Wireless Reliability on the Moon
NASA pursues tried-and-true 4G LTE wireless network capabilities for the lunar surface.
With astronauts planning to return to the moon in 2024 for the first time since 1972, NASA will leverage commercial technology to mount a wireless communications network there. The capability will support the exchange of data and communications of autonomous systems, robots and astronauts. The fourth-generation long-term evolution of mobile communications, commonly known as 4G LTE, will provide the network’s reliability for NASA to conduct its lunar activity. And this dependability is key in such an austere space environment, says Niki Werkheiser, director of Technology Maturation at NASA’s Space Technology Mission Directorate.
“We believe that the 4G LTE technology can be used for reliable, proximity, wireless communications in space. And so, this will ultimately provide us with reliability and resilience in our high-capacity communications network,” she says. “Having that communications network in place is one of the keys to supporting a sustainable human presence on the lunar surface, and eventually on Mars.”
Fully in the wheelhouse of advancing technologies for future space missions, Werkheiser leads NASA’s Game Changing Development effort. In addition, she leads the space agency’s Lunar Surface Innovation Initiative that guides establishment of new capabilities needed for lunar surface exploration. In these positions, the director manages an annual portfolio of $200 million.
NASA plans on using the lunar communication solutions in various ways, she states. “We can communicate between our lunar landers or rovers, eventually with our habitat, when astronauts are on an EVA [extravehicular activity, or spacewalk], and with power stations,” Werkheiser says. Using the 4G LTE network, the space agency also is looking to harness high-quality video streaming and real-time navigation capabilities—such as teleoperating or controlling rover vehicles.
Currently, the fifth generation (5G) network is being deployed on Earth by telecommunications providers, and the military is adopting the network in the United States. The industry also is taking initial steps for the next generation of wireless after that, or 6G, (see page 20). Even so, NASA is initially starting with demonstration of 4G LTE technologies for the moon.
“LTE is attractive to us for multiple reasons,” the director notes. “It’s a proven commercial technology. It has a large ecosystem of technology and component suppliers. It is also deployed worldwide, so that makes it an attractive technology for us to adapt for space applications. It’s a robust and scalable technology with bandwidth and power-efficient technologies that have been proven. For those reasons, we really feel like LTE is poised to provide a cost-effective solution for our space, and in particular, our early lunar communication capabilities.”
To help mature the relevant technologies needed for application of space and lunar communications, NASA’s first 4G LTE technology demonstration—planned for late 2022—involves 4G LTE technology from Nokia Corp. of America. The space agency appreciated the company’s experience with end-to-end terrestrial systems and emergency operations, as well as the systems that Nokia developed for automation, data collection and reliable communications, Werkheiser explains.
“I think it is going to be a very exciting and impactful first demonstration,” she states. “For us, these public-private partnerships are important because we really can leverage the commercial technologies that have been developed terrestrially and adapt those for space application.”
The technology for the first demonstration will include an LTE base station and antennas, and perhaps most importantly for NASA, highly reliable control software. “Often, the software and automation capabilities are afterthoughts, because the focus is on the hardware development, but Nokia’s proposal fully addressed all of the developmental aspects, ” Werkheiser shares. “They have a very reliable control software system. It will actually be the first of its kind of ultra-compact and low-power, space-hardened end-to-end LTE solution.”
To get the demonstration equipment to the moon for testing, the directorate is working with another NASA office, the Science Mission Directorate, to rely on its commercial lunar payload services (CLPS). CLPS has an ecosystem of different launch providers that NASA selected as eligible to bid on taking un-crewed cargo to the Moon. And Nokia has partnered with Intuitive Machines, one of the CLPS providers for the mission, she notes.
“It is really important that we’re able to use CLPS and these early robotic missions to test key technology even before human presence on the moon, in order to buy down the risk and increase the technology readiness levels (TRL) for what we consider to be core capabilities like communications,” Werkheiser states.
The Intuitive Machines’ robotic lander will deploy the equipment once on the moon’s surface, at which point the 4G LTE network will self-configure. “Achieving that level of autonomy is often one of our challenges,” the director notes. “The system must be reliable enough to dependably configure and operate with no humans in the loop, so the ability to self-configure is a key advancement. The LTE base station will mount on the lander, while the other LTE equipment will be mounted on a small rover or hopper. The power station or any other payloads are being deployed outside the lander. It’s a really clever design that is ideal for this first demonstration.”
The space agency aims to increase the TRL of the space-based 4G LTE communications technology to “flight proven” from successful mission operations. “For this particular demonstration, we will focus on advancing the TRL of the hardware and the software from a [TRL] 7 to 9, which is really exciting, because this will enable full mission scale for human missions,” she emphasizes.
It helps that Nokia had already been on a path for how to operate a wireless network in space, having had a prior endeavor with a private space company in Germany, Werkheiser mentions. The company had already performed electromagnetic acceleration, shock vibration testing, experimentation in thermal vacuum chambers and radiation testing.
“By already having performed much of the testing required to survive launch and operate in the challenging environment of space, Nokia not only increased the TRL significantly, but enabled us to accelerate the schedule for the flight demonstration on the lunar surface,” she confirms.
NASA’s testing will now focus on the operational aspects, as well as on interface testing with Intuitive Machines and their launch vehicle. “The environment itself that it has to operate in, and the level of the autonomy that we need, is really the trick,” Werkheiser says. “It has to be designed to be robust enough to survive the dynamics that are present during launch and the considerable vibration, and it has to be space hardened in order to really operate in extreme conditions. And the moon is pretty extreme. Lunar noon can go up to 100 degrees Celsius, and then lunar night can dip down to minus 180 degrees Celsius.”
In addition, in the permanently shadowed regions of the moon—where NASA suggests there may be water and where their robots will explore—temperatures can go down to minus 240 degrees Celsius. “So, being able to operate successfully and reliably in that environment is a critical aspect,” the director stresses.
And while the planned 4G LTE network is meant to support initial activity on the moon in the next few years, NASA is taking a long-term view regarding space-based communications capability development, Werkheiser shares.
“The Artemis program is laying the foundation for a sustained long-term presence on the lunar surface,” she says. “The moon itself is kind of a testbed for us. As our lunar presence and capabilities grow, we will use what we have learned on the moon for our next giant leap, which, of course, is the human exploration of Mars. Everything that we are learning and testing out on the moon will apply there as well.”
“In our Space Technology Mission Directorate, our motto is really technology driving exploration,” the director continues. “We are developing and demonstrating this critical and transformative technology to enable robotic and human flights on the moon, establish that sustainable lunar presence and then move forward to Mars.”