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연구방향

Challenges of Laser in Dynamic Space

Challenges of Laser in Dynamic Space

> 연구방향 > 우주잔해물 레이저제거
연구방향 > 우주잔해물 레이저제거

우주잔해물 레이저제거

우주잔해물 정의(IADC definition)

  • Space debris are all man-made objects including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional.

인공위성 현황

  • 1,071 인공위성이 운영 중에 있으며(2013.05.31. 기준), 궤도 특성에 따라 LEO, MEO, GEO 및 HEO 인공위성으로 구분함.
    1) Low Earth Orbit(LEO) : ~ 2,000km altitude
       - Mission : Remote sensing, Earth observation
         Orbit : 1.5 ~3 hour period, 7~8 km/s
    2) Medium Earth Orbit(MEO) : ~ 20,000km altitude
       - Mission : Navigation satellites(ex, GPS, GLONASS, Galieo)
         Orbit : 12 hour period, 4km/s
    3) Geosynchronous Earth Orbit(GEO) : 36,000km altitude
       - Mission : Communication/broadcast/weather satellites
         Orbit : 24 hour period, 3km/s
    4) Highly Elliptical Orbit(HEO)
       - Mission : Early warning satellites, polar communication coverage

우주잔해물 충돌위험

Physical Size Population Comments Potential Risk
to Satellites
CategoryⅠ
(<1 cm)
Many millions to billions Can be tracked
Effective shielding exists
Damage
CategoryⅡ
(1 to 10 cm)
LEO debris:400,000
Debris at all altitudes:750,000
Larger objects in this range Severe Damage or complete destruction
CategoryⅢ
(> 10 cm)
LEO debris:14,000
Debris at all altitudes:24,000
Can be tracked
No effective shielding
Complete destruction
  • The U.S. military tracks objects in space with radar and optical sensors in the Space Surveillance Network (SSN)
    Can track objects in LEO larger than 5-10 cm in size
    Can track objects in GEO larger than ~1 m in size
  • U.S. military keeps a Catalog of objects - currently >15,000 objects
  • To be in the Catalog:
  • the object must be tracked by SSN
  • the object's origin must be known
  • The total amount of debris is much larger than the number of objects in the catalog

우주잔해물 위협

  • 인공위성 작동 불가 확률 : 0.05%
  • 인공위성 충돌 확률 : 0.5%
  • 5mm 이하 우주잔해물 : 인공위성 표면에 흡수
  • 5 ~ 15mm 우주잔해물 : 인공위성 작동 불가
  • 15mm 이상 우주잔해물 : 인공위성 파괴

우주잔해물 충돌사건

  • 알루미늄을 이용한 Hypervelocity Impact 실험
    Aluminum sphere : 1.2 cm diameter
    Aluminum plate : 18 cm thick and 5 cm sphere at a 6.8 km/s impact

궤도별 인공위성 분표 현황


  • 2) Unintentional Collisions between Space Objects
년도, 내용순으로 표출
Year Event
1991 Inactive Cosmos-1934 satellite hit by cataloged debris from Cosmos 296 satellite
1996 Active French Cerise satellite hit by cataloged debris from Ariane rocket stage
1997 Inactive NOAA-7 satellite hit by uncataloged debris large enough to change its orbit and create additional debris
2002 Inactive Cosmos-539 satellite hit by uncataloged debris large enough to change its orbit and create additional debris
2005 U.S. rocket body hit by cataloged debris from Chinese rocket stage
2007 Active Meteosat-8 satellite hit by uncataloged debris large enough to change its orbit
2007 Inactive NASA Upper Atmosphere Research Satellite (UARS) believed hit by uncataloged debris large enough to create additional debris
2009 Retired Russian communications satellite Cosmos 2251 collides with U.S. satellite iridium 33
2013 Ecuadorean satellite Pegasus collides with debris from an S14 Soviet rocket launched in 1985

우주잔해물 제거 정책

  • UN COPUOS Space Debris Mitigation Guideline
    Limit debris released during normal operations.
    Minimize the potential for breakups during operational phases.
    Limit the probability of accidental collision in orbit.
    Avoid intentional destruction and other harmful activities.
    Minimize potential for post-mission breakups resulting from stored energy.
    Limit the long-term presence of spacecraft and launch vehicle orbital stages in the low Earth orbit (LEO) region after the end of their mission.
    Limit the long-term interference of spacecraft and launch vehicle orbital stages with the geosynchronous Earth orbit (GEO) region after the end of their mission.

  • UN-related Institutions relevant to International Space Security

Source : Space Security Index 2013

우주잔해물 제거 방법

    1) 능동적 제거 방법
  Catalog Ⅰ
(size < 1cm)
Catalog Ⅱ
(size 1 ~ 10cm)
Catalog Ⅲ
(size > 10cm)
LEO orbit Space-based Magnetic Field Generator
Sweeping/Retarding Surface
Space-based Laser
Ground-/Air-/Space-based Laser Drag Augmentation Device
Magnetic Sail
Momentum Tethers
Electrodynamic Tethers
Capture/Orbital Transfer Vehicle
(Space Shutter)
GEO orbit     Solar Sail
Momentum Tethers
Capture/Orbital Transfer Vehicle
(Using Net or Tentacles)
    2) Laser를 이용한 방법
  • Ground- and air-based laser
    - provide a very high power
    - technology is mature
    - energy lose significantly by the atmospheric absorption
    - could not be move freely in a huge range

  • Space-based laser
    - no negative atmospheric effects
    - be able to track and target debris with a much larger field of view
    - focus on targets for longer periods of time
    - the cost is much larger to build, lunch and operate
    - can be a space-based weapon system

  • A US project named ORION is aimed on the effectiveness of using ground-based laser to clear up the space debris in LEO. For most LEO debris, the change of its velocity can be completed in a single transit of the debris.

  • In 2000 the US invested $ 200 million to research the ground-based laser experiment to clean up debris, and intended to have the experiment in 2003.

Schematic of laser system and operations

Source : Space Security Index 2013