No, it is not at all possible to send the mangal yan without the help of computers because everything thats responsible for taking the mangal yan to the mars is controlled by computers. It just cannot be even thought of the mangal yan mission without the use of computers. Its just all composed of the computers. If u take out the computers, how is it going to be controlled, how is it going to send the information and above all how is it going to collect information. Its just not thinkable. Let me tell u that if u take out the computers, the things left will just be the mechanical parts of the vehicle going to mars. Its all just computer.