Some people believe that the shuttle should have been better engineered for crew safety, including provisions for repair of the shuttle during the mission, escape of the crew when problems occur during launch, or having a backup shuttle ready to launch for rescue missions. What are some reasons why NASA would not have planned this when the shuttle was designed?

Some of the reasons why NASA would not have planned this when the shuttle was designed was that, they just wanted to launch it by any means and wanted to save cost of launching the space shuttle.

Secondly, the NASA were over confident  that the mission is designed well and is going to come out successfully.

Explanation:

Solution

It is mentioned that some people or individuals that the space shuttle was not  effectively designed and did not carry any provision for crew safety; it did not provide for repair of the shuttle while on a mission; it did not carried anyway round the crew to escape if problems occurs with the space shuttle; and lastly there was no availability of backup space for rescuing this mission.

Some of the reasons why NASA would have not have planned for thus kind of conditions while launching the mission is stated as follows:

The NASA just wanted to launch by any means and also did not want to increase cost of launching this space shuttle by having a back up for the same purpose.

It could also be that the NASA was very confident  and self sufficient that the mission is designed well and is going to be a success. this could be one of the major reasons the NASA did not pay attention towards making provision for the space shuttle mission and it was also a lack of responsibility from the NASA's side that it became over confident and pay no attention towards the safety of the crew going on the mission.