Marija Strojnik, the astrophysicist who sees beyond the solar system

Ljubljana, 23 November - Marija Strojnik is one of the most accomplished living Slovenian scientists, her achievements including a method for autonomous navigation successfully used in the NASA Cassini mission to the outer planets. Extrasolar planet detection is Strojnik's main passion and a potential US return to the Moon could put her optics knowledge to excellent use.

Slovenian astrophysicist Marija Strojnik Scholl delivering the opening lecture at the Slovenian Festival of Science at the Faculty of Biotechnology earlier this year.
Photo: Bor Slana/STA

Strojnik, who has made a career in the US and Mexico, was born in Ljubljana in 1950 and already developed a passion for physics in primary school. Her father, Aleš Strojnik, was a brilliant engineer whose feats include the first electron microscope in Slovenia. He often let his inquisitive daughter keep him company and even assist him during his research work.

Early on, Marija showed a penchant for optics, which was also the topic of her secondary-school thesis and heralded the Ph.D. degree she would earn in 1979 at the College of Optical Sciences at the University of Arizona.

She had finished her undergraduate studies in only two years at the Arizona State University in Tempe, where her father had become a professor. Strojnik says her "first years in the US were nothing like the movies that the Hollywood film industry exported to Slovenia".

Strojnik, who had been the only female student in a department with 60 physicists, says she "lived in a man's world all her life: from growing up with four brothers to being the only or the first woman in many situations". "I was the first pregnant staff engineer at Honeywell. Old-fashioned engineers did not hide their discomfort at seeing my Goddess-of-Plenty figure."

The expert on infrared radiation and its technology started her career as the manager of the optics department at Rockwell International, later part of Boeing, continued at senior positions at aircraft engines and avionics manufacturer Honeywell, at the Jet Propulsion Laboratory at the California Institute of Technology, and as regents professor at the Optical Research Center in Leon, Mexico.

Strojnik, who is a fellow of the Optical Society of America (OSA) and of the International Society for Optics and Photonics (SPIE), has published over 100 refereed papers and is responsible for scores of editorial and organisational contributions in her field.

Her biggest achievement to date is the design, development and implementation of a novel method for autonomous optical navigation using star maps and an intelligent charge-coupled device (CCD)-based camera. The device guides robotic vehicles towards their interplanetary goals, which made for the first spacecraft to take decisions completely independently.

The invention, which has become, in one form or another, part of all commercial aircraft, was picked to guide the NASA Cassini mission (2005-2017) to the outer planets. Everybody has benefited from it as each mobile phone employs precise positioning of the GPS satellites to determine its own location to within a metre or two.

The breakthrough prompted the SPIE to make Strojnik in 1996 the first woman recipient of the prestigious George W. Goddard award. Moreover, NASA has awarded her eight Technology development certificates.

The achievement paved the way for Strojnik's future career, giving her near-complete independence in the choice of research projects and teaching load in Mexico, where she developed a specially modified difference interferometer meant to serve in the direct identification of extra-solar planets and other testing experimental setups.

The traditional methods leading to reported discoveries of hundreds of planets are indirect and may be considered unreliable. In scientific speak, the current techniques do not uniquely relate the cause (planet) and effect (detected signal).

In a popular technique, the planets are detected when a planet, moving between the star and the Earth, reduces the intensity of the light apparently emitted by a star. Strojnik jokingly says that "a witch on a broom" would cause the same intensity reduction. The witch, of course, is flying though the stratosphere of our atmosphere, which is why we do not see her.

Strojnik is a proponent of building an observatory on the far side of the Moon. This seems an unlikely feat, at least in the short-term. But the chances of the idea materializing has possibly received an unexpected boost recently, when the US government announced it was planning a comeback following the country's 45-year absence from the Moon.

"The next significant exploration goal for humanity will likely be to go to the Moon or to a planet in our own solar system and set up a colony there... This would be considered a practice run for the future space colonization outside our solar system," she said.

Strojnik is satisfied with the progress of her own instrument for the extra-solar planet detection.

"Currently, even the US funding agencies are interested in participating in its successful demonstration... Potential novel instruments continue to be built until such time as the technological, political and economical conditions are ripe. Just now, we may be coming to a time when some of the conditions to make a further leap in space exploration are becoming favourable again."

Strojnik has also been studying the scientific issues that form the basis of molecular life, including erroneous cellular development leading to cancer, a disease she has beaten several times. "I believe that cancer and I have made a pact of peaceful coexistence that the cancer has been honouring for over five years, allowing me to finish a few more things."

A mother of three daughters, whom she had to raise on her own after losing her husband early to aggressive multiple sclerosis, Strojnik recently told young visitors of the Slovenian Science Festival in Ljubljana, a science promotion event, that she felt "eternally young".

"It's because I've worked mostly with young people and have always been looking for new problems to crack with their help. There is just no time to ask the Mirror, Mirror-On-The-Wall for its truth."