The reusable, unmanned craft is designed to operate in Earth orbit for extended periods; its prior missions in 2010 and 2011 lasted 224 and 469 days.

The US government has been resolutely quiet about its precise purpose, and would not confirm a launch time.

That has prompted fevered speculation as to the craft's ultimate purpose.

Tuesday's launch had been pushed back from October, delayed by two satellite launches. Patrick Air Force Base in Florida gave notice of a hazard from a launch in a window between 15:45 and 22:15 GMT (10:45 to 17:15 local time).

The X-37B craft, designed by aerospace giant Boeing, shares more than just a passing similarity to the now-retired space shuttle.

It is just a quarter the size of the shuttle, but is launched on a rocket - the Atlas V. It is coated in thermal tiles to withstand the heat of re-entry, after which it lands on its own gear autonomously.

The stated mission of the craft, according to the US Air Force, is an "experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform".

But the latest mission in particular sparked speculation that the craft was spying on the Chinese space lab Tiangong-1 - an idea that has since been largely discredited.

If nothing else, it seems the team behind the X-37B is interested in pushing the limit of flight duration far beyond its 270-day specification.

When it returned from its second mission in June, programme manager Lt Col Tom McIntyre said: "We knew from post-flight assessments from the first mission that OTV-1 could have stayed in orbit longer. So one of the goals of this mission was to see how much farther we could push the on-orbit duration."

But any official mission objectives seems set once again to remain secret.

The UK company developing an engine for a new type of spaceplane says it has successfully demonstrated the power unit's enabling technology.

Reaction Engines Ltd (REL) of Culham, Oxfordshire, ran a series of tests on key elements of its Sabre propulsion system under the independent eye of the European Space Agency (Esa).

Esa's experts have confirmed that all the demonstration objectives were met.

REL claims the major technical obstacle to its ideas has now been removed.

"This is a big moment; it really is quite a big step forward in propulsion," said Alan Bond, the driving force behind the Sabre engine concept.

The company must now raise the £250m needed to complete the next phase of development.

This would essentially take the project to the final designs that could be handed to a manufacturer.

Although the British government has put significant sums into REL's technology in the past, the company's preference is to pursue city finance.

"The project to date has been more than 90% privately funded, and we intend to continue with that type of structure," explained Tim Hayter, the CEO of Reaction Engines Ltd.

"Yes, we would encourage government money but we're not reliant on it and we're certainly not depending on it.

"What is more important to us is government endorsement. That gives everyone the confidence that the UK is behind this project."

REL's idea is for an 84m-long vehicle called Skylon that would do the job of a big rocket but operate like an airliner, taking off and landing at a conventional runway.

The vehicle would burn a mixture of hydrogen and oxygen but in the low atmosphere the oxygen would be taken from the air, in the same way that a jet engine breathes air.

Only once it had achieved very high speeds would Skylon switch to full rocket mode, burning onboard fuel supplies.

Taking its oxygen from the air in the initial flight phase would mean Skylon could fly lighter from the outset with a higher thrust-to-weight ratio, enabling it to make a single leap to orbit, rather than using and dumping propellant stages on the ascent - as is the case with current expendable rockets.

If such a vehicle could be made to work, its reusability should transform the costs of accessing space.

But its success depends on the Sabre engine's ability to manage the very hot air entering its intakes at high speed.

These gases have to be cooled prior to being compressed and burnt with the onboard hydrogen.

REL's solution is a module containing arrays of extremely fine piping that can extract the heat and plunge the inrushing air to about -140C in just 1/100th of a second.

Ordinarily, the moisture in the air would be expected to freeze out rapidly, covering the piping in a blanket of frost and dislocating their operation.

But the company's engineers have also devised a means to control the frosting, permitting the Sabre engine to run in jet mode for as long as is needed before making the transition to full rocket mode to take the Skylon spaceplane into orbit.

It is the innovative helium cooling loop with its pre-cooler heat-exchanger that REL has been validating on an experimental rig.

"We completed the programme by getting down to -150C, running for 10 minutes," said Mr Bond. "We've demonstrated that the pre-cooler is behaving absolutely as predicted."

The UK Space Agency asked Esa's propulsion division to audit the tests, and the Paris-based organisation has declared its satisfaction with the outcome of the experimental programme.

"One of the major obstacles to developing air-breathing engines for launch vehicles is the development of the lightweight high-performance heat exchangers," it said in a statement.

"With this now successfully demonstrated by REL, there are currently no technical reasons why the Sabre engine programme cannot move forward into the next stage of development."

Dr Mark Ford, who heads the propulsion engineering group at the agency, added: "The gateway is now open to move beyond the jet age."

The next phase is a three-and-a-half-year project. It would see a smaller version of Sabre being built on a test rig. The demonstrator would not have the exact same configuration as the eventual engine but it would allow REL to prove Sabre's performance across its air-breathing and rocket modes.

"Its parts will be spread out slightly; there's no need for us to package it as we would a real engine," said Mr Bond.

"Also, we will want the ease of access to exchange parts, so it will look a little bit like an anatomy exhibition."

The UK government is currently assessing what its involvement should be in the next phase of Skylon/Sabre, but David Willetts, the science minister, was keen on Wednesday to add his personal support to the project: "The engine being developed by Reaction Engines is a potential game-changer in terms of space technology," he said.

"This successful testing validates the assessment made of the engine concept by the UK Space Agency back in 2010 and is yet another example of the UK's world class space industry. It would be a fantastic achievement if we could one day use this home-grown technology for our own commercial space launches."

Esa is certain to do more study work with REL. Although it is currently working on new versions of its Ariane rocket - a classic expendable vehicle - the agency also wants to keep an eye on future launcher technologies.

REL itself is considering other applications for its technology. These could include incorporating Sabre-like heat-exchangers into existing gas turbine jet engines to improve their fuel-burn efficiency; and also into desalination plants.

1. Pre-cooler
During flight air enters the pre-cooler. In 1/100th of a second a network of fine piping inside the pre-cooler drops the air's temperature by well over 100C. Very cold helium in the piping makes this possible.
2. Jet engine
Oxygen chilled in the pre-cooler by the helium is compressed and burnt with fuel to provide thrust. In the test run, a jet engine is used to draw air into the pre-cooler, so the technology can be demonstrated.
3. The silencer
The helium must be kept chilled. So, it is pumped through a nitrogen boiler. For the test, water is used to dampen the noise from the exhaust gases. Clouds of steam are produced as the water is vapourised.

CBarca wrote:"He gazed up at the enormous face. Forty years it had taken him to learn what kind of smile was hidden beneath the dark red card. O cruel, needless misunderstanding! O stubborn, self-willed exile from the loving breast! Two gin-scented tears trickled down the sides of his nose. But it was all right, everything was all right, the struggle was finished. He had won the victory over himself. He loved Redoranje."

Meet the SR-72


In 1976, U.S. Air Force SR-71 Blackbird crews flew from New York to London in less than two hours, reaching speeds exceeding Mach 3 and setting world records that have held up for nearly four decades.

But those world records may not stay unbroken for long.

That’s because today, at the birthplace of the Blackbird – Lockheed Martin’s Skunk Works® – engineers are developing a hypersonic aircraft that will go twice the speed of the SR-71. It’s called the SR-72.

Son of the Blackbird
The SR-71 was developed using 20th century technology. It was envisioned with slide rules and paper. It wasn’t managed by millions of lines of software code. And it wasn’t powered by computer chips. All that changes with the SR-72.

Envisioned as an unmanned aircraft, the SR-72 would fly at speeds up to Mach 6, or six times the speed of sound. At this speed, the aircraft would be so fast, an adversary would have no time to react or hide.

“Hypersonic aircraft, coupled with hypersonic missiles, could penetrate denied airspace and strike at nearly any location across a continent in less than an hour,” said Brad Leland, Lockheed Martin program manager, Hypersonics. “Speed is the next aviation advancement to counter emerging threats in the next several decades. The technology would be a game-changer in theater, similar to how stealth is changing the battlespace today.”

A hypersonic plane does not have to be an expensive, distant possibility. In fact, an SR-72 could be operational by 2030. For the past several years, Lockheed Martin Skunk Works® has been working with Aerojet Rocketdyne to develop a method to integrate an off-the-shelf turbine with a supersonic combustion ramjet air breathing jet engine to power the aircraft from standstill to Mach 6. The result is the SR-72 that Aviation Week has dubbed “son of Blackbird,” and integrated engine and airframe that is optimized at the system level for high performance and affordability.


Hypersonic Research and Development

SR-72 is not the first hypersonic Skunk Works® aircraft. In partnership with the Defense Advanced Research Projects Agency, engineers developed the rocket-launched Falcon Hypersonic Technology Vehicle 2 (HTV-2). The HTV-2 research and development project was designed to collect data on three technical challenges of hypersonic flight: aerodynamics; aerothermal effects; and guidance, navigation and control.

The SR-72’s design incorporates lessons learned from the HTV-2, which flew to a top speed of Mach 20, or 13,000 mph, with a surface temperature of 3500°F.

A hypersonic aircraft will be a game changer.

Lockheed Martin Refines Hybrid Wing-Body Airlifter Concept
By Graham Warwick
Source: Aviation Week & Space Technology

Traditionally, performance drives military-aircraft design decisions and the energy implications of those choices are secondary. But as fuel costs eat into reduced budgets, the balance is shifting. Energy is fast becoming a critical constraint on operations, and the results could reshape aircraft design.

For now, the U.S. Air Force's efforts to cut fuel bills are focused on its transport and tanker fleet, which consumes two-thirds of the aviation fuel the service burns each year. While near-term retrofits—such as formation flying, winglets and other drag-reduction devices—can reduce the fuel consumption of existing aircraft, they will not provide the scale of savings sought in the long term.

The name of the Air Force Research Laboratory's (AFRL) Revolutionary Configurations for Energy Efficiency (RCEE) program says it all: Dramatic changes in aircraft design may be required to achieve significant reductions in fuel consumption.

The goal of RCEE Phase 1, which ran from 2009-11, was to define a next-generation mobility fleet that would use 90% less fuel than today's transports and tankers. Under Phase 2, which began in 2011 and will run until 2015, companies are taking a closer look at specific configurations.

In Phase 1, Boeing defined a mixed fleet that met the 90% savings target: an all-electric truss-braced-wing design with 20-metric-ton payload; a 40-ton-payload distributed-thrust hybrid-electric design; and a 100-ton payload hybrid-electric blended wing-body (BWB). In Phase 2, the company is taking a closer look at the distributed-thrust, hybrid-propulsion design.

Lockheed Martin, meanwhile, studied a wide range of configurations and technologies in Phase 1 in search of the 90% goal, concluding a hybrid wing-body (HWB) offers the most potential. In Phase 2, the company is further refining the concept, which combines a blended wing and forebody for aerodynamic and structural efficiency with a conventional aft fuselage and tail for compatibility with current airlift missions, including airdrop.

The twin-engine HWB is designed to take off in less than 6,500 ft. and fly 3,200 nm carrying 220,000 lb. of payload, including all the outsize cargo now airlifted by the Lockheed C-5. Lockheed calculates the aircraft will burn 70% less fuel than the Boeing C-17 through a combination of better aerodynamics, newer engines and lighter structures. “We use mature technologies to be affordable and could build it today,” says Rick Hooker, an aeronautical engineer at Lockheed Martin Aeronautics.

The HWB study is marked by a high degree of aerodynamic optimization using computational fluid dynamics (CFD) tools not available when today's airlift fleet of C-17s and Lockheed C-130s and C-5s was designed. Starting with a cruise Mach number of 0.7 as originally lofted, extensive shape optimization using CFD increased cruise speed to Mach 0.81 and reduced transonic drag by 45%, says Lockheed aeronautical engineer Andrew Wick.

Lockheed estimates the aircraft is 65% more aerodynamically efficient than the C-17, which is penalized by its 1980s design and the requirement for short-takeoff-and-landing (STOL) capability. The HWB is 30% more efficient than a C-5, and Lockheed says it is even able to achieve an aerodynamic efficiency 5% better than the Boeing 787, albeit at a lower Mach number.

That efficiency comes from several sources. To start, the blended forward fuselage carries 25% of the lift and moves the wing roots outboard, extending span and reducing drag without increasing wing weight. The spanwise lift distribution is improved and wing aspect ratio increased to 12 for the weight of a conventional aspect-ratio 9 wing,

The aft fuselage, meanwhile, ensures the aircraft is compatible with current loading and airdrop operations—a challenge for pure flying-wing designs like the BWB, says Hooker. The conventional T tail incurs a 5% drag penalty relative to a pure BWB, but provides robust control and avoids the cost and risk of developing new control effectors and algorithms for a flying wing to enable STOL and manage the abrupt center-of-gravity (CG) shift when airdropping heavy loads.

The aft fuselage is designed to provide a smooth flow field around the aft paratroop doors and cargo ramp, similar to a C-5, says Hooker. The tail is sized to handle a CG range of 20% mean aerodynamic chord, the same as a C-5. And the aircraft is designed so the tail is not needed for trim in the cruise, avoiding a drag penalty.

An unusual aspect of the HWB design is that the blended forebody encloses a circular pressurized fuselage. Some cargo is carried in unpressurized outer bays—pallets are loaded via the rear ramp, moved forward on floor rollers, then sideways through fuselage doors and into the outer bays on ball mats. The result is a pressurized fuselage that is smaller and lighter than the C-5's despite the similar cargo capacity. Lockheed calculates the HWB's structure is 18% lighter than a conventional design.

Another unconventional element of the configuration is the engine location above the wing trailing edge. Over-wing nacelles have long been avoided in aircraft design because of adverse transonic interference with the wing, but careful optimization by Honda of the engine location on the HondaJet has given the configuration new credibility.

Lockheed studied cruise interference drag with engines mounted in several locations—under and over the wing leading edge, over the trailing edge and on the aft fuselage—and generated more than 15,000 Navier-Stokes CFD solutions. The results showed that mounting the nacelles over the inboard trailing edge improved lift-to-drag ratio, regardless of engine type, for an aerodynamic benefit of up to 5% over a conventional under-wing location.

Three potential powerplants have been identified. General Electric's GEnx is available today, providing a 25% reduction in specific fuel consumption (sfc) over the C-17 and C-5M engines. Rolls-Royce's conceptual Ultra Fan has a 30% lower sfc and could be available by 2030. Third is a GE open rotor that could be available after 2025 with a 35% lower sfc. Combined with the improved aerodynamic efficiency and lighter weight, lower sfc results in the HWB burning 70% less fuel than a C-17 with GEnx engines, 75% with Ultra Fans and 80% with open rotors, Lockheed calculates.

Interestingly, despite diameters ranging from the GEnx's 11.8 ft. to an open rotor's 21 ft., “the wing optimized out to the same shape for all three engines,” says Wick. “The same wing for all three allows the engine installation to be modular. We could build it today and it would be designed to be able to be reengined.”

Analysis showed the over-wing installation offers other benefits, he says. The long wing chord ahead of the nacelle acts as a flow straightener to reduce inlet distortion and also shields fan noise from the ground. The overhang from the trailing edge means the engine is still accessible for maintenance and removal. And a smaller tail is possible with over-wing engines, says Hooker.

There is a powered-lift benefit from placing the engine nacelles over the trailing edge of the wing. “The inlet flow provides a large amount of suction lift on the wing,” says Hooker. This has a similar effect to the high-pressure area generated by under-wing engines blowing over deflected flaps, as happens in the C-17, and allows the over-wing engines to achieve a similar 15% increase in maximum lift coefficient.

To provide STOL capability, excess fuel volume could be traded for flap blowing to create a circulation-control wing, as in the STOL airlifter concept developed by Lockheed for AFRL's Speed Agile program. Another possibility is deflecting thrust downward, using flaps aft of the engine, core flow vectoring with an F-35B-style swiveling nozzle, or rotating the engines when the flaps deploy, “so they go along for the ride,” Hooker says.

Although RCEE is just a study effort, the Air Force will have to begin work on its next strategic airlifter in the near future if the C-17 is to be retired as planned starting in 2033. Noting it took 21 years to field the C-17, Hooker says ,“We need to start today to avoid a future gap.”

Look At This Ridiculous Russian Supersonic Cargo Plane Concept
Just, why?
By Kelsey D. Atherton Posted 5 hours ago



PAK TA Concept On The Ground
Scrrenshot [Sic] by author, from Vimeo

A face only a Cylon could love

Never mind the fact that Russian-backed separatists in Ukraine are struggling to win a civil war--the Kremlin wants to wow the Future with a gigantic supersonic cargo plane. Named the PAK TA, the concept from Russia’s Military-Industrial Commission will be a supersonic transport than can deliver Russian troops and tanks at high speed across the globe. And, according to Russia’s state-owned network, RT, they want them ready for military service by 2024.

The concept is as ambitious as it is improbable. Inside, Russia wants it to fit at least seven future tanks (also still in development), and then carry them through the sky at supersonic speeds of over 1200 mph to destinations up to 4000 miles away. That’s a speed unheard of for transports, and surpassed only by fighter jets. The F-22 Raptor, America’s fighter, maxes out at around 1500 mph. The C-5M Super Galaxy, America’s largest military transport plane, tops out at 518 mph. The PAK TA’s planned 200-ton capacity will enable it to carry one or two more tanks than the Super Galaxy, with the full planned fleet of 80 PAK TA’s capable of lifting at least 400 tanks to anywhere with a runway that can accommodate 80 gigantic cargo planes.

Making the PAK TA even more improbable is how it plans to fly: as a hybrid-electric airplane. Electric airplanes are rare today, and they often take the form of early concepts for luxury vehicles or NASA concepts. While improved batteries and electric engines mean all-electric airplanes are possible, it’s still unlikely we’ll see any military adopt a largely electric plane, much less a supersonic one, within the net decade.

All of this means the PAK TA is more likely a flight of fancy than a fancy flier. Watch a video of the plane below: [See official page via link below for video]

Soyuz Thruster Glitch Knocks Space Station Off-Kilter
Jun 10, 2015 06:05 PM ET // by AFP

The orbiting International Space Station has shifted in position after an engine glitch on a docked spacecraft which is due to bring astronauts back to Earth this week, Russia said.


The engines of the Soyuz spacecraft "switched on unscheduled which led to an insignificant change in the position of the ISS", Russia's space agency, Roscosmos, said in a statement on its website.

The Soyuz is docked at the ISS in readiness to take three astronauts home on Thursday, and Russia said "the necessary measures had been taken to stabilise" the space station and the glitch would not affect the astronauts' return.

"There is no threat to the crew of the ISS, the station itself or the return of the Soyuz TMA-15M ship to Earth on schedule," the space agency said.


The engines switched on for "less than a minute" during testing of the automatic docking system, a space industry source told the RIA Novosti state news agency.

Another source told the Interfax news agency that mission control probably gave the wrong command from Earth, meaning the Soyuz ship did not malfunction.

Russia's troubled space programme has experienced a series of recent failures. It was forced to delay the departure and landing of astronauts in May after a supply ship fell back to Earth after a rocket failure.


The space agency said the supply craft's design will be altered to prevent the problem occurring again with that particular type of rocket.

The next manned mission to the ISS is due to blast off between July 23 and 25, launching from Kazakhstan and carrying astronauts from Russia, Japan and the United States, Roscosmos said on Tuesday.