December 5, 2023

The Moon: Going Where No Satnav Has Gone Before

The test version of a special satellite navigation receiver has been provided for combination testing on SSTLs Lunar Pathfinder spacecraft.” It will be flown aboard the Lunar Pathfinder objective into orbit around the Moon, from where it will perform the furthest satellite navigation placing fix ever made, at more than 400,000 km away to a precision of less than 100 m. “There is a long heritage of lunar laser ranging, going back to the Apollo missions, and the retroreflector we are utilizing is an evolution from NASAs Lunar Reconnaissance Orbiter. To get rid of that limitation, the second phase, the core of the Moonlight system, will see dedicated lunar navigation satellites and lunar surface area beacons providing additional ranging sources and extended protection.” Our Moonlight effort proposes the preliminary placing of 3 to 4 satellites in lunar orbit, using at least five consecutive hours of service in any 24 hours, focused on the lunar south pole where many of the objectives are at first prepared,” includes Javier.

European Engineering & & Consultancy, EECL, in the UK was appointed the job of turning SpacePNTs design into fully-tested hardware, additionally creating the crucial low noise amplifier that sifts through noise to improve functional signals.
” The amplifier is a high-end customized diplexer covering the double frequency satnav bands, hand-tuned utilizing the very best possible components and incorporating heat sink innovation to further lower unwanted sound,” says Ben Kieniewicz, ECCL founder.
” Along with contributing to other design aspects, we also developed, evaluated, and provided the receiver to SSTL, utilizing our space-qualified cleanroom assembly and test area.”
ESAs Moonlight effort includes expanding satnav protection and interaction links to the Moon. The first stage includes showing using existing satnav signals around the Moon. This will be accomplished with the Lunar Pathfinder satellite in 2024. The primary challenge will be overcoming the restricted geometry of satnav signals all coming from the same part of the sky, along with the low signal power. To overcome that restriction, the 2nd stage, the core of the Moonlight system, will see dedicated lunar navigation satellites and lunar surface beacons offering extra ranging sources and extended coverage. Credit: ESA-K Oldenburg
Lunar Pathfinder will be prepared for launch at the end of 2024, providing near side, farside, orbit, and polar services to missions releasing in the coming years, laying the foundations for a constellation of combined telecommunications and navigation satellites around the Moon.
” Our Moonlight initiative proposes the initial placement of 3 to 4 satellites in lunar orbit, using at least five successive hours of service in any 24 hours, concentrated on the lunar south pole where most of the objectives are initially prepared,” adds Javier. “Our system is conceived to be expandable and the concept is to progressively expand the constellation, and probably to also include surface beacons on the Moon. This will allow complete coverage throughout the lunar surface area, greater availability, and excellent accuracies– an excellent chance for Europe.”
About Moonlight
Moonlight is the Agencys effort to create an enduring link with the Moon by establishing lunar telecommunications and navigation services, assisting enable future exploration.
ESA will propose the creation of a constellation of telecoms and navigation satellites in lunar orbit for approval by ESA Member States ministers at the Agencys Council at Ministerial Level at completion of 2022.

Surrey Satellite Technology Ltd (SSTL), Goonhilly Earth Station (GES) and the European Space Agency (ESA) have actually signed a partnership arrangement for Commercial Lunar Mission Support Services at the Space Symposium in Colorado Springs today. This ingenious business partnership for exploration aims to establish a European lunar telecoms and navigation infrastructure, consisting of the delivery of payloads and nanosats to lunar orbit. Credit: SSTL
The washing-machine-sized Lunar Pathfinder is being built as an industrial objective by Surrey Satellite Technology Ltd, SSTL, in the UK. ESA is funding visitor payloads for it consisting of the 1.4 kg NaviMoon receiver that will be accommodated beside the spacecrafts primary X-band transmitter that links it with Earth.
” Receiving physical hardware for a mission is constantly great,” remarks Lily Forward, SSTL system engineer. “This engineering model receiver will be integrated into our FlatSat Test Bed variation of the mission to evaluate all our systems communicate and interact effectively, ahead of getting the flight model receiver and antenna later this year.”
Lunar Pathfinder will communicate communications from orbital and surface missions. Credit: SSTL
This will be SSTLs very first full-fledged mission beyond Earth, she adds: “Laying the structures for numerous scientific objectives that will come after it, Lunar Pathfinder is a communications relay satellite, planned to serve possessions on both the nearside and farside, orbiting in an elliptical lunar frozen orbit for extended protection over the South Pole– a specific focus for future exploration. Throughout regular periods we will orient the spacecraft towards Earth to test out the NaviMoon receiver.”
Satnav position fixes from the receiver will be compared with conventional radio varying carried out using Lunar Pathfinders X-band transmitter along with laser ranging performed utilizing a retroreflector contributed by NASA and established by the KBR business.
ESAs laser ranging station in Tenerife aims its green laser to the sky. Credit: ESA
” This will be the very first time these 3 varying techniques will be utilized together in deep space” explains ESA navigation engineer Pietro Giordano. “There is a long heritage of lunar laser varying, going back to the Apollo objectives, and the retroreflector we are using is a development from NASAs Lunar Reconnaissance Orbiter. The mix of all varying strategies will enhance the orbit evaluation even more, potentially beyond what radio varying can achieve.
” In concept this might imply that future missions might navigate themselves to the Moon autonomously using satellite navigation signals alone with no assistance from the ground.”
Finding ultra-faint satnav signals
The satnav signals utilized down here on Earth are already vanishingly faint, equivalent to a single set of vehicle headlights shining all across Europe. By the time these signals reach the Moon after they have actually crossed distances of more than 20 times further still, attenuating through space like ripples from a stone splashed in water.
Navigation satellites– such as Europes Galileo, the United States GPS, Russias Glonass or their Japanese, Indian and chinese counterparts– intend their antennas directly at Earth. Any satellite orbiting above these constellation can just hope to identify signals from over Earths far side, however the bulk are obstructed by the planet. For a position fix, a satnav receiver needs a minimum of 4 satellites to be visible, however this is most of the time not possible if based solely on front-facing signals.
” Adding to the difficulty, the satnav constellations are not designed to transmit up into area however keep their antennas facing Earth,” adds Pietro. “So we are reliant on much weaker side lobe signals, like light spilling from the sides of a flashlight. To be able to utilize these signals we turned to an expert in space-based satellite navigation, whose signal-processing methods have actually shown the magic active ingredient.”
Testing the NaviMoon receiver and Low Noise Amplifier engineering models at SSTL ahead of combination screening. The flight models of the receiver and amplifier will be delivered later in 2022. Credit: SSTL
SpacePNT, based in Switzerland, managed the NaviMoon receiver design. “We started dealing with the concept of lunar-distance satnav positioning back in 2013 as something of a scientific challenge.” discusses Cyril Botteron, heading the business.
” The mix of Galileo double frequency signals with those of the existing GPS satellites is what began to make it feasible. Although, along with the extreme sensitivity that is demanded, the other big problem is that from the Moon all the satnav satellites remain in the exact same narrow geometry of sky around Earth, occasionally turning out of view.”
Lunar navigation satellites will ultimately help direct Moon landings. This image reveals the cargo setup of the European Large Logistics Lander, delivering supplies and even rovers or robots to the Moons surface for astronauts as part of NASAs Artemis program. Credit: ESA/ATG-Medialab
The service that SpacePNT developed leverages majority a century of lunar exploration. The company set up a vibrant software application design of all the forces acting on the satellite into the receiver, consisting of the gravitational impacts of the Moon, Earth, Sun and worlds along with the very slight push from sunshine itself– solar radiation pressure– together with aspects such as clock error and the radio signal instructions.
Cyril explains: “As we experience an offered velocity the receiver can evaluate it is most probably at one particular point in its orbit. Usually a satnav receiver needs signals from four satellites to fix its position, but with this approach even less than four signals is still adequate to obtain helpful details, constraining the design to minimize any mistake drift.”

Artists impression of Surrey Satellite Technology Ltd (SSTL)s Lunar Pathfinder satellite that will offer interactions services around the Moon. Credit: SSTL
The test variation of an unique satellite navigation receiver has actually been delivered for combination screening on the Lunar Pathfinder spacecraft. The NaviMoon satnav receiver is created to perform the farthest ever placing repair from Earth, utilizing signals countless times fainter than those used by our autos or mobile phones.
” This engineering model of our NaviMoon receiver is the really first piece of hardware to be produced in the context of ESAs Moonlight effort, to develop dedicated telecoms and navigation services for the Moon,” explains Javier Ventura-Traveset, Head of ESAs Navigation Science Office and managing all ESA lunar navigation activities.
The test variation of a distinct satellite navigation receiver has been provided for integration screening on SSTLs Lunar Pathfinder spacecraft. The NaviMoon satnav receiver is designed to perform the furthest ever positioning repair from Earth, employing signals that will be millions of times fainter than those utilized by our smartphones or automobiles.
” It will be flown aboard the Lunar Pathfinder mission into orbit around the Moon, from where it will carry out the furthest satellite navigation placing fix ever made, at more than 400,000 km away to an accuracy of less than 100 m. This represents an extraordinary engineering difficulty, because at such a range the faint Galileo and GPS signals it makes use of will be barely appreciable from background sound. This presentation will suggest a real modification of paradigm for lunar orbiting navigation.”