Suborbital Spaceflight Update 153
HobbySpacer writes "Burt Rutan's group has fixed a problem with the SpaceShipOne and recently carried out a successful drop test. Ground studies involved tests with CFD - "creative Ford driving" using a Ford-250 pickup truck. Other suborbital news includes the announcement of plans to follow the X PRIZE competition with an annual X PRIZE Cup event in which rocket teams will compete in an air show type format. In Japan the RVT (Reusable Vehicle Test) just completed its third short hop (in Japanese) within a week. (English reports on the first and second flights.) The liquid hydrogen/liquid oxygen powered vehicle seeks to develop robust, reusable technologies for vertical takeoff and landing rockets. It and subsequent vehicles will gradually expand the flight envelope to high altitudes."
Gee, officer . . . (Score:2, Funny)
Interval technologies in use? (Score:3, Insightful)
Re:Interval technologies in use? (Score:1)
What is interval technology? Is it anything like interval training for athletes (i.e. number crunching really hard for short durations)?
Re:Interval technologies in use? (Score:3, Informative)
Re:Interval technologies in use? (Score:1)
Re:Interval technologies in use? (Score:1)
For the record, while real-time systems may be a while off, there are several companies offering good commercial modeling software that are built on these concepts. The reason they aren't widely known is that they are used mostly by heavy industries like minin
Re:Interval technologies in use? (Score:1)
Say you have an optimization problem that gives you too many solutions to evaluate with conventional numerical methods. Take for example an oil refinery that wishes to find the very best efficient and safe way of refining oil. There are many variables, equations, and nasty loop back cycles in this process. Traditional numerical analysis using floating point arithmetic will be struggling with errors carried over from each stage of the process, and will usually only find soluti
Re:Interval technologies in use? (Score:2)
Sub orbital flight (Score:1, Funny)
Re:Sub orbital flight (Score:3, Funny)
If, for instance, your ravine were on Phobos you could have gone orbital with pedaling (which again you didn't specify). Be careful though, escape velocity is only about 22.5 mph, although the high cadence the average BMX bike requires to achieve that sort of speed would protect just about everybody but track racers.
A very low orbit could be achieved at only several mph.
"Duck Timmy! Joey's coming 'round again."
KFG
Flying subs (Score:4, Funny)
Suborbital (Score:3, Interesting)
While I doubt this will happen, I'm just wondering what sort of margin for error exists.
Re:Suborbital (Score:2)
Re:Suborbital (Score:4, Interesting)
Re:Suborbital (Score:2)
BTW, your link was out of date. The closest I could find was this: http://www.dfrc.nasa.gov/Newsroom/FactSheets/FS-0
Re:Suborbital (Score:4, Interesting)
OOOh, I'm going to blow karma on a pedantry trip
Technically speaking, the only way to "Bounce off" the atmosphere is if you're coming in at greater than earth's escape velocity. If you're travelling slower than escape velocity, the best you can manage is a "loft" that trades height for speed. The golden rule here is: Once your non-interplanetary vehicle encounters the sensible atmosphere, your time in orbit is just about over.
The only vehicles for which "Bounce" was a serious problem were the Apollo capsules and Russia's Zond lunar spacecraft (which never flew manned). In the case of Apollo, "Skipping" was a serious consideration since although the trajectories ensured that even at lunar-reentry speeds, the atmosphere would be re-encountered, this could take 2-3 days on a looonggg orbit - a problem when the Command Module held power, fuel and other consumables for only 2-3 hours independent flight (having ditched the Service Module at this point). The re-entry programs and manual reversion procedures thus focussed on ensuring that a skip absolutely did not happen, at the expense of a hard ride down and loss of targetting, if necessary.
In the case of the X-15, however, the problems were different although related. Because the X-15 only got up to about Mach 6 (remembering that even low-earth orbit requires a speed of Mach 25), there was never any question of performing a significant "Bounce". Nevertheless, the conditions on an X-15 re-entry were severe enough that a Thermal Protection System (TPS) was required. Problem was, this was designed for the X-15's original target speed of Mach 5 and used a "heat-sink" inconel structure to absorb the heat whilst retaining strength. This worked just about OK, however when the X-15-A2 mods were made (external fuel tanks to increase deltaV hence re-entry speeds), this increase was enough to overload the TPS. The solution attempted was to spray a coating of (pink) ablative material over the X-15 before each flight, and let it burn off during re-entry. This proved problematic, not least of all because the charring ablative coated the pilot's windscreen! A more serious problem was caused by an experiment attached to the lower ventral fin, a mock-up of a hypersonic ramjet. At the increased speeds encountered by the X-15-A2, the shock waves from this ramjet impinged on the lower fin (rather than streaming past) and caused sufficient local heating to "eat" away the fin's structure.
Whilst it may be tempting to assign all of these problems to the "should have known better" category, remember that A) The X-15 was designed in the '50s. Using slide-rules and paper, and best judgement rather than fancy-dancy CFD codes and CAD/CAM. B) The X is important: it means that it's a vehicle designed to find out what the issues and problems are with a particular flight regime, and to test potential solutions.
SpaceShipOne's flight program is similar to the X-15 in many respects, but is lower-energy (Mach3 vs Mach5-7). They can expect to see greatly reduced heat load problems during their re-entry profile because of this, as well as having a novel way of dealing with it in a controlled fashion.
Re:Suborbital (Score:1)
Re:Suborbital (Score:1)
Re:Suborbital (Score:1)
Re:Suborbital (Score:3, Informative)
Re:Suborbital (Score:3, Informative)
Re:Suborbital (Score:2, Informative)
Re:Suborbital (Score:1)
There's probably a technical specification of re-entry, but a good working definition is "A manoever re-encountering significant aerodynamic effects occuring at hypersonic(ish) speeds". You'll note the fudge-factor on speed there.
To paraphrase this: It's not the height you get to, it's the speed at which you re-encounter the sensible atmosphere.
In the case of the X-prize contenders, they'll all pretty much have to "re-enter" the atmosphere even though they're sub-orbital: anything using a rocket to get to
Re:Suborbital (Score:1)
Not any more than you could floor the gas in your minivan merging onto the freeway and accidentally break the sound barrier. Low earth orbit needs a speed of 18000 mph or else you fall back to earth. These X-Prize entries aren't even close. Performance will be close to the X-15 rocket plane of the 60s. That set records of 4000 mph and 62 mi altitude (not on the same flight).
Re:Suborbital (Score:5, Informative)
Still, you do have to worry about re-entry heating, even at "only" Mach 3.5. Rutan's ship will have an ablative coating that sublimates away, carrying heat, for the hottest parts of the trip -- Rutan's ship needs this as it is made of composites that cannot tolerate even moderately high temperatures. This ablative coating would be applied every flight. The X-15 used a similar coating for its highest speed flights. As others note, the X-15 flight profile is very similar the profile for Rutan's SpaceShip 1.
The Armadillo aerospace vehicle uses aluminum, and is massive enough that there is enough of a heat sink that it won't get too hot for the short time there is significant aerodynamic heating.
thad
who tends to fund these projects? (Score:4, Interesting)
Re:who tends to fund these projects? (Score:3, Insightful)
Re:who tends to fund these projects? (Score:2, Informative)
Re:who tends to fund these projects? (Score:1)
Re:who tends to fund these projects? (Score:5, Informative)
As far as the Aerospce circles you run in not looking at Rutan's seriously what freaking circle is that. The man has done work for NASA, Northrop, and Boeing!!!
Has your group built anything that flys yet? Carries a useful load?
Rutan built a plane that carried two people around the world on one tank of gas. In most Aerospace circles his is the Man!!.
Re:who tends to fund these projects? (Score:1)
Re:who tends to fund these projects? (Score:2)
Since I am not in aerospace at all and I know
Re:who tends to fund these projects? (Score:1)
Re:who tends to fund these projects? (Score:3, Informative)
Note too that Rutan has been involved in space work before. The wing and tail surfaces of the Pegasus orbital launch vehicle are built by Rutan, as was the aeroshell of the DC-X vertical takeoff/landing test vehicle.
Rutan is also working on something called RASCAL, a grown-up version of the X-Prize system. It uses four lar
Re:who tends to fund these projects? (Score:1)
There is a bagel joke in here somewhere...
Its easy to get into space heres how. (Score:2, Funny)
2. Outfit him with a controlled reentry device (parachute)
3. Put him a lunch vehicle (catapult).
4. PROFIT.
Re:Its easy to get into space heres how. (Score:2, Funny)
if you do that he will exceed the weight limits quickly!
Re:Its easy to get into space heres how. (Score:2)
As an aside it is a truly weird feeling beeing 18 meters under the water & trying to convince your brain
Re: Its easy to get into space heres how (Score:1)
"airshow type format" (Score:2)
What could possibly go wrong with such a plan?
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Re:"airshow type format" (Score:2)
Re:"airshow type format" (Score:2)
Then how about we just say "NASCAR(tm)-type format" and be up-front about it?
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Re:"airshow type format" (Score:1)
Japanese space program (Score:2)
How would NASA handle this problem (Score:3, Insightful)
The F150 solution goes to show what the private sector can do, given the proper motivation.
Rutan is gonna win this thing on December 17th.
Re:How would NASA handle this problem (Score:2, Informative)
One of the early lifting body X-plane designs was tested by towing it behind a car like a glider...
Re:How would NASA handle this problem (Score:1, Interesting)
If you knew anything about the industry, you'd know that Rutan
doesn't know his aerospace from his arse.
Re:How would NASA handle this problem (Score:1)
That's why he's had one success after another, right?
Re:How would NASA handle this problem (Score:1)
And I DO know something about the industry.
Re:How would NASA handle this problem (Score:1)
Re:How would NASA handle this problem (Score:2)
The F150 solution goes to show what the private sector can do, given the proper motivation.
Sadly, people are still going to vote for socialized healthcare in 2004. Great, my next doctor visit will be managed by a NASA clone.
Sined, sealed, delivered. (Score:2, Funny)
Why am I having flashbacks to Buckaroo Bonzai?
Re:Sined, sealed, delivered. (Score:2)
I'll tell you later....
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Re:Sined, sealed, delivered. (Score:1)
Air show type event (Score:1)
I've seen this before somewhere (Score:5, Interesting)
I work for a competitor, but I've always regretted the DC-X getting its funding cut. It looked like it was a truly innovative idea and had a lot of promise.
Re:I've seen this before somewhere (Score:2)
It sure does.
I'm not in the aerospace industry, but I'm damn glad to see the DC-X concept getting a second shot at life.
Re:I've seen this before somewhere (Score:2)
I thought the DC-X was a neat technology demonstrator, and a catastrophically broken idea for a spacecraft.
Re:I've seen this before somewhere (Score:2)
Of course, the fuel for landing could be considered dead weight, too...
Disclaimer: IANARS (I am not a rocket scientist).
Re:I've seen this before somewhere (Score:2)
No diss, but I know a bit about this stuff. I hope that somebody who knows more than me can explain this to me.
Frankly, I don't think they can, because I think it's an attempt to be Flash Gordon rather than to make a good spaceship.
Re:I've seen this before somewhere (Score:1)
Re:I've seen this before somewhere (Score:2)
You're wrong too.
For every pound of fuel you want to use for landing, you need about four pounds of fuel to get that pound of landing fuel up into orbit. If I wanted to look at the orbital mechanics text that is two feet behind and one foot above my head, I could in about five minutes derive the actual fuel consumption curves based on estimated exhaust velocities of chemical rockets.
As with all aspects of aviation, material cost is not the primary factor. Weight is. This is far more true for roc
Re:I've seen this before somewhere (Score:1)
Re:I've seen this before somewhere (Score:1)
Re:I've seen this before somewhere (Score:2)
It is quite possible to use a different approach for a 30 foot height control test and a full re-entry.... you say you are a rocket scientist?
Perhaps it's time for a few lateral-thinking courses.
Me. the EVIL one.
Re:I've seen this before somewhere (Score:2)
You might do with some reading comprehension courses.
Re:I've seen this before somewhere (Score:2)
Plus, it's soooo Flash Gordon!
Re:I've seen this before somewhere (Score:2)
But then again, I can't really see how we're at the point where we need a universally usable vehicle. I think we're still inexperienced enough in space that we should be using vehicles that are custom designed for each mission, so even my above explanation doesn't really make a whole lot se
Re:I've seen this before somewhere (Score:2)
So, you're not the only person who can't see the point.
Re:I've seen this before somewhere (Score:2)
I worked with several PIs (principal investigators - heads of projects) while at NASA, and the truth is ugly. If it doesn't shine up real nice at the dog-and-pony show, it won't get th
Re:I've seen this before somewhere (Score:2)
Though, the Black Armadillo X Prize vehicle will use parachute recovery. I think that was because A) it's simpler and B) they were concerned about whether or not they would have the VTVL working on the big rocket in time. Maybe
Creative Ford Driving? (Score:2)
Re:Creative Ford Driving? (Score:1)
Fix Or Repair Daily
Failed On Race Day
F'd Over, Rebuilt Dodge
Re:Creative Ford Driving? (Score:1)
Found On Road Dead
Fold Over Read Directions
F'er Only Rolls Downhill
Re:Creative Ford Driving? (Score:2)
First On Race Day
Re:Creative Ford Driving? (Score:2)
Then again, maybe you're right... = )
Re:Creative Ford Driving? (Score:2)
Farked On Race Day
Oh, come on..... (Score:1, Funny)
Note: http://www.imdb.com/title/tt0082509/
That's nothing... (Score:2)
I think I could see my house from up there.
I love the japanese ship... (Score:1)
i like this guy... (Score:3, Insightful)
Burt Rutan is such a great idol figure for any aspiring youth; he's cool as elvis, no nonsense as any good ol' american commonsenser, creative as da vinci and alternative as it can be yet deeply respected and admired by the "establishment" guys of his craft. The fact that he can make a design company as relatively small as his sustain itself and succeed in a market that is dominated by huge corporations that not only are deep pocketed and heavily staffed but also capable of yielding political influence, such as boing and lockhead martin, and just do his thing yet sell good without "selling out" is phenomenal and very inspiring. His design are truly creative and beautiful. It's a testament to a design when it's not only highly functional but also beautiful, and wild in a way that's unlike any before yet amazingly simple and makes sense in a way that makes you think there's no good reason why it shouldn't have been this way all along. He should a case study on the list of everyone who's even remotely interested in innovation.
NASCAR = IAMRAD (Score:5, Interesting)
Rather than a 1/4 mile horizontal drag race, make it ia 1 mile vertical drag race with total flight staying within the limits of Class E airspace, preferably below 14,500 ft [esva.net].
Start with the Rocket Guy's 15,000 ft flight as a standard [slashdot.org] and do exhibitions involving dual launches of these vehicles. Grandstands must of course be at a safe distance but you don't need to be too close to something like this for the thrill of your life. There's a lot more energy being released in these drags than a typical 1/4 mile drag of course, and a lot higher likelihood of fatalities to the "drivers" but if you move it out to a remote area you can have some serious fun while developing the flight systems needed to carry men to orbit.
I like the X-Prize and all but really there needs to be some serious motor-head madness here with the motor babes [crash.net] and all.
A side benefit of this sort of competition is we get to find out if the spam in a can idea of manned rocketry is actually superior to human guidance. We all know someone will just have to attempt human guided rockets.
CFD - now I get it! (Score:2)
more RVT (Score:1)
Re:CFD, for the curious (Score:2)
Re:CFD, for the curious (Score:2)
Re:CFD, for the curious (Score:4, Informative)
Not to nitpick here, but 'Fluid' is not misleading at all. The common definition of a fluid is a substance that will take the shape of its container. Both liquids and gasses will do this.
Re:CFD, for the curious (Score:1)
Re:CFD, for the curious (Score:1)
Preventing fluid escape as you fill the container is an exercise left to the reader.
Re:CFD, for the curious (Score:1)
Re:CFD, for the curious (Score:1)
Surface tension is a very not strong force. A litre of water masses what, a kilo? Surface tension force in water is (if I remember correctly) teeny fractions of a newton per unit length, which must be integrated over the surface, blah blah math happens now, but you don't have much F to do MA.
So, forming that sphere is not going to be easy.
Re:CFD, for the curious (Score:2)
Re:CFD, for the curious (Score:5, Interesting)
To build a wind tunnel to test a full-scale airplane would cost tens of millions of dollars. The tunnels at Nasa Ames in Mountain View have been shut down because it's too expensive to run them -- to run the fans in the 120x80 tunnel took more than 100 megawatts.
On the other hand, driving a truck down the runway will generate the same windspeeds over the airplane using about 100 horsepower or about 75 kilowatts, more than 1000 times as efficient.
Burt's early van-based systems for testing the VariEze used very cute aerodynamic balances to measure the forces on the airplane models. In pictures I've seen he had a model on one side of a pivot, and a circular disk on the other side. The circular disk generates a known amount of drag, and by moving it closer and further from the pivot will show how much drag/lift/whatever the model was generating.
Disclaimer -- I tried but failed to name my son Elbert.
thad
Re:CFD, for the curious (Score:2)
Maybe, but you can't achieve very high speeds with this. Maybe you don't need to have such high speeds, but something about a suborbital flight suggests to me that high speeds are important.
Now the Avro company (who made the unfortunatlly scraped Avro Arrow), launched scaled down models on rockets. Of course, maybe this is harder to monitor than using a truck. On the other hand, you get much higher speeds and it is also super cheap.
Re:CFD, for the curious (Score:1)
Gosh, maybe this Rutan guy knows what the fuck he's doing, huh?
Re:CFD, for the curious (Score:2)
Do you *try* to sound snotty? Or is that just your natural charm? Did you see me say that Rutan was an idiot in my post? No. So quite being condecending.
Re:CFD, for the curious (Score:1)
Re:CFD, for the curious (Score:2, Informative)
Others have pointed out that gasses are fluids. To further pop the gas-liquid-fluid misconception, aerodynamics students are first taught low-mach flows, where the dynamics of gasses and liquids are very similar. This is why it isn't uncommon to see water tunnels in aero labs.
Re:CFD, for the curious (Score:2)
As in the same people that will say we 'breathe in oxygen', when the better part of the air we breathe tends to be nitrogen.
*tattoos on his forehead that this is a scientifically-inclined site*
Re:CFD, for the curious (Score:1)
So you're wrong. Sorry.