Photovoltaic Investigation on the Lunar Surface (PILS)¶
Blue Ghost Mission 3 · manifested · NASA payload
A small solar-cell test bed (about 4.3 kg, 30 x 30 cm) that measures current-voltage curves and temperatures of several cell types through a lunar day: state-of-the-art and next-generation multi-junction cells and low-cost silicon cells. A small string of cells with conductive coverglass measures how much electric charge builds up on a solar array on the Moon, to guide the design of future high-voltage lunar arrays.
PI: Jeremiah McNatt (NASA Glenn); Timothy Peshek was co-PI on the Peregrine version
Built by: NASA Glenn Research Center (in-house) (NASA center)
| Technology | technology demonstration (solar cells and array surface charging) |
| Moon Base need | #0901, DN-011 L (Partly NASA's link. NASA's CP-21 page says solar power is planned as the primary energy source for future exploration and habitation, and that PILS's lessons are 'an important step' toward a long-term human presence. The ties by ID are the study's reading: array performance in the lunar environment (#0901, under the guide's 'Solar power' challenge, which asks for 'array performance' and systems robust to the environment) and surface charging of arrays (DN-011 L, the surface plasma). Gruithuisen is a northern near-side site; the gaps are written for the South Pole.) |
| Route onto CLPS | NPLP; NASA-Provided Lunar Payloads: the team answered SMD's 2019 request for payloads ready to fly with little development; NASA awarded it in March 2019 as one of 12 NASA payloads. The 21 February 2019 NPLP list names a 'Solar Cell Demonstration Platform for Enabling Long-Term Lunar Surface Power'; whether that is PILS is not stated. Assigned to Astrobotic's Peregrine Mission One (January 2020); PILS was shipped to Astrobotic in December 2021 and fitted to a sidewall panel in January 2022. NASA took it off Peregrine in 2023, to be reallocated, and assigned it to Firefly's CP-21 on 18 December 2024.; 2019-03 |
| Timeline | first funding 2019-03 (NPLP award); first flight test No flight of PILS itself; parent platform on MISSE-5 from 2005-07-26; selected 2019-03 (NPLP); assigned to Peregrine 2020-01-22; delivered to Astrobotic 2021-12; removed 2023; task order CP-21 to Firefly 2024-12-18; launch Not yet launched. Landing targeted for 2028. (In 2020 NASA expected a 2021 launch on Peregrine.); landing not in public sources |
| On the Moon | not yet flown |
| FO | none |
Flights before the Moon¶
- ISS or MISSE: MISSE-5 on the ISS exterior (Forward Technology Solar Cell Experiment, FTSCE), launched on STS-114, 2005-07-26 launch; about one year on orbit. The MISSE solar-cell flight test platform PILS is based on: Glenn designed and built its data-acquisition electronics, which traced current-voltage curves, temperatures and sun angle for many cell types in orbit, with the Naval Research Laboratory and the Naval Academy. Michael Krasowski of Glenn worked on both FTSCE and PILS. A predecessor platform, not PILS hardware.
"MISSE-5 was launched aboard the Shuttle return to flight mission (STS-114) on July 26, 2005 and deployed on the exterior of the International Space Station (ISS)."
— NTRS 20090022300, Introduction (Walters et al., SPRAT XIX)"Data-acquisition electronics designed, manufactured, programmed and tested by engineers and technicians at Glenn."
— NTRS 20050217095, Glenn Research and Technology 2004"Heritage on “Materials on the International Space Station Experiment” (MISSE) solar cell flight test platform"
— NTRS 20210010667, slide 4"Greeta J. Thaikattil, Michael J Krasowski, Amy R. Stalker"
— NTRS 20220007414, author list (PILS poster, PVSC 2022)
- ISS or MISSE: Robotic Refueling Mission (RRM) solar cell experiment on the ISS (date not given), not in public sources. A later ISS solar-cell experiment that the PILS team shows as prior work, designed from MISSE heritage hardware. The slides give no date or results.
"Robotic Refueling Mission (RRM) Solar Cell Experiment on International Space Station designed from MISSE Heritage hardware and experience"
— NTRS 20210010667, slide 8
Heritage hardware¶
- flown platform design: PILS is based on Glenn's MISSE solar-cell flight test platform; NASA calls it 'based on an International Space Station test platform'. Cells on the Peregrine version: Spectrolab UTJ triple-junction (with conductive coverglass for the charging experiment), SolAero IMM-alpha five-junction, and ASU silicon heterojunction cells, among others. Ground tests: thermal vacuum, random vibration, EMI.
"The concept was based off a heritage Materials on the International Space Station Experiment (MISSE) solar cell flight test platform"
— NTRS 20220013363, McNatt, PILS and VSAT overview"The flight hardware was tested in the GRC Structural Dynamics Laboratory under random vibe"
— NTRS 20220013363
Funding before the lunar flight¶
- NASA SMD, Lunar Discovery and Exploration Program, through NPLP; built in-house at Glenn, so no contract appears in USAspending (a search found none). The team's budget was USD 1.58 million for FY2019-2022: a budget figure from the team's own slides, not an obligation record. Funding for the Blue Ghost 3 flight is not in public sources. (NASA SMD LDEP / NPLP; FY2019-2022): amount not in public sources
"Budget: $1.58M FY19-22"
— NTRS 20210010667, slide 4"PILS proposed to Lunar Development Exploration Program (LDEP) call"
— NTRS 20210010667, slide 4 (as printed)
How it got onto CLPS¶
"Payload was awarded in March 2019, due in November 2020 (Rapid!)"
— NTRS 20210010667, slide 7"The Solar Cell Demonstration Platform for Enabling Long-Term Lunar Surface Power will demonstrate advanced solar arrays for longer mission duration."
— NASA Selects Experiments for Possible Lunar Flights in 2019 - NASA, release of 21 Feb 2019"PILS is a technology demonstration that is based on an International Space Station test platform for validating solar cells that convert light to electricity."
— First Commercial Moon Delivery Assignments to Advance Artemis - NASA, 22 Jan 2020, under Astrobotic Payloads"PILS was shipped to Astrobotic in December 2021 and physically integrated onto the sidewall panel in January 2022"
— NTRS 20220011446, McNatt, SPRAT talk, 2022"Photovoltaic Investigation on Lunar Surface (PILS) - Glenn Research Center (GRC)"
— TO2-AB Science Payloads - NASA Science, payloads 'being reallocated to future lunar delivery missions', update of 6 Apr 2023"will carry a set of the latest solar cells for a technology demonstration of light-to-electricity power conversion for future missions"
— More NASA Science, Tech will Fly to Moon Aboard Future Firefly Flight - NASA, release of 18 Dec 2024
On the Moon¶
Built and delivered for Peregrine by the end of 2021, then taken off that lander in 2023; now planned for the Gruithuisen Domes in 2028. Whether the 2021 flight unit flies as is, or with newer cells, is not stated.
"PILS contains a small array of different solar technologies."
— CLPS CP-21 Science - NASA Science
FO's role¶
Grade: none. No FO project, flight or report names PILS or its Glenn team (McNatt, Peshek, Krasowski and others); the study searched the 430 FO TechPort records, FO's reports and FO's pages. PILS's flight heritage is MISSE-5 (2005), before FO began selecting NASA-led MISSE payloads (FO's FY2017 report says it manages that selection). Topic-only FO work, not links: FO's balloon calibration of space solar cells for The Aerospace Corporation (TechPort 94141), and Marshall's LISA-T solar cells selected through FO for MISSE-10. The study's earlier traceback grade (none found) stands.
"No FO flight of PILS or its Glenn team."
— earlier finding of this study (not a public source)
Who built it¶
"PI: Jeremiah McNatt, Glenn Research Center"
— CLPS CP-21 Science - NASA Science"PIs (McNatt/Peshek) responded to a Request for Payloads (RFP) for the Development of NASA Provided Lunar Payloads (NPLP)"
— NTRS 20210010667, slide 6 (Peshek, March 2021)"says Tim Peshek, another principal investigator"
— Solar Power Investigation to Launch on Lunar Lander - NASA, NASA Glenn article, 16 Jul 2020
Moon Base need¶
"We plan on using solar power as the primary energy resource for future experiments, exploration, and human habitation"
— CLPS CP-21 Science - NASA Science"Lessons we learn from PILS will be an important step as we work towards a long-term human presence on the Moon."
— CLPS CP-21 Science - NASA Science"Deploying systems to generate, store, and distribute solar power requires precise knowledge of lighting conditions and array performance, as well as systems robust to the lunar environment."
— Moon to Mars knowledge base: Moon Base technology and knowledge challenges, Associated challenges, Solar power"Determine charge buildup on solar arrays and arcing hazards in the lunar environment"
— NTRS 20210010667, PILS Objectives
Open questions¶
- Is PILS the 'Solar Cell Demonstration Platform for Enabling Long-Term Lunar Surface Power' on NASA's February 2019 NPLP list? The names differ; NASA does not say.
- Does Blue Ghost 3 carry the PILS unit delivered for Peregrine in 2021, or a rebuilt one with newer cells? NASA's 2024 release says 'the latest solar cells'.
- Total NASA cost of PILS, including the work since 2022: not in public sources.
- Did the PILS cells or charging circuit fly on any FO or other suborbital test? Not in public sources. The 2022 slides say the early concept used 'high altitude flight calibration holders' (dropped for mass); whether PILS cells were calibrated on high-altitude flights is not stated.