The following opinion was provided in a letter to the editor of a national aeronautics magazine:“Manned space flight is costly and dangerous. Moreover, the recent success of a series of unmanned space probes and satellites has demonstrated that a great

The author has cogently stated that we should invest our resources in unmanned space flight but he has failed to explain some important details and has made many assumptions that needs to be explained.

First and foremost, he has to explain the term "success". Is getting the pictures and information like if water exists or not, success? Or finding out that can life exists on outer space is success? If later is the success than manned spaced flight is the only solution to find that out.

Author has also assumed that the information gathered from unmanned space flights is enough while there are other very useful information like if the conditions are suitable for survival of living things and for that manned space flight is the only solution.

Author has failed to explain the terms "costly" and "dangerous". The statistics needs to provided that explains why is the manned space flight costly and dangerous? How many of pasts flights has resulted in casualties? Also he has not explained how successful are the unmanned space flights? Has there been significant tests that prove the success of unmanned flights or was it just one series of tests?

The other has also failed to realize the scenario where an unmanned space flight finds some thing which cannot be identified from pictures or something that exists inside some particular object. These things cannot be identified from unmanned flights but needs manned space flight.

This is premature of the author to conclude that we should invest more resources in unmanned space flights since technology can never completely replace a man.