Henderson, Don | Search NASA

NASA NTRS2014

Induction Heating of Hypervelocity Impact Samples to 2500 Degrees Centigrade

The Remote Hypervelocity Test Laboratory (RHTL) at White Sands Test Facility (WSTF) was asked to heat samples up to 2500 degrees Centigrade (4532 degrees Fahrenheit) to simulate reentry scenarios of crafts where heated shields are impacted with single small particles ranging from 0.2 to 1.0 millimeters (.008 to.039 inches) of various materials. The team decided an electromagnetic induction (induction heater) was the best method to achieve and control the temperatures in a rapid manner. The samples consisted of three-dimensional carbon-carbon and two-dimensional carbon-phenolic, which are both electrically conductive. After several attempts the team was able to achieve over 2500 degrees Centigrade (4532 degrees Fahrenheit) in ambient atmosphere. When the system was moved to the target chamber and the vacuum system evacuated down to 250 millitorr, arcing occurred between the bus bars and tank, the feedthrough fittings that carried the coolant and current, and between the target sample and coil. To overcome this arcing, conformal coatings, room temperature vulcanization (RTV) silicone, and other non-conductive materials were used to isolate the electromagnetic fields.

Simmons, Joshua↗

NASA NTRS2007

A Discussion on Personnel Exposure to Posttest Byproducts from a 50-cal. Light Gas Gun

In January of 2002, employees working in the Hypervelocity Test Facility (HTF) at White Sands Test Facility (WSTF) began to notice common physical complaints. These included loss of smell, loss of taste, skin irritation, a burning sensation of the mucus membranes, and redness and chapping of the lips. These conditions extended to home during the weekends and throughout holiday breaks as well. Concerns about air contaminants were raised with regard to the operation of the .50-cal. two-stage light gas gun (2SLGG). Employees suspected that these conditions might be caused by air contaminants from small leaks at the gun pump tube joint at the breech, and exhaust gas entrainment into the WAC systems. The WSTF Industrial Hygienist (IH) was notified and samples were collected using the MIRAN infrared spectrometer (real time) air sampler on 08 January 2002 at the SO-cal. gun. The results from this screening test suggested the need for more detailed investigations with analytical sampling and analysis.

Henderson, Don↗