Here is a concise summary of the provided text:
**Subject:** US Air Force U2 Spy Plane Pilot "Tube Food"
**Key Points:**
1. **Food Description:** Pre-packaged, non-magnetic, aluminum tube meals (approx. 5oz/141g each) designed for U2 spy plane pilots.
2. **Menu Options:** 19 options, including 9 main courses, 5 fruits, and 5 desserts, all mild to prevent digestive issues.
3. **Unique Features:**
* Caffeinated options (e.g., apple pie with 100mg caffeine)
* Special feeding straw for helmet connection
* Three-year shelf life (if stored at 80°F)
* Small heater for warming meals on the plane
4. **Pilot Experience:**
* Pilots choose their favorite menus, eating about 1 tube per hour during 12-hour flights
* Strict diet before flights to prevent in-flight digestive issues
5. **Reviewer's Experience:**
* Tasted caffeinated apple pie and polenta with cheese and bacon, finding them palatable, especially when warmed up
* Noted the tubes' fragility and difficulty in eating with one hand
6. **Production & Rarity:**
* Approximately 28,000 tubes produced annually for around 100 active U2 pilots
* Considered rare and difficult to obtain for non-pilots.
Here are the key facts extracted from the text, numbered and in short sentences, excluding opinions:
**U2 Spy Plane Food Facts**
1. **Weight**: Each food tube weighs approximately 5 oz (141 grams).
2. **Container**: Tubes are made of non-magnetic aluminum.
3. **Production**: About 28,000 tubes are produced annually.
4. **Users**: Around 100 active U2 Spy Plane Pilots use these tubes.
5. **Menu Options**: There are 19 different menu options, including:
* 9 main courses (entrees)
* 5 fruits
* 5 desserts
6. **Caffeinated Items**: Some menu items, like apple pie, contain caffeine (100mg).
7. **Safety Warning**: Tubes should not be used if swollen.
8. **Serialization**: Tubes are dated (e.g., "Tubed March 30th 2021").
9. **Consumption Method**: Food is consumed through a specially threaded straw connected to the pilot's helmet.
10. **Altitude Protection**: Pilots wear special suits to protect against altitudes of 60-70,000 feet.
11. **Dietary Restrictions**: Pilots must follow a specific diet to avoid bowel movements during flights.
12. **Food Design**: Foods are designed to not aggravate or agitate the bowels.
13. **Shelf Life**: Tubes have a 3-year shelf life when stored at 80°F (27°C).
14. **Heating**: Tubes can be heated using a small heater on the spy plane.
15. **Flight Duration**: Pilots eat about 1 tube per hour during 12-hour flight missions.
16. **U2 Spy Plane History**:
* First flight: August 1st, 1955
* Early challenges: 3 fatalities, 3 crashes in 1956
17. **Food Development**: Natick Soldier Research, Development, and Engineering Center develops the tube foods.