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Questions and Answers
What is one of the major disadvantages of modern rockets mentioned?
Why must parts and devices for spacecraft be space-qualified?
Which characteristic is essential for satellites due to the limitations of modern rockets?
What is the consequence of the complexity and high costs of modern rockets on spacecraft design?
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What percentage of the total travel cost is accounted for by travel insurance during the hypothetical trip?
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What is one of the primary physical principles underlying rocket engine theory?
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Which principle states that an object with no net force will remain at a constant velocity?
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Which type of engine requires a consideration of Electromagnetism in its theory?
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What is a significant drawback associated with rocket launchers for customers?
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What do stage rockets primarily allow for in space missions?
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Which is not a constituent part of the required physics for understanding rocket engines?
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According to Newton's third principle, what happens when one body applies a force on another?
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What does the term 'figures of merit' refer to in rocket sciences?
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What principle states that a system conserves linear momentum if no net external force acts upon it?
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What does the term 𝑝𝑝⃗ represent in the equation 𝑝𝑝⃗i = 𝑝𝑝⃗f?
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Why was a retraction published by the New York Times regarding Goddard's work?
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What is the total impulse 𝐼𝐼 defined as?
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If a person on a wagon throws a brick horizontally, what must happen to the momentum of the system?
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What assumption is made regarding the bricks in the embedded problem?
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What was the main function of rocket engines as discussed in the content?
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What is not a requirement for the conservation of linear momentum?
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What is the primary goal of conditioned optimization in multi-stage launchers?
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Which method is utilized for solving the logarithmic expression in multi-stage launcher optimization?
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Which of the following statements is EMPIRICALLY true regarding stages in multi-stage launchers?
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What does the optimal payload mass-ratio for each stage depend on?
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What does the $C_3$ parameter represent in launcher performance assessment?
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Which launcher has a payload to Low Earth Orbit (LEO) capacity of 3800 kg?
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What happens to the mass of each subsequent stage in a multi-stage launcher?
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Which of the following is NOT a critical aspect when evaluating orbit injection accuracy?
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What is one advantage of vertical take-off/vertical landing systems in SSTO design?
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Which of the following is a disadvantage of electromagnetic launchers?
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What must the cost of modern launchers for small satellites be to compete effectively with piggyback launches?
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What characteristic is NOT listed as a property of interest for modern launchers for small satellites?
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Which of the following describes the use of wings in vertical take-off systems?
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What is one potential advantage of horizontal landing systems?
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What is a primary feature of the Delta-Clipper X?
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Which of the following types of launchers are suited for launching nano and picosatellites?
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Study Notes
Rocket Engines and Launchers
- Rocket engines are the current method for space travel.
- Rocket engines have several disadvantages.
- Most launchers are not reusable except for Falcon 9 and its derivatives.
- Launchers are expensive.
- Rocket performances are modest.
- Rockets are relatively unreliable, with a maximum reliability of 99%.
- They are extremely complex.
- They require expensive ground facilities and services.
- The limitations of rockets impact spacecraft design.
- Satellites should be resilient because there are no repair services in space.
- Components and devices must be space-qualified which are expensive, power-hungry, and massive.
- De-rating of components is required to prevent system overload.
- There is no mass production of satellites.
- Satellites must have redundancies in both hardware and functionality.
- Missions must be long-lasting and repositioning rates are low.
- There is extensive ground testing required.
- Development of satellites requires long times.
- Insurance is very expensive.
- Satellites should be resilient because there are no repair services in space.
- The thrust of rockets converts stored chemical energy into kinetic energy.
Multi-Stage Launcher Optimization
- The goal of multi-stage launcher optimization is to maximize the payload mass-ratio.
- To optimize a multi-stage launcher, each successive stage should have less mass than the preceding one.
- Stages with similar properties should deliver similar changes in velocity.
- Stages with large specific impulses should be placed above stages with smaller ones.
- Stages with larger specific impulses should deliver greater changes in velocity.
Figures of Merit
- The most important measure for a launcher is its payload capacity.
- The accuracy of orbit injection is critical, including the semimajor axis, eccentricity, and inclination.
- Launcher performance can be assessed using the C3 parameter, an astrodynamical parameter derived from the vis-viva equation.
Single-Stage to Orbit (SSTO)
- There are two SSTO design alternatives:
- Vertical take-off/horizontal landing.
- Vertical take-off/vertical landing.
- Horizontal landing reduces fuel consumption for vertical landing and provides added safety through gliding.
- Vertical landing saves weight by eliminating wings, but it does not allow gliding.
Electromagnetic Launchers
- Electromagnetic launchers, like railguns or mass drivers, accelerate payloads to high velocities.
- They offer advantages:
- Complete reusability.
- Low cost.
- High availability.
- Drawbacks include:
- High accelerations (up to 15000 g) experienced by the payload.
- Intense heat experienced by the payload unless launched from a vacuum.
Launchers for Small Satellites
- Modern launchers for small satellites should offer the following:
- Low cost.
- A favorable launch environment.
- Accurate orbit injection.
- The ability to accommodate secondary payloads.
- Dead launch capability.
- A range of on-site services like clean rooms and testing equipment.
- Launchers for nano and picosatellites include:
- Decommissioned ICBMs.
- New, low-cost, low-performance launchers.
- Piggyback launches.
- Shared launches on vehicles like Vega.
- For launchers to remain competitive with piggyback launches, costs should be less than $50,000 per kilogram of payload.
- Higher costs may be acceptable if the launch date and/or final orbit are user-selected.
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Description
Explore the complexities and challenges associated with rocket engines and launchers in space travel. This quiz highlights the disadvantages of current launch systems, their impact on spacecraft design, and the necessary adaptations for satellite resilience. Test your knowledge on the nuances of rocket technology and its implications.
