Technology Trends

Hand in the sky - A System for Removal of Large Orbital Debris

An effective orbital debris removal and relocation system is critically needed, given the large amount of debris, such as spent rocket bodies and dead satellites, in low Earth orbit (LEO). Presently, thousands of space debris objects are being tracked in order to allow planners to place new systems in an unobstructed orbit, or to help operators to manoeuvre space systems to avoid collision with space debris. Orbital debris poses disastrous interference and collision threats to neighbouring satellites, leading to actual collision incidents. The recent 2009 collision of the active Iridium 33 satellite was the first accidental hyper-velocity collision between two intact artificial satellites in LEO. 

At present, there are no proven means to relocate a satellite to a super synchronous burial orbit, or to deorbit it to burn in the Earth’s atmosphere. 

The Aerospace Corporation patented a satellite capture system called WALDO, which offers a possible solution via a “hand in the sky” device. WALDO was inspired by “WALDO 

& Magic, Inc,” a Robert Heinlein science fiction novel, in which the protagonist creates robotic hands, called Waldos, varying in size from microscopic to gigantic. The patented “satellite grabber” comprises a base satellite which, once in orbit, commands pneumatic deployment of long, slender, finger-like pods. The pods can be articulated by longitudinal tendon-like articulations, acting like a finger that curves around and captures the object. A combination of three such pods forms a “hand in the sky,” a Waldo, that captures the case, target objects are assumed to be passive and non-cooperative, as would be expected when collecting random dead satellites. The major advantage of WALDO is its ability to approach a target object from the front, embracing it all around with a controllable soft grab that would not damage appendages. 

WALDO was inspired by the Jet Propulsion Laboratory (JPL) Inflatable Antenna Experiment (IAE) of May 1996. The IAE was released from the shuttle and was deployed by inflation. The long sub-reflector pods and the main large space structure. These long slender pods, which extend far out in front of the sub-reflector to form a capture zone, are what inspired WALDO. In WALDO, the pods have articulation tendons running along the length of the spacecraft, enabling these sorts of large “fingers” to curve around and grab a space object. 

Concept of Operations 

A detailed end-to-end mission concept of operations (CONOPS) for WALDO has been developed. A one metric ton space object, located at 400-600 km, would be captured and then either moved to a suitable burial orbit or deorbited. The CONOPS includes: analysis and assessment of the propulsion system; deployable mechanisms and deployable inflatable articulating fingers; long-range and close-in navigation and control; real-time image processing and target attitude; precise autonomous motion control to achieve formation flying; docking to target; removal to desired orbit or deorbit; control satellite/spacecraft sizing; design, fabrication and test plans; and flight demonstration test plans. 

The CONOPS starts with a dead satellite, slowly rotating in a drifting orbit, which must be moved to a burial orbit. Ground tracking details of the target object are programmed into WALDO, along with detailed characteristics and images of the target satellite. WALDO plans the rendezvous trajectory using autonomous navigation, based on the NASA Advanced Video Guidance Sensor (AVGS) demonstrated in the Orbital Express Project. WALDO, which is also capable of close-in navigation, approaches the target using optical or imaging radar to establish orientation and motion of the object, and plans the final approach and capture. Navigating to a concentric rotation axis, WALDO establishes formation flying with the object, similar to the way in which the Space Shuttle and the Hubble tele-scope manoeuvre during repair missions. As soon as WALDO nears the object at a distance suited to deployment of the fingers, around one to ten meters, the grasping fingers are pneumatically deployed. The fingers are sized and arranged to surround the selected de-bris object; as an example, the fingers can be thirty meters long, oriented at about 120° angles. The target is then captured as the fingers embrace it in padded physical contact. When the de-bris is within reach, the motor mechanism pulls and tightens the tendon lines causing the fingers to wrap around the debris to secure the grasp. 

After capture, WALDO determines the removal trajectory to the disposal orbit, or the deorbit manoeuvre for the debris object, and fires its thrusters accordingly, performing either an insertion into outer super synchronous disposal orbit or a deorbit manoeuvre. 

Source: Space Safety, Spring 2012

Muscle Atrophy in Space 

The human body has adapted over millions of years to work and operate within the gravity field. The musculoskeletal system is sized to act, jump, grip, grasp, carry loads, move,maintain balance, and use and define all the motor control strategies which are necessary for a safe life on Earth. 

The absence of gravity makes working in a spacecraft physically undemanding. In a weightless environment, very little muscle contraction is needed to support the body and move around. Such effortless motion results in weakening of calf muscles, quadriceps and the muscles of the back and neck in a process called atrophy. An astronaut can experience a muscle mass loss as high as 5% a week. 

Even the heart is affected by atrophy. In space, blood pressure is about 100 mmHg throughout the body, with no differential between head and feet. When bodily fluids redistribute themselves in the new environment, astronauts ap-pear to have swollen faces and thin legs. The lack of blood pressure gradient means less blood is needed, causing the body to excrete about 22% of its blood volume. The heart doesn’t need to pump as hard to distribute the blood, there-fore it atrophies. 

If one could remain in space forever, muscle loss would not be a problem, but when crew members return to Earth their bodies have to readjust to gravity. Most space adaptations appear to be reversible, but the rebuilding process is not necessarily easy. While blood volume is typically re-stored within a few days, muscle recovery takes about a month. Bone loss is even more problematic, taking up to three years to recover. 

Zero-G Exercise 

The only way to minimize muscle atrophy in space is through intensive strength training exercise – up to 2.5 hours a day. But exercising in space is only effective if it entails some gravity-like resistive force. On ISS, this resistance is provided by strapping an astronaut to a treadmill with bungee cords. The straps are not particularly comfort-able, so astronauts can only exercise with loads of 60-70% of their body weight. Astronauts can include squats, dead lifts, heel lifts, and various presses and curls in their routines using the Advanced Resistive Exercise Device (aRED), which can provide more than 270kg of resistance. 

Even though these machines are partially effective in mitigating the effects of weightlessness on muscles, increasing loads on muscles and bones is not enough without taking care of fluid flows. 

Chibis aims to do just that. It is a Russian below-the-waist suit that applies suction to the lower body, simulating a gravity-like stress to the body’s cardiovascular system. In the days before returning home, cosmonauts perform a preparatory training in the suit consisting of drink-ing 150-200 millilitres of fluids, followed by a sequence of progressive regimes of negative pressure (from -15 to -30 mmHg) for five minutes each while shifting from foot to foot at 10-12 steps per minute. This protocol induces the body’s circulatory system to interpret the pressure differential be-tween upper and lower body as a gravity-like force pulling the blood (and other liquids) down. The exercise prevents much of the loss of cardiovascular function and of muscle, and may also be effective in reducing bone loss. 

Source: Space Safety, Spring 2012

'SPACE' in News

Launch of KSLV-1 (Korean Space Launch Vehicle-1) Delayed due to fuel leak

The KSLV-1 launch initially scheduled to take place at the Naro Space Center, South Korea on 26 October has been delayed after detecting a leak in the fueling system for the rocket's Russian first stage, according to media reports.  
It has been decided to remove the launch vehicle from the pad and to roll it back to the Assembly-and-Test Facility in order to fix the faults and to carry out additional check-outs. 

The 108 ft. tall KSLV 1 was being prepared for liftoff on Oct. 26 from the Naro Space Center, a facility about 300 miles south of Seoul.

"A leak has been detected from a connection between the first-stage rocket of the KSLV-1 and the launch pad," Korea's Science and Technology Minister Cho Yul-rei told Yonhap news agency. 

Cho said the leak had been detected a few hours before the launch time when helium was injected into the rocket to check its integrity. The launch will have to be delayed by at least three days, he added. Russian experts later confirmed a seal in the coupling device that connects the rocket to the launch pad had broken, Yonhap said.

The first two launch attempts were made in 2009 and 2010. Both of them failed. Development of the first South Korean rocket began 10 years ago.

Early next week, Russian and South Korean specialists will try to find out the cause of the damage to the sealer, the source said.

"The joint Russian-South Korean commission will definitively set the date for the launch early next week," he said.

"Obtaining the approval of the launch window from the International Civil Aviation Organization is a procedure that takes eight to 10 days," the source said.

The rocket is the country's first locally assembled space rocket with its first-stage thruster built by Russia's Khrunichev State Research and Production Space Center, and the rest of the rocket and its payload built by a South Korean team led by the Korea Aerospace Research institute (KARI).

The part-Russian, part-Korean KSLV is part of a $471 million rocket development program. South Korea builds the vehicle's solid-fueled second stage and payload fairing, while Russia provides the first stage under a contract signed in 2004.

SpaceX capsule, packed with supplies, set to return from station today (Oct. 28)

SpaceX's Dragon space capsule, currently on the first contracted mission to resupply the International Space Station, is scheduled to return to Earth on Oct. 28 afternoon.

At 12:20 p.m. PDT, the capsule is set to splash down in the Pacific Ocean about 250 miles west of Southern California.

It will be the culmination of the mission carried out by the Hawthorne company, which is officially known as Space Exploration Technologies Corp. The spacecraft delivered 882 pounds of cargo to the station earlier this month.

The mission is SpaceX’s first of 12 such cargo missions under a $1.6-billion contract with NASA.

The Dragon is set to return with 1,673 pounds of cargo and its departure from the space station was set to be webcast on NASA TV starting at 4 a.m. SpaceX's website will also carry a webcast of the mission.

The spacecraft will separate from the space station using the station's robotic arm and release at 6:25 a.m.

The craft is set make its way back to Earth by firing its Draco thrusters to de-orbit. Once the Dragon enters the atmosphere, it will deploy parachutes to slow its descent into the ocean.

There will be no live NASA TV coverage of Dragon's reentry and splashdown. Updates will be available on NASA and SpaceX Twitter accounts.

The craft is set to remain afloat until it's retrieved by ship.

If successful, it will mark the third time that SpaceX has launched a space capsule into orbit and had it survive a fiery reentry. The company previously pulled off the feat in test mission in May and December 2010.

Why astronauts experience low blood pressure after returning to Earth from space

New research in the FASEB Journal suggests that a major cause of low blood pressure during standing is the compromised ability of arteries and veins to constrict normally and return blood back to the heart Bethesda, MD—When astronauts return to Earth, their altitude isn't the only thing that drops—their blood pressure does too. This condition, known as orthostatic hypotension, occurs in up to half of those astronauts on short-term missions (two weeks or less) and in nearly all astronauts after long-term missions (four to six months). A new research report published online in The FASEB Journal (http://www.fasebj.org) solves the biological mystery of how this happens by showing that low gravity compromises the ability of arteries and veins to constrict normally, inhibiting the proper flow of blood. Prevention and treatment strategies developed for astronauts may also hold promise for elderly populations on Earth who experience orthostatic hypotension more than any other age group.

"The idea of space exploration has been tantalizing the imagination of humans since our early existence. As a scientist, I have had the opportunity to learn that there are many medical challenges associated with travel in a weightless environment, such as orthostatic hypotension, bone loss and the recently recognized visual impairment that occurs in astronauts," said Michael D. Delp, Ph.D., a researcher involved in the work from the Department of Applied Physiology and Kinesiology, and the Center for Exercise Science at the University of Florida in Gainesville, Florida. "Although I have come to realize that it is unlikely I will ever get to fulfill my childhood dream of flying in space, I take great satisfaction with helping in the discovery of how microgravity alters the human body and how we can minimize these effects, so humans can safely explore the bounds of our universe."

To make this discovery, Delp and colleagues examined arteries and veins from mice housed at Kennedy Space Center in Florida with blood vessels from groups of mice flown on three of the last five space shuttle missions—STS-131, STS-133 and STS-135. Mice flown on the STS-131 and STS-135 missions were tested immediately after returning to Earth, whereas mice from STS-133 were tested one, five and seven days after landing. Not only did they find that these mice experienced the equivalent of orthostatic hypotension in humans, they also discovered that it takes as many as four days in normal gravity before the condition is reversed.

"There has been considerable interest in sending humans to the moon, asteroids, and Mars," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal, "but what we're finding is that extended space missions have their own inherent risks above and beyond the obvious. If we ever hope to visit distant worlds for extended periods of time—or colonize them permanently—we've got to figure out how to mitigate the effects that low and no gravity has on the body. This report brings us an important step closer to doing just that."

CNES, ASI Favor Solid-Rocket Design For Ariane 6

CNES is evaluating these three launch vehicle concepts for a next-generation Ariane 6: two based on solid-rocket-motor technology plus an all-liquid-fueled launcher with optional solid-motor boosters.

If things had gone according to plan, Europe would be flying a more powerful and efficient version of its Ariane 5 rocket today, one that could compete in the commercial market without public subsidies, and development of a next-generation launcher would be well underway.

Instead, the Ariane 5 suffered a serious failure in 2002 that slowed plans to boost its performance and shelved what were mostly French ambitions to start work on a less costly successor.

An evolution of the Ariane 5 ECA that now delivers roughly half of the world's communication satellites to orbit each year, the enhanced Ariane 5 ECB would have entered service in 2006. But it was 2008 before the European Space Agency (ESA) approved low-level funding for early development. The project was rebranded the Ariane 5 Midlife Evolution (Ariane 5 ME), and the money—roughly €300 million—started to flow, most of it going to Ariane 5 prime contractor Astrium Space Transportation's facility in Bremen, Germany.

Aware of looming competition, French space agency CNES has been studying next-generation launch vehicle concepts for a modular Ariane 6 that would use existing technologies and production facilities to replace the cumbersome, costly and commercially reliant Ariane 5.

The timing, observers say, could be critical, as Europe has not faced such a momentous decision on a major launch vehicle development for nearly 25 years. During that time, France has been the primary financier of launch vehicle development in Europe. But for the first time in ESA's nearly 40-year history, the German government has formed a consensus in support of maintaining Europe's independent access to space and says it will contribute one-third of the cost to fund launchers, if ESA will approve €1.4 billion ($1.8 billion) for full-scale development of the Ariane 5ME.

Astrium says the money could yield an operational upgrade by 2017, freeing ESA member states from €120 million in annual price supports paid to Arianespace, the European launch consortium that manages commercial Ariane 5 missions. Such relief, however, would come more than a decade after the Ariane 5 ECB was slated to enter service, a piece of history not lost on the French, who are eager to start work on what they have tentatively dubbed Ariane 6.

To date, the CNES analysis favors the solid-rocket concepts. Bonnal says even in the worst-case scenarios that assume a 20% decline in market price after 2020, when the rocket would enter service, the solid-rocket configurations could survive on eight launches per year, including three institutional ones for government customers.

“Definitely, we prefer the solid configuration today,” Bonnal said Oct. 3, during the 63rd International Astronautical Congress (IAC) in Naples, Italy.

Bonnal says each design would be capable of delivering at least 2,100 kg (4,629 lb.) to geostationary transfer orbit (GTO), the destination of most commercial telecom satellites, and that two of them—one solid, one liquid—could haul more than 8,000 kg to GTO.

The three concepts have several features in common: a cryogenic upper stage 4.4 meters (14.4 ft.) in diameter with a common bulkhead architecture propelled by the Vinci engine that is in development under Ariane 5ME; a large fairing 5.2 meters in diameter; and a payload interface of 1,780 mm (70 in.) with the payload encapsulated.

One solid-motor configuration, the P1B, is based on a monolithic composite first stage with a 3.7-meter diameter powered by a P180 engine. A second stage would use a P110 engine topped with the cryogenic 31-ton upper stage and up to six optional P39 strap-on boosters.

Bonnal says launcher control would be achieved without thrust-vector control (TVC) for the strap-ons, but empennages are being considered to limit the dynamic nozzle deflection angle. “If we start having a thrust-vector control on all of the boosters, then in terms of cost, we're lost,” says Bonnal.

For the P1B, the first set of P39 boosters would be ignited at lift-off and then jettisoned, while the second set, depending on the configuration, could be ignited in flight and not jettisoned.

Similar to the P1B, the all-liquid H2C would use up to six strap-on boosters to carry as much as 8,400 kg to GTO. Twin main engines, capable of 150 tons of vacuum thrust derived from the Ariane 5 's Snecma-built Vulcain 2, would comprise the H165 first stage, which would be topped by a 31-ton cryogenic upper stage, he says.

A third design, the P7C, would use a single solid-rocket stage based on the P135 engine as a building block to be arranged in linear and “faggot” configurations. Like the P1B, the P7C would use a 3.7-meter-dia. monolithic casing. But, unlike the P1B, each of the P7C stages would feature TVC, a factor that could increase costs.

“You could have a configuration with three P135s making a real first stage, ignited all together on the ground and separated all together, so there is no need to have separations between the stages,” Bonnal says.

The P7C has the advantage of smaller stages, with the P135 falling in the range of what Europe 's mostly Italian-built Vega launcher demonstrated this year with its P80 first-stage engine, Bonnal says.

Indeed, Italy is eager for ESA to approve early work on such an Ariane 6 design, which could facilitate new development of a more powerful Vega engine that could lower production costs and greatly improve its competitiveness in the commercial smallsat market .

“For Vega, we want a P120 at a minimum,” says Enrico Saggese, head of Italian space agency ASI.

Saggese says moving to the more robust P135 could be a greater challenge, requiring a larger diameter for the stage , a new payload adapter and changes to existing tooling and production processes.

“But if we have a P135 for the Ariane 6 , this could be worked,” he said on the IAC sidelines. “We are pushing for a design decision in Caserta,” a Naples suburb where the November ministerial will take place.

Source: AWST, Oct. 15, 2012

Japan Pushes Replacement For H-IIA & H-IIB Launch Vehicles

It might be called an aerospace wrinkle in the problem of Japan's aging population: the impending retirement of a cohort of engineers who have experience in developing large space launchers. If the Japanese government does not act soon, these people will be playing leisurely rounds of golf while their successors struggle to relearn old lessons.

With that in mind, Mitsubishi Heavy Industries is urging the government to move immediately on developing a new family of space launchers. While other countries might shrug off the problem and just make do indefinitely with current equipment, Japan is in a less comfortable position, because its H-IIA and H-IIB rockets are notoriously expensive to launch. Moreover, those two launchers are caught in an economic trap: Their costs are so high, especially once yen are converted to dollars, that they can rarely be used commercially, so the production and launch infrastructure behind them cannot be worked fast enough to drive down those expenses.

Mitsubishi Heavy, which builds and operates the launchers mainly for the government, does have plans to improve the H-IIA, however, partly addressing limitations imposed by launches from Tanegashima, an island much farther from the equator than competing launch sites.

The Japan Aerospace Exploration Agency (JAXA) has previously outlined plans for the replacement launcher family, H-X, which would be based on the LE-X engine (AW&ST Aug. 8, 2011, p. 52). The agency has promoted the family's modularity as offering lower costs. These need to be halved, says the senior general manager of Mitsubishi Heavy's space systems business, Shoichiro Asada.

Japan needs to use the H-IIA and H-IIB four times a year to provide enough work for suppliers to be profitable, according to the company's calculations, although Mitsubishi Heavy itself can cope with a lower rate because it is a big business with the flexibility to move staff between divisions.

Asada also points to two further requirements for the new system. One would be shorter periods between booking and executing a launch. For the H-IIA, that is currently 1.5 years.

The second improvement would be to vibrate the payload less than other rockets do, easing design satellite requirements or improving reliability. Space launchers shake their payloads severely due to engine noise, aerodynamic effects and the impulse from the separation mechanisms. The H-IIA does that at least as much as its competitors, says Asada, adding that a new family would improve in all three areas.

More details can be had from AWST, Oct. 15, 2012

Technology Trends

 

Vibration data

Shock & Vibration Software & Tutorials

Aerospace engineers, particularly working  in 'shock & vibration' the above blog may be of use. Pl try ...

 

Canadian Space Agency unveils Rover fleet

On October 19, the Canadian Space Agency (CSA) introduced a fleet of rover prototypes intended for exploration missions on the Moon or Mars.

“Canada’s reputation for excellence has been carved out through decades of innovation and technological advances such as the iconic Canadarm, Canadarm2 and Dextre,” said Minister of Industry Christian Paradis. “That legacy continues with the Next Generation Canadarm and these pioneer terrestrial rovers.”

The rovers stem from a 2009 project that committed $110 million over three years to advance robotics and space exploration technologies. NASA has already expressed interest in the rovers, which include small vehicles designed to work along side astronauts as well as large vehicles closer to the mini-Cooper sized Curiosity rover now on Mars. Some are so large that they could conceivably be used to transport astronauts. “In fact, we have an invitation right now from NASA to start working on advancing these technologies and taking them to flight for eventually a mission,” said CSA’s director-general of space exploration Gilles Leclerc. One of the prototypes has already ibeen spun off into an electric powered recreational vehicle by MacDonald, Dettwiler and Associated (MDA).

 The rovers aren’t quite ready to head for the nearest planet, though. “The horizon we’re looking at in terms of taking the technologies on these terrestrial prototypes and transferring them into a real space mission to the moon or Mars is about 2020,” said Leclerc.

<Artemis is light weight 230 kg prototype designed for lunar exploration that operate autonomously or telerobotically. Artemis’ four wheel system can spin on spot.

  







 Bombardier Recreational Products developed this SL-Commander all terrain vehicle based on its work on the Lunar Exploration Light Rover. The SL-Commander is fully automated, able to navigate with or without a driver.

 

Take a look at some more rovers below:

This 40 kg micro-rover is named Kapvik, Innu for          >

wolverine. Kapvik small stature allows it to squeeze into caves and crevices. It uses its robotic arm to raise its sensors for navigation and surveying.

 

This Robot Explorer, or Rex, is intended to take soil samples from Mars. The six wheeled 140 kg rover completed a joint field test with NASA in 2010.

  This Micro-Rover Platform with Tooling         >
Arm is designed for squeezing into tight spots. It can accompany an astronaut or deploy from a larger rover, using a tether to navigates slopes up to 65 degrees.

 See these and more rovers being tested in the CSA video