Meet a NASA Space Scientist
Dr. Jennifer Stern is a Space Scientist at the NASA Goddard Space Flight Center in Greenbelt, Maryland. Katya Vines, a Science Curriculum Developer at the Smithsonian Science Education Center, recently interviewed Jen about her role on the Mars Curiosity Rover team and her path to becoming a space scientist. Some of Jen's answers may surprise you!
What was your favorite class in school?
My favorite classes were actually visual arts and English. I loved painting with oils and did studio art every semester in school. In English, I mostly enjoyed Shakespeare and the Romantic poets.
What inspired you to pursue a career in science?
I wanted a career in which I could spend time outdoors and enjoy nature. I was curious about the natural world and also felt compelled to understand how we, as humans, are impacting it.
What do you love most about science?
I think science is very creative. Every answer brings more questions. The kind of science I am involved with is truly exploration because we're measuring things no one else has measured. In addition, the measurements we do get from Mars and other planets are few and far between, so there's a lot of creative problem solving in order to come up with the story to explain the data.
You studied Geology followed by a PhD in Geochemistry. How does a geologist become a space scientist?
I am still a geologist, specifically a planetary geochemist. In graduate school I carried out research to understand how carbon and other nutrients were cycled in the Florida Everglades. I got interested in the field of astrobiology, which involves looking for traces of life in the universe and understanding how life originated on Earth. All of the techniques I used to trace biological processes in Earth environments can also be used to look for traces of life on other planets, so this is how I decided I wanted to apply my work.
You are part of the Mars Curiosity Rover team. What is your role on this team?
Our team at NASA Goddard has an instrument on the Mars Curiosity Rover called Sample Analysis at Mars (SAM), which analyzes the molecules released from heating of rock samples in our onboard ovens as well as the composition of the atmosphere of Mars. As part of the SAM team I help plan experiments to be performed on Mars to answer science questions, I analyze the data we receive after we run an experiment on Mars, and I report this information to the larger Curiosity team and to the rest of the scientific community. As part of the larger Curiosity team I also help make decisions about what kinds of samples to target and where to drive on Mars.
How does analyzing rocks on Mars differ from analyzing rocks on Earth?
A geologist in the field gets to look at a rock, turn it around in his or her hands, and chip off pieces to get to what's inside and untouched by any alteration. Most importantly, the geologist can take the rock back to the lab and do many, many analyses on it. On Mars, you only get maybe one chance to make the measurement, and then the rover moves on and those samples are gone. In the beginning of the mission, we ran multiple analyses on the same sample but decided this took too long, so now our instrument only gets one shot to analyze the target rock.
What questions does Curiosity help scientists to answer?
We are trying to understand whether the conditions ever existed on Mars that would have been hospitable to life, not only in the past, but also present. In addition, we are trying to understand what organic molecules might be present on the surface of Mars.
What tools does Curiosity have to help scientists answer these questions?
We have over 17 different cameras, instruments to measure weather and radiation of present day Mars, a tool that acts like a geologist's hand lens to magnify textures on samples, and several instruments to measure the chemical makeup of the surface rocks from a distance. Finally, there are two instruments in the belly of the rover that receive drilled or scooped samples from the rover arm and do mineralogical and molecular analysis of the samples. SAM is one of these two instruments.
How does Curiosity transmit data from Mars to scientists on Earth?
The rover stores data to be uploaded to one of the two satellite instruments orbiting Mars. These satellites send data back through the "Deep Space Network" to one of three large antennas on Earth, which are located in California, Spain, and Australia.
What conclusions have scientists drawn from analyzing these data?
We know that there were environments on Mars that were once wet, with both flowing and calm waters, and that many nutrients that are used in biology were present, such as carbon, nitrogen, oxygen, phosphorus, hydrogen, and sulfur. We also know that Mars once had a much thicker atmosphere but long ago, much of this was lost to space.
Your team recently discovered nitrates on Mars. Why is this an important discovery?
Nitrate is a form of nitrogen that can be readily used by life. All life on Earth uses nitrogen as a nutrient to make amino acids and nucleic acids, as well as other biomolecular building blocks. Life on Earth has evolved ways to take nitrogen out of the atmosphere and turn the nitrogen into something usable. On Mars, finding nitrate means that nitrogen could have been used by life, had life been present at any time in Mars' history.
What has been the biggest setback during your time working on Curiosity? How did you and the team overcome this?
No one large setback has occurred. We have had small problems with the instrument that have delayed some analyses, but these have been resolved. Probably the hardest thing to come to terms with during the mission for the team has been how long everything takes. We have been driving to Mt. Sharp, our target, for the last two years and have finally reached the lowest part of the mound. Sometimes it's hard to keep momentum at this pace, but there is always something new being discovered, either by us or by other missions, so it is never boring.
What has Mars exploration taught us about Earth?
Mars is a great analogy for early Earth, before the evolution of biology. It's very difficult to study non-biological processes on Earth because biology overprints everything. So, to better understand some of the chemistry that may have been active on the early Earth, we can look at early Mars, which is very well preserved since Mars doesn't have active tectonics to recycle rocks. Rocks from ancient Earth have, for the most part, been recycled back into the mantle, buried, or eroded.
What would be the challenges of a manned mission to Mars?
There are many challenges for a manned mission to Mars. To put humans on Mars, you also need to bring their air, food, and water. Landing these very heavy things presents an engineering challenge on Mars. Because of Mars' thin atmosphere, there is little to slow down objects entering it, so the chances of a heavy object crashing on impact is very high. Curiosity, weighing about a ton, was the first step to landing heavy objects on Mars. Also, the trip to Mars exposes humans to a lot of ionizing radiation, which results in cell damage. Humans would need to be protected from the large dose of radiation they would receive on the trip to Mars.
If you had to travel to Mars with three other people, who would you choose?
That's a difficult question. Spending several months cooped up with three other people would be very difficult. I'd probably want a very close friend, and then possibly two strangers who are easy to get along with. That way there will be a lot to learn about them on the journey!
Where in the universe do you think we are most likely to find other life forms first?
I would guess Mars or one of the icy moons such as Europa or Enceladus could be likely places to find other life forms.
What is your favorite science fiction book?
My favorite sci-fi series is called Hyperion by Dan Simmonds.
What do you think young scientists today might be investigating on Mars 30 years from now?
I think they will be focused on human exploration, how to convert the raw materials in the Martian atmosphere and on the surface into breathable air and drinkable water, as well how to grow food there. This is very different than the basic science we are doing today on Mars to better understand the history of the planet's surface and atmosphere.