Burning space junk in the atmosphere of 9 March 2016

The map above shows the location of the possible reentry of the space junk CZ-4C R/B (36835U) predicted by modeling of orbital evolution until the fragment or satellite reaches the altitude of nominal burst.
According to the forecast made by Satview.org, the object’s reentry will occur in Wednesday, 09 Mar 2016 at 12:18 UTC, above the coordinates shown on map.
The second map shows the location of the reentry like predicted by USstratcom (United States Strategic Command).
Update Mon 7-Mar-2016 7:10 UTC

The Satellite Path 
The path to be followed by satellite (dotted line) does not change due to the fact that the satellite is falling and can be used to assess the trajectory of the object before and after possible fall. In the graph, each point marks the range of 1 minute. 
Solar Flux and Other Variables 
As much as the institutes and space agencies strive to provide correct data of the point where the space debris will fall, several factors may interfere with the accuracy of the prediction. Among the most important, the solar flux is the most critical because it determines the conditions of the upper atmosphere, increasing or decreasing the drag on the object.
Besides the solar flux acting on the aerodynamic characteristics, another variable rather difficult to be computed is the resistance of materials used in the construction of the object and the shape of the structure. Combined, these factors may determine different altitudes for the moment of rupture, causing errors of more than 30 km in altitude reentry provided.
Other variables that affect the calculation of reentry, although less important, are the gravitational perturbations of the Sun and Moon and also those exercised by large mountain ranges, above or below sea level.
The modeling used by Satview to compute the time of reentry uses solar flux data obtained at the time of modeling, and prediction of the behavior of the sun for the next 5 days. With this, the margin of error of prediction is + / – 3 revolutions for satellites or debris in uncontrolled reentry. 
Altitude of Reentry 
Spacecraft reentering the atmosphere without control usually break between 72 and 84 km altitude due to temperature and aerodynamic forces acting on the structure.
The nominal breakup altitude is 78 km, but big satellites that have larger and denser structures survive longer and break down at lower altitudes. Usually, solar panels are destroyed before any component, at altitudes between 90 and 95 km.

Fire in the Hole: Studying How Flames Grow in Space

Understanding how fire spreads in a microgravity environment is critical to the safety of astronauts who live and work in space. And while NASA has conducted studies aboard the space shuttle and International Space Station, risks to the crew have forced these experiments to be limited in size and scope.

Now a new experiment, designed, built and managed at NASA’s Glenn Research Center, will ignite an understanding of microgravity fire on a much larger scale. The Spacecraft Fire Experiment, known as Saffire, is a series of experiments to be launched on three different flights beginning in March.

“A spacecraft fire is one of the greatest crew safety concerns for NASA and the international space exploration community,” says Gary Ruff, Saffire project manager.

Saffire will involve far larger flames than previous experiments and will investigate the way fire spreads on a variety of combustible materials. Because the experiments will be conducted away from the space station, there is no risk to the astronauts aboard.

Each Saffire experiment will be remotely operated inside a 3 x 5 foot module, split into two compartments. One side of the module is an avionics bay that contains sensors, high definition video cameras and signal processing equipment. The other side contains the hardware required to ignite a large flame and burn the fabrics and materials inside.

When the experiments begin, Saffire I and III will burn one large 16 by 37-inch piece of SIBAL cloth, which is a blend of fiberglass and cotton. This material has been studied in previous microgravity combustion experiments, although at a much smaller size. The SIBAL cloth will be burned from the bottom to see how the flame spreads. If the flame extinguishes itself, scientists will light it at the top and see what happens as the flame moves opposite to the airflow.

Saffire II, scheduled to launch in May from Wallops Flight Facility in Virginia, will ignite a mix of nine different samples of materials used routinely on the space station including flame retardant fabrics used for astronaut clothing, station Plexiglas window samples with edge variations and structures used for storage containers and silicone composites. Each sample is two by 11 inches, the size sample NASA uses to screen materials on Earth before they are used on a spacecraft.

“Saffire seeks to answer two questions,” says David Urban, principle investigator. “Will an upward spreading flame continue to grow or will microgravity limit the size? Secondly, what fabrics and materials will catch fire and how will they burn?”

The Saffire I payload will hitch a ride on a resupply mission to the space station in an Orbital ATK Cygnus cargo vehicle from Kennedy Space Center in Florida. When Cygnus arrives, astronauts will unload their supplies, but Saffire will remain on board Cygnus.

“Within the first day after Cygnus pulls away from the space station, we will begin the experiment, which will run autonomously once the RUN command is sent,” says Steven Sinacore, deputy project manager. “It will only take a few hours to run the experiments, but Cygnus will remain in space for seven days to ensure complete data transmission back to the Saffire operations team on the ground.” Eventually, Saffire, along with Cygnus, will be destroyed upon reentry into Earth’s atmosphere.

Concepts for additional Saffire missions- IV, V, VI are in development to focus more on flame spread, smoke propagation, detection and suppression of fire.

As NASA continues to send astronauts to the space station and continues the path toward a human mission to Mars, improving understanding of the structure of spacecraft fires is critical. “Saffire is all about gaining a better understanding of how fire behaves in space so NASA can develop better materials, technologies and procedures to reduce crew risk and increase space flight safety,” says Ruff.

Watch how the Saffire experiment will be conducted in space.
Credits: NASA