# 5.11. Project: Conditional Launch¶

Complete this project to boost your conditional skills. Don’t worry if you struggle a bit. Struggling (and needing to review) before succeeding is a natural and frequent part of coding. Making mistakes helps you learn.

Note

There is no starter code for this project. However, if your teacher uses a repl.it classroom or a Trinket course, you will submit your work there.

Otherwise, login to your repl.it or Trinket account and start a new project.

## 5.11.1. Spacecraft Data¶

Use the following variables for a spacecraft we want to launch:

Variable Value
`engine_indicator_light` `"red blinking"`
`space_suits_on` `True`
`shuttle_cabin_ready` `True`
`crew_status` `space_suits_on and shuttle_cabin_ready`
`computer_status_code` `200`

## 5.11.2. Part A: PREDICT¶

1. Examine the code below. What will be printed to the console?

Use the value of `engine_indicator_light` assigned above to answer this question.

 ```1 2 3 4 5 6``` ```if (engine_indicator_light == "green"): print("Engines started") elif (engine_indicator_light == "green blinking"): print("Engines preparing to start") else: print("Engines off") ```
2. Do these two code blocks produce the same result?

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```# Code block 1 if (crew_status and computer_status_code == 200 and space_suits_on): print("All systems go!") else: print("WARNING! Not ready.") # Code block 2 if (not crew_status or computer_status_code != 200 or not space_suits_on): print("WARNING. Not ready") else: print("All systems go!") ```

## 5.11.3. Part B: Cabin Safety Checks¶

1. Use an `input` statement to prompt the user to enter the speed of the spacecraft. Store this result in the variable `spacecraft_speed`. Remember to convert the input from the `str` data type to `int` or `float`.
2. Write conditional expressions to satisfy the safety rules below. Use `spacecraft_speed` and the same variables defined at the top of the page.
1. `crew_status`
• If the value is `True`, print `"Crew Ready"`
• Else print `"Crew Not Ready"`
2. `computer_status_code`
• If the value is `200`, print `"Please stand by. Computer is rebooting."`
• Else, if the value is `400`, print `"Success! Computer online."`
• Else print `"ALERT: Computer offline!"`
3. `spacecraft_speed`
• If the speed is `> 17500`, print `"ALERT: Escape velocity reached!"`
• Else, if the speed is `< 8000`, print `"ALERT: Cannot maintain orbit!"`
• Else print `"Stable speed"`
3. Before you move to part C, run your program several times to test your code. Change only ONE variable value at a time to make sure your conditionals print the expected results.
1. Change the value of `space_suits_on` to `False`.
2. Change `computer_status_code` to `400`, then `100`.
3. Enter different values for `spacecraft_speed`. (Tip: `17500` and `8000` should both produce `Stable speed`).

Note

In step 3, you are trying to make your code fail. Testing helps you spot and fix bugs!

## 5.11.4. Part C: Fuel Safety Checks¶

1. Use `if/elif/else` statements to monitor the spacecraft’s fuel status. Order is important when working with conditionals, and the checks below are NOT written in the correct sequence.

Read ALL of the checks before coding and decide on the best order for the statements.

1. If `fuel_level` is above 20000 AND `engine_temperature` is at or below 2500, print `"Full tank. Engines good."`
2. If `fuel_level` is above 10000 AND `engine_temperature` is at or below 2500, print `"Fuel level above 50%.  Engines good."`
3. If `fuel_level` is above 5000 AND `engine_temperature` is at or below 2500, print `"Fuel level above 25%. Engines good."`
4. If `fuel_level` is at or below 5000 OR `engine_temperature` is above 2500, print `"Check fuel level. Engines running hot."`
5. If `fuel_level` is below 1000 OR `engine_temperature` is above 3500 OR `engine_indicator_light` is red blinking, print ```"ENGINE FAILURE IMMINENT!"```
6. Otherwise, print `"Fuel and engine status pending..."`

### 5.11.4.1. Test Your Fuel Status Code¶

Run your code several times to make sure it prints the correct phrase for each set of conditions. The table below gives you some practice values as well as the expected output.

fuel_level engine_temperature engine_indicator_light Result
Any Any `red blinking` `ENGINE FAILURE IMMINENT!`
21000 1200 NOT `red blinking` `Full tank. Engines good.`
900 Any Any `ENGINE FAILURE IMMINENT!`
5000 1200 NOT `red blinking` `Check fuel level. Engines running hot.`
12000 2600 NOT `red blinking` `Check fuel level. Engines running hot.`
18000 2500 NOT `red blinking` `Fuel level above 50%. Engines good.`

## 5.11.5. A Final Bit of Fun!¶

The spacecraft should only launch if the fuel tank is full and the engine check is OK. However, let’s establish an override command to ignore any warnings and send the ship into space anyway!

1. Create the variable `command_override`, and set it to be `True` or `False`.

If `command_override` is `False`, then the shuttle should only launch if the fuel and engine check are OK.

If `command_override` is `True`, then the shuttle will launch regardless of the fuel and engine status.

2. Code the following `if/else` check:

If `fuel_level` is above 20000 AND `engine_indicator_light` is NOT red blinking OR `command_override` is true print ```"Cleared to launch!"```

Else print `"Launch scrubbed!"`