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The JAMES (Jool Atmospheric Measuring Satellite) Mission
The first Kerbal mission of exploration to the gassy outer planet had been a tremendous success. The JEFF probe had completed all of its intended objectives, and had outperformed the expectations of its designers. The success of the mission convinced scientists and planners that larger, more sophisticated probes and missions could now be sent to study the planet. It also helped bring increased funds into the program, as the team behind it had demonstrated their capacity for success. This allowed for the possibility of more missions and gave the planners designing these missions more options to work with. The extra money also permitted the development and construction of new probe designs and launch vehicles.
The JEFF mission had been more of a technology demonstrator than a dedicated science mission. Though JEFF had returned a wealth of data, the scope and quality of its instruments was quite limited, and many of Jool’s secrets remained hidden. There remained an enormous amount of possible areas and things to study and observe, and the data already collected didn’t begin to touch the depths of knowledge which waited to be discovered. Scientists and astronomers studying Jool were already beginning to compete for instruments and experiment space aboard the probes. Scientists from different fields were eager to study different aspects of Jool, and thus lobbied to the mission planners for different mission objectives. Some scientists were interested in the planet’s interior and atmosphere, as the gassy planet was unlike any other world in the Kerbal solar system. They hoped for a mission which would study the planet, its composition, and its weather in greater detail. Others were more interested in Jool’s moons, which the JEFF probe had revealed to be much more complex, unique, and full of surprises than had been expected. A number of scientists wanted to shift attention from Jool itself onto Jool’s moons, which they felt might hold even more dramatic secrets and discoveries. With the program’s future secured, planners began to seriously consider it’s timeframe and mission schedule for the first time. The needs and desires of scientists and astronomers were taken into consideration along with the technical accomplishments which needed to be achieved.
The first of these was achieving orbit around Jool. Any complete scientific study or observation would need to have long-term access to Jool, and this could only occur while in orbit. Doing this, however, was much more challenging of a maneuver than JEFF’s flyby had been. In order to get into orbit, a probe must carry enough fuel to be able to lower its velocity around Jool and become trapped in its gravitational sphere of influence. The great distance to Jool means that much fuel has already been spent. Though probes had achieved orbit around the inner planets before, they were much closer to Kerbin than Jool and thus easier to get to. Ensuring that a probe would have enough fuel to get to and then achieve orbit around Jool was a major challenge which would need to be overcome. The alternative was aerobreaking in Jool’s atmosphere. A probe flying through the dense atmosphere could be slowed enough to be placed into an orbit. This, however, could seriously damage the probe, and was thus unfavorable as an option. Planners also wanted to orbit and then land on one of Jool’s moons. This would be even more complex a maneuver than a simple orbit around Jool. With this in mind, it was decided that a probe designed to orbit, study, and image Jool would be sent first. The next probe would orbit and study one or multiple of Jool’s moons. A third probe would then orbit one of Jool’s moons and deploy a lander, which would land on and study the moon from the surface.
Plans for a science platform spacecraft had been in the works since early in the JOOL program, beginning shortly after the program was announced. Near the same time JEFF was flying past Jool and returning the first observations of the planet, a basic design for such a spacecraft was nearing completion. Once more money came into the program and planners decided upon the program’s mission schedule, the instruments and experiments to be carried aboard the spacecraft could be more selectively chosen. As it had been decided that the next mission to Jool would study the planet’s atmosphere, a number of specific instruments and scientific equipment designed for that purpose were installed. Complex cameras and imaging devices were also placed on the spacecraft. The complex space maneuvers needed to get into orbit around Jool required extra fuel, so tanks were installed on the probe’s propulsion unit. Once designs were complete, the probe took a number of months to construct It was during this time that it was designated the Jool Atmospheric Measuring Satellite, or JAMES. JAMEs was installed aboard a new rocket designed specifically for the JOOL program, the Modular Attachment Transport, or MAT.The JAMES spacecraft. Attached to the engine on the bottom are a number of fuel tanks, used to place the craft into orbit around Jool. The upper stage above, with its four engines, allow for small maneuvers. The spacecraft’s four solar panels provide power. Along the top of the spacecraft are the numerous instruments and imagers used to study Jool. The array at the top of the craft is used to communicate with mission controllers on Kerbin.
The spacecraft was launched from Kerbal Space Center at 4 am, and went smoothly. The MAT rocket performed as expected, and placed the spacecraft into orbit 80 km above Kerbin. For 5 days and 19 hours the spacecraft stayed in orbit around Kerbin, activating and testing its instruments on the planet and its moon. The readings taken by the atmospheric instruments were compared to data collected by other satellites orbiting Kerbin, and were found to be identical. Mission controllers were convinced that JAMES was functional and ready to study Jool. The practice of activating a probes instruments in flight started with the JEFF probe, and became policy for the JOOL program. It was easier to discover a problem with a spacecraft and attempt a repair while in orbit around Kerbin than around Jool. 5 days, 19 hours, and 15 minutes into flight, the first stage reactivated and fired for 30 seconds, sending the spacecraft to Jool. It separated from the spacecraft, and the second stage burnt for another minute to place the probe into an encounter trajectory with Jool.JAMES blasts off from Kerbal Space Center aboard the MAT rocket at 4 am on a mission to study the gassy outer planet of Jool.JAMES in orbit around Kerbin, testing its instruments and equipment.
JAMES’s launch, orbit around Kerbin, and transfer to Jool had gone perfectly, as had been the case with JEFF. The mission planners and scientists who had designed and constructed JAMES and its flight plan were incredibly proud of their continued success. However, soon into JAMES’s flight to Jool, a problem was detected. For some reason, the spacecraft was slowly losing power, even though all of its primary systems and instruments had been put into a hibernation mode for the journey. A series of preliminary checks did not reveal any technical problem with the probe, and planners began to fear the worst. It was possible that the craft had been damaged in flight by a micrometeoroid, or that the craft’s wiring and electrical equipment had been installed improperly. These possibilities would not be detected by any checks performed by planners on the spacecraft. Scientists and engineers quickly began to search for the problem and come up with a solution before the probe completely shut off.
Fortunately, the problem was quickly recognized: the solar arrays were not receiving any sunlight, and therefore not powering the spacecraft. It was determined that the probe was facing away from the Sun, thus explaining the solar arrays’ inability to receive its rays. However, the arrays were supposed to rotate to face the Sun no matter what direction the probe was facing; for some reason, they were locked in place. In order to remedy this, mission planners decided to rotate the spacecraft to face the Sun as it journeyed to Jool. This was an easy solution, but it was also an unwanted one: rotating the spacecraft required precious thruster fuel which mission planners had hoped to used to maneuver JAMES into different orbits around Jool.
104 days into flight, 99 days after JAMES had left Kerbin orbit, the spacecraft’s engine reactivated and burnt for 4 seconds. This brought JAMES into a closer encounter with Jool, which would help it enter an orbit around the planet more easily. Then, 14 days later, the engine was fired again for another 13 seconds, which brought JAMES even closer to the planet. Finally, after 300 days in flight, the JAMES spacecraft entered Jool’s gravitational sphere of influence, and snapped its first images of the planet.JAMES captures its first images and takes its first measurements of Jool as it approaches the giant gassy planet.
As JAMES approached the planet, it began taking readings and measurements with its suite of instruments. When it reached its closest point to Jool, 5481 km above the planet’s top cloud layer, the probe’s engine activated and burnt for 2 minutes, slightly longer than was expected. This placed JAMES into a slightly elliptical orbit, with its farthest point from Jool almost crossing the orbit of Laythe, the innermost moon. The stage carrying JAMES’s extra fuel and engine then decoupled from the spacecraft, having been completely spent.JAMES’s engine fires as the spacecraft flies past Jool, placing the probe into a slightly elliptical orbit around the planet.JAMES’s orbit around Jool, which almost intersected the orbit of Laythe, Jool’s innermost moon.
Now in orbit, JAMES began a more intensive study of the planet and its atmosphere. The data sent back to scientists and astronomers on Kerbin was incredible valuable, and helped them vastly expand and refine their understanding of Jool. The probe studied the “Great Wisp”, a weather event on Jool which was visible from space. JAMES revealed this to be a massive storm, and continued to observe and measure the storm for the remainder of its mission.JAMES studies Jool’s “Great Wisp”, a major storm brewing on the top of the planet’s cloud system.
In addition to JAMES’s study of Jool, an effort was made to study and image the planet’s moons. JEFF had discovered that Laythe, the innermost moon of Jool, had a substantial atmosphere, and JAMES’s instruments were perfectly suited for the measurement and study of that atmosphere. JAMES’s close orbit with Laythe routinely brought it near the moon, and scientists made most of these encounters by focusing JAMES’s attention on it. It was discovered that Laythe’s atmosphere ends 52 km above the moon and is slightly less dense than Kerbin’s. The temperature on Laythe was found to be less than 0 degrees Celsius, so it was reasoned that the bodies of liquid on the moon must be comprised of something other than water. Attention was also given to Jool’s other moons, though JAMES’s distance from them meant that a more complete study and photography of them was impossible.While in orbit around Jool, JAMES studies Laythe during its closest encounter with the moon. Jool’s more distant moons, Vall and Tylo, are imaged by JAMES. Vall, which had not been extensively studied or imaged by JEFF, was determined to be a large, icy world.
JAMES remained in orbit around Jool for a number of months, continuing to produce new data and discoveries for astronomers and scientists. Curiously, the spacecraft started sending back status reports which indicated that its orbit around Jool was degrading. Mission planners calculated that JAMES was being pulled out of orbit around Jool by Laythe every time the probe had a close encounter with the moon. They realized that the probe would soon escape Jool orbit, be captured by Laythe, and flung around the moon. There was much concern that JAMES might either smash into the moon or be sent flying into interplanetary space. Some planners wanted to use the last of JAMES’s fuel, which was storied within the spacecraft, to restore orbit around Jool. However, some astrophysicists, having spent days calculating possible trajectories and orbits for JAMES, realized that it could easily be placed into a stable orbit around Laythe as it was being flung past the moon. Once in orbit around Laythe, JAMES could study the moon in greater detail, while still taking observations and measurements of Jool. This option was lobbied for by some mission planners, who felt that placing JAMES into a stable orbit around Laythe permitted the continued study of Jool, and by the scientists who had hoped for a dedicated mission to study Jool’s moons. After much debate, it was decided that this option would be chosen.A view of JAMES’s orbit around Jool being altered by an encounter with Laythe.
As JAMES was flung around Laythe, its four small booster engines ignited and burnt for 45 seconds, expending all of the probe’s remaining fuel. Fortunately, this burn put JAMES into a stable orbit 140 km above Laythe’s surface. The spacecraft’s proximity to the moon allowed it to conduct much more detailed studies of its atmospheric composition, its surface, and its interior, and JAMES returned a wealth of information on Laythe to Kerbin. Meanwhile, as mission planners had hoped, the probe’s study of Jool continued unaffected. The further distance from Jool proved to be a benefit for the study of the planet, because JAMES was able to more accurately and completely measure Jool’s magnetosphere.JAMES in orbit around Laythe.JAMES snaps a picture of Laythe and Jool together in the same frame. This image would later be considered one of the most iconic and moving of t hose taken during the JOOL program.
The JAMES mission had, like JEFF, been an enormous success. Despite technical problems early in the mission, the probe managed to perform beyond all expectations, and returned a huge amount of highly valuable information and data on Jool and its moons. The mission initially intended to orbit Jool but, in a twist of fate and luck, the JAMES probe was able to also be placed into orbit around one of Jool’s moons, Laythe. This feat helped mission planners and scientists design the later JOOL program missions, which they wanted to have orbit Jool’s moons as well. The success of the JAMES probe, and the continued success of the JOOL program, made it one of the most popular and accomplished programs of space exploration the Kerbals had ever developed. Mission planners now turned their eyes and efforts to the more complex, more challenging, and more promising missions to Jool which were yet to be sent.