Contamination of orbital warehouses

Question

So I'm thinking about orbital warehousing of raw materials but I'm wondering whether one would actually need an orbital structure to store the goods inside or could you just strap a booster to the goods to keep them in their orbit and be done with it.

So does anyone know where I could find some hard figures concerning particle contamination of material in geosynchronous orbit?

Edit: Specifically thinking about solid, elemental, raw materials, the mainstays of Sci-fi tech and orbital mining like Iron, Nickel, and Titanium.

Answer 1

The Cosmic dust article on Wikipedia says that

The dust density falling to Earth is approximately 10⁻⁶/m³ with each grain having a mass between 10⁻¹⁶ kg (0.1 pg) and 10⁻⁴ kg (100 mg). [...] By one estimate, as much as 40,000 tons of cosmic dust reaches the Earth's surface every year.

In 1984, NASA lauched the Long Duration Exposure Facility, "a school bus-sized cylindrical facility designed to provide long-term experimental data on the outer space environment and its effects on space systems, materials, operations and selected spore's survival". It was retrieved in 1990 after orbiting Earth 32000 times:

• YouTube Video: Long Duration Exposure Facility Satellite (LDEF); description and history of the mission.

• YouTube Video: Long Duration Exposure Facility Satellite: "LDEF Update", 1990, NASA Langley Research Center: some of the results; the most interesting, from my point of view, is that outgassing from the space craft itself is a major contaminant of optical surfaces.

• "Lessons Learned from the Long Duration Exposure Facility", W. K. Stuckey, Space and Missile Systems Center Air Force Materiel Command, 1993. Plenty of potentially interesting material, most of it way over my head.

• "Analysis of Systems Hardware Flown on LDEF - Results of the Systems Special Investigation Group" by H. W. Dursch, W. S. Spear et al., Boeing Defense and Space Group, 1992:

  • 34336 total micrometeoroid impacts;
  • The largest particles encountered by LDEF were approximately 1 mm in size.
  • Most of these larger particles appear to possess natural origins (i.e., originated from comets or asteroids).
  • The mean impact velocity was of approximately 17 km/s.

  • In orbit, additional particulate contaminants accumulated as a result of impacts with meteoroids and space debris. These contaminants tended to be deposited very close to the impact, with concentration dropping off with the square of the distance from the impact, as would be expected. Impacts with surfaces projecting radially from the surface of LDEF, such as tray edges or bolt heads, resulted in the greatest amount of material being deposited on the surface of LDEF. The concentration of such debris could be very detrimental to optical systems within a few inches of the impact.

  • The most detrimental contamination event in orbit was the outgassing and redeposition of molecular contaminants on the surface of LDEF. The brown discoloration caused by a contaminating molecular film on the surface of LDEF was evident through the windows of the Space Shuttle Columbia as it approached LDEF. This brown film was widely dispersed over the trailing rows of LDEF and at the space and Earth ends. Closer examination in SAEF-2 following recovery permitted a much more detailed analysis of the film and its distribution. Large areas of the exterior surface were covered with a film a few hundred nanometers thick. In some areas it was as much as a few hundred micrometers thick and completely opaque. Analysis of the film indicated it was a polymer consisting of a combination of silicones and hydrocarbons. The ram facing trays appeared clean but surface elemental analysis of ram surfaces indicated a silica residue remaining from atomic oxygen attack on the brown film. An infrared analysis of the film and possible sources indicated that two systems had sufficient mass to be major contributors to the film: the thermal control paints and the silicone adhesives used with both fasteners (to enable fastener assemblies to survive vibration testing without a decrease in installation torques) and the bonding of Velcro to LDEF and/or experimenter hardware.

Answer 2

You would likely need a warehouse in order to store liquid/gaseous materials such as fuel. I'm not sure about particle contamination, but it seems it will depend on how sensitive your material is. If it is a giant iron filled asteroid, or a block of iron, it would be durable enough you should be fine leaving it in orbit. The question comes down to how sensitive your materials are to contamination and radiation.

However it might be better to simply put everything either in a warehouse, or strapped to the outside, as otherwise you would have to worry about collisions in a crowded orbit.