Community > Forum > Perception, Barriers & Regulation of Privatized Space Travel > 2 cents

2 cents

Posted by: n54 - Tue May 18, 2004 10:47 pm
Post new topic Reply to topic
 [ 21 posts ] 
2 cents 
Author Message
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post 2 cents   Posted on: Tue May 18, 2004 10:47 pm
most markets don't exist before they are created (most "goods" didn't have much to do with any real day-to-day necessity before they got established)

- most people would like to experience space
so we get the ansari x-prize and "millionaires in space" for starters, it's a beginning. over time as initial investments starts to get covered the market will be broadened to include more people and prices will drop

ok now we have a suborbital market

- many people would pay a lot for cutting travel-time significantly on long trips like london-singapore, sydney-new york, tokyo-frankfurt etc.
seems to me not many modifications would be needed to make a ss1-type craft perform well as an intercontinental-through-suborbital service (travelling in the opposite direction of the earths rotation would probably be faster "both ways"). have some "refueling"/ground support and white knight plane's located at major airports throughout the world to launch the ssh1 after the passenger arrival/departure is taken care of and one might not even need that many ss1's to pass along

ok now we have a larger suborbital market and the tourism part needs to have a new "edge" as a lot of people are experiencing near-space and small periods of zero-g

- many people would love to experience true prolonged zero-g
the step from intercontinental-through-suborbital to orbital should be a minor one with a design similar to ss1 i.e. the combination of a lift-off stage (white knight) which fits into existing infrastructure and a blast-off stage (ss1 or payloads).

in the beginning this would surely just be something like 1 trip around the earth but from there on it's hard to see how it could stop (or even slow down)

i think there are several rich people out there realizing the enormous profit that can be had from something like this. i also think the scaled composites team are aware of this since they call what they're doing the "Tier One program"


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 Re: 2 cents   Posted on: Wed May 19, 2004 11:30 pm
n54 wrote:
<snip>


Might I note that although their plans might have changed, I seem to remember Scaled mentioning that the White Knight/SSO combination was not intended for any purposes other than feasability research; they don't seem to plan on putting it into business.

But otherwise, you're basically right.

_________________
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
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post Re: 2 cents   Posted on: Thu May 20, 2004 1:20 am
true, i don't think they've restated that part on business, nor that they will

i might be a bit overoptimistic but maybe what they'll do after they have:
1. gotten the x-prize if noone beats them to it, or gone suborbital and
2. completed their longer research on actual running costs (the reason for their one year of flights after going suborbital)
is to either start the faa approval process for airliner-like operation (so that they can build and sell the crafts to any budding spaceline company) and/or start to build a wk2/ss2 based on any profit-maximizing size they've discovered from their operational costs baseline

i'm guessing that they would do both as already having an faa certified space-liner, although small, if based on the same technology should make the certification process for the larger sibling go much smoother. i might be completely wrong but i'm thinking that the faa will feel the technology is more mature by doing it this way.

i also think think they could "cook" a new version pretty quickly as it's all composite materials

ok... so my dreams of a wk2/ss2 might be a bit over the top lol but at least i can't spot any reason for doing the year of "financial preparation" unless they want to get (a lot of) facts perfectly straight and documented for faa and future space-liner customers - that part seems rock solid (i hope :mrgreen:). it will of course also make perfect sense if one expects competition in the market and i think some of the other contestants (and others) will see to that :D


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 Re: 2 cents   Posted on: Fri May 21, 2004 11:57 am
n54 wrote:
<snip>


Not only can you expect a short development-to-production lag, but you can expect the design phase to be over with really quickly. The SS2 will likely be not just designed in CFD (computational fluid dynamics) programs, but actually optimized in them, similar to the Boeing 7E7 Dreamliner-Class. It's pretty impressive that computer technology has advanced enough to take most of the guesswork out of engineering.

Now here's my two cents' worth: I think we're going to see the SS2-equivalent carrying six or more passengers (maybe even twelve) for increased efficiency. I also think that although the White Knight/SSO combination is a pair of beautiful machines, I do not believe that it is any more than a novelty. Companies such as Canadian Arrow, StarChaser, and Armadillo (Go Widget!) will economically outrun Scaled Composites due to the inherently simpler nature of their launch vehicles and refit/launch operations

_________________
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
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post Re: 2 cents   Posted on: Fri May 21, 2004 2:13 pm
spacecowboy wrote:
...due to the inherently simpler nature of their launch vehicles and refit/launch operations

i'm not too sure about this part as i feel it's hard to compare the differences but my view is that ss1 can (or will be easily changed to) basically just fill the oxidizer tank and swap CTN's "battery style", and these are small compared to the rockets and fuel tanks of the other contestants. i'm thinking for business operations, not necessarily the ansari x-prize attempt itself.

it's hard to judge but i'm basing this view on the following: http://www.scaled.com/projects/tierone/New_Index/data_sheets/html/ox_tank.htm

armadillo might be simpler to refuel but i'm not convinced that the launch vehicle itself is simple (the opposite imo)

i think starchaser/canadian arrow will use a bit of time on transporting their stages back from their parachute landing spots and whether or not they drop in water or onto land it looks like a more extensive launch cycle

i guess it boils down to scaled having 1 rocket engine and 1 fuel tank to check/refuel/refurbish while all the others have more, and that scaled has no time spent on stage retrieval (armadillo is planning for this as well)

i might be completely wrong and would like to hear [see] your detailed opinion


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Mon Oct 06, 2003 9:22 pm
Posts: 844
Location: New York, NY
Post    Posted on: Fri May 21, 2004 10:12 pm
i agree, after armadillo, scaled should have the fastest turnaround time once their vehicle is fully tested. with some modifications they may even be able to get it down to close to armadillo, but due to the nature and precision of their design (not that scaled doesn't have the precision part), they ought to be able to refuel and fly their vehicle in under the time it takes to do so for a commercial airliner. that might not be the safest procedure, but it certainly would work, and would be pretty awesome if they make another vehicle designed for moving payloads.

_________________
Cornell 2010- Applied and Engineering Physics

Software Developer

Also, check out my fractals


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 Re: 2 cents   Posted on: Sat May 22, 2004 4:33 pm
n54 wrote:
<snip>


The biggest reason I don't "like" Scaled's design as much as Armadillo's is that SS relies on another airplane to take it to launch altitude. It has to rely on another vehicle; thus, the size of the launch vehicle is limited by the carrying capacity of the carrying vehicle. This makes for extreme inefficiency when you're dealing with a launch vehicle too much bigger than SSO.

In their document Flight Mechanics of Manned Sub-Orbital Reusable Launch Vehicles with Reccomendations for launch and Recovery (AIAA 2003-0909), Drs. Marti and Nesrin Sarigul-Klijn of UC Davis mention the "Captive on bottom" carry approach:
Drs. Sarigul-Klijn wrote:
Disadvantages include limits to RLV size due to under the carrier aircraft clearance limitations...
("Flight Mechanics...", Page 9)

A short list of other problems:
•Although most vertical-launch rockets can use gravity-assist-feed propellant tanks (meaning that the fuel pump is smaller and lighter because the acceleration is working with it), horizontal-launch and captive-carry vehicles cannot. These vehicles must rely on bigger and bulkier fuel pumps which weigh more and require more electrical power, which in turn requires more fuel.
•Due to the necessary pitch-up of the RLV (since it is launched horizontally), the vehicle must be designed to take not only the axial acceleration forces, but also twisting forces along the normal direction. This means that the RLV must not only be designed for strength but also for stiffness, thus increasing the weight.

In another paper, A Study of Air Launch Methods for RLVs (AIAA 2001-4619), Drs. Sarigul-Klijn explain that air launching does not always reduce the delta V required for the RLV:
Drs. Sarigul-Klijn wrote:
Surprisingly, a typical straight and level subsonic horizontal air launch such as used by the X-15 research rocketplane does not result in any significant changes in the delta V requirement as compared to a baseline vertical surface launch. Horizontal launched vehicles like the X-15 must accelerate to a higher airspeed after being dropped so that their wings can produce enough lift in order to conduct an aerodynamic pull-up maneuver. Typically a descent of 4,000 to 7,000 feet occurs until sufficient airspeed is obtained. The pull-up maneuver is limited to 2 to 3 G's due to airframe and wing structural limits and takes about 1 minute to reach a climb-out angle of 45 to 80 degrees nose-up. During the one-minute pull-up maneuver, aerodynamic pressure increases, and the launch vehicle is subjected to both high sideways bending moments as well as high aerodynamic pressure. For example, the Orbital Science's air launched Pegasus XL experiences over 1250 pounds per square foot (psf) aerodynamic pressure, twice the Space Shuttles, even though it is launched at 38,000 ft.
("Study...", Page 3)

On the other hand, a vertically-launched rocket does not experience these problems:
Drs. Sarigul-Klijn wrote:
A vertical takeoff rocket can easily carry the necessary propellant mass fraction required to reach 100km (328,000 ft). Vertical takeoff vehicles also have significant margin that allow them to use relatively low technology pressure fed rocket motors. Vertical takeoff rockets are basically pressurized balloons under an axial compression load and are subject to very little bending and no twisting moments during takeoff. Unlike horizontal takeoff vehicles, precise longitudinal control of center of gravity is not required which eliminates the need for multiple bulkheads inside their fuel and oxidizer tanks and eliminates the need to intertank propellant transfer pumps. … Vertical takeoff has been picked by every space transportation study during the past 20 years as the preferred takeoff method for an earth to orbit RLV. These studies include the European Space Agency's (ESA) Future European Space Transportation Investigations Program (FESTIP), Russian's Oryol program, Japan's HOPE, and the United States' Access to Space Studies, Space Transportation Architecture Studies, and most currently the US Space Launch Initiative (SLI).
("Flight Mechanics...", Pages 5 & 6)

Thus we see that although Scaled Composites with their White Knight and SpaceShipOne has the lead in the Ansari X Prize competition, companies using designs similar to Armadillo Aerospace's Black Armadillo, and eventually single-piece Vertical Takeoff Horizontal Landing (VTHL) vehicles, will win out in the end due to the economics of the designs.

SpaceShipOne is a remarkable research craft, and deserves its place in history. However, it is not anywhere near as efficient or effective at regular suborbital tourist runs as a VTHL RLV.

_________________
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
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post    Posted on: Sat May 22, 2004 6:15 pm
i get your point, still:
"... a ground-launched ship needs to be twice the weight of one launched at 50kft altitude"
http://www.scaled.com/projects/tierone/New_Index/data_sheets/html/lith_space_one_p2.htm

it's not the best link but it's a well known fact that most of the fuel/energy is used at the beginning of a rocket burn

the way i see it wk is just the same as a stage1 rocket is for the other contestants (except for armadillo i guess) with some added benefits, especially safety, but also launch conditions (a wider launch window), mobility, and almost no need for specialist infrastructure (uses normal airport runways). these are all costcutters and/or business advantages imo

the argument about needing a bigger/different wk for a bigger/different ss1 holds true for any staged rocket as well (if you want a bigger second stage you will need a bigger first stage)

the fuel pump argument sounds slightly outdated to me but even if it holds true (and to some degree i agree it does) i think it's a minor weight gain/disadvantage as opposed to any advantages (but that's my own highly subjective belief of course)

as to the need for not only strenght but stiffness i think this is a blessing in disguise, making for an overall safer vehicle. since wk/ss1 are all composite materials i think we can discard the weight issue until someone builds an all composite material two-stage rocket (at least none among the current competition is doing this)

i'm sure we still hold different opinions but i can completely understand your point of view and it was nice to see your reasoning

there is something that makes me wonder: is armadillo really going for a singlestage rocket? that seem even less efficient than a staged rocket design (even though it is very cool) unless they begin *ahem* aerospike development :wink:


Back to top
Profile
Moderator
Moderator
avatar
Joined: Mon Feb 09, 2004 4:01 am
Posts: 747
Location: New Zealand
Post    Posted on: Sun May 23, 2004 9:45 am
Single Stage is easy enough if you're not going to orbit.

Also SS1 uses pressure for the oxidiser.

Solids do not need any pumping or pressure at all.

For SS1 to become really efficent, the solid fuel needs to be "catridgeized".

If you have two white knights, a single SS1 can hop back and for easily between two distant locations.

_________________
What goes up better doggone well stay up! - Morgan Gravitronics, Company Slogan.


Back to top
Profile ICQ YIM
Space Station Commander
Space Station Commander
User avatar
Joined: Mon Oct 06, 2003 9:22 pm
Posts: 844
Location: New York, NY
Post    Posted on: Sun May 23, 2004 5:03 pm
i wonder if ss1, instead of feathering immediately, could just glide down from 100km to the point where they want to go. i can't think of any good reason why not, though you may have to boost slightly off vertical in the direction you want to go in order to keep going that way once you're in space.

_________________
Cornell 2010- Applied and Engineering Physics

Software Developer

Also, check out my fractals


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Wed May 19, 2004 12:13 am
Posts: 35
Post    Posted on: Sun May 23, 2004 8:10 pm
I thought the whole reason they feathered was to slow the ship on re-erntry... granted, not as difficult from sub orbit, but would there be enough heat to cause potential damage to the airframe if it didn't feather?

_________________
Only in darkness, the light. Only in silence, the word. Only in dying, life. Bright, the hawk's flight, on the empty sky.


Back to top
Profile
Spaceflight Participant
Spaceflight Participant
User avatar
Joined: Thu Apr 01, 2004 1:15 am
Posts: 79
Location: Auckland, New Zealand
Post    Posted on: Mon May 24, 2004 1:10 am
I just wanted to add another facet to this conversation.

It's an idea foreign to many of us who dream of commercialising space.

What if Scaled aren't interested in commercialisation? Haven't Burt's other projects been related to achieving some goal or being the first to do something?

Doesn't it make sense then to assume that this is the basis behind the Scaled entry into the Ansari X-Prize?

The question of Paul Allen's involvement confuses things, but I just thought I'd mention it. After many test flights for more data (possibly useful in future projects) SS1 might be sent to a museum and the plans locked in a basement somewhere.


Back to top
Profile WWW
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post    Posted on: Mon May 24, 2004 1:36 am
accoording to scaled they do feathering for both:
- creating a very high drag ratio, i.e. it starts slowing down earlier so the top return speed is lower, which means a lower maximum heat which in turn means less need for heatresistant materials. think of it as a kind of mechanical ballute/parachute
- selfrighting the vehicle automatically as a result of the drag, very nice from a safety (blackout and vertigo are "easily" survivable), and complexity view (no dependency on computers in the way "the flying brick" is)

i suspect ss1 is made to be able to land without feathering as an emergency landing, probably with damages but without serious injuries.


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Mon Oct 06, 2003 9:22 pm
Posts: 844
Location: New York, NY
Post    Posted on: Mon May 24, 2004 7:56 pm
i was thinking more along the lines of launching at an angle such that the ship would travel a very long ways above the atmosphere, then could feather and go down when it gets to where it's headed.

_________________
Cornell 2010- Applied and Engineering Physics

Software Developer

Also, check out my fractals


Back to top
Profile
Space Walker
Space Walker
avatar
Joined: Tue May 18, 2004 4:25 pm
Posts: 122
Post    Posted on: Mon May 24, 2004 9:25 pm
TerraMrs wrote:
i was thinking more along the lines of launching at an angle such that the ship would travel a very long ways above the atmosphere, then could feather and go down when it gets to where it's headed.

are you thinking of a let's say 45° launch angle from the white knight? i was surprised when i saw they do a fully horizontal launch and think they could launch at an angle if they want to
http://www.scaled.com/projects/tierone/New_Index/photos/images/1024/drop_ext_vid_1024.jpg


Back to top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 21 posts ] 
 

Who is online 

Users browsing this forum: No registered users and 2 guests


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