When Dr. Kathryn Sullivan, the shuttle astronaut, floated out of Challenger's cargo bay last week and became the first American woman to walk in space, it was a historic moment in two decades of manned space excursions.
At about the same time, the release by the American Association for the Advancement of Science of its 1984 Scientific Manpower Commission study of professional women and minorities focused renewed attention on the changing status of women scientists here on Earth.
These events give two more indications that science in America is indeed evolving, that it is no longer the male preserve it was in 1960s. Already the growing number of women within the scientific and engineering disciplines is sparking speculation about their possible effect on science policy. Most observers, however, remain less than sanguine about the hurdles women continue to face in science careers.
According to the latest Scientific Manpower Commission figures, women have made significant educational gains in the science fields over the last 20 years. Between 1965 and 1983 the share of US science and engineering doctorates awarded to women grew from 7 percent to 26 percent. At the bachelor's level the proportion grew from 22 percent to 36 percent.
''The biggest change is the continued increase in the numbers of women preparing for science careers,'' says Betty Vettor, executive director of the commission. But she adds, ''Women are given far less opportunity for advancement (later on).''
For women working in science professions, the prospects may indeed be less encouraging than the educational statistics would indicate. Although observers say that little overt discrimination remains and that, indeed, ''the entire complexion of science has changed,'' statistics show that women remain in the minority in nearly every science field, and their ratios in the work force fall below their proportions in recent graduating classes.
''While increasing numbers of women are obtaining degrees in the quantitative fields, these same women remain underrepresented in the science and engineering labor force,'' says Sue Berryman, an analyst with the Rand Corporation and author of a recent Rockefeller Foundation study on women in the scientific work force. While some of this discrepancy is attributable to the slow growth of the professional labor force as a whole, other factors bear directly on the sciences.
Currently more than half of all college teachers in English, foreign languages, health specialties, and home economics are women, but in engineering and physics departments women constitute less than 5 percent of the faculty. And , on average, the higher-paying companies are still hiring men more than women; the Manpower Commission's survey of women's starting salaries within particular disciplines, such as biology and the social sciences, show that men may earn as much as $4,000 more than women employed elsewhere in comparable jobs.
In addition, the unemployment rates for women with science or engineering doctorates are two to five times as high as the comparative rates for men. According to Ms. Berryman, one-quarter of all women with advanced degrees in the quantitative fields are not employed in scientific and engineering jobs. And, among those women, the reason most often cited for nonemployment in the scientific labor force is family responsibilities. ''The whole (question) is one of women's preferences,'' says Berryman, ''but where do they get those preferences?''
According to her and other observers, women intent on a science career face several unique obstacles. Not only do salary discrepancies, tenure difficulties, and inadequate female role models and female colleagues hinder women's professional progress later on, but many women find their options limited early on.
''At the beginning of ninth grade a lot of girls are opting out of elective math,'' says Berryman. ''By the end of high school, boys and girls demonstrate differing levels of math ability. And unless you have the full mathematical sequence, the ball game is almost entirely over.''
''A great percentage of women and minorities are excluded from science even before they've begun,'' says Dr. Margaret Kivelson, chairwoman of the Department of Earth and Space Sciences at the University of California at Los Angeles.
Other observers point to the economic woes of universities during the 1970s as adversely affecting women's opportunities for professional advancement. ''The cutback in science funding, particularly at the big research universities, came right when there was the big push to increase the numbers of women faculty members,'' says Dr. Vera Kistiakowsky, a physicist at the Massachusetts Institute of Technology. ''As a result, faculties have gotten older and older, with few younger women members.''
While most observers insist that women's professional opportunities in academia should improve as the current crop of science faculty begins to retire during the next decade, others, including Dr. Kistiakowsky, insist that the ''mystique'' and exceptionally rigorous demands of a science career continue to affect women more than men.
Not only do the pressures to obtain research contracts, funding, and a reputation come early in a science career, but many women find such pressures work against raising children. Traditionally many married women scientists have stepped off the high-powered career path and into less competitive research-associate positions.
''In order to be competitive, (women) can't expect special consideration,'' says Dr. Cynthia Friend, an assistant professor at Harvard's Chemistry Department and the mother of two young children. ''People want to see what kind of science you do. You must be a scientist first and not let gender come into play.''
But it is precisely that question of gender that many observers within the scientific community are beginning to raise. A recent article in New Scientist magazine by Dr. Hedvah Shuchman, formerly of the New Jersey Institute of Technology, posed this question: ''When women rise to positions of authority in engineering, management, and scientific laboratories, will they shift the focus of government and industry from defense to health and welfare?''
Evidence for such a prospect is hard to come by. Not only do women remain in the minority in most scientific fields, but few statistics exist to support the hypothesis. While some observers say that administrative and leadership styles would more likely be affected than research-and-development decisions, others disagree. ''In some fields, such as medicine and biology, (increasing numbers of women) will make an enormous difference,'' says Dr. Kistiakowsky. ''But in those fields more detatched from everyday concerns, there will be virtually none.''
''The presence of more women at all levels will have a measurable effect on the kinds of science we do,'' says Dr. John Slaughter, chancellor of the University of Maryland and former head of the National Science Foundation.
Still others insist that federal funding decisions are most crucial to women's success in science. ''If more women controlled the grant mechanisms, there would likely be a difference in the proposals funded and in the projects proposed,'' says Betty Vettor.
Already the National Science Foundation has earmarked $2.5 million out of a $ 1.5 billion budget for 1985 for research projects specifically proposed by women entering and returning to science careers.