Canada's search for asteroids
To have a satellite near Earth is good for young astronomers armed with all kinds of telescopes, it's good for their learning. But if they see the dot in the sky that get bigger and bigger, and eventually transforms into a large roughly shaped asteroid, than it's the time to be a bit worried.
To make us less worried, Canada is building the world’s first space telescope designed to detect and track asteroids and satellites. The project is called NEOSSat which is short for Near Earth Object Surveillance Satellite. NEOSSat will search for objects that may be on the collision course with Earth and it will also track the bunch of satellites we launched in orbit around our planet.
The mission is worth 12 million dollars and all that money will be squeezed into a 65-kilograms suitcase. Canada has experience with building micro satellites and such a small object means that it can be sent in orbit on practically every spacecraft. The money came from Defence Research Development Canada(DRDC) and the Canadian Space Agency(CSA), and those two agencies expect to see NEOSSat in space in 2010.
NEOSSat will be used in HEOSS (High Earth Orbit Space Surveillance) and the NESS (Near Earth Space Surveillance) asteroid search program. (I loooove those names: NEOSSat in HEOSS and NESS. The next mission obviously should be named HESS, HOSE, and ESSO. And I'd like to know who can repeat those names without making a mistake.)
"We are on the cutting edge, building the world’s first space-based telescope designed to search for near-Earth asteroids," said Guy Bujold, President, Canadian Space Agency. NEOSSat is the first follow up mission to the groundbreaking MOST (Microvariability and Oscillation of STars) spacecraft, a 60-kilogram satellite designed to measure the age of stars in our galaxy.
NEOSSat also marks the first project using Canada’s Multi-Mission Microsatellite Bus. CSA's Space Technology branch launched the Multi-Mission Bus project to capitalize on technology developed for the MOST project by making it adaptable to future satellite missions.
Dr. Brad Wallace leads the science team at DRDC for HEOSS, which will use NEOSSat for traffic control of Earth’s high orbit satellites. Dr. Wallace says, "We have already done satellite tracking tests using MOST, so we know that a microsatellite can track satellites. The challenge now is to demonstrate that it can be done efficiently, reliably, and to the standards required to maximize the safety of the spacecraft that everyone uses daily, like weather and communication satellites."
The HEOSS project will demonstrate how a micro satellite could contribute to the Space Surveillance Network (SSN), a network of ground based telescopes and radars located around the world. Until the 1980s, Canada contributed to the SSN with two ground-based telescopes in eastern and western Canada. The fact that HEOSS will be a space-based capability on a micro satellite represents an exciting enhancement to the contribution and offers significant advantages to the SSN.
Ground-based sensors’ tracking opportunities are constrained by their geographic location and the day-night cycle. In Sun-synchronous orbit around our planet, NEOSSat will offer continuous tracking opportunities and the ability to track satellites in a wide variety of orbit locations.
Although NEOSSat’s 15-centimetre telescope is smaller than most amateur astronomers’, its location approximately 700 kilometres above Earth’s atmosphere will give it a huge advantage in searching the blackness of space for faint signs of moving asteroids. Twisting and turning hundreds of times each day, orbiting from pole to pole every 50 minutes, and generating power from the Sun, NEOSSat will send dozens of images to the ground each time it passes over Canada. Due to the ultra-low sky background provided by the vacuum of space, NEOSSat will be able to detect asteroids delivering as few as 50 photons of light in a 100-second exposure. ■