Challenges of Laser in Dynamic Space
Challenges of Laser in Dynamic Space
> 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
- 2) Unintentional Collisions between Space Objects
| 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.
Source : Space Security Index 2013