Dawn of the Space Age | The history of the Kerbinian Society for Astronavigation

[RKunze]

This is the record of my new career mode game in a JNSQ/Principia world with Kerbalism and SkyhawkScienceSystem. Because of Principia, the Kerbolar system will look slightly different from what would normally be expected in a JNSQ setup. The most obvious change is that Minmus is the inner of Kerbins two moons.

I am publishing these mission reports both here and on GitHub (mainly because I need someplace to put the images, and GitHub is convenient), and will link to the GitHub version of each story from the story title here.

Dawn of the Space Age

A history of the Kerbinian Society for Astronavigation

They finally made it.

Almost a decade after founding the Kerbinian Society for Astronavigation, after almost endless discussions, research, planning, more discussions, scrabbling for money, lobbying, convincing investors and sponsors, calling in all favors any of them were owed (and now owing quite a lot of favors themselves), they finally had a launch site and research center. A former aircraft test site, conveniently located in the middle of nowhere (but smack on the equator!), complete with runway, hangar (a bit decrepit, admittedly), a small office building and a shed (now serving as mission control and admin office), a barracks building (newly renamed to "Astronaut Complex", and their home for the forseeable future) and a couple of nissen huts clustered around another office building (the "Science Center"). Always optimistic, they changed its old name to "Kerbin Spaceport Complex" (and to be honest, that does sound better than "Aeroplane Research Site Four"), and spent almost all of the societies' remaining funds on a brand new rocket assembly building (planned for a bright future, and way too large for what they could actually build) and a tracking station. And, of course, a launch pad (to be brutally honest this time, really just a patch of roughly graded dirt hopefully far enough away from everything else that accidents could happen without causing too much damage).

Who they were? A bunch of eccentrics, convinced that it was possible to use rockets to not only leave Kerbins atmosphere, but to actually "fall around the world" and stay up in the skies forever. And to go even further, to Kerbins moons, to other planets, and even other stars! The "space fool Kermans", they were sometimes called (and yes, even though Kerman is a very common name, there were an unusual number of Kermans in the society). Wernher von Kerman. Jebediah Kerman (no relation to Wernher). Gene and Mortimer Kerman (cousins, but not related to either Wernher or Jeb). Max Kalier. Robert Krussel. And last but by no means least, Valentina Korova.

The founding members of the Kerbinian Society for Astronavigation.

And as of today — day one of year one of the space age, because of course they had started a new year count for the occasion, in good kerbinian tradition — they were officially in business. The business of guiding Kerbalkind to the stars, as stated in the societies' bylaws.

Edited July 30, 2022 by RKunze

[RKunze]

Year 1, Day 5: SR-1 "Mity Eaglet"

Five days after KSA embarked on their mission to guide Kerbalkind to the stars, their first rocket sits on the launch pad, ready to fly.

The "Sounding Rocket No. 1" (SR-1 for short). Nicknamed the "Mity Eaglet", because it basically consists of the newly developed experimental atmospheric guidance/landing engineering testbed ("Eaglet") bolted to the "Mite" solid rocket booster (nicknamed both for its size, and because it "might actually work"). A compromise — too small to get to space (actually, too small to get much higher than a modern airplane, let alone a balloon), and a solid fueled rocket instead of the potentially way more powerful (but alas, way more complicated as well) liquid fuelled engine the KSA was developing. But it could be built fast (and cheap, a not unimportant consideration given the state of the societies' finances), the data that would hopefully be gathered from the flight was needed, and expectations were high for the Kerbinian Society for Astronavigation to actually navigate something if not to, then at least toward the stars.

Prelaunch tests on the pad were successful: Telemetry recorded and transmitted, transmitter in good order (obviously), internal electrical battery nominal. All systems go, all personnel safely either in the observation bunker or in mission control (and spectators actually atop mission control, thanks to its flat roof and good view of the launch pad). SR-1 ready for launch.

Ignition! Launch clamps free! We have lift— KABOOOM!!!!

Not five meters off the pad, SR-1 blew up in a big fireball.

A "thrust instability", the failure analysis concluded some time later. And of course, a huge disappointment and a rather severe setback for the Kerbinian Society for Astronavigation.

But miraculously, the experimental atmospheric guidance/landing engineering testbed survived the explosion almost completely undamaged, and even manged to send back the flight data of the not-quite-one-second-long flight.

And miracle of miracles, the Experimental Engineering Group actually paid out the 2000 funds prize they promised for getting a rocket at least 200 meters off the ground! Nobody in the society knows why. Rumour has it some accountant at the EEG confused "above ground" and "above sea level". But nobody wants to investigate, really. Gift horses and all. Don't stir the sleeping dogs. At least, the society did not lose too much funds from the debacle (they actually turned a small profit).

 

Edited July 30, 2022 by RKunze

[RKunze]

Year 1, Day 16: SR-2 "Extended Eaglet"

The explosion of SR-1 led to some debates within the society. Note to give up, of course, but how to go on.

Valentina, Robert, Mortimer and Gene proposed a cautious course and to re-do SR-1, while Max and Wernher wanted to accelerate development on the liquid fuel engine and fly that on the next launch. Surprisingly, Jeb did not push for going all-out, but instead proposed a compromise: Do another flight with the Eaglet, but use a bigger — albeit still solid — booster. That compromise was readily accepted. One deciding factor might have been that the Experimental Engineering Group offered not one, but two new prizes: One for reaching the upper atmosphere, and another, very substantial prize for reaching space.

As a result, at midmorning eleven days later, the sounding rocket number two is rolled out to the launch pad. Of course, nobody calls it that - it is either the "SR-2" (because everybody loves acronyms), or the "Extended Eaglet" (because building the thing was exhausting enough that no one had the energy — or the inclination — to come up with a witty nickname).

SR-2 is not much different from SR-1: The "Eaglet" core — or rather "an Eaglet core", the original one that survived the SR-1 explosion turned out to have taken some damage after all and was no longer flight worthy — atop a solid booster. A "Shrimp", this time (because shrimps are a bit bigger than mites), but still basically the same: A tube filled with explosives, with a central hole where the fire would burn, and a hole at the end where the hot gas could escape.

The other modification worth noting was on the Eaglet core itself: Two more slots for material experiments, and increased data storage, in anticipation of a rich return of scientific and engineering data from the lower and upper atmosphere, and possibly even from space.

Prelaunch checks completed, launch site evacuated, all personnel accounted for. At 001/016 07:22:42, Gene Kerman in mission control issues the launch command

Ignition! Launch clamps free! WE HAVE LIFTOFF!!!!

The cheers from mission control drown out even the roar of the booster, as SR-2 lifts off the pad in a huge column of smoky exhaust.

As if fate wanted to compensate for the SR-1 disaster, the flight went off without a hitch. At an altitude of about 45 km, the booster burned out. It had been decided early on to keep the spent booster for a while, in order to profit from the added aerodynamical stability provided by the fins.

T+2:16. Booster separation at an altitude of 76350 m. As near to space as makes no difference — telemetry no longer reported any aerodynamic effects. And still climbing at a good clip.

Across the 80 km mark. SR-2 had officially entered space, as defined by the World Record Keeping Society (not that there was much difference to 76 km). Telemetry still trickled in, indicating that the onboard experiments were gathering data. The Eaglet had acquired a a slight rotation within the flight plane, but this would hopefully be stopped by aerodynamic forces once back in the atmosphere.

A couple of tight moments after the (expected) loss of communication with SR-1 on reentry, and then

Telemetry, Flight: Reacquired radio contact. SR-2 core still rotating, but dampened.
Telemetry, Flight: Parachutes deploying. Rotation dampening further.
Telemetry, Flight: Parachutes deployed in drogue configuration.
Telemetry, Flight: Parachutes fully deployed, rotation stopped.
Visual Observation, Flight: Confirm parachute deployment. We can see the Eaglet!

SR-2 "Extended Eaglet" is almost back to Kerbin.

Almost. But then:

Telemetry, Flight: Something is off with the parachute...
Visual Observation, Flight: Parachute collapsed! Repeat, 'chute collapsed!!
Telemetry, Flight: We lost contact!

Analysis of the last seconds of telemetry and the telescope images revealed a problem with the reefing cutters. Apparently, the small charges used to cut the reefing lines to go from drogue configuration to full deployment had damaged the canopy, which caused the parachute to tear later in the flight.

And they never found a single piece of SR-2. They searched, of course. But it almost seemed as if the Kraken — the mythological creature which according to seafarers' lore swallowed whole ships on the high seas — had swallowed SR-2 as well.

Edited August 3, 2022 by RKunze
Fixed dialogue formatting

[RKunze]

Year 1, Day 26: SR-2 "Extended Eaglet" revisited

Another launch, another — not, not really failure, much less debacle. Yes, SR-2 did not make it back, and valuable scientific and engineering data was lost. But SR-2 did fly, it did reach space, and it almost made it safely back to Kerbin. That gave the society the confidence to not only try another SR-2 launch in almost the same configuration, but to accept another challenge by the Experimental Engineering Group: Fly a vessel to space and recover it safely. After all, they had almost done it before.

The only difference to the first SR-2 mission was a slightly steeper launch angle, because telemetry from the earlier flight indicated that the time spent outside the atmosphere had been a bit too short to complete the materials experiment on board SR-2. Hopefully, the steeper launch angle would ensure enough time in space.

So, ten days after the first SR-2 flight, another SR-2 has been rolled out to the launch pad:

Ignition! Launch clamps free! We have liftoff!

It almost starts to seem like routine...

But alas, about thirty seconds into the flight:

Telemetry, Flight: We read unusual thrust values.
Flight, Trajectory: Are we still on course?
Trajectory, Flight: Slight deviation, still within error margins.
Flight, all: We are still go for the mission.

and some seconds later:

Telemetry, Flight: We read zero thrust, repeat zero thrust!
Visual Observation, Flight: We see an explosion!
Telemetry, Flight: We still have contact to SR-2
Flight, all: Mission abort, repeat, mission abort!
Flight, all: But let's try to recover the probe core if possible.

Almost two minutes later, SR-2 safely touched down not far from KSC.

Another failure! But at least not without a silver lining: At least the flight data and engineering experiments for the early flight phase had been recovered. And after a quick inspection, the Eaglet actually proved out still flight worthy. This made it possible to quickly mount it onto another booster, and attempt another launch on the same day!

Not without sacrifices, of course. Lunch, first and foremost — there was barely time to grab some snacks on the run as the whole society scrambled to mount the recovered probe on another booster and roll it out to the pad again.

But early in the afternoon, the re-built SR-2 is ready for launch again.

Ignition! Launch clamps free! We have liftoff!

This time, everything went smoothly. Booster burnout at T+00:59. Payload separation at T+01:43 (as before, the flight plan demanded to hold onto the spent booster after burnout for the added stability provided by the fins).

Apoapsis at T+03:07 and 97708 m — another first! Nothing kerbalmade ever went farther from Kerbin!

As on the first flight, the Eaglet probe acquired a slight rotation in the flight plane, which changed to moderate oscillations around the retrograde direction on reentry. These dampened out quickly after deployment of the parachutes in drogue configuration at T+06:10, and were negligible when the parachute deployed fully at T+06:41

And finally, at T+07:13, on 001/26 10:17:59 on the spot, the Eaglet probe safely splashed down into the sea, roughly halfway between the mainland coast and Welcome Back Island.

Finally. Success at last. The undeniable proof that it was possible to reach space in a rocket, and safely come back to Kerbin again (and another big prize from the EEG, which certainly helped to further the societies' goals).

[RKunze]

Year 1, Day 32: RAK-I or "shenanigans of engineers"

For the last ten days, Max and Jeb had been busy in their spare time on a mysterious private side project in the old airport hangar. Now, they were finally ready to present it to the world: The "rocket assisted kar number one", or RAK-I for short.

A tricycle built from spare parts (last but by no means least some old small airplane wheels left over from the previous tenants of the KSC) and powered by a bunch of cheap, small, solid fuel rockets fixed to a circular frame, its express purpose is to reach a speed of at least 200 km/h and break the existing speed record for wheeled vehicles of any kind.

On the morning of 01/32, RAK-I is rolled out to the old runway for a first attempt at breaking the land vehicle speed record. After an inspired game of rock-paper-scissors between Jeb an Max to determine who will drive the RAK-I, the winner (or loser, depending on point of view) Max takes the drivers seat and lights up the circle of rockets.

Thrust has been carefully controlled so that the thrust-to-weight ratio stay safely below 1 (at 0.9, to be precise). Nonetheless, the rockets quickly accelerate RAK-I, and as it passes the hangar, shortly before burnout, it reaches a top speed of 58.5 m/s. Over 210 kilometers per hour — new world record for wheeled vehicles!

Unfortunately, a bump in the uneven old runway, combined with a slightly heavy foot on the brakes on Max' part, conspired to throw a small wrench into the works. The left back wheel of RAK-I shortly leaves the ground, RAK-I starts to slide into a turn and finally rolls over, throwing Max out of the drivers seat in the process.

Fortunately, Kerbal heads are thick, though, and — apart from a short dizzy spell — Max stays uninjured. And on inspection, RAK-I proves to be undamaged as well.

A final photograph memorizes another successful feat of the Kerbinian Society for Astronavigation, even if not quite in their main field of endeavour.

[RKunze]

Year 1, Day 42: Pathfinder I

Finally, the big day. In the assembly building, the crew is busy with the final preparations before the very first attempt to launch an artificial satellite. Aptly named the "Pathfinder". Its goal is to test a hypothesis advanced by noted scientist Kristian Kirbeland, that Kerbin is surrounded by a "belt" of charged particles, held in place by its magnetic field (the fact that the Bloeting Aerospace Corporation offered a substantial amount of money to test that hypothesis might have influenced the decision for this particular scientific goal just a tiny bit).

In fact, this launch will have several firsts: The first rocket with a liquid fueled engine — the very engine that Wernher and his colleagues have been working on for some time now. The fist two-stage rocket. The first rocket that can (and will) be controlled in flight. And the thing that will control it — a "digital computer" — is yet another first.

In short, plenty of opportunities for things to go wrong. No wonder everyone in mission control is a tad nervous as Pathfinder I stands by ready to launch.

The launch has been scheduled for 08:30, because the plan is to stabilize the satellite by rotating it around its longitudinal axis ("spin stabilization", the boffins call this). And launching at 08:30 will make sure that the satellite arrives in orbit exactly at midday and thus will get the maximum possible sunlight on its solar cells (those are another first — as if there were not firsts enough already for this mission).

And of course, something did go wrong. The new liquid fueled engine — vastly more complicated than a solid rocket — failed to ignite and the mission had to be aborted with the rocket still on the pad.

The problem with the engine turned out to be relatively minor, fortunately, and was easily fixed. So, exactly one day later, Pathfinder I is ready for launch again.

Ignition! Launch clamps free! We have liftoff!

Shortly after liftoff, the automated program on the digital flight computer tilts the rocket a tiny bit over to the east.

At the same time, a failure of the second stage separation mechanism is detected. But fortunately, the engineers — being leery of all the new stuff on this flight — built in a redundant separator.

The remainder of the ascent guidance is left to gravity alone.

At T+02:14, the liquid booster stage burns out and is separated automatically by the guidance program. The second stage with the guidance hardware and RCS equipment continues on.

Fairings have been successfully deployed as well.

Shortly before apoapsis, the guidance program prepares the last — and most involved — maneuver: First, the rocket is turned parallel to the horizon to prepare the upper stage for orbital injection. As it is midday here over the ocean east of Welcome Back Island, this also turns the satellite – and especially important its photovoltaic cells — broadside to the sun. Then, the whole vessel is spun around its longitudinal axis to stabilize it in this orientation.

And finally, the flight computer ignites the orbital stage, triggers the reserve separation mechanism, and — mission fulfilled — shuts itself down.

The orbital stage — now again under direct radio control from KSC — continues on, accelerating ever faster...

... until it REACHES ORBIT! Kerbin now has a third moon!! An artificial moon!!!

That the last decoupler failed again and the new satellite stays stuck to the spent upper stage booster is of little consequence. The radiation experiment will work equally well with the booster attached. And — to quote Wernher von Kerman — "at least the failure has provided us with valuable data".

Pathfinder I ended up in a highly elliptical orbit around Kerbin, with an apoapsis almost half the way to Minmus.

And as it turned out, there was indeed a region of elevated radiation around Kerbin, just as Kristian Kirbeland predicted. In fact, the data indicated that there might even be two such "radiation belts", separated by a region of (comparably) lower radiation.

[RKunze]

Year 1, Day 81: Pathfinder II

The huge wave of popularity following the launch of Kerbins first artificial satellite was followed by a notable influx of new members for the Kerbinian Society for Astronavigation. Most of them supporting members, but quite a few decided to dedicate their time fully to the society. Most notably Gus Kerman — an experienced engineer — who took over responsibility for operations, and noted scientist Linus Kerman. Kermans again. Something about the society seemed to really attract people with that last name.

And other organizations took notice as well, and came up with ideas and plans how to use artificial satellites: For monitoring the weather, to create accurate maps of all of Kerbin, even to use satellites for communications, as if they were huge radio towers — suddenly, the possibilities seemed endless. And, of course, for pure scientific research. First and foremost, for further investigation of the newly discovered radiation belt (or belts?) around Kerbin.

For the next munths, three new satellites were planned: Pathfinder II and III to further investigate the radiation environment around Kerbin, with different instruments than Pathfinder I. And finally — commissioned and paid for by the Research Advancement Division, including a substantial advance — a satellite dedicated to the observation of large-scale weather patterns: The "Weather ImAging Satellite" or WIMAS (actually, WIMAS I — there were already plans for more).

The two new Pathfinders would be launched on a modified version of the rocket that successfully delivered Pathfinder I to orbit: The same "Sandstone" first stage, but instead of the conical interstage with integrated avionics and attitude controls topped by a "dumb" upper stage consisting only a simple solid booster, the payload, and a small fairing to protect the payload, the new version (called unimaginatively the "Sandstone/Satevis" after its main components) would use a more sophisticated upper stage (albeit still a solid rocket as those were more dependable) with integrated attitude control, and put the avionics core on the second stage. And employ a bigger fairing to protect both the payload and the second stage.

And finally, WIMAS I — which would be quite a bit bigger and heavier than the Pathfinders — would launch on yet another modification of this new launch vehicle: With an additional tank segment on the Sandstone stage, and no avionics on the Satevis upper stage because WIMAS I was big enough to accommodate a digital computer on the satellite itself, which could be used both for the launch and later on for precise attitude control in orbit.

The flight plan for the two new Pathfinders will be similar to that of Pathfinder I: Delivery into a highly elliptical, equatorial orbit that will hopefully cross the newly discovered radiation belt (belts?) around Kerbin. But instead of spin-stabilizing the second stage along the direction of flight at second stage ignition, the more sophisticated Satevis upper stage will orient its payloads axis normal to the orbital plane, and then spin up to stabilize the satellites' orientation. And finally, after separation from the payload, the Satevis stage will coast to apoapsis, orient itself prograde, and fire four small solid retro rockets to safely deorbit.

And now, 38 days after the historical flight of Pathfinder I (and exactly three minths after its first attempted launch), Pathfinder II sits on the pad, ready to implement this plan.

Ignition! Launch clamps free! We have liftoff!

The ascent through the atmosphere is almost routine now: Shortly after liftoff, the flight software tilts the Sandstone rocket over a couple degrees to the east, and then lets gravity and aerodynamics guide it. Alas (almost routine now as well), shortly after liftoff, telemetry reports problems with some of the stage separators. One should be no problem (like on Pathfinder I, there is a second, redundant stage separator), and the other should hopefully still work.

At T+02:12, the Sandstone engine cuts out as planned.

The empty stage is kept for a while, until it is safe to discard the fairing and expose both payload and second stage to the rarified atmosphere.

At T+05:09, the flight software aligns the Satevis stage for orbital injection, and triggers the ignition.

... but nothing happens. Ignition failure!

Dejected faces all around mission control. Without the upper stage, the mission is doomed, and Pathfinder II will inevitably crash down onto Kerbin again.

Ironically, the rest of the flight plan executes flawlessly: After detecting no more thrust on stage 2 (as if there ever was any!), the flight software orients the rocket normal to the orbital plane, spins up to stabilize the payload orientation, and decouples the payload. Even the flaky payload separator works!!

But nonetheless, without the second stage to boost it to orbit, both Pathfinder II and the Satevis upper stage burn up high over the ocean to the east of the KSC. And since this happens both in daylight and far out to sea, nobody even has the chance to watch and properly enjoy the fireworks.

After thorough investigation of the Pathfinder II telemetry records, it was decided to go on with the program mostly unchanged. Of course, the learnings from the investigation would be used to enhance the failed components and to hopefully make them more reliable. But other than that, Pathfinder III was still a go. And a copy of Pathfinder II would be built and launched as Pathfinder IV (even before WIMAS).

[RKunze]

Year 1, Day 89: Pathfinder III

Only 9 days after Pathfinder II, a new attempt at exploring the — still mysterious — radiation belt (belts?) around Kerbin is made. To that end, Pathfinder III carries a sophisticated ionization and static electricity analysis experiment which allows detailed measurements of the charged particles that supposedly make up these zones of high radiation that most scientists have started to call the "Kirbeland Belt" (Belts?).

A couple of minutes after noon on 001/089, Pathfinder III lifts off the pad at the Kerbinian Spaceport Complex:

The flight — guided by the automated program installed in the "Satevis" stage aviation guidance unit — starts out picture perfect: Liftoff, roll to correct orientation, pitchover maneuver, smooth transition to a zero-lift turn.

Further ascent, including some serious acceleration after passing the 20 kilometer mark (and having burnt most of the fuel on the first stage).

And finally — just as the heat from friction in the thin but still noticeable atmosphere starts to get a bit much for the fairing — main engine cutoff at 42 km above the ocean, exactly as planned.

As with the launches before it, the spent first stage and the fairing are carried on for a bit, both for protection of the payload, and to help keeping the rocket oriented along the flight path.

At an altitude of 70 km, the fairing is jettisoned.

Shortly after that, just as the upper stage separates from the spent booster stage, things start go wrong again: First a decoupler failure — but the backup decoupler that engineering insisted on did fire. And then one of the two tiny rocket motors meant to shove the upper stage away from the spent booster stage failed. But the other one still provided enough thrust to get the upper stage clear of the booster. And finally, something seemed off with one of the batteries providing the electricity for the guidance computer — but there were still enough reserves to complete the mission.

Because of the pileup of near-fatal failures so far, and the fear that upper stage ignition might still fail as it did for Pathfinder II, the mood was a bit tense in mission control.

And the debate among a couple of spectators — which could be heard perfectly in the whole control room — as to wether the avoidance of a catastrophic failure so far was due to good planning or just plain luck did not really help. It did lead to an immediate ban of all spectators in mission control though — much to the chagrin of the participants.

So, as Pathfinder III drifted to apoapsis, you could have heard a pin drop in mission control. And when the Satevis upper stage engine did light off at apoapsis as planned, the cheers from mission control actually triggered an experimental new seismometer way over in the science center.

There was another problem — a thrust instability — during the burn, but again, not fatal.

And the rest of the first part of the flight went of as planned again: Orient the craft normal to the orbital plane in order to get sun on the solar cells on Pathfinder III, spin up the craft to stabilize the orientation, release Pathfinder III to start its scientific mission, and finally shut down the avionics guidance core on the Satevis upper stage to conserve electricity.

The second part of the launch — deorbiting the Satevis upper stage by firing another set of tiny solid rockets at apoapsis — was still several hours away. So while the science team got busy setting up Pathfinder III for the first measurements, the team responsible for the Satevis stage went to the astronaut complex cafeteria for some well earned snacks.

In line at the kaffee dispenser, Max (who did handle telemetry for this launch) asked

Say, Gene, did you notice the drop in signal strength from the Satevis after separation of Pathfinder III?
Sure, that is expected — just look at the specs for that puny builtin antenna in the Alpha-AGU, and compare it to the Pathfinder III antenna.

Having got their kaffee (they already had snacks), Gene an Max migrated to one of the cafeteria tables. Max seemed deep in thought, and — instead of paying proper attention to snacks and kaffee — started scribbling on a napkin.

A couple of minutes (and an absent-minded bite of Genes snack) later:

Gene, we may have a problem here.
Why?
Well, according to this, we will lose contact with Satevis about halfway to apoapsis
Yes, looks like it — but why is that a problem?
Because we need to restart the guidance computer by radio signal for the deorbit maneuver. And we can do this only a couple of minutes before apoapsis, or the batteries won't last long enough.
———— !!!

The ensuing, hastily assembled emergency brainstorming session came up with a plan:

• wait as long as signal strength allows to get as far along the trajectory as possible
• restore power to the guidance computer, and immediately send a signal to shut down the main guidance program, but leave the vessel orientation subroutines active.
• manually set the orientation target to prograde.
• as soon as the orientation stabilizes, send an override signal to manually fire the retro rockets.
• hope that this maneuver will lower the periapsis far enough that atmospheric drag will eventually deorbit the Satevis stage.

One hour and 10 minutes after liftoff, signal strength dropped dangerously low and the emergency plan was executed. And three minutes later, tracking confirmed that Satevis was indeed now on a suborbital trajectory, with a periapsis of 74 km.

And careful observation and tracking over the next couple of days confirmed that the almost negligible friction caused by the rarefied upper atmosphere was indeed sufficient to lower the apoapsis of the — now dead and inert — Satevis stage and its orbit would eventually decay enough so that it would burn up in the atmosphere as planned.

Meanwhile, Pathfinder III started its scientific mission. And preliminary results indicated that it was indeed radiation belts, plural.

And the analysis of the now so-called "antenna incident" finally concluded that the root cause had been a simple copying error — someone had accidentally used the antenna rating for the Pathfinder probe for calculating the radio reception range of the Alpha-AGU after separation from Pathfinder III. The recommended measure was to tighten up the review process for further mission plans.

Edited September 27, 2022 by RKunze

[RKunze]

Year 1, Day 93: Pathfinder III debris reentry

After more than three days in space, the orbit of the spent upper stage from the launch of Pathfinder III decayed far enough that tracking predicted final reentry into Kerbins atmosphere within the next 5 hours.

As predicted, at around 11:00 — late afternoon at the KSC — the spent Satevis stage reentered Kerbins atmosphere, a bit east of the KSC.

And painted a fiery streak across the afternoon sky. Bright enough to be seen even in daylight.

But — contrary to the expectations of most — the debris did not burn up. Instead, it continued on over the sea, and finally crashed down into the ocean well east of Welcome Back Island.

Edited October 2, 2022 by RKunze

[RKunze]

Year 1, Day 100: Busy days at the KSC

Only 100 days after the Kerbinian Society for Astronavigation built its first rocket at the so called "Kerbin Spaceport Complex", the place was a beehive of activity. Almost living up to its grandiose new name, even.

The successes of the the KSA had sparked a huge interest in space flight and space exploration all over Kerbin. And the inevitable failures and mistakes (including the infamous "antenna incident") were seldom talked about even in the media, at least partially thanks to the newly appointed PR director of the society, Walt Kerman (yes, yet another Kerman).

In consequence, several other institutions wanted satellites of their own, for a number of different reasons and projects.

A cooperation between meteorological institutes from universities across Kerbin managed to convince the "Research Advancement Division" (an organization dedicated to the "advancement of science" in general and well funded by a conglomerate of commercial interests and wealthy — in some cases very wealthy — individuals) that a satellite (or better yet, multiple satellites) dedicated to studying Kerbins atmosphere would indeed advance science quite a bit (and also offer considerable commercial opportunities).

The department of astrophysics at a small (and up to now pretty unimportant) university went into a cooperation with a major industrial player to fund a satellite for observing the sun. Speculations as to how they managed this ran wild for quite a while, but finally it turned out to be the rather simple fact that the CEO of said corporation was an alumnus of said university, and had both the means to finance the research and the inclination to do so.

And finally, the venerable Kerbographic Society — the very institution responsible for mapping Kerbins oceans and most of its land masses back in the age of sail — embarked on a huge new project: Mapping not only Kerbin, but eventually all major bodies in the Kerbolar system. The project would be handled by the newly founded Scientific Committee on Advanced Navigation within the Kerbographic Society.

So, a mere four munths after its first launch — and despite the fact of ongoing construction at the vehicle assembly building itself — the KSA was busy preparing not only one, but four new satellites for launch, all on the now tried and (mostly) true Sandstone/Satevis launch vehicle:

• Pathfinder IV (the replacement for the ill-fated Pathfinder II) was almost completed and scheduled to launch within the next 18 days.
• The first satellite dedicated to weather observation — with the rather uninspired name "weather imaging satellite one", or WIMAS I for short — was already mated to the "Satevis" second stage, and the "Sandstone" first stage was in final assembly.
• The first satellite for SCAN (named "KERMIT", officially as an abbreviation of "Kerbin mapping - initial topography", but according to persistent rumour actually after the main character in the favorite puppet show of the youngest grandchild of the chairwoman of the Kerbographic Society) was in final preparation for installing it on its "Satevis" stage.
• And finally, work had already begun on the "Kerbin Orbit Sun Observatory".

[RKunze]

Year 1, Day 120: Pathfinder IV

To avoid a recurrence of the infamous antenna incident, measures had been taken for Pathfinder IV: On the hardware side, a long(er) range antenna was retrofitted on the Satevis stage. And on the software side, the flight plan had been changed to keep Pathfinder IV attached to the Satevis stage until apoapsis instead of separating directly after orbital injection — mainly to take advantage of the solar cells on Pathfinder IV to keep the Satevis' batteries from draining (and maybe even recharge them a bit) on the long way to apoapsis.

All of this had taken a bit longer than planned. But finally, on 001/120 at 06:30 in the morning, Pathfinder IV sits on the pad, ready for launch.

Ignition!
Launch clamps free!
We have liftoff!

Pathfinder IV roars into the morning sky.

At an altitude of just above 40000 m, and just passing over Welcome Back Island, the Sandstone tanks are empty and the main engine cuts off.

Just one minute later, at 70000 m over the ocean, fairings and the spent Sandstone booster are jettisoned.

After coasting to its (temporary) apoapsis at 95 km, the Satevis SRB ignites as planned and hurls Pathfinder IV into its final orbit.

After Satevis burns out, the guidance program orients the whole vehicle normal to the orbital plane to catch as much sunlight on the solar cells as possible, spins it up to stabilize the orientation, and shuts almost every system down. The sole exception is a single radio receiver listening for a wakeup signal.

While Pathfinder IV coasts to its final apoapsis at just below 10000 km,the launch crew repairs to the cafeteria for a well-earned break for snacks and kaffee (thankfully, sans impromptu emergency planning sessions this time), where they meet the science crew — who will be responsible for Pathfinder IV after separation from Satevis — enjoying a leisurely breakfast.

At midday, everyone is back in mission control, and the launch crew sends the signal that powers on the guidance computer on Satevis again.

At T+02:49:14, the guidance computer reboots, detects that it is no longer on the launch pad, and proceeds to separate Satevis from Pathfinder IV. The launch team hands over control of Pathfinder IV to the science team.

After delivering its payload, the spent Satevis stage aligns itself prograde again, coasts to apoapsis, fires four small solid fuel retro rockets and shuts down. Exactly as planned.

Just a little push, a mere 22 m/s ΔV. But enough to make sure the spent booster will burn up in Kerbins atmosphere instead of cluttering up the sky above Kerbin.

Meanwhile, the science crew takes control of Pathfinder IV, and immediately gets busy preparing it for it scientific mission: Measuring gamma rays in space over Kerbin.

[RKunze]

Year 1, Day 132: WIMAS-I

Not even one minth after the launch of Pathfinder IV (12 days, one hour and 56 minutes, to be overly exact), another Sandstone/Satevis launcher sits on the pad. Ready to launch the first weather imaging satellite — or WIMAS-I for short.

Tension is high in mission control, because this launch again has a number of "firsts":

• Instead of launching into a highly elliptical equatorial orbit as in the previous missions, WIMAS-I will (hopefully) launch into a low, circular, polar orbit (so that it can eventually observe the weather all over Kerbin).
• WIMAS-I is much heavier and much more complicated than the previous satellites. It even has a computer built in, and this computer can even be reprogrammed in flight!
• In order to accommodate both the more massive satellite and the added Delta-V needs for a polar orbit, the Satevis stage will not have a dedicated controller aboard. Instead, the flight software for the launch phase will run on the WIMAS computer, and will be replaced remotely with the software for station keeping and scientific observations once in orbit (because — powerful as it is — the WIMAS computer nonetheless has not enough storage space to hold both the launch and the orbital software).

Especially the last point makes the launch team nervous. But the alternative — haul both WIMAS-I and the tried-and-true Satevis control module into orbit, each with their own computers — simply exceeds the mass budget for the Sandstone/Satevis lifter.

In order to maximize the illuminated area of Kerbin that WIMAS-I will observe on half of each orbit, the launch is scheduled for noon. At exactly 09:00:00, mission control gives the launch command.

Ignition!

Launch clamps free!

We have liftoff!

The Sandstone booster carrying WIMAS-I roars into the slightly overcast sky, and — for the first time — pitches north (and even a little bit west) instead of east.

The adapted flight software automatically adjusts the azimuth direction so that the final orbit will have an inclination of 90° — at least, that is what everyone im mission control hopes.

At the usual altitude of round about 60km, the fuel of the Sandstone booster is exhausted and the main engine cuts off. The new azimuth control software has worked perfectly so far.

At an altitude of 65 km, fairings are separated to expose the Satevis upper stage, and the spent Sandstone booster is jettisoned. Almost routine. But this time, the big island that the mission just passed is not Welcome Back Island.

WIMAS-I atop the Satevis stage coasts to an Apoapsis of 95 km. The extra batteries on the Satevis are needed to feed the power hungry computer during launch.

Shortly before reaching apoapsis, the Satevis upper stage ignites as planned.

In contrast to previous missions, this time — instead of just pointing prograde and hurling the payload as high as possible — the flight software makes sure that the apoapsis does not increase too much. And it cuts off the engine as soon as the orbit is circular (which is possible thanks to the ingenious engineers at Bluedog Design Bureau who came up with a system to stop a solid rocket before it runs out of fuel).

After reaching an almost perfect orbit (94 by 97 km, with an inclination of almost exactly 90°) the flight program cuts of the Satevis engine, and triggers both the small explosive charge that separates WIMAS-I from the Satevis and a set of eight small, solid, retro rockets on the Satevis that will deorbit the Satevis upper stage.

The launch team in mission control takes a collective, relieved, deep breath. Their job is done, and flawlessly. After handing control of WIMAS-I over to the payload team, the next to last item left on the agenda for the launch crew is to watch the — now uncontrolled — Satevis stage deorbit on the telemetry monitors.

The spent Satevis stage may now be uncontrolled, but definitely not out of control. The push from the retro rockets has lowered the periapsis — exactly as planned — just enough that it will reenter the atmosphere shortly after passing the north pole, paint a fiery streak over the northern ocean and either burn up shortly before reaching the equator (probably) or fall into the ocean a bit south of the eastern tip of an arid equatorial coastal mountain range (not as probable, but possible).

In any case, it will provide spectacular fireworks for a small crew of local radio (and space!) enthusiasts which are currently sitting high on a peak in said arid mountain range on behalf of the Kerbinian Society for Astronavigation, crewing the so called "off-site tracking station" (which consists of a portable — barely — antenna dish and radio, a portable — just as barely — generator, and a small cluster of tents) that provides the telemetry data currently scrolling over the monitors at KSC.

Meanwhile, the payload team gets to work. The first item on their agenda is to replace the launch flight software with a program that will keep the satellite oriented so that its top — covered with solar panels — always points to the sun (the sides are also covered with solar panels, but that is mainly a precaution to make sure that WIMAS-I does not immediately run out of electricity if it is not pointing at the sun).

The newly installed station keeping software boots up, detects that WIMAS-I is way out of alignment, and fires both RCS and reaction wheels to correct the error.

As soon as the axis of WIMAS-I stabilizes pointing to the sun, the station keeping software proceeds to spin it up to exactly 5 rpm. Fast enough to stabilize its orientation, slow enough to not blur the camera images.

From now on, the station keeping software will run in an endless loop, wake up every minute, check orientation and rotation speed, correct errors if necessary (using just the reaction wheels if the error is small enough, conserving the RCS fuel for unforeseen circumstances), and go back to sleep again. This will typically just take a few seconds, and leave most of the resources — especially the electricity produced by the solar cells — free for WIMAS-I's primary task: Observing the weather on Kerbin. From Space.

And already the first image sent back to the science team proves out to be sensational: Not only a clear image of wispy clouds over the northern ocean off the polar ice shelf, but a an equally clear image of the northern aurora!

As the launch team heads out of mission control to get to their last checklist item for the day (which is, of course, to repair to the cantina for a well earned celebratory snack), they hear in passing the preliminary discussions between the WIMAS-I and the Pathfinder science teams about a joint research program to further study the influence of the radiation fields around Kerbin on its atmosphere, focusing on the northern and southern aurorae.

Edited November 26, 2022 by RKunze