Paul Allen's Stratolaunch Finally Flies The World's Biggest Plane (geekwire.com) 69
"Stratolaunch, the aerospace venture founded by the late Microsoft co-founder Paul Allen, sent the world's biggest airplane into the air today for its first flight test," report GeekWire.
The twin-fuselage plane, which incorporates parts from two Boeing 747 jumbo jets and has a world-record wingspan of 385 feet, took off from Mojave Air and Space Port in California for a flight that lasted two and a half hours. For more than seven years, Stratolaunch has been working with Mojave-based Scaled Composites on the project, which aims to use the plane as a flying launch pad for orbital-class rockets. The first flight test had been anticipated for months. "We finally did it," Stratolaunch CEO Jean Floyd said today during a briefing.
Stratolaunch's plane, which has been nicknamed Roc after a giant mythical bird, took off at 6:58 a.m. PT and went through a series of in-flight maneuvers, including roll doublets, yawing maneuvers, pushovers and pull-ups, steady heading side slips and simulated landing approach exercises. Stratolaunch said it reached a maximum speed of 189 mph and maximum altitude of 17,000 feet.... The plan ahead calls for further tests over the next 12 to 18 months, with the aim of getting the plane fully certified by the Federal Aviation Administration. Stratolaunch has already struck a deal to use Northrop Grumman's Pegasus XL rocket to send payloads weighing as much as 816 pounds (370 kilograms) to low Earth orbit...
Stratolaunch's air-launch system is designed to carry multiple rockets up to an altitude of about 40,000 feet, and then drop them into the air to fire up their rocket engines. The advantage of such a system is that it can take off from any runway that's long enough to accommodate the plane, fly around bad weather if need be, and launch a satellite into any orbital inclination.
Stratolaunch CEO Jean Floyd said their team had dedicated the flight to Paul Allen.
"[A]s the plane lifted gracefully from the runway, I did whisper a 'thank you' to Paul for allowing me to be part of this remarkable achievement."
Stratolaunch's plane, which has been nicknamed Roc after a giant mythical bird, took off at 6:58 a.m. PT and went through a series of in-flight maneuvers, including roll doublets, yawing maneuvers, pushovers and pull-ups, steady heading side slips and simulated landing approach exercises. Stratolaunch said it reached a maximum speed of 189 mph and maximum altitude of 17,000 feet.... The plan ahead calls for further tests over the next 12 to 18 months, with the aim of getting the plane fully certified by the Federal Aviation Administration. Stratolaunch has already struck a deal to use Northrop Grumman's Pegasus XL rocket to send payloads weighing as much as 816 pounds (370 kilograms) to low Earth orbit...
Stratolaunch's air-launch system is designed to carry multiple rockets up to an altitude of about 40,000 feet, and then drop them into the air to fire up their rocket engines. The advantage of such a system is that it can take off from any runway that's long enough to accommodate the plane, fly around bad weather if need be, and launch a satellite into any orbital inclination.
Stratolaunch CEO Jean Floyd said their team had dedicated the flight to Paul Allen.
"[A]s the plane lifted gracefully from the runway, I did whisper a 'thank you' to Paul for allowing me to be part of this remarkable achievement."
Air launch of rockets (Score:5, Informative)
Launching rockets from airplanes has been done before but the plan with Stratolaunch is to do so on a larger scale with functionally a bigger rocket. There are some advantages and some disadvantages. One major disadvantage is that there's functionally a size limit: one cannot really put that large a rocket on a plane (and the fact that to get this to work they need to use what is by multiple metrics the largest airplane ever reflects that).
The plane is functioning to some extent like a reusable first stage, but a plane isn't likely to go as high or as fast as as a true first stage, like the Falcon 9's first stage, so it isn't the same as having a true reusable first stage in terms of power.
At the same time, a plane is a well understood, reliable technology. Another connected advantage of air launch is that one is much less beholden to weather events. since the plane can fly above or around bad weather. The Falcon 9 in contrast frequently needs to be delayed due to weather issues (which are made worse in its case because it is a very long and thin rocket); one does have things like the Soyuz which is able to launch in functionally blizzard conditions, but that's pretty rare for a rocket and is in a large part due to the fact that it was originally designed to be an ICBM.
Re:Air launch of rockets (Score:5, Interesting)
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I do have to wonder how much of the advantage this initially had on the drawing board has since been wiped away by the SpaceX reusable first stage. Watching those two rockets land in robotic synchrony the other day... wow.
Very little I imagine. So far the Falcon 9 has at best seen a 5 month refit before it can be reused again. Even if they do get to their stated goal of a 24 hour turnaround, it will never be that. In a best case scenario, a Falcon 9 will land on a robot barge, take several days to a week to return to port, take massive cranes to lift and move back to the factory, refit in 24 hours, and then get prepped for launch again. That's a lot of logistics.
A plane option on the other hand could land, reload, and la
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A plane option on the other hand could land, reload, and launch same day, and require basically refueling, no massive retrofit.
Yes, I can't wait to watch it launch once a year for about two years before they never fly it again.
That's a possible scenario, but at this stage, it is too early to tell. This is just Alpha (though a very impressive Alpha). There's a shitload of factors, many of them non-technical that will determine if this approach takes off (no pun intended) or not.
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Not that strange - Navy aircraft land tail first. 8-D
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Where's the fucking landing video?
That's what I wondered. From the link :-
Observers said the plane appeared to swerve a bit on the runway during its landing, and Thomas confirmed that there were “a couple of corrections to line up in the slowdown.”
The video, which is constantly interrupted by annoying hype captions, give some good shots of take-off but the view of the landing is mainly obscured by spectators' heads. That makes me suspicious. There is no end-on view (like there is for take-off) to show this swerving.
Even before I read about the swerving, it seemed to me that landing could be a problem with widely spaced wheels, as one side can touch down significantly earlier than the other, leading to dynamic
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Launching rockets from airplanes has been done before
It's actually been done for decades, the main differences being that they were pointed down rather than up and they carried warheads rather than payloads.
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https://en.m.wikipedia.org/wik... [wikipedia.org]
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The recent Falcon Heavy launch was delayed a day due to upper level winds -- windshear can cause a long, skinny tube like the Falcon to crumple/snap. Flying above clouds does nothing to avoid this, although the max altitude of the Stratolaunch should put a rocket just above these, assuming it can actually reach that.
OTOH, planes have air-breathing engines that run on relatively cheaper fuel, so have a higher ISP and lower cost/KG. The real question is how heavy of rockets it can carry and if it'd end up bei
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Flying above clouds does nothing to avoid this
I think the idea is that you fly the aircraft and its payload somewhere that there wont be high level winds on the day you want to launch.
Although at 189mph that could take a day or two all by itself.
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The new SpaceX rocket design can handle much stronger winds because of its increased diameter, so this is a problem than can be solved.
Of course, the worst that happens with an F9 launch is that it's delayed by a few days until the weather clears up. Compared to the rest of the schedule, that's not too bad.
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"Launching rockets from airplanes has been done before but the plan with Stratolaunch is to do so on a larger scale with functionally a bigger rocket. There are some advantages and some disadvantages. One major disadvantage is that there's functionally a size limit:"
In the best case, it's just a self-landing reusable 1. stage and lately, the world has noticed that this reusability feature is already built-in in the rockets of their competitors.
But perhaps they could be used to deliver SpaceX rockets to whoe
World's biggest plane? (Score:1)
It's only the world's biggest plane in terms of wingspan. In terms of weight, payload, or length, Soviet An-225 remains the biggest.
Any orbit, any time... (Score:5, Insightful)
To me, the most interesting aspect of Stratolaunch is the flexibility enabled by positioning your "launch pad" at just the right place. But I don't know if that will be enough to sustain them in the current market. A lot has changed since they started working on this project, with SpaceX and Rocket Lab both providing "budget" launch services, not to mention Blue Origin waiting in the wings. It will be interesting to see how/if they manage to find their niche.
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Well, I doubt that that ability will really come to fruition, given that the carrier aircraft only has a range of 1,200 nautical miles, and the entire launch stack will require a huge support base to operate from any given site in the world - and on top of that, you need airspace closed to allow this thing to launch a rocket, so that requires a lot of notice.
In reality, this thing will fly from one or two air fields, with launches planned well in advance.
That's if this this thing will actually do any commer
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Its my belief that Stratolaunch may fly once or twice more, and then will be shipped to a museum somewhere, or sold for scrap. Given the rise of micro-launchers around the world these days, maintaining an expensive aircraft isn't as viable as it once was.
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Stratolaunch has no advantage over Stargazer in that respect, and they've been trying to get ICON launched on a Pegasus since December of 2017. The "any time" advantage has not materialized in real world operations. Relying on a one-of-a-kind custom-built giant aircraft is not going to help any.
Re:What's with the dual fuselages? (Score:4, Informative)
The original plan was to sling huge rockets in the middle, but the rockets are cancelled and so they're only launching the tiny Pegasus rockets now [spacenews.com]
Brings all new meaning to left seat/right seat (Score:2)
Joking aside, that has to be a weird feeling for the pilots to be so far away from the centerline of the plane. Not that you're going to fly anything this (amazingly, incredibly) massive by the seat of your pants anyway, but still.
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I dunno... whenever I see that plane, I just think how it seemingly easy it would be to snap it in half. Just landing the thing must be an adventure.
Sadly a dead end (Score:3, Informative)
This is a spectacular piece of aerospace engineering, basically a huge flying wing built to lift several hundred ton boosters.
The recent SpaceX Falcon 9 Heavy launch with full booster recovery destroys the economic advantage of air launch.
SpaceX's success indicates that launching can become a refuel and repeat process, so there is no need for a hugely expensive aircraft launch vehicle. Especially as that aircraft has limited speed and range and requires an enormous runway to operate from, which undercuts the idea that it can launch to any azimuth from anywhere.
From a business perspective, the operation was successful, but the patient died. Sad.
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Air launch itself isn’t a dead end, the benefits of launch flexibility could be material. The lack of a competitive advantage over the current launch platform for the rocket gets me though.
Really seems like they need a bigger (or smaller/cheaper) air launch rocket to have material advantages.
Air Launch has no economic advantage (Score:2)
The amount of energy you gain from air launching is a tiny fraction of what's required to get the payload into orbit. Optimistically assuming air launch at 40k' (12k metres) and 600mph (270 metres per second), the energy of 2.2lb (1kg) of payload at launch is approximately 275 kJ but to achieve a 100 mile (160 km) orbit travelling at 17,500 mph (7,800 metres per second) 32 Megajoules of energy is required for the payload. Interestingly enough, I did a quick check of my math and found out that the 32 MJ re
Re:Air Launch has no economic advantage (Score:5, Informative)
the energy of 2.2lb (1kg) of payload at launch is approximately 275 kJ but to
Sorry, but you are doing the wrong maths. Rockets are not like cars, the important metric is delta-V, not energy.
Calculating kinetic energy to achieve orbit is a rookie error. - unless you happen to have a giant rail gun or space elevator.
This is why rocket "power" is always quoted in Newtons, not Watts.
Take a look at the Rocket Equation: https://en.wikipedia.org/wiki/... [wikipedia.org]
The maths is just simple algebra, no calculus needed - have fun!
Neither "energy" nor delta-V ( velocity/momentum) are the reason for air launch though.
It avoids problems of getting through the low, dense atmosphere, and you can have a more efficient rocket if it only has to operate in thinner air.
But Elon Musk stated that the total benefit amounted to 5% payload increase, so they scrapped the idea. Its easier to just build a 5% bigger rocket.
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That's not what I heard.
https://vimeo.com/13497928 [vimeo.com]
What is the benefit? (Score:2)
The Pegasus XL is currently launched (singularly) from an L1011; honest question, but what benefit does Stratolaunch hav over Orbital besides “we can carry three?”
Re:What is the benefit? (Score:5, Informative)
The real problem is that Stratolaunh was designed with a much larger SpaceX rocket [wikipedia.org] in mind that got cancelled. So the 3x Pegasus is a fallback plan.
Considering how rarely Pegasus launches (43 launches in 29 years), it doesn't seem like a wining proposition.
Stratolaunch can probably fly higher than the L1011, which would give Pegasus new mission options it did not have before.
The Pegasus L1011 is the last L1011 flying in the world, so it would be a shame to see it be retired, but I suppose that is the lifecycle of aircraft.
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Correction: there is one other TriStar still flying.
http://tristarexperience.org/ [tristarexperience.org]
Advantages of air launch (Score:5, Informative)
Next you don't have to push through 40,000 feet of atmosphere. Rockets launched from sea level do not accelerate at their maximum rate because they want to reduce loss due to air resistance.
Third is flexibility of launch location. You can now launch from anywhere your plane can get to. Launching from the equator to geostationary orbit is easier than going form south Florida.
Last you start a little higher and with an initial velocity. This is probably the least advantage but it still counts. Rockets are all about change in velocity and its an exponential equation. Want to go an extra 1500m/s double the size of your rocket. So a little initial altitude and velocity can mean a huge difference in the amount of fuel needed to reach your intended orbit.
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See my previous comment.
It seems like air launch should be a superior method of launching but the math and the practicalities don't come together for it to work.
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" You can now launch from anywhere your plane can get to."
Well not really - you'll still need a lot of the support infrastructure for the rocket, eg fueling etc, even if you don't need an actual pad. Plus with a large rocket strapped beneath I imagine the take off run for that aircraft possibly runs into miles so a huge runway is needed. In the end I suspect it'll only be launched from where current rockets are launched from anyway.
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I also wonder how well that huge thing will do when taking off or landing in bad weather.
Anyone know how they'll aim the rocket? (Score:3)
In my (admittedly layman's) understanding, one nice thing about launching from the ground is that you can keep your rocket aimed precisely straight-up at the moment of ignition (and hopefully thereafter as well, until it's time to deliberately modify the rocket's attitude).
Having the rocket strapped to (and then released from) an aircraft, on the other hand, introduces the possibility that when the rocket's engines ignite, the rocket will be pointing in some inappropriate direction and won't be able to re-orient itself "in time" (for whatever definition of "in time" applies in order for it to make it to its intended orbit).
Does anyone know the technique they plan to use to make sure their rockets are pointed in the right direction when they start producing thrust?
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Here is one option: After the rocket is dropped you deploy parachutes attached to the top. Once the rocket points upward you jettison the chutes and fire the rocket. This has been demonstrated before. See https://www.youtube.com/watch?... [youtube.com] .
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Ground-launched space rockets begin to roll to the optimal attitude and pitch over to let gravity help pull the rocket horizontal basically the instant they are clear of any launch infrastructure. Getting out of the atmosphere is easy - it's horizontal velocity that keeps you out, and you need a whole hell of a lot of it.
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How well does it land in crosswinds? (Score:3)
When an airplane lands in crosswinds (i.e. wind direction is not parallel to the runway) its nose is pointed at an angle to the runway. When it touches down, the plane needs to abruptly swivel so the nose is pointed down the runway, as now it is being directed by wheels rather than wind. In strong crosswinds, this operation looks really freaky. Here [youtube.com] are crosswind landing videos.
Here we have a plane with landing gear much much further apart than any ordinary plane. I wonder whether this makes it harder to do that abrupt swivel? If so, the plane will have much greater restrictions on crosswind landings.
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When it touches down, the plane needs to abruptly swivel so the nose is pointed down the runway, as now it is being directed by wheels rather than wind.
Unless it's a B-52. ;-) Your point is still valid, of course.
Flight video (Score:3)
For those wanting the unadulterated experience, including the slightly oddways landing.
https://www.youtube.com/watch?... [youtube.com]
Surprised they didn't use an exisdting bomber (Score:2)
Air launch has a lot of advantages - the lower air density allows smaller rockets to be efficient (less air drag, square / cube law), lower exhaust pressure (higher ISP, or lower chamber pressure), etc. Also allows a wide choice of launch sites and orbit inclinations. and avoids most of the weather. So I see the advantage.
I'm surprised though that they didn't use a conventional bomber that is designed to release large objects at high altitude. I'd think it would be possible to get a surplus de-militariz
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I remember reading, some years ago, about how some Russian company was going to buy up surplus Backfire [wikipedia.org] bombers and convert an air-launched cruise missile into something which could take small payloads to orbit. The idea was to use the old, supersonic bomber as a reusable first stage and the cruise missile (rocket-powered, not jet-powered) as a second stage, with a supers
Comrade. (Score:2)
This thing really does look like something the Soviets would build. Or try to build.