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Comment Re:this information has been available for years (Score 3, Informative) 31

I remember partly by accident bypassing the BIOS password on a Dell laptop in 2009 via the battery connector, and again deliberately (where a student had set a BIOS password on the school laptop) in 2013.

On Dell desktops there is even a Dell knowledge base article and a dedicated jumper specifically for resetting the BIOS password. The same with Dell and IBM servers (again with first-party instructions).

Comment Re:Calculations (Score 3, Informative) 99

Even with 3.6GPa ultimate tensile strength (2.75x10^6 N.m/kg specific strength) of carbon nanotube ropes, it won't work.

Assuming a 2 tonne craft (as specified in the article), assuming 100% loading:

  • cross-sectional area: 10^5N / 3.6x10^9N/m^2 = 2.77x10^-5m^2 = 27.7mm^2
  • mass assuming 1000km rope: 10^6m x 2.77x10^-5m^2 x 1300kg/m^3 = 3.6x10^5kg = 36 tonnes of rope for a 2 tonne vessel.

Required specific strength, assuming a rope with a mass of 2 tonnes, giving a total mass of 4 tonnes: (10^6m x 2x10^5N) / 2x10^3kg = 1x10^8 N.m/kg

Comment Re:Seriously long tether needed (Score 1) 99

You're talking about something that is compact and has a mass of between a few grams and a few tens of kilograms.

The article is about a 2 tonne spacecraft attached to a tether, which is anchored by a harpoon, and the article talks about braking forces of less than 5G.

A 500km long carbon nanotube rope (3600MPa Ultimate Tensile Strength) strained to 75% breaking strength (2700MPa) and handling a force of 200 kilonewtons (2 tonnes times 10G) would need to have a cross-sectional area of about 70mm^2, and would have a mass of about 50kg.

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