getting an external payload above mach one and separating it cleanly. the listed ...


3

The X-15 was undoubtedly fast enough to reach altitudes at which the pilot could have looked into the blackness of the heavens, but high altitudes are not enough for achieving an orbital trajectory. I know this doesn't exactly answer your question (and others have already explained the difference in units), but there's also a misunderstanding about ...


2

Assuming the rocket has its full payload mounted and ready, is fully fueled, and is pointing roughly the right direction, there's no reason it couldn't launch without having a launchpad underneath it. With that said, rockets sometimes have last-minute aborts where the engines are ignited and everything looks ready to go, but the computer cancels the ...


2

Another problem that would rear it's ugly head if you were to try this: Wake turbulence. Your satellite will be leaving the barrel at a stupendous velocity. It's going to slam into the atmosphere in front of the plane as it goes. Your launching aircraft is going to slam into that turbulence. I would be very surprised if that wasn't followed by pieces of ...


2

Is it possible? Yes, but not with current technology (sorry not sorry for that pun). Right now railguns can't shoot projectiles fast enough to launch picosats from altitude. At least that's what my back of the envelope calculations say, maybe someone will check my math. Let's use the General Atomics 32 megajoule (MJ) Multimission Medium Range Railgun ...


1

Air Launch has its limitations listed in previous answers but also have a number of benefits. The delta V gain is not the most important. More important may be the air launch immunity to moderate weather related problems. You know how often the space launches delay because “shear winds” constrains. The other may be most important benefit is that the air ...


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