An Air France jet falls out of the sky over the Atlantic Ocean, pitot-tubes are blamed but otherwise there is little clue as to the cause. Several passengers and crew are injured when aircraft in cruise encounter severe turbulence. Tennis-ball size hail demolishes part of the historic wine-growing region in Hungary. Tornados ravage villages in Austria and forests in the Tatra Mountains in Slovakia… The list goes on.
True, clear air turbulence has been described decades ago, severe storms have happened before and the chance of space junk reaching altitudes where we fly is negligible. So we are ok. Or are we??
There are currently some 16,000 pieces of space junk larger than 10 centimeters wide circling Earth and the existing monitoring system can only track stuff at least 50 centimeters across. Of course these leftovers from celestial mid-airs and the fancy of some States’ military leaders represent a danger first and foremost for space vehicles. A new worldwide system is in the make that will be able to track everything in medium- and low-Earth orbit 5 centimeters and larger and issue a warning if a collision is likely… with another spacecraft. But not all spacecraft can be moved to get out of the way and hence more collisions are likely, meaning more space junk. It is only a matter of time before there will be pieces large enough to enter the lower atmosphere without burning up. Who knows, some may have strayed down already streaking over the South Atlantic…
Severe storms involving dangerous wind speeds and levels of turbulence, super-sized hail and other nasties have become much more frequent and they are now visiting parts of the globe hitherto known more for their stable seasonal weather. As the energy in the atmosphere grows with the rise of average temperatures, so do the severity of storms and their global reach. Aircraft design limits established in gentler times may need to be reconsidered and the advice to walk around in the cabin to counter deep-vein thrombosis replaced by three point safety belts and exclusively in-place exercise…
Both SESAR in Europe and NextGen in the USA are working on a new air traffic management system that is trajectory based and will enable traffic density and complexity to rise to hitherto unseen levels. This is essential to accommodate the expected traffic growth. Trajectory based operations (TBO) involve aircraft flying very precise four dimensional trajectories (three spatial dimension and time) with separation between aircraft maintained on the legal minimum at all times to maximize throughput. Such a closely coupled and finely tuned system operating at maximum efficiency requires relatively stable conditions in the atmosphere to be viable.
The exact thing global warming is likely to deny us and, unfortunately, probably much sooner than we like to admit.
The incidence of space junk encounters is likely to remain low and tracking system enhancements can minimize the dangers. But severe weather en-route and around airports is another matter altogether.
Improvements to weather forecasting and the better integration of meteorological information into the ATM system via SWIM are certainly part of SESAR. But how will the system cope when the forecast weather materializes and when there will be more and more of it around?
The SESAR implementation horizon is 2020. If we consider the way strange weather phenomena have grown over the past 20 years and how change is accelerating, may be it is time to ponder how we will counter such effects in 2020. Or sooner…