There was a protracted delay between Flight 52 and Flight 53, and a deviation from the printed Flight 53 plan. I’ll deal with each on this weblog submit. First, the Flight 53 delay was the direct results of a call by the workforce to fly Ingenuity out of telecom communications vary with the rover. One could query the knowledge of this, however there are good causes to take action.
When plotting a traversal path via a given space, the workforce identifies a sequence of clean, flat areas known as “lily pads” the place the helicopter can safely land with out important danger of injury to the automobile. As a result of the helicopter’s laser altimeter is pretty delicate to giant terrain variations, the workforce additionally typically tries to plan flight paths over the smoothest and flattest terrain accessible. These terrain varieties additionally occur to be the areas favored by rover planners as they’re extra simply traversable and include fewer obstacles which may impede rover progress. The result’s that in tough terrain, the 2 autos typically compete for a similar slender path.
Roughly talking, the Ingenuity workforce’s high mission priorities are:
1 – Keep away from important interference with, or delay of, rover operations
2 – Preserve automobile well being and security
3 – Carry out scouting for tactical planning and science evaluation
4 – Carry out experiments to tell mission and automobile design for future Mars rotorcraft, or gather knowledge for discretionary science
In tough terrain, the primary two priorities end in an emphasis on staying nicely forward of Perseverance. Staying solely barely forward of the rover whereas offering good knowledge switch charges is dangerous because the helicopter could inadvertently block the rover’s path. Staying simply behind the rover can be a problem, because the flight paths of the helicopter would have to be too near the rover for security or incorporate energy-sapping diverts to keep up ample distance. Staying to the facet of the rover is usually not potential as a consequence of communications and landing-site constraints. Staying far behind the rover clearly dangers lack of telecom, which might pressure the rover to reverse (violating precedence #1) or go away the helicopter behind (violating precedence #2). Thus, the helicopter often operates in a slender slice of terrain a number of hundred meters forward of the rover’s place. When telecom permits, the workforce will attempt to land at places parallel to Perseverance’s deliberate strategic route, however this has been the exception, not the rule during the last yr of the mission.
This balancing act require cautious planning to maximise operational flexibility, agile replanning of flights/actions on quick discover, and a excessive variety of operations shifts specializing in file transfers to compensate for the poor knowledge switch speeds on the fringes of the radio’s vary. Gradual knowledge switch turnaround reduces the achievable flight cadence and operational effectiveness of the helicopter.
Flying barely forward of telecom vary is one technique to deal with this setting, because it buys time, decreasing the chance of rover interference and/or decreasing the demand on the operations workforce to execute short-notice flights. This, nevertheless, has some drawbacks: 1) It additional retards operation cadence, because it forces the helicopter to spend extra time in areas with poor telecom. 2) It may possibly probably strand the helicopter past comms vary if the rover encounters any delay or makes tactical choices that deviate from the strategic route. This latter vulnerability got here into play nearly instantly after Ingenuity executed its 52nd flight.
A Ready Sport
Flight 52 was deliberate as a long-distance, out-of-telecom flight, which was executed on Sol 776 with the expectation that the rover was nearing the tip of its exploration at Echo Creek and could be approaching the helicopter’s resting spot close to Mt. Julian inside just a few sols. The flight was carried out precisely as deliberate, with Ingenuity dropping radio hyperlink at roughly 8 meters (matching our telecom fashions). Nonetheless, the shortage of profitable touchdown affirmation meant that the downlinked telemetry for this flight was considerably much less reassuring than typical post-flight downlinks. The workforce settled in for what was speculated to be a quick however suspenseful watch for Perseverance to catch up and supply affirmation that the intrepid helicopter had landed safely.
Roughly per week later, the rover started shifting, however as an alternative of heading southeast towards Mt. Julian as deliberate, the science workforce had determined to carry out an investigation of the world round Powell Peak. The Ingenuity workforce members, grateful for the unplanned break however nonetheless worrying in regards to the unknown state of the helicopter, ready for one more week or two of ready. Weeks quickly become months because the rover overcame varied challenges to its schedule. The poor structural integrity of the rock within the space foiled two sampling makes an attempt earlier than the rover workforce was capable of efficiently seize a pattern on Sol 822 and efficiently seal it 10 sols later. Individuals following the rover’s actions will know that this marketing campaign proved to be far tougher than anybody imagined. Lastly, after one other week of actions, Perseverance was shut sufficient to re-establish communications with Ingenuity on Sol 837.
In complete, Ingenuity had been out of contact for 61 sols, an eternity when the result of the flight was unknown to the workforce. This marked the longest interval of helicopter inactivity since Perseverance and Ingenuity landed on the planet. Throughout this time, the Ingenuity workforce had largely deactivated, with members reallocating their time to work on different tasks.
Because the workforce dusted off the cobwebs and began bringing down log recordsdata and pictures from the flight, it turned obvious that the helicopter had spent the final two months parked on one thing really outstanding. Sitting immediately beneath Ingenuity’s ft, unfold over the fractured rock of the riverbed, was a set of cobbles and pebbles not like any that scientists had seen earlier than. Many have been partially eroded and exhibited a vesicular texture extra paying homage to recent basalt. These rocks instantly garnered a robust response from venture scientists, who requested that Ingenuity carry out a devoted science scouting flight as quickly as potential.
The Science Flight That Wasn’t
The workforce jumped on the uncommon alternative to supply precious and thrilling superior science reconnaissance, however the flight would finally pan out in a really totally different manner. Flight 53 was to be an especially fascinating flight with in depth RTE (colour digital camera) imagery at low altitude to return a plethora high-resolution floor scans overlaying parts of the riverbed barely north of the unique touchdown location. Partway via the flight on Sol 864, nevertheless, a synchronization challenge with the time-critical navigation digital camera triggered the “LAND-NOW” fault safety routine within the steerage navigation and management (GNC) subsystem. Because the title implies, this precipitated Ingenuity to abort the flight and land instantly the place it was.
Ingenuity corrects its spatial orientation estimate by monitoring the motion of floor options inside these navcam photographs, however these knowledge have to be completely time-synchronized with measurements from the inertial steerage system to supply legitimate corrections. Within the case of Flight 53, this synchronization step mysteriously failed in a manner that hadn’t been noticed on any of the prior 52 flights on Mars or through the years of floor testing that preceded them. As of this writing, the exact trigger is strongly suspected however has not been conclusively confirmed.
In the course of the growth section of the mission, many fault responses have been thought-about, however with a system as inherently unstable and time delicate as a helicopter, the very best response is nearly at all times to land as quickly as potential. Following the R8.0 software program replace in October of 2022, the fault response had been subtly modified. R8.0 included a brand new and precious hazard-divert functionality, permitting the helicopter to intelligently shift its touchdown goal to keep away from areas that appeared harmful to its cameras. This replace additionally utilized the hazard-divert habits to the LAND-NOW response. In what was absolutely a lucky coincidence, the GNC workforce had found a peculiar and probably deadly interplay between these two behaviors only one month previous to flight. By the point of Flight 53, operational modifications had been put in place mitigate the difficulty (stopping using hazard-diverts throughout emergency landings). The Flight 53 LAND-NOW executed exactly as designed, getting the helicopter on the bottom shortly and safely. This occasion was unprecedented and is Ingenuity’s first emergency touchdown on Mars.
By the point the workforce had assessed the difficulty, Perseverance had caught as much as the helicopter and handed it on Sol 871, eradicating the necessity to full the imaging deliberate for Flight 53. Ingenuity returned to the skies of Mars with a brief pop-up Flight 54 to get a repair on its location after which resumed its scouting duties at a brand new location with Flight 55 on Sol 881.
Parting Ideas
The workforce is in a continuing battle with minimizing and balancing varied dangers. Ingenuity was flown out of comms vary to protect in opposition to the very probably risk that venture scientists would decide to go west instantly. This illustrates the issue in making efficient plans when the flexibility to execute these plans is solely depending on one other automobile, itself topic to sudden occasions. That is doubly true because the science mandate of Perseverance rightly dictates that its plans ought to change as new discoveries are made and new knowledge grow to be accessible. Even with out these inherent coordination challenges, generally sudden occasions can derail even probably the most well-laid plans as they did in Flight 53. Nobody on the venture may have predicted the eventual end result that resulted within the lack of two months of helicopter mission time and the unlucky lack of one of the thrilling scouting flights in current reminiscence. However, the helicopter will proceed up the traditional river delta, balancing dangers and offering scouting for the rover the place potential. The 2 Mars autos will quickly attain an space the place the rover is scheduled to loiter for a number of months. This could considerably loosen up planning constraints and supply a chance for the helicopter to interact in a greater variety of actions.
