13 ms·
In California, giant Stratolaunch jet flies for first time
- tyingq 8y agoI'm curious what the emergency landing options are for this thing. It looks like there would be limited places it could land with that wingspan and landing gear spread. Edit: Curious, not critical. Maybe it can land in a lot of places, just reacting to the size.
- deleted 8y ago[deleted]
- degobah 8y agoSince its purpose is to launch rockets, I assume it lands where it takes off, and might never stray far away.
- tyingq 8y agoThat's the sort of thing I'm interested in. Like, for example...how far away are you once you get this huge thing high enough to launch. I'm not trying to criticize it, I'm just curious how dangerous a typical mission will be.
- not_a_terrorist 8y agoIt only reaches 35,000 feet.
- mikeash 8y agoYou can make occasional turns to keep close to the airport while climbing higher. I don’t know if that’s what they’ll do, but this problem has some easy solutions at least.
- 0xffff2 8y ago> Like, for example...how far away are you once you get this huge thing high enough to launch. It can climb in a circle so that it's never far from its base.
- cmurf 8y agoIt doesn't have to fly in one direction, it can do s-turns while climbing, or circle. I think clearly payload launch is the risky part. What are the kinds of launch failures? Rocket engine failure can be uncontained and spectacular.
- inamberclad 8y agoThey're going to move it all over the world (or at least, over the latitude range) in order to get into the most optimal launch position.
- deleted 8y ago[deleted]
- base698 8y agoWas there for this flight yesterday, and with someone who worked on the project. Most runways are too narrow for both the wingspan and wheel span. It is quite limited in areas it can land and take off.
- bronco21016 8y agoWith an option to jettison the payload I would imagine it can land relatively short. The majority of stopping distance is related to having enough rubber on pavement and keeping brakes cool enough. Stopping energy required changes dramatically as weight is reduced as it’s less energy required to stop and a slower touchdown speed. I’m not sure how the dimensions of the aircraft affect its ability to use other airports though and exiting a shorter runway after repair can also present a major challenge.
- salawat 8y agoMe too. I have serious questions in regards to maximum landing weight, will or won't the payload have to be jettisoned, and whether there will be propellant restrictions. Imagine an emergency scenario where a high payload of hydrazine/NTO/UDMH/MMH has to be dumped at low altitude to recover the plane "safely". With a traditional vehicle you at least will never have an incentive to take your launch vehicle anywhere where down range includes a low altitude intersect with a population center. This on the other hand... Oof. This brings an entirely new dimension to Range Safety. I can see the lesson having to be relearned the hard way if we aren't careful. Not saying it isn't worth it, but man, those postmortem would not be fun. Would be a hell of a thing to see go off without a hitch though.
- yonkshi 8y agoThis is such a cool concept, I really wish these guys would succeed. Though last time I heard they gave up developing their own rocket (as a second stage to space). Anyone who's in the loop, does Stratolaunch currently have any potential rockets lined up?
- exochrono 8y agoArticle states that they're going to use Northrop Grumman's Pegasus XL.
- kryptiskt 8y agoThey have been contracted to launch Pegasus XL rockets.
- not_a_terrorist 8y agoThey abandonned all development activity of their own rockets, shortly after Allen's death.
- shereadsthenews 8y agoThe concept is indeed good, which is why people have been air-launching Pegasus rockets for decades. I’m actually not sure what the new thing is with this aircraft. Just that it can launch three rockets per flight?
- eismcc 8y agoHow did they prevent the two fuselages from torquing the wing apart? Seems like keeping both “sub-planes” from ripping the middle wing apart would be challenging.
- hliyan 8y agoThis was my first thought as well. But then I remembered that modern twin-engine commercial jets can fly with one engine down in an emergency. Not an aircraft engineer, but I suspect the structure is strong enough to handle normal torques during turning.
- PopePompus 8y agoHeavy turbulence might be exciting, though.
- base698 8y agoThe complications with flying a twin engine during a single engine failure have more to do with flight characteristics than structural. Ie, does the rudder have enough authority to stop a spin or does the engine provide enough thrust to maintain level flight.
- eismcc 8y agoThe stratolaunch looks to have 2 rudders making things even more exciting.
- deleted 8y ago[deleted]
- CarVac 8y agoActive control systems, presumably.
- vpribish 8y agothe center wing structure is strong
- 8y ago
- sfifs 8y agoI'm puzzled by what added benefit being 10km up in the air and going at 300-400kmph gives over regular rocket launches since speed and altitude are a very small fraction of what's required to orbit. The article says it will be less affected by weather windows but (1) would a normal LEO commercial launch be so highly time bound to find this of value? (2) if weather was bad for a rocket launch on surface, would you fly a heavily laden giant plane into it? Leads me to wonder if the real customers of this is the military who do value very short turnaround launches.
- alex_anglin 8y agoIt's probably a more enjoyable launch experience for passengers.
- mikeash 8y agoThe amount of rocket you need to reach a given speed is exponential with respect to that speed: https://en.m.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.m.wikipedia.org/wiki/Tsiolkovsky_rocket_equation Shaving off a small amount of speed can have a large payoff. This is why most launch sites are near(ish) the equator.
- simonh 8y agoThat's not actually a very big effect compared to mid latitudes. The main reason to launch near the equator is because a lot of payloads go into equatorial orbits and plane changes are expensive. From the equator you can go into any orbit equally easily (because you just wait for the earth to rotate until you’re on the desired orbital plane), but the only way to go into an equatorial orbit without a plane change is from the equator.
- mikeash 8y agoThat’s a big effect, certainly, but the payload boost from the additional speed is still significant. You can’t really get into any orbit equally easy when launching from the equator. The higher the inclination, the more delta v you need. For example, the Shuttle lost several thousand pounds of payload capacity when launching to the ISS compared to what it would have been able to carry to the Space Station Freedom, which would have been at an inclination matching KSC’s latitude. It’s just that the penalty is vastly worse for launching into a low-inclination orbit from high latitudes (thus why we didn’t tell the Russians to suck it and deal with an inclination better suited to KSC).
- dweekly 8y agoScott Manley walks through why this isn't helpful yet since they have nothing useful to launch in delightful detail (complete with Kerbal simulations): https://youtu.be/yw84qJIGZeo https://youtu.be/yw84qJIGZeo
- jessriedel 8y agoThat's not a good summary. Yes, the plane is not very valuable in the short term (~4 years) because the only viable existing air-launched rocket is the pegasus, which is old and can be more cheaply launched on the smaller planes for which it was designed. But as Manley emphasizes, the whole stratolaunch plan is predicated on developing a new air-launched rocket, and we just don't know what the specs on that will be.
- ThenAsNow 8y ago> the whole stratolaunch plan is predicated on developing a new air-launched rocket, and we just don't know what the specs on that will be Neither will Stratolaunch, any time soon: https://spacenews.com/stratolaunch-abandons-launch-vehicle-program/ https://spacenews.com/stratolaunch-abandons-launch-vehicle-p...
- floil 8y agoCan confirm. The whole group working on that effort has been laid off.
- deleted 8y ago[deleted]
- craftyguy 8y agoWhat an embarrassingly (for him) short sighted 'walk through'. Just having more capability to perform ariel launches will encourage companies to make vehicles. The likely reason nothing exists today is because there really aren't any options today..
- 8y ago
- adventured 8y agoI know there's a lot of skepticism about whether the plane has any likely long-term use and whether it can be successful commercially at all. I find it spellbinding to watch it fly. I'm so glad Paul Allen funded its creation.
- theseadroid 8y agoI wonder why this type of specific purpose airplane needs human in the cockpit? Why can't it be remote controlled?
- craftyguy 8y agoI suspect this huge, complex aircraft with it's very expensive, highly explosive cargo isn't as straight forward as flying a drone.
- klhugo 8y agoDoes anyone have a cost comparison between different launch systems?
- ourmandave 8y agoIf they're launching Pegasus XLs I wonder if they're on Northup Grumman's future acquisitions radar. Their competition, Virgin Orbit has it's own subsidiary Vox Space that makes the launch vehicle.
- tyingq 8y agoIt looks like intended rocket has changed a few times: https://en.wikipedia.org/wiki/Stratolaunch_Systems#Launch_rocket https://en.wikipedia.org/wiki/Stratolaunch_Systems#Launch_ro... But did eventually settle to the Pegasus XL: https://spacenews.com/stratolaunch-abandons-launch-vehicle-program/ https://spacenews.com/stratolaunch-abandons-launch-vehicle-p...
- avmich 8y agoThere are several advantages for airplanes as first stages. Less air drag on the higher altitude and more efficient engines, as they are optimized for smaller external air pressure. The speed of aircraft adds to the speed of the rocket. Another plus is that with aircraft you don't need to build a launch pad, the rocket is just released in mid-air. Yet another benefit is that aircraft can fly to a more preferable point for the launch - for example, the point where it is convenient to drop the first stage of the rocket, or the point closer to the equator so the satellite won't need to spend as much fuel to change the orbital plane. The airplane first stage can potentially fly to very different launch point, in many different countries, which can make logistics simpler. Those advantages all add up economically.
- duxup 8y agoI hadn't thought of the fixed launch pad situation. Do they expend a lot of energy / cost moving a satellite from where a fixed launch pad might easily place the satellite vs it's proffered orbit?
- myself248 8y agoMostly they have to pick their launch site so the flight path, headed into the right orbital plane, doesn't pass over populated areas. It would be rude to drop boosters and stages on people. https://history.nasa.gov/EP-165/p25.htm https://history.nasa.gov/EP-165/p25.htm
- m4rtink 8y agoWell, while possibly rude it still happens sometimes: https://www.extremetech.com/extreme/263732-china-keeps-dropping-expended-rocket-boosters-near-villages https://www.extremetech.com/extreme/263732-china-keeps-dropp... Will likely no longer be an issue once the new chinese spaceport in the south fully comes online.
- walrus01 8y agoInteresting fact, Israel is one of the few countries on earth that regularly launches into retrogade LEO (first stage flight path over ocean), because of the extreme political considerations around lobbing something that looks like an ICBM over their eastern neighbours. And the problem with dropping spent first stages on everywhere east of them.
- gaze 8y agoIsn't it amazing how you can tell a Burt Rutan design just by looking at it?
- deleted 8y ago[deleted]
- netman21 8y agoIs anyone looking at catapults yet? Seems that would be a great technology to pour billions into. Maybe that is why Musk is proposing Hyperloop? Get the engineering done for high speed trains, then scale it up. Way up. The Startram project estimated $60 billion for a catapult that could launch people. http://www.startram.com/ http://www.startram.com/
- jccalhoun 8y agoI know people have talked about this for a long time. There must be a logistical reason for it.
- DenisM 8y agoHow much acceleration can you endure? 3g is typical for a rocket launch, 9g is almost deadly. Accelerating to 6000mps at 3g will require 6000^2/(23g) = 600 kilometers of track, and it will take 200 seconds. That's a huge track, which has to be exactly linear or the payload will destroy it. Then there is also the fact that the payload will be exiting the catapult at the sea-level, thus facing the full atmosphere at 6000mps. Which is to say the payload will be instantly incinerated unless some kind of magic is invented akin to supercavitation. By contrast rockets do not even reach supersonic 300mps until 10k altitude, thus never encounter this sort of problem. Maybe you could build this 600km track thing in the Himalaya, but that much and that high in the mountains isn't going to be cheap. You can tell I though a lot about the same thing that you did. :)
- bufferoverflow 8y agoAs soon as we figure out how to build 100+ km tall structures.
- rdiddly 8y agoKind of a threadbare article. Not a word on why dual fuselages are desirable? Why it needs to have the world's longest wingspan? Like I'm supposed to just know all that from my aeronautics background? What if I flunked that course?
- asteli 8y agoYou need a large space open to attach the rocket to, and it has to be at the center of lift. You can't have one fuselage and put the rocket to the side, because then the balance would change drastically when you add the rocket, and you can't put the rocket under/in the fuselage because it's very large.
- rdiddly 8y agoThanks... it's the simple things!
- blunte 8y agoI hope that center wrong is unbelievably strong to handle the tortional forces that two separate horizontal stabilizers on lengthy lever arms might exhibit in acute turbulence.
- godson_drafty 8y agoThat flimsy tail design bothered me as well. Even if the center wing and wing roots are incredibly strong, there's little reason to place them under stresses that could be alleviated with a single-stabilizer tail design, as other commenters have pointed out. The fact that they did not do this suggests this aircraft is designed to launch millions in contributions into the designers' pockets, and not so much rockets into space.
- lstodd 8y agoI wonder how fast it would disintegrate in a case of asymmetric stabilizer runoff.
- deleted 8y ago[deleted]
- orbital-decay 8y agoI guess this thing has a pretty sophisticated control system to keep it stable, similar to modern combat aircraft. I also wonder if they have any fuel dumping procedures for an aborted launch; landing with a non-empty launch vehicle still on board seems quite scary.
- perilunar 8y agoWhy didn't they just mount the tailplanes higher and join them? (e.g. like the OV-10 Bronco tail)
- dredmorbius 8y agoI get the distinct impression Stratolaunch wasn't happy with the post-landing roll: https://youtube.com/watch?v=ZBj3FCdYS80 https://youtube.com/watch?v=ZBj3FCdYS80 (At 3m20s.)
- jdsully 8y agoI think its just fighting a bit of crosswind.
- ridgeguy 8y agoI agree. It was crabbed a few degrees to its left while aligned with the runway (3:24 - 3:33 in GP's video). That would indicate crosswind from the aircraft's left.
- dredmorbius 8y agoThe edit cut away immediately, to onlooker shots. It's an interesting flight phase, and pretty clearly one Stratolaunch did not care to feature. Several other onlookers did catch the roll, and the aircraft slewed markedly, with several cameramen commenting on this.
- m3at 8y agoAs cool as it looks, this airplane seems promised to go the way of the Hercules H4: fly once then stay in a museum forever. This recent podcast from mainenginecutoff speaks about Stratolaunch [1] [1] https://mainenginecutoff.com/podcast/108 https://mainenginecutoff.com/podcast/108
- bacon_waffle 8y agoI hope they take inspiration from these folks and do a simultaneous takeoff with a smaller plane, in opposite directions: https://youtu.be/R5P70XtI4zQ?t=39 https://youtu.be/R5P70XtI4zQ?t=39