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Plenty of buzz going around about the mysterious stealth chopper left behind by U.S. Navy SEALs after they shot and killed Osama bin Laden last Monday morning, local time, in Pakistan.

Having suffered technical problems and a hard landing, the helo apparently couldn’t fly back out of bin Laden’s compound, and became evidence to be destroyed by the SEALs as they left in the other helicopter(s). The obvious aim was to keep the stricken helo from falling into the hands of the Pakistanis, and thereby, their allies the Chinese. So the SEALs blew it up, probably with grenades.

In the fireball began a firestorm of speculation among flight buffs about what exactly the aircraft was.

The consensus is that the helo was a stealthed-out version of the H-60 Black Hawk, made by Sikorsky. The tail boom, which survived the explosion and fire relatively intact, didn’t look much like anything the rest of us have seen. Case in point: a “hubcap” over the tail rotor, presumably to muffle the noise and hide it from radar, and angular lines reminiscent of stealth airplanes. According to an anonymous, retired special operations aviator interviewed by the Army Times, “Certain parts of the fuselage, the nose and the tail had these various almost like snap-on parts to them that gave it the very unique appearance.” The rotor also appears to have more blades than a typical rotor, which could reduce noise levels or allow it to operate at a lower rpm, also reducing noise.

The helicopter tail section, clearly stealthified. Photo: Reuters/Stringer

While the technology might be new, the idea of a “black” helo isn’t. Here’s a story about one in Vietnam.

More interesting, maybe, is that cell phone service and electricity in the vicinity of the compound went down just before the SEALs arrived, and came back up after they left, indicating that either the choppers or an aircraft loitering above employed advanced electronic countermeasures to further pull the wool over bin Laden’s eyes. It’s well known that electronic warfare airplanes such as the EA-18G Growler can jam wireless signals. But it is major news that they can jam electricity running through wires on the ground, if indeed that is what was happening.

Along with the Stealth Hawks, the new jamming abilities appear to be one more spoonful of secret potion now spilled to the world. And ain’t we just lappin’ it up?’

Photo: Ed Darack

Air & Space contributor in the field Ed Darack, who spent time on the ground and in the air in Afghanistan in the V-22 Osprey and other rotorcraft (here’s his story on the Osprey in Afghanistan), knows a thing or two about helicopters. He emails from Ft. Collins, Colorado that the Black Hawk is one of the most conspicuous and mass produced helicopters in the history of military aviation, and “has a number of variants that the general public does know about, including those for special operations purposes, although these are seldom photographed.”

Darack sends a few images below that show a U.S. Air Force Special Operations MH-60G Pave Hawk. “The ‘M’ designates ‘modified,’ ” says Darack, “typically for special operations purposes. I was lucky to get these shots at the end of the expeditionary airstrip at the Marine Corps Mountain Warfare Training Center near Bridgeport, California, preparing to photograph a Marine Corps CH-46 Sea Knight “Phrog,” when out of nowhere this Pave Hawk showed up during high altitude training to refuel.

Photo: Ed Darack

“The pilots didn’t seem to mind me photographing them and their aircraft,” he continues. “One of the distinguishing characteristics of the Pave Hawk is the refueling probe for extended duration flight. Was this model the progenitor to the ‘Stealth 60″ of the bin Laden raid? Maybe, but without a doubt, knowledge gleaned by pilots who fly these in training and actual combat went into crafting the mystery helicopter.”

Photo: Ed Darack

Late in 2014, a radically different type of rocket propulsion is set to show up on the International Space station for a period of experimentation.

The technology is called the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). It’s a rocket engine that uses electricity to ionize a gas such as argon, xenon, or hydrogen. Ionizing means that an electron gets knocked off of each atom in the gas, creating a plasma, which then gets energized in another section of the engine by radio wave antennas. This superheats the plasma until it is 200 times hotter than the surface of the sun. The plasma shoots out the back of the rocket through a system of magnets that align it properly to create highly efficient thrust. Read more about it here.

While not able to provide the explosive power of a chemical rocket for getting loads off the launch pad, VASIMR can create a steady stream of thrust for days or weeks and continually accelerate a spaceship away from Earth. It still looks plenty explosive in this 2009 max-power test:

The company that created it, Ad Astra, was founded by 7-time space shuttle astronaut Franklin Chang Díaz. He claims that VASIMR could get astronauts to Mars in 39 days instead of the six-to-nine months needed with chemical rockets. Ad Astra is located in Webster, Texas, not far from NASA’s Johnson Space Center. A VASIMR rocket on the ISS would have many uses, one of which would be to reboost the station to higher altitudes. With the looming retirement of the space shuttle, which used to handle that job, NASA likes the idea. Ad Astra claims that a VASIMR rocket could do this work for about 1/10th the current cost of $210 million a year. Other tasks that VASIMR could eventually handle include propulsion to enable satellite refueling, repair, and disposal, payload delivery to the moon, Earth departure stages for deep space probes, and various uses as a space tug for future vehicles in Earth orbit or beyond.

So how’s the VASIMR going to get up there? Chang Díaz writes to us that he never intended for it to actually go to the station on the shuttle. “I knew that program would soon end,” he says. “We always planned to go on one of the CRS [NASA's Commercial Resupply Services] vehicles, Falcon or Taurus II. We are still on that plan and do not have to down select the carrier until next year, so we are carefully watching the evolution of the CRS program.” When the engine finally gets there, it will be the culmination of literally decades of work.

Chang Díaz is excited about the outlook for VASIMR. In March he signed his fourth support agreement with NASA to collaborate on research, analysis and development tasks on space-based cryogenic magnetic operations and electric propulsion systems. In particular, the support agreement means that Ad Astra will provide NASA with an assessment of VASIMR’s high-power, low-thrust trajectories over a number of mission scenarios ranging from near Earth to deep space, while NASA will support Ad Astra’s efforts to mature the design of their 200-kilowatt VF-200 demonstration engine planned for the ISS, including use of specialized NASA facilities and equipment for the testing.

Chang Díaz emailed us from the country of his birth, Costa Rica, where Ad Astra has a second location, and said he was headed to Europe. “There is a strong current of interest in VASIMR developing in the old world as well, mainly Germany and Italy,” he says.

Here’s a neat video of a VASIMR payload delivery to the moon, which shows the advantages of the technology over traditional, chemical rockets.

You’ve heard of the UAV (unmanned air vehicle). Now check out the AUV (autonomous underwater vehicle): The REMUS 6000. It looks like a yellow torpedo. It’s a lot smarter. And it dives a lot deeper.

A REMUS 6000 closer to the surface. Credit: Brennan Phillips, Woods Hole Oceanographic Institution

Yesterday, the tenacious underwater ‘bot located at long last the remains of Air France flight 447, which plunged into the Atlantic Ocean on June 1, 2009.

The REMUS 6000 (Remote Environmental Monitoring UnitS) is the deepest diving AUV ever made, able to descend 6,000 meters, or almost 20,000 feet, below the ocean’s surface. It was developed jointly by the U.S. Naval Oceanographic Office, the Office of Naval Research, and the Woods Hole Oceanographic Institution.

Officials know only that the Airbus A330 wide-body jet encountered severe, high-altitude thunderstorms about three and a half hours into a flight from Rio de Janeiro to Paris, then fell from the sky. None of the 228 people onboard survived. Fifty-one bodies and some debris were found in the weeks following the accident, but search teams came up with precious little else, particularly answers.

What was clear was that the rest of the jet, including its black boxes (cockpit voice recorder and flight data recorder), and the remaining bodies, were somewhere deep in the fissures of the Mid-Atlantic Ridge more than two miles beneath the surface.

Left to right: Stephen Murphy, Mark Dennett, and Robin Littlefield of the REMUS 6000 Operations Group pose with one of the two AUVs owned by the Waitt Institute for Discovery. Both vehicles participated in the search for Air France 447. A third, owned by the Leibniz Institute for Marine Sciences in Germany, also participated. Credit: Tom Kleindinst, Woods Hole Oceanographic Institute

The REMUS 6000 was the ticket, able to cruise at up to four knots (4.6 mph) for up to 22 hours. Three vehicles equipped with an array of advanced sensors—including a high-resolution digital camera and side-scan sonar able to ping 2,000 feet out to both sides—combed the bottom in a lawn-mowing pattern. Launched and recovered from the vessel Alucia, which arrived on station March 25, the new effort marked the fourth attempt to locate the aircraft, and the second with the REMUS 6000. In a week, one of the AUVs found its quarry at 12,800 feet, about 2.5 miles down. They’ll narrow their search in the coming days for the black boxes.

Here are some photos of the airliner’s remains on the ocean floor at the web site of the French Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile, better known as the BEA. Together with Airbus and Air France, the BEA can now move forward with ideas for bringing pieces to the surface, and, perhaps, closure to the families.

Also, check out this video with scientists and engineers from the Waitt Institute for Discovery, which owns two REMUS 6000s, discussing a different project involving the AUV:

Crash test dummies aboard the Boeing 720, before the test. Credit: NASA

With ever-mounting budget cuts, and pressure to reduce the national deficit, NASA and the FAA just don’t crash airplanes intentionally like they used to. Here’s a golden oldie of a test the two agencies jointly conducted on December 1, 1984, when they took a Boeing 720 (a smaller, faster version of the 707) fully loaded with jet fuel and belly-flopped it onto the desert near Edwards Air Force Base in California. Engineers running the test, called the Controlled Impact Demonstration, were evaluating an anti-misting kerosene added to the standard Jet-A fuel, to see how the additive mitigated fuel ignition and flame propagation.

The test didn’t go quite as planned, as the remote control equipment used to direct the airplane brought it down off the centerline of the runway, with the left wing striking the ground first.

The researchers did get lots of useful data on features from test dummies to burn-resistant windows. But the fireball seen here, and the inferno that raged afterward, showed that a fuel additive wouldn’t make much difference in this kind of crash.

That’s one interesting question that a few former space shuttle astronauts and other experts were grappling with one day in early March at the National Research Council’s Keck building in downtown Washington, D.C. Around a large conference table sat NASA veterans Fred Gregory, history’s first black spacecraft commander, and Dick Covey, the pilot on the first shuttle mission after the Challenger disaster, along with former astronauts Dick Richards, Bonnie Dunbar, and Tom Jones, and several other subject experts. Called the Committee on Human Spaceflight Crew Operations, the dozen-plus members of the group are holding three meetings this winter and spring in Texas, Washington, and Massachusetts to study issues related to the shuttle’s retirement, such as the future activities of NASA’s Flight Crew Operations Directorate (FCOD), the requirements of crew-related ground facilities, and the size, nature, and mix of the astronaut corps’ fleet of training aircraft and whether that fleet will meet future training needs. The group had former space shuttle astronaut Ken Bowersox on a conference call from where he works at Space Exploration Technologies, or SpaceX, in Hawthorne, California.

Falcon 9 lifts off with the first Dragon capsule, December 8, 2010. Photo: SpaceX

Bowersox is SpaceX’s vice-president of astronaut safety and mission assurance, and is an advocate for the new commercial space opportunities being funded by NASA’s Commercial Crew Development program. “Sox,” as his old NASA colleagues call him (Covey was his commander on STS-61), said that the company’s Dragon spacecraft may operate in some modes as a “rental car,” where SpaceX would lease the vehicle to NASA, whose astronauts would then be in charge of the vehicle for trips to the International Space Station. The other possibility is that Dragon would operate in “taxi” mode, with a SpaceX astronaut taking NASA or international astronauts to and from the station.

But a larger discussion also looms about the extent to which a driver is necessary, as automation has become so advanced for launch, rendezvous, docking, reentry, and landing, that a pilot-astronaut on board actually takes up a seat that might be filled by some other qualified person, such as a scientist. (Attention Apollo astronauts and shuttle commanders: Please send no hate mail—we’re just the messenger.)

The Dragon spacecraft will carry seven people to the ISS. Image: SpaceX

It’s hard to imagine former space shuttle pilots agreeing to become basically passengers. But unmanned Russian Progress vehicles, European Automated Transfer Vehicles (ATVs), and Japanese H-II Transfer Vehicles (HTVs) dock unmanned at the ISS pretty frequently, the HTVs with the help of the station’s robotic arm.

For his part, Bowersox, who has flown four times as either a shuttle commander or pilot, and a fifth time as a shuttle passenger to the ISS, is open-minded to what the future may bring. A former U.S. Navy fighter pilot and test pilot, he admitted that the rental car mode is a bit more attractive to him than the taxi mode. But he did point out that many highly experienced cosmonauts, some of whom have commanded Soyuz capsules, have not come from Russia’s test pilot/fighter pilot culture, as all shuttle pilots and commanders have. Sergei Krikalev, with more time in space than any human being, was not even a jet pilot, but learned to fly in light aircraft. Alexander Kaleri, just returned from the ISS, has very limited aviation experience, according to Bowersox. Kaleri was the commander of Soyuz TMA-01M, which returned to Earth on March 16. And then there was Nikolai Budarin, another Soyuz commander. “Budarin was an anti-aircraft officer,” said Bowersox. “He was trained to shoot down pilots.”

ISS astronauts will berth Dragon to the station with the robotic arm. Image: Courtesy NASA

Automated spaceflight will take another step forward this summer with the next launch of SpaceX’s Dragon capsule, which, on its second trip to orbit, will rendezvous with the International Space Station. Bowersox told the group that SpaceX will halt the approach about 2.5 kilometers, or a couple miles, from the ISS. The third Dragon demo flight, planned before the end of 2011, will fly unmanned all the way to the station, where ISS astronauts will grapple the spacecraft with the station’s robotic arm and berth it to the station. If all goes well, Dragon will bring cargo to the ISS on 12 more unmanned flights before SpaceX would be ready for human spaceflight.