The European Space Agency (ESA) is working on a new system to enable easy docking between two spacecraft. maxon developed two special drive systems for this purpose.
Even though it’s been done many times before, the docking manoeuvre between two objects in space is always a delicate and potentially dangerous procedure. The speed is extremely high (about 28,000 km/h in case of the ISS), and corrections are difficult. For example, when the two objects are about to meet, manoeuvring thrusters can no longer be used, since their exhaust plumes can cause damage. To prevent harm, cargo transporters are caught by a robotic arm installed in the International Space Station (ISS) and berthed manually. Manned spacecraft on the other hand dock directly in a computer-controlled process.
This type of docking manoeuvre is going to become easier and safer in the future, so the European Space Agency (ESA) has commissioned its industry partners to design a new docking system called IBDM (International Berthing and Docking Mechanism). This conforms to the International Docking System Standard (IDSS), a standard on which the leading space agencies worldwide have agreed. The system will therefore be compatible with the ISS and most other spacecraft. The mechanism’s first missions will be with the Dream Chaser, a craft that looks like a compact version of the Space Shuttle and will soon perform cargo flights to the ISS. The craft is being developed by the Sierra Nevada Corporation.
Docking energy is absorbed
The IBDM is an androgynous coupling system. This means that the connector is identical on both sides. It consist of a hard inner ring (Hard Capture System) and a soft outer ring (Soft Capture System) that has six degrees of freedom and force sensors. The outer ring first absorbs the docking energy. Then the final airtight connection is made and secured by mechanical hooks which pull the two spacecraft tightly together.
SENER is in charge of developing and installing the Hard Capture System. The company is currently working on the qualification model, which is due for testing in 2020. “Then the IBDM needs to be used as quickly as possible on a supply flight for the ISS,” says SENER’s Gabriel Ybarra. One of the next steps would be to use it in NASA’s Lunar Space Station, which is planned to go into orbit around the moon and could serve as a launch point for manned missions to Mars in the future.
Dual systems for maximum safety
This is a challenging project for the engineers at SENER: “We first needed to fully understand all the requirements set by ESA and NASA and figure out how to fulfill these requirements. And especially with regard to safety, because the docking mechanism can also cope with manned flights.” As well as being lightweight and delivering the required torque, the electrical drives that are used must also be extremely reliable. This is why SENER has been working with the drive specialist maxon for several years.
maxon’s engineers have developed two drives for SENER that can be used to execute a huge variety of functions. This first drive consists of two brushless EC-4pole motors and a GPX UP gearhead. Twelve of these actuators power the locking hooks in the IBDM docking mechanism. The second drive combines a flat motor with a planetary gearhead. It is used in eleven places, to manage the plug-in connections and the retaining eyes, as well as other ancillary functions.
As the IBDM docking mechanism is a flight-critical application, redundant drive systems are required. The backup must function even if the primary drive fails. This is often solved by means of a backup motor that can take over in an emergency. This is the approach used for the locking hook actuator. For the other drive system however, the maxon engineers found a different, unconventional solution: an additional stator is used instead of an extra motor. The flat motor therefore has two stators and hence two windings, each of which is capable of independently driving the rotor – an ingenuous solution, which guarantees safety while saving space.
Gabriel Ybarra praises the collaboration with maxon: “The team understands our requirements and is very quick with design modifications.” Moreover, both partners have a passion for mechatronic systems. “It feels great to be involved in the entire cycle, from design to production and testing. This makes it extremely interesting. And when the system moves for the first time, it’s like watching your children take their first steps.”
For more information contact maxon motor Australia tel. +61 2 9457 7477.
maxon has been selected to supply the optical filter changer system for what will soon be the largest wide field telescope in the world. The project, involving five French research laboratories, requires motors and controllers capable of working to an accuracy of 1/10th of a millimetre.
With its 8.4-meter mirror and 3.2 gigapixel camera (making it the biggest digital camera in the world), the Large Synoptic Survey Telescope (LSST) is a project that is defined by superlatives. Its mission? To extend the boundaries of the visible universe but also to tirelessly survey and map the universe for the next 10 years from the observatory on the summit of Cerro Pachón in Chile.
The LSST: the product of expertise from all over the world
To achieve its mission, the Large Synoptic Survey Telescope will photograph the entire sky several times each week, allowing it to catalogue changes and measure the movement of the celestial bodies. Its astronomical surveys will contribute to studies designed to elucidate the structure and evolution of the Solar System and Milky Way. The findings will also be applied in various research projects dedicated to unlocking the mysteries of dark matter and dark energy.
Coordinated by the USA, the project has a budget of some USD 675 million (approximately EUR 600 million). Almost twenty countries will contribute to analysis of results with inputs from research laboratories from all around the world. Alongside the United States and Chile, France is playing an active part in the construction of the telescope through the French National Institute of Nuclear and Particle Physics (IN2P3).
Precision engineering in the service of astronomy
The telescope is installed on the 2,680 meter-high summit of Cerro Pachón, a site chosen for its very low levels of atmospheric and luminous interference. It is housed in a dome that is 30 meters in diameter and 17 meters high. The dome is fully motorised, so that the telescope can be rotated to successively point in all possible directions.
The telescope itself consists of three main elements. The first of these is the mount with which the telescope is precisely positioned in preparation for observations. Then there is the optical element, which is made up of three curved, aspherical mirrors, the largest of which has a diameter of more than 8 meters. Finally, there is the digital camera, which is one of the project’s centrepieces.
This camera is built around a 3.2 billion pixel digital sensor that is chilled to -100°C. This is sensitive to a particularly broad range of light, from near ultraviolet to near infrared, so that photometric measurements can be carried out across the entire spectrum. Finally, the camera incorporates a system of optic filters that enable users to select the fraction of the light spectrum that they wish to observe.
Fast-action optical filter changer
All astronomical survey telescopes incorporate a filter changer but most of the systems currently in use are too slow to meet the ambitious performance requirements of the LSST, demanding changeover 15 times faster than that of other instruments of a similar size.
A team of five French laboratories therefore collaborated in the development of a robotic system capable of placing a new filter over the imaging camera in only a few minutes. In meeting this challenge, the team had to deal with major technical constraints, starting with the integration of the automatic filter changer, as all of its components had to be housed in the body of the camera. And there it must remain perfectly stable, even in the event of a strong earthquake.
The team designed a device capable of handling the extremely costly filters – each with a diameter of 75 cm and weighing almost 40 kg – with an accuracy of a tenth of a millimetre. The centre piece of the device is a carousel that can be loaded with up to five filters and present one of them for use in less than 20 seconds. In addition, there is an automatic mechanism for loading/unloading a filter onto the camera and another mechanism for loading filters within the camera. Together, these three elements go to make up the automatic filter changer.
Compactness, reliability, support
It is in this context that the French National Institute of Nuclear and Particle Physics (LPNHE) sought expert support from MDP – maxon France. The online configurator and associated technical documentation posted on the maxon website served as a starting point for identifying the initial components suitable for integration in the system.
In the course of further exchanges, the suitability of solutions from MDP – maxon France was validated, and the use of the same supplier for the motor/controller combination meant that there would be no compatibility issues. For example, the carousel and the automatic filter changer use maxon EC40/GP42 and RE40/GP52C drive motors along with an EPOS2 70/10 modular digital positioning controller.
Among the various criteria adopted by the teams working on the LSST were the compactness of the components, motors, gearheads and controllers – an essential factor as these had to integrated in the heart of the camera – combined with complete reliability. Indeed, the filter changer must be able to function continuously, with maintenance limited to a period of 2 weeks every 2 years when operation of the telescope is interrupted for re-aluminisation of its mirrors.
The demanding nature of the work carried out on the optical filter changer reflects the ambition of the project and gives some idea of the extent of collaboration required among the various stakeholders in the LSST. For its part, maxon is delighted that its online configurator, its motors, and its electronic systems have contributed to the successful realisation of such a technical and scientific challenge!.
For more information contact maxon motor Australia tel. +61 2 9457 7477.
maxon DC motors are currently on Mars, helping collect vital information on the Red Planet.
On November 26, 2018 NASA’s InSight rover touched down on Mars. maxon DC motors went straight into action to unfold the two solar panels, securing the energy supply that operates the all-important probe. There are two main instruments onboard InSight, a seismometer to measure potential quakes on Mars and a heat sensor designed to drill down five meters into the ground. The sensor was developed by German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). Its rod digs into the hard soil using a hammer mechanism, driven by a DCX motor from maxon. The rate of boring down strongly depends on the composition of the soil, which hasn’t been ideal, the rod hit an obstruction in the very first hammering cycle. However, the engineers at DLR are confident these complexities can be overcome and that the sensor will reach the projected depth.
To efficiently drive the penetrometer into the ground, the DC motor needed to withstand forces in excess of 400 g – and more than 100,000 times. It took a number of variations and failed tests to find the right solution. The result is a standard DCX 22 motor, greatly modified with additional welding rings, bearing welds and specially shortened brushes. The GP 22 HD gearhead, on the other hand, only needed Mars-specific lubrication.
InSight’s mission is to carry out several measurements over a period of two years and provide insights into Mars and the formation of Earth. The mission is being conducted by the Jet Propulsion Laboratory (JPL) for NASA.
For more information on DC motors and gearheads that withstand exceptionally harsh environments, strong vibrations and extreme temperatures contact maxon motor Australia tel. +61 2 9457 7477.
Landing on Mars on 26 November 2018 was NASA’s InSight mission to Mars. The InSight probe is used in the analysis of the formation of rocky planets, involving driving a measuring probe five meters deep into the ground. maxon engineers pulled out all the stops to make their motor fit for the job.
The robotic InSight probe landed on Mars on November 26. If all goes according to plan, the stationary lander will proceed to carry out various measurements over a period of two years and provide important insights into Mars and the formation of Earth. The mission is being conducted by the Jet Propulsion Laboratory (JPL) for NASA.
Motor rams penetrometer 5 meters deep into the ground
DC motors from the Obwalden-based drive specialist maxon motor are also on board. A compact motor-gearhead combination with a diameter of 22 millimeters is used in the HP3 probe developed by the German Aerospace Center (DLR). It is designed to determine the temperature profile of the planet. Specifically, the maxon drive is located in a rod-shaped penetrometer, nicknamed “the Mole” by the developers. This penetrometer is autonomously driven five meters into the ground. To achieve this, the motor tensions a spring with each revolution. The spring then releases with great force, executing a powerful downward punch. In this way, the “Mole” gradually burrows downwards – over a period of several weeks, pulling along a cable that is equipped with sensors to help the researchers determine the thermal state of the interior of Mars and draw conclusions about its origin. Since Mars is a rocky planet like Earth, the scientific results may also help gain a better understanding of our own planet.
Special solution for more than 400 g
Mars is not a very friendly environment for technology. Nonetheless, more than a hundred maxon drives have already proven their worth on the Red Planet. The current InSight mission, however, posed additional challenges for the Swiss engineers. To efficiently drive the penetrometer into the ground, the DC motor needs to withstand forces in excess of 400 g – and more than 100,000 times. It took a number of variations and failed tests to find the right solution. The result is a standard DCX 22 motor, greatly modified with additional welding rings, bearing welds and specially shortened brushes. The utilised GP 22 HD gearhead, on the other hand, only needed Mars-specific lubrication.
Say hello to an old acquaintance
The InSight probe is powered by two solar panels for the duration of its mission. To save costs, JPL repurposed designs from the successful Phoenix mission, using a maxon DC motor developed some time ago to extend the solar panels. This type of motor, an RE 25, has ensured that NASA’s Opportunity rover has been active on Mars for more than 14 years (even if it is currently in deep sleep due to a sandstorm). Thus, two generations of maxon drives come together in the InSight robot probe to jointly contribute to the mission’s success.
For more information please contact maxon motor Australia tel. + 61 2 9457 7477.
Almost one year to this day 15 years ago, NASA Rover Opportunity embarked on its journey to Mars.
NASA Engineers have been trying to reach the Opportunity Rover in recent weeks, however due to a heavy and persistent sandstorm they haven’t been able to make contact. It’s assumed the batteries have fallen below 24V causing the machine to enter into standby mode. It needs sunlight to recharge the batteries to “wake up” the computer and resume communications.
Opportunity’s six wheels are driven by maxon DC motors. There are 35 drive systems with diameters of 20mm and 25mm for the rover. The maxon motors in the wheels, for example, did more than 78 million revolutions each, under extreme environmental conditions and temperature fluctuations from -120 to +25ºC. The practicalities and knowledge from this successful project are being transferred across developments of new motors that will soon fly to Mars on forthcoming missions by NASA and ESA. “Opportunity has braved many minor and major sand storms over the years and has always managed to recover its energy. We have no doubt that our motors will also run without trouble afterwards,” says maxon CEO Eugen Elmiger.
For more information on DC motors to suit harsh environment applications please contact maxon motor tel. +61 2 9457 7477.
Maxon motor have supplied DC motor and gearhead combinations for NASA’s fifth Rover mission – the 2020 Mars Rover.
NASA’s Jet Propulsion Laboratory is building a Rover that will travel to Mars in 2020. The purpose of this operation is to collect dozens of soil samples, seal them and leave them on Mars for future pick-up. Nine brushless (flat) pancake DC motors and gearhead combinations from maxon’s standard range – that have been heavily customised to withstand the harsh conditions on Mars – are used in the sample handling arm, specifically developed for this mission.
The sample handling arm moves the containers from station to station within the sampling system. Additional DC motors are also in the Rover and assist with obtaining the samples and sealing the containers. Maxon’s brushless DC motors and gearheads need to survive the powerful entry, descent and landing sequence as well as the harsh daily conditions on Mars with sandstorms and temperatures ranging from -130 to +70ºC.
From the outside, the Mars 2020 rover looks similar to its precursor Curiosity, that is still operating on Mars. The 2020 mission will have several new instruments on board to deliver unique new data. A key objective will be to search Mars for bio-signatures. Another instrument on board will test whether it’s possible to generate oxygen from the atmosphere for possible future human visits. However, the most significant innovation is the ability to take rock samples in several locations and prepare them for return to Earth.
For assistance on customised DC motor technology for applications in harsh environments please contact maxon motor Australia tel. +61 2 9457 7477.
Brushless motors from maxon motor are again being used by NASA for the Mars 2020 rover.
For critical tasks you need the best quality. The Jet Propulsion Laboratory have selected nine brushless flat motors from maxon motor for the rover which they intend will take soil samples and seal them in containers for future transport to Earth. Various motion applications are performed. Sample tube holding, the robotic arm, container handling, sample gathering and container sealing. 32mm diameter and 20mm diameter flat brushless motors have been combined with heavy duty 22mm planetary gearheads and modified specifically for the Mars mission in close collaboration with JPL for the difficult conditions experienced with descent, landing, sandstorms and the -130 to +70 degree temperatures.
For information on DC motors and gearheads used in applications operating in harsh environments please contact maxon motor Australia tel. +61 2 9457 7477.
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Maxon motor built models of the Mars Rovers Sojourner, Opportunity and ExoMars for a Space exhibit at the Swiss Museum of Transport.
The Swiss Museum of Transport in Lucerne is updating their Space exhibition. With maxon motor trainee help, the exhibit features complete 1:1 scale models of the Mars Rovers Sojourner, Opportunity and ExoMars. The models have moving parts including the camera head and drilling units. Visitors at the Swiss Museum can get an up-close look at the outer space technology and even take a selfie with a Mars Rover.
Maxon motor manufactured 35 DC motors and drives in the real Opportunity Rover that survived 10+ years on Mars. As well, at their headquarters in Sachseln, maxon assembled parts of the ExoMars Rover including modules that drive the vehicle and are responsible for the steering. The ExoMars is due for launch in 2020.
For similar stories to this you can view maxon’s driven magazine online, or for information on outer space technology please contact maxon motor Australia on Tel. +61 2 9457 7477.
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