Meteoroid and debris shielding


ESA activities related to protection of spacecraft against hypervelocity impacts (space debris or meteoroids) go back to the Giotto programme. The motivation in the early eighties was to ensure the mission success by a proper design and an adequate verification of the spacecraft shield against the comet Halley’s dust tail. Most of the work performed during the nineties was devoted to exploring possible protections for the European Module of the Space Station (Columbus and ATV). The driver here was to ensure the manned pressurized module would not leak after a space debris impact with a high probability of success. This was needed to comply with safety requirements linked to the presence of man on board. More recent work has focused on unmanned spacecraft. The logic here recognizes the very constraining limitation linked to requirements similar to the one used for manned modules: no perforation of the main body. The new approach is thus to accept perforation of the spacecraft structure and to assess the vulnerability of mission critical equipments (Pressure Vessels, batteries, electronic boxes, harness). This technological field can be broadly split into three domains:
 
  1. Material and configurations characterisations under hypervelocity impacts
  2. Experimental and diagnostic techniques
  3. Validation of numerical simulations
Each of these domains is driven by stringent requirements linked to the nature of hypervelocity impacts:

Very short transient (time scales in microseconds)

Materials under high strain rates (104 to 107 s-1)

Material phase changes (local pressures range up to mega-bars)

The final purpose of this effort which spans over more than 20 years is to support ESA programmes showing compliance of new spacecraft to the European Code of Conduct for Space Mitigation
 
 
EMI test 3915, 4.0 mm aluminium sphere, 7.2 km/s, 45 degrees
 
EMI test 3915, 4.0 mm aluminium sphere, 7.2 km/s, 45 degrees 1.2 mm Al7075 bumper 49.5 mm spacing 3.3 Al7075 backwall
  
 
Hypervelocity impacts on pressure vessels
 
Hypervelocity impacts on pressure vessels. Shadowgraph pictures of fragment cloud at different pressures and numerical results (5 mm aluminium sphere, 5.2 km/s)
  
 
High Speed Video Shadowgraph of Exp. 3931
 
 
 
 High Speed Video Shadowgraph of Exp. 3931; shutter time 80 ns (pict. 1-6) Exp. 3931: Whipple shield, 1.2 mm Al 7075-T73, S=49.5, 3.3 mm Al 7075-T7351, Al-projectile d=4.999 mm,
v=7.0 km/s, α =60°, result: > BL
 
 
High Speed Video Shadowgraph of Exp. 3938
 
 
 
 High Speed Video Shadowgraph of Exp. 3938; shutter time 80 ns (pict. 1-2) Exp. 3938: Whipple shield, 1.2 mm Al 7075-T73, S=49.5, 3.3 mm Al 7075-T7351, Al-projectile d=6.003 mm,
v=7.1 km/s, α =75°, result: < BL
 
 
 
AUTODYN-2d sph simulation, key features of material response during impact
 
Hypervelocity impact simulation on Columbus shield (2.5 mm aluminium first bumper, 4 Nextel/ 18 Kevlar- epoxy second bumper, 4.8 mm aluminium rear wall, total spacing 130 mm). 15 mm aluminium sphere, 10 km/s.
Left : t= 5 μs, centre, t= 10 μs, right, t= 90 μs.
 
 
  
Last update: 31 July 2007