[MISSION LOG] Kerbifornia Institute of Technology

[Ben 9072]

Mission: SETH I/Topograph III

Mission Objective: Launch a satellite to examine Laythe for possible habitation sites based on elevation, proximity to natural resources, and kethane content.

Launch Vehicle: SETH I Launcher

Payload: Laythe Orbital Observation Unit

Mission Outcome: Mission was resoundingly successful and went without incident. The device made it from Kerbin to Jool with copious amounts of fuel remaining, so an aerobraking maneuver was unnecessary. However, to be conservative, a multiple-pass aerobraking maneuver was executed to bring the craft into a polar, low-level orbit around Laythe. Data collection subsequently commenced.

Mission Highlights:

Device and launcher on launch pad:

Entering Jool's SOA:

Aerobraking in reinforced aerodynamic pod:

Sunrise over Laythe:

Satellite in orbit:

Data collection beginning:

[Ben 9072]

Alright, I should be completely caught up on mission updating, so from here on out, all missions should be current.

[Ben 9072]

Mission: Oceana I

Mission Objective: Determine the density of Kerbin's oceans, and determine if the fluid comprising them is, in fact, water.

Launch Vehicle: Oceana I Launcher

Payload: Mk1 Command Pod and Mk16 Parachute

Mission Summary:

An experiment was carried out to measure the density of the fluid comprising Kerbin’s oceans, presumably water. This simple experiment consisted of a rocket with a droppable mass that was easy to find the volume of, namely, a Mk1 command pod and a parachute module. Images of this launch are attached.

Device on Launch Pad:

Payload deployed:

To begin with, the density of water can be expressed as

Where rho = density, m = mass of a floating object, and V = volume of water displaced. An experiment was run to determine the density of Kerbin’s oceans based on the height of a floating object. The object chosen for this task was a Mk1 Command Pod due to its simple design as a conical sphere segment. A single parachute was put on top to avoid casualties, though this was not submerged, so volume was unaffected. The combined mass of the command pod (m=800kg) and the parachute module (m=100kg) was 900kg. The task, then, is to find the volume of water displaced.

Reading from the Mk1 Pod .cfg file, we obtain that the height of the pod (the distance between the two attachment points) as 1.047m. Since the attachment points are tiny and small, respectively, their diameters are .625m and 1.25m, so their radii are .3125m and .625m, respectively. Given this information, all needed information was solved for (see Fig. 1).

Fig. 1: Dimensions of command pod.

The only direct measurement taken was the 40 degree angle of the vertex of the cone, taken from the model file. Since the edge of the bottom of the pod very closely approximates a section of a sphere, it is near-orthogonal to the vector pointing to the convergence of all lines toward the center of the imaginary cone surrounding the command pod. Thus allows us to calculate the slant height from the arc containing the top attachment node to the edge of the bottom curve as equal to the height, namely, 1.047m. The vertical height from the top attachment node to the edge of the bottom curve, therefore, is 1.047cos(20) = .984m. Note that the 20 degree angle is used instead of the 40 degree angle, since the line of reference is the central axis. The height of the bottom curve to the edge of the bottom curve, then, is 1.047-1.047cos(20) = .0631m.

Fig. 2: Pod at rest.

We now attempt to express a cross section of a rotation of the command pod as two functions. Referring to Fig. 2 – an image taken after the lading pod had come to a complete rest, we visually calculate the slant height submerged to be .5467m by multiplying the slant height (1.047m) by the ratio of pixels submerged to total pixels on the pod. The height submerged, therefore, is the height of the bottom curve to the edge of the bottom curve plus the height submerged, which is .5467cos(20)+.0631 = .577m.

Fig. 3: Cross section of floating pod.

Now that we have obtained the height submerged, which will serve as our initial and final limits of integration, we must find the functions to express the cross section of the capsule. The slant from the bottom curve to the line of the water level will be very simple to solve for. But we examine the curve function first. As the curve on the bottom approximates a sphere, its cross-section is a circle. Thus, if expressed as a section of the circle tangent to the y axis (touching the origin), the whole function takes some form

Since the section of the circle forming the edge of the pod encloses a 40 degree angle, the angle from the edge of the pod edge to the center is 40/2=20 degrees. Thus, the height of this, when rotated sideways, as shown in Fig. 4, is 1.25/2 m, as the base is a small attachment point. So, rsin(20)=.625m, so r=.625m/sin(20)= 1.827m. Therefore, the function takes the form

Fig. 4: Cross section of area of revolution.

Note that there will be some error/discontinuity in the circle function meeting the linear function, as the bottom of the pod does not perfectly approximate the sphere. However, since the vast majority of the volume is stored in the conical section, this will be attributed to an overall experimental error. The limits of integration on this function are from 0 (the bottom of the pod) to .0631 (the height intersection of the bottom of the pod to the edge of the bottom).

For the second function, the calculation is much simpler. It is simply the slant starting at (.0631, .625) running horizontally for a distance of .5467cos(20) = .5137m with a slope of –tan(20). Equivalently, this is the function starting at (0, .625) running for .5137m. So, the function is equal to

And the equivalent limits of integration will be from 0 to .5137. (The original limits were from .0631 to .577, but this is equivalent to the function shifted until it touches the origin, and will yield the same volume.)

Thus, the volume will simply be

Note that since the function describing the spherical estimate of the capsule is an underestimation and has an intersection point less than .625m, the volume displaced must be AT LEAST 1.429 cubic meters, and probably hovers around 1.6 or 1.7.

Thus, returning to our original formula, we have:

The density of water at 18.665 deg C – the average temperature of Kerbin (thanks to the International Space Science Organization for this data) is 998.5 kg/m^3. The density we have found for the fluid comprising Kerbin’s oceans is at most 629.5 kg/m^3, meaning the disparity between the densities of water is at least 369kg/m^3, a difference too large to easily be attributed to experimental or graphical error. This leads to an interesting disparity as to whether Kerbin’s oceans are actually made of water. Furthermore, note that the density of water increases as salinity increases, so the disparity would only grow if the oceans were salty on Kerbin. Further investigation is pending.

[Geschosskopf]

Kerbin's oceans are very strange beasts so I'd be cautious of drawing too many conclusions from the fascinating data you collected above. For instance, solid steel I-beams float like styofoam egg cartons, just barely touching the surface, whereas hollow capsules sink at least 1/2way down. Also, if your experimental hydrofoil breaks up and a piece with a fin remains alive, it will roll over so the fin is pointing straight up in the air, instead of the weight of the fin acting like a keep and keeping the body part upright.

I've come to the conclusion that there must be INCREDIBLE surface tension, but that this also extends to depth. IOW, Kerbin's oceans are more like Jello than liquid. This probably explains why there are no waves or tides on Kerbin.

[togfox]

Nice analysis. I'd have chosen something other than a conical command pod - like an empty cylindrical fuel tank. Perhaps the same calculations can be re-run and cross checked that way.

[Brotoro]

I think what we are seeing here is the weird physics of flotation in KSP.

[Ben 9072]

Kerbin's oceans are very strange beasts so I'd be cautious of drawing too many conclusions from the fascinating data you collected above...I've come to the conclusion that there must be INCREDIBLE surface tension, but that this also extends to depth. IOW, Kerbin's oceans are more like Jello than liquid. This probably explains why there are no waves or tides on Kerbin.

That's an interesting thought, and it also lends credence to the idea that Kerbin's oceans are not made of water, since surface tension is a result of the chemical structure of water. I'll think about ways to test that, though I'm doubtful the programmers added surface tension into the game.

Nice analysis. I'd have chosen something other than a conical command pod - like an empty cylindrical fuel tank. Perhaps the same calculations can be re-run and cross checked that way.

I originally was planning on running the experiment by lowering a fuel tank via winches into the sea, but it kept destroying the tank. Cylindrical objects would have been easier to use, however, if they had not constantly been destroyed.

[tntristan12]

Are you accounting for the weight of the kerbal inside the pod, and the parachute*ejector on top?

[Geschosskopf]

There's a mod that will help with this study. I forget whether it's the newest version of Firespitter or TT's Modular Multiwheels, but one of them now includes a part that will make your vehicle spawn in the ocean off the end of the runway. No more having to get from dry land to the "water" . Look at the descriptions of both mods at the Spaceport; whichever one it is says it's got this part.

Of course, the usual "drop test" on start-up occurs, same as on the runway. But so far I haven't had anything explode from this when spawning in the ocean.

I've been tinkering around with boats lately (but NOT using the boat parts mod), which is why I'm convinced of the extreme viscosity of the oceans, or maybe their surface tension. That stuff is like molasses, preventing both speed and maneuver. If the actual hull is in the "water", you won't move more than about 5m/s no matter how many rockets you have pushing it. It IS possible to make hydrofoils which I've gotten up to about 80m/s, but I find these completely unable to turn even with many rudders both above and below the surface. And my only "successful" submarines (as in being able to submerge at all) require big rockets constantly pushing them down. Turn the rockets off and they instantly shoot back up to the surface.

Amazing as it sounds, the only thing that really moves and maneuvers reasonably well in the ocean is an EVA Kerbal. I speculate that Kerbals are amphibious creatures specially evolved to move through whatever the oceans are made of, but that this gift doesn't apply to their creations.

[Ben 9072]

Are you accounting for the weight of the kerbal inside the pod, and the parachute*ejector on top?

I accounted for the mass of the parachute ejector. To my knowledge, the program does not include kerbals' masses in the calculations until they go EVA, sort of "spawning" them rather than accurately calculating the mass. However, the mass of a Kerbal is .03125 (from this study), so the error it would provide would be minimal compared to the 1.1 mass of the pod and chute.

There's a mod that will help with this study. I forget whether it's the newest version of Firespitter or TT's Modular Multiwheels, but one of them now includes a part that will make your vehicle spawn in the ocean off the end of the runway. No more having to get from dry land to the "water" . Look at the descriptions of both mods at the Spaceport; whichever one it is says it's got this part.

I'll look into that, thanks!

[Ben 9072]

Mission: ISSO 1/Topograph IV

Mission Objective: Map the surface of Minmus in response to an ISSO assignment

Launch Vehicle: Munar Mapping Satellite Launch Vessel

Payload: Munar Mapping Satellite Mk1

Mission Outcome: The mission was a success. Since the satellite launched was an out-of-date version lacking the ion engines for post-separation orbital corrections, the two final stages were not separated, so as to keep the polar orbit almost perfectly circular. This mission was done in conjunction with the Interplanetary Space Science Organization.

Mission Highlights:

Vehicle after launch:

Orbital burn to Minmus:

Approaching Minmus:

Mapping Minmus:

ISA Map:

Polar Map:

[Ben 9072]

Mission: IKOS Reconstruction I

Mission Objective: Rebuild IKOS following its destruction

Launch Vehicle: SpaceTrans Mk2

Payload: IKOS Core

Mission Outcome: Following the destruction of IKOS in the .21 update, a new, part-optimized model was constructed. IKOS Mk2 will also serve as an orbital fuel and supplies depot for the future SETH program for Laythe colonization. As a step towards a reusable space program with the implementation of recovery systems for flights, all non-oversized pieces of IKOS Mk2 will be deployed using the SpaceTrans vehicles designed by Kertech. (Possibly to be exhibited along with other vehicles in a future Kertech Showcase thread in the spacecraft exchange.)

Mission Highlights:

SpaceTrans shuttle with station payload:

Shuttle in flight:

In parking orbit:

Deploying the station core:

Reentry:

Landing at KSC:

[Ben 9072]

Mission: KPS I

Mission Objective: Launch three Kerbostationary communications satellites around Kerbin.

Launch Vehicle: KPS Launcher

Payload: KPS Communications Satellite

Mission Outcome: Success. The satellites were launched into almost completely noneccentric Kerbostationary orbits. Future commsat missions are planned to have at least two satellites in line of sight from any point on Kerbin at any given point in time.

Mission Highlights:

Initial Launch:

Circularizing:

Current state:

Head on view:

[Ben 9072]

So it's been quite some time since I've played KSP, and unfortunately, not all of the mods I was originally using survived the multiple updates. I remade a lot of my previous save file from scratch using only stock parts, but eventually gave into temptation and installed B9 and procedural wings. I think I'll try only using those from now on.

[Ben 9072]

Mission: SpaceTruck 3 Development

Mission Objective: Develop a reusable spaceplane capable of orbiting station parts to IKOS Mk5 after the loss of the previous SpaceTruck generation.

Launch Vehicle: SpaceTruck Mk3

Payload: IKOS Mk5 Habitation Extension

Mission Outcome: Success. The habitation module was docked to the asteroid attached to the space station, and the vehicle was landed back at KSC with a small amount of fuel left over.

Gallery:

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