BEFORE КЛИПЕР IT WAS DELTA-CLIPPER

[ronatu]

Ну раз это вызываeт интерес то...

Back in 1996, a man named John Whitehead wrote a paper (AIAA96-3108) in which he showed that the weights of typical launch vehicle stages had not changed substantially over time. If tank weights have not improved in fifty years, it's best not to assume you can dramatically beat history. Whitehead also noted that tank weight as a function of propellant volume was essentially constant over a wide range of tank sizes, from a few tens of thousands of pounds to well over a million pounds. He highlighted the fact that the weight of a tank capable of holding a given quantity of propellant was directly proportional to the propellant density, because the tank weight was almost completely dependent on the volume of the propellants.

Whitehead also addressed the other major weight contributor in a typical stage, the rocket engines. For dense propellant combinations such as LOX/kerosene, the engine typically weighs 1% of the thrust (for a "thrust-to-weight ratio" or T/W of 100); for lower density propellants such as LOX/LH2, the figure is in the neighborhood of 2% (T/W of 50). A third but smaller contributor is the propellant pressurization system weight. This system provides the gas pressure that is used to force the propellants through the piping of the feed system and into to the turbopumps which feed the engines. Finally, there is the weight of the residual propellants that remain in the tanks or the feed lines and are unused by the engines.

The remaining structural elements in the stage, the engine thrust structure, which transmits the thrust of the engines to the loaded propellant tanks, and the payload or upper stage support structures were not considered by Whitehead because these tend to be much more design-specific. The purpose of his paper had been simply to point out which structural elements of a typical launch vehicle stage were more or less mature in terms of achievable weights, and which were likely to benefit from better engineering in order to reduce their weights. Whitehead's main concern was the problem of single-stage vehicles. For a single-stage vehicle, the rocket equation - MR=e(Velocity/ISP*32.2) - tells you, for a given engine ISP (i.e. jet exhaust speed divided by acceleration due to gravity) and a total desired velocity change, what fraction of the initial stage mass would achieve that velocity change.

The mass ratio, MR, is the ratio of the initial mass of the stage to the final mass after all of the propellants necessary to attain your desired velocity change have been burned. If that desired velocity change is equal to that required to go from zero at your launch point to orbital velocity, then it will tell you how much of that initial mass will reach orbit. Whitehead, by characterizing tank, engine, and propellant feed system weights as percentages of the total final or empty weight of the stage, provided a fairly accurate means of estimating how much weight could be allocated to the other structural and vehicle components, and more importantly, how much payload could be included. In other words, if you know the percentage of the final weight that must be allocated to the tanks, engine, and pressurization system, then you can determine how much is left for the other vehicle systems and the payload.

Considering the parametrics of a pressure-fed design, three factors must be considered that contribute to lower performance as compared to a turbopump-fed stage. The first is the greater weight of tanks strong enough to support the higher internal pressure needed to force the propellants all the way to the combustion chamber. Secondly, because this pressure is typically 5-10 times higher than the internal pressure required for a pump-fed stage, the weight of the gas used to pressurize the tank is also proportionately greater. Lastly, the engine specific impulse (ISP) is also typically lower for a pressure-fed stage because the engine chamber pressure tends to optimize at a lower value when the increased weight of the pressurization system and tanks is considered. The higher the tank pressure, the greater the weight of the tank and the pressurization system, which drives the design toward a low-pressure engine. Thus by eliminating the turbopumps - which are complex and expensive both to develop and to produce - the designer accepts higher weights and generally lower specific impulse.

Because of the high tank weight, pressure-fed vehicles have typically utilized dense propellants and lightweight pressurizing gases. For a typical pump-fed stage the tanks weigh approximately one percent of the weight of the propellants (for propellants with a density about the same as water). If the pressure in the tanks is increased by a factor of ten, one would expect the tanks to grow to about ten percent the weight of the propellants. To minimize this weight growth, high strength-to-weight materials are typically employed.

http://www.hobbyspace.com/AAdmin/archive/SpecialTopics/RocketCom/chap04page1.html

[Agent]

Композитный бак для ЖВ (большой размерности) в прошлом году прошел все тесты. 40 циклов без замечаний.
Это прямой наследник того, который не получился для программы Х-33, токо перешедший под бюджет NGLT. Тот же Нортроп его до ума и довел.
Нельзя говорить, что все деньги потрачены зря. Окромя материального выражения, необходимо копить тн "сумму технологий". Потом это "стреляет" - количество переходит в качество.
NGLT (Next Generation Launch Technology) - как раз для этого и был задуман.

[ronatu]

Композитный бак для ЖВ (большой размерности) в прошлом году прошел все тесты. 40 циклов без замечаний.
Это прямой наследник того, который не получился для программы Х-33, токо перешедший под бюджет NGLT. Тот же Нортроп его до ума и довел.
Нельзя говорить, что все деньги потрачены зря. Окромя материального выражения, необходимо копить тн "сумму технологий". Потом это "стреляет" - количество переходит в качество.
NGLT (Next Generation Launch Technology) - как раз для этого и был задуман.

The Next Generation Launch Technology program sought to develop and mature innovative technologies based on these predecessors.The program is pursuing new research in the areas of propulsion, structures, vehicle systems, and ground and flight operations. Overall, the NGLT program focused on the development of new technologies that provide NASA the means of improving safety and lowering launch costs.

NASA's Booster Engine Prototype (BEP) effort seeks to deliver a large-scale, prototype liquid-oxygen/kerosene engine system that will enable development of full-scale, flight-ready engines for a next generation reusable booster.

The Integrated Powerhead Demonstrator (IPD) project — which seeks to double the capability of booster engines providing access to space — is contributing new engine technologies for NGLT and Department of Defense propulsion research.

The X-43A, the first demonstrator vehicle in NASA's "Hyper-X" series of experimental hypersonic ground and flight test vehicles, will demonstrate "air-breathing" engine technologies for future hypersonic aircraft and/or reusable space launch vehicles, achieving speeds above Mach 5, or five times the speed of sound.

The Turbine-Based Combined Cycle (TBCC) engine project seeks to deliver a Mach 4+ hypersonic propulsion system in this decade. Prime among its enabling technologies: the Revolutionary Turbine Accelerator (RTA), intended to demonstrate high mach turbine and TBCC propulsion for space access.

The Rocket-Based Combined Cycle (RBCC) engine system is for ground demonstration in this decade. The Integrated System Test of an Air-breathing Rocket (ISTAR) project is NASA's first flight-type system development and ground test of an RBCC propulsion system.

The RS-84 is one of two competing efforts now under way to develop an alternative to conventional, hydrogen-fueled engine technologies. The RS-84 is a reusable, staged combustion rocket engine fueled by kerosene — a relatively low-maintenance fuel with high performance and high density, meaning it takes less fuel-tank volume to permit greater propulsive force than other technologies. That benefit translates to more compact engine systems, easier fuel handling and loading on the ground, and shorter turnaround time between launches. All these gains, in turn, reduce the overall cost of launch operations, making routine space flight cheaper and more attractive to commercial enterprises.

Next Generation Launch Technology (NGLT) architecture definition efforts required innovative system analysis tools to determine the impact of critical technologies on the overall launch system infrastructure. Next generation of launch systems will require high overall vehicle payload mass to lift-off mass ratios, propulsion systems which deliver higher thrust to engine weight ratios, increased trajectory-averaged specific impulse, reliable overall vehicle systems performance, and extended reusability in order to achieve cost and crew safety goals.

[ronatu]

Композитный бак для ЖВ (большой размерности) в прошлом году прошел все тесты. 40 циклов без замечаний.
Это прямой наследник того, который не получился для программы Х-33, токо перешедший под бюджет NGLT. Тот же Нортроп его до ума и довел.
Нельзя говорить, что все деньги потрачены зря. Окромя материального выражения, необходимо копить тн "сумму технологий". Потом это "стреляет" - количество переходит в качество.
NGLT (Next Generation Launch Technology) - как раз для этого и был задуман.

The Next Generation Launch Technology program sought to develop and mature innovative technologies based on these predecessors.The program is pursuing new research in the areas of propulsion, structures, vehicle systems, and ground and flight operations. Overall, the NGLT program focused on the development of new technologies that provide NASA the means of improving safety and lowering launch costs.

NASA's Booster Engine Prototype (BEP) effort seeks to deliver a large-scale, prototype liquid-oxygen/kerosene engine system that will enable development of full-scale, flight-ready engines for a next generation reusable booster.

The Integrated Powerhead Demonstrator (IPD) project — which seeks to double the capability of booster engines providing access to space — is contributing new engine technologies for NGLT and Department of Defense propulsion research.

The X-43A, the first demonstrator vehicle in NASA's "Hyper-X" series of experimental hypersonic ground and flight test vehicles, will demonstrate "air-breathing" engine technologies for future hypersonic aircraft and/or reusable space launch vehicles, achieving speeds above Mach 5, or five times the speed of sound.

The Turbine-Based Combined Cycle (TBCC) engine project seeks to deliver a Mach 4+ hypersonic propulsion system in this decade. Prime among its enabling technologies: the Revolutionary Turbine Accelerator (RTA), intended to demonstrate high mach turbine and TBCC propulsion for space access.

The Rocket-Based Combined Cycle (RBCC) engine system is for ground demonstration in this decade. The Integrated System Test of an Air-breathing Rocket (ISTAR) project is NASA's first flight-type system development and ground test of an RBCC propulsion system.

The RS-84 is one of two competing efforts now under way to develop an alternative to conventional, hydrogen-fueled engine technologies. The RS-84 is a reusable, staged combustion rocket engine fueled by kerosene — a relatively low-maintenance fuel with high performance and high density, meaning it takes less fuel-tank volume to permit greater propulsive force than other technologies. That benefit translates to more compact engine systems, easier fuel handling and loading on the ground, and shorter turnaround time between launches. All these gains, in turn, reduce the overall cost of launch operations, making routine space flight cheaper and more attractive to commercial enterprises.

Next Generation Launch Technology (NGLT) architecture definition efforts required innovative system analysis tools to determine the impact of critical technologies on the overall launch system infrastructure. Next generation of launch systems will require high overall vehicle payload mass to lift-off mass ratios, propulsion systems which deliver higher thrust to engine weight ratios, increased trajectory-averaged specific impulse, reliable overall vehicle systems performance, and extended reusability in order to achieve cost and crew safety goals.

[Зомби. Просто Зомби]

Что написано-то:

"The Rocket-Based Combined Cycle (RBCC) engine system is for ground demonstration in this decade. The Integrated System Test of an Air-breathing Rocket (ISTAR) project is NASA's first flight-type system development and ground test of an RBCC propulsion system."

Кто бы перевёл
А то мне чё-то кажется, кажется, кажется... что я это уже где-то встречал... или видел... или слышал... что-то такое... эдакое :wink:  :mrgreen:

[Зомби. Просто Зомби]

Yandex дает первую ссылку:

http://www.indel.ru/a/air_breathing_rocket.html

Во первых строках:

Air-breathing rockets have the potential to dramatically lower launch costs and may make space lots more accessible to normal people.

[Зомби. Просто Зомби]

Плохо, что у меня с английским фигово

[Agent]

Зомби, не берите в голову. NGLT закончен в 2004. Проекты или закрыты  или переданы под Эксплорейшен НАСА или ДоД. До начала постройки лунной базы (окончания разработки), особых денег от НАСА не стоит ожидать на подобное.

Air-breathing Rocket - это ща НАВИ разрабатывает, наследие Х-43 - ЭйрФорс. Деталей, соот-но, не будет.

[Зомби. Просто Зомби]

А!
То есть, "чисто концептуальная разработка"?

Всё равно радует, что крыльев нет :mrgreen:
Хотя форма и аэродинамическая :wink:

[foogoo]

вот с катринками  
http://www.nasaexplores.com/show2_articlea.php?id=01-047

Why change the way a rocket is powered? If you don't have to carry the oxidizer on the rocket, you can reduce the weight by up to 50 percent. Lighter vehicles are both cheaper to operate and easier to launch. NASA's goal is to reduce the cost of spaceflights by a factor of 100, and this is a way to help achieve that goal.

It's a little more complicated than that, of course. Air-breathing rockets are more technically called combined cycle rocket engines because they employ both conventional rockets and air-breathing technology. The initial push comes from a rocket; then ramjets start the air-breathing process (visualize ramming the air through the vents into the combustor), and when the speed gets up to Mach 6, the scramjet takes over (scram jets use supersonic combustion; ram jets use subsonic combustion). Once the speed reaches Mach 15, the scramjets are turned off, the rockets go back on, and the vehicle goes into orbit.

Conventional rockets launch vertically— straight up— to exit the atmosphere as quickly as possible. Air-breathing rockets, because they need oxygen from the atmosphere, stay in the atmosphere as long as they can to inhale as much oxygen as possible. Rather than launching vertically, air-breathers can be launched either vertically or horizontally. They fly much like an airplane, cruising at high altitudes, taking in oxygen until the proper speed is reached for orbit.

[Agent]

Угу. И пока оно не выползет назад с военных лабораторий на свет общественности (как это с Х-43 произошло, уползшим назад впоследствии) - эти концепции дополнительно представляют собой чисто академический интерес. По крайней мере для меня.
Лично мне гораздо интереснее свинцовая пластина на месте БЧ в Х-43А. Потому как этой пластине гораздо больше шансов стать ПН. Ну и всякие прямые трансляции, детальные описания и тд.

[pkl]

Спасибо. Но меня всё же интересует вопрос - почему классический одноступенчатый многоразовый [/size]носитель всё никак не получается?

Потому что вес! Сделать такой аппарат с требуемой сухой массой при нынешнем уровне техники невозможно.

Ясненько! Т.е., те кто говорят, что возможно - или заблуждаются, или э-э-э вводят в заблуждение? И ещё, как я понимаю, против многоразового одноступенчатого носителя работает экономика - невыгодно на нём запускать, как и на Шаттлах?
А если такой вариант - сделать из многоразового одноступенчатого носителя вертикального взлёта/посадки многоразовую первую ступень. А сверху добавить небольшой /10-15% от стартовой массы системы/ доразгонный блок, ну там, твердотопливный или жидкостный с вытеснительной подачей - это изменит положение вещей?
И ещё - если НПО Лавочкина сделает наконец НТУ - эта технология позволит создать одноступенчатый многоразовый носитель?

[X]

dfgdfgd

[STEP]

Сделать то многоразовую одноступенчатую машину можно. Только вот она:
во первых не будет экономически выгодной, т.к. будет доставлять на орбиту слишком малую ПН,
во вторых она не будет многоразовой, т.к. будет разбиваться в каждом первом.
Сейчас вон многоступенчатые то системы полностью многоразовыми сделать не могут, а вот одноступенчатым вдруг закон не писан.

[ronatu]

Japan's RVT (Reusable Vehicle Test) rises vertically a short distance and then returns for landing.

From:

http://www.hobbyspace.com/Links/RLV/RLVTable.html

[ronatu]

гз

[Shin]

гз

Ну... Вообще-то искусственное поднятие темы попахивает санкциями. Если никакой новостной информации или мысли нема, то занятие это уголовно-наказуемое

[чайник17]

Вот в этом видео:

около 1:50 наткнулся на интересное утверждение:
баки кислорода DC-XA были сделаны в России, из "литиевого" сплава.
Может кто знает, какое предприятие их делало? В мурзилке ещё написано:

the Russian-made tank was poor quality, had "16-inch/40.6-cm long weld defects, and there were other issues that, according to U.S. standards, would prevent it from flying."

что баки были из 1460 и дерьмовые.  

[Дмитрий В.]

Вот в этом видео:

около 1:50 наткнулся на интересное утверждение:
баки кислорода DC-XA были сделаны в России, из "литиевого" сплава.
Может кто знает, какое предприятие их делало? В мурзилке ещё написано:

the Russian-made tank was poor quality, had "16-inch/40.6-cm long weld defects, and there were other issues that, according to U.S. standards, would prevent it from flying."

что баки были из 1460 и дерьмовые.  

Делала, насколько знаю, "Энергия". И не из "литиевого", а алюминий-литиевого сплава. 01460 оптимизирован для работы при криогенных температурах. 16-дюймовый непровар - это фигня. Для блока Ц сварочные дефекты допускались, емнип, на 15% длины сварочных швов.
 :wink:

[чайник17]

16-дюймовый непровар - это фигня. Для блока Ц сварочные дефекты допускались, емнип, на 15% длины сварочных швов.
 :wink:

А что так плохо-то? Не смогли разработать нормально свариваемый сплав с близкими характеристиками? НАСА вот пишет про свой 2195 что он замечательно сваривается:
http://www.nasa.gov/centers/marshall/pdf/113020main_shuttle_lightweight.pdf
2195 заметно плотнее 01460, но вроде и прочнее (предел текучести выше).