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

[ldyaidan]

Good points there. Most average folks are either not going to be able to withstand the heavy G from lift off, due to health issues, or just simple discomfort. In order to allow the masses to get into space we will have to find something other than a rocket booster to launch. <br /><br />Just my 2 cents<br /><br />Rae

 

[vt_hokie]

The shuttle crews never experience more than 3 g during launch, right? That doesn't seem too excessive...probably on par with some amusement park rides!

 

[lunatio_gordin]

yeah. I think some rides get up to 4 or 5 Gs, actually ( i used to watch the travel channel all the time) <img src="/images/icons/tongue.gif" />

 

[mrmorris]

<font color="yellow">"Both the X-38 and the LockMart CEV were designed with parachutes for a reason. "</font><br /><br />*SMACK* (slaps self on forehead)<br /><br />G&R: <br /><br />I'm too US-centric. Forgot to add the <b>other</b> modern lifting-body spacecraft, Kliper. Of course I'm sure there's some reason you'll disqualify it from the list of LBRVs that use a parachute to land. I'm curious though -- why would it be eliminated?

 

[lunatio_gordin]

or one of my favorites, the kosmolyet.

 

[henryhallam]

<font color="yellow"><br />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.<br /></font><br /><br />Just a quick note for clarification - from what I have read in my PPL textbooks, adding weight without changing the airframe <i>doesn't</i> make the descent steeper. The angle of descent remains the same. What increases is the <i>rate</i> of descent. Of course this still translates as a more difficult landing.

 

[frodo1008]

I hate to rain on your parade here, but there is a BIG difference between amuzement park ride and the shuttle. Amuzement park rides give you the same g loads, however for every second of an amuzement park ride, the shuttle gives you a MINUTE of the same g load! Say, some 6 seconds (if that) at 3g in an amuzement park ride. and some 6 minutes of 3g in the shuttle, to most ordinary people, a VERY big difference!!

 

[henryhallam]

It doesn't really matter how light your spacecraft is, there isn't a way to keep it up in the very high atmosphere long enough to get rid of all the kinetic energy. You can start by lowering your orbit so it just skims the very high atmosphere but at some critical point it will slow down too much, and the next pass goes deeper, slowing more etc. in a runaway descent. The more lift your spacecraft has, the longer you can delay this but a glider must go down as well as forwards! So you still reach a critical point.<br /><br />w.r.t. SS1, it's worth remembering that the kinetic energy which must be dissipated scales as the square of velocity so although a spacecraft returning from orbit may only be travelling less than six times as fast as SS1, it has ~35 times the kinetic energy, which must be dissipated in a few minutes, no matter what shape it is.

 

[nacnud]

Yeah that would be too tame for the average fair ground goer, the gravitron gets up to 4g for 80 seconds or so. Three g for 360 seconds should be fine for a fit adult.

 

[henryhallam]

You can lose a bit more kinetic energy but you cannot glide forever. Each pass you make slows you down and causes you to dip further into the atmosphere, causing more heating and more slowing on the next pass etc. I understand the idea of trying to trade airspeed for altitude but I don't think it will work at such high velocities in an unstable situation.

 

[lunatio_gordin]

They do that. It's called retrorockets. I don't think they've been used for real on anything, but i'm not sure. I know the shuttle doesn't have them <img src="/images/icons/tongue.gif" />

 

[halman]

knowledge_is_power,<br /><br />There is a huge difference between flying an aircraft to the edge of space and atmospheric entry from space. About 5 miles per second, more or less. A spacecraft entering the atmosphere will not be gliding, no matter what its shape, it will be a ballistic object that can only be controlled by firing thrusters. As the velocity diminishes, a lifting body begins a glide path descent which is much slower than a ballistic object. When the velocity is down to several hundred miles per hour, a winged vehicle will have a slower rate of descent than a pure lifting body or a ballistic object suspended from parachutes. It will also have attitude control from the aerodynamic surfaces that can have their angle of attack changed, such as elevons and rudder.<br /><br />A great deal of the energy that you see being spent during launch has to be discarded some how during re-entry. The tiles on the shuttle absorb heat at a rapid rate, but radiate it off very slowly. This allows the shuttle to withstand the plasma-like temperatures during the first part of re-entry, which is dissipated from a ballistic object through ablation of a heat sheild. The chunks of superheated material which seperate from the heat sheild are carrying away energy, so that it will not be absorbed by the object.<br /><br />Using rocket power to descend all the way from orbital velocity means carrying rockets into space that are nearly as large as the ones that got you there. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[halman]

Syndroma,<br /><br />The vehicle that I have described uses a magnetic catapult built into a launching rail which supports the combined weight of the two vehicles. The carrier wing would land on conventional landing gear after seperating from the orbiter, and having burned most of its fuel.<br /><br />Using a catapult allows ground power systems to impart energy to the stack, decreasing the time to reach lift off speed, and reducing the amount of fuel the carrier wing must hold. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[halman]

gunsandrockets,<br /><br />Not being familiar with t/Space or its concepts for launch vehicles, I can only say that the design I have described allows very high flight rates, (as long as there is a large enough pool of orbiters,) and very narrow performance criteria. The system should be built to get mass to orbit on a frequent, regular basis. That is all. Operational versatility, such as landing at different airports, or supporting extended orbital stays, increase complexity and diminish efficiency. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[john_316]

i dont know about all of you as i have read alot of your posts but i don't see space planes like the NSAP X-30 until around 2040 onwards if we go into scramjet technology.<br /><br />maybe its a guess too...<br /><br />

 

[mrmorris]

<font color="yellow">"...from what I have read in my PPL textbooks, adding weight without changing the airframe doesn't make the descent steeper. The angle of descent remains the same. What increases is the rate of descent."</font><br /><br />Just a quick note for clarification -- that only applies if you're ignoring relative velocities of the lighter vs. the heavier craft. If you increase the rate of descent, but *don't* increase your forward velocity, then the angle of descent increases.<br /><br />You can state that the <b>desired</b> angle of descent is be the same, but to maintain a given angle in a heavier craft with no more wing surface, you have to be travelling at a higher forward velocity. This is one of the problems with landing LBRVs without a parachute... the speed required for a runway touchdown would otherwise be dangerously high. <br /><br />The parasail on the X-38 was there to add additional lift, which allowed for a lower forward velocity without having an unnacceptable drop rate. This allowed for a speed low enough for a safe runway (horizontal, anyway) landing. The problem with using parasails is that they are larger, heavier, and have a more complicated deployment than a parachute of the same lift capacity.

 

[frodo1008]

I have no doubt that you are correct in that space planes of the single stage to orbit variety are indeed decades away (unless some real break through is made in the hypersonic flight region).<br /><br />Also, it sounds like the immediate shuttle replacement is going to be some kind of capsule design. This is what NASA is quite probably going to use until pure private interests comes up with something else. It is NASA that has trained astronauts who have a far higher tolerance for discomfort that the ordinary person does. Mind you, not just the ordinary person, but at least in the beginning of the space tourism industry, the RICH ordinary person. And these are people who are generally used to at least comfort, if not genuine luxury!<br />This should satisfy those who think more highly of capsule designs.<br /><br />In the meantime it is now rather obvious (also see my earlier post) that the pure private interests are going to want to go with some kind of space plane. The people who not only won the x-prize, but appear to be well along on the route to actually coming up with a viable system for taking paying passengers into sub orbital space are Burt Rutan and his people. The method that they are obviously going to use is a two stage to sub orbit horizontal take off and landing space plane. Burt Rutan is going to build a larger version of spaceplaneone (I guess it would then be spaceplanetwo) and a larger version of the White Knight to carry it up to launch altitude. I think the capacity put forth is for six passengers and a pilot, which will indeed result in a larger combined craft. However, the increase will only be incremental, and not radical. And this incremental approach will be the name of the game for the private space tourism game from now on. As Rutan himself has already stated reliability and safety will BE number one, even placing being inexpensive in a secondary place. In this he is dead on! <br /><br />I would expect that like the aircraft industr

 

[gunsandrockets]

"Not being familiar with t/Space or its concepts for launch vehicles,..."<br /><br />See this thread for all kinds of cool details, discussion and images...<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=missions&Number=222554&page=&view=&sb=&o=<br /><br />Briefly, the t/Space manned orbital flight concept is an airlaunched liquid fuelled multistage rocket with a reusable manned space capsule. The rocket is carried up and then dropped at 25,000 feet by a large jet aircraft (the VLA for Very Large Aircraft). The rocket has two stages which burn LOX and Propane. The 6 man capsule has a rear facing docking interface and hatch. The capsule reenters the atmosphere nose first using active transpiration cooling as it's primary thermal protection system and recovers Apollo style by descending with parachutes and landing in the ocean.

 

[vt_hokie]

I notice that Lockheed Martin has removed its CEV page from its web site. I wonder if that means anything...

 

[gunsandrockets]

"I notice that Lockheed Martin has removed its CEV page from its web site. I wonder if that means anything... "<br /><br />Do you mean this page?...<br /><br />http://www.lockheedmartin.com/wms/findPage.do?dsp=fec&ci=16745&rsbci=16745&fti=0&ti=0&sc=400

 

[frodo1008]

What being discussed by the t-space sites is not a vehicle for private sub orbital flight, like the one that took the x-prize. This is indeed a very revolutionary vehicle concept for a full orbital vehicle for NASA. I don't know if this will be the shuttle follow-on itself, but it would certainly be the least expensive (once such big ticket items such as the very large aircraft are paid for, and they may even be thinking of modifying some existing aircraft) basic method of getting human beings into space at this time.<br /><br />It is no wonder that NASA seems a bit disorientated in coming down to what is exactly going to replace the shuttle.<br /><br /> Besides this excellent project and possibility, there is the possible use of the SRB. I wonder how much one of those alone costs per flight? This would be in combination with a capsule design similer to the t-space concept. <br /><br />Then there is the EELV option. What many on these boards don't seem to realize is that the EELV was not a NASA project at all. It was an Air Force project to bring down the high cost of launching a pound of material into LEO. It was to use reasonable technology (nothing purely for the sake of being radical in of itself) to push existing technology as far toward lower costs than it could be reasonably expected to be. With a reasonable launch rate (always a factor in launch costs, more launches = less cost per launch) I think it would be possible to get either the Delta IV Heavy or the Atlas V Heavy down to $1,000 per pound from today's $10,000 per pound to LEO. Another advantage for this system is the ability to add common booster cores to build launch vehicles with greater and greater payload weight, without truly radical re design of the system.<br /><br />So NASA has at least three, and possibly even more launch rockets and systems, even possibly being able to use multiple launchers with the same capsule vehicle, carrying astronauts. Decisions, decisions... <br />

 

[vt_hokie]

"Do you mean this page?..."<br /><br />Yes, that's the one! Thanks!

 

[hawkeye4640]

Do you think that when Orville and Wilbur made their plane they intended passengers to lay on their stomach when the plane was flying?? Certainly NOT people do not want to travel like that. The capsule was the first way, but RARELY is the first way the best way. You can always improve.<br /><br />If space travel will ever advance to some form of practicality, people need to travel in comfort. and landing in the water/ground through capsule is certainly not for the average/normal human. I certainly woudln't want to go through that.

 

[paleo]

A big issue in the future will be the environmental impact of many designs. A couple years later and the Concorde would not have flown. It's going to be tough sell to allow atmospheric pollution for the amusement of a few. I'm going to 'guess' that the environmental assessment of any future space planes, etc. will be as big a variable as whether or not they are technologically sound.

 

[vt_hokie]

Well, model rocket enthusiasts currently use ammonium perchlorate most of the time, right? That's probably worse than the hybrids that "Virgin Galactic" will be using, from an environmental standpoint.