4G LTE networks are well established here on Earth, but what does it take to translate cellular technology for applications on the lunar surface?

Nokia Bell Labs Thierry Klein says hes what some might call a space geek and while hes never travelled into orbit, a planned mission with NASA to establish an LTE network on the Moon brings him just a little bit closer.  
4G LTE networks are well established here on Earth, but what does it take to translate cellular technology for applications on the lunar surface?
FierceWireless spoke with Klein, head of the Enterprise and Industrial Automation Research Lab at Nokia Bell Labs, to find out. 
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For starters, it takes a lot of testing. When a cell site goes down or something isnt working right in a terrestrial network, queue up the technician or engineering crew to go make a fix. On the Moon, though, help isnt exactly a truck roll (or even rocket launch) away.
You can never test enough, Klein told Fierce.
Its fortunate then that the latest mission with NASA isnt Nokias first foray into lunar LTE. The Finnish vendor was the technology partner for an earlier privately funded project in 2018 with Vodafone and Audi to put LTE on the Moon.
That mission never flew, but Nokia already built an LTE system for that purpose. It set up configurations exactly as what would be used on the Moon, to test performance, range, throughput and more. About 25 tests were conducted in environmental chambers, according to Klein, for extreme conditions and stressors like shock, vibration, operation in a vacuum, thermal, and radiation. 
The new project is part of NASAs Artemis program, and Nokia won a $14.1 million award for its winning Tipping Point proposal that the space program solicited to help develop technologies with the goal of sustainable human operations on the lunar surface by 2030. 
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Now, however, Nokia needs to integrate the equipment with a lunar lander developed by Houston-based Intuitive Machines and theres still development and testing to be done to align with requirements for the specific mission at hand which, while similar, is also unique.
Thats really the focus for us this year, Klein said of development, integration and testing.
The target launch date is some time in 2022. A location hasnt been finalized for the mission, but its targeting the South Pole of the Moon for operation during several weeks of Lunar daylight.
Beam me up
So what does a lunar LTE network set up look like? Nokias plans start with equipment thats been optimized and hardened to withstand extreme conditions, from takeoff to landing, to intense radiation once on the surface.
Its all of the commercial network elements scaled down in what essentially becomes an entire LTE network in a box, according to Klein.
You have your radio, your baseband, your core, all your functionality integrated into a single compact unit that will be deployed on the lunar lander, Klein said, along with antennas. He likened it to a small cell with an integrated evolved packet core (ePC).
The user equipment (UE) equivalent is affixed to the rover, also with its own antennas, to establish the link from the lunar lander to the UE on the rover.
The antennas arent beaming down from a typical 100-foot tower height, instead affixed between 3 to 5 meters off the ground. That has a major impact on range, Klein noted, and the project is targeting two scenarios.
One is short-range, sending the rover 300 to 400 meters away from the lander, and a second longer-range target where the rover would be up to 5 kilometers off the lander. Its something Nokia believes is achievable based on experimental validation with its equipment, power levels and height, Klein said.
Along with the LTE system, Nokia provides operation maintenance software that connects back to mission control to handle management, maintenance, configurations, and the remote control of the network itself.
The Moon presents its own unique terrain challenges, but one upside is that you wont find any skyscrapers like you would in the downtown of a major metropolitan area.
The lunar landscape is very different, no obstructions, no buildings, no trees, Klein said. At the same time, you have valleys, and craters and boulders but its generally open terrain so that helps with the range. And electromagnetic waves propagate even without atmosphere.
Searching for a signal?
The purpose of the mission isnt for astronauts to video chat or send GIFs at least not initially.
Space communications typically use proprietary technologies developed by defense or aerospace companies, Klein said, with Wi-Fi used on the International Space Station. And this is different than direct communications from space to Earth using satellites or other technologies.
No cellular technologies are used in space, Klein said. So it would be the first time that cellular comes into play for lunar surface or space communications.    
As an unmanned space mission, the primary goal is to establish surface communications on the Moon  with data links between the lunar lander and a custom-built equivalent of an end user device affixed to the rover. For this project, that primarily involves HD video and data transmission from the rover to the lander, as well as remote control of the rover.
Nokia hopes to deliver on advanced capabilities like throughput, latency, reliability and other features of 4G. In the future, access to information, machine interactions, voice, and video are part of the picture as astronauts enter Lunar, Martian or other space missions.
In the future it will be crewed missions so that astronauts can talk to each other, machines, sensors, devices, and really have all their video, voice applications, biometric applications, telemetry, sensor data collection that they can collect as well as any automation, and robotic control, Klein said.
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Down the line as NASA looks to establish a sustainable presence on the Moon a human element also comes into play and motivates Nokia.
We use cellular technologies every day and astronauts in their personal lives use these capabilities as well, Klein said, and Nokia feels they should also have access to those while performing missions, not just here on Earth. 
Testing, testing
There are four key areas that Nokia needs to prep for to ensure equipment and software is robust enough. 
The first is making sure it survives the launch and landing, Klein explained, with mechanical stressors like shock, vibration and acceleration.
The second is being able to operate in extreme environments, involving temperature ranges, operating in a vacuum and radiation.
Radiation is one of the most unique challenges about space, according to the Klein.
Radiations impact on software is that it could flip bits in code and then all of a sudden your code doesnt work anymore. The question becomes how to guard against and recover from it. And not all hardware components are equally susceptible to radiation, he explained.
Third is reliability, as mentioned earlier.
Here there is just no way you can send somebody to change the equipment, so it has to be absolutely reliable, you have to have redundancy, both on the hardware and software and you have to be able to remotely configure, reboot, and manage your equipment, Klein said.
And fourth is all about size, weight, and power. That means integrating as much as possible into a single form factor, according to Klein, and optimizing power consumption so that dimensions and functions are slimmed down to only what is necessary. But its a balancing act against the third point of reliability and robustness, he noted, with dual-redundancy on the hardware elements.
While radiation might be unique to space, small footprints, energy consumption, and weight are also important for a terrestrial network.
Its not just exciting to put it in space, but we see that wed be pushing the technology and development capabilities that will have applicability in terrestrial environments as well, Klein said. By doing this we will absolutely learn and optimize networks and then bring those lessons back to earth and apply them in our commercial product for enterprise industrial applications.
Picture oil rigs or mines, where remote operation also applies alongside small form factors.
The team is looking forward to a successful mission, to validate performance as well as provide models so that they can design and dimension for future applications potentially on a larger scale in space.
On the personal side for Klein and the team, he said the most exciting aspect is for the technologies Nokia Bell labs has built is pushing them beyond current limits.
Its just a very exciting opportunity to take something as far as you can take it, maybe literally, Klein said.