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Raumfahrt - Stratolaunch conducts high-speed taxi tests on giant carrier aircraft

27.02.2018

Last weekend, Stratolaunch Systems performed high-speed taxi tests of the world’s largest aircraft by wingspan. The tests represent continued progress towards the maiden flight of the plane. The Stratolaunch carrier aircraft will serve as a mobile launch platform for rockets including Orbital ATK’s Pegasus XL.

 

Stratolaunch was founded in 2011 by Microsoft co-founder Paul G. Allen, with the goal of increasing access to Low Earth Orbit. The system uses an aircraft to launch rockets instead of the traditional launch pad.

Air-launch comes with a few key advantages. For example, the launch vehicle has to fly through significantly less atmosphere. Also, weather delays are not as common, as the rocket is released from an altitude above most weather systems.

Initially, Stratolaunch planned to work with SpaceX to develop a launch vehicle. The goal was to build a four or five engine variant of the Falcon rocket designed for air-launch. However, work between the companies ended in 2012, after SpaceX determined that too many modifications were required.

As a result, Orbital Sciences (now Orbital ATK) was selected to replace SpaceX. Unlike SpaceX, Orbital already had a proven air-launch vehicle in the Pegasus – a rocket with 29 successful launches in a row.

Orbital ATK’s Stargazer carrier aircraft releases a Pegasus XL rocket carrying NASA’s Cyclone Global Navigation Satellite System. Image by NASA.

While Orbital ATK prepares to begin operations with Stratolaunch, the fate is unclear for launches from Orbital’s Stargazeraircraft – the current carrier for Pegasus. There is only one Stargazer based launch remaining on the Pegasus manifest – the Ionospheric Connection Explorer (ICON) mission for NASA. Therefore, it is possible that all Pegasus missions will transition to Stratolaunch after ICON launches in 2018.

Stratolaunch will carry the Pegasus from a carbon fiber aircraft designed by Scaled Composites – the same company that built WhiteKnightTwo (WK2) for Virgin Galactic. Like WK2, the Stratolaunch plane features a dual fuselage design.

While both fuselages on the carrier have windows, the three-person crew will fly in the right fuselage. The left fuselage is not human rated and thus will only house electronics.

The plane is propelled by six jet engines which have been salvaged from two 747s. Additional components from the 747s were also utilized, including landing gear, windows, avionics, and actuators.

The Stratolaunch aircraft features three 747 jet engines on each side. Photo by Stratolaunch.

The wingspan of the carrier aircraft is a world record breaking 385 feet (117 meters) – long enough for the Wright brothers to complete their historic flight three times. Additionally, it also makes the carrier wider than the Saturn V rocket is tall.

In addition to the massive wingspan, Stratolaunch has a carrying capacity of 549,290 pounds (249,153 kilograms) and a 1,000 nautical mile mission radius. These metrics will enable up to three Pegasus rockets to be launched in a single flight. They also create the potential for larger launch vehicles to be launched from the aircraft, as the plane is not exclusively designed for Pegasus.

A Stratolaunch visualization of their aircraft carrying three Pegasus rockets.

In May 2017, the Stratolaunch plane rolled out of its hangar at the Mojave Air and Space Port for the first time to begin fuel tests.

In the fall, Stratolaunch moved into stationary engine tests. These were incremental, with the engine’s power gradually increasing over time.

 

Around the same period, Stratolaunch also announced that it had conducted “prerequisite testing of the electrical, pneumatic, and fire detection systems.”

Finally, in December Stratolaunch capped off the year with a successful low-speed taxi test. During the taxi, the vehicle reached a top speed of 28 miles per hour (45 kilometers per hour) as it headed down the runway.

Following the test, Aircraft Program Manager George Brugg stated, “This was another exciting milestone for our team and the program. Our crew was able to demonstrate ground directional control with nose gear steering, and our brake systems were exercised successfully on the runway. Our first low-speed taxi test is a very important step toward first flight.”

Last weekend, Sratolaunch kicked off 2018 with two days of additional taxi tests. Most notably, the tests included reaching the maximum taxi speed of 40 knots  (46 miles per hour). According to Allen, these tests allowed the team to “verify control responses.”

After that, the path remains unclear. Stratolaunch likes to keep a low-profile in terms of scheduling. However, as of last year 2019 was the target for the first launch.

During commercial operations, the aircraft will be capable of performing approximately one mission per week. Stratolaunch will primarily fly out of its base at the Mojave Air and Space Port. However, other airports can be utilized, as long as they can handle the large wingspan.

Initially, Stratolaunch will carry one launch vehicle at a time. Flights with multiple rockets will occur once operations ramp up. Release will occur at approximately 35,000 feet (10,668 meters).

Quelle: NS

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Update: 1.03.2018

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Stratolaunch Lumbers on Toward First Flight

Recent taxi tests ramp up the speed of the world’s largest aircraft.

 

Mojave, California-based Stratolaunch Systems Corp has released a video showing good progress in the extensive taxi testing that precedes the upcoming first flight of the largest aircraft in the world by wingspan. The dual-fuselage, six-engine jet reached speeds up to 40 knots while cruising down Mojave Air and Space Port’s runway 30.

“The team verified control responses, building on the first taxi tests conducted in December,” said Stratolaunch’s founder Paul Allen in a tweet on Monday.

The runway is 12,503 feet long, providing plenty of space for the massive airplane to accelerate and decelerate during the testing. However, the wings of the Stratolaunch span way beyond the 200-foot wide runway. The Stratolaunch boasts a wingspan of 385 feet, nearly twice the width of the runway.

Quelle: FLYING

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Update: 7.03.2018

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Why is Paul Allen building the world’s largest airplane? Perhaps to launch a space shuttle called Black Ice.

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A massive airplane being built by Microsoft co-founder Paul Allen moved a step closer to flight last week, when it crept out of its hangar in Mojave, Calif., and practiced rolling down the runway, hitting a top speed of 46 mph.

Known as Stratolaunch, the plane has a wingspan even greater than that of business mogul Howard Hughes’s famed Spruce Goose and is designed to carry as many as three rockets, tethered to its belly, to about 35,000 feet. Once aloft, the rockets would drop, then fire their engines and deliver satellites to orbit.

But Allen has even bigger ambitions for Stratolaunch and is considering pairing it with a new space shuttle that’s known inside the company as Black Ice.

stratolaunch-aa-2

In exclusive interviews last summer, Allen and Jean Floyd, Stratolaunch System's chief executive, laid out the company’s plans for the giant plane, providing an answer to why anyone would want to build an aircraft that has 28 wheels, six 747 jet engines and a wingspan longer than a football field.

“I would love to see us have a full reusable system and have weekly, if not more often, airport-style, repeatable operations going,” Allen said in an interview in his Seattle office.

The Black Ice space plane — should it be built — would be about as big as the former space shuttle developed by NASA and capable of staying up for at least three days. It could be launched from virtually anywhere in the world, as long as the runway could accommodate Stratolaunch’s size. And it would be capable of flying to the International Space Station, taking satellites and experiments to orbit, and maybe one day even people — though there are no plans for that in the near-term.

Then it would land back on the runway, ready to fly again.

“You make your rocket a plane,” Floyd said. “So, you have an airplane carrying a plane that’s fully reusable. You don’t throw anything away ever. Only fuel.”

For now, the company is focused on the maiden flight of Stratolaunch, which could come later this year. Then it would decide whether to pursue Black Ice.

Returning to human spaceflight could be a possibility sometime in the future, said Allen, the billionaire entrepreneur, who founded Microsoft with Bill Gates and now owns the Portland Trail Blazers and Seattle Seahawks.

“If you caught the bug back in the Mercury era, of course it’s in the back of your mind,” he said. “But I think you’re seeing right now, other than [space station] resupply missions, most spaceflights are about launching satellites. That’s the reality. And they are extremely important for everything from television to data all over the world. You can get data in the Kalahari Desert because there’s a satellite up there.”

Stratolaunch has generated all sorts of interest, a curiosity that for years was being built in secret inside a hangar so big that the contractor fashioning it, Scaled Composites, needed special permits just for the construction scaffolding.

Vice President Pence has visited the plane in its hangar and walked across its wingspan. Air Force Secretary Heather Wilson has dropped by to see it as well, writing on Twitter that she had “the chance to see firsthand how Stratolaunch is developing an air-launch platform to make space more accessible.”

Allen made history in 2004, when he hired Scaled Composites to build another spacecraft called SpaceShipOne that won the Ansari X Prize when it became the first nongovernmental vehicle to reach the edge of space. Allen ultimately licensed the technology behind the spacecraft to Richard Branson, whose Virgin Galactic is now pursuing its own plan to fly tourists to space aboard yet another new space plane, known as SpaceShipTwo.

“Flying test pilots, I understand,” Allen said. “But paying-man-on-the-street-type passengers, I wanted to leave that to someone else.”

After bowing out of the space business, Allen eventually returned to pursue one of his greatest passions, and in 2011 announced that he was building Stratolaunch. “You have a certain number of dreams in your life you want to fulfill,” he said at the time. “And this is a dream that I’m very excited about.”

Allen, a connoisseur of antique planes, has amassed a collection of World War II relics that he had painstakingly refurbished. He recovered them from old battlefields — a Messerschmitt, a German fighter plane, was dug out of a sand dune on a French beach where it had been buried for decades; an Ilyushin IL-2M3 Shturmovik was pieced together from the wreckage of four planes recovered in northwest Russia.

To showcase his collection, Allen created a museum, the Flying Heritage & Combat Armor Museum in Everett, Wash., which features a Grumman F6F-5 Hellcat and a B-25 Bomber, among others.

As a child, Allen knew all the names of the Mercury 7 astronauts, as if they were the players of his favorite baseball team, and he wanted to be an astronaut when he grew up. But then in the sixth grade, he no longer could see the blackboard, even from his front-row seat. His nearsightedness meant “my dreams of being an astronaut were over,” he said. “Somehow I knew you had to have perfect eyesight to be a test pilot, and so that was it for my astronaut career.”

He once tried to launch the arm of an aluminum chair by packing it with powdered zinc and sulfur and firing it from a coffeepot, he recalled in his memoir, “Idea Man.” It didn’t work.

“Turns out the melting point of aluminum was lower than I understood,” he said.

As an adult, his passion for space continued. In 1981, he went to the Kennedy Space Center to watch the first shuttle launch. “The sound was unbelievable,” he recalled. “The air was vibrating, and you could feel compression waves going into your chest. … You could feel the heat from the engines on your face.” Allen watched it alongside the thousands who had packed the Florida coastline, many yelling: “Go! Go! Go!” “It was so inspiring,” he said.

In a post on Stratolaunch’s website, Allen said he has long been “enthralled by the idea of space exploration. … But I would have never imagined that, more than 50 years later, access to low Earth orbit would still be costly, complex and difficult. I am determined to change this to help maximize the potential of space to improve life here on Earth.”

A fully reusable shuttle would go a long way toward doing that, especially if it were capable of deploying constellations of small satellites. In the interview, Allen said he was keenly interested in that technology.

“The capabilities of these small satellites is something that’s really interesting and fascinating, both for communications, where a lot of people are putting up constellations of satellites for monitoring the challenged health of our planet,” he said. He’d become particularly interested in how space could be used to keeping an eye on “things like illegal fishing in the ocean, which is an increasing problem.”

Quelle: The Washington Post

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