A 4G network on the Moon is bad news for radio astronomy
As you drive down the road leading to Jodrell Bank Observatory, a sign asks visitors to turn off their mobile phones, stating that the Lovell telescope is so powerful it could detect a phone signal on Mars.
Radio telescopes are designed to be incredibly sensitive. To quote the legendary astronomer Carl Sagan, “The total amount of energy from outside the solar system ever received by all the radi
o telescopes on the planet Earth is less than the energy of a single snowflake striking the ground.”
The total energy now is probably a few snowflakes’ worth, but nevertheless it is still true that astronomical radio signals are typically magnitudes smaller than artificial ones. If Jodrell Bank could pick up interference from a phone signal on Mars, how would it fare with an entire 4G network on the Moon?
That is the issue that is worrying astronomers like me, now that Nokia of America has been awarded US$14.1m (£10.8m) for the development of the first ever cellular network on the Moon. The LTE/4G network will aim to facilitate long term lunar habitability, providing communications for key aspects such as lunar rovers and navigation.
Radio frequency interference (RFI) is the long-term nemesis of radio astronomers. Jodrell Bank – the earliest radio astronomy observatory in the world still in existence – was created because of RFI. Sir Bernard Lovell, one of the pioneers of radio astronomy, found his work at Manchester hampered by RFI from passing trams in the city, and he persuaded the university’s botany department to let him move to their fields in Cheshire for two weeks (he never left).
Since then, radio telescopes have been built more and more remotely in an attempt to avoid RFI, with the upcoming Square Kilometre Array (SKA) telescope being built across remote areas of South Africa and Australia. This helps to cut out many common sources for RFI, including mobile phones and microwave ovens. However, ground-based radio telescopes cannot completely avoid space-based sources of RFI such as satellites – or a future lunar telecommunications network.
RFI can be mitigated at the source with appropriate shielding and precision in the emission of signals. Astronomers are constantly developing strategies to cut RFI from their data. But this increasingly relies on the goodwill of private companies to ensure that at least some radio frequencies are protected for astronomy.
A long-term dream of many radio astronomers would be to have a radio telescope on the far side of the Moon. In addition to being shielded from Earth-based signals, it would also be able to observe at the lowest radio frequencies, which on Earth are particularly affected by a part of the atmosphere called the ionosphere. Observing at low radio frequencies can help answer fundamental questions about the universe, such as what it was like in the first few moments after the big bang.
The science case has already been recognised with the Netherlands-China Low Frequency Explorer, a telescope repurposed from the Queqiao relay satellite sent to the Moon in the Chang’e 4 mission . Nasa has also funded a project on the feasibility of turning a lunar crater into a radio telescope with a lining of wire mesh.
Read more: China lands on the far side of moon – here is the science behind the mission
It’s not just 4G
Despite its interest in these radio projects, Nasa also has its eye commercial partnerships. Nokia is just one of 14 American companies Nasa is working with in a new set of partnerships, worth more than US$370m, for the development of its Artemis programme, which aims to return astronauts to the Moon by 2024.
The involvement of private companies in space technology is not new. And the rights and wrongs have long been debated. Drawing possibly the most attention has been SpaceX’s Starlink satellites, which caused a stir among astronomers after their first major launch in 2019.
Read more: Space junk: Astronomers worry as private companies push ahead with satellite launches
Images quickly began to emerge with trails of Starlink satellites cutting across them – often obscuring or outshining the original astronomical targets.
An artist’s impression of the planned SKA-mid dishes in Africa. SKA Organisation, CC BY
Astronomers have had to deal with satellites for a long time, but Starlink’s numbers and brightness are unprecedented and and their orbits are difficult to predict. These concerns apply to anyone doing ground-based astronomy, whether they use an optical or a radio telescope.
A recent analysis of satellite impact on radio astronomy was released by the SKA Organisation, which is developing the next generation of radio telescope technology for the Square Kilometre Array. It calculated that the SKA telescopes would be 70% less sensitive in the radio band that Starlink uses for communications, assuming an eventual number of 6,400 Starlink satellites.
As space becomes more and more commercialised, the sky is filling with an increasing volume of technology. That is why it has never been more important to have regulations protecting astronomy. To help ensure that as we take further steps into space, we’ll still be able to gaze at it from our home on Earth. Emma Alexander does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Author: Emma Alexander, PhD Candidate in Astrophysics, University of Manchester
|Five innovations that could shape the future of rail travel (2020-10-19)||aapsky/ShutterstockWhat will the future of public transport look like? The major projects being planned today such as the UKs HS2 high-speed rail network arent fundamentally different to whats been built over the last 30 years Maglev trains are largely confined to niche projects in China Hyperloop remains an unproven glimmer in Elon Musk and Richard Bransons eyes The likes of HS2 can deliver consi..|
|From Space Force to Artemis: what Joe Biden presidency may mean in orbit and beyond (2020-11-11)||Mars 2020 Perseverance space mission launches from Kennedy Space Center CRISTOBAL HERRERA-ULASHKEVICH/EPA-EEDonald Trump set bold goals for space exploration during his time in office from crewed missions to the Moon and Mars to a Space Force By contrast his successor Joe Biden has been relatively quiet on space policy So how is space exploration likely to change going forward? It is clear is that..|
|When did humans first go to war? (2020-11-09)||Cain killing Abel Titian/WikimediaWhen modern humans arrived in Europe around 40000 years ago they made a discovery that was to change the course of history The continent was already populated by our evolutionary cousins the Neanderthals which recent evidence suggests had their own relatively sophisticated culture and technology But within a few thousand years the Neanderthals were gone leaving ou..|
|COVID-19: four ways to respond to vaccine sceptics – and maybe even convince them (2020-11-25)||There are productive ways to talk to people you disagree with CREATISTAFor most of the 20th century more than 60000 people died in the US from polio diphtheria and small pox each year In 2016 the American death toll from these diseases was zero Around the globe two to three million deaths from these diseases and others including measles rubella and tetanus are prevented each year These remarkable .. COVID-19: four ways to respond to vaccine sceptics – and maybe even convince them|
|The way we use data is a life or death matter – from the refugee crisis to COVID-19 (2020-11-12)||In moments of crisis we often turn to data in an attempt to both understand the situation we are in and to look for answers of how to escape In response to COVID-19 governments around the world have employed algorithms used data from apps installed on our phones alongside CCTV facial recognition and other data gathering tools to fight the pandemic Data is being used to drive the daily movements of..|
|Curious Kids: If the Earth is spinning all the time, why don’t things move around? (2020-11-27)||The Earth in space Elements of image furnished by NASA Volodymyr Goinyk/ShutterstockIf the Earth turns all the time then why isnt the door where the stairs are sometimes? Katie aged six Saltburn-by-the-Sea UK The Earth is always spinning Every day you are turned upside down and back again You will also probably have travelled thousands of kilometres and as much as 40000 kilometres if you live near..|
|Life on Earth: why we may have the Moon’s now defunct magnetic field to thank for it (2020-10-15)||Photo of a nearly full Moon shining brightly on the Earths atmosphere taken from the International Space Station NASAThe habitability of a planet depends on many factors One is the existence of a strong and long-lived magnetic field These fields are generated thousands of kilometres below the planets surface in its liquid core and extend far into space shielding the atmosphere from harmful solar r..|
|Curious Kids: How did some animals evolve wings to fly? (2020-10-22)||Hybrid parrots in Costa Rica Ondrej Prosicky/ShutterstockHow did some animals form wings to fly? Year Five class London UK Perhaps the first thing you notice when you see a bird is its amazing ability to fly Modern birds fly using their arms which have feathers and very strong flight muscles But the ancestors of todays birds couldnt fly Birds evolved from a group of dinosaurs called theropods whic..|
|Boeing 737 Max: why was it grounded, what has been fixed and is it enough? (2020-11-27)||The Boeing 737 Max began flying commercially in May 2017 but has been grounded for over a year and a half following two crashes within five months On October 29 2018 Lion Air Flight 610 took off from Jakarta It quickly experienced problems in maintaining altitude entered into an uncontrollable dive and crashed into the Java Sea about 13 minutes after takeoff Then on March 10 2019 Ethiopian Airline..|
|The threat of ‘killer robots’ is real and closer than you might think (2020-10-15)||Media Whalestock/ShutterstockFrom self-driving cars to digital assistants artificial intelligence AI is fast becoming an integral technology in our lives today But this same technology that can help to make our day-to-day life easier is also being incorporated into weapons for use in combat situations Weaponised AI features heavily in the security strategies of the US China and Russia And some exi..|