Posted: 13 July 2017, 11:30 a.m. EDT
Panelists: Moderator Lee Mason, principal technologist, Space Technology Mission Directorate, NASA; Stephen Hoffman, senior systems engineer for the exploration mission planning office, NASA’s Johnson Space Center; Thomas Kerslake, power system engineer, NASA’s Glenn Research Center; Humphrey "Hoppy" Price, chief engineer, Mars Exploration Program, NASA’s Jet Propulsion Laboratory; Larry Trager, director of advanced power systems, Aerojet Rocketdyne
Tom Risen, Aerospace America staff reporter
Durable power sources will be crucial to keeping astronauts alive on the frozen surfaces of the moon or Mars, a panel of NASA engineers and aerospace executives said July 12 during the “Planetary Surface Power” discussion at the 2017 AIAA Propulsion and Energy Forum in Atlanta.
The power sources and electronics for human exploration on these worlds will face battles against time and the elements. Mars has a thin atmosphere, but it also has dust storms that can last for three months and cover the entire planet, said Stephen Hoffman, senior systems engineer for the exploration mission planning office at NASA’s Johnson Space Center. That’s a problem for any habitat that would use solar power, he said, because the solar cells would become coated with dust, and the storms would limit the amount of sunlight reaching the surface of the red planet.
Decaying plutonium radioisotopes generated heat to provide electricity for Viking probe missions to Mars and Apollo missions that took humans to the moon, so they are a proven and durable method to power a human habitat, said Larry Trager, director of advanced power systems at Aerojet Rocketdyne. The problem with radioisotopes is that plutonium is in short supply, so the power source would have to be very efficient, he said.
Participants in the panel discussion, "Planetary Surface Power,” July 12 at the 2017 AIAA Propulsion and Energy Forum in Atlanta.
The solar-powered Opportunity rover has survived on Mars for 13 years despite these storms thanks to its backup battery power, but a human camp will need much more electrical power, said Humphrey Price, chief engineer of the Mars Exploration Program at NASA’s Jet Propulsion Laboratory.
Planetary power needs a long shelf life because it will take about four years between the time rockets deliver the gear to Mars and the time astronauts arrive, and the power source needs to be able to operate for many years after that, Hoffman said. NASA is considering operating a single Mars habitat for up to 500 days and sending multiple missions there.
Because of this, Hoffman said, choosing a landing site will be critical. He explained the poles of Mars could have ice water, which would be a potential source for hydrogen-powered fuel cells, but that could be difficult for solar power and human habitation because seasons on some areas of Mars can include long periods of daylight or darkness. The equator region of Mars is where NASA has sent all its rovers and has more moderate temperatures than other regions of the planet, Hoffman said. However, a landing site near the equator would not be exempt from the dust storms that would limit solar power capability, so nuclear power would be needed for long missions, he said.
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