Reusable Non-Space Plane

[delta26]

It looks like this has been discussed before but I want to start off in a different direction.<br /><br />There seems to be a feeling that the capsule design of the Orion is a "step backward". Yet nobody seems to consider the Soyuz TMA a step backward, or the Shenzhou for that matter.<br /><br />The General consensus is that a reusable spacecraft will be the only way to make space flight economical, and that such a spacecraft must be of a winged or lifting body type design.<br /><br />What's wrong with a reusable capsule?.<br /><br />Obviously the ablative heatshield would need to be replaced every flight, but the cost of checking and refurbishing the rest of the vehicle couldn't be any more than turning around a Space Shuttle Orbiter.<br /><br />Now there's also the launch vehicle, It also doesn't need wings to be reuseable, the shuttle SRBs are essentially a reusable first stage, It's more difficult to make a reusable second stage.<br /><br /> The best solution I've seen for this is Kistler 's design. their crew capsule and second stage are one spacecraft. Now this poses design challeneges, but they can't be as great as those for a SSTO winged vehicle.<br /><br />In short, I think designs like those of Kistler and SpaceX(Falcon 5/9 supposedly fully reusable) should be given more credit. People seem to put launch vehicles and spacecraft in two categories: Those with wings that can be reused, and those that can't. The real solution may very well lie between those two.

 

[gunsandrockets]

There's reusability and then there's reusability.<br /><br />Take the Shuttle SRB for example, technically they are 'reusable' but even so they are so expensive to reuse there is no cost savings compared to a disposable system. Since the SRB is a solid engine it has to be broken down and rebuilt for every launch. The recovery parachutes undergo extensive inspection and repair after every use. All in all the Shuttle SRB are huge pain in the a**.<br /><br />As far as a system with some practical reusability, the t/Space design concept only reuses the very large launch aircraft and the manned capsule while it's two-stage rocket is disposable. The USAF so-called 'hybrid launch vehicle' is another practical idea which uses a winged flyback first stage and a disposable solid propellant second stage. An older idea was the Lockheed StarClipper 1-1/2 stage vehicle which was a reusable VTHL lifting body powered by three SSME and using a diposable drop-tank.<br /><br />There's many ways to get to greater reusability. Almost no-one proposes a SSTO HTHL 'spaceplane' as a practical solution to cheaper spaceflight. That sort of 'spaceplane' is usually a strawman position put forward to attack those who support alternatives to a non-reusable Apollo-type capsule system.<br /><br />

 

[holmec]

I don't see anything wrong with a reusable capsule, except the landing where in the past you couldn't steer the capsule as you came down with parachutes. But today we have dirigible paragliders so if one was to be installed on a capsule then the pilot could steer it to the appropiate landing site.<br /><br />Other than that I guess its the romanticism of a spaceplane. But capsules have been a proven way to transport asto and cosmo-nauts, although so far non reusable. <br /><br />Which in my mind begs the question what is the difference between a usable and unusable capusle? Does stress fracture appear on the sturcture of the non-reusable capule, or is it trashed with contact with the earth or what? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[scottb50]

One option could be dropping the heatshield after re-entry, it's expendable anyway, and using engines to land similar to the Delta Clipper design. Parachutes to keep the descent reasonable, engines to allow maneuvering and a controlled landing. Not that different than Soyus, other than it would be better to have some maneuverability rather than simple braking. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

Expanding on that the landing engines could be turbojets, not rockets. Attached to the underside of the capsule and swung out when the heatshield drops away, the capsule could land like a helicopter, or Harrier. <div class="Discussion_UserSignature"> </div>

 

[qso1]

delta26:<br />What's wrong with a reusable capsule?.<br /><br />Me:<br />Nothing. I think the CEV or whats now called Orion is designed with limited reusability. 10 flights IIRC. The capsule isn't the problem. Its the cost of the LV to get a capsule up each time. Starting with limited launch locations. KSC is the primary and only east coast site where large LVs are launched. A typical complex consists of usually two pads. LV production and two pads limits todays LV launch rate rather low which keeps costs relatively high because economies of scale are not realized, even with Delta rockets.<br /><br />Add to this the launch site, KSC which is limited to sparcely populated areas with huge ocean expanse in the direction of flight, both for range safety reasons and limiting the local human population to lower acoustical exposure.<br /><br />The reason a winged vehicle is seen to have an advantage is that if designed for economy from the start, launch location can be expanded. Especially for winged vehicles that can take off like an airplane. The problem with winged vehicles however is that nobody has been able to successfully build and operate one economically. They seem to still be beyond our technical ability and certainly beyond our ability to build relatively cheaply, that is like airplanes.<br /><br />Capsules and winged have advantages and disadvantages. We really havn't been able to fully explore any winged advantages in an operational way. For a program like VSE, winged vehicles are desirable but not absolutely necessary and going to a capsule design makes economic sense in an era where it appears human spaceflight will never enjoy the Apollo era budgets it once did.<br /><br />Private industry/enterprise may yet solve the winged problem and if so, VSE might be able to replace Orion with a winged vehicle if such a vehicle has definite advantages over launching/recovering capsules. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[willpittenger]

What does HTHL mean? I could not find it in Wikipedia. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[gunsandrockets]

"What does HTHL mean?"<br /><br />Horizontal Takeoff Horizontal Landing

 

[willpittenger]

I did propose one a while back, but assuming the time was 50-75 years into the future. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[barrykirk]

Welcome to the board delta26....<br /><br />The general consensus is NOT that a reusable vehicle must have wings.<br /><br />Also, there are several terms that I have used in the past to discuss these issues.<br /><br />Reusable - Which to me means, well, reusable. Like an airplane. Refuel it, give it an inspection and send it back on it's way.<br /><br />Refurbishable - Which would be like the shuttle SRB, whereby the cost of refurb approaches or can exceed the cost of a new item.<br /><br />Expendible - Self Descriptive.<br /><br />Partially Reusable - Which might be a good way to go. Make the expensive stuff reusable and the cheap stuff expendible.<br />

 

[holmec]

I say an outboard prop. just to provide some maneuverabiltiy.<br /><br />But turbojets for vertical landing requires a lot of fuel. That may not work. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[gunsandrockets]

"Not a good idea due to the high forward speed of the paraglider. The big paragliders can not be flared like a smaller paraglider."<br /><br />No reason a parasail couldn't be combined with soft-landing touch down rockets to kill the forward momentum of the parasail. No flaring neccessary.<br /><br />"Have you ever seen a video of the X-38 landing?"<br /><br />Are you saying the X-38 didn't work?

 

[spacester]

My understanding is that the X-38 program had the unfortunate distinction of determining the upper bounds on the mass of spacecraft that can be safely landed using paraglider technology. <br /><br />IOW going bigger was shown to be impractical.<br /><br />I hope to be wrong in this. <div class="Discussion_UserSignature"> </div>

 

[holmec]

>Not a good idea due to the high forward speed of the paraglider. The big paragliders can not be flared like a smaller paraglider. Have you ever seen a video of the X-38 landing?<<br /><br />Well, maybe a special design for a paraglider/parachute would be appropiate. Any way, you can slow a paraglider for landing, or just cut the cords. People in paragliders slow their, velocity for landing and end up taking one or two steps forward when its done right. <br /><br />Why would size of a paraglider hinder its flarability? If its controlled by electic motors, there shouldn't be a problem. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[vulture2]

>>Have you ever seen a video of the X-38 landing?< <br /><br />In the one X-38 drop test that was done the parasail failed to deploy properly because of a mechanical problem. The program was then cancelled befor fixing it. Large parasails can be flared.<br /><br />The Russians have dropped large military tanks by parachute, with a terminal rocket decellerator like the Soyuz has. The US DOD has a development project for a 15 ton capacity parasail. There is also a sytem that uses a small parasail drouge to guide the payload down to a low altitude, then when directly over the landing zone at low altitude a large round chute is delployed.<br /><br />However the CEV will use the simplest solution - round chutes and a large landing area.

 

[scipt]

I thought that the Russian Kliper design atop the Soyuz, Ariane or the new Russian launchers looked great. I hope that Energia still pursue this option (despite cancellation of Rosviacosmos funding). There is a good chance they will IMO. I'd like to see the newly rich Russia and EU co-operate more in space. We got shafted by the US over the ISS so i think next time ESA would be sensible to go with Russia or China. <br /><br />My feeling is that in reality the US prefers to do space on it's own. No harsh feelings, i just sense that. <div class="Discussion_UserSignature"> </div>

 

[holmec]

>Those are small paragliders, large ones required to land a large capsule is a very different story. Believe me I know how small apargliders and parachutes land I have been flying them and jumping with them for 45 years. Well the first 20 of those years was with round parachutes.... find a video of the X-38 to see how well a paraglider can be landed....not very well. Plus you need skids.<br /><<br /><br />Ok, ok. What about using round chutes and modified to provide some directional control while the capsule is coming down? Would that be in the realm of possibility? I would think it would be. Because even with round chutes if you pull on one side othe the ropes you change direction. Maybe your right and a paraglider is not the answer. Maybe a new kind of chute will provide directional control.<br /><br />I just think its kinda risky just letting the wind decide where your landing. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[mrmorris]

<font color="yellow">"I just think its kinda risky just letting the wind decide where your landing. "</font><br /><br />Let's look at what kind of wind-based displacement we're looking at:<br /><br />For Apollo 17, main chute deployment occured at 10,000 feet and the terminal velocity was 30 ft/sec. This means that there was ~330 seconds (.09 hours) from main chute deplyment to splashdown<br /><br />If we assume a 30 mph wind (near gale force) at the time of landing, the <b>maximum</b> displacement due to wind would be 2.7 miles (30 * .09). 10 MPH winds and a maximum displacement of .9 miles are more likely. Beyond that -- even hanging from the parachutes, the capsule is not going to move at exactly the speed of the wind so <b>actual</b> displacement would be considerably less than the maximum. Overall, the 'steering' from a parachute is probably going to buy less than a mile. This isn't worth the added complexity and risk of complicating the parachutes.

 

[webtaz99]

How dare you bring <font color="yellow">math</font>into an engineering discussion?! <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> </div>