Proposal
Back to TopOverview and Goals
Why the Moon?
For as long as men were able to gaze at the stars, men have looked to the Moon and wondered about its mystery. In this day and age, with the leaps and bounds in technology, it is no wonder that the thoughts of man have once again wandered back to the beacon in the sky.
With a gravitational potential easily one sixth of the Earth's, the medical industry envisions the possibility of new ways of life on the moon for those with debilitating diseases; with its lack of light-pollution, the astronomers and space explorers alike envision it as a waystation among the stars. To restate an old phrase, ˇ§the possibilities are endlessˇ¨, and with the aid of Google and the X Prize Foundation, the world is about to see how far the limits of technology can be pushed as the race for space opens up its latest chapter in innovation.
What are the goals for the team in this research and design challenge?
Because of the Google Lunar X Prize Competition's focus on the concept and design, a unique opportunity had been created for both the industry savvy expert as well as the innovative, young, high school student.
We've envisioned a moon rover that would not only fulfill the competition's requirements of completing a soft landing, roaming for at least 500 meters, and sending out the first Mooncast, but also the and extra bonus missions such as surviving a Lunar night and capturing images of the Apollo 11 mission's remnants.
Our design will be highly researched with key components explored and explained. We hope to create a practical and resilient rover ˇV one that would be mid-range in the pricing category since the cheapest materials available are understood to be unable to withstand the test of time, whereas the top of the line, cutting-edge technological advances are not fool-proof as well as highly expensive. Yet, we are not without our own sci-fi-inspired ideas of the upcoming space-age, which will become evident in our overall design.
Back to TopDescription
Why has your team chosen such a particular shape for the rover?
Our rover aims, in every aspect in its design, to be different from a standard moon rover, although we do not fully forsake the roots of functional rovers. This is most apparent in the external depiction of our rover; we want our rover to exemplify the futuristic, revolutionary aims of the X Prize Competition, and as such we have chosen a more aesthetically pleasing design than the norm. Whereas most robots are generally cluttered and complicated, our rover is sleek and rounded in design, with most of the parts hidden from view. It is a rounded, egg-like machine with an uncomplicated look kind of like a standard automobile, with components that retract and expand when necessary.
This has functional benefits as well. The smoothed shape will aid slightly in navigation, removing any dangerous edges from the robot, so that there is no catching of corners on jagged rocks or the like. The retractable elements of the rover will shield sensitive machinery, such as the laser transmitter, camera, and solar panels, from radiation or any dust that our rover might kick up.
What features make up the rover?
And regarding radiation, gold has been proven to be a good shielding material against the solar radiation which will be an issue on the moon [1]. As such, a protective covering of gold paint on the outside of the rover will work well for ensuring the integrity of many of the internal components. Some of the most sensitive components might be covered in an additional layer of gold covering, as a precaution.
Our rover is constructed using carbon nanotubes, a futuristic material that is "50 times stronger than steel, with outstanding thermal and electrical conductivity" [2]. As for the internal components themselves, they consist of, among other things, a laser data transmitter, a power system consisting of solar panels and lithium-ion batteries.
Back to TopInternal Components
Where will the internal components be located and why are they located there?
The main lithium batteries will be in the center-bottom part of the rover, so that it can easily be wired to all parts that require electricity. The heating system uses Radioisotope Heating Units, which work through the decay of a low-grade isotope, to warm up the rover; the spherical design would be able to regulate temperatures more efficiently, so the system would be at maximum output.
Solar panels would be placed in the back of the rover (essentially, the trunk). In standby mode, where the robot is only focused on charging, the solar panels would extend out through the back and unfold so they could capture sunlight.
The wiring inside the rover will be mainly comprised of copper/silver wiring, supplying the rover with energy all throughout.
The panoramic camera will be placed somewhere on the upper section of the rover, so that when it extends out the top, it can see in a 360 degree view. Below the camera will be the main computer and its hard drive, where it stores its information and sends the data to the laser communication unit directly above it, which can beam the Mooncast back to earth.
The computer, due to its navigation ability, will be able to store the Moon's surroundings as the camera records and draw an internal map which will be sent it back to earth so that we (the humans), will be able to get more knowledge of the moon's surface.
Motors will be placed both on the front side and on the back side, where it too will supply movement to the gears and thus the treads.
Back to TopLanding
Where will the rover land?
When dealing with the moon's variable surface, we designed our rover with maximum versatility in case of mishaps. Yet, we still took into account the fact that the starting point plays a crucial role in the success of any mission. To limit the presence of dangers such as uncrossable obstructions as well as large pitfalls and craters of which our rover may not be able to climb out of, we decided, early on, to land in one of the moon's various marias since they provide the smoothest terrain on the moon [3]. By following a trail of previously manned space missions[4], which we trust had locations that were thoroughly scouted for safety reasons, we arrived on the conclusion that the best location to land would be within Mare Tranquillitatis[5] which was also the location of the famous Apollo 11 mission.
Another possible landing location would be within the boundries of Mare Imbrium[6]. Due to its vast size and distinctive shape, it is easily located, thus a fall-back location if a precision landing will not be possible.
How will the rover land in its designated landing spot?
In order to launch the rover into space, NASA's method of direct ascent[7][8] would be used to make an efficient use of fuel with scaled down Nova Rocket thrusters that detach once the rover has escaped the Earth's gravitational pull. The rover itself will be encased within a smaller capsule with small rocket thrusters to navigate the rover into position as well as dampen the impact of landing. After much debate, we decided that the capsule would be constructed from carbon nanotubing[9] which was selected for its durability against high temperatures as well as its light weight.
The landing will be a soft landing guided by a gradual decent using the thrusters to decelerate. As an added protection for the rover, it will be secured and cushioned with a styrofoam-type substance to protect its hardware. Once landed, the rover will boot-up and stall for two minutes as the dust around the capsule settles before exiting the capsule for exploration.
Back to TopMotor System
Being mobile is an important part of the lives of both humans and rovers. Even if they have all the energy in the world, without funneling that energy into something, it goes to waste. Naturally, a lot of that energy goes into moving around, traveling the land, in search of more sights and resources. In the lunar rover's case, it's important to move in order to accomplish many goals. This includes charting more of the moon, keeping up with the movement of the sun as much as possible, and, of course, being able to accomplish the goal of moving 500 meters. To achieve this, we need a motor that's power efficient, has a minimal mass, simple design, and few of components in order for it to be affordable.
What kind of motor will be used to power the rover?
Our solution? We plan on using an electric motor to power the triangular treads on our rover. An electric motor, naturally, transforms electric energy from the lithium-ion batteries into mechanical energy, giving the rover the ability to move. We selected the geared BEI Sensors motor (part DXP15-07), a motor with a peak torque of 14.3 oz/in and a mass of 42.5g, to drive the rover, and we plan on using four of these, two on each side to produce enough torque. Basically, the part consists of a DC (direct current) motor connected to a shaft and gearbox, which gets the gears running and will transfer the energy into the treads of the rover. There is no separate steering motor to turn the rover; rather, the motors can be run independently on one side or the other to turn the rover.
What shape are the treads and why?
We chose to use oversize triangular treads, made of open-mesh piano wire with titanium cleats (like the actual NASA rover) for our rover, for a specific reason [10] It's very important that the rover does not get stuck or otherwise disabled, since it's not a simple matter to push the rover out of a rut, or flip it back over, when it's 300,000 km away.
Treads, especially triangular ones, spread the weight more equally, helping the rover in avoiding the danger of sinking into the moon or getting stuck in craters or rough, rigid areas.
Back to TopNavigation
It's one thing to get to the moon; and it's another thing to get around the moon. Getting the moon rover to navigate itself successfully will be one of the biggest challenges, and one of the most important things to the mission. If the rover cannot move, it cannot complete the mission and cannot achieve anything on the moon.
How will the rover navigate itself while on the Moon?
The best offense for navigating the moon is, as they say, a good defense, and we aim to accomplish that with our rover by building it so that it can navigate more safely and smoothly. First off, the long wheelbase and length of our robot will help by lowering its center of gravity, making it tougher to tip over. And the slightly triangular treads that we move on will allow the robot's weight to be distributed evenly, so that the rover can remain balanced and not sink into the moon's surface or get stuck on rocks.
What type of equipment is needed to help the rover with its navigation?
A lot of the power behind our rover navigating the moon, though, will be our array of cameras and sensors that will help the rover dynamically map and chart the moon. Our rover will be equipped with a set of cameras similar to the ones being used on NASA's current Mars rover, with a set of cameras in the front of the rover for "stereo imaging" of the terrain ahead [11][12]. Stereo imaging is an advanced technology that produces images that computer programs (such as the one shown in NASA's Mars rover or demonstrated in the DARPA Grand Challenge) can analyze and produce a 3D map from.
This 3D map will be used by the rover to determine a safe path to travel on, free of craters and other dangers. Small rocks and inclines should not be a problem, as the large treads and strong motor will be able to traverse these freely.
Back to TopPower
Energy is one of the most important things to mankind. Without energy, no living thing can function. Likewise, the issue of powering the moon rover is vital, as without power, it is essentially an oversized doorstop. It is essential to all space missions that the vehicle being used for transport be able to sustain itself for a long period of time, as it is not a simple matter of plugging it into an outlet on the moon to recharge it.
What is the rover's power source while on the Moon?
The moon rover needs a steady, lasting power source, and as such solar power is not feasible for the rover's main power source. Even if we do land the rover on the sunny side of the moon as planned, it will not be possible to stay there forever, as the robot will not be able to keep pace with the sun by any means.
Battery power is a more feasible option for our main power source, being reliable, yet still able to produce the required amount of voltage and current. Lithium-ion batteries are the cutting edge of technology in terms of powering spacecraft, able to provide up to 160 watt-hours of energy per kilogram [13][14]. We believe that with our estimates for power usage (see table below), 40 kg of these batteries will be enough to power our rover comfortably for the minimum 2 weeks that we plan for it to function on the moon.
Still, battery power is an admittedly limited resource, as it is nonrenewable on its own, which is why we suggest having an alternate / backup power source of solar power. It may not be enough to power the rover on its own, and it may not be available all the time, but it will work excellently for the first week or two of our journey, when the rover is on the sunny side of the moon, and the 100 Watts generated by the two MSX-50 solar panels will greatly cut into the strain on the batteries [15]. Additionally, we plan on devoting large periods of time on the moon - perhaps about half the time - to solely generating solar power, in order to maximize battery life.
Back to TopCommunication
The issue of communication between rover and earth is one of the most essential to the mission; with the mission requiring that we transmit a high-definition 'mooncast' back to earth containing streaming video and panoramic images, a strong transmitter connection will be required in order to successfully fill this requirement.
How will the rover communicate with Earth? What type of equipment will it use?
Traditionally moon missions have employed radio communication to talk with the Earth, but with advances in technology, a new and exciting form of transfering data has been innovated, utilizing laser links. These laser links, such as the ones engineered by Oerlikon, are faster and more efficient than radio waves, with both a shorter wavelength and a faster wavespeed meaning quicker transmission of data - potentially over 170 MB a second (and at the bare minimum, 210 kilobytes a second), which should far exceed the 256 kilobytes a second bitrate required in the guidelines [16][17] Additionally, since laser transmission is generally more accurate than radio waves, the transmitter is light on power, requiring only between 40 and 80 watts.
The transmitter is compact as well, requiring about a third of a cubic meter (.6 x .65 x .8 m) and thus can be easily mounted on top of our rover for direct rover-earth communication. An issue that requires consideration for this way of transmission, however, is that the laser beam, being precise, requires a relatively direct line of sight. Luckily, since we are landing in Mare Tranquillitatis, located on the near side of the Moon, the rover will be facing the Earth at all times, which means that we will be able to contact the Earth at least for 8 hours every day [18][19].
Currently we are planning to use the communication link solely in one direction, as our rover lacks any form of receptor for incoming data transmission. This is in the interests of both saving space, weight, and power, and as a challenge to ourselves, to create a rover that can autonomously traverse the Moon without needing human control. As for the data we will be transmitting back, the 'mooncast' will consist of the majority of it, although we plan to also send back 3D maps of the moon, that our rover has created (see Navigation section), as a tool for future moon exploration missions.
Back to TopCamera
The moon's surface is characterized by mountainous highlands and craters, those of which can be detrimental to the success of any lunar mission.
How will the rover's camera system function?
To overcome the Moon's ruggedness, our robot has modes to prevent difficulty and streamline function; one of which is Explorer Mode. During this mode (which is active, of course, when the robot is exploring the surface), a slit located at the apex of the curvature of the rover discloses a panoramic camera. This camera serves as the main source of capturing high quality photographs. With the camera's capability of rotating 360 degrees, it is able to view its surroundings in all directions and record high-definition video [20][21]
Prior to the panoramic camera, two other cameras on the frontal exterior of the rover are utilized for charting lunar surfaces using a concept called stereo imaging [22]. This records its own surroundings and feeds the images back to the mainframe computer, creating an image with perceptive depth and 3D perspective. This allows the computer to make its own detailed map of the moon as it explores in order to avoid falling into holes/craters, or making the same mistakes again. Also, photographic activity will only be taking place on luminous areas, so there will be no need to take pictures on the shadows of the moon.
Back to TopModels
Labeled Illustration
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Top Skeletal View
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Side Skeletal View
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Front Skeletal View
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Isometric Skeletal View
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eDrawing File
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MilkShape Source File (same as eDrawing file)
Requires the free MilkShape Program to view
Back to TopAnimation
Motor System Demonstration #1 (requires Adobe Flash Player)
Back to TopBibliography
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- < http://en.wikipedia.org/wiki/Image:Moon_names.jpg >
- Oerlikon PDF - spa_06
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