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#51 2005-02-20 16:13:19

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

RLV - Reuseable Launch Vehicle, which I classify as having no signifigant expendable componets, and returning all componets near the launch site that can be flown again without signifigant inspection/refurbishing.

GCNR - Gas Core Nuclear Rocket, a beautiful idea, and the best hope for Mars colonization or manned outter-planets exploration without fusion energy.

AltSpace - Alternative Space Companies, private companies that build space ships that are not the established aerospace giants (SpaceX, Scaled Composits, etc).
---
"The laws of physics apply to both... the innovation and cleverness [meaning, I assume, invention and engineering] which you give short-shrift will be able to overcome the above objections"

No they won't, because no amount of cleverness can change the laws of physics. "Cheap space ships" are not possible with today's technology. You would need a revolutionary new technology that changes everything, which will itself not come cheaply.

You would need something like a regenerative scramjet (not a regular one), an air-augmented integrated rocket engine, a metastable superfuel, arbitrary-length anisotropic CNT composits... something that changes the game. Without such a change, AltSpace companies are forced to play by the same rules as everyone else, and they will lose.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#52 2005-02-20 17:01:02

J.J. Moesker
InActive
From: The Netherlands
Registered: 2005-01-27
Posts: 19

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Prior to advocating a new launch concept one must first ask him self if there is a real need for the product. High launch cost are often stated as the factor that limits commercialization of space. This might be the case in the long term but for the current space market there is no need to be cheap. The magic dollar per kilogram figure does not dictate the chose of a launcher. Reliability and time to launch are the real cost drivers.

The founders of SpaceX saw this need and could create a consistent business case, attracted investors and actually sat through the whole development cycle of their product. They deserve all the credit for there effort to develop a really private funded launcher. During the constellation boom there where a lot of companies who thought they could do it. Yet only one survived and has a launcher on the pad. Too much ambition is deadly for a startup industry.

The Falcon I market segment is a growth market. Currently small payloads piggyback on the big boosters or are launched on converted ballistic missiles. Capacity is limited and other start-up companies will likely follow in SpaceX footsteps. Their technology will be based on ‘simple’ expendable vehicles. These rockets will be using a new (cheap) type of fuel pump being currently developed. The private funded industry that will develop around this segment will mature and start expanding their horizon. Parallel to these small launch companies, others are developing suborbital rocket planes for leisure and point to point travel. Who knows what will happen when both horizons converge.

At the moment it’s too early for big projects, the industry and market needs time to start snowballing. I find it great that private funded companies are really putting something together, how small it might even look.


With both feet on the ground you won't get far.

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#53 2005-02-21 06:41:04

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,428

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Well here is an example that I am not sure if we count them it the normal space camp or in the altX camp. It is part of a missile defense system test that
Tim Bradner: Wake up, Pentagon: Alaska rocket business taking off from a Kodiak Launch Complex, in Alaska of all places. Even further north than the Russians. But would that make that a better place to service and to resupply the ISS than from Florida would be my question?

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#54 2005-02-21 10:05:04

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,428

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

The safety dance

Late last year the nascent commercial suborbital spaceflight industry won a major victory on Capitol Hill when Congress passed—almost literally at the last minute—HR 5382, the Commercial Space Launch Amendments Act (CSLAA) of 2004.

While critics like Oberstar remain unconvinced, such a rationale—which equates suborbital spaceflight to risky hobbies like skydiving and mountain climbing rather than commercial aviation—goes a long way towards explaining the industry’s preferences for regulation.

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#55 2005-02-21 11:48:27

deagleninja
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From: USA
Registered: 2004-04-28
Posts: 376

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

No they won't, because no amount of cleverness can change the laws of physics. "Cheap space ships" are not possible with today's technology. You would need a revolutionary new technology that changes everything, which will itself not come cheaply.

You would need something like a regenerative scramjet (not a regular one), an air-augmented integrated rocket engine, a metastable superfuel, arbitrary-length anisotropic CNT composits... something that changes the game. Without such a change, AltSpace companies are forced to play by the same rules as everyone else, and they will lose.

Actually, I agree. You either need something that 'changes the game', as you put it, or an incredibly complex scramjet that is beyond the scope of the private industry.

What I see most likely happening is something similar to Scaled's SS1 effort in the sense that TWO RLVs are employed in unison. Afterall, WhiteKnight did most of the hard work for SS1 or it never would have reached that altitude.

Space travel difficulties stem from many things, but perhaps the most challenging is dealing with two different environments. A single stage RLV is so daunting because you must reach incredible speeds in a high friction / high drag environment. Rocket efficency is seriously slashed by not only fighting gravity, but also by shearing forces and resistance in general. Ask yourself, would you use a rocket to travel from ocean floor to surface, or would you just float?

The Canadian Arrow team is on the right track with their balloon assisted concept. Unfortunately, they are seriously underfunded. On the upside, high altitude ballons and true lifting bodies show incredible promise and are experiencing a revolution. In theory, it is even possible to reach orbit with a lifting body, as Air Force research has shown.

In summary, leave rockets to space, its their natural environment. Take advantage of the atmosphere with scramjets and high altitude balloons, its their natural environment.

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#56 2005-02-21 13:16:35

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

No, you misunderstand what I mean by "the rules" deagle

White Knight doesn't change the rules, because it is still using traditional propulsion concepts. Since relativly cheap jet planes cannot reach speeds or altitude anywhere near orbit, then they hardly help at all for reaching orbit.

White Knight/SSO and Canadian Arrow and the other X-Prizers are special cases, where they don't want to reach orbit, they only want to reach high altitudes. Getting into orbit is not hard because of gaining altitude, it is hard because of gaining velocity, you need to be going Mach Twenty Five to maintain a stable orbit. White Knight or a high altitude balloon contribute almost nothing to your velocity, only your altitude.

Getting up high is easy, but getting enough speed to reach orbit is hard. Balloons and low-performance carrier planes simply don't contribute much to the velocity, so they don't change the game at all.

Rockets today are great because you can simply point them at an angle with a shallow arc trajectory and they use their sheer brute force to reach the high mach numbers to enter orbit. A lift-body vehicle would be pretty close to the ideal RLV spaceplane design, but only a very advanced regenerative scramjet would permit SSTO flight.

It is possible that a large supersonic carrier planes with high-end jet engines with a second stage spaceplane powerd by chemical rockets could reach orbit, but development would be very expensive because of the size, performance, and seperation challenges.

Another option I wonder about is taking the DC-X concept, an SSTO vertical launch rocket, and equip it with an air-augmented rocket engine. The basic idea is to intentionally admit air compressed by the rockets' forward flight to increase the effectiveness of the rocket engine. I think a concept like this was investigated for the old NOVA rockets to increase performance... If you could substantially increase the performance of a DC-X style rocket, then it would be a more reasonable size for a medium lifter.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#57 2005-02-21 13:53:35

clark
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Registered: 2001-09-20
Posts: 6,374

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

If you could substantially increase the performance of a DC-X style rocket, then it would be a more reasonable size for a medium lifter.

pssst, hey GCN, the DC-X/Y program, prior to cancellation, this is what they were doing. Shhh. Don't spread it around.  big_smile

How about this... a modified DC-X that utilizes a two stage launch?

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#58 2005-02-21 15:07:54

Ad Astra
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Registered: 2003-02-02
Posts: 584

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

The problem with a two-stage DC-X type vehicle is getting the booster back to the launch site.  It would need significant glide range, which probably isn't possible with the DC-X "lifting capsule" approach.

Buzz Aldrin's StarBooster concept (a winged, reusable rocket) envisioned gliding back to base with wings if the boosters separated at Mach 3 or slower.  For speeds between Mach 3 and Mach 6, both wings and jet engines were needed.

The reusability of the booster will have to be determined by the trajectory, separation velocity, and separation altitude.  The requirements for a booster's return have traditionally been quite different from those for an orbital vehicle coming back to earth.  The result has been very different designs being used for orbiter and booster.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#59 2005-02-21 15:11:06

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

I don't mean taking the basic DC-X concept and improving the performance of exsisting aerospike engines like they were doing... I mean do something completly new, a hybrid rocket/ramjet engine that would leverage the air as "free" reaction mass. Of course, developing such an exotic arrangement wouldnt be cheap.

http://www.astronautix.com/lvs/novr10e2 … vr10e2.htm

How about a modified conventional rocket engine with a 620sec Isp?

Given that increase in performance, then the scarry-tight mass margins of the DC-X become much more realistic, or a signifigantly smaller vehicle could be built that could skirt the possible for an entirely private (but big) effort. Perhaps add conventional jet turbine engines for extra hover loiter, and put the crew capsule in the front for emergency escape.

Two stage DC-X? No way, that defeats the huge advantages of the DC-X concept. Its also called the "Kistler KH-1" and has been by and large a dismal failure.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#60 2005-02-21 15:11:26

clark
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Registered: 2001-09-20
Posts: 6,374

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

What about a launch and splash for the booster? Retrieve by boat.

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#61 2005-02-21 15:14:10

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

No no, the stage must return near the launch site and be reliable enough to fly without more then a quick check. Water landing makes recovery difficult and the sea water can damage the rocket.

Dry landing only.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#62 2005-02-21 15:17:04

clark
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Registered: 2001-09-20
Posts: 6,374

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

If you have enough of a forward supply, then the time for refurbish dosen't matter. Something like the rationale of the Shuttle, but executed in a more effecient manner...

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#63 2005-02-21 15:43:53

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Then too many of your rockets spend too much of their time on the ground, and you'll be paying dearly for them, just like airplanes only worse.

Also, having a "fuel and fly" level of reliability demanded by rapid turnaround (which the DC-X could have achieved in theory) then the safety & insurance of the scheme will be much easier on the bottom line.

*envisioning...*

A DC-X style rocket, fueled by liquid oxygen and slushed hydrogen, being a little bit wider to accomodate the air-augmented rocket engine. About half-way up the fuselage, a pair of ducts on either side of the vehicle would run through (or around) the length of the rocket to the engine nozzle and increase the engines' performance. The ducts would have retractable doors to cover them during reentry.

On the two quarters of the vehicle between the ducts, one would be extra shielded for reentry thermal stress, and the other side would include the cargo bay/crew cabin. The two models would be differentiated by one flying cargo and the other crew, and the crew module could detach in an emergency straight up and away from the vehicle. It would also be reentry-capable on its own and have floatation capability for water landing.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#64 2005-02-21 20:35:59

Ad Astra
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Registered: 2003-02-02
Posts: 584

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

the stage must return near the launch site and be reliable enough to fly without more then a quick check.

I guess this means Integrated Vehicle Health Management (IVHM) is a prerequisite for RLV's.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#65 2005-02-22 07:22:35

deagleninja
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From: USA
Registered: 2004-04-28
Posts: 376

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Ok.....I'll leave the hard physics to you to work out, but how wouldn't raising a spacecrafts launch platform to 60 miles or more help? You are talking about a tremendous difference in air pressure / resistance. Also, the higher your orbit the slower the required orbital velocity right?

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#66 2005-02-22 07:31:24

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,428

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

I'm not sure but if so then building a space port in the Hymalayas would foot the bill for a modest increase of launch altitude.

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#67 2005-02-22 10:55:59

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Ok.....I'll leave the hard physics to you to work out, but how wouldn't raising a spacecrafts launch platform to 60 miles or more help? You are talking about a tremendous difference in air pressure / resistance. Also, the higher your orbit the slower the required orbital velocity right?

Why not? Because as I said, getting into orbit isn't about altitude, its all about velocity.

Why don't things fall out of orbit? Because they are moving so fast that they fall around the Earth continuously.

The reason why a balloon launch at high altitude won't help is because most of the energy needed to get into space isn't in reaching altitude, that is only a small percentage of it. Most of the energy, and hence fuel, and hence size is needed to reach the Mach 25 of orbital velocity. If you launch off of a balloon, you are only saving enough fuel to reach that altitude, which is itself only about 1/3rd to 1/4th the height to orbit. A fraction of an already small percentage... This is why there are no small orbital vehicles.

Air resistance isn't a huge factor for rockets, which is bascially nil after the first minute or two of the acent. Velocity is everything, altitude is less important.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#68 2005-02-24 17:26:42

publiusr
Banned
From: Alabama
Registered: 2005-02-24
Posts: 682

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Space Dev's idea seems more realistic.

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#69 2005-02-24 19:04:32

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

SpaceDev? Please, they are piddling around with puny hybrid rockets. Wake me when they decide to get with the program and use liquid fuels.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#70 2005-02-25 15:11:13

deagleninja
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From: USA
Registered: 2004-04-28
Posts: 376

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

GCNR, I'm afraid I didn't make myself as clear as i could have, my appologizes. I understand that in the effort to reach orbit velocity is more important than altitude. What I was propossing is a bouyant spacecraft that can leave 99.9% of the atmosphere behind it. At these incredible altitudes it should be possible to build up the needed velocity to orbit the earth overtime. To achieve this I had a much stronger ion engine in mind. Thoughts?

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#71 2005-02-25 16:15:27

publiusr
Banned
From: Alabama
Registered: 2005-02-24
Posts: 682

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

On Page 55 of POP SCI there is a nice stack.

Admittedly, Space Dev is probably not up to the task.

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#72 2005-02-25 17:49:12

J.J. Moesker
InActive
From: The Netherlands
Registered: 2005-01-27
Posts: 19

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

GCNR, I'm afraid I didn't make myself as clear as i could have, my appologizes. I understand that in the effort to reach orbit velocity is more important than altitude. What I was propossing is a bouyant spacecraft that can leave 99.9% of the atmosphere behind it. At these incredible altitudes it should be possible to build up the needed velocity to orbit the earth overtime. To achieve this I had a much stronger ion engine in mind. Thoughts?

I’m not GCNR, but if may be so frank to respond. Your concept is interesting yet I see some pitfalls. One would require a large, lighter than, air ‘balloon’ to float a substantial payload mass to the edge of the atmosphere. Even at those heights the atmosphere is thick (heavy) enough to create substantial amounts of drag. To reach orbit you must obtain a velocity of approximately Mach 25! Even small sattelites in LEO experience substantial aerodynamic loads and heating at heights of > 200 km. A blimp of such size would not sustain the aerodynamic loads involved. Furthermore there is the fundamental problem of the ‘lifting’ mass inside the balloon which also needs to be accelerated.

Yet there might be an application for floating ‘space ports’. One could imagine a hotel floating sub-orbital at the edge of space. Although you won’t experience weightlessness, the view would be absolutely stunning. Getting there could be a problem though. If the size permits, the station could use a landing/docking strip. Or even use smaller balloons resistant to harsh lower atmosphere weather conditions penndeling up and down. Now there is nice SF idea.

Dreaming up new concepts is not difficult. New RLV concepts are published each year in the various Journals. All of them are technological feasible, yet none of them are being build. Why is this so? That would be an interesting question to discuss.


With both feet on the ground you won't get far.

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#73 2005-02-25 18:04:11

deagleninja
Member
From: USA
Registered: 2004-04-28
Posts: 376

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Thanks for the reply. I understand that even at those altitudes there is a LOT of drag, especially on something this large. So to counter that drag, why wouldn't it be possible to flatten out your 'balloon' into a solar sail? Couldn't it be possible?

In fact, couldn't small ion engines help pull it into a sail shape, greating increasing the surface area of our balloonsail?

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#74 2005-02-25 19:20:17

Euler
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From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Both drag and gravity apply to solar sails just as much as they apply to other matter.  I don't see how changing your balloon into a sail will help you.

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#75 2005-02-25 19:39:14

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Richard Branson / Rutan Team Up For Orbital Flight - Five year plan to put tourists in space?

Ohhhhh you mean one of those "dark sky" balloons as launch vehicle... I was thinking you ment using a conventional chemical rocket and launching off a balloon to try and save on fuel.

A solar sail won't do you a whole lot of good, since you'll be flying either parallel or under the direction of the sunlight, so it anything the light pressure would push you back down.

I think that without an extremely light weight ion engine and an extremely large balloon, that such a vehicle would have too much trouble with drag and not make it to orbit easily enough.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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