Monday, July 14, 2014

Cygnus Spacecraft a Final Test for New Canadian Space Eyes

          by Brian Orlotti

An Orbital Sciences Corporation (OSC) Cygnus spacecraft, launched yesterday on a resupply mission to the International Space Station (ISS), will demonstrate Canadian technology that will make future spacecraft more capable.

The Cygnus spacecraft (dubbed the SS Janice Voss in honour of deceased NASA astronaut Janice E. Voss) was launched from the NASA Wallops Flight Facility in Virginia on Sunday, July 13th at 12:52 p.m. ET. The craft is scheduled to arrive at the ISS on July 15th, to deliver 1,360 kilograms of food, supplies, and experiments.

The Cygnus spacecraft. Photo c/o Wikipedia.
As it approaches the ISS, the Janice Voss will test the Triangulation and LIDAR Automated Rendezvous and Docking (TriDAR) system. The spacecraft will use the TriDAR to guide it to a point about 12 metres away from the station (called the "berthing box"), where it will hold and wait for the Canadarm2 to grab it and pull it into a docking port.

Although the TriDAR system is capable of guiding the spacecraft to the docking port on its own, NASA (presumably for safety reasons) won't permit it. On this mission, the TriDAR is serving as a backup to the Janice Voss' main guidance system, but for all following missions, the Cygnus vehicles will carry two TriDAR units each (a primary and a backup) and will fully rely on them to dock at the ISS. OSC will fly seven more resupply missions to the ISS as per its contract with NASA.

TriDAR was developed by Ottawa based Neptec Design Group Ltd. with funding from the Canadian Space Agency (CSA) and NASA and was previously tested on three space shuttle missions (STS-128131 & 135). The system uses both an infrared camera and LIDAR (aka laser radar) to create a 3D model of objects it detects in space (in this case, the ISS). The TriDAR then compares the model of the detected object to one of the ISS stored in its memory. Using this data, the TriDAR can change the spacecraft's orientation and enable it to dock.

Traditional automated space docking systems guide spacecraft by using video cameras to hunt for a "target," a specific pattern painted or placed on the side of an object. The ISS, for example, uses a group of black-and-white polka dots. Although effective, this system has disadvantages. Should the target become obscured or damaged, docking can be hampered. The TriDAR system gives spacecraft greater flexibility. Beyond docking, Neptec forsees TriDAR being used in other areas, such as orbital space junk removal.

Brian Orlotti.
With LIDAR technology, spacecraft will become safer, more flexible and more capable. And Canadians are crafting the eyes that will guide them into the future.

Brian Orlotti is a Toronto-based IT professional and a regular contributor to the Commercial Space blog.

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