STS-94, July 15, 1997, MET:14/11:01 (approximate). One of the final runs of the TEMPUS experiment shows heating of a sample. At the point this image was taken, the sample was in the process of melting. The surface of the sample is beginning to flow, looking like the motion of plate tectonics on the surface of a planet. During this mission, TEMPUS was able to run than 120 melting cycles with zirconium, with a maximum temperature of 2,000 degrees C., and was able to undercool by 340 degrees - the highest temperature and largest undercooling ever achieved in space. The TEMPUS investigators also have provided the first measurements of viscosity of palladium-silicon alloys in the undercooled liquid alloy which are not possible on Earth.

MOVIE! 501KB mpeg movie shows the melt cycle of this sample and the flows on the surface

STS-94, July 15, 1997, MET:14/10:34 (approximate). In all, seventeen tests were completed for the Laminar Soot Processes (LSP) experiment - three more than originally scheduled. Study of the downlink data of LSP has already resulted in discovery of a new mechanism of flame extinction caused by radiation of soot. Scientists found that the flames emit soot sooner than expected. These findings have direct impact on spacecraft fire safety, as well as the theories predicting the formation of soot - which is a major factor as a pollutant and in the spread of unwanted fires.

MOVIE! 506 KB mpeg movie shows the ignition and extinction of this flame.

STS-94, July 15, 1997, MET:13/16:00 (approximate). The Coarsening in Solid-Liquid Mixtures (CSLM) experiment continues today in the Middeck Glovebox in the Spacelab module. This image shows the front-panel Liquid Crystal Display on this experiment, which keeps track of various parameters of the experiment run. Although there is no video or image downlink of a number of experiments that took place on board STS-94, that doesn't mean they didn't have any action! CSLM, the Plant Growth Bioprocessing Apparatus (PGBA), The Vapor Diffusion Apparatus (VDA-2) and the Protein Crystallization Apparatus for Microgravity (PCAM) (two protein crystal growth experiments), and the Physics of Hard Spheres (PHaSE) , and materials science experiments conducted in Japan's Large Isothermal Furnace, all have reported success in their experiment runs carried out on board Columbia on this mission. Today's feature story is on the Microgravity Measurements Assembly (MMA), one of four sets of instruments on board which monitor the microgravity environment so the other experiments can be successful!

After the shuttle lands, the scientists on the ground will be able to get all the data gathered and samples tested during this trip to orbit, head for home, and begin their detailed analyses, a process which is part of the ongoing scientific process.

STS-94, July 14, 1997, MET:12/12:51 (approximate). In the early morning hours, scientists for TEMPUS , a German acronym meaning "containerless electromagnetic processing in weightlessness," monitored the solidification of an undercooled metallic sample. An undercooled sample is a sample that is still a liquid, even though its temperature is below its normal solidification temperature (like trying to keep water from turning into ice in your freezer!) . An undercooled metallic sample solidifies so fast, it gives off a flash of light! The light pulse's source of energy is from the energy of motion of the molecules moving with respect to each other in the sample while it's still a liquid. When the sample freezes, the molecules stop moving, and their energy is converted into electromagnetic energy - in this case, visible light. Scientists actually stimulate the freezing by using a needle to prod the sample to solidify - the needle also gives them a reference point to understand exactly how the sample solidified.

The July 14 feature story is on TEMPUS, the important phenomena scientists are studying, and their application in materials processing on Earth.

In the image above, you see a double image (an artifact of the recording camera) of a TEMPUS sample, the clock information at the top, and a short band of interference just below the top image. We have an mpeg movie (807KB) showing the pulse of light from the rapid solidification of this sample, from a TEMPUS run this morning at 2 a.m. CDT.