but Canada has far tighter immigration controls than the US
No it doesn't. If you work in certain fields, all you need to do is show up at the border with a letter of employment.
Only if you come from certain countries (possibly just the U.S.). If you come from one of the countries targeted by this H1B extension program (e.g. India), you most certainly need more than just a letter of employment. Not to mention that you won't be allowed on the plane without an entry visa.
Mangalyaan's six month mission is about collecting data that will be studied, reviewed, and scrutinized for far longer than the age of a "Gravity" blu-ray. It will continue to pay dividends long after its orbit has decayed. its actions pave the way for discoveries into planetary physics and science, not coffee mugs and concession sales. Mangalyaan's science may one day help solve some of the most complex questions in astrophysics, or it may help start colonies on other planets. Mangalyaan's goal is science, knowledge, and progress toward a bright future.
I think you are getting a little over-excited about the importance of Mangalyaan to "planetary physics and science". As the article correctly states, it's essentially a demonstration that "we can do it too" (from the Indian point of view). Its scientific value is fairly small given the number of Mars missions other countries have launched or will launch in the near future. It does help build local expertise in space engineering in India which one day may or may not make a significant contribution to mankind's efforts to solve complex scientific questions or colonize other planets.
P.S. It has nothing to do with astrophysics.
An authority is a person who can tell you more about something than you really care to know.