Lunar labs? Moonshine no more

There has lately been a resurgence of interest in exploring our nearest celestial neighbour with unmanned missions even from Asian countries like India and China.

It is well over 45 years since the last lunar landing mission returned with three astronauts. It happened in December 1972.

So far, 12 astronauts have walked on the moon in six manned missions. They have brought back several hundred pounds of lunar rock and traversed several kilometres over the lunar terrain in wheeled rovers.

There has lately been a resurgence of interest in exploring our closest celestial neighbour with unmanned missions even from Asian countries like us and China. 

The moon has been recognised for quite some time now as an ideal locale for various scientific studies, especially astronomy. There have been plans to set up radio telescopes in certain lunar regions, which would be free of terrestrial radio cacophony (of human origin) and optical telescopes (including liquid mirror telescopes), which would be free of the obscuring effects of the dense terrestrial atmosphere.

There are recent reports of even private operators’ interest in deploying radio arrays to the vicinity of the lunar South Pole, to those regions that have perpetual sunlight ideal for continuous solar power.

Technological progress in new materials and instrumentation has indicated that setting up laboratories or observatories on the moon but lead to moon science (i.e. outposts on the moon could considerably increase our astronomical knowledge and also result in developments in exploiting solar power with spin-offs in biology, geology etc).

Matching interests

There is increasing seriousness in harnessing the moon for science. We have the example of Antarctica, which was practically untouched for at least half a century after the intrepid early explorers. It has now become a mushrooming colony of year-long laboratories, observatories (Dome C, for example) in various research areas (including exotic fields like neutrino astronomy and south pole Telescope for studies of the microwave background) manned by tens of thousands of scientists in summer and thousands during the long winter. 

Is the moon also fated to follow Antarctica in the setting up of several scientific stations exploring several scientific areas? It seems plausible judging from the current level of interest and proposed plans.

Some years ago, the International Astronomical Union’s (IAU) working group on astronomy from the moon pointed out several areas of research which could ideally be done there.

For instance, radio astronomy, at low frequencies, has become impossible on Earth as radio waves ubiquitously spewed out by our personal gadgets and gizmos drown out all celestial signals. Sometime ago, Motorola had to change its operating frequencies (for the Iridium satellites) to avoid jamming some crucial radio astronomical frequencies like the hydroxyl line. The far side of the moon is ideally perfect to shield radio telescopes from all terrestrial cacophony as it is permanently turned away from the Earth.

Being in constant shadows, it could be ideal for an array of radio telescopes, which when deployed by robots in containers holding several large dishes, could form a several kilometre-wide hexagonal arrays. The dishes would relay their signals (by laser) to a central hub, thus forming a low-frequency radio telescope with the same resolution as a 20-km dish. The low-frequency radio spectrum, supposed to be the last unexplored window in astronomy, and the interference-free ambience would be ideal to search for signs of extraterrestrial intelligence (ETI) (safe from all human radio interference). 

For optical telescopes, the moon offers all advantages of operating in space — that is there is no atmosphere to blur out the stars and available sites where nights are long and uninterrupted, yet there is constant solar power.

The perishing low temperatures inside the craters are particularly useful for infra-red astronomy, apart from spurring research in low-temperature research including superconducting power systems. There is no cost for refrigeration. Moreover, the moon is seismically inert, which would help precision experiments in geology, seismology etc.

Telescopes and instruments in free space (as distinct from the solid lunar surface) have a drawback — aligning them with each other and correlating signals require complicated systems of corrections and measurements with continuous monitoring. On the moon’s surface, this is not required. 

An array of optical telescopes on the moon could be spread over a wide area so that such a system could have a resolution of a single mirror.

The Shackleton crater at the lunar South Pole is frigid and in perpetual darkness, ideal for the infrared telescope. Water-ice present could provide fuel cell power.

The Malapert Mountain, a five-km peak on the edge of a crater close to the South Pole, is in constant view of the Earth, enabling continuous radio communication, and as it receives solar radiation most the time, it’s an ideal site to generate solar power for instruments and possible lunar habitable colonies.

The South Pole-Aitken basin, more than 10 km deep, is the deepest lunar region and the largest impact region in the solar system.

It could hold records of the earliest fossil life (prior to three billion years), which could have been blasted off from Earth during the Great Bombardment era when the planet and its natural satellite were subjected to intensive impacts from planetesimals (asteroids). Such fossil life would have been completely destroyed on Earth but could be preserved in the pristine erosion-free lunar environment.

There could be evidence of the debris from the asteroid that destroyed life on Earth (including dinosaurs) during the Cretaceous Period.

Some of the debris carrying fossil would have landed on the moon. So, there is scope for much research on archaeon biology.

Also, the effects of low gravity on astronauts spending longer periods in lunar bases could be studied. As it requires much less energy to launch spacecrafts from the moon, lunar bases could be the stepping stones for inter-planetary voyages. Mineral-rich areas have been identified so that spacecrafts can be built.

There are also plans to have a large liquid mirror telescope on the moon (with its low gravity). 

(The writer is with Indian Institute of Astrophysics, Bengaluru)

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