Did you know…
Did you know… Questions and answers about aviation and space
The most searched questions about planes, rockets, pilots and astronauts, answered in two lines and explained in depth, with sources.
Aviation
Commercial aviation
How much does the a320 cost?
Airbus stopped publishing list prices in 2018. In that final catalogue the A320neo was $110.6 million, the outgoing A320ceo $101.0 million and the A321neo… more…
Physics of flight
Why do supersonic planes have swept wings?
Sweep delays and softens the drag rise around the speed of sound. Only the airflow component perpendicular to the leading edge counts for compressibility, so… more…
Military aviation
Why was the sr 71 blackbird decommissioned?
The SR-71 was retired in 1990 because the Air Force judged it too expensive to keep flying, at hundreds of millions of dollars a year, when satellites and… more…
Physics of flight
How much the speed of sound?
In air at 20 °C the speed of sound is about 343 m/s, or 1,235 km/h (767 mph, 667 kn). It depends on temperature, not pressure: in the standard atmosphere it… more…
Physics of flight
How does the speed of sound change with altitude?
The speed of sound depends only on air temperature, not on pressure or density, so it falls as the troposphere cools: about 340 m/s (661 kn) at sea level in… more…
Military aviation
Why is the rafale so expensive?
The Rafale is expensive because France developed it alone, without partners to share more than €40 billion of development cost, builds it at a low rate of two… more…
Space
Rockets and launches
How does starship land?
Starship lands propulsively. The Super Heavy booster flies back, slows with a landing burn and is caught in the air by the arms of the launch tower, first… more…
Rockets and launches
Why is falcon 9 launching?
Falcon 9 launches so often because it is the workhorse of SpaceX's own Starlink network: about two thirds of its flights carry Starlink satellites, several… more…
Rockets and launches
Why does a rocket curve?
A rocket curves because orbit is a matter of sideways speed, about 7.8 km/s for low Earth orbit, not of altitude. It rises vertically only long enough to… more…
Rockets and launches
Why did a rocket launch today?
Rockets launch almost daily: in 2025 there were roughly 300 orbital launch attempts worldwide, more than half of them by SpaceX, so a launch on any given day… more…
Rockets and launches
Why does starship explode when it hits the water?
Starship explodes on splashdown because the test flights are designed to end at sea, where the vehicle is not recovered. When it touches the water it tips… more…
Rockets and launches
How much did the space race cost?
The American side is documented: Project Apollo cost about 25.4 billion dollars as reported to Congress in 1973, roughly 257 billion in 2020 dollars, with… more…