Flying has never been a safe or precise art. Even when it is not on Mars! Latest from the Ingenuity saga, from NASA it's own self.
On the 91st Martian day, or sol, of NASA's Mars 2020 Perseverance rover mission, the Ingenuity Mars Helicopter performed its sixth flight. The flight was designed to expand the flight envelope and demonstrate aerial-imaging capabilities by taking stereo images of a region of interest to the west. Ingenuity was commanded to climb to an altitude of 33 feet (10 meters) before translating 492 feet (150 meters) to the southwest at a ground speed of 9 mph (4 meters per second). At that point, it was to translate 49 feet (15 meters) to the south while taking images toward the west, then fly another 164 feet (50 meters) northeast and land.
Telemetry from Flight Six shows that the first 150-meter leg of the flight went off without a hitch. But toward the end of that leg, something happened: Ingenuity began adjusting its velocity and tilting back and forth in an oscillating pattern. This behavior persisted throughout the rest of the flight. Prior to landing safely, onboard sensors indicated the rotorcraft encountered roll and pitch excursions of more than 20 degrees, large control inputs, and spikes in power consumption.
[...] Approximately 54 seconds into the flight, a glitch occurred in the pipeline of images being delivered by the navigation camera. This glitch caused a single image to be lost, but more importantly, it resulted in all later navigation images being delivered with inaccurate timestamps. From this point on, each time the navigation algorithm performed a correction based on a navigation image, it was operating on the basis of incorrect information about when the image was taken. The resulting inconsistencies significantly degraded the information used to fly the helicopter, leading to estimates being constantly "corrected" to account for phantom errors. Large oscillations ensued.
Large oscillations are better than small ones, if the truth be told. Godspeed, Ingenuity!
(Score: 3, Informative) by mhajicek on Friday May 28 2021, @03:48PM (3 children)
Translation is lateral movement.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by driverless on Saturday May 29 2021, @11:41AM (1 child)
It's not just that, the use of "excursions" when describing failure modes like this is also quite novel. My favourite is when a reactor is described as having undergone a power excursion. That doesn't mean a day trip to the zoo, it means Chernobyl.
(Score: 2) by Immerman on Sunday May 30 2021, @03:19AM
Novel? Translation is the standard term for movement along an axis in math, physics, and engineering - to clearly distinguish from rotation, the other kind of (common) motion with respect to the same axes.
As for excursion, it's the second definition in Merriam-Webster:
When professionals in a field discuss something, they're likely to use the common technical terms for whatever they're discussing. Using layman's terms typically means they'd have to use twice as many words to say the same thing less accurately.
(Score: 3, Insightful) by Immerman on Sunday May 30 2021, @03:12AM
In more detail...
Not just lateral (=side-to-side), but also vertical and front-to-back.
Basically there's six distinct kinds of motion a rigid body can potentially undergo - hence "6-axis" or "6DOF" (degrees of freedom) when talking about VR controllers, robots, etc.
You can spin *around* any axis (yaw, pitch, and roll) = rotation
You can move *along* any axis = translation
Those are the standard terms used in math, physics, and engineering to specify the exact kind of motion being discussed. If you're talking about non-rigid bodies then you also introduce stretch, skew, bending, etc. Way more degrees of freedom, but both the math and engineering gets a lot more complicated as a result, so we mostly design things to be as rigid as possible to simplify the analysis.