March 1, 2024

Lunar science is entering an active new phase, with commercial launches of probes that will study the solar wind and observe the dark ages of the universe.

For the first time since 1972, NASA will conduct scientific experiments on the Moon in 2024. And thanks to new technologies and public-private partnerships, these projects will open up new realms of scientific possibility. As part of several projects launched this year, teams of scientists, including myself, will conduct radio astronomy from the south pole and the far side of the Moon.

NASA’s Commercial Lunar Payload Services Program, or CLPS, will use unmanned probes to conduct NASA’s first scientific experiments on the Moon in more than 50 years. The CLPS program differs from previous space programs. Instead of NASA building the landers and operating the program, commercial companies will do so in a public-private partnership. NASA has identified about a dozen companies to serve as suppliers of probes that will go to the Moon.

CLPS will send scientific payloads to the Moon in conjunction with the manned missions of the Artemis program.

NASA buys space on these probes for scientific payloads to fly to the Moon, and the companies design, build and maintain the probes, as well as contract with rocket companies for the launches. Unlike in the past, NASA is one of the customers and not the only driver.

CLPS releases

The first two CLPS payloads are scheduled to launch during the first two months of 2024. There’s the Astrobotics payload, which launched on January 8 before running into a fuel issue that shortened its journey to the Moon. Next comes the Intuitive Machines payload, scheduled to launch in mid-February. NASA also planned a few additional landings — about two or three per year — for each of the next few years.

I am a radio astronomer and co-investigator for NASA’s ROLSES program, also known as Radiowave Observations at the Lunar Surface of the photoElectron Sheath. ROLSES was built by NASA’s Goddard Space Flight Center and is led by Natchimuthuk Gopalswamy.

The ROLSES instrument will be released with Intuitive Machines in February. Between ROLSES and another mission scheduled to the far side of the Moon in two years, LuSEE-Night, our teams will land NASA’s first two radio telescopes on the Moon by 2026.

The Intuitive Machines payload preparing to be sent to Cape Canaveral.
Intuitive Machines, Inc.

Radio telescopes on the Moon

The Moon – particularly the far side of the Moon – is an ideal place to do radio astronomy and study signals from extraterrestrial objects like the Sun and the Milky Way. On Earth, the ionosphere, which contains the Earth’s magnetic field, distorts and absorbs radio signals below the FM band. These signals can get scrambled or not even reach the Earth’s surface.

On Earth there are also TV signals, satellite transmissions and defense radar systems making noise. To make more sensitive observations, it is necessary to go into space, far from Earth.

The Moon is what scientists call tidal locking. One side of the Moon always faces Earth – the “man on the Moon” side – and the other side, the other side, always faces away from Earth. The Moon has no ionosphere, and with about 2,000 miles of rock between Earth and the far side of the Moon, there is no interference. The radio is silent.

For our first mission with ROLSES, scheduled to launch in February 2024, we will collect data on the environmental conditions of the Moon near its south pole. On the surface of the Moon, the solar wind directly hits the lunar surface and creates a charged gas called plasma. Electrons detach from the negatively charged surface to form a highly ionized gas.

This doesn’t happen on Earth because the magnetic field deflects the solar wind. But there is no global magnetic field on the Moon. With a low-frequency radio telescope like ROLSES, we will be able to measure this plasma for the first time, which could help scientists figure out how to keep astronauts safe on the Moon.

When astronauts walk on the surface of the Moon, they pick up different charges. It’s like walking across carpet in socks: when you reach for a door handle, a spark can come out of your finger. The same type of discharge happens on the Moon from charged gas, but it is potentially more harmful to astronauts.

Solar and exoplanetary radio emissions

Our team will also use ROLSES to observe the Sun. The Sun’s surface releases shock waves that send out highly energetic particles and low radio frequency emissions. We will use radio telescopes to measure these emissions and see bursts of low-frequency radio waves from shock waves in the solar wind.

A lunar module on the gray surface of the Moon. The lander has a reflective golden square body, a black panel on the right side, and a white square top with two long, thin antennas on top.
The Intuitive Machines payload, which will contain materials for ROLSES, shown on the lunar surface in an illustration.
Intuitive Machines, Inc.

We will also examine Earth from the surface of the Moon and use this process as a model to observe radio emissions from exoplanets that may harbor life in other star systems.

Magnetic fields are important for life because they protect the planet’s surface from the solar/stellar wind.

In the future, our team hopes to use specialized arrays of antennas on the far side of the Moon to observe nearby star systems that are known to have exoplanets. If we detect the same type of radio emissions that come from Earth, it will tell us that the planet has a magnetic field. And we can measure the strength of the magnetic field to find out if it is strong enough to protect life.

Cosmology on the Moon

An artist's rendering of a small craft sitting on the gray surface of the Moon. The craft has a golden rectangular body with a black plate, a gray panel on the left side, and a silver rectangular top, with four long thin metal rods coming out of the top
LuSEE-Night, shown with its four antennas that will detect radio waves.
Firefly Aerospace

The Lunar Surface Electromagnetic Experiment at Night, or LuSEE-Night, will fly in early 2026 to the far side of the Moon. LuSEE-Night marks scientists’ first attempt at doing cosmology on the Moon.

LuSEE-Night is a new collaboration between NASA and the Department of Energy. The data will be sent back to Earth via a lunar-orbiting communications satellite, the Lunar Pathfinder, which is funded by the European Space Agency.

Because the far side of the Moon is uniquely radio silent, it is the best place to make cosmological observations. During the two weeks of lunar night that occur every 14 days, there is no emission from the Sun and there is no ionosphere.

We hope to study an unexplored part of the early universe called the dark ages. The Dark Ages refer to before and just after the formation of the universe’s first stars and galaxies, which is beyond what the James Webb Space Telescope can study.

During the Dark Ages, the Universe was less than 100 million years old – today the Universe is 13.7 billion years old. The universe was full of hydrogen during the Dark Ages. This hydrogen radiates through the Universe at low radio frequencies, and when new stars light up, they ionize the hydrogen, producing a radio signature in the spectrum. Our team hopes to measure this signal and learn how the Universe’s first stars and galaxies formed.

There are also many potential new physics that we can study in this last unexplored cosmological epoch of the universe. We will investigate the nature of dark matter and early dark energy and test our fundamental models of physics and cosmology in an unexplored era.

This process will begin in 2026 with the LuSEE-Night mission, which is both a fundamental physics experiment and a cosmology experiment.

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