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Welcome to the Rotating Target Source Website!

This website will tell you all about how the new RTS system works, what ADR and x-ray calorimetry are, a project timeline and student bios, and much more!

What is a Rotating Target Source anyway?

The Original RTS Machine
The Original RTS Machine (photographed at Goddard)
During the summer of 2004, six Olin College students were hired by the NASA Goddard Space Flight Center to improve their Rotating Target Source (RTS), a box enclosing a rotating wheel that emits characteristic x-rays used for calibrating an x-ray calorimeter. An adiabatic demagnetization refrigerator (ADR) linked with an x-ray calorimeter was set to launch in February 2005 from Japan, and this RTS would be used to calibrate it. Before the project began, researchers at Goddard drove the motor inside the RTS with a simple power supply. When they wanted to spin to a certain point on the wheel, they turned on the power supply until the wheel was in the right position. If they overshot, they had to go back around again. They could never be exactly sure where they were and had little accuracy in their control.

Olin Students at Goddard
Olin Students and Faculty in a Goddard Clean Room
The Olin students were given the opportunity to change this by designing a system that would rotate the wheel to exactly the right position at any given moment. This was achieved with a motor control amplifier (MCA), a shaft encoder, and a Macintosh. In the end, the NASA researchers had a simple C program they could run from the Terminal of Mac OS X that gave them the ability to immediately rotate to any position on the wheel, jog the wheel clockwise or counterclockwise, or spin the wheel at a constant rotation. Due to launching deadlines, the RTS was immediately flown to Japan for ADR calibration, where it performed its job as defined. It was a great opportunity for the Olin students to work on something of practical application that covered so many technical areas.

So, what's an ADR?
Good Question. You should probably check that out at the ADR Website.

Copyright 2004. Contact the NASA List at nasa@lists.olin.edu . Last Modified: July 20 2004.