News From Space: ESA Sets Sights on Space Debris

space_debrisIt’s no secret that the orbital space lanes are clogged with debris. In fact, our upper atmosphere is so clogged with the remains of dead satellites, old rockets, and assorted space garbage, that initiatives are being planned to remedy the situation. The ESA, for example, has the Clean Space Initiative; and the e.DeOrbit mission that aims to send debris-hunting satellites into orbit to clean up the mess.

The aim of this mission is to clean up the important polar orbits between altitudes of 800 to 1,000 km (500 to 625 mil) that face the prospect of becoming unusable due to the increasing buildup of space debris. As part of the plan, the ESA is also investigating the possibility of using space harpoons to capture large items, such as derelict satellites and the upper stages of rockets.

https://i2.wp.com/images.gizmag.com/gallery_lrg/space-harpoon.jpgThis is just the latest in a series of possible plans to capture debris. In the past, the ESA has revealed that it was looking at capturing space debris in a net, securing it with clamping mechanisms, or grabbing hold of it using robotic arms. However, the latest possibility calls for using capturing debris with a tethered harpoon, which would pierce the debris with a high-energy impact before reeling it in.

Such an approach would not be practical for smaller debris, but is aimed at reeling in uncontrolled multitonne objects that threaten to fragment when colliding with other objects. These sorts of collisions result in debris clouds that would steadily increase in density due to the Kessler syndrome – a scenario in which the density of orbital debris is high enough that collisions generates more debris, increasing the likelihood of further collisions.

Airbus Defence and Space's preliminary design for a space harpoon system (Image: Airbus De...The ESA says the space harpoon concept has already undergone initial investigations by Airbus Defense and Space in Stevenage – two aerospace developers based in the UK. The preliminary design incorporates a penetrating tip, a crushable cartridge to help embed it in the target satellite structure, and barbs to keep it sticking in so the satellite can then be reeled in.

The initial tests involved shooting a prototype harpoon into a satellite-like material to assess its penetration, the strength of the harpoon and tether as the target is reeled in, and the potential for the target to fragment, which would result in more debris that could threaten the e.DeOrbit satellite. The ESA now plans to follow up these initial tests by building and testing a prototype version of the harpoon and its ejection system.

space_laserThe project will examine the harpoon impact, target piercing and the reeling in of objects using computer models and experiments, ultimately leading up to a full hardware demonstration. The space agency has put out the call for bidders to compete for the project contract, and hopes to be sending a working model into orbit by 2021 to conduct some much-needed housecleaning.

Naturally, there are other proposals being considered for debris-hunting. Between the ESA and NASA, there’s also the EPFL’s CleanSpace One debris hunter, and the Universities Space Research Association anti-collision laser concept. And while these remains still very much in the RandD phase, clearing the space lanes is likely to become a central issue once regular missions are mounted to Mars and the outer Solar System.

Sources: gizmag.com, esa.int

News from Space: The Canadarm2!

Astronaut Steve K. Robertson during STS-114
Astronaut Steve K. Robertson during STS-114

For decades, the Canadian Space Agency has been building the Shuttle Remote Manipulator System (SRMS) – also known as the Canadarm. Since 1981, aboard the shuttle STS-2 Columbia, this model of robotic arm has come standard on all NASA shuttles and was used as its main grasper. However, due to the progress made in the field of robotics over the past thirty years and the need for equipment to evolve to meet new challenges, the Canadarm was retired in 2011.

Luckily, the CSA is busy at work producing its successor, the Mobile Service System – aka. Canadarm2. The latest versions are in testing right now, and their main purpose, once deployed, will be to save satellites. Currently, an earlier version of this arm serves as the main grasper aboard the ISS, where it is used to move payloads around and guide objects to the docking port.

canadarm2However, the newest models – dubbed Next Generation Canadarm (NGC) – are somewhat different and come in two parts. First, there is the 15 meter arm that has six degrees of freedom, extreme flexibility, and handles grappling and heavy lifting. The second is a 2.58 meter arm that comes attached to the larger arm, is similarly free and flexible, and handles more intricate repair and replacement work.

This new model improves upon the old in several respects. In addition to being more intricate, mobile, and handle a wider array of tasks, it is also considerably lighter than than its predecessor. When not in use, it is also capable of telescoping down to 5 meters of cubic space, which is a huge upshot for transporting it aboard a shuttle craft. All of this is expected to come in handy once they start the lucrative business of protecting our many satellites.

canadarm2_missioncontrolIt’s no secret that there is abundance of space junk clogging the Earth’s upper atmosphere. This moving debris is a serious danger to both manned and unmanned missions and is only expected to get worse. Because of this, the ability to repair and retool satellites to keep them in operation longer is of prime importance to space agencies.

Naturally, every piece of equipment needs to undergo rigorous testing before its deployed into space. And the Canadarm2 is no exception, which is currently being put through countless simulations. This battery of tests allows operators to guide dummy satellites together for docking using the arms in both full manual and semi-autonomous mode.

canadarm2_chrishadfieldNo indication on when they will be ready for service, but it seems like a safe bet that any manned missions to Mars will likely feature a Canadarm2 or two. And as you can see, Chris Hadfield – another major Canadian contribution to space – is on hand to help out. Maybe he and the new arm can perform a duet together, provided it can handle a guitar!

And be sure to check out this video of the NGC Canadarm2 in action, courtesy of the Canadian Space Agency:


Source:
Wired.com