Fenisse

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  1. XXX: Reaching for the Stars, Part 2 Absolute Beginners The Aquarius Abort Tests, also known as Aquarius Phase I, had been an almost complete success, save for the failure of one of the motors on the AT-3 flight. Nonetheless, the three flights had demonstrated that the abort system worked and, most importantly, it worked well. The IASRDA was therefore ready to move into the second phase of the program. Aquarius Phase II would involve suborbital flights, which would verify the structural integrity of the spacecraft during the most hideous parts of flight; i.e. during atmospheric re-entry. Atmospheric re-entry of a manned vessel was something never attempted before; indeed, atmospheric re-entry of an orbital spacecraft was a very novel concept altogether. It must be remembered that, at this point in time, the only two IASRDA objects to ever be recovered from an orbital flight had been Ethereal 6 and 7, and even then, the re-entry section on those missions was nothing more than a small capsule with a time-activated parachute and an ablative shield – nowhere as complex as a manned spacecraft. Blueprint of the Aquarius Block II spacecraft. The Aquarius Block II spacecraft was almost identical in appearance to the earlier Block I; most of the changes that had been made were not superficial, but they were nevertheless essential to make the Aquarius capsule a proper space-capable vessel. First of all, the (relatively) inexpensive materials used for the construction of the pressure hull were exchanged for the René 41 nickel alloy, developed by General Electric – this new material had been conceived to retain a high structural strength even at extreme temperatures up to and exceeding 1000° Celsius (1800°F, 1273K). Moreover, the pressure hull was now actually able to be pressurized, and all the instrumentation, seating, and life support systems were mounted and connected to the electrical system, whereas the Block I only contained lead weights to simulate the presence of all that is described above. The astronauts would be seated in a forward-facing custom-fit fiberglass seat, with their back to the heatshield. Apart from ascent and re-entry, they were allowed to fly with the pressure suit uninflated: this allowed them to have better control and freedom of movement – flying with the “visor up” was made possible by the pressurized cabin, and its internal pure-oxygen atmosphere rated at 5.45psia (37.6 kPa), roughly equivalent to an altitude of 25000ft (approx. 7620m): this simplified atmospheric control compared to a mix of O2/N2 at sea level pressure. The astronauts had complete control over the three axes of stability: pitch, yaw, and roll. In fact, in an emergency, the person aboard would be capable of switching to manual control, and possibly land the spacecraft “by hand”. On a normal flight, however, guidance would be provided by a series of IBM 701 computers on the ground, which would then relay their commands via a number of ground stations and, if available, via the Connection satellites in orbit at that point in time. The descent and control section and the escape tower were identical to those of the earlier Block I craft; the only difference was that, on the Block IIs, the explosive bolts that were meant to separate the tower from the rest of the spacecraft were actually in place and armed. Another addition, probably the easiest to spot of them all, was the retrofire package mounted below the capsule. This consisted of a 1.3m in diameter by 0.4m in length tank assembly, containing 87.4L of HTP. The peroxide would be fed in two 888N thrusters, for a total of 1.776kN of thrust. The two thrusters would burn for 88.3 seconds at most, providing a maximum of 102 m/s of delta-V, just enough to re-enter from a low Earth orbit. The retrofire package was completely controllable by both astronaut and ground crews: it could be shut down at the operator’s pleasure, and its thrust could be completely controlled by a series of valves. To fulfill the objectives of the Aquarius Phase II, the IASRDA took quite an unconventional approach. Instead of developing and qualifying an entirely new launch system, they would re-use already available hardware. The IASRDA had manufactured an excess of Deacon I rockets back in the day, hoping to use them to launch satellites, and in 1960, three were still ready for use at a moment’s notice and without requiring a vast amount of money to operate. Moreover, the Deacon was found to be a perfect match for the Aquarius capsule, and was deemed capable of performing the suborbital missions required by the second phase of the program. Schematic of Aquarius Block II mounted on Deacon I. The configuration depicted above is named, unimaginatively, Aquarius-Deacon. The capsule was somewhat larger in diameter compared to its launch vehicle (2m vs 1.8m), and so required an awkward adapter, in place of the standard nosecone, to attach it to the rocket below. Apart from that, there was no difference between the original Deacon I and the modified version that would be used in the Aquarius program. The IASRDA decided to launch at least one unmanned suborbital mission before attempting a suborbital manned flight, and even then, a crewed Phase II mission was deemed unlikely to ever happen, considering the risks of such a launch: the main concern was with the g-forces that would be experienced by an astronaut during a suborbital descent; very likely in excess of 8gs, and probably even as high as 14gs – these accelerations, if sustained, may prove to be lethal or, at the very least, may cause severe damage to the occupant of the vessel. Therefore, the first suborbital launch, Aquarius 1, would be unmanned, with a lead ballast in place of the astronaut. It would be flown aboard Deacon I n°23, and had been scheduled for February 23 1961, just over a month from the AT-3 flight: this was only possible due to the extremely tight launch schedule defined by the IASRDA – prioritizing the Aquarius missions at the expense of almost every other program’s. The rocket and capsule were rolled over to the newly constructed Launch Complex 4 by February 22, and after some quick tests, the rocket was approved for launch on the next day, entirely within schedule. Image 19610222A. Aquarius 1 at LC-4. One night later, the capsule would be on its way to the edge of space. The rocket was cleared for take-off at 1107 hours in the morning of February 23. Weather conditions were good, although there was a slight overcast, but it was unlikely to affect the outcome of the mission. Image 19610223A. Launch of Aquarius 1. Notice the clear exhaust of a Etholox rocket engine (in this case, the NAA-75-110 A-6) The Deacon I started its pitch program a T+20 seconds into the flight, with the rocket pitching down at 0.5deg/s from 90° to 45°. Image 19610223B. The Deacon I starts its pitch program to 45°. Aquarius 1 reached 45° degrees pitch at T+110 seconds, and would maintain attitude from that point on, also using the Deacon nitrogen ACS if necessary. Image 19610223C. The ground cameras take one last glimpse at Aquarius 1. The guidance program was set to either complete the Deacon burn, or disengage the engine once the predicted apogee was above 185km. In Aquarius 1’s case, the flight had been planned not to reach that altitude, instead aiming for 155km. The Deacon I exhausted all of its propellant at T+140 seconds. SIMULATION. MECO has just occurred, and for now the Deacon is holding attitude via the nitrogen ACS. Fifteen seconds later, at T+155, the abort tower was ditched, as it wasn’t necessary anymore. SIMULATION. The abort tower separates from the rest of the craft. And, another five seconds later, the Aquarius capsule separated from the Deacon, and fired its two HTP motors for three seconds to maneuver away from the booster. SIMULATION. The thruster pack firing to separate the Aquarius from the Deacon. Twenty seconds after separation, at T+180, the capsule initiated its turn-around maneuver, rotating by 180° on its yaw axis. The capsule reached apogee five minutes and twenty seconds into the flight, at T+320. At that point, the retro rockets had been intended to fire, but a failure of a valve in the HTP system prevented it from happening. The motors were ditched successfully, but Aquarius 1 would come down faster than originally intended. SIMULATION. Aquarius 1 descending towards the Ocean. The capsule reached sustained deceleration forces in the order of 10.34gs during descent, which would have likely made most, if not all, astronauts pass out at the very least. Nonetheless, the automated control system kept operating the spacecraft without further incident, releasing the parachute cover at 19km, arming the parachutes in the process. The capsule landed safely in the Atlantic Ocean after a flight of 16 minutes. It was recovered about an hour and a half after splashdown by the US Navy. The mission had only been a partial success. The telemetry data from the flight revealed that the boost phase had gone smoothly, and the Deacon had performed well above expectations. What had underperformed, unsettlingly, was the Aquarius capsule. If the flight had been manned, and fortunately it wasn’t, the occupant may have been tragically lost during descent. Telemetry recovered from Aquarius 1. An investigation revealed that not only the HTP propulsion system had underperformed, to use a euphemism, but also that the onboard Aquarius control computer had had problems in maintaining attitude throughout the second phase of the flight. These problems were solved by the engineering teams without much trouble, however, the next missions would need to be significantly delayed in order for the changes to be made to the capsule. Despite the many issues that had plagued the earlier flight, and the further delay caused by the mandatory upgrades to the Aquarius capsule, the next mission of the program would be ready for launch in exactly a month. Every engineer and technician at the IASRDA had worked around the clock to ensure this was the case. It seemed impossible, but Aquarius was actually bringing people together for a common goal. Aquarius 2 would launch on March 23 1961, twenty-eight days after Aquarius 1, and even from the same launch pad: LC-4. Image 19610323A. Aerial photograph of Aquarius 2 twenty minutes before launch, with LC-4 already evacuated. Ignition of the Deacon’s main engine occurred at T-3, and liftoff would take place three seconds later, at T+0, after the turbopumps started running at full speed. Local time was 1011 hours. Image 19610323B. The launch clamps release the Deacon I, its engine already roaring. As predicted, the pitch program was initiated at T+20 seconds into the flight. The mission specifics would be very similar to those of Aquarius 1, so the Deacon would pitch over at a rate of 0.5°/s Image 19610323C. The Deacon I in flight. Notice the clear Etholox exhaust plume. 45° pitch were reached at exactly T+110 seconds. The Deacon was instructed to hold that attitude for the rest of the flight. SIMULATION. Aquarius 2 leaves the Cape behind as it continues to climb through the atmosphere. Main engine cut off took place at T+140. The rocket kept drifting towards apogee, and at T+155 the abort tower was separated from the rest of the vessel. SIMULATION. Separation of the escape tower. As usual, its SRMs are extremely underexpanded at this altitude. Five seconds later, the Aquarius capsule decoupled from the Deacon rocket that had carried it all the way to the edge of space. SIMULATION. The HTP thrusters come online for a few seconds to ensure the Aquarius separates correctly. At T+180, the capsule was instructed to begin the turn-around maneuver. The capsule oriented so that the heatshield would face forward. SIMULATION. The capsule orients with the heatshield towards the airflow. The capsule then drifted towards apogee, which, at 168km, was higher than that of Aquarius 1. The likely cause of this was to be found in the upgraded computer system, since it could relay the guidance information much more precisely than before. Nevertheless, the higher apogee was an intended mission parameter. The Aquarius reached that point at T+296, at which moment the computer ignited the retro-kick motors for a whole 1 minute and 25 seconds, providing a 99m/s velocity change in the retrograde direction. SIMULATION. The retrograde burn in process. You can see the Deacon I booster above and to the right of the capsule. At T+381 the retro-burn was completed, and two seconds later the thruster pack was discarded, and the capsule readied for descent mode. SIMULATION. The thruster package, once expended, is discarded to allow the heatshield to protect the craft during re-entry. The capsule would then start its descent towards the ocean, reaching a maximum deceleration of 9.5gs as it reached the denser layers of the atmosphere. 9.5gs was better than the 10.34gs of the earlier flight (especially considering Aquarius 2’s higher velocity), but it still was higher than what the IASRDA would have liked. SIMULATION. Although the most stressful part of descent has been completed, the capsule is not in the clear yet. At 17km and T+518, the descent module was ditched, arming the capsule’s parachutes in the process. The drogue deployed at T+568, at an altitude of 9.7km. The first stage of the parachute system was meant to get the capsule to a safer speed for mains deployment. SIMULATION. The drogue chute, deployed but not yet inflated. The drogue fully inflated at 5km, bringing the capsule down to 51m/s vertical speed; finally, at T+665 the mains were released, and the capsule was now on final descent towards the Atlantic Ocean. SIMULATION. Much lower in the atmosphere, the three main chutes are deployed. Aquarius 2 splashed down roughly 571.5km downrange from the Cape at a downward speed of 3.9m/s, 870 seconds, or 14 minutes 30 seconds, after liftoff. The capsule was recovered not more than 30 minutes after splashdown, a testament to the training regimen that the IASRDA and the US Navy had developed to cut down capsule recovery times to less than one third of before. SIMULATION. With the parachutes deployed and inflated, Aquarius 2 can gracefully glide towards the Atlantic Ocean for a soft splashdown. Telemetry data from the full Aquarius 2 flight, from launch to splashdown. The Aquarius 2 mission had been a total success. Defying Murphy’s law [and, from the writer’s perspective, even Agathorn’s] in its entirety, at least for the moment, everything had worked perfectly. No one, for the first time in the entirety of the IRS and IASRDA history, had committed any mistakes. It was time to make this the rule, not the exception. Now only one or two more test flights were what was left between the Agency and being able to put a man in space before the Soviet Union.
  2. @Cavscout74 well, you joined us at probably the best time possible, at least for the near future of the series. The next 3-4 updates will be quite something, at least when I'll find the time to sit at my computer and actually write them. So if you need to do some catching up, you should have all the time in the world. Well, hopefully not too much time. Anyways, as always, thank you all very much for the support!
  3. XXIX: This Side of Paradise, Part 5 New Angels of Promise Although the manned space program was what made the front page on newspapers as of late, the true workhorse of the IASRDA was still the almost-forgotten Ethereal program, and its goal of uncover the many secrets that Earth still was hiding, most of the time in plain sight. The new capabilities of the Hyperion ELT-Alcor B rocket meant that heavier, more complex, Earth orbiting satellites were not only possible, but also achievable at a fraction of the cost of before, when a Prometheus would have been needed. As the Connection Block IIb-class communications satellites were scheduled to launch only from August of 1961, the new Ethereal missions would also be the most complex ever performed by any spacecraft before, including the three Pathfinder missions. The Ethereal probes were different in design compared to those of the other programs – actually, what differed was their design process. While Explorer, Connection and Pathfinder spacecraft were based around “blocks”, Ethereal ones were instead manufactured on a per-requirement basis. Although this meant that each probe could be custom made for its exact purpose, it also signified that each satellite would cost much more than any other from a different program. To obviate this serious issue, the IASRDA engineers made sure that, even though a probe may be manufactured to its mission requirement, as many already tooled parts as possible should be used. A solid compromise. Ethereal 9 schematic. The Ethereal 9 satellite was the first to exemplify that design choice. Although being unique, it was based around parts designed for the Connection satellites. Ethereal 9 was a 148kg satellite, designed to function as the functional navigational satellite of the program. It carried almost 8kg of navigation equipment in the top compartment, which was covered by the solar cells necessary to keep the satellite functioning for extended periods of time. The probe was equipped with 9kg of hydrazine propellant on board, necessary for small orbital adjustments and station-keeping. The rest of the weight was mostly the onboard computer, the RCS ports, and the four antennae. The launch, a very complex one, was to be performed by a Hyperion ELT-Alcor B. The rocket would first insert the payload and second stage into a highly inclined orbit, and then the hard phase would commence. The Alcor would need to burn a second time to raise the apogee of the payload to 850km, and then burn a third time to circularize the orbit at apogee. An undoubtedly feasible mission given the Alcor B capabilities, but nonetheless extremely prone to failure. The launch of Ethereal 9 was scheduled for February 9, 1961. The rocket would be launched from LC-1, although with seven pads, of which three had been constructed in the past three months, there now was a wider selection of launch sites than ever before. Image 19610209A. The Hyperion-Alcor B pictured early in the morning at Launch Complex 1. The rocket lifted off at 1224 hours, with the goal of reaching a preliminary orbit at 185km with an inclination of 64.6°. Image 19610209B. Lift-off in unusually clear skies. The rocket’s path would take it very near to the coast of Florida, although it would not pass directly over it. The LR79-NA-11 were by now the safest first stage engines in use around the world, with a mean-time-between-failures estimated at 274.94 minutes. SIMULATION. Perspective gives the impression the rocket will pass over Southern Florida; however, this is simply an optical illusion. The first stage burn was completed nominally, with MECO occurring at T+163, and with the Alcor separating and igniting for the first time a second later. SIMULATION. Separation of the first stage. Notice the separation motors firing. Fairing separation occurred at T+223, at 116km altitude. SIMULATION. Fairing separation The stage entered orbit at 185km at T+441. The Alcor stage still had 27.3 seconds of fuel remaining, which amounted to around 914m/s of delta V, more than enough to complete the mission. SIMULATION. The Alcor B has just entered orbit, and the AJ10 is still warm from the insertion burn. The Alcor would coast for 21.5 minutes, at which point it performed its second burn of the flight, at 185.8m/s, which would raise the craft’s apogee to 850km. SIMULATION. The Alcor ignites for a second time. The stage and payload would then coast again for another 47 minutes, when it would perform its third and final burn of the mission, rated at 175.2m/s. SIMULATION. Magnificent render of the third and last Alcor burn of the mission. Ethereal 9 had been placed in its intended 850x825km orbit at 64.602° inclination, and with a period of 1 hour 41 minutes and 31 seconds. The spacecraft detached itself from the Alcor stage, which then performed a small ACS burn to clear itself from the satellite’s trajectory. SIMULATION. Another breathtaking shot, this time of Ethereal 9 only. Ethereal 9 would continue to operate for two years, during which time it was used by surveyors on the ground to determine their ground location, coupled with readings by the earlier Ethereal 8. Nevertheless, this first generation of navigational satellite would soon be superseded by the second, more capable one, which would bring something new to the table; most importantly, an extended lifetime and a new source of power which would, in later years, prove to be essential for the success of many missions. Alas, despite the incredible successes of the Ethereal program, it was but a sideshow in the greater scheme of things, with the world’s attention focused on only one, single thing: getting a man in space. Before the Soviet Union.
  4. @KerbalKore thank you very much! Also thank you for bringing to my attention that reactions have been temporarily disabled. I hadn't noticed (I've also not been active for almost a month, so there's that).
  5. Chapter III XXVIII: Reaching for the Stars, Part 1 Aquarius Abort Tests The Aquarius Program was undoubtedly the top priority of the IASRDA in the years following its announcement. Many resources and personnel had been diverted almost immediately to the project, to ensure the Agency would send a man into space before the Soviet Union. Many essential pieces of hardware had been developed for the program, including the spacesuits and life support equipment, and by mid-1960 finally a design for the capsule had been chosen. The contract was awarded McDonnell Aircraft and English Electric, who would respectively assemble the hull of the capsule and its escape tower, and the hatch, RCS system and parachute compartment of the spacecraft. Another contract was awarded to de Havilland Propellers to develop a small solid-fueled rocket to test the abort tower design. Aquarius Block I schematic. The Aquarius Block I was 2 meters in diameter and 2.8 meters long, with the escape tower the total length became 6.7 meters. With the abort tower mounted, and the capsule fully loaded, the spacecraft weighed 1638kg, without the tower the weight decreased to 1236kg. The capsule was cone shaped, with a blunt, convex base, which carried the heatshield, made out of an aluminum honeycomb covered by a series of layers of fiberglass. Above it, in the conical section, was the pressurized crew compartment. The astronaut would be seated in a custom-fitting seat, with his back to the shield and the spacecraft instrumentation in front of him. Below the seat was the life support equipment. Above the pressurized section were the recovery parachutes, contained inside the descent compartment. This compartment contained the hydrogen peroxide reaction control system that would control the spacecraft attitude during descent from orbit, as well as the orbital antennae. The descent section would decouple at 15-13km altitude, at which point final descent would begin. The first parachute to deploy would be the small drogue chute, its main role was to slow the capsule down to safer speeds for the main parachutes. After the drogue fully inflated, the three main parachutes were deployed; this was for redundancy purposes, as the spacecraft was designed to land safely on two. The capsule would then splashdown into the ocean at 6.1m/s and an airbag would deploy to keep the spacecraft afloat. Above the descent section was the abort tower. This system was designed to pull the crewed compartment away from a failing booster; the astronaut would be subjected to accelerations of up to 9.45gs in this case. One difference between the Block I capsule and the later Block II used on the real flights was the abort tower: the one on the former version couldn’t separate from the descent section, and was decoupled alongside it. Blueprint of the Aquarius Test Vehicle. The Aquarius Test Vehicle (Aquarius TV) had been developed by de Havilland Propellers as a cost-effective way to test the spacecraft’s abort system. It was 2 meters in diameter, matching the capsule, and was 6.4 meters in length, fins included. The main powerplant of the rocket were four Thiokol Castor 1 solid rocket motors, similar to those used to augment the Hyperion and Prometheus launch vehicles. The motors were assembled in two pairs: 1-3 and 2-4; each pair was capable of independent firing, depending on mission parameters. The rocket had no attitude control and depended on launch angle for the flight characteristics. In total, six Aquarius TVs were assembled, of which three were used with the Aquarius Block I spacecraft, on the missions AT-1 through AT-3. The first of these firings, AT-1, took place on November 15, 1960. The test was designed to prove the feasibility of an abort on the launch pad, in a “zero speed-zero altitude” scenario. Image 19601115A. Aquarius AT-1 at LC-3, waiting for the launch command to be given. The weather was quite cloudy at the Cape, but as the test was supposed to only fly to a limited altitude, this was deemed not to be an issue. Ignition would occur at 1214 hours at the newly constructed LC-3 launch pad. The abort tower ignited immediately and the explosive bolts below the spacecraft detonated without issue. In a matter of seconds, the capsule had been safely pulled away from the test vehicle; although not much was seen of the first few moments of flight since the extreme thrust produced by the abort tower raised a lot of dust. Image 19601115B. The abort command is given, and the Aquarius capsule blasts off from the rest of the rocket. 2.5 seconds after the abort took place, the capsule was visible again. It coasted through the air for some more seconds, while the onboard chronometers were running and ready to engage the second part of the abort sequence. Image 19601115C. The abort tower has exhausted its propellant, after successfully carrying the capsule away from the test vehicle. At 10 seconds after abort, the descent compartment and ascent tower were decoupled from the crew module, and the parachute system was engaged. Image 19601115D. The abort tower and descent section have separated from the pressurized section, which now coasts freely to apogee. The rocket reached a maximum altitude of 862m from sea level, at which point the main parachutes were finally able to deploy. Image 19601115E. As the capsule starts descending again towards the Earth, the trio of parachutes deploys. The chutes fully inflated a few seconds later, and the spacecraft landed safely on the shores of Florida 107 seconds after the abort sequence was initiated. The second test, AT-2, would take place just more than a month after the first, on December 21, 1960. Lift-off occurred at 1000 hours. Image 19601221A. Aquarius AT-2 lifts off successfully from LC-3. For this flight, only two rocket boosters, numbers 1 and 3, would be ignited: the purpose of the test was to verify the escape tower’s ability to separate the spacecraft successfully at low altitudes and high dynamic pressures. Image 19601221B. The Aquarius TV reaches max Q. The abort motors fired once the rocket was above 2500m in altitude. Image 19601221C. A few moments after max Q, the escape tower engages. As usual, 10 seconds after the abort command was sent, the abort tower and descent section separated via the small solid motors contained within the latter. Image 19601221D. The abort tower and descent module separate from the pressurized section. Notice the two small separation motors at the bottom of the abort tower. The rocket coasted up to an altitude of 4994 meters, at which point the drogue chute was finally able to deploy, and later the main parachutes as well. Image 19601221E. An helicopter closes in to the capsule as it is about to land, and takes a nice photograph of it with the parachutes fully deployed. The capsule landed without issue 151 seconds after launch, in the ocean four kilometers offshore from the Cape. It was recovered successfully twenty minutes later. The rocket which it flew on crashed into the Atlantic Ocean, and was destroyed. The third and final abort test, AT-3, would occur on January 14, 1961, which also made it the first worldwide launch of the year. Image 19610114A. AT-3 at LC-3. This is the only color image available of the Aquarius Test Vehicle with the Aquarius Block I capsule mounted. The ignition signal was sent at 1106 hours, and just a moment later the rocket was taking off to the skies. The solid motors would fire in sequence, 1-3 first and later 2-4 once the first burn was finished. Image 19610114B. Aquarius AT-3 takes off. The first part of the burn was successful, but Castor number 2 failed to ignite in flight. Nevertheless, the test proceeded, and the abort signal was sent at max Q at an altitude of 11200m. Image 19610114C. Aquarius AT-3's exhaust plume. The capsule and its booster are no longer visible, unfortunately. Ten seconds after abort tower ignition and spacecraft separation the top assembly was separated. The capsule coasted to an altitude of 14399 meters, at which point the drogue chute deployed. The spacecraft landed safely 16km offshore, in the Atlantic Ocean, after a flight of 396s. Unfortunately, due to the distance from the launch complex, and the small size of the craft, no other photos exist of the flight. While the flight was not entirely successful, and final velocity and max dynamic pressure were lower than intended, it still proved that the Aquarius spacecraft’s escape tower worked as planned. However, there was no more time for testing the abort tower. As the race to get a man into space drew closer and closer, it was necessary to test the final spacecraft on a spaceflight – not in orbit, yet, but on a couple of suborbital launches.
  6. Heh, took me some time to get a good tone out of that Tele, but once I learnt how to, I rarely needed anything else: I can play every genre on it, bar metal probably, but I don't really play that stuff -- and even then, just switch the neck pickup for an humbucker and you should be good to go. Telecasters are really an exercise in simplicity; nowadays I mostly use a wah pedal, an OD/Distortion pedal and some reverb, sometimes I like to add some delay. Just follow the twang and you're good to go. Also great guitars to play in fingerstyle and clawhammer techniques. About Gibsons, I have a lot of experience with Les Pauls (my very first electric was one). Heavy, weird to reach the upper frets, that G string detuning every time you need it... but really amazing sound, in particular with coil tapping. I'd say it's probably best to get a PRS these days. Or, if you don't want to spend much, Epiphone Standard Pro LPs are great for their price. My 1.7 KSP installation, which is way heavier and with many more mods than the RP-1 one, tops out at 13k patches, for comparison.
  7. XXVII: Connecting the World, Part 2 Communiqué The Connection 2 test early in 1960 had proved that communications could be relayed through the use of satellites, but had also shown that for such a network to be feasible with the current technology, the spacecrafts would have to be placed in substantially higher orbits than ever before. All objects in orbit complete one such lap around the parent body in a specific time period, called orbital period; as an example, the first artificial satellite of Earth, Ethereal 1, had an orbital period of 2 hours, 4 minutes and 6 seconds. In general, an object in a circular orbit will have a shorter orbital period the closer it orbits to the parent body; i.e. if a satellite orbits at 200km from the planet’s surface, it will complete the lap in less time than if it were orbiting at, say, 600km. Astrophysicists calculated that a spacecraft in a circular orbit exactly 35,786km from the Earth’s surface would complete the orbit in exactly 23 hours, 56 minutes, and 4 seconds, the length of one sidereal day. Such a satellite, when seen from the ground, would appear to return to the same point in the sky each sidereal day, tracing a path similar to an eight-figure, with characteristics depending on the orbital inclination and eccentricity of the spacecraft. This is what is called a Geosynchronous Orbit, abbreviated GSO. A particular case of geosynchronous orbit is the Geostationary Orbit, or Geosynchronous Equatorial Orbit (GEO), in which the objects orbits in the Earth’s equatorial plane, with an inclination of 0°. A satellite in such an orbit would appear completely motionless in the sky to a ground observer, rendering it perfect for a communications satellite, since ground-based antennae wouldn’t need to rotate to track the spacecraft’s motion. Unfortunately, such an orbit was beyond the capabilities of any IASRDA launch vehicle of the time, so a simpler to achieve GSO was selected instead for the next Connection missions. Schematic of the Connection Block II satellites. The Connection Block II satellites were small communication satellites weighing 195kg. They carried 9kg of communications equipment, and were outfitted with two small omnidirectional antennae for data relay. The probes carried 79kg of hydrazine in the aft compartment, and attitude control was provided by four 4-way 24N thrusters. The launch vehicle selected to launch the satellites was the Prometheus B-Arcturus B. Schematic of the Arcturus B upper stage. The Arcturus B was a much-improved variant of the earlier A model. The engine had been upgraded to the XLR81-BA-7, which produced 71kN of thrust at a vacuum specific impulse of 285 seconds, while still burning the same UDMH/IRFNA-III mixture as the earlier variant. Another improvement over the A model was the capacity of the new engine to restart in space. The tanks had been thoroughly overhauled, both of them were now 1.7m in diameter, while the bottom 1.4 tank had been modified to house the hydrazine for the ACS as well as the pressurant for the main tanks. The avionics package had remained mostly the same, with minor upgrades to allow for finer control of the stage. The stage was capable of mounting either an X-242 or X-248 kick motor, depending on mission parameters, for any beyond-LEO class mission. When used in conjunction with a Prometheus B, the launch vehicle was capable of lifting a maximum of 2719kg to low Earth orbit, or up to 636kg to a Geostationary Transfer Orbit (GTO) when paired with the X-248. The first launch of a Connection Block II, Connection 3, was scheduled for December 15, 1960. Image 19601215A. The Prometheus B-Arcturus B at LC-1, awaiting lift-off authorization. The rocket took off at 9 in the morning, when weather conditions were deemed to be good enough for a launch. Image 19601215B. The two LR79 create a majestic exhaust plume as the rocket ascends through the first few thousands meters of atmosphere. Without a single cloud in the sky, the camera crews were able to track the rocket for much longer than ever before; while the launch date hadn’t been selected for this purpose, it was still a very appreciated side-effect. Image 19601215C. The Prometheus passes through Max Q at an altitude of 15.5km. The plume expanded considerably. Unfortunately, once above roughly 20km, the rocket became too small in perspective for any appreciable photograph to be taken. MECO occurred at T+156, and separation of the second stage occurred just a second later. SIMULATION. The second stage ignites successfully. Fairings separation occurred at T+330, with SECO happening a minute later. The Arcturus B stage separated and ignited for the first time. SIMULATION. The Arcturus A separates from the upper stage of the Prometheus launch vehicle. The Arcturus stage provided for the last 1700m/s of velocity to orbit. The stage and payload would then coast in their 185km parking orbit until the proper time for the second burn was reached. The requirement for the GTO burn to be performed by the Arcturus stage was the main reason why Connection 3 was launched aboard a Prometheus, even though a Hyperion would have probably been able to do the job just fine. The X-242 kick stage wouldn’t be used to execute the transfer maneuver, actually it served the purpose of circularizing the orbit at apogee. The second Arcturus burn, 2460m/s in delta v, would occur as the stage passed the equatorial descending node, exactly 16 minutes and a half after orbital insertion. SIMULATION. The Arcturus ignites for the second, last, time. With the payload placed onto its transfer orbit, it was finally time to spin stabilize the kick motor and separate it, delaying ignition until it reached apogee 5 hours and 15 minutes later. SIMULATION. Connection 3 and its X-242 kick stage drift towards apogee. The apogee burn would require 1470m/s of delta v, of which 1440 would be provided by the kick motor, with the onboard RCS concluding the burn. SIMULATION. After the solid motor burn is complete, Connection 3 circularizes its orbit via its RCS thrusters. SIMULATION. Connection 3 in orbit over Southeast Asia. After the burn was finished, Connection 3 had been placed into a 35802x35783km orbit at 28.609° inclination, with an orbital period of exactly 23 hours, 56 minutes, and 4 seconds, a sidereal day. The satellite orbited above Southeast Asia, and started relaying messages from ground stations in Australia six hours after final orbital insertion. The satellite is still in orbit to this day, although the exhaustion of the hydrazine propellant means it no longer is in a geosynchronous orbit. Connection 3 would be only the first of a long line of geosynchronous communication satellites, with the first generation of them due for launch starting the following year.
  8. So guys, very quick update. I'm working right now on the post-processing for Update XXVII; in fact, I just re-launched KSP to get some more shots. I'll post the update either in a few hours, or tomorrow morning (Italian time), depending on how smoothly things go. This is the last part of Chapter II; soon we'll enter into Chapter III, where the fun stuff (and, with all probability, many explosions) starts to happen. By the way, since my RP-1 install of KSP takes around 10-15 minutes to load, I generally do something else. Today I was trying some Dire Straits-y licks on my Telecaster, sitting near my computer. I randomly stared at the screen (probably a change in background caught my attention), when I noticed the Module Manager patch counter was... well... Welp. And to think I deleted a lot of parts and mods that I wouldn't be likely to use, I'm quite sure when I first installed all the mods the total patch number was probably closer to something like 140-150k. Now I can understand why it takes so long to load. Well, better for me, more time to completely destroy the frets on my guitars. No Telecasters were harmed in the making of this post.
  9. @Geschosskopf thank you very much! I've also been spending some more time on post-processing the images, in particular I've been redrawing the rocket plumes on the "photographs" by hand, as I was not satisfied with the RealPlume ones.
  10. XXVI: This Side of Paradise, Part 4 Navigation from Above Humanity had been navigating the oceans since the earliest of times. Many civilizations learnt to use several techniques to determine their location, the most important of which was the observation of celestial bodies. Among those who sailed the ancient seas were the Austronesians, the Polynesians, the Greeks, the Phoenicians, the Carthaginians and even the Romans. In the medieval times the greatest advancements in the art of navigation were made by the Arabs, who developed extensive trade routes ranging from the Mediterranean Sea to the China Sea. They made use of magnetic compasses, the quadrants, and the kamal to navigate the oceans, even without the need to follow the coastlines. In Northern Europe, the Vikings developed methods to allow navigation in overcast skies through the use of the Sunstone, and possibly even reached the coasts of North America centuries before Columbus did. In the following centuries, navigation became fundamental to the thriving of nations. The development and use of the astrolabe in the 1400s, of rudimentary clocks such as the hourglass, of much more precise quadrants, maritime maps, and, later, of the marine chronometer and sextant, made navigating the seas easier, but still no mundane task. These tools, and others, allowed Columbus, de Gama, Magellan, Barentsz, Cook, and many others to discover many new places, and ushered the world into the Age of Exploration, with all the geopolitical, social and technological consequences of the case. In the modern era, radios started appearing on ships, and soon it was found that they could be used to aid in determining a ship’s location, and also in calibrating the onboard chronometers. By the end of the Second World War, RADARs had become the norm on most warships, and radio navigation had become widespread especially in aviation, and made night operations a far easier task to complete successfully. More recently, scientists at various institutes across the world had calculated the position and velocity of the early Ethereal 1 and 2 satellites by measuring their doppler shift, the change of frequency of a wave in relation to an observer who is moving relative to the wave source (a very simple example of this phenomenon is the change of pitch of an ambulance siren as it approaches and then recedes after it has passed by). Researchers at the IASRDA thought that by working backwards, it would be possible to use a satellite to determine the accurate positioning of an observer. After years of development, finally a test satellite was to be launched as part of the Ethereal program: Ethereal 8. Schematic of the Ethereal 8 test Navsat. The heavy, 163kg satellite required a high inclination orbit, and could not be spin stabilized, so that prevented the use of a solid kick stage. Therefore, the IASRDA decided to test the newly developed Alcor B stage, which had been widened to 1.5m in diameter, had new avionics, and also used the new AJ10-104 engine (which could be restarted in space), in the Hyperion ELT-Alcor B configuration. This vehicle was capable of inserting 400kg into a 185km LEO at 29° without the use of a solid kick stage (that could still be fitted if the mission was beyond-LEO). Blueprint of the Alcor B upper stage, diameter: 1.5 meters. The launch had been scheduled for November 11, 1960 at the Cape Canaveral LC-2 pad. The launch was to occur at first light for meteorological reasons. Two US Navy cruisers and a Royal Navy destroyer were positioned downrange, roughly 400 nautical miles from the complex. Image 19601111A. Sunrise at the Cape, the Hyperion-Alcor ready to launch after the final checks are completed. Liftoff took place at exactly 0600 hours, in somewhat clear skies, but with severe overcast arriving at the launch site in the morning. Image 19601111B. Ignition of the main engine... and we have lift-off! The payload would be placed in an orbit with an inclination of 47° at an altitude of 330km. Due to launch safety considerations, the rocket would go north, compared to the southbound launches of past high-inclination satellites. Image 19601111C. The chase camera operator takes one last shot at the rocket as it disappears into the clouds. Second stage separation occurred as planned 2 minutes and 44 seconds into the flight. The ACS separated the two stages and a few moments later the AJ10 ignited. SIMULATION. Notice the separation motors on the lower stage. Fairing separation took place at T+187 seconds, at an altitude of 116km. SIMULATION. Fairings deployed, continuing to orbit. With the payload now exposed, the Alcor B stage was now just four minutes away from orbit. SIMULATION. Notice the much longer nozzle of the new AJ10-104 engine, this improves performance significantly. Orbital insertion occurred after 7 minutes and 44 seconds, with Ethereal 8 separating at T+591 seconds. It then performed some small burns to adjust its orbit to a 332x330km one with a period of exactly 1 hour and 31 minutes, where it remained for more than 4 years. SIMULATION. Ethereal 8 in orbit around the Earth. The three ships positioned downrange were able to receive data by Ethereal 8’s second orbit, although getting a usable fix took almost a day of fiddling around, and required the help of ground stations. Nevertheless, on the following day, November 12, the three ships were able to obtain their approximate location, with considerable error, by only using data received by the satellite. The system worked, but just one satellite would not be sufficient to provide an accurate service: an entire "constellation" of Navsats would need to be sent up.
  11. XXV: Rising Thunderstorm, Part 2 Boom Zoom The newly-established manned space program came not only with considerable engineering challenges, but also with the need to train the future astronauts for the situations they were to encounter. This program started in January 1960, and featured a large variety of activities, ranging from extreme g-forces training to more mundane tasks such as pressing buttons. Alongside the crew training program, the IASRDA soon found a need to develop and test a pressure suit that would ensure the survival of the occupant of the first manned spacecrafts. The human body is designed to operate better at altitudes below around 3000m, in the so-called physiologically-efficient zone. Above that altitude, the body enters the physiologically-deficient zone: there is an increased risk of hypoxia, of gases trapped in the body expanding, and of decompression sickness. Above roughly 10000m, breathing mixtures are required in order to get enough oxygen, while above 15000m, the pressure of the carbon dioxide excreted by the lungs is higher than the surrounding air pressure, therefore respiration is impossible. Pressure suits are thus required to compress the human body to aid in breathing. Pressure suits were not a particularly new concept, in fact, they were used even since the 1930s aboard high-altitude aircraft. The main issue with standard aviation partial pressure suits is that they only cover specific areas of the body, ergo, they are limited to a maximum altitude. The IASRDA would instead need to develop a full-body suit, which instead wouldn’t have such limit, and would protect the occupant of a spacecraft in case of sudden decompression even in the vacuum of space. The result of this endeavor was the IASRDA Aquarius Block 1A (AB1A) suit, derived from studies of the US Navy and the Royal Air Force, ultimately being visually similar to the Navy Mark-series pressure suits (with differences). The Aquarius Block 1A was incredibly compact and light (at just 10kg) for its capabilities, and wouldn’t limit the astronaut’s mobility as much as the other designs that had been considered. The suit was equipped with a closed-cycle breathing system, with oxygen entering through a hose at the waist of the wearer, and circulated around the suit for cooling, and exited through the helmet via either the opened visor, or a small hose in case the aforementioned visor was closed; the suit’s outer shell was made of aluminum-coated nylon, and the leather safety boots were covered in the same material, all for thermal control purposes. Each astronaut was provided with three suits: one for training, one for the eventual flight, and one to be used as backup. The AB1A suit was extensively tested before it would ever be used on a space mission, and one of these tests would be conducted through the Thunderstorm 3 mission; in which a crew of two would use the experimental aircraft to make a zoom climb to 30km altitude and beyond. Ultimately, it would be Commander Isaac Perry and Senior Captain Joe Mitchell who were chosen to fly the extremely perilous mission. Thunderstorm Program patch. The flight was scheduled for the mid-morning of September 22 1960, just days after the successful launch of Pathfinder 2 and 3. The aircraft that would be used was a modified version of the Thunderstorm, named Thunderstorm HA (for High Altitude). The only difference was the addition of an oxygen supply and extra batteries behind the cockpit, therefore apart from a slightly higher weight, it was completely identical to the base model. Image 19600922A. "Thunderstorm 3, ready for take-off" Take-off occurred at 10:04AM, in a particularly clear morning. They were followed by another Thunderstorm, flown by FLtn Sam McDonald and SpFC Thomas Lynn. Image 19600922B. Mitchell engages the afterburner and initiates take-off, the other Thunderstorm is circling above the Cape, taking photographs. The aircraft started a slow climb to 12900m, mostly to conserve fuel, with the two crewmembers only engaging the afterburner above 8500m to maintain a vertical speed of 20 m/s. Image 19600922C. "Passing 2000m, velocity still rising" Image 19600922D. "We're right behind you, Mitch" Image 19600922E. "Engaging afterburners, vertical speed dropping too rapidly. Altitude 8700m" The two aircrafts reached the determined altitude after 11 minutes; the crews then conducted a system check before accelerating to the maximum rated speed of Mach 2.621. Image 19600922F. "Afterburner at maximum rated thrust on my mark, McDonald... mark!" Image 19600922G. "At 532 m/s now; we need to get to 775" After reaching Mach 2.621, the two crews saluted each other, as only Mitchell and Perry would commit to the climb. A few seconds later, Mitchell pulled hard on his stick, and the Thunderstorm started rising. Image 19600922H. "See you two later at the Cape, stay safe up there!" Image 19600922I. "We're passing through 25km as we speak" Image 19600922J. "Vertical speed dropping to almost zero... God, it's beautiful up here! I can see the curvature of the Earth very well!" The aircraft reached an apogee of 31734m before the combination of lift and thrust wasn’t able to keep it airborne no longer. The crew started their long fall towards a “flyable” altitude. Image 19600922K. "Hold it steady Mitch. Pull it up slowly when you feel air pressure is high enough, don't force it just yet" Through extensive use of the airbrakes, Mitchell was able to stabilize the plane completely by 14000m, albeit pulling up to a steady 5.7gs in the process. The two then kept descended through the atmosphere and, half an hour after take-off, started returning to base. Due to limited fuel reserves, they weren’t able to rendezvous with the other Thunderstorm. Image 19600922L. "We're on our way back home. We did it, boys!" The two pilots landed safely after 1 hour 21 minutes and exactly 30 seconds since they took off. Mitchell later played those numbers at the lottery in the hope they would bring him fortune, but lost anyways. The flight altitude record established by Perry and Mitchell was incredible, and beat the previous one by more than two hundred meters, but wouldn’t last long, as just a few months later, in April 1961, they would be beaten by a Soviet aviator flying in a Mig-21. Nonetheless, the flight proved that the Aquarius Block 1A pressure suit worked fine, even in extreme situations, successfully protecting the wearer while allowing respiration. However, the pilots still found something to complain about, in this case, the difficulty of moving the head with the helmet on.
  12. XXIV: The Way to Progress, Part 1 Charting the Unknown With the successful mission of Explorer 6, the unproven probe core had finally been tested. It had performed excellently, adjusting course and generally keeping the spacecraft safe for the whole 5-day trip to the Moon. The design was ready for more demanding missions. The IASRDA had wanted to send probes to other planets for a long time, and the more powerful rockets, coupled with the new unmanned cores, meant that the dream would soon become a reality. Exploration of the interplanetary medium, as well as Mercury, Venus and Mars would be the objective of the Pathfinder Program. Logo of the Pathfinder Program, with the Earth, Venus, Mars and Mercury depicted. The IASRDA astrophysicists had calculated that the optimal time to launch something towards Mars would be in mid-September 1960, with Venus some months later. Since there was a lot of time before these “launch windows” would open, a preliminary mission was designed, to explore interplanetary space around the orbit of the Earth. A total of five missions were planned, one in heliocentric orbit, two towards Mars and another two towards Venus. In the end, the two Venus missions were scrapped to avoid overloading the newly built Deep Space Network. Schematic of the Pathfinder Block I series of probes. The Pathfinder Block I spacecraft was designed around the Explorer 6 probe core, albeit it was slightly different and had been stripped down of unessential material to lower the weight. The complete spacecraft weighed 245kg at launch, and was equipped with a large variety of scientific experiments. The probe carried an ion mass spectrometer, an orbital perturbation experiment, a Geiger counter, a micrometeorite detector, a thermometer, an infrared radiometer, and a magnetometer on a boom. Power was supplied through seven 7.88W solar cells. Attitude was controlled through four 24N, four-way, thrusters burning hydrazine, there were 53.6 liters of it stored on the spacecraft. Communications were handled in two ways: through a dish antenna, which was able to communicate up to a distance of 351Gm, with a maximum uplink capability of 768kbit/s, with a power consumption of 25W, this was the main way the spacecraft would communicate with Earth; and two low bandwidth and power antennae, these were the secondary comms. The weight of the spacecraft required the heaviest launch vehicle ever assembled by the IASRDA. Schematic of the Vega B upper stage. The Vega B upper stage was of similar design to the Vega A2. It was equipped with the same X-405H main engine, but the diameter of the tank had been widened to match that of the Prometheus: 3m (so the stage was actually shorter than the A2 variant). The extreme mass of the upper stage and payload meant that, in all cases, two Castors 1 solid boosters were required to lift the launch vehicle off the pad. Pathfinder 1, that would be sent to heliocentric orbit, would have a single X-248 kick stage, while Pathfinder 2 and 3, which would go to Mars, were equipped with a double kick stage of an X-242 mounted atop a X-248 in a very precarious assembly. Unfortunately, the development of the uprated versions of both the Arcturus and Alcor stages rendered the Vega stage almost obsolete, its only true usefulness being its wide diameter. The launch of Pathfinder 1 was scheduled for mid-July 1960, and ultimately the spacecraft would launch on July 14 from Launch Complex 2. Image 19600714A. Daybreak at the Cape, with the Prometheus-Vega standing by for launch. The rocket took off at 9:24 in the morning, under a discrete cloud cover, which would render attempts at tracking the launch vehicle during ascent close to impossible. Image 19600714B. Take off of the Pathfinder 1 mission! Notice the heavy cloud cove over the launch site. The Castors were separated at T+37, as the rocket was passing through the clouds. SIMULATION. The Castor solid boosters are separated once they are spent. The first stage burn went smoothly. MECO occurred at T+156, and separation occurred a few seconds later. SIMULATION. Staging occurs without issue. The second stage functioned perfectly, and third stage separation went well. SIMULATION. With the fairing decoupled, the payload is clearly visible. The Vega stage ignited as planned. SIMULATION. The Vega stage in operation. The stage inserted itself and the payload into a preliminary 185km parking orbit. SIMULATION. The Vega stage in its parking orbit. Two minutes later, the X-405H re-ignited to commence the boost towards heliocentric orbit. SIMULATION. The Vega stage fires again. After the main engine exhausted its propellant, the kick motor was ignited, not before having been spin-stabilized by the Vega ACS. After its burn was complete, the spacecraft was on the correct trajectory to interplanetary space. SIMULATION. Pathfinder 1 drifting in space around the Sun. Pathfinder 1 entered its heliocentric orbit seven days after launch, on July the 22nd. It was the first IASRDA probe to communicate with no issue from beyond the Earth’s sphere of influence. The probe orbited the sun in an orbit with an apoapsis slightly higher than Earth’s, and a periapsis slightly lower. It stopped communicating after 100 days, when its electrical system malfunctioned, but remains there to this day. The next step in the Pathfinder Program were the two Mars probes. The even higher delta-V requirements of these missions meant that not only the double kick stage was needed, but also that the Prometheus needed four Castors boosters attached to its side, the maximum it could support. Pathfinder 2 launched first, on September 16, 1960. Image 19600916A. Aerial image, taken by helicopter, of the Prometheus-Vega rocket that would lift Pathfinder 2. The launch took place in the mid-morning, at 10:01, from LC-2. Ignition of the LR79 was smooth and all four Castors were started with no issue. Image 19600916B. Lift-off! Image 19600916C. Aerial photograph of the Prometheus moments after lift-off. Image taken by Jean-Pierre Giraud aboard a IASRDA Thunderstorm. Separation of the solid boosters occurred with no accident. The core kept burning until it exhausted its propellant, at which point the second stage was ignited and separated. SIMULATION. Separation of the core and ignition of the second stage. The second stage worked perfectly as well. It now was time for the Vega to provide the last push to orbit. SIMULATION. The Vega ignites for the first time. Nearly 10 minutes after lift-off the rocket and payload were into a 185km parking orbit. Thirty minutes later, the kick program was activated, and the probe was on its way to Mars, although a series of correction maneuvers would be needed to bring the probe to an encounter. SIMULATION. Pathfinder 2 on its way to Mars. Pathfinder 3 launched a day after its sibling, on September 17, from Launch Complex 1 Image 19600917A. Lift-off of the Prometheus B-Vega B rocket carrying the Pathfinder 3 space probe. Despite a series of errors in the guidance of the Prometheus B-Vega B, the payload was safely inserted into a 185km parking orbit, and 30 minutes later was on its way to Mars. Pathfinder 3 would also require some maneuvers to properly intercept the Red Planet. SIMULATION. Pathfinder 3 leaves the Earth on its voyage to the Red Planet. The Pathfinder program was off to a great start, with three successes out of three launches. Pathfinder 1, despite the failure it suffered 100 days into the mission, had transmitted a large amount of data regarding conditions in interplanetary space. The two Mars probes were now beginning their 10-months trip to their destination, with, admittedly, very little probability of success, although many at the IASRDA were certain at least one of them would be heard of again. Announcement: This update is brought to you by the marvels of editing the Windows Registry for breakfast, after the latest update mysteriously corrupted all of the accounts on my computer, despite an entirely correct installation process. Also, this is why you make backups (take this as a PSA ). You may now resume your duties.
  13. XXIII: In the Pale Moonlight, Part 4 Moonbound Again While manned space exploration was the latest trend, for at least the following year the future of space exploration still laid in probes and satellites. These spacecrafts were rapidly becoming larger, with better capabilities and capable of carrying more experiments. Not only that, also new instruments had been made light enough, and resistant enough for space travel, for probes to bring them in the most remote places of the Solar System. With an interplanetary mission in the planning stage, the scientific teams of the IASRDA wished to test their expensive gear on a smaller scale, before sending them to another planet. That “smaller scale” request meant that another lunar mission was due. Schematic of the Explorer 6 lunar impactor. It was time to forget about the tiny probes that had been sent to the Moon up to that point, for the second-generation unmanned spacecrafts were larger than ever before. Explorer 6 would be the first probe (an impactor in this case) fashioned around a common core that would be the base for many 2nd gen satellites. Weighing a grand total of 276kg (compare that to the 45kg of Explorer 5), Explorer 6 carried a large variety of instrumentation, namely: an infrared radiometer (capable of sensing the variations in temperature on the surface of a celestial body from space), an orbital perturbation experiment (which allows to better understand the concentration of mass of said celestial body), a Geiger counter, a thermometer, an ion mass spectrometer, a magnetometer mounted on a boom, and a TV camera, in the hopes it would not fail this time. The probe was controlled by four 4-way 24N thrusters burning hydrazine, of which there were 53.6 liters on board. The spacecraft’s power was supplied by 12 7.88W solar cells. Communications with the Earth were handled through two 400Mm, 512kbit/s, 1.5W antennae. The satellite would be launched by a Prometheus B-Arcturus A, due to the probe’s mass. While a Prometheus B-Alcor A2 would actually be able to carry more payload to the Moon, the diameter of Explorer 6 meant it wouldn’t fit inside the 1.2-meter Alcor, instead fitting quite comfortably inside the 1.7m Arcturus. The launch date was set for April 4, 1960, as the spacecraft had to be sent into a direct ascent to the Moon. Image 19600404A. The Prometheus-Arcturus stack a few minutes before launch. Launch occurred in the mid-afternoon, at 16:37, although, due to the time of year, sunset was already approaching. Image 19600404B. Liftoff! The Prometheus B was an upgrade to the earlier A model, and its first stage was powered by two LR79-NA-11, which were rather more powerful than the -NA-9 version used on the Prometheus A. The first stage worked marvelously, and was separated at T+157 seconds. Image 19590404C. A tracking camera gets a good shot of the launch vehicle during ascent. The Prometheus B second stage was powered by a LR105-NA-5, also an upgrade over the A model, which would burn for 3 minutes and a half. This stage would provide most of the velocity to orbit. SIMULATION. The second stage after separation and engine ignition. The first stage is visible in the background. The last part of the orbital insertion and a majority of the TLI would be handled by the Arcturus A third stage. SIMULATION. The Arcturus A stage executing its part of the burn. After the Arcturus finished its part of the burn, the avionics shut down its engine and spin stabilized the X-248 kick motor, which was then ignited. SIMULATION. The X-248 performs the final orbital insertion. After its burn was finished, the X-248 was separated from the spacecraft, which was now on its way to the Moon. SIMULATION. Explorer 6 drifting towards the Moon. Explorer 6 performed a series of maneuvers during its flight to fine-tune its trajectory to the Earth’s satellite. SIMULATION. Explorer 6 performs a course-correction maneuver. The TV camera appeared to be working well this time, and it recorded several frames of the probe’s descent towards the lunar surface. It reached the Moon’s SOI by April 9. Image 19600406A. This photograph was taken just before entry into the Moon's sphere of influence. Image 19600409A. The Moon is still far away, even after entering its SOI. Image 19590409B. Approximately four thousand kilometers away, and counting. Image 19600409C. Surface features are starting to become visible. Image 19600409D. Image 19590409E. This was the last image transmitted by Explorer 6, taken approximately fifteen seconds before impact. The probe impacted that same day in the Grimaldi Crater. The mission was a complete success. The images received from Explorer 6 were some of the most breathtaking ever seen by man. They were not the only important data received, however. The Orbital Perturbation Experiment had demonstrated that the Moon has very irregular mass concentrations, at least where examined by Explorer 6. If this was true everywhere across the Earth’s satellite, any probe orbiting around it would be very short lived, unless stable orbits in fact existed.
  14. Hey guys, I'm finally back home and with a decent internet connection (and a keyboard, most importantly). @kewcet @The Dressian Exploder thank you very much for the kind words @Geschosskopf I've been able to hitch a ride on a weird spaceship where everyone dressed in red, yellow and blue uniforms; but at least they weren't Vogons. Also I sincerely hope the Earth doesn't catch fire at the end of this story; although I must admit that I was indeed trying to infuse Asimov's mojo into my designs, but I messed up and my notebook became sentient instead -- and now refers to himself as Isaac. Well, I'll need some time to make a couple of adjustments here and there, but in a few days we shall return to regular(-ish) posting! See y'all soon™!
  15. It is chonky indeed, but it’s supposed to be flown inside a fairing (much like the Centaur-T on the later versions of the Titan), so it is shorter than the D version, which would instead limit payload space (or require a longer fairing).