StellarXplorers IV Qualifying Round 2 (QR2) Quiz Answer Key

Transcription

1 1. Which of these Electromagnetic radiation bands has the longest wavelength (λ)? [Section 12.1] a. X-Ray b. Visible Light c. Infrared d. Radio 2. How is energy in Electromagnetic (EM) radiation related to frequency? [Section 12.1] a. Lower-frequency waves have the greater energy b. Higher-frequency waves have the greater energy c. It depends on distance from the radiation source d. EM radiation energy is not related to frequency 3. Objects emit EM radiation at different wavelengths depending on their material properties and temperature. For some spacecraft sensors, it is important to know the total energy output of the radiation, using the Stephan-Boltzmann equation. Based on this equation, if we double an object s temperature, the energy output increases times. [Section 12.1] a. 2 b. 4 c. 8 d A workable spacecraft sensor system must first point the sensor at the object it is trying to detect. The spacecraft s total area it can access at any one time based on physical limits of sensors or communication gear is called the. [Section 12.1] a. Swath width b. Field-of-Regard (FOR) c. Field-of-View (FOV) d. Peripheral vision

2 5. A spacecraft sensor system must collect incident radiation and focus it on a detector. The sensor can gather radiation through an aperture either by refraction, reflection, or a combination of the two. How does a radio frequency antenna collect radiation? [Section 12.1] a. Refraction b. Reflection c. A combination of refraction and reflection. 6. A lens collects energy and focuses it on a detector. Modern visual and IR detectors use semi-conductor materials, similar to solar cells. A computer samples the entire array and processes the voltage of each cell and converts the EM radiation into digital signals. What type of technology accomplishes this for high end sensors? [Section 12.1] a. Electromagnetic Film Camera (EMFC) b. Charge-Couple Device (CCD) c. Complementary Metal-Oxide Semiconductor (CMOS) d. IR to Digital Cameras (IRDS) 7. If we multiply the transmitter s power output by its antenna gain, we get an expression that represents the amount of power an isotropic transmitter would have to emit to get the same amount of power on a target. We call this. [Section 13.1] a. Effective Isotropic Radiated Power (EIRP) b. Signal-to-Noise Ratio (S/N) c. Antenna Gain (G) d. Antenna Power ratio (APR) 8. The general name for a device that converts some physical state, such as pressure or temperature, into numbers that computers can manipulate is called a. [Section 13.1] a. Microprocessor b. Data Bus c. Demodulator d. Transducer

3 9. Spacecraft have become flying software, as it is needed to do just about everything on board. We can t over-emphasize the importance of software to a space mission. It controls virtually every action on a spacecraft and the success or failure of a mission can depend on a single line of computer code. In 1969, Mariner-6 launched to Mars and had only 30 lines of code to perform its functions. Forty years later, the Mars Science Lab, Curiosity, required lines of code. [Section 13.1] a. 1 million b. 2 million c. 50 million d. 100 million 10. One of the first tasks of the communication and data-handling subsystem (CDHS) is to convert the real-world analog data into computer-world digital data that it can easily manipulate. The most common way to do this conversion is to sample the analog signal at discrete times and then produce digital values at those times. The Nyquist criterion dictates that to accurately represent an analog signal, we must sample it at least as often as its highest frequency output. [Section 13.1] a. twice b. three times c. five times d. ten times 11. The energy an electric field can transfer to a charge is called. [Section 13.2] a. Voltage b. Current c. Resistance d. Electrical Potential 12. Solar cell efficiency, η, is the percentage of incident solar energy that converts to electrical energy. Silicon solar cells typically have a solar cell efficiency of about. [Section 13.2] a. 15% b. 28% c. 50% d. 75%

4 13. Depth-of-discharge (DOD) is the percentage of total stored energy that is removed from a battery during a discharge period. DOD varies with the altitude of the spacecraft s orbit. Which type of orbit has a DOD of about 50%? [Section 13.2] a. Low Earth Orbit (LEO) b. Medium Earth Orbit (MEO) c. Geostationary Earth Orbit (GEO) d. Lunar Transfer Orbit (LTO) 14. For satellites in low Earth orbit, one important source of heat is called albedo. This results from. [Section 13.3] a. Direct Sunlight b. The infrared energy Earth emits directly, as a result of the Earth s temperature c. Internal heat generated by electrical components or as the result of power production d. Sunlight reflecting off the Earth 15. A passive thermal control system that can meet % of a spacecraft s external thermal-control demands is (are). [Section 13.3] a. Cryogenic coolers b. Multi-Layer Insulation (MLI) c. Heat pipes d. All of the Above 16. For long duration space missions, astronauts need an adequate volume for space to live in. NASA has done extensive analysis on this issue to determine the required volume of living space per astronaut which varies with the mission duration. Based on NASA s analysis, what is the Performance Limit for the Total Habitable Module Volume (living space) per Crewmember for a 6-month space mission? [Section 13.4] a. 5 m 3 per crewmember b. 10 m 3 per crewmember c. 15 m 3 per crewmember d. 19 m 3 per crewmember

5 17. NASA s Water Recovery System (WRS) recycles approximately of water expelled by astronauts from washing hands, bathing, sweat, making coffee, and urinating. [Section 13.4] a. 58% b. 72% c. 85% d. 93% 18. When you apply an axial tension load, the material stretches. This change in length, or deformation, is called. [Section 13.5] a. Stress b. Strain c. Shear d. Fatigue 19. When a load is applied to a material, it will deform (stretch or shrink) a certain amount, depending on load. If the load is removed and the material is 0.2% permanently longer (or shorter), it has reached the. [Section 13.5] a. Proportional Limit b. Yield Point c. Ultimate Tensile Strength d. Failure Point 20. Different models with different levels of testing are used during systems verification. What type of model is used to verify that the design meets requirements? [Section 13.5] a. Proto-Flight Model b. Qualification Model c. Flight Model d. CAD Model