After you stabilized Spurgeon, team leader Melissa Lewis decides Artemis 13 needs to go home before anything else happens. Just as she gives the order to rotate boosters in order to send the ship home the crew feels the spacecraft rock violently and warning lights start going off everywhere. The command ship starts to lose all of its power. After a quick investigation, it turns out that the circuit that controls all of the key systems is currently drawing too much current from the battery. You are in constant communication with Austin about the issues you are encountering and a bright but intense intern proposes a risky but possibly brilliant solution. They want to take two batteries from the mostly dead Command Ship and use them to help power the Artemis. In addition to the 230 V main battery, they say they need 140 V (Vbat1) from the Command Ship battery and only 5 V (Vbat2) from the backup battery to get them home. From the ship manual you find the following resistances for different components that need to be powered in order to get you all home:
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The Artemis 13 is on its way home but before they complete their final landing sequence the team need to launch a top-secret deep space probe. However, power supply for the whole ship is running critically low, so you are now only running the ECS to maintain oxygen in the command module. You have to somehow power up the probe to complete your mission. You no longer have communications with Austin.
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* Gauge Lights: RGL=100Ω
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* Navigation System: RNS=700Ω
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* Steering/Direction Control: RSDC=950Ω
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* Engine Cooling System: RECS=500Ω
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* Air Filter: RAF=300Ω
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* Waste Management System: RWMS=425Ω
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{{ 184_notes:project7a.png?550 }}
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You notice as you begin powering up the probe (which operates on its own reserve power system) that although the navigational controls have been primed, there are several components that are not responding to testing. It appears that the circuit switch control board got fried during the test jump, as a result, you now need to create a new circuit that will allow you to provide different amounts of energy to the propulsion system's module on the probe.
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Will this circuit work without drawing any more than the 0.35 A from the main battery?
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That propulsion system consists of the primary burners and the cooling system, which have a total resistance of 65 Ω.
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The primary burners require a short burst of 200 J to power-up.
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The cooling system requires a short burst 300 J to power-up.
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==== Project 7B: Power Is Everything ====
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You need to be able to deliver different amounts of power to this module; however, you are growing concerned that the power supply the probe has access to of 100 V may not be sufficient to power these probe systems. You manage to find some additional batteries onboard (three 10 V batteries from the supply room) to use if you need them.
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The Artemis 13 was able to turn on its boosters and move the craft towards home. Since power is in short supply, several non-vital systems were shut down. However, to successfully go through the landing sequence they MUST turn on the guidance computer system (GCS), Environmental Control Systems (ECS), Communications Relay (CR), the warm-up control for the primers for the parachutes (PP), and the Command Control Module (CCM), as well as a floodlight (FL) in the cockpit using only the main battery (230 V).
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You also have several 0.125F capacitors and resistors (1 Ω, 5 Ω, 10 Ω, 50 Ω, 100 Ω) on hand.
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You also have access to multiple switches that can be used to open and close parts of the circuit you are designing.
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Your team on the ground has been working in a simulator to figure out how to turn on each of the systems in various orders, but keeps running into problems. If the total current from the main battery on board exceeds 0.35 A, the battery will die and the Artemis will lose power before it can return safely to Earth. Your flight expert has sent over the most recent steps he has tried and the data they collected for each step.
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There is a breaker in the circuit that is a failsafe and will trip if the current exceeds 2 A. You also know that there are delicate circuit elements in the primary burners and the cooling system, so the propulsion system should not be connected to any power supplies when charging capacitors.
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- Turn on only the CR, which seems to work properly and only draws 0.242 A from the battery.
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You should provide a circuit diagram of your design that helps you explain to your crew that the current in the circuit is safe and that you are going to be able to supply the needed power to the systems when the time comes to launch the probe. As a check for yourself, you should make sure that the voltage in the circuit adds up to the correct amount as to not suffer any voltage shortages.
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- Then turn on the PP, which decreases the current from the battery. The CR seems to barely be functioning so you conclude that it is running at it's minimum power of 18.35 W.
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- Next they turned everything off, and switched on only the PP and the FL. Immediately the warning light goes off in the simulator because the current from the battery is way too high at 1.48 A and the flood light has burnt out because the power in the bulb was 264.6 W (exceeding their maximum power rating of 120 W).
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<WRAP info>
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- You decide to start over and turn everything off again. You turn on the CS, ECS, and CCM - which seems to be perfectly alright. The current from the battery is maintaining at a nice and safe 0.188 A. Since this combination works well, you grab the hand-dandy multimeter and find that the CS, ECS, and CCM have the same current but that the CS is using the most power (17.7 W) and the ECS is using the least (10.6 W).
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=== Learning Goals ===
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- Just to try one more thing, they turn everything off and then turn on only the PP and the CS. You find that even though they have the same voltage the current going through these elements are different.
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* Understand how capacitors charge and discharge
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* Use the relationship between capacitance and energy
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* Understand what happens when capacitors are in parallel or in series
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* Understand how capacitors and resistors combine in a complex circuit
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</WRAP>
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==== Project 8B: Detecting magnetic fields ====
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{{183_projects:magnetic.jpg?600}}
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An experimental magnetic field detector has been constructed outside of the town of Lakeview. Although the purpose of the detector is largely unknown to the townsfolk of Lakeview you and your team have been recruited to develop a magnetic field detector that is able to detect hawkions. Hawkions are like muons, but are slow-moving and have long lifetimes. They are a newly discovered top secret particle that experiments on the Artemis 13 have indicated should exist. You have a somewhat constructed model, in which the hawkions follow a straight line trajectory, but it looks like there's some pieces of code that the team wasn't sure what to do with. You will need to select a few locations to model the magnetic field due to the hawkions and produce arrows that represent the hawkion's magnetic field. Best hurry, the government needs more information about the hawkions particle before it is too late.
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<code python>
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## Scene setup
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scene.background = color.white
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Mission Control wants to try to turn everything on at once as it is currently configured. They are running out of time and need to get something to the Artemis. Will the current configuration of these elements in a circuit allow the Artemis 13 to get home safely??