Mission Operations Center staff watched with excitement as a dot on the screen gradually expanded into an unmistakably spherical, boulder-covered space rock. Engineers quickly announced “this is nominal”, an aerospace engineering term meaning everything had gone as planned.
DART was built for this momentous occasion – to demonstrate technology that could one day shield Earth from asteroids impacting it. Yet DART taught us more than that this week.
Why do spacecraft crash?
There are various reasons for spacecraft crashes. Miscalculation is probably the primary factor, with something such as micrometeorites puncturing through thrusters to alter exhaust direction slightly, or sensors malfunctioning and making the spacecraft think it has run out of fuel prematurely causing it to crash.
Another challenge facing satellites in low Earth orbit is their tendency to fall back toward Earth over time. Although fueling your satellite will keep it orbiting for longer, that process is expensive and time consuming.
Finding an orbit for a defunct satellite to travel without falling back down is quite an uphill battle, contrary to popular sci-fi depictions. A minor miscalculation could easily send it hurtling towards the sun; but in reality it takes much energy and focus just to break free from Earth’s gravity and get off this planet’s gravity entirely. Thus most satellites end up falling back down instead of trying to travel off into space when their lives end.
What causes a spacecraft to crash?
Spacecraft are expensive and energy intensive to launch into orbit, and no one wants their efforts to collide. Unfortunately, accidents do happen and with more satellites and probes active near Earth orbit than ever, crashes have become increasingly likely – littering our celestial road with debris.
The primary source of trouble on board ships is often related to one or more of its systems: possibly cryosleep coolant, reactor fuel or engine fuel tank ruptures and spills its contents out into space; or it could be that computer has reached “outside parameters”, telling crewmembers instead to land on planet D instead of planet A (although that could also be deliberate – like part of an intentional plot point).
Micrometeorites hit thrusters, changing their direction slightly. Or perhaps an incorrect sensor reading has led the ship to believe it has run out of fuel when in actuality it still has more to go.
What happens if a spacecraft crashes?
Spacecraft could crash into planets in numerous ways: its massive kinetic energy could cause its destruction; or it may hit a space station or satellite and trigger an orbital debris storm, endangering all space environments; it may also hit Earth with enough force to cause earthquakes, tsunamis or volcanic activity.
Samson recognizes this possibility is unlikely, yet as more nations, institutions, and companies launch objects into space, its risks increase exponentially. For that reason, she suggests formal crash avoidance coordination as well as increased transparency and collaboration across national borders.
An improved understanding of who owns and operates what’s up there would help ensure we have more certainty around liability when something like the stanchion that struck Otero’s house in Naples comes hurtling down from space. An effective space law could deter actors from polluting space environments by holding them accountable, decreasing their likelihood of doing so and making Otero less likely to encounter harm as a result of doing so.
What happens if a spacecraft crashes on a planet?
At best, celestial bodies of certain sizes will harmlessly reenter Earth’s atmosphere and burn up. At worst, however, they could create an unsafe cloud of debris that endangers other satellites in low Earth orbit and render space virtually unusable.
European Space Agency (ESA) provided live updates as the ERS-2 raced towards Earth, providing air density and weather patterns data that allowed it to predict when and where its landing would occur. Reentry proved surprisingly controlled.
As ESA’s spacecraft descended, it slammed into an asteroid named Didymos – not to destroy but instead alter its future path. It wasn’t the first intentional collision; NASA’s LCROSS mission performed a similar experiment in 2009 by deliberately striking up with lunar craters to generate seismic data on our Moon and send a projectile crashing through one to generate seismic readings as well as provide clues as to where exactly on the craft were impact. The impact site will provide scientists insights as well as clues as to where its creators intended it before impact.