A lot. Going with the Saturn V, since information about it is widely available: 4 hold-down clamps that put out 350 metric tons each. http://www.hq.nasa.gov/pa

A lot. Going with the Saturn V, since information about it is widely available: 4 hold-down clamps that put out 350 metric tons each. http://www.hq.nasa.gov/pao/History/SP-4204/ch13-4.html http://www.hq.nasa.gov/pao/History/SP-4204/ch13-4.html Best tape I can find in 20 seconds of googling: "Super Strength II: super heavy duty tape with 400 lbs of tensile strength (meets OSHA 29 CFR Part 1926.502)" http://www.reefindustries.com/barricade-tape.php http://www.reefindustries.com/barricade-tape.php That's nearly 2000 layers of tape for each hold-down clamp, or 8000 total. How many meters of tape that is depends on how much tape is needed per layer per clamp. Lets say two meters, so we're talking 16km of this heavy-duty tape. That super-heavy duty stuff comes in 300' rolls, so you would need 175 rolls of it to hold down a Saturn V right at launch. That is just right at launch though, when the fuel inside the rocket is doing most of the "hold the rocket down" work. As the rocket burns more and more fuel, you will need more and more tape to hold it down. A smaller rocket like the F9 will require less tape.