Heading to Lake of Death
I'm suddenly excited about the one-way trip to Lake of Death, latitude 45 degrees north, in summer 2021. Pandemic protocols may have delayed and complicated travel preparations, but the luggage is ready. Bring on the sun and temperature extremes.
If you're not familiar with the Lake of Death site (Lacus Mortis in Latin), perhaps that's because nothing from the U.S. has been near this chunk of uninhabited real estate in about 50 years. It's on the moon. The last nearby visit was when Apollo 17 astronauts blasted off the Sea of Tranquility in December 1972.
This year's trip is a commercial spacecraft carrying NASA payloads that are preparing for sustained habitation on the moon under the NASA Artemis program.
In mid-2021 the Pittsburgh-based company Astrobotic will send its Peregrine Lander (its first of multiple missions) to Lacus Mortis with a suite of NASA experiments onboard. Among them is the Photovoltaic Investigation on the Lunar Surface (PILS). Developed at NASA Glenn Research Center--whose expertise includes power, energy storage and conversion--PILS will be testing the extreme environment under which solar panels would operate on the moon.
NASA writes, "The PILS platform, while relatively small and lightweight, will provide a flight demonstration of multiple solar cell technologies from multiple companies that could be used for future lunar missions." The solar charging experiment will test high voltage solar arrays that will power future lunar surface assets.
Keeping an outpost alive through the lunar phases--weeks of relentless sunshine (260 degrees F) followed by weeks of utter darkness (minus 280 degrees F)--requires reliable energy for both the people and the experimental components. “PILS is just the first step in better understanding the environment in which solar arrays and power systems will exist on the Moon as we work towards powering a sustainable, long-term human-lunar presence there,” says Tim Peshek, PILS co-principal investigator.
We haven't been back to the moon in nearly 50 years, and the missions of today serve the vision for tomorrow, so it's exciting to see that the return incorporates the talents of emerging young engineers. PILS has been surprisingly under the radar of NASA media, with few links to related content found in an online search. Fortunately, an exception is the handiwork of Greeta Jose Thaikattil, a recent graduate from Cleveland State University.
In her 2020 master thesis Thermal Analysis and Design of the Photovoltaic Investigation on Lunar Surface (PILS) Payload, Thaikattil describes the thermal model used to analyze how the solar panels will fare in the extremes of cold and hot in space. "The results," she concludes, "show that the overall thermal design is successful in keeping all critical components within their operational temperature range throughout the entire mission." Months later, the lead thermal engineer's research will be put to the test.
The environments on earth and on the moon are significantly different, and any solar array on the moon must meet the demands of extreme temperatures, radiation, weight considerations, and more. Yet NASA advancements in space inevitably translate to gains in earthbound spinoffs.
As we earthlings look at the waxing moon we can imagine PILS on its surface, a precursor to the return of people. It's been a long time coming--50 years!--but it will show the USA is back with purpose. In confronting climate change on earth, we can welcome concurrent advances in and insights from solar technology from the moon.
Volcanoes in Lacus Mortis
PILS built despite challenges
LORC: A gathering in Lacus Mortis
1990 paper Photovoltaic Power for a Lunar Base
http://andrewplanck.com/moon-craters-lacus-mortis-and-burg/ Two Moon Craters with Unique Features: Lacus Mortis and Bürg; Andrew Planck
Image of Lacus Mortis from Sky & Telescope gallery
Moon temp: Zero degrees Celsius, plus or minus 260 degrees!