Will there be orbital "space planes" in the near future?

[frodo1008]

Yes indeed structural strength would be an issue, but not the only one. Think about how large a 1,000 ton aircraft would be! Where on Earth would you even find airports to land such a creation? Many international airports are even having to make somewhat expensive modifications for the Airbus A380, and that would be far smaller than such a craft!<br /><br />The only time I have ever seen even futuristic pictures and plans for aircraft even approaching this size was a number of years ago in Popular Science or some such publication. These aircraft were to be giant seaplanes proposed by the Japanese, and being a series of land poor Islands, such seaplanes would make very good sense to the Japanese. They would have had at the very least some 10 or 12 very powerful jet engines mounted on the top of the wings to avoid water problems. They were indeed in the class of small cruise ships at some 1,000 tons or even more. I would guess that the incredible expense of actuallly designing and building such behemouths doomed the idea to nothing more that a paper study at best. Too bad, in a way, it would sure have been interesting to have seen them fly!!

 

[mrmorris]

<font color="yellow">"'Space Plane' lifting bodies, like the proposed Venture Star or the NASP did not rely on parachutes to land."</font><br /><br />SSTO craft which are also lifting bodies are indeed a special case. The difficulty with them is getting them <b>up</b> rather than getting them <b>down</b>. The interior volume of the Venturestar and the NASP would have been largely filled with propellant tanks. Coming down, they would have been empty and the sucker would have have been extremely light for the lifting area.<br /><br />VT_H was sort of mixing things up, talking about both spaceplanes (which may or may not be SSTO) *and* about lifting-body based re-entry vehicles. A re-entry or TSTO vehicle that is based on a lifting body will have to support <b>much</b> more weight for a given area of lifting surface than an SSTO craft which is a LB. It will therefore have a significantly faster drop rate. You cannot compare a capsule to an SSTO lifting-body, it's an apples to orangutans matchup. My comments are in relation to capsule-based RVs to lifting-body based RVs.<br /><br />I'm well aware that won't change your mind on the subject, but then I've decided that the only possible way to change <b>your</b> mind requires the services of a humpbacked gentleman by the name of Igor and his trusty hacksaw.

 

[spacefire]

neah, beautiful women can make me change my mind as well.<br />Anyways, see the HL42 or HL20. they're two stage designs that don't rely on parachutes for landing-hence the HL designation which stands for horizontal landing. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[mrmorris]

<font color="yellow">"Anyways, see the HL42 or HL20."</font><br /><br />Ayup. When the STS was at the same stage of existence, it was going to launch once every nine days and cost $25 million/flight. <br /><br />Now pull the other one.

 

[nacnud]

I am not an aerospace engineer but the 1000 tonne aeroplane may be feasible. From what I have read the wings on the A380 are capable of carrying 750 tonnes without modification. Also the only modifications needed to airports to accommodate the A380 are for the passenger embarkation ramps. The A380 can land anywhere a B747 can.<br /><br />That said I prefer the spaceX approach to CATS, simply because I think the smaller initial investment means that the project is much more likely to get a vehicle flying before the development cash runs out.<br /><br />A possible development of the A380, the A20.30 although the only reference to it I can find is here.<br />

 

[halman]

Syndroma,<br /><br />Airplanes have to land somewhere, and airplanes that are very large are very heavy, but have very few tires to distribute that weight on the ground. (I think that the very few tires thing has something to do with control when landing and taking off, but I am not sure.) The Airebus 380 will require that taxiways, runways, and aprons all be strengthened at most airports, because the bird puts so much weight in small areas.<br /><br />So building huge airplanes is prohibited by airport capabilities, as well as drag. The bigger the plane, the more drag it is going to encounter. A carrier wing can put up with drag for couple of hours, but a 747 on a 14 hour flight needs to avoid it.<br /><br />Structural strength is not really an issue, as the wing is supported over the entire bottom surface. And it doesn't have to be rigid, as anyone who has ever watched the wings of an airliner in flight knows.<br /><br />Consider supertankers. These monsters can run up to nearly 1/4 of a mile long, and take several miles to stop. No one would have dreamed of building such ships until there was a pronounced demand for that kind of hauling capacity, and an infrastructure which allows such vessels to load cargo while still in deep water.<br /><br />We have never seen a plane with a 600 foot wingspan before because no one has needed to build one before, not because it can not be done. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[nibb31]

Excuse me for intruding. I've been lurking on this board for a while. I happen to live in Toulouse, France where the A380 is being built and tested. I'm lucky enough to see it in flight quite regularly.<br /><br />What you state about reinforcing runways for the A380 is incorrect. The plane was designed to require minimal work on airports. The only work that may have to be done at some locations is to widen taxiway clearance to make way for the wingspan of the aircraft, and more prosaically, increasing terminal facilities (waiting rooms, corridors, toilets...) to cope with 900+ passengers. <br /><br />Other than that, is an airport can cope with a 747 or A340, then it can handle the A380.<br /><br />There is no work required on aprons or tarmac, because the plane is designed to land very gently and has no less than 22 wheels. The weight is spread out as much as possible. If you have seen any videos of the test flights, you will also notice that it takes off and lands much shorter than a 747.<br />

 

[henryhallam]

<font color="yellow">If you have seen any videos of the test flights, you will also notice that it takes off and lands much shorter than a 747.</font><br /><br />Were the test flights done with ballast simulating the FULL weight of pax, fuel and cargo? If so then it must have some pretty powerful engines...

 

[gunsandrockets]

Airlaunch<br /><br />t/Space seems to have done a lot of thinking about the needs of airlaunched orbital rockets and the design requirements of the Very Large Aircraft needed to do the job. Your [halman] catapult launched aircraft with top mounted rocket may have some performance advantages over the t/Space system, but it seems to me the t/Space VLA is a lot simpler, easier to develop and more operationally flexible than your concept.

 

[gunsandrockets]

"As a general rule, lifting bodies designed for space use require chutes too. Their drop rate is too fast for a landing otherwise [with conventional landing gear]... unless you add wings, which adds mass and reduces payload. "<br /><br />And what is your supporting evidence for your claim?<br /><br />And how do you account for the X-24a and X-24b lifting body programs which land with conventional landing gear and without the use of wings?

 

[mrmorris]

<font color="yellow">"And how do you account for the X-24a and X-24b lifting body programs"</font><br /><br /><i>"...lifting bodies designed for space use..."</i><br /><br />Which of these words do you require a definition for?

 

[nacnud]

How much did the X-24a and X-24b weight? Is that the same as for a craft returning from space? What was the landing speed and is that a practical speed to land at? Would the craft need to be piloted manually?<br /><br />I’ll google myself once I’m off work but you might know the answers already.<br />

 

[gunsandrockets]

"mrnorris is correct. The lifting bodies including the HL-42 were found to be too dangerious to lad on a run way due to the excessive descent rate."<br /><br />That does not track with what I have seen about the X-24b program.<br /><br /> <br /><br />"I have a copy of a memo by John Young that states that anythin less that the Space Shuttle L/D was un acceptable. In fact he did not think the Shuttle Orbiter L/D of 6:1 was quite safe enough. At the very least he said that was the lower limit.hor"<br /><br />The X-15 safely landed with only a 4 to 1 ratio.

 

[gunsandrockets]

http://66.102.7.104/search?q=cache:xbH8szv7F7wJ:www.dfrc.nasa.gov/DTRS/1999/PDF/H-2287.pdf+x-15+lift+to+drag&hl=en&ie=UTF-8<br /><br />"...Fundamental<br />studies by the NACA<br />§<br />and NASA in the late 1950’s and<br />early 1960’s described three basic methods of<br />atmospheric reentry: ballistic reentry, winged reentry,<br />and wingless lifting-body reentry. The ballistic reentry<br />approach necessitates the use of parachutes to land, but<br />the lifting body and wing-body approaches provide the<br />possibility of horizontal landings..."<br /><br />"...In addition, most lifting reentry<br />configurations are attractive from the standpoint of<br />volumetric efficiency, crossrange and downrange<br />capability, peak acceleration and heating rates, and low-<br />speed handling qualities..."<br /><br />"...The vehicles examined in this paper, the M2-F1,<br />M2-F2, HL-10, X-24A, X-24B, and X-15 vehicles and<br />the Shuttle prototype, comprise a unique class of<br />aircraft. Not only were the vehicles all lifting reentry shapes, they were all piloted and capable of routine unpowered horizontal landings..."<br /><br /><br /><br />"...The first lifting-body concepts involved very blunt<br />half-cones.<br />3, 5 <br />Later, the concepts evolved into higher-<br />fineness-ratio cones,<br />6–8<br />and the capability of achieving<br />conventional (although unpowered) horizontal landings<br />was discussed. Numerous wind-tunnel model tests were<br />performed on candidate versions of the half-cone and<br />shapes having flattened bottom surfaces. In 1962, Reed<br />demonstrated unpowered horizontal landings and<br />controllable flight with a miniature lightweight radio-<br />controlled model of an M2 half-cone configuration.<br />9<br />This demonstration was followed by the construction of<br />a lightweight M2 craft large enou

 

[gunsandrockets]

"...lifting bodies designed for space use..."<br /><br />I see, so you are claiming the X-24 was NOT a reentry vehicle shape? I suppose the whole X-24 program was just for hotdogging pilots to show off? Get serious.<br />

 

[mrmorris]

<font color="yellow">"I see, so you are claiming the X-24 was NOT a reentry vehicle shape? "</font><br /><br />No -- I'm talking about the same thing nacnud already alluded to -- spacecraft and aircraft are different animals. A craft designed for space is going to be heavier for a given size than an aircraft due to additional equipment, heat shielding, etc. Aircraft can have lots of empty space inside the airframe -- spacecraft must cram equipment into every nook & cranny -- making them denser. That extra weight/density is going to translate to a steeper descent.

 

[syndroma]

Look at the picture. This is the landing gear for 600 tonnes plane (An-225).<br /><br />If you proceed increasing weight of the plane, at some point there will be no place beneath to install additional wheels. What to use then? Tracks?

 

[gunsandrockets]

And so we come full circle.<br /><br />Again. Other than your personal say so, what is your supporting evidence that a lifting body reentry module must use parachutes to land? What is your evidence that a lifting body cannot land using conventional landing gear? How do you explain the X-24 program?

 

[mrmorris]

<font color="yellow">"...what is your supporting evidence that a lifting body reentry module must use parachutes to land? "</font><br /><br />Get your facts right, I said 'As a general rule', not 'must'.<br /><br />My supporting evidence would be that lifting body based re-entry vehicles being designed today have them... as a general rule. The closest a lifting-body re-entry vehicle ever got to being 'real' was the X-38 -- which required a parafoil for landing. At that -- it was a very cut-down craft, with very limited on-orbit capability, <i>and the parafoil was over 12% of the landing mass of the craft</i>. The Lockheed CEV concept -- being touted primarily as being better than a capsule -- uses a parachute. LockMart wants to differentiate that craft from a capsule in every way they can. If it were feasible to land it without the parachute, they would.<br /><br />If you'd like to dispute that this is a general rule, please present three re-entry vehicle concepts developed in the past fifteen years or so which do <b>not</b> require the use of parachutes on landing.<br /><br /><font color="yellow">"How do you explain the X-24 program? "</font><br /><br />I explain it as a test in aeronautics. It might shock you -- but there have been a <b>lot</b> of different shapes, wing combinations, etc. that have been built and flown for testing of this nature and... don't tell anyone, but not all of them actually went into production, even when the testing was listed as a success.

 

[spacefire]

MM, besides the X24 there were the HL-10 and M2F2 and X24B...all of them landing on a runway.<br />Granted, they probably were lighter than a spacecraft would be on landing, but that means only that the landing speeds of said spacecraft would be higher.<br />Not a significant penalty to pay for the benefits you would get from a runway landing(better turn-around time) and lower G forces offered by a lifting body configuration. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[gunsandrockets]

"I explain it [X-24] as a test in aeronautics."<br /><br /><br />Here is a link about the NASA lifting body "aeronautics" program!<br /><br /><br />http://www.nasa.gov/centers/dryden/news/FactSheets/FS-011-DFRC.html <br /><br /><br />Note in particular this statement..."These lifting bodies were basically designed so they could fly back to Earth from space and be landed like an aircraft at a pre-determined site. " <br /><br />Hmmm...sounds like a space program to me. If the lifting body program was really just an "aeronautics" project maybe mrmorris can tell us about the mystery aircraft the lifting body program was designed to support?

 

[gunsandrockets]

"My supporting evidence would be that lifting body based re-entry vehicles being designed today have them... as a general rule. The closest a lifting-body re-entry vehicle ever got to being 'real' was the X-38 -- which required a parafoil for landing. At that -- it was a very cut-down craft, with very limited on-orbit capability, and the parafoil was over 12% of the landing mass of the craft. The Lockheed CEV concept -- being touted primarily as being better than a capsule -- uses a parachute. LockMart wants to differentiate that craft from a capsule in every way they can. If it were feasible to land it without the parachute, they would. "<br /><br />Pretty thin and about what I expected.<br /><br />The Lockheed CEV only has an l/d of 1.0, the purpose of which is to mitigate g force loading from aborts and from reentry from deep space. The Lockheed CEV was never intended for runway landings like the lifting bodies of earlier NASA program which used lifting bodies with an l/d of around 3.<br /><br />As for the X-38...<br /><br />"The X-38 design closely resembles the X-24A lifting body flown at Dryden from April 1969 to 1971. "<br /><br />http://www.nasa.gov/centers/dryden/news/FactSheets/FS-038-DFRC.html<br /><br />As has already been shown, the X-24a landed with regular landing gear. The only reason the X-38 uses a parafoil is because of it's mission as a Crew Rescue Vehicle. The X-38 was never intended for use as some sort of reusable vehicle which could benefit from conventional landing operations.<br /><br />By using a parafoil for landing the X-38 can land at many more places than a runway, so the parafoil improves the utility of the X-38 as an emergency rescue vehicle. Most of the development money and difficulty of the X-38 program was due to the very large parafoil chute designed for the vehicle.

 

[mrmorris]

<font color="yellow">"If the lifting body program was really just an "aeronautics" project maybe mrmorris can tell us about the mystery aircraft the lifting body program was designed to support? "</font><br /><br /><b>aeronautics</b><br /><br />n : the theory and practice of navigation through air or space [syn: astronautics]<br /><br />Pretty please at least create arguments for things that I actually say in my posts. I didn't say it was for an airplane, G&R, I said it was an excercise in aeronautics. You might have preferred that I call it astronautics -- except for the fact that the craft in question never made it into space <b>and</b> the only portion of flight where lifting body characteristics really make any difference is in air -- ergo aeronautics. Buy a dictionary. They were creating an airframe to see if it was possible to make an unpowered landing with a lifting body. The fact that they were able to get their test airplane to land does *not* mean that the principle is one that is feasible to carry forward into a spacecraft.<br /><br />Just to forestall your next post -- feasible is <b>not</b> a synonym for <b>possible</b>. Everything comes with a tradeoff -- it may well be possible that making a lifting-body reentry vehicle that does not require a parachute simply requires tradeoffs that are <b>worse</b> than having a parachute.

 

[mrmorris]

<font color="yellow">"Pretty thin and about what I expected."</font><br /><br />Pots and kettles there, G&R.<br /><br />Both the X-38 and the LockMart CEV were designed with parachutes for a reason. You might not <b>like</b> the reason... but it exists nonetheless. If a non-parachute assisted runway landing is so incredibly easy and has such great benefits... where are the LBRVs? If what I said was incorrect and a parachute-assisted landing is not a general rule -- then where are all the LBRV designs that don't use them? Trying to claim that the X-38 and LockMart CEV "don't count" is pretty lame.<br /><br />You've taken yourself way out on a limb by essentially arguing as if I had claimed that it was <b>impossible</b> for an LBRV to land without a parachute. When I pointed out that wasn't the case in my previous post, you had a chance to come back to the tree. Instead you're edging even further out and the branch is making some ominous cracking sounds. Either give evidence why parachute landings is not a general rule or learn to fly.

 

[cdr6]

Ok lets look at this from another angle... What are the requirements? If we were to look at a commericial vehicle intended for passemgers we need to find the break even point for number of pax to make operations a profitable. (Ouch! This is going to hurt...$$$ wise) <br /><br />The pax are going to be nonastronaut types so they want a shallow approach to landing, and airline like ammenities and ride... I think solid booster are a no-go for this kind of operation. <br /><br />So we are looking at something the about the size of the current shuttle-orbiter. (Smaller fuselage, bigger wings.) Crew and passengers not to exceed 30 folks. <br /><br />To an I.S.S. and back is just not going to pay the freight. So the space station is going to have to be a stop off, with the finial destination being either europe or the orient. <br /><br />Over all the craft might have a shuttle-X20 look to it, with the next generation becoming a blended wing body machine ala the SR 71.<br /><br />Pushing today's technology a little it might be do able. <br />