The article ``NASA Aims for Mars `On the Cheap,' '' Feb. 16, contained errors that negate the author's main point.
The article begins by accurately describing the new Mars Surveyor program. This will be a series of small orbiters and landers launched to the red planet, beginning with the first orbiter in 1996. He also describes the Mars Environmental Survey (MESUR) program, which would place a network of stations on the planet's surface to take seismic measurements, establish weather stations, and so forth.
He calls this a ``billion-dollar Mars exploration scenario for the rest of the 1990s broken into two disparate pieces,'' and says that it ``smacks of sloppy planning.''
The problem with this statement is that there is in fact only one piece, not two. Mars Surveyor has not been added to MESUR in NASA's plans, it has replaced it. MESUR will not be flown, and no funds are requested for it; NASA is requesting funds from Congress to fly Mars Surveyor instead of MESUR.
There also appears to be some confusion over the goal of the Pathfinder mission, scheduled for launch in 1996. The purpose of Pathfinder is to develop the technology necessary to deliver a small, inexpensive lander to the Martian surface.
Pathfinder is every bit as applicable to the Mars Surveyor landers as it would have been to the MESUR landers. It will operate independently of the 1996 Mars Surveyor orbiter for a simple and prudent reason: risk avoidance. Either spacecraft may succeed if the other fails.
For many years, NASA's plans for Mars exploration called for Mars Observer followed by MESUR. Mars Observer failed, and MESUR was too costly. In making the change to Mars Surveyor, NASA has scaled back its ambitions in order to save the taxpayers' money. Mars Surveyor will cost far less than the Mars Observer/Mesur combination, both per year and in total.
It is scientifically exciting, fiscally responsible, and deserving of careful consideration from the Congress and the American public. Steven W. Squyres, Ithaca, N.Y. Chairman, Mars Science Working Group
Regarding the article ``Audubon's Magnificent Birds Migrate North to Boston,'' Feb. 15:
Especially since it is Black History Month, I am disappointed that the article did not mention that John James Audubon was from Santo Domingo [now Haiti] and his mother was [a Creole] of African descent. Joseph S. Vera, Cambridge, Mass.
Good motives for buybacks
The front-page article ``Gun Exchanges Gain Popularity in Major Cities, but May Not Reduce Violence,'' Jan. 27, seems to cast doubt on the effectiveness of the gun buyback programs.
These efforts have attracted support or are planned in at least 49 cities. They are often initiated by citizens; it is unfortunate that some people dismiss them as corporate ``grandstanding.''
Here in Boston, more than 500 citizens and 48 businesses contributed $70,000 to buy back 1,302 working guns last summer.
The businesses that gave money were not asked in most cases, they simply responded to a tangible method of ridding the streets of the weapons most responsible for the murder and mayhem that terrifies households and neighborhoods.
In the United States, about 53,000 guns have been retired by these methods. Ottawa and Toronto have retired another 31,000, along with 750,000 rounds of ammunition. The programs are popular largely because the government does not adequately control the proliferation of guns (one is manufactured every 20 seconds), nor does it regulate guns to make sure they are safe, as it does with automobiles.
Finally, the Brookings Institution in Washington has recommended a national gun buyback.
Unless we do something in the short term to get rid of these weapons, or at least control them, the murder rate is not going to subside.
Buybacks send a powerful message that guns are unsafe. The positive response to them from corporations and communities is just good business. Lewis S. Dabney, Boston