minotaur-4, 20/04/2010 HTV

[Имxотеп]

Насколько можно судить по этой и этой картинкам, 9-ая минута после старта как раз соответствует первому "нырку" в атмосферу. Либо система управления не удержала аппарат, либо прогорело ТЗП.

[Salo]

http://www.itar-tass.com/level2.html?NewsID=15059370&PageNum=0

Испытан аппарат, способный превысить скорость звука в 20 раз

23.04.2010, 22.11   

ЛОС-АНДЖЕЛЕС, 23 апреля. /ИТАР-ТАСС/. Пентагон осуществил первый испытательный полет аппарата, способного превысить скорость звука в 20 раз. Запуск гиперзвукового беспилотного аппарата /ГБА/ на ракете-носителе "Минотавр" был осуществлен в четверг с базы ВВС США Ванденберг в штате Калифорния. Об этом сообщило сегодня Управление перспективных исследовательских программ минобороны /ДАРПА/. ДАРПА и командование базы не говорят о том, насколько успешно прошло испытание, и не приводят другие подробности.

Согласно предоставленным ранее данным управления ГБА под названием "Эйч-Ти-Ви-2" разработан корпорацией "Локхид-Мартин". Проект является составной частью программы "Фэлкон", ставящей своей целью обеспечить министерство обороны США средством нанесения "быстрых и точных неядерных ударов по любой цели на планете в ответ на угрозы национальной безопасности Соединенных Штатов". Причем, речь идет о реагировании на возникновение таких угроз "в минимальные сроки или без предупреждения" вообще. ГБА задуманы в качестве альтернативы межконтинентальным баллистическим ракетам, оснащенным ядерными боеголовками, уточнили в ДАРПА.

Ракета-носитель "Минотавр" насчитывает четыре ступени, но для испытания собрана в трехступенчатом варианте. Программа полета предусматривала отделение ГБА от ракеты в верхних слоях атмосферы, потом спуск в режиме свободного парения над Тихим океаном в направлении Маршалловых островов со скоростью около 21 тыс км/час. Условная цель - севернее атолла Кваджалейн - расположена на расстоянии 4,1 тыс морских миль. "Эйч-Ти-Ви-2" должен был преодолеть их менее чем за 30 минут.

[flateric]

DARPA's HTV-2 Didn't Phone Home

Posted by Graham Warwick at 4/24/2010 10:57 AM CDT

DARPA says it lost contact with its HTV-2 hypersonic test vehicle 9min after launch of the dart-like glider atop a Minotaur IV Lite booster from Vandenberg. The agency's brief press release says the Minotaur successfully delivered its payload to the desired separation conditions and deployed the HTV-2, so telemetry was lost after the unpowered vehicle was released at the edge of the atmosphere.

One possibility is that a sheath of plasma that would form around the vehicle as it reentered the atmosphere at Mach 20-plus could have interfered with telemetry. But in an interview with Aviation Week before the flight, DARPA program manager Paul Erbland said the risk of ionized gases attentuating signals from the vehicle was "relatively modest", particulary at the high altitude the HTV-2 was deployed.

The release does not say what happened to the HTV-2 - the vehicle had a specially developed autonomous flight safety system designed to detect any deviation from the planned route and automatically terminate the flight.

The Lockheed Martin-built HTV-2 was supposed to fly 4,100nm across the Pacific in 30min in the first of two flights to demonstrate aerodynamic, thermal-protection, and guidance, navigation and control technology for a prompt global strike weapon able to fly 9,000nm in under 2 hours. The second flight is planned for 2011.

The sharp-edged, highly swept HTV-2 is designed to demonstrate long endurance at high speed by achieving an "unprecedented" hypersonic lift-to-drag ratio, much higher than the Space Shuttle's, and having a carbon-carbon aeroshell that provides thermal protection with minimal ablation, unlike a reentry-vehicle heat shield that burns off to shed heat.

Looking for success among the bad news, DARPA says the Minotaur executed "first of its kind" energy-management maneuvers before releasing the HTV-2. These were required, Erbland said, because even with just three Peacekeeper missile stages, the Minotaur IV Lite is more powerful than required. So the third stage maneuvered to bleed off energy before deploying the HTV-2 at the edge of the atmosphere.

Even then, he said, the booster would overshoot the desired insertion conditions by around 100,000ft, so the HTV-2 was programmed to reenter then pull up to the correct altitude to begin its hypersonic glide - which was planned to start around 200,000ft and Mach 20 and end around 100,000ft with the HTV-2 rolling inverted and pulling down into a hypersonic dive into the ocean off Kwajalein. Well, that was the plan.

Uncovered by the incomparable flateric on secretprojects.co.uk, this graphic from a December presentation by DARPA Tactical Technology Office director David Nyland suggests contact with the HTV-2 (on the yellow Mission A line) was lost somewhere between beginning reentry and starting its hypersonic glide.

Investigation of the telemetry failure is under way. But the question now is what this means for the second HTV-2 flight (red Mission B line above). This is intended to demonstrate the cross-range capability provided by the vehicle's hypersonic aerodynamic efficiency - and key to a prompt global strike weapon - involving sustained maneuvers beyond the simple S-turns planned for the first flight. It's more likely the second flight will have to be a repeat of the first.

Bill Sweetman wrote:
I talked to a longtime member of the hypersonic community at a conference in February, and he was fretting that the HTV-2, with sharp leading edges, was a high-risk approach. It's also the baseline for Prompt Global Strike. I expect that Boeing's alternative will be a biconic shape, more like the legendary AMaRV.

[Salo]

DARPA Investigates Hypersonic Glider Loss

DARPA Investigates Hypersonic Glider Loss

Apr 26, 2010
 
By Graham Warwick graham_warwick@aviationweek.com
Washington

Lockheed Martin and the Defense Advanced Research Projects Agency are investigating why contact with the first HTV-2 test vehicle was lost soon after launch on a mission to demonstrate technology for high-performance, long-endurance hypersonic flight.

The third stage of the Orbital Sciences Minotaur IV Lite booster successfully completed energy-management maneuvers, released its clamshell payload fairing and deployed the HTV-2 at the edge of the atmosphere, but telemetry signals from the hypersonic glider were lost about 9 minutes into the mission, DARPA says.

Launched from Vandenberg AFB, Calif. on April 22, the unmanned HTV-2 was planned to cross the Pacific and impact the ocean north of Kwajalein Atoll in the first of two flights to demonstrate technology for a prompt global strike weapon capable of flying 9,000nm in less than 2 hours.

After launch, the Minotaur's third stage was to execute maneuvers to bleed off energy before releasing the HTV-2, which was programmed to reenter the atmosphere then climb to the correct altitude to begin its glide to Kwajalein at around Mach 20.

Based on a mission timeline released by DARPA in December, the HTV-2 was between beginning reentry and starting its hypersonic glide when telemetry signals were lost. The agency says it is working to understand what happened to the vehicle.

Key technology-demonstration objectives for the flight included: a substantial increase in hypersonic aerodynamic efficiency, for long range; efficient thermal protection, to withstand sustained high temperatures; energy management, with autonomous precision flight control; and an autonomous flight termination system, for safety.

The first mission was to be a direct flight from Vandenberg to Kwajalein, with a series of S-turns to bleed off energy and collect aerodynamic data. The second flight, set for 2011, was planned to expand the envelope to higher velocity, up to Mach 25, and demonstrate cross-range maneuvering.

Data from the flight was intended to validate new design tools developed by DARPA and prime contractor Lockheed Martin. "The measure of success is collecting data to verify modeling and analysis tools that will open a new design space for high-performance, long-endurance maneuvering hypersonic systems," said DARPA program manager Dr. Paul Erbland in an interview before the mission.

The HTV-2 is a slender, highly-swept, sharp-edged delta with "unprecedented" aerodynamic efficiency for a hypersonic vehicle, said Erbland. The vehicle is designed to fly at a low angle of attack relative to other hypersonic vehicles. "Shuttle and similar vehicles fly at roughly 40°; HTV-2 is substantially below that," he said.

The single-piece, load-carrying carbon-carbon aeroshell is designed to withstand extended exposure to high temperatures with low recession, unlike the heat shields on reentry vehicles that burn off material to shed heat. But very high temperatures on the sharp nose and leading edges of the HTV-2 are expected to cause them to recede by 1-2in over the flight, Erbland said, "so it's important to understand how shape change affects aerodynamics and mass properties, then accommodate that in the guidance, navigation and control design."

Lockheed Martin and Carbon-Carbon Advanced Technologies fabricated the aeroshell by co-consolidating components during build-up into a single-piece structure, which was then installed over an insulated cocoon housing vehicle systems. "It's a tremendously efficient thermal protection system for high-altitude, high-speed flight," he said. "Instantaneous heat flux is not as high [as for a reentry vehicle], but over a long time the net heat load is huge and carbon-carbon radiates a large percentage back to space."

Extensive arcjet and wind-tunnel testing was conducted to benchmark the aero-thermal computational models used by Lockheed Martin to design the HTV-2. "Because temperatures on the nose and leading edges are so high, we do get recession. We have to accept the shape change and model the recession to understand the effect on mass properties and aerodynamics," Erbland said.

A key factor in aero-thermal design is the transition from laminar to turbulent flow over the vehicle, as boundary-layer turbulence increases drag and surface heating and drives heat-shield thickness. "In the past vehicle designers assumed the whole flight was turbulent, which caused us to overdesign the heat shield and carry excess weight," he said.

Transition prediction for previous hypersonic designs was based on correlation with existing data derived from reentry-vehicle and space shuttle flights, "[but] we didn't have a database for slender hypersonic lighting vehicles," Erbland said. As a result, DARPA, the U.S. Air Force and Lockheed Martin developed and used physics-based transition design tools for the first time in hypersonic vehicle development.

"We demonstrated the physical mechanisms driving transition are fundamentally different for this shape than for reentry vehicles or the shuttle," he said. The new tools predicted transition would occur earlier than expected using correlation-based analysis, so the HTV-2 was designed to carry additional energy into each maneuver to account for increased drag. "Transition behavior is sensitive to shape change. We have developed new analysis tools to fully couple that change to the heating and feed it back into the aerodynamics."

Autonomous guidance, navigation and control was designed to enable the HTV-2 to manage its energy and fly a precise flight path to a "very accurate" terminal location, said Erbland. After release, the vehicle was planned to navigate via a series of waypoints, managing its trajectory "to arrive with sufficient energy to get to the next one, plus a little extra in case the drag is higher than predicted."

DARPA concept

[flateric]

Pentagon's Mach 20 Glider Disappears, Whacking 'Global Strike' Plans
By Noah Shachtman  
April 27, 2010  |  4:49 pm  |  Categories: DarpaWatch

The Pentagon's controversial plan to hit terrorists half a planet away suffered a setback this weekend, after an experimental hypersonic glider disappeared over the Pacific Ocean.

In its first flight test. the Falcon Hypersonic Technology Vehicle 2 (HTV-2) was supposed to be rocket-launched from California to the edge of space. Then the HTV-2 would could screaming back into the atmosphere, maneuvering at twenty times times the speed of sound before landing north of the Kwajalein Atoll, 30 minutes later and 4100 nautical miles away. Thinly wedge-shaped for better lift, equipped with autonomous navigation for more precision, and made of carbon-carbon to withstand the assault of hypersonic flight, the hope was it could fly farther and more accurately at a lower angle of attack than other craft returning to Earth.

At least, that was the idea. Instead, nine minutes after launch, Darpa researchers lost contact with the HTV-2. They're still trying to figure out why. The agency says the flight test wasn't a total bust: The craft deployed from its rocket booster, performed some maneuvers in the air, and "achieved controlled flight within the atmosphere at over Mach 20," Darpa spokesperson Johanna Jones says.

But it's bad news for the Pentagon "prompt global strike" program — a burgeoning and hotly-debated effort to almost-instantly attack targets thousands of miles away. The Defense Department is pursuing three different families of technologies to accomplish the task. One is to re-arm nuclear intercontinental ballistic missiles with conventional warheads. But that runs the risk of accidentally triggering a response from another atomic power, who might mistake it for a nuke. A second effort is to build shorter-range cruise missiles than can fly at five or six times the speed of sound; that effort hit some recent turbulence when flight tests for the X-51 Waverider, scheduled for December 2009, were pushed until May 2010. Something like an armed version of the HTV-2 is the third choice.

"There's always a concern that a conventional warhead on an ICBM might be confused with a nuclear device - what can you do to prove otherwise?" Dr. Mark Lewis, the former chief scientist of the Air Force, tells Danger Room. "With a high lift vehicle, your trajectory would be so different that no one would likely confuse it with something more sinister."

Brian Weeden, a technology advisor for the Secure World Foundation, agrees. "This thing itself is not a weapon. But it's designed to lead to a precision strike weapon," he says.

But the first step is to figure out what went wrong over the Pacific. Darpa says its investigation is ongoing.

[Salo]

http://lenta.ru/news/2010/11/18/htv2/

США назвали причину неудачного первого полета гиперзвукового аппарата[/size]

Управление перспективных разработок министерства обороны США (DARPA) завершило расследование причин неудачного первого полета гиперзвукового аппарата Falcon HTV-2, состоявшегося 20 апреля 2010 года. Как сообщает Defense Aerospace, точных причин неудачных испытаний установить не удалось. Предположительно, сбой ракеты произошел из-за неправильной работы систем управления аппаратом.

Напомним, 20 апреля аппарат стартовал на борту ракеты-носителя Minotaur IV с базы ВВС США Ванденберг в Калифорнии. Согласно плану первого полета, Falcon должен был пролететь 4,1 тысячи морских миль (7,6 тысячи километров) за полчаса и упасть неподалеку от Атолла Кваджалейна. Предположительно, аппарат сумел развить скорость в 20 чисел Маха в верхних слоях атмосферы, однако в полете связь с ним была утеряна, из-за чего испытатели не могли получать телеметрическую информацию.

Наиболее вероятной причиной неудачного запуска DARPA считает недостаток системы управления полетом Falcon - неправильно установленный центр тяжести ракеты, а также недостаточная подвижность рулей высоты и стабилизаторов. Предположительно, в полете ракета стала поворачиваться вокруг продольной оси. При этом ограниченная система управления не позволила выровнять полет. Когда вращение достигло предельного значения, установленного в программе, ракета самоуничтожилась.

Следующий запуск Falcon HTV-2 запланирован на лето 2011 года. Программное обеспечение аппарата изменено не будет. При этом конструкция аппарата, согласно рекомендациям DARPA, будет незначительно изменена. В частности, инженеры несколько сместят центр тяжести ракеты, уменьшат угол атаки в полете, а также доработают элементы управления.

Falcon разрабатывается с 2003 года. Сейчас программа является частью концепции оперативного глобального высокоточного удара Пентагона. Эта концепция предполагает быстрое нанесение ударов в любой точке мира обычными видами вооружения. Не исключено, что FHTV, оснащенный обычной боеголовкой, будет использоваться вместо баллистических ракет, поскольку запуск последних может быть расценен другими странами, как ядерная угроза. ВВС США также рассматривают возможность применения аппаратов, подобных FHTV, в качестве систем разведки и наблюдения.


Falcon HTV-2. Изображение с сайта ifpafletcherconference.com

Оригинал статьи:
http://www.defense-aerospace.com/article-view/release/120057/darpa-concludes-review-of-falcon-htv_2-failure.html

[flateric]