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-====== Octanis Rover / Balloon: Mission Operations Manual ====== +this page has moved to [[orb:mom|here]]
- +
-**Preface**:​ This document (ORB MOM) contains information about each Rover / Balloon system and every phase of a generic Rover / Balloon mission. The Rover is a Balloon payload, but can be operated separately without regard to the Balloon mission. +
- +
-===== General Description ===== +
-==== Terminology ==== +
-   * Rover: four-wheeled,​ solar-powered robot, capable of autonomous navigation, remote control and telemetry transmission. +
-   * Balloon: assembly consisting of a weather balloon capable of carrying payloads of up to 2kg and a parachute for safe descent. +
-   * Launch: the act of releasing the Balloon to flight. +
-   * Deployment: the act of powering on the rover, uploading command data and letting it navigate to a destination. +
- +
-==== Rover structure ==== +
-==== Balloon structure ==== +
- +
- +
-===== Systems ===== +
-Bracketed words in the title designate the hardware that the system belongs to. +
- +
-==== Electrical Power System (EPS) ==== +
-==== Motor Control (Mainboard) ==== +
-==== Communications (Mainboard) ==== +
-==== Data Logging (Mainboard) ==== +
-==== Watchdog (EPS) ==== +
-==== Guidance, Navigation and Control (Mainboard, Olimex) ==== +
-==== Landing/​Deceleration/​Cutoff System (Balloon) ==== +
-==== Weather Balloon ==== +
- +
-===== Logistics ===== +
-==== Spares ==== +
-==== Tools ==== +
-==== Machines ==== +
-==== Packing ==== +
- +
- +
-===== Operating Limitations ===== +
- +
-===== Normal procedures ===== +
- +
-==== Predeployment (Rover) ==== +
-==== Prelaunch (Balloon) ==== +
-==== Ascent (Balloon) ==== +
-==== Descent (Balloon) ==== +
-==== Postlanding (Balloon) ==== +
-==== Driving (Rover) ==== +
- +
-===== Abort procedures ===== +
-==== Return to base (Rover) ==== +
-==== Systems failures ==== +
- +
-===== Control Documents ===== +
- +
-The following documents must be available to Field Operators and Mission Control on launch/​deployment day for mission execution.  +
-[[octanis_1:​normal_operations_checklist]] +
- +
- +
----- +
- +
- +
-==== Mission Plan ==== +
- +
-The following is the exact mission timeline including checklists that **must be completed without exception**. +
-Timestamps are in UTC and have the following format: DD-MM-YYYY HH:MM +
- +
-**Mission Participants:​** tbd. +
- +
-//No single Octanis member will travel to Antarctica in this mission.//  +
-//Times and dates are subject ​to change. "​x"​ in front of a date means "not confirmed"​. "​✓"​ means confirmed. // +
- +
-  - **======== Deployment ========** +
-      - x[20-10-2015 00:00] Pre-flight ​[[Octanis 1Normal Operations Checklist]] done and problems resolved +
-      - x[21-10-2015 00:00] Pack the rover in the rover box (90cm x 75cm x 43cm, hardcover, padding required) +
-      - x[25-10-2015 00:00] Flight to _ +
-      - x[26-10-2015 00:00] Presentation to _ +
-      - x[07-11-2015 00:00] GO / NO-GO decision from _ +
-      - x[10-11-2015 12:00] Pre-handover [[Octanis 1: Normal Operations Checklist]] ​ done and problems resolved +
-      - x[14-11-2015 12:00] Handover at _ +
-  - **======== Mission ===========** +
-      - x[15-11-2015 00:00] _ commences travel to _ +
-      - x[30-11-2015 00:00] _ reaches _ +
-      - x[01-12-2015 00:00] _ staff executes: [[Guide: Unboxing and Placing the Rover]] +
-      - x[01-12-2015 00:00] Public mission control website goes online. +
-      - x[01-12-2015 00:00] Rover touches Antarctic grounds +
-      - x[01-12-2015 00:00] Rover boots and goes into POST. +
-      - x[01-12-2015 00:00] Rover establishes connection to Iridium network and sends system status. +
-      - x[01-12-2015 00:00] Rover waits for navigation waypoints. +
-      - x[01-12-2015 00:00] Rover receives navigation waypoints, drives autonomously. +
-      - (every 1 minute) Log sensor data, send data via LoRa +
-      - (every 1 hour) Aggregate and send vital status data to Lausanne via Iridium +
-      - (every 1 day) Aggregate and send sensor data to Lausanne via Iridium +
-      - (every waypoint reached) Wait for next waypoint, send ultrasound distance data to Lausanne via Iridium +
-      - x[15-02-2016 00:00] [[Guide: Returning the Rover]] +
-      - x[01-03-2016 00:00] _ staff returns the rover to _ +
-      - x[01-03-2016 00:00] _ staff stores rover +
-      - x[01-08-2016 00:00] _ travels to _ office and receives rover +
-      - x[28-08-2016 00:00] _ completes Pre-flight [[Octanis 1: Normal Operations Checklist]]  +
-      - x[30-08-2016 00:00] Return flight from _ +
-  - **======== Post-Mission ========** +
-      - x[01-09-2016 00:00] Arrival at Hackuarium with rover in rover box. Unbox. +
-      - x[01-09-2016 01:00] Transfer all data from on-board storage. +
-      - x[01-09-2016 01:00] Discussions with data scientists on how to interpret and visualise the data +
-      - x[01-09-2016 00:00] tbd. +
-  +
- +
-==== References ==== +
-   * This manual was inspired by [[https://​drive.google.com/​a/​bitmorse.com/​file/​d/​0Bwa66ZQR4ocHd0JOMHBsd3RqeDQ/​view?​usp=sharing ​Shuttle Crew Operations Manual]] +
- +
- +
- +
- +
- +
-====== Docs ====== +
- +
---- WORKING DOCUMENT PASTED FROM GDOCS VERSION --- +
- +
- +
-Mechanical Design +
-Overview +
-The rover’s design is based on NASA’s nanorover ​ which was a mission to createa small, light-weight and versatile rover to send to asteroids. The rover’s design is simple and yet powerful. +
- +
- +
- +
-The design has been substantially influenced by NASA's MUSES-CN nanorover whose goal was to send small, lightweight rovers to asteroids to explore. Due to the low gravitational field of asteroids, a conventional rover would easily flip over onto its back and be immobile.  +
- +
-The nanorover’s design permits a high freedom of motion and so we apply the same to our rover. If the rover tips over, it can rotate itself to an upright position using its dynamic wheel struts. It can also use the struts to lift a wheel over a small obstacle to keep the body level. The body dimensions are 31cm x 31cm x 15cm.  +
- +
- +
- +
-Wheels +
-The rover has four wheels, each containing a 5V DC motor with a reduction gearbox. Each wheel can turn with up to 3 RPM. A current sensor is used to measure the approximate power consumption of each wheel and is used to notice motor stalls, which can imply that an obstacle was hit but not otherwise detected. +
- +
-The wheels are replaceable and different wheels can be attached just by removing 4 screws. The diameter of a custom wheel should not exceed 15cm to stay within the motors limits. The maximum theoretical inclination achievable is calculated to be 14° based on the wheels maximum torque. +
- +
- +
- +
- +
- +
- +
-Struts +
- +
- +
-Each wheel is attached to a strut (4). Each strut can move in a circle around the common center axis of the rovers body. The center axis is a double shaft. One inside shaft inside the other shaft. The motion of the strut is achieved by driving the center shafts using a custom gearbox. The large herringbone gears (1) are 3D printed and attached to the shafts. They are driven by a gear set on a steel shaft (2) consisting of the herringbone pinion and a COTS worm drive. The worm drive locks the strut. The strut only moves when the motor (3) is powered. The motors powering the struts are attached to optical encoders allowing to locate the struts position. +
- +
- +
- +
-Insulation +
- +
- +
-The rover has a thick layer of insulation surrounding its internal electronics and payload. The insulation consists of layers of BoPET film, styrofoam and PU foam for rigidity. The outer BoPET film layer prevents convection and thus loss of heat. The insulation consists of top (1) and bottom (2) insulation boxes. These boxes are integral to the design as they are also carrying the solar panels and outdoor bay. They can be easily removed to access the internals of the rover for maintenance and payload retrieval. Kapton tape is used when reattaching the boxes after maintenance,​ to prevent air flow between the seams of the two boxes. +
- +
- +
- +
-Base Plate +
-The electronics modules, internal payload and strut gearboxes are all attached to a common base plate (above image, in blue) measuring 25x30cm. This base plate is a rigid material like PMMA or Carbon Fiber Composite. The latter being an expensive option, but saves weight. The base plate has corner positioners where against the insulation boxes are aligned. Thus the insulation boxes attach firmly onto the base plate. +
- +
- +
- +
-Mass +
-The mass of the rover shall not exceed 3kg and is optimally between 2kg and 3kg. The struts and wheels motion strongly depend on the rovers mass. If a higher mass is required, higher power motors must be implemented and higher power demands must be satisfied by the rovers electrical systems.  +
- +
- +
- +
-OBJECTIVES +
-A weather-proof,​ cold-resistant and light-weight rover shall be built that has a simple but solid hardware design. The rover must be able to complete a mission autonomously with assistance where necessary. A mission contains a movement path to be executed which shall be transmitted to the struts and wheels accordingly. The rovers hardware design must be a low cost solution providing robustness, replaceable and reproducible parts. +
- +
- +
- +
- +
-Form +
-Materials +
-For Octanis 1, materials for wheels, struts and gearbox were chosen to withstand temperatures going down to -20°C and to resist solar UV radiation. The material of choice is ABS. Parts requiring high rigidity are made of PLA due to it’s higher Young modulus. Insulating materials were chosen according to NASAs MLI guidelines, specifically our use of metalised polymer film as the outermost layer as radiation barriers. The rovers body is made of a shell of Styrofoam filled with an impact resistant Polyurethane core. +
- +
- +
- +
-Fabrication Methods +
-Custom mechanical parts are created on the lab 3d printer “Prusa i3 Hephestos”. This printer allows the use of ABS and PLA. The time required to print the largest part (wheel) currently is at 12 hours. +
-Other parts like the metal gears are COTS or made from materials that have to be manually manipulated (Styrofoam/​PU body, shafts, baseplate are cut manually. +
- +
- +
- +
-OBJECTIVES +
-The form of the rover must be as robust as possible and at the same time as low cost and light weight as possible. +
- +
- +
- +
- +
-Bays +
-Payload +
-Half of the base plate inside the rover is used for the payload. The payload can be anything designed by the rovers user. The rover provides electrical power and the payload will be exposed to the rovers internal temperature. +
- +
-A payload that will be used for Octanis 1 is described in Section 6.b). +
- +
- +
- +
-Outdoor +
-A bay is situated outside the warm area of the rover containing GPS antenna, Iridium satellite communications module “RockBLOCK”,​ weather sensors and a stereoscopic camera with microphones. A future version will use a common GPS and Iridium antenna. This bay is visible below: +
- +
- +
- +
-OBJECTIVES +
-Each bay must deliver electrical power at 3.3V and 5V to the bay components. +
- +
- +
- +
- +
- +
- +
- +
- +
- +
- +
-Electrical Systems +
-Mainboard +
-By mainboard is meant the central computing unit that interfaces all peripherals of the rover, such as communication modules, sensors and actuators. They are controlled by a MSP432 microcontroller,​ assuring low power consumption. +
-Communication modules +
-Regular data transmission is a mission critical feature of the rover. It is achieved by using the Iridium Short Burst Data (SBD) service with the help of the RockBLOCK Iridium 9602 modem. This modem allows the transmission of data packets of up to 340 bytes outwards and 270 bytes inwards approximately every 20 seconds. Larger data frames can be fragmented and transmitted with multiple packets. The key to this modem and network is that is available everywhere on Earth at any time, something that cannot be said of the GSM network or even amateur radio. Information sent through the Iridium network is automatically sent to a server and uploaded to the project website, where the public can view Octanis’ state and data. +
-For short-range communication from the rover to the base, a RN2483 LoRa transmission module with a theoretical range of 15km  will be used. The standard is very recent and this mission will allow to test its real potential in a cold region with low RF interference. +
-Sensors +
-The onboard sensors are the BNO055 Inertial Measurement Unit to measure the orientation of the rover in space, a BME280 pressure and humidity sensor. +
-Vision +
-Octanis will be able to take snapshots on-demand with a low resolution camera. It is part of an experiment to find out if an image can be efficiently sent via the Iridium network. Additionally we would like to test on-board image processing (e.g. simple feature detection). ​    +
-Navigation +
-There will be two driving modes: discovery and shortest path. Discovery mode will make the rover densely traverse a preprogrammed circular area of a map. Shortest path brings Octanis from waypoint to waypoint using the shortest path. Both methods can be used in combination. Detected obstacles can be stored as landmarks and help build a rough map.  +
-Positioning +
-A GPS module from u-blox will be used for global positioning. Its robustness and precision in a cold but deserted place with no steel construction that may interfere with the GPS signal can so be tested. +
- +
- +
- +
-External weather strip +
-An external sensor module is connected to the mainboard via I2C. It will be used to collect accurate weather data. +
-Sensors +
-The weather strip includes a temperature,​ pressure and humidity sensor, a UV-irradiance sensor and a AS3935 lightning detection circuit which is able to estimate the distance to storms up to 40km away. As a backup, a second Inertial Measurement Unit is included.  +
-Objectives +
-The goal of this external module is to provide highly relevant and accurate weather data which can be used to estimate the future energy production potential. The sensor data can also be used as a complement to local weather stations. +
- +
- +
- +
-EPS (Electrical Power Subsystem) +
-Power regulation +
-The goal of the EPS is to provide a stabilized 3.3 V bus as well as to control the inside temperature of the rover. Solar cells are used as power source. They are directly connected to the 3.3 V power bus through Schottky diodes as protection. To regulate the voltage to 3.3 V, the load on the bus is adapted to the sun irradiation conditions. If too much power is generated, the excess power is either stored in a Li-Ion battery or dissipated as heat using a resistor external to the rover. If more power is required, e.g. during an experiment with high power demands, the additional power is fed by the batteries. +
-The choice of the parallel regulation of the solar cell voltage using a variable load is based on the high efficiency of this approach. No power is lost using DC-DC converters while, compared to a MPPT solution, the hardware remains relatively simple and thus reliable. The same approach was also chosen for the CubeSat currently under development at a few Swiss universities (CubETH) , on whose design the Octanis EPS is based. +
-As the voltage level of the batteries is higher than the 3.3 V bus voltage, a switching step-down converter is used to provide the 3.3 V from the battery. On the other hand, a switching step-up converter is used to generate up to 4.2 V for charging the batteries. +
-While the power dissipation using the external resistor is based on an analog circuit for quick response and reliability,​ the charging command is issued by a low power microcontroller on board. The same microcontroller also measures the temperature of the inside of the rover as well as the batteries and makes sure that the temperature is above 0°C using resistive heaters. +
-The MSP430G2744 microcontroller on the EPS also has the ability to switch of different parts of the rover in case of emergency or to save energy. This includes the power for the mainboard to prevent deep unloading of the batteries during a long phase of darkness. The remaining energy can then be used for the EPS as well as the preheating of the batteries to prepare them for charging. The EPS is designed to provide overall as much as 3A  at a regulated 3.3V voltage to the external modules. +
-The EPS provides 4 protected external switches and 3 additional power outputs on standard HexfetFETs that would normally be reserved to the powering of heaters. It also disposes of 4 analog input pins. +
- +
-Battery & Solar panels +
-A set of two Li-ion 3.7V, 3500mAh Samsung INR18650-35E ​ batteries is used to provide the power autonomy needed by the rover. ​ It provides proper discharge for temperature as low as -20°C and charge temperature as low as 0°C. A temperature control of the battery is provided by the EPS heaters.  +
- +
-The solar panels have a rated output voltage of 3.6V per module and use cells with efficiency above 20% and are used to recharge the rover batteries and power the 3.3V regulated bus. +
- +
- +
- +
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-High Performance Computer +
-A ARM Cortex A7 Dual-core computing device is used for devices with higher computational power requirements like image processing. This board is easier to program (e.g. with Python) but requires orders of magnitude more power. It will be off when not needed. +
- +
- +
-Stereoscopic Imaging +
-A pair of low-resolution USB cameras are attached to the computer, who will have access to audio, video and still images of the cameras. A program will be used to retrieve the images periodically and if possible process a pair of images to create a disparity map. +
-Octanis will be able to take snapshots on-demand. It is part of an experiment to find out if an image can be efficiently sent via the Iridium network.  +
- +
- +
-Experiment Interface +
-A simple interface can be provided to any externally provided experiment through this computer. This interface requires little to no knowledge of embedded systems programming,​ which is the biggest hurdle for experiment designers. A simple pPython script that can run on Debian (ARM) is sufficient. If peripherals are required, these can use the USB, I2C or Serial interfaces of the computer. +
- +
- +
- +
- +
- +
-OBJECTIVES +
-The rover shall carry sensors on board to regularly record and transmit the state of the external and internal environment in a given location. It should provide a standard interface so that scientific instruments can be embedded and exchanged in a simple manner. All data transmitted to and from the rover shall be publicly available on the Internet in real-time. The rover shall have an interface to participate in a wider spread sensor network so that future rovers can work as a swarm. The reliability of its sensors and communication modules shall be investigated. +
- +
- +
- +
- +
- +
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-Payload +
-Baay (interface, power, size) +
- +
-The interface between the rover and the payload is limited to a set of digital I/O pins allowing it to drive the various motors and other actuators present on board (as detailed hereafter). It is basically entirely driven by the Octanis rover main board. +
- +
- +
-Experiment to put in bay: Bubble wrap sample collector +
-+
-The payload to be embedded for the Octanis 1 mission is a liquid sample collector able to melt snow, pump it and keep it sealed inside the rover. The sample collector payload is composed of several elements: +
-an external metallic nozzle with resistive heater +
-5 stepper motor (4phases) with driver +
-5V linear electromechanical actuator to drive the needle +
-needle +
-a peristaltic 5V pump +
-circuitry to drive it  +
-bubble wrap line +
-3D printed support  +
-2 3D printed wheels to roll the bubble wrap line +
- +
-+
-The rover has the capability to drive the buubble wrap sample collector ​   payload and perform the collection by itself, provided the order is given to it.. +
- +
- +
- +
- +
-OBJECTIVES +
-The goal of this part is to explore the possibilities of an extremely low-cost solution of a sample collection mechanism. The grade of reliability and quality of the mechanism shall be investigated +
- +
- +
- +
-Field Scientist Work at Antarctic Base of INAE +
-Hypothesis  +
-On this field experiment, the hypothesis that is proposed is as follows:  +
- +
-A scientific station based in the unmanned environment of Antarctica produces detectable traces of human activities.  +
- +
-This hypothesis will be tested at the Maldonado base (INAE, Antarctic Base of Ecuador), situated on the Greenwich Island, in Antarctica. The criteria for detecting human activities will be bacteria and dead human cells, Total Organic Carbon (TOC), and Organic Matter (OM).     +
- +
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-Experimental procedure +
-The objective of the experiment is to show decreasing of the above-mentioned markers with the distance to the base, that would show that the scientific base e!ectively has an impact on the environment. The experiment will analyze samples collected according to the figure 1, section 4. This map is designed for 2 degrees of freedom, namely distance to the base and distance to the coast. This will allow to discard or estimate input from the ocean to the organic matter and carbon density on the land (see details in section 4). From the collected data, multiple for every sampling point, one can obtain a statistical evolution of the organic activity level, along both degrees of freedom. The sampling strategy, coupled with the statistical analysis, will also allow to discriminate human from possible animal activity. As samples are not taken from running water, there should not be a lot of common living bacteria in the samples. However, the DNA sequencer will tell if dead bacteria or human cells are present in the samples, along with cyanobacteria and other microorganisms (Miteva, 2008). The decreasing of those markers with the distance to the base would show human e!ffect on the environment. After the sequencer test, excitation-emission matrix analysis will be applied, to determine the intensity of the C peak and T peak. Once again, a decreasing in the intensity of those peaks with the distance to the base would denote a decreasing of Total Organic Carbon (TOC), so a human impact (Parlanti and al., 2000). The last step is to determine the UV absorbance at 254 nm with the spectrometer,​ after filtering the sample with a 0.45 microns filter. The resulting intensity can be related to the amount of Organic Matter (OM), which can also denote human activity (Bieroza and al., 2008). +
- +
- +
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-Tool: OceanOptics SpectroPhotometer +
- +
-The Octanis 1 field scientist will have at his disposal for fluorescence analysis purposes a modified S2000 Ocean Optics Spectrometer . It will allow to perform fluorescence spectroscopy on cultivated samples. It will come with a broad range UV source in the form of a compact Deuterium lamp to provide the proper source for fluorescence spectroscopy. +
- +
- +
- +
- +
- +
-Sets of replacement parts +
-Replacement parts for the rover components include: +
-- 2 solar panels +
-- 2 batteries +
-- 2 Power supply PCB’s +
-- 2 mainboard PCB’s +
-- 2 weather strip PCB’s +
-- 4 motors (2 for struts and 2 for wheels) +
-- one part of each gear +
-- one wheel, strut +
-Tools: +
-- various cables, connectors, soldering equipment +
-- basic mechanical tools (screwdrivers,​ tape, etc.) +
- +
- +
- +
-Power required per day +
-The average power consumed daily by the field scientist is related to the power consumption of the computer he will take with him and the spectrometer when he is using it for spectrometry experiments. Overall, the power consumption will never exceed 100W. And over the course of a working day accounting for 8 hours of operation it corresponds to 800Wh as a daily upper margin. +
- +
- +
- +
-Internet required per day +
-The field scientist will need to update mission control about the state of the rover daily, sending out posts on social media platforms, as well as search for relevant scientific information. An estimated sum of 250 MB per day will be required. +
- +
- +
- +
-OBJECTIVES +
-One Field Scientist will travel to Antarctica in Octanis 1 and live at the Base of INAE for 1.5 months, during which experiments will be carried out and the rover tested. +
- +
-  +
-OCTANIS 2 MISSION, 2017-2018,  +
-MAIN TOPIC: “DEPLOYMENT OF ROVER” +
- +
- +
-Introduction +
-The rover of Octanis 1 is a low-cost, low environmental impact rover platform for scientific experiments in cold to extremely cold environments. This rover is small and light-weight enough to be carried on weather balloons.  +
- +
-The Octanis 2 mission will further explore the possibilities of using weather balloons, helicopters or even a drone to deploy the rover to a target destination. Targets could be glaciers or remote locations inaccessible to aircraft that has to land on stable ground. +
- +
- +
- +
-Rover Modifications +
- +
-Measurements taken and experiences made with the rover in Octanis 1 will be studied in detail to make improvements on the rover. The field scientists journal and final report will be analysed rigorously. This is also why it is required to retrieve and send the rover back to Switzerland after the Octanis 1 mission to check the parts for damage and wear. After Octanis 1 the following used elements must be studied carefully:  +
-Wheel set perfomance log (Field Scientists Journal) +
-Strut wear (play on shaft) and warp +
-Strut motors  +
-Wheel motors +
-Battery health +
-Base plate screws and screwholes +
-Base plate inner shaft holder play +
-Strut gearbox wear +
-Payload / Experiment +
- +
- +
- +
- +
- +
-Multiple Rovers +
- +
-At least 2 rovers shall be built to study the performance of two rovers communicating in the field. The communication link can also be used to send learning outcomes to each other: Obstacles, control loop gains, communication timing, self-righting. This way, a swarm of rovers  +
- +
- +
- +
- +
-Aerial Deployment Method +
- +
-«Octanis 2» is all about finding a low-cost aerial deployment method for the rover. We will study various options prior to the mission and propose a viable solution to the collaborating Antarctic base. +
- +
- +
- +
-Helicopter +
-Deploying the rover out of a helicopter which is already on a specific route is a viable and low cost option. The rover could be given to one of the passengers or attached to the transport cord and detached on demand. The rover would swiftly parachute to the ground and begin its mission. +
- +
- +
- +
-Balloon +
- +
-High Altitude Balloons or more commonly known, weather balloons, can be used to bring the rover over its target destination. Helium-filled,​ they typically float up to an altitude of 30km and a trajectory of hundreds of kilometers can be achieved solely by floating with the winds. This is the cheapest method to deploy the rover to Antarctica as it is only required to travel to lower South America, to which commercial flights exist, to launch the rover attached to the balloon. With this benefit comes a higher risk of deployment failure. +
- +
-Once the balloon-rover-configuration have reached their target destination,​ the rover is separated from the balloon and parachutes to the ground. The balloon continues on uncontrolled and will eventually burst or float to the ground after the helium diffuses out. +
- +
- +
- +
-Parachutes +
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-Parachutes are essential for deploying the rover safely from high altitudes. We have devised a method to easily manufacture a correctly functioning parachute according to the model described in White et al . We use the fabric from 3 low cost umbrellas. These already have the desired shape, so we only add cords and cut a calculated hole in the center. The amount of parachutes, cords and size of the hole is topic of research. +
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-Trajectory Simulation for Balloon Flight +
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-When using the balloon flight deployment method, the path of the balloon is difficult to control and thus must rely on rigorous pre-flight simulations with the HYSPLIT simulation software. HYSPLIT was already successfully used in numerous ballooning projects like Piccard and Jones' Breitling-Orbiter 3.  +
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-Retrievability +
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-Due to the Antarctic Treaty the rover must always be retrieved after a completed mission. The rovers retrieval must be done manually either by tether hook (which we will develop) on a helicopter or via a ground vehicle if the location is accessible. The location of the rover is always known (GPS) and recorded (Iridium) so it is simple to find. If the balloon method is chosen, careful simulations must be done to ensure the rover lands in an accessible location. +
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