Min Of Flight Research Articles

Supersonic Waves Generated by the 18 November 2023 Starship Flight and Explosions: Unexpected Northward Propagation and a Man‐Made Non‐chemical Depletion

AbstractOn 18 November 2023, SpaceX launched the Starship, the tallest and the most powerful rocket ever built. The Super Heavy engine separated from the Starship spacecraft and exploded at 90 km of altitude, while the main core Starship continued to rise up to 149 km and exploded after ∼8 min of flight. In this work, we used data from ground‐based GNSS receivers and we analyzed total electron content (TEC) response to the Starship flight and the two explosions. For the first time, we observed large‐distance northward propagation of intensive 2,000 km V‐shaped ionospheric disturbances from the rocket trajectory. The observed perturbations, most likely, represent shock waves propagating with the cone angle of ∼14° on the North and ∼7° on the South against the flight track that corresponds to the Mach angle of the shock waves in the lower atmosphere. The Starship explosion also produced a non‐chemical depletion in the ionospheric TEC.

Behavioural and physiological responses of captive Antillean manatees to small aerial drones

Abstract Context Unmanned aerial vehicles or drones are powerful tools for wildlife research. Identifying the impacts of these systems on target species during operations is essential to reduce risks of disturbance to wildlife, to minimise bias in behavioural data, and to establish better practices for their use. Aims We evaluated the responses of captive Antillean manatees to the overhead flight of a small aerial drone. Methods We used aerial and ground videos to compare manatee activity budgets and respiration rates in three 15-min sampling periods: ‘before’, ‘during’ and ‘after’ flights with a DJI Phantom 3 Advanced. The drone was hovered stationary for 3 min at five altitudes (100 m, 40 m, 20 m, 10 m, 5 m) to determine whether manatees display behavioural responses compared with the control period, and whether they respond more at lower altitudes. Only one flight was performed per manatee group to avoid bias owing to habituation to the drone. Key results Manatees responded to drone flights by (1) increasing their activity levels during and after flights, therefore signalling after effects; (2) decreasing their respiration rate during flights; and (3) displaying behavioural reactions including grouping, tail-kicking, fleeing from their original position and moving under submerged structures. From the 11 individuals displaying behavioral reactions, 9 reacted in the first ~2 min of flight, preventing assessments of altitude effects and suggesting manatees responded to the drone sound at take-off. Conclusions Behavioural changes of responding manatees were similar to previous reports of disturbance responses to boats and drones in this species. Our use of a control period showed shifts in respiration rates and activity budgets that persisted after flights. Several manatees reacted to the drone from the time of take-off and first minutes of flight, indicating that the sound of the electric rotors could be a strong negative stimulus to manatee and highlighting the importance of establishing safe distances for take-off. Implications Future studies should consider that drones could elicit conspicuous and inconspicuous responses in manatees. Our results emphasise the need for control data on animal behaviour to better assess the impact of drones on wildlife and to design non-invasive protocols.

The effect of transportation suit induced heat stress on helicopter underwater escape preparation and task performance

Although essential in an emergency such as a helicopter ditching, mandatory survival suits worn by civilian personnel may lead to heat strain during a normal flight. To explore the possibility that wearing a helicopter transportation suit impairs emergency performance, 11 individuals completed underwater escape procedures immediately following a pre-recorded emergency announcement (randomly played between 50 and 90 min) in two ambient temperature conditions (Thermoneutral = 21 °C and Hot = 34 °C). Mean skin and rectal temperatures were recorded throughout the trials, while situation awareness and thermal sensation/comfort were recorded on completion of trials. Results indicate that although mean skin and rectal temperatures were significantly higher at the end of both trials, escape procedures were not impaired. It can therefore be concluded that although conditions inside an offshore transport helicopter are perceived as being hot and uncomfortable, no deficits in escape performance should be expected in the first 90 min of flight.

Using Automated Flight Mills to Manipulate Fat Reserves in Douglas-fir Beetles (Coleoptera: Curculionidae)

Because current techniques for quantifying fat, the main fuel used for flight in insects, are destructive, researchers are limited to only one direct measure of fat per specimen. This limitation is problematic for studies aimed at assessing whether fat loss through flight influences subsequent behavioral activity. To overcome this problem, we used body volume, body mass, emergence day, and brood density as parameters in a multiple regression model to predict initial fat levels in female Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, on emergence from the host. The model explained 54% of the variation in fat reserves as determined by Soxhlet extraction with petroleum ether. Treatments of 30-1,380 min of flight on rotary flight mills were used to establish the relationship between flight and fat reserves. Using a model that incorporated estimated initial fat levels, as well as time spent in flight and time in nonflight activities on the flight mills, we found that 6 h of flight decreased fat by approximately 50%. Flight activity and nonflight activity did not differ significantly in terms of their effect on fat reserves. Individual beetles with high initial fat content flew longer and faster on flight mills than beetles with low initial fat reserves. Our study shows how researchers can manipulate fat levels in bark beetles and other insects through flight, thereby opening the door to using these manipulations in behavioral studies.

Endocrine control of TAG lipase in the fat body of the migratory locust, Locusta migratoria

Aspects of the role and activation of the enzyme triacylglycerol lipase (TAG lipase) in the fat body of the migratory locust Locusta migratoria were investigated. TAG lipase is under the hormonal control of the three endogenous adipokinetic peptides of the migratory locust, Locmi-AKH-I, Locmi-AKH-II and Locmi-AKH-III. Injection of low doses (5–10 pmol) of each peptide causes an increase in lipase activity. The activation of lipase is time dependent: an elevated activity was recorded 15 min after injection of 10 pmol Locmi-AKH-I and maximum activation was reached after 45–60 min. The activation of TAG lipase is also dose-dependent. Doses of 2 pmol of each Locmi-AKH had no effect, whereas 5 pmol caused a significant activation. Maximum activation is reached with a dose of 10 pmol. Analogues of the second messengers cAMP (cpt-cAMP) and IP 3 (F-IP 3) both activate the enzyme glycogen phosphorylase whereas only cpt-cAMP, but not F-IP 3, activates TAG lipase; cpt-cAMP elevates the lipid levels in the haemolymph. Activation of lipase is specific to the three endogenous AKH peptides: 5 pmol of the endogenous peptide Locmi-HrTH and 10 pmol of corazonin failed to activate lipase. High doses of octopamine did not activate lipase nor did they elevate the lipid concentration in the haemolymph. TAG lipase is stimulated by flight activity but activation is slower than that of glycogen phosphorylase: after 30 min of flight or after 5 min of flight plus 1 h of subsequent rest, activity of TAG lipase is increased, but not immediately after 5 min of flight. In contrast, glycogen phosphorylase is activated significantly after 5 min of flight. These activation patterns of the two enzymes mirror-image the concentration of their substrates in the haemolymph: there is a significant decrease in the concentration of carbohydrates after 5 min of flight, whereas no change of the concentration of lipids can be measured after such short time of flight activity; however, a subsequent rest period of 1 h is sufficient to increase the lipid concentration.

Utilisation of substrates during tethered flight with and without lift generation in the African fruit beetle Pachnoda sinuata (Cetoniinae).

We have investigated the pattern of metabolic changes during tethered flight with and without lift generation in the African fruit beetle Pachnoda sinuata. Two distinct metabolic phases occur during lift-generating flight. The first phase is characterised by a high rate of oxygen consumption and a rapid change in proline and alanine levels in the haemolymph and flight muscles and in glycogen level in the flight muscles. Carbohydrates are released from the fat body into the haemolymph. These carbohydrates are oxidised during the second phase. Changes in proline and alanine levels in the haemolymph and flight muscles and in glycogen level in the flight muscles are minor during the second phase and the rate of oxygen consumption is reduced. During lift-generating flight, metabolic changes are rapid. Proline concentrations in the haemolymph and flight muscles fall dramatically during the first 30 s of flight, while alanine concentrations rise concomitantly. While haemolymph concentrations of proline and alanine remain virtually unchanged thereafter, further changes in the levels of these amino acids occur in the flight muscles during 5 min of flight. The initial levels of the two amino acids in the flight muscles are re-established over 1 h of rest following a 5 min flight, while this process takes longer in the haemolymph. The concentration of haemolymph carbohydrates increases during the first 30 s of flight and declines thereafter during 5 min of flight. The pre-flight levels are restored after 1 h of subsequent rest. The stores of glycogen in the flight muscles are rapidly diminished during the first 10 s of flight and decrease at a lower rate during further flight lasting up to 5 min. A subsequent 1 h of rest is sufficient almost to restore pre-flight levels. Haemolymph lipid levels are slightly but significantly increased during 11 min of flight and after 1 h of subsequent rest. During flight without lift production, the metabolic changes are considerably slower and beetles fly approximately seven times longer than during lift-generating flight. Resting basalar (BM), dorso-ventral (DVM) and dorso-longitudinal (DLM) flight muscles show no differences in levels of proline, alanine and glycogen. After different periods of flight, during which lift and wing loading were minimised, the DVM was found to have the highest level of proline after 5 min of flight. Levels of alanine in the DVM were lower than in the DLM. There was no evidence to suggest that different flight muscles are specialised for either proline or carbohydrate utilisation. Proline and carbohydrates participate equally in supplying energy to the flight muscles during lift-generating flight. The contribution to the energy supply by the flight muscles is 54 %, while that of the haemolymph is 46 %.

More g's than the Space Shuttle: ballistospore discharge

Ballistospores of basidiomycete fungi form at the tips of spear-shaped projections called sterigmata that extend from basidia. At maturity, a spherical drop of fluid appears at the base of each spore, and a few seconds later the spore is propelled into the surrounding air. The development of the fluid drop was first reported in 1889, but a century of innovative research was necessary to solve the mechanistic link between the drop and spore discharge. Through an extraordinary series of experiments the composition of the drop has now been established, its development is explained, and an effective solution to the relationship between drop appearance and spore discharge has been proposed. Drop formation is initiated when a femtomole quantity of mannitol and hexoses is excreted from a specific site at the base of the spore, forming a hygroscopic nucleus upon which water condenses from the surrounding air. Discharge of the spore occurs when the drop fuses with a film of liquid that curves over the adjacent spore surface. This rapid coalescence results in a decrease in surface free energy within the liquid and displaces the center of mass of the spore. The change in weight distribution exerts a force that is opposed by the pressurized sterigma, and the spore is shot away from the basidium into the surrounding air. The mechanism is described as a surface-tension catapult. During discharge, ballistospores are subjected to an acceleration of 25 000 g, which is about ten thousand times the acceleration experienced by astronauts during the launch of the Space Shuttle! Even more impressive is the fact that while the Shuttle consumes 50% of its weight in fuel in the first 2 min of flight, ballistospore discharge is fueled by the mannitol and hexoses that cause water to condense on the spore surface, and these solutes represent only 1% of the mass of the spore.

Evidence for volatile chemical attractants in the beetleMaladera matrida argaman (Coleoptera: Scarabaeidae)

TheMaladera matrida beetle (Coleoptera, Scarabaeidae, Melolonthinae), a relatively new species to science, was first identified in Israel in 1983. In the course of field observations it was found that adultM. matrida beetles emerged from the soil at sunset to feed and mate. During the first 20 min of flight, most of the beetles were males. The females emerged shortly afterwards, and aggregations numbering 20-30 individuals with equal proportions of males and females were eventually formed on peanut plants. Laboratory olfactometer bioassays showed that peanut leaves (food) attracted both males and females. Field-trapping experiments and olfactometer studies showed thatM. matrida beetles were highly attracted by live virgin females in the presence of food (cut-up peanut leaves). Another set of field trapping experiments indicated that airborne volatiles produced by live virgin females plus food had the same attracting ability as live virgin females plus food. The attraction exerted by the combination of live virgin females and peanut leave volatiles suggests a synergism effect. Accordingly, we propose a two-stage mechanism of chemical communication in theM. matrida beetles: first, the males cause mechanical damage to the host plant to attract both sexes; later, the females emit attractants (sex pheromone) while eating or shortly thereafter.

Regulation of carbohydrate metabolism during flight in Manduca sexta

During the first 5 min of flight in Manduca sexta haemolymph carbohydrate levels decrease by about 8 mg × ml −1 or at a rate of at least 350 μg × min −1 and thereafter they remain more or less unchanged. Before flight about 7% of total fat body glycogen phosphorylase is in the active form, while after 30–60 min about 35% is found in the active form. Even after 1 h of flight, the increased mobilization of carbohydrates by active glycogen phosphorylase can only account for 11–25% of the rate a which carbohydrates are used at the start of flight. The activity of fat body glycogen phosphorylase is not controlled by hormones from the corpora cardiaca. The adipokinetic hormone from these glands does not, therefore, control the activity of glycogen phosphorylase during flight although, it is secreted during flight, and if corpora cardiaca extracts are injected they can activate glycogen phosphorylase. It is suggested that the decrease of haemolymph carbohydrates may control the activation of fat body glycogen phosphorylase.

The effect of flight on the composition of haemolymph in the cockroach, Periplaneta americana

The composition of the haemolymph in Periplaneta americana is markedly altered during the 6 h following a 10-min flight. Normal resting conditions are not re-established for at least 24 h. The haemolymph volume increases 30% between 1 and 6 h after flight while the concentration of Na +, remains constant. Within 2 min after the beginning of flight there is a significant increase in the concentration of K + followed by an increase in Ca 2+ and Mg 2+ at the time flight is terminated. The increase in volume of the haemolymph is accompanied by a 25% decrease in osmolarity. Twenty-four hours after flight both haemolymph volume and osmolarity are re-established at the pre-flight values. During the return of fluid volume and osmolarity to normal levels, the ion concentrations, with the possible exception of Na +, are kept constant. The concentration of trehalose increases 10% during the first 2 min of flight, then decreases to the resting level within 5 min after flight ceases. Twenty minutes after flight the concentration of trehalose rises again, to 35% above the resting level where it remains for at least a day. At 1 day after flight the total trehalose in the haemolymph pool has returned nearly to the pre-flight level.

Flight and settling behaviour ofRhopalosiphum Padi(L.) (Hemiptera: Aphididae)

AbstractAlate exules ofRhopalosiphum padi(L.) were flown in a flight chamber for three different flight times: 1 min, 5 min and 25 min. The rate of climb was recorded continuously during flight. Afterwards, the aphids were forced to land on either wheat or potato and settling behaviour was recorded. The settling response was strengthened with increasing flight time on both plants. The aphids spent more time walking and made more probes on potato than on wheat after 25 min of flight. The rate of climb was the same immediately before landing as immediately after a spontaneous re-take-off, except after a 25-min flight and landing on potato when the rate of climb was significantly higher after re-take-off. Comparison withAphis fabaeScop. from other investigations showed that the change in settling response with flight time was similar for the two species.R. padiseemed less able to discriminate rapidly between host and non-host plants thanA. fabae. It is concluded that its behaviour does not hinderR. padifrom being a vector of stylet-borne potato viruses.

Temperature Regulation and Heat Balance in Flying White-necked Ravens, Corvus Cryptoleucus

ABSTRACT During level flight at 10 m.s−1 in a wind tunnel, white-necked ravens (Corvus cryptoleucus, mass 0·48 kg) exhibited an increase in body temperature to steady-state levels as high as 45 °C, exceeding resting levels by nearly 3 °C. This reflects the storage of up to half of the metabolic heat produced (Hp) during 5 min of flight. During steady-state flight, body heat was dissipated in part by respiratory evaporation and convection (13–40% of Hp) evoked by increases in ventilation proportional to body temperature. Remaining heat was lost by cutaneous evaporation (10 % of Hp) as well as by radiation and convection from the external body surface. The results suggest strategies that might be used by ravens during flight under desert conditions.

Carbohydrate utilization in the thoraces of honey bees ( Apis mellifera) during early times of flight

Trehalose levels in the thoraces of honey bees did not change significantly during the first 2–4 min of flight. This effect was seen both for bees flown shortly after removal from the hive and for bees which were flown after a 2 hr starvation period. There was also no detectable activation of the trehalose in isolated mitochondria from bees flown for periods of up to 2 min. However, the glucose content of the thoraces of bees flown shortly after removal from the hive dropped dramatically during the first 15 sec of flight. There was no evidence of a transient increase in the glucose content in the thorax at any of the times studied as would be expected if trehalose were hydrolized. The drop in glucose content at early times of flight was not detected if the bees were starved for 2 hr before flight was started. The changes in fructose content of the thoraces with time were similar to those observed for glucose, but were not statistically significant due to variation among individual bees. The sucrose content of bee thoraces varied greatly and no meaningful conclusions could be reached about how it changed as a function of time of flight.

Respiratory and Cardiovascular Responses of the Pigeon to Sustained, Level Flight in A Wind-Tunnel

ABSTRACT Five pigeons were trained to fly in a boundary-layer wind-tunnel at a velocity of 10 m s−1 for at least 10 min, and a number of respiratory and cardiovascular variables were recorded. For comparison, heart rate, respiratory frequency and E.M.G. from the pectoralis major muscles were also recorded, using radio-telemetry, from free-flying pigeons. For the flights in the wind tunnel there were immediate increases in respiratory frequency and heart rate upon take-off; these variables continued to increase during the flight, eventually becoming on average 411 breaths min−1 (20 × resting) and 670 beats min-1 (6 × resting) respectively. There was a 1:1 relationship between ventilation and wing beat. Oxygen uptake and carbon dioxide production reached their highest values of 12·5 × and 14·4 × resting respectively within 1 min of take-off and then declined to steady levels of 200 ml kg−1 min S.T.P.D. (1O × resting) and 184 ml kg−1 min S.T.P.D. (10·7 × resting) 4 min after take-off. If allowances are made for the weight and drag of the mask and tubes, these stable values are at least 12 % higher than would occur in an unloaded bird. Body temperature rose steadily after take-off, reaching a stable value of 43·3 °C, which was 2 °C above resting, after 6 min of flight. There was a 1·8 × rise in content difference and little change in cardiac stroke volume during night, so that the rise in heart rate was the major factor in transporting the extra O2 to the active muscles. Respiratory quotient rose from 0·85 at rest to 0·99, 30 s after take off, and then fell to 0·92 after 7 min of flight. Blood lactate rose to 59·8 mg% (6·5 × its resting value). Comparisons with the free-flying birds indicated that the pattern of flight in the wind tunnel was somewhat abnormal, especially at the beginning of a flight, and this may account for the value of being higher at the start of a flight and then declining to a steady value as the flight progressed. Upon landing, heart rate, and body temperature began to fall immediately, and within 2 min, heart rate, and had returned to the ‘tunnel on’ resting values. Respiratory frequency increased upon landing and its decline closely matched the fall in body temperature. R.Q. rose above unity immediately upon landing as CO2 was removed in excess of its metabolic production, and then fell below the resting value as CO2 was retained, presumably to maintain acid/base balance during the metabolism of lactic acid.

Body temperature and flight performance of honey bees in a servo-mechanically controlled wind tunnel

1. Workers ofApis mellifera ligustica were tethered to an aerodynamic balance in front of a laminar wind tunnel. They had control over the tunnels wind velocity. Lift, wind speed, wingbeat frequency, thorax and air temperature, and the action potentials in the fibrillar dorsoventral (DV) and dorsolongitudinal (DL) flight muscles were continuously recorded. The air temperature in the tunnel could be controlled. Correlations between all mentioned parameters and the thorax temperature were analyzed. 2. Animals that assumed flight position and flew for more than thirty seconds disregarded optical inputs. They did not respond to changes in speed or direction of an optical pattern, and flew even in complete darkness. 3. In flights that started with thorax temperatures at environmental values, temperature differences between thorax and environment reached 5.2 °C after 4. 5 min of flight (Fig. 1). In animals with body temperatures above 36 °C, active temperature regulation could be observed: A large drop of fluid appeared between the ventral side of the head and the thorax, and the front legs frequently rubbed the fluid over the ventral part of the thorax. 4. The average wingbeat frequency showed a linear increase from 136 Hz at a thorax temperature of 24 °C, to 194 Hz at thorax temperature of 33.5 °C. A further increase of the thorax temperature from 33.5 °C to 38 °C was correlated to an increase of the wingbeat frequency to 202 Hz. This increase had a much smaller slope (Fig. 2). 5. The average lift increased from 28.5 dynes at 24 °C to 78.5 dynes at 33 °C (body angle 0°). The lift stayed practically constant from 33 °C to 38 °C (Fig. 2). The lift at thorax temperatures between 33 °C and 38 °C would keep the empty body weight aloft. The flight velocity increased from 0.8 m/sec, thorax temperature at 24 °C, to 3.3 m/sec, thorax temperature at 38 °C (Fig. 2). 6. The average action potential frequencies (APF) in the fibrillar flight muscles rose from between 8 and 9 Hz at thorax temperatures of 24 °C to between 12 and 13 Hz at thorax temperatures of 38 °C. In the range of biggest change in lift and thrust, at thorax temperatures between 26 °C and 31 °C, the APF in the dorsoventral muscles stayed constant, while it rose only one Hz in the dorsolongitudinal muscles (Fig. 2). 7. The increase in lift showed a linear relationship to the increase in wingbeat frequencies between 122 Hz and 158 Hz. Between 158 Hz and 208 Hz the gain in lift was bigger. From 208 Hz on the lift stayed constant. The flight velocity rose linearily with wingbeat frequencies from 122 Hz to 208 Hz (with some irregularities near 140 Hz) and with a steeper increase at wingbeat frequencies over 208 Hz (Fig. 3). 8. It was concluded that the large increase in the power output of the flight motor that occurred with rising thorax temperatures was mostly caused by an augmentation of the efficiency of the flight system and not by an increase in neural activation.

The utilization of trehalose during flight by the housefly, Musca domestica

The male housefly, Musca domestica, utilizes trehalose during flight. However, the rate of utilization of treahlose is most rapid during the first few minutes of continuous flight (i.e. during the first 5 min of flight, the rate of utilization of trehalose is 187 μg/thorax per hr; this results in a thoracic trehalose level of one-third of that of the unflown fly, after 5 min of flight). However, as the period of flight is extended, the apparent rate decreases very rapidly, so that the thoracic trehalose level actually continues to rise with increasing duration of flight period. It is concluded that, following initial rapid utilization of trehalose, a secondary metabolic pool becomes implicated, so as to restore (and maintain) the thoracic trehalose levels at as high as 50 per cent of that of unflown flies, for thoraces of flies which have been permitted to fly for as long as 4·5 hr. Flight-exhausted flies, when fed on a solution of glucose, fructose, maltose, sucrose, and trehalose, resumed flight, without external stimulation, but feeding galactose, mannose, and cellobiose failed to do so. However, injection of solutions of glucose, fructose, sucrose, and trehalose did not initiate flight in such flight-exhausted flies. These data indicate that a complex, metabolic route is normally involved in the energizing of flight.

Function of Carnitine in the Fatty Acid Oxidase-deficient Insect Flight Muscle

Abstract The metabolic function of carnitine in the fatty acid oxidase-deficient flight muscle of the blowfly, Phormia regina, was investigated. Mitochondria from flies did not oxidize palmitate or hexanoate in the presence of adenosine triphosphate, coenzyme A, carnitine, and serum albumin. Palmitoyl carnitine was oxidized at an extremely slow rate, QO2 of 20. The rate of synthesis of the carnitine ester was much slower and is rate limiting in fatty acid oxidation. Hexanoyl carnitine was apparently not metabolized. Flight muscle of flies, however, has a concentration of carnitine of over 4 µmoles per g, wet weight. These findings suggest that the primary function of carnitine in blowfly flight muscle is not related to utilization of fats. Carnitine increased the rate of oxidative decarboxylation of pyruvate-1-14C to acetyl-CoA. The malonate inhibition of the rate of production of 14CO2 from pyruvate-1-14C, but not from pyruvate-3-14C, was relieved by carnitine. The rate of oxidation of pyruvate-3-14C to 14CO2 was inhibited by carnitine. These effects of carnitine may be explained by the formation of acetyl carnitine from carnitine and acetyl-CoA, derived from pyruvate, catalyzed by an active carnitine acetyl transferase. Approximately 90% of the enzyme was found in the mitochondria of the muscle. Acetyl-CoA, in the presence of carnitine, was not oxidized by mitochondria, although acetyl carnitine was oxidized with a QO2 of over 300. This indicates that blowfly mitochondria are not permeable to acetyl-CoA but are permeable to acetyl carnitine. When both pyruvate and acetyl carnitine were available, pyruvate was used preferentially. The concentration of acetyl carnitine in flight muscle of blowflies increased 4-fold on initiation of flight, paralleling the increase in pyruvate. After about 1 min of flight, the level of acetyl carnitine decreased and attained a steady state at a concentration twice that in the muscle at rest. Functions for carnitine in carbohydrate utilization, resulting from the direct action of carnitine on pyruvate metabolism, are proposed. A comparative study of the metabolism of carnitine in blowflies and bees is described.