MacDonald, Dettwiler and Associates, the prime contractor, was awarded the $65-million contract five years ago.
National Defence describes Sapphire as the largest part of the Canadian surveillance system, intended to increase "space situational awareness."
Sapphire will be used to support Canadian and international operations, as well as bilateral commitments such as NORAD.
The metre-long satellite, weighing about 150 kilograms, will track man-made objects and space debris that could pose threats to other satellites.
With a life expectancy of at least five years, Sapphire will be placed in a polar synchronous orbit some 800 kilometres above Earth. The satellite will detect more objects with better accuracy than specialized radars or telescopes on the ground.
Sapphire is scheduled for launch on an Indian rocket. It was supposed to be launched earlier this year with NEOSSat, another Canadian satellite. But the launch was pushed back because work on an Indo-French satellite, the rocket's primary payload, was delayed.
Com Dev International of Cambridge, Ont., and two other companies, Terma A/S of Herlev, Denmark, and Surrey Satellite Technology of Surrey, England, were also on MacDonald, Dettwiler's contracting team.
Microsat Systems Canada Inc. won the $12-million contract to build NEOSSat, short for Near-Earth Object Surveillance Satellite.
The Canadian Space Agency says NEOSSat is the world's first space-based telescope dedicated to detecting and tracking asteroids and satellites. It will scan space near the sun to pinpoint asteroids that may someday pass near our planet.
Sapphire will also contribute to the United States Space Surveillance Network, which currently tracks more than 22,000 pieces of space debris larger than 10 centimetres. There are another estimated 100,000 pieces of debris between one and 10 centimetres in size.
Even the smallest objects have the potential to seriously damage or destroy a satellite, which could potentially lead to the loss of millions of dollars.
The U.S. space surveillance network keeps a catalogue of space objects that is used by about 20,000 users in more than 130 countries.