An orbital one-man version of SpaceShipOne?

[drwayne]

"130 km is good enough for a single orbit isn't it?"<br /><br />Depends on the overall thermal budget. It also might be a little stressing on the fuel budget as well.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[wvbraun]

I have fixed the link.

 

[scottb50]

Perhaps using the SS-1 concept as a second stage with a small third stage would allow pickup by a Tug based at a hotel, or other facility at a much higher orbit. I don't know about 81 miles though, I would think you would need enough margin to coordinate rendevous. <br /><br />Unless you get more than 300 miles or so the propellant for constant reboosts would be pretty expensive. <div class="Discussion_UserSignature"> </div>

 

[kmarinas86]

Maybe rutan is thinking about an aerodynamic space station.

 

[scottb50]

There is no reason for a Space station to be aerodynamic. Maybe your thinking of the Airship idea with longterm platforms at high altitudes. <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

What about this -- a space station at an orbit that is low enough to generally be considered 'short term' (although 130km is probably *still* too low), with an electrodynamic tether system used to provide a constant 'lift' to keep the orbit from decaying.<br /><br />It would have a couple of very useful advantages:<br /><br />- First (obviously) the lower the orbit, the cheaper it is to send people and supplies to it.<br />- Second -- because the orbit isn't stable without assistance -- the chances of the space station being hit by orbital debris would be reduced <b>significantly</b>. Nothing will stay there long without active assistance.<br />

 

[scottb50]

I would think to be a station the structure would have to be fairly large with a lot of interior space to be an effective hotel. I doubt much below 200 miles would be that stable either and like you say would need frequent re-boost or contant boosting to stay in orbit, just like ISS. Combined with the hazards at lower orbit from debris something like 400-500 miles would probably be much better.<br /><br />Trying to make a vehicle that takesoff with a decent payload, reaches those altitudes and then returns with a payload creates the same compromises the Shuttle has, it loses payload capabil.ity the higher it goes. Columbia was even too heavy to make it to the ISS. <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>Columbia was even too heavy to make it to the ISS.</i><p>No it was not. While it is true that <i>Columbia</i> was a few thousand pounds heavier than the other Orbiters, it wasn't so heavy as to make ISS missions impossible. NASA took the decision that since: (a) they didn't <b>need</b> four Orbiters to build the ISS; and (b) <i>Columbia</i> was heavier and therefore couldn't haul the really big components up to the ISS they would wouldn't install the external airlock so that they had the full length of the payload bay available for large objects (such as Chandra or the SpaceHab double research module).<p>During <i>Columbia</i>'s last ODMP they managed to remove enough excess weight that it became feasible to have her do crew-exchange and resupply missions. One of the mods they made was to install the harnesses and wiring for the ODS and external airlock. She was scheduled for at least two or three U/LF missions in the old assembly schedule.</p></p>

 

[scottb50]

Thanks, I do remember hearing they had lightened Columbia some and it could be used, but I thought originally it couldn't get that high at all because it was structurally too heavy by 2,000kg or so. I guess I missinterpreted the reason it was not originally assigned, though as you say it was limited more by the construction type cargos being flown, though the margin is still pretty close when you consider the overall weights involved. <br /><br />It does point out though how a little weight makes a big difference. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

I've know people who have been killed in airplane crashes and know something of how you feel. Stress can do bad things, I think that's a big part my health problems came to the forefront when they did. The airline I was flying for was about to be shut down, my wife has a very painful and dibilitating illness and we were losing our insurance, ect.<br /><br />It has always amazed me that just a little added weight can have such a large effect on a launch vehicle, we always laughed about the 160 pound average passenger and the rediculous bag weights we used on our weight and balances because though 10% sounds like a lot it really isn't that significant, in an airplane, 1 or 2% can make all the world of difference for a launch vehicle though.<br /><br />That's why I still think it is better to break it down into two different vehicles that can be most efficient in what they do. A launcher than can get to a minimal orbit and return as cheaply and safely as possible and a Space based Tug that never enters the atmosphere and continues the journey into different orbits. <br /><br /> <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"I doubt much below 200 miles would be that stable either and like you say would need frequent re-boost or contant boosting to stay in orbit, just like ISS. "</font><br /><br />drwayne's post early in this thread gave a link to orbital heights and lifetimes. Posting that data here (with mile conversion added):<br /><br />At 100km/62 miles your orbit lasts about an hour.<br />At 150km/93 miles your orbit lasts about a day.<br />At 200km/124 miles your orbit lasts about a week.<br />At 250km/155 miles your orbit lasts about a month.<br />At 300km/186 miles your orbit lasts about a quarter.<br />At 350km/217 miles your orbit lasts a bit under a year.<br />Anything above 1000 km/620 miles will stay up for 100+ years...<br /><br />Use of an electrodynamic tether (theoretically) would provide long-term propellantless orbital boost that should stabilize lower orbits.<br /><br /><br /><font color="yellow">"Combined with the hazards at lower orbit from debris something like 400-500 miles would probably be much better. "</font><br /><br />The ISS is at ~400 kilometers -- and as you say -- needs periodic reboosts, although I'd hesitate to call them 'frequent'. 400 miles = 643 kilometers -- over 50% higher than what the ISS is at. The shuttles couldn't get there with any significant payload -- it's certain that a private rocket won't be getting there anytime soon. Radiation hazards are also increased at that altitude.<br /><br />Also -- the hazards of orbital debris will be *smaller* at low (short-duration) orbits, as the debris themselves only stay in orbit a short time until they enter the atmosphere and burn up. This was one of the points of my post. Actually -- as I was going home yesterday, I thought of several more advantages to a low orbit for a 'space hotel'<br /><br />(A combined list)<br /><br />- The lower the orbit, the cheaper it is to send people and supplies to it. <br />- Because the orbit isn't stable without assistance -- the chances o

 

[halman]

Scottb50,<br /><br />What many people believed was the best kind of space transportation system back in the early days consisted of at least 3, or possibly 4 elements.<br /><br />1.) Flyback booster, which carried an orbiter vehicle to altitude for launch.<br /><br />2.) Orbiter vehicle, launched at aprox. 50,000 feet, capable of reaching 120 to 200 mile orbit.<br /><br />3.) Some visionaries believed that an Orbital Transfer Vehicle would be used to transfer passengers/payload from 120 mile orbit to orbit of space stations.<br /><br />4.) Space stations in 200 mile or higher orbits, where assembly of lunar shuttles, Mars transfer vehicles, etcetera would be done.<br /><br />Today, we are still looking at creating some kind of infrastructure such as this to make spaceflight affordable. The space shuttle was originally considered a test bed, to prove out winged re-entry.<br /><br />So much time has been lost that we are now facing building all of these elements again, only THIS time we need to do it all at once, so that an individual element does not become obsolete before the other elements are completed. If we had done things properly, there would have been space station components flying on shuttles by 1983. A second generation space shuttle would have replaced the originals long ago. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[scottb50]

Which is exactly what I have been advocating. A single Module design that can be used for all of the stages. Propellant tanks for a Launcher and Tug, elements for Stations and Vehicles and Lunar and Martian Habitats.<br /><br />Identical design, various sizes, materials and internal configurations depending on the use, and universally connectable to form any size configuration needed. Sort of the Lego approach. <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[spacester]

Nice reference table. Those are interesting thoughts on low orbit stations. Well I'm on a total math spree right now anyway . . . meanwhile . . .<br /><br />Here's some more Orbital Decay Calculations for reference. <br /><br />edit:<br />Looking at the example in the link and my spreadsheet, I'm seeing about 70 m/s deltaV needed every 46 days. Fudge those up a bit for a rough rule of thumb of 2 m/s per day. I could see an electrodynamic tether doing that, any experts on the subject?<br /> <div class="Discussion_UserSignature"> </div>

 

[mikejz]

The only problems that I could see are<br /><br />1. Electrical needs of such a teather...the weight of solar panels needed to power it in the end not be worth the advantages of the lower orbit.<br /><br />2. EVA safety issues...if a spacewalker while working on the station were seperated, the may only have a few hours to rescue him/her before they reenter.<br /><br />3. The View

 

[kmarinas86]

Why not have angled deflectors so that the particles bounce downwards while moving (or spinning) the space station upwards? If a (wingless) space station is more aerodynamic or if it has a shorter cross section... would it be able to stay up longer?

 

[radarredux]

> <i><font color="yellow">only THIS time we need to do it all at once, so that an individual element does not become obsolete before the other elements are completed.</font>/i><br /><br />I do find it sadly ironic how people used to lament that the early vision of the space shuttle was a shuttle to a location (e.g., a space station), and just as the location is completed the shuttles will be retired. And then America will have no way to get to the space station. And then soon after we have independent means to the space station again (via the CEV), we will abandon the space station.<br /><br />It is as if the entire manned space program from 1972-2015, 43 years of effort and money, is being deleted. ctrl-alt-delete. reboot.</i>

 

[bobvanx]

>would it be able to stay up longer?<br /><br />errm, no.<br /><br />Any last dregs of atmosphere are striking and slowing it down. Unless you add energy to a system that has losses, the losses will eventually overtake you.<br /><br />The cross section is a factor, but angles of deflection are not.