Help with a Movie I'm looking for...

[sentiant]

I'm trying to find the name of a movie with a date range 1975 to maybe 1980. It was about a man who is an astronaut and who is somehow changed into a cyborg type human. He is normal until threatened and then his body sprouts metallic tubes, etc. and he is able to defend himself. When he is transformed into the cyborg he can withstand extreme heat, pressure, bullets, etc. and the cyborg suit also gives defense warnings internally. At the end of the movie it shows a space launch with him aboard going to mars or venus. I only caught the last 15 to 20 minutes of this movie when it was on way back then and have been wondering ever since. What really got me wondering about this movie was the special effects were awesome, comparable to what we have today.<br /><br />Any help would be appreciated.