Space Transportation Flashcards
What is the definition of mobility?
The ability to move freely or be easily moved
What are the building blocks of self-sustaining space mobility?
- Transportation (access to space, in-space transfer, re-entry and landing, planetary exploration)
- Harvesting and preparation of in-space resources
- Refurbishment, incl. refueling
What are segments of space transportation systems?
- Earth-to-suborbital
- Earth-to-orbit
- In-orbit
- Planetary entry/landing
- Low gravity-to-orbit
- Interplanetary/deep-space
- Return and re-entry
What is a space transportation system comprised of?
- Vehicle (Space Segment)
- Interfaces (to Payload, to Ground Segment)
- Ground Segment
- Payload
- Concept of operations
What are important factors to pick (1) and design (2) a space transportation system?
1.
- Performance
- Price
- Availability
- Reliability
- Service level
2.
- Performance
- Price
- Availability
- Reliability
- Launch site
What is something important to consider for space transportation systems when travelling between objects?
The delta v requirement to get where you need to be
What does the total launch mass of a spacecraft consist of?
- Structural mass mS
- Engine mass mM
- Propellant mass mPR
- Payload mass mP
What mass should be as small as possible in launcher systems (1) and what is the ratio of this mass to the total mass in today’s launcher systems (2)?
- Structural mass
- Around 0.12
What is staging (1) and what does it achieve (2)?
- No longer required structure is separated and doesn’t need to be accelerated anymore
- To obtain a maximum delta v (since Ratio of propellant is 1 in this case, thus the other ratios should be near 0), the structural ratio is minimised
What effect does staging have on the rocket equation?
The total delta v comprises of the delta v’s of all stages, meaning the initial mass of each stage is divided by each end mass and added in the equation
What is sequential staging?
Launcher consists of more than one stage, which sequentially become operational
What is parallel staging?
The stages burn simultaneously (but can have different total burn times), can lead to high acceleration but also high loss due to higher aerodynamic resistance
What does a high number of stages lead to?
Higher delta v, but also higher complexity and cost
What are some (6) satellite classes?
- Large (>1000kg)
- Mini Smallsats / Light (100-1000kg)
- Micro (10-100kg)
- Nano (1-10kg)
- Pico (0.1-1kg)
- Femto Satellite-on-a-chip (0.01-0.1kg)
How many orbital launches were there in 2019 (1) and 2022 (2) respectively, and how much total spacecraft was carried in both years?
- 102 (492 spacecraft)
- 186 (2521 spacecraft)
What are the top 3 international actors for spacecraft launches?
- USA
- China
- Europe
What launcher system has a large cost per kg (1), what system has a low cost (2) and what is the general trend from a decade ago to today (3)?
- Space Shuttle
- Starship
- Launching is ten times cheaper
What makes up the highest percentage of first and second stage weight, but has a really low cost?
Propellant
What costs the most in first stage (1) and second stage (2)?
- Engine
- Split between Engine, Structures and Avionics and Electrical
What are the main components and subsystems of a launcher system?
- Propellant
- Structure (incl. mechanisms like landing gear, payload adapters)
- Propulsion subsystem(s)
- Electrical subsystem and software
- Thrust-Vector Control
- Attitude and Control
- Separation subsystem(s)
- Pyrotechnical chain
- Re-entry Thermal Protection
- Recovery / Landing
What are the main parameters of a launcher system?
- Number and delta v increment of stages
- Mass contributions (Propellant, structural mass, mass at stage separation)
- Performance parameters of engines (Specific impulse, thrust)
- Global launcher parameters (Launch mass, Thrust-to-Weight ratio at launch, maximum acceleration of stages, payload environment)
What are some important considerations for the launch site?
Boundary conditions (Humidity, Side winds, Rain, Temperature, Gusts, Ions, Meteorites, Debris)
What are some (3) important requirements for launcher systems?
- Policy aspects (Planning, Cost, Industrial policy)
- Technical aspects (Performance, Environment, RAMS (Reliability, Availability, Maintainability, Safety)
- Exploitation aspects (Exploitation, Mission preparation, Operations, Services)
What are some (6) policy requirements of launcher systems?
- Guaranteed access to space
- Environmentally friendly
- Maintain and ensure space transportation competence with long term perspective
- International activities
- Ensure access to and transportation in space for lowest overall cost
- Competitive on the commerical launcher market
