Lunar Escape: Development of Astronaut Recovery Rover Program

Transcription

1 Lunar Escape: Development of Astronaut Recovery Rover Program Nicholas Wade-Mayhue, Dan Janke, Kyle Kilgore, Mohammed Alzohay, Samad Qureshi Colorado School of Mines Advisor: Dr. Knecht March 30, 2009 Abstract As NASA looks into the future of lunar exploration, the requirement of an astronaut recovery program must be recognized. As no other programs are currently in existence to fulfill this need, we must acknowledge the necessity of astronaut safeguards against possible volatile environments. It is with this need that the Sensory Moon Astronaut Recovery and Transport (SMART) rover has been established. The SMART rover will be physically attached to the existing Lunar Electric Rover (LER) or can be docked at the nearest Lunar Outpost. This innovative capability will trace and recover any lost/injured astronaut when remotely activated via a panic button placed on space suits which, when pressed, will establish a communication link with NASA headquarters, other astronauts on the lunar surface, as well as initiate the rover s recovery program. 1. Introduction The safety of America s astronauts are rapidly becoming a larger issue due to the fact that NASA prepares to return people to the moon in It is for this reason that we have proposed our designs of an astronaut recovery system. The focus of this structure is in the recovery of injured astronauts who are a considerable distance away from the Lunar Electric Rover (LER) or the lunar outpost. The best way we found to do this is with the Sensory Moon Astronaut Recovery and Transport (SMART) rover. The intent of the Lunar Escape project is that the Sensory Moon Astronaut Recovery and Transport (SMART) rover will be physically attached to the existing Lunar Electric Rover (LER). It can be activated by a means of remote control that the astronauts will have placed on their suits. The technology utilized for this remote control will be quite similar to that of the Life-Alert system currently in place. Once activated, the SMART rover will then follow sensors that are placed in the regolith to the lost/stranded/injured astronauts, retrieve them, and traverse back to the nearest LER or lunar outpost. It is important that the SMART rover integrates each of the other subsystems in order for the astronaut recovery system to be successful. 2. Subsystem Design The SMART rover system itself consists of 4 major components: a panic button to summon the robotic rover, sensory beacons to guide the rover to the astronaut, life support and first aid kits on the rover to aid the astronaut, and the SMART rover itself SMART Rover Launch Button Technical Specifications The SMART rover launch button is based on the same principle as the LifeAlert system. As such, it is relatively small and not cumbersome to the astronaut. The launch button is approximately 2 ¼ inches in diameter, and ¾ inch wide. Please see Figure 1 for dimensions and close-up. Figure 1. SMART rover launch button The launch button is made from Torlon polyamideimide (PAI). This is a very high strength plastic which has the highest strength and stiffness of any thermoplastic up to 275 C (525 F). Not only is this plastic strong, it also has excellent resistance to wear, chemicals, and is ideally suited for severe service environments, such as space exploration. Since the material is a high grade plastic, this price is relatively inexpensive, compared to that of a highgrade metal. Quotes for molding and preparing this launch switch have been around $25. Given that this 1

2 launch switch is made of plastic, it is also quite light. We believe that this switch will weigh no more than ½ pound Assembly and Operation The launch button is connected to the Communications Carrier Assembly in the astronaut s helmet. The button is located on the display and control module on the front of the suit for easy access. Power is provided to the button through the display and control module from the Primary Life Support System (PLSS). Please figure 2 for launch button specifics. ease from greater distances and would be more cost effective. The range provided when signal switching should be approximately meters moving from the 5 meters provided with the product. The cost at the moment for changing this is unknown, but the beacons each cost $ The beacon s purpose is not to emit the light, but is focused on sending an electronic signal. It would use a 5W max bulb with a max voltage of 250W. Switching signals would provide a robotic sensor with a greater range. Figure 3. Sensory beacon Assembly and Operation Figure 2. Launch button connection When the astronaut engages the launch button, it will signal an alert to the SMART rover, invoking the rover s recovery program. The recovery program initiates the SMART rover which follows sensors placed in the lunar regolith to the astronaut. Upon pushing this launch button, communication will be automatic to all other astronauts on the lunar surface, as well as with NASA Headquarters Sensory Beacons Technical Specifications We are basing our design of the beacon tracking as similar to that of Telemecanique s product, XVDLS Mini Beacons. See figure 3 for product identification. These beacons are cost efficient, light, and portable. This specific product will have 1.75-inch diameter. The materials this beacon is made out of will allow the beacon to operate in space without any reactions. Because of the limited range of the beacon signal, it is recommended that the astronaut carry multiple beacons with them on excursions. One solution may be to alter the beacon signals to a more effective one; a free-space optics/radio frequency on each of these beacons would suffice. It would allow the rescue rover to track each beacon with The beacon allows the robot locate the injured astronaut once activated. The rover will follow the same path as the sensors are placed, allowing for decreased chance for the rover to run into craters or encounter other problems while navigating. The astronauts must drop the beacon at least every 20 meters or the chances of the rover failing to find the next sensor will certainly increase on navigation Life Support/First Aid Technical Specifications The immediate concern for a fallen astronaut is to make sure they remain able to breathe. It is for this reason that it is of utmost importance that air supply is on the rescue rover. The design for this is as simple as adding an additional air backpack strapped to the car. The pack that will be strapped to the rover is the same as the one that is strapped to the backs of the astronauts so there will be no need for any additional hoses or equipment. Extra hoses will be on the rover as well in the event that there is a malfunction in one of the astronaut s existing hoses. The next concern deals with different scenarios. Because of the difficulties faced while on the lunar surface, the SMART rover will have the capability to swap out medical kits. One such kit would carry radiation blankets for thermal flare-ups, another would carry splints. It is with the rover s ability to adhere to any situation that 2

3 makes this design practical. All components of this subsystem are lightweight. The SMART rover is a fully customizable system, which allows all the aforementioned items to be added/removed The SMART Rover Technical Specifications The SMART rover s design is based roughly off of the design of the Apollo lunar roving vehicle. There is room on the rover for two astronauts, one injured astronaut on a detachable stretcher on the front of the rover and a second healthy astronaut standing up on the steering platform behind him. Each individual wheel has its own 1hp electric motor, mounted relatively close to the wheel and protected from dust by aluminum casing. These motors are powered by high-efficiency lithium ion batteries mounted in the rear of the rover. The wheels themselves are highly protected by dust guards, as this was a major problem on the Apollo moon missions. The steering mechanism, such as the one on the Apollo lunar roving vehicle, is a straightforward joystick which is responsible for not only steering but also acceleration and braking. See Figure 4 for steering mechanism. The rear of the rover has a remote controlled hookup to the LER. The hookup releases upon the push of the SMART rover launch button by the astronaut. A winch is mounted above the stretcher on the steering console. This winch is capable of attaching to the stretcher, allowing for the injured astronaut, on the stretcher, to be pulled onto the SMART rover. A ramp stowed under the body of the chassis is able to be pulled out to assist in this process. See Figure 5 for SMART rover description. Figure 5. SMART rover description The dimensions of the SMART rover are important. The smallest the chassis can be to maintain effectiveness is 102 inches, allowing 73.5 inches for the stretcher and 18 inches for the standing astronaut. The front of the chassis (with the stretcher) may need to be extended to account for taller astronauts. The base of the chassis is 4 feet wide, with a three-foot stretcher that is centered on the top. The wheel axels are ten inches below the top of the chassis and extend eight inches out in both directions. The wheels themselves are 7 inches wide and 32 inches in diameter, which should provide adequate clearance for rough moon terrain. The dust guards extend 230 degrees around. The steering console rises up three feet from the chassis and has the same width. Please see Figure 6 for wheel description. Figure 4. Steering Mechanism 3

4 Figure 7. Frame Specifications Figure 6. Wheel Description Much of the rover can be built using 2in x.25in square aluminum 1060 tubing. This material is available for $14.00 a foot at 2.05lb/ft. Estimating the need of approximately 75 feet, the whole of the chassis and steering column will cost $ and weigh only lbs. The wheels are the same as those used on the Apollo lunar roving vehicle which were lightweight yet durable and made of an aluminum frame and zinc-coated, woven steel strands. Including the aluminum dust guard, each wheel weighs no more than 150 lbs, and costs around $1, Each motor is a DC series wound 1hp electric motor with capabilities of 10,000rpm. A similar steering motor may also be necessary. These motors cost approximately $1, and weigh about 60lbs. Any common stretcher may be used and average costs and weights are no more than $ and 15lbs. An adequate stretcher winch capable of 1500lb costs $95.00 and weighs 100lbs. This brings the total cost of the materials, with an extra $2, figured in for electronics, to $12, Figuring at least 200 hours for labor at $20/hr, the total cost is $16,945.00, though NASA labor costs and transportation costs are admittedly unknown. The total weight, with an extra 100lbs figured in for electronics, comes to lbs, with potential for weight savings in the frame and wheels. See Figure 7 for frame specifications Assembly and Operation The assembly of the SMART rover is the same as any moving vehicle. All aluminum components should be welded together to ensure the strongest vehicle. Major points of emphasis are that the winch should be bolted to the steering console behind and above the stretcher to serve its purpose best. The hookup to the LER should be welded to the rear of the SMART rover so that when detached it does not need to reverse; it will only need to detach, then drive forward. 3. Conclusion With a new era of space and lunar exploration arising, our team was given the chance to expand on NASA s astronaut recovery program. Because the scope of this project was so innovative, our team had the ability to devise new ways for astronaut recovery that has never been looked into before. It is the goal of the team to devise and propose a plan with the intention of creating and expanding on existing NASA astronaut recovery practices. Our goal has led to our development of the very adaptable SMART rover. With the SMART rover s automatic recovery program and the ability to modify to any situation, astronauts can feel safe while traversing the unknown. 4

5 4. References [1] Solvay Advanced Polymers, (2009). More Endurance from our High Strength Plastics [online]. URL: bybrand/torlon/0,, ,00.htm [accessed 29 March 2009] [2] Telemecanique, (2009). Illuminated Beacons and Indicating Banks [online]. URL: s/19/ html [accessed 29 March 2009] [3] Oberg, James. "Space exploration." World Book Online Reference Center World Book, Inc