Airliner hit in flight by re-entering space object cracking windscreen - and it's not the first time

A Boeing 737 Max 8 airliner has been reported as being struck in flight by re-entering object, cracking its laminated windscreen (windshield), while flying over Utah at an altitude of 36,000 feet. The United Airlines flight UA1093, enroute to Los Angeles from Denver, diverted to Salt Lake City on 16 October. While pressurisation was apparently maintained via the inner windscreen laminations, the deformation caused by the strike was enough to leave the inner pane completely crazed with some small shards of glass even detaching. One of the pilots (the Captain) was slightly injured by lacerations to his arm during the incident which is now being investigated by the US Federal Aviation Authority (FAA). None of the rest of the six crew or 134 passengers was hurt. It has been suggested by the cockpit crew that the object was re-entering spacecraft debris.[caption id="attachment_123799" align="alignnone" width="716"]

Post on X by AeroAvianNew showing the damage. Courtesy: X/@aeroaviannews[/caption]https://x.com/AeroAvianNews/status/1980034259223216425Major re-entries of spacecraft and even space stations in the South Pacific have often resulted in NOTAM warnings to aircraft to avoid the area, most other debris comes in unannounced. For example, this was done for the commanded re-entry of the Mir space station, and will happen for the re-entry of the International Space Station in 2030. However, more often space debris returns unannounced - prediction of times and landing areas of naturally re-entering hardware remains a very inexact science.Airliner strikes by Space debris have happened before even if the FAA has not yet accepted this fact. On 25 December 1996 a China Southern Airlines Boeing 757 airliner, on route from Beijing to Wuhan, had the outer pane of its cockpit windscreen cracked by the strike of a mystery object - now thought to be a small surviving space debris part. Thankfully pressurisation was maintained, given that the altitude at the time was 31,500 feet. The aircraft made an emergency return to Beijing.While most concerns are over the possibility of space debris building up in orbit potentially going runaway as they strike each other as postulated in the 'Kessler Syndrome', most space operators now agree to lower orbits at the at of spacecraft's life which will allow a faster - if uncontrolled - orbital decay to re-entry. The problem for airliners is that with the mass launches of satellite constellations numbering thousands of spacecraft, as they re-enter, this is likely to increase the chance of airliners being struck by surviving space debris. The satellite parts most likely to survive are low radius spherical objects, especially small propellant tanks made out of stainless steel - a material which is, by the way, deliberately used for the internal structure/primary skin of the SpaceX Starship reusable spacecraft/stage as it can maintain its strength under the high temperatures of re-entry.Airliner flight remains a very safe way to travel with Western-built jets typically having annual fatal accident rates of 1 in 10 million. In comparison, according to the Slingshot Seradata database, the fatal accident rate for human spaceflight is at circa 1 in 100. Most space related strikes on the ground have usually involved falling or exploding stages during the launch. There has only ever been one incident involving a re-entering part actually striking someone. A woman called Lottie Williams, 48, was exercising in Tulsa Park, Arizona, on 22 January 1997, when she was hit by a blackened six inch re-entered piece of a Delta II rocket, but she walked away from the incident.The FAA officially rates the chance of an airline passenger being killed as the result of an aircraft being struck by a re-entering piece of space hardware at one in one trillion. Whether this is now re-assessed remains to be seen.Experts have noted that spacecraft debris is not the only possibility in this latest incident. Meteorites strike the Earth about 17,000 times per year. Orbital analyst Jonathan McDowell has publicly noted that no major spacecraft or orbiting rocket body re-entered at this time. One other possibility is that the aircraft may have been hit by debris from a missile test. However, there is no evidence reported for this.