Seminar Raumfahrt und Terrestrik 2020
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Flashcards
Was sind die größten Highlights der Raumfahrt der letzten 20 Jahren?
- Mars Pathfinder 1998 (erste rover in einem anderen Planet)
- ISS 1998
- GPS 1995
- Enteckung der dunkle Energie/Materie 1998
- Entdeckung Exoplaneten.
- Verlassen des Sonnensystems 2012
- Cubesat standard 2003
- sub-orbital flug
- spacex falcon 9 Dragon
Was ist der ORION Spacecraft?
- Orion Multi-Purpose Crew Vehicle für 4 Astronauten
- Technologie ähnlich Apollo (Ablatives Hitzeschild, Fallschirm, etc.)
- Kombination mit ATV-basiertem (Automated transfer vehicle) europäischen Service Modul Orion Testflug 2014 / SLS-Orion Start 2020 / Bemannter Start 2022
Was ist der Deep Space Gateway?
Aufbau einer neuen Raumstation (ISS Nachfolge) um den Mond Ausgangspunkt für Mond-Exkursionen/Mond Basis und weiteren Raumflügen (Mars) Zusammenarbeit NASA, Roscosmos, ESA, Japan, …
Was sind beispiele für advanced pruplsion?
- Solar sails
- MAgnetic sails
- Tethers
- beamed energy
- photon rocket
Was macht ESOC?
European Space Operations Centre. ESA's center for mission operations.
- study and develop tech.
Was wird an der TU Dresden ILR Raumfahrt gefroscht?
- Aerospikes
- Triebwerke
Was sind Herausforderungen bei Aerospikes?
Kühlung und Shubvektorsteuerunng.
Was ist SVSSI?
Schubvektorsteuerung durch sekundäre injektion.
How is space debris generated?
- Explosions,
- crashes,
- unintentional self ignition of residual fuel.
- Liquid metal fuel droplets,
- solid motor slag,
What are space debris sinks?
- natural decay:
- atmospheric drag
- gravitation of the sun and moon
- Solar radiation pressure
- Active maneuvers
- Deorbit by retro boost
- recovery
Where is most space debris?
from 700 to 900 km high orbits.
What size are the most dangerous objects (space debris)? Why?
Objects from 1 to 10 cm big. They are too small to track and to large for any protective measures.
Which satellites are most likely to collide?
Sun-synchronous satellites and russian satellites/rocketbodies. (inclinations from 82 to 91)
What facilities are necessary to develop and qualify CubeSats?
- Vibration facility
- Shock Table
- Thermal vacuum chambers
- Solar simulator
- Helmhotz cage (electromagnetic field control)
- Outgassing facility
Was sind typische Eigenscchaften von Cubesats?
- circa 2 kg
- Geometrie und Volumen mit U's definiert (1U = 10*10*10cm)
- suubsystems
- Scientific instrument
- GPS
- OBC (on board computer)
- UHF transmitter/ antennaes
- PPU (power processing unit)
- akkus
- solarzellen
- propulsion
How to ensure that a cubesat will survive the harsh conditions in space?
Tests:
- Functional Testing
- Power generation and consumption test
- propulsion test
- extensive environmental test
What are the objectives of PEGASUS?
- measure the thermosphere
What are the objectives of CLIMB cubesat?
- Measure the radiation in the Van Allen Belt.
- assess the capability of the indium microthruster FEEP
Is space radiation an issue for CubeSats?
we dont know we need to measure more
How to avoid radiation problems?
- shielding
- redundancy
- reset operation
Why have a Space Elevator?
- Getting to space without rockets
- Reducing energy to reach any orbit (GEO, beyond)
- drastically reduce cost per kg to space
What is a space elevator?
A tensile structure anchored at the equator and extending way beyond GEO.
- Tether length minimum 143780 km
- The unanchored system without countermass m_tip is balanced ar R_geo
- add counter mass m_tip to provide tension T0 at earths anchor point
- Larger counter mass shortens the length (after GEO), is less convinient
How does a space elevator work?
It uses the rotational energy of the earth to launch objects into space.
distances from mercury to Jupiter are reachable with rotation alone.
How and where to place the anchor point for a space elevator?
- At earth's equator
- near a local minima of the earth's gravity field
- with a moveable platform
What are some issues with the space elevator?
- needs material with very high specific strength
- large orbital objects as obstacles
- lightning and atmospheric events
- van allen radiation
- erosion by atomic oxygen
- tether vibrations
Was sind Systemaspekte von einem elektrischen Raumfahrtantrieb?
- Massenbudget
- Leistungsbudget
- Elektronik
- Redundanzkonzept
- Manövereffizienz
- Operations
- Anordnung
- Qualifikation
Was sind vorteile und nachteile von elektrische Antriebe gegenüber chemische Antriebe?
Vorteil: Es ist nicht gebunden an die innere eneergie des treibstoffes.
- ISP: 500 - 5000s
- Schub: 1 - 500 mN
- Power: 13kW
Nachteil: Energie muss aus externe Quellen gezogen werden.
- ISP: 220 - 320s
- Schub: 1 - 500 N
- Power: 3000 MW
What is the WMO and what do they do?
The world meteorological organization WMO.
It is the United Nation's voice of authority on weather, climate, water, and environment.
What are the purposes of the WMO?
To facilitate worldwide cooperation about meteorological and geophysical observations.
To promote rapid exchange of information.
To promote standardization.
To be applied in aviation, shipping, agriculture, and research.
What is the value of space-based weather observations?
One-third of the earths surface can be surveyed at one time.
What are technological challenges of electric propulsion?
Microthruster development. (For nanosats)
High power thrusters (5-20kW) with low power to thrust ratio.
Long lifetime qualification.
Cost reduction. Use of COTS
Spacecraft-thruster interactions.
Flight opportunities.
What are opportunities for use of electrical propulsion?
Telekommunikation market.
Navigation science and exploration.
Interplanetary missions, missions that need high accuracy (LISA)
Sat. Constellations
What kind of interactions between atomic oxygen and a spacecraft are there? And where?
At 80-200km height:
Atmospheric drag,
Erosion,
Degradation of solar cells,
Degradation of instrumentation
