I cannot agree with Theodore R. Simpson's assertion {letter, Oct. 17} that because most of the 40,000 children who die each day from malnutrition and disease live outside the United States they ''are not our direct concern.'' The underlying conditions of poverty and deprivation that cause those deaths also cause damage to the environment, overpopulation and social unrest, which ultimately are everyone's concern.

Nor, however, can I see any logic in Jessica Mathew's overworked argument that the money to solve the world's problems should come from NASA's budget {"The Mars Extravaganza," op-ed, Oct. 5}.

The fact is that the United States spent about $13.7 billion this year in various forms of foreign aid, and less than half of that money went to development assistance programs (some, but not all of which, are intended to help the poor and hungry). The rest of our foreign aid went for military strife in the developing world. If we want more money to go to primary health care and education in the recipient countries, it makes better sense to take the money from other parts of the foreign-aid budget than to scrap our space exploration program.

There's no need to alienate well-intentioned supporters of space exploration in the name of the world's poor. We can go to Mars and support meaningful development in Bangladesh too.

MICHAEL H. HOLMES Gaithersburg