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1. Space Environment
Lecture 27 – Space Debris (Vol. 2)
Hypervelocity collisions
Professor Hugh Lewis
SESA3038 Space Environment

2. Overview of lecture 27
• In this lecture we focus on hypervelocity collisions that have taken place in
the LEO region, including some recent ASAT tests:
– Fengyun 1C ASAT test in January 2007
– Iridium 33-Cosmos 2251 collision in February 2009
– Microsat-R ASAT test in March 2019
• We look at the consequences of these events in terms of their impact on the
environment
• We also put the consequences of these events into the context of the top 50
debris-producing objects in history (up to 2019!)
Space Environment – Space Debris (Vol. 2)

3. Space debris Space Environment – Space Debris (Vol. 2)
• The space debris environment: update
• Space surveillance/measurement of space debris
• Impacts on space operations
• Modelling of space debris
• Environment/evolutionary modelling
• Impact modelling
• Breakup modelling
• Re-entry modelling
• On-ground risk modelling
• Clean Space
Volume 2 (Week 6)

4. Growth of the orbital population Space Environment – Space Debris (Vol. 2)
Data from NASA Orbital Debris Quarterly Newsletter (April 2020)
https://orbitaldebris.jsc.nasa.gov/quarterly-news/

5. Historical fragmentation events Space Environment – Space Debris (Vol. 2)
Data from ESA’s Annual Space Environment Report (September 2020)

6. Fengyun 1C: January 2007 Space Environment – Space Debris (Vol. 2)

7. Iridium-Cosmos: February 2009 Space Environment – Space Debris (Vol. 2)
• Iridium 33:
• Active commercial communications satellite
• ~700 kg
• Cosmos 2251:
• Inactive military communications satellite
• ~900kg
• Collision on 10th February 2009
• ~790 km altitude
• ~11.7 km/s relative speed
• 4.7 × 1010 Joules (10 tonnes TNT)
– 52,000 Joules (11 kg TNT) for every gramme
of Cosmos 2251

8. Iridium-Cosmos: February 2009 Space Environment – Space Debris (Vol. 2)
Credit: Ruediger Landmann https://www.thespacereview.com/article/1314/1

9. Iridium-Cosmos: February 2009 Space Environment – Space Debris (Vol. 2)

10. Spatial density: June 2009 Space Environment – Space Debris (Vol. 2)
Iridium 33 &
Cosmos 2251
fragments
Fengyun-1C fragments
https://orbitaldebris.jsc.nasa.gov/quarterly-news/pdfs/odqnv13i3.pdf

11. MICROSAT-R: March 2019 Space Environment – Space Debris (Vol. 2)
Indian Anti-satellite (ASAT) test 27
March 2019
• Approx: 05:40 UTC (Dr Marco
Langbroek)
• Suspected Kinetic Kill Vehicle (i.e. not
an explosive warhead)
• Target: MICROSAT-R
• 259 km x 279 km orbit
• 96.6 degree inclination

12. MICROSAT-R: March 2019 Space Environment – Space Debris (Vol. 2)
At 05:40 UTC MICROSAT-R was moving Northwards towards Abdul Kalam

13. MICROSAT-R: cloud evolution Space Environment – Space Debris (Vol. 2)
The test was conducted to minimise the orbital lifetime of the debris

14. Top 50 debris-generating objects Space Environment – Space Debris (Vol. 2)

15. Recap of lecture 27
• In this lecture we focused on hypervelocity collisions that have taken place
in the LEO region, including some recent ASAT tests:
– Fengyun 1C ASAT test in January 2007
– Iridium 33-Cosmos 2251 collision in February 2009
– Microsat-R ASAT test in March 2019
• We looked at the consequences of these events in terms of their impact on
the environment and we put these into the context of the top 50 debris-
producing objects in history
• In the next couple of lectures we will start to see how some of these events,
and others, have affected satellite operations in LEO
Space Environment – Space Debris (Vol. 2)