The tubes are 1/2" diameter, and commonly used in Bubble Tea shops as drinking straws. They are rigid, light weight, but strong.

We supply replacement tubes free of charge to our customers. They seem to stand up to the task, but if they get lost or damaged, give us a call. In a pinch, you might find a bubble tea shop near you.

Bubble Tea straws are usually cut off at a sharp angle at one end. They must be modified so that they are perfectly square at both ends.

We use a table sander for this, taking care to make them all 7.5 inches long.

Sometimes, depending on line tension, line length, and the aerodynamics of a particular spacecraft, the line can vibrate, causing the tube to dance a little on the line. In extreme cases, the tube may hit the sensor prior to the spacecraft arrival, causing a false hit.

You should always allow an inch of space between the tube and the sensor.

One customer wrote in with this solution to dancing tubes: He weighted it down a little by winding some solder wire around it.

How much solder? Experimenting will tell you what is best for your track.

You want to use enough to make the tube stable. But you don't want to make it so heavy that a spacecraft that has nearly run out of energy won't be able to bump it into the sensor.

After winding the solder, it is held in place by some teflon plumber's tape. This makes a neat job of it, but I guess any kind of tape would do.

 

The Space Derby finish line is a new product. If you have solved any problems, please let us know. We are always ready to improve our products.