Community > Forum > Technology & Science > Combining?

Combining?

Posted by: Ekkehard Augustin - Wed Mar 16, 2005 3:57 pm
Post new topic Reply to topic
 [ 7 posts ] 
Combining? 
Author Message
Moderator
Moderator
avatar
Joined: Thu Jun 03, 2004 11:23 am
Posts: 3745
Location: Hamburg, Germany
Post Combining?   Posted on: Wed Mar 16, 2005 3:57 pm
There are two threads in the ASP section that are discussing air launch for orbit a little bit - "Possible Craft" and "An-225 as white knight?". In the last one I proposed to look for different versions of combinations of air launch with ground launch.

Rutan is preferring air launch because of safety but those who favour ground launch - vertical - have their good reasons too.

Now there are two things that might provide ways to combine air launch with ground launch:

1. It is possible to fuel one airplane by another - the technology is used by the air force and they are experienced in that.

2. t/Space has worked out a concept to launch the manned vehicle first and then to do an air launch of tanker vehicles to fuel the manned vehicle.

If I understood right the Delta 4 Heavy is able to reduce thrust and then to increase it again - this is a third point that might enable combinations of ground launch to air launch.

Using all this I could imagine in theory that a manned vehicle is launched by air launch and has suborbital velocity then - this is done for safety of the passengers and the environment. From another place not too far away an unmanned vehicle is launched by ground launch after the air launch of the manned vehicle is done. The unmanned vehicle is capable of carrying the manned vehicle to orbit - and it can modify the thrsut of its engine.

Now the unmanned vehicle goes up quickly by high thrust to get close to the manned vehicle and reduces thrust and speed when the distance to that vehicle is sufficiently close. Then it uses an improved and modified version of the technique a tanker airplane is using to connect to another airplane - it uses it to dock to the manned vehicle and then the distance between both vehicles will be reduced quickly until the manned vehicle is completely tied to the manned vehicle.

Then the unmanned vehicle increases thrust and velocity up to those required to achieve the orbit. The angle of ascent will be adjusted to the requirements too.

Another idea could be to launch the unmanned vehicle from a DSS - if a DSS with such a capability already would be provided by JP Aerospace. May be that this would be easier because the unmanned vehicle wouldn't need to slow down perhaps - it wouldn't have to follow the manned vehicle. Instead of that the two launches could be timed so that the manned vehicle meets the unmanned vehicle during that phase of launch the two velocities are equal or sufficiently similar in. But in this case the unammned vehicle wouldn't have a ground launch but a vertical launch only.

In both cases it may be possible to undock the manned vehicle in case of danger.

I have been looking it under the aspect of infrastructure and infrastructural process mainly which is an user-aspect or a commercial aspect mainly.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Sat May 22, 2004 8:59 am
Posts: 578
Location: Zurich
Post    Posted on: Wed Mar 16, 2005 4:27 pm
Completely insane. As someone so unbelievably glued to the "air-launch to orbit" concept you've dreamed up a series increasingly improbable scenarios to say it can be done. This last exceeds even the wildest dreams of vapor-ware nuts.

DKH

_________________
Per aspera ad astra


Back to top
Profile
Moderator
Moderator
avatar
Joined: Thu Jun 03, 2004 11:23 am
Posts: 3745
Location: Hamburg, Germany
Post    Posted on: Wed Mar 16, 2005 5:03 pm
It wasn't a dream - I simply theorized about a way to combine air launch with ground launch or vertical launch. There are other ways to combine them I suppose. It's just a raw concept under the economical aspect of organization and/or coordination - something like that what's called allocation in Economics.

Given the current technologies and their current state of the art it may and will be unsane - but this can be taken a s a reason to change that state of the art and that technologies to remove the unsanity from such ideas, to increase the safety etc.

It would be a large challenge if not a huge one but it might be possible to succeed.

The question simply is what has to be improved to increase the safety of it, what technical numbers have to be achieved compared to the current technical numbers. Try to make all equipment and engines more precise again and again until you don't achieve something anymore (for example) - try to achieve the farthest you can achieve and when you don't achieve progress anymore compare it to what is thought to be required then. If the requirements are met at least than the idea is realistic - if the requirements are not met then it's unrealistic.

Improvement, improvement, improvement - development, development, development. With a long breath. Very lot of unmanned rendezvous tests beginning at small scale. Try what you can achieve - and don't decide against it before you miss further progress.

What has to be done? What has to be improved? Radio? Capability to adjust velocities to each other? Precisety of velocity adjustment? Capability of direction adjustment or its exactness? Docking technology? Handling share winds and other sudden winds? Capability to regulate thrust and velocity? ... I would like to see such improvements or developments to be done... Some of them will be required to dock to Nautilus too and they will be required to dock to JP Aerospace's DSS too - so it will be of use nearly all the way.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Back to top
Profile
Moon Mission Member
Moon Mission Member
avatar
Joined: Tue Feb 10, 2004 2:56 am
Posts: 1104
Location: Georgia Tech, Atlanta, GA
Post    Posted on: Wed Mar 16, 2005 9:00 pm
Absolutely stupid. Flying two vehicles in formation at a hundred miles an hour takes years of careful training and practice just to be able to reduce the risk of shredding your buddy's wing down to somewhere below certain.

Docking two vehicles at the peak of a parabolic trajectory is so difficult as to be practically impossible. Not to mention the fact that fuel lines, electronics, and life support would all have to be somehow hooked up between the manned vehicle and the unmanned booster stage in the split second it takes to dock.

In-flight refueling is a very precisely planned and extremely dangerous operation. The USAF, USN, and USMC have worked for many years to minimize the risk to the flight crews. Even so, accidents still happen on a fairly regular basis. Actually mating two vehicles -- a process with a tolerance of an inch or so -- in flight, at high altitude, with practically no control over either vehicle and an operational window of under a minute, is absolutely insane.

It is not physically possible to make this in any way, shape, or form, a safe procedure. Go ahead, ask somebody from JPL. They'll be happy to tell you the same thing.

I really hate to be mean, but I think I might have to be in this case: Economics does not apply to engineering. The most economical ideas usually don't work, because of the interference of a small detail called the Laws of Physics. In order to be a reasonably non-dangerous engineer, you have to know physics intuitively, and be able to sniff out the few Bad Ideas that are buried within a lot of Okay Ideas. Then, and only then, can you start to come up with Good Ideas.

You have the capacity to come up with a few Good Ideas of your own -- but first you must understand the physics of the situation entirely, and be able to find holes in your own logic. You don't yet have the ability to take a step back from your own arguments and examine them rationally and detachedly.

_________________
American Institute of Aeronautics and Astronautics
Daniel Guggenheim School of Aerospace Engineering

In Memoriam...
Apollo I - Soyuz I - Soyuz XI - STS-51L - STS-107


Back to top
Profile
Moderator
Moderator
avatar
Joined: Thu Jun 03, 2004 11:23 am
Posts: 3745
Location: Hamburg, Germany
Post    Posted on: Thu Mar 17, 2005 7:33 am
Sorry - I wasn't applying Economics to engineering. That's a misunderstanding I want to clarify:

If an economist is considering a purpose he asks what would be required to achieve that purpose. When he has got some answers to that question the he asks if these requirements can be met and which ways. Then he looks to that ways and chooses one (at least) - if there no ways that moment then he puts aside the question.

The question for the requirements and for to meet them is called allocation which is subject to a special theory of substantial meaning. The ways to meet the requirements are methods and technologies.

I simply described one version of allocation - and you provided objective and good answers describing another layer of requirements or a much more detailed allocation:

1. careful training
2. practice
3. hooking up fuel lines, electronics, life support
4. very precisely planning
5. much work to minimize risks

That it has been done in the case of in-flight fuelling by USAF, USN and USMC means that it can be achieved in the case of airplanes.

I may have a language problem currently - so I want to clarify another thing too: In my image the unmanned vehicle is an external booster only - I don't have in mind to integrate the two vehilce fully or to fuel the manned vehicle by the unmanned vehicle. Perhaps I caused misunderstandings by using the term "to dock" - I don't imagine to move fuel from one vehicle to the other or life support ressources from one vehicle to the other. I only imagine the unmanned vehicle to carefully catch the manned vehicle and carrying it to the orbit.

That I said to clarify only - I am not arguing currently. And I don't have in mind concrete vehicles or a future reality but abstract thoughts only - for this reason these thoughts are not under something like psychologic influence as would be the case if I would be sitting in an airplane that's going to be inflight-refueled - but I suppose I wouldn't be anxious in this case.

Good post, spacecowboy - objective, informative and indicating where I have to explain my look upon it.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Back to top
Profile
Moon Mission Member
Moon Mission Member
avatar
Joined: Tue Feb 10, 2004 2:56 am
Posts: 1104
Location: Georgia Tech, Atlanta, GA
Post    Posted on: Thu Mar 17, 2005 12:58 pm
Okay, that works just a tiny bit better -- I can kinda see a big rocket booster with a device that's some kind of cross between a bear trap and a butterfly net on top....

The big problem with that is that the docking mechanism (whatever it is) has to be on the nose of the booster. On the manned vehicle, the docking mechanism is on the tail, and can be faired into the fuselage to minimize drag (although it will still be significant). However, on the booster, the docking mechanism has to be on top, thus causing an insane amount of drag -- and wasting more fuel than I care to think about.

Also, the docking mechanism has to work perfectly, every time, and have absolutely no structural flaws in the action, otherwise the two vehicles rip apart when the booster fires.

It's still not a safe or practical idea. You're trying to do something with two machines what can be done with one -- it's far too overcomplicated, and there's too many places where it could break down.

_________________
American Institute of Aeronautics and Astronautics
Daniel Guggenheim School of Aerospace Engineering

In Memoriam...
Apollo I - Soyuz I - Soyuz XI - STS-51L - STS-107


Back to top
Profile
Moderator
Moderator
avatar
Joined: Thu Jun 03, 2004 11:23 am
Posts: 3745
Location: Hamburg, Germany
Post    Posted on: Thu Mar 17, 2005 2:42 pm
It could be done by one - but there are two groups at least: those preferring air launch (Rutan etc.) and those preferring gound launch or vertical launch. Both have arguments on their side.

And you are right - there are many problems to be resolved. But Rutan has arguments to say that about ground launch or vertical launch too whre as the opposite group has arguments to say it about air launch. This means three different allocation processes at least - the two already going on and the third under theoretical consideration here.

It's academic up to now - and may serve as catalysator perhaps. It can be a new point from which to look at the existing concepts too.

I would like the thread to go on.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)


Back to top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 
 

Who is online 

Users browsing this forum: No registered users and 16 guests


© 2014 The International Space Fellowship, developed by Gabitasoft Interactive. All Rights Reserved.  Privacy Policy | Terms of Use