Captor Program: Exploring The Mun in 4x Scale.

[septemberWaves]

This thread is for my Captor program: a series of Gemini mimics designed for conducting Mun exploration missions. Of course, I'm playing in a scaled up version of the Kerbol system. Celestial bodies and orbital radii are increased by a factor of 4, and atmosphere heights are increased by a factor of 1.4 (there are also some other minor modifications to make things work better at this scale).

First, here is a post containing the testing phase of Captor 1. It has since had some updates but I'll get to those another time. Captor 1 is an approximation of the standard Gemini spacecraft that actually flew in reality. It can reach Kerbin orbit with about 1500m/s of delta-v remaining, but cannot reach the Mun on its own.

Below: first iteration of Captor 1 on the launch pad.

 

The next vehicle in the series is Captor 2 (below). It is launched on a significantly upgraded Titan launch vehicle, with even a modified Centaur stage. As well as adding the SRBs to turn it into a Titan III rocket, I had to make the entire vehicle longer to contain enough delta-v to reach orbit. Valentina and Maenna Kerman are the crew of this first mission to Mun orbit and back.

Spoiler

First stage ignition, booster ignition.

Liftoff.

Initial acceleration is quite high, and continues to increase until booster separation.

People familiar with the M.O.L.E. mod might notice that something has been added to the command module between the doors. That's an EVA parachute module which basically allows the crew members to eject from the capsule and parachute to the ground in the event that the abort sequence is activated.

Reaching maximum acceleration and maximum dynamic pressure.

Booster cutoff.

Booster separation.

This upgraded Titan core is propelled by two Vector engines. They have slightly lower thrust than the Moa engines of the original rocket, but the extra efficiency was more important for this vehicle.

Ascent is nominal.

First stage cutoff and separation, nosecone jettison, second stage ignition.

The second stage is an upgraded single-engine Centaur stage, which I am designating a Centaur 2 stage. A direct evolution from the one used on the Captor 1 launch vehicle, this one is powered by a Moa engine and has twice the fuel capacity.

Second stage cutoff as 105km apoapsis is reached. Due to the launch profile, the vehicle also currently has a 40km periapsis, and requires only a minor burn to circularize.

Circularizing. The Titan III upper stage only had 9m/s of delta-v remaining after this burn.

Launch vehicle separation.

The Captor 2 spacecraft is the majority of the orbital module of a Captor 1 spacecraft, directly connected to a modified 2-engine Centaur 1 stage. The Centaur 1 stage is augmented with extended monopropellant storage for the fuel cells and RCS, extended electric charge storage, two relay antennas, and a MechJeb core. The entire configuration of Captor 1 orbital module plus modified Centaur 1 stage is considered a Centaur-S service module.

Executing the Munar transfer burn.

Maneuver complete.

Approaching the Mun.

Correcting periapsis to 40km.

Circularizing. For some reason the spacecraft appears to be slightly unbalanced beyond what the reaction wheels can compensate for. The RCS is capable of maintaining the correct attitude during maneuvers however, so it is not a major issue.

Circularized in a 40km Munar orbit.

The orbit seen from the map view.

Maenna conducting an EVA as Valentina remains inside the spacecraft.

After some orbits, a maneuver is executed to return to Kerbin.

Leaving the Mun.

Approaching Kerbin.

Service module jettison before atmospheric entry.

Re-entry is successful. It was not planned to land this close to the KSC, but it is a nice surprise.

Parachutes deployed.

Touchdown speed: 5.5m/s.

Spacecraft landed with no damage.

 

Edited January 20, 2017 by eloquentJane

[Death Engineering]

Awesome! 

Captor 2 seems a bit tall. Is that because the parts were made for an unscaled Kerbin? Did you try out the ejection seats? I had a good giggle watching them bail and come down safely on their own chutes. I wonder how fitting a lander into 4x is going to look...    

[Kertech]

33 minutes ago, Death Engineering said:

Awesome! 

Captor 2 seems a bit tall. Is that because the parts were made for an unscaled Kerbin? Did you try out the ejection seats? I had a good giggle watching them bail and come down safely on their own chutes. I wonder how fitting a lander into 4x is going to look...    

I can't rememeber who said it (probably in the blurb for 64k) but ksp stock planets are a 10th of normal scale, however the parts are scaled for a 0.64 scale earth! I would always recommend trying a bigger world, once used to stock!

[Death Engineering]

8 minutes ago, Kertech said:

I can't rememeber who said it (probably in the blurb for 64k) but ksp stock planets are a 10th of normal scale, however the parts are scaled for a 0.64 scale earth! I would always recommend trying a bigger world, once used to stock!

I have an install on 64K with 1.1.2 (I think) and did an Apollo style moon mission with stock parts. It was interesting but since I play without any engineering assist mods (yes, I am one of those people), it was tricky getting the delta vee where it was needed. Agreed though that 1:1 Kerbol is a tad small. Perhaps I'll go down the middle like @eloquentJane and try 4x.  

[septemberWaves]

4 hours ago, Death Engineering said:

Captor 2 seems a bit tall. Is that because the parts were made for an unscaled Kerbin? Did you try out the ejection seats? I had a good giggle watching them bail and come down safely on their own chutes. I wonder how fitting a lander into 4x is going to look...

Captor 2 had to use a significantly extended fuselage because it needed to get an entire two-engine Centaur 1 stage plus the Captor spacecraft into a 105km orbit. Unfortunately the proportions didn't work out to allow me to use the same rocket core as the Titan II on Captor 1. I think 4x scale leads to slightly larger rockets than real ones (proportionally) but it still allows similar enough designs that I was able to fulfill the challenge requirements for the launch vehicles.

I have tested out the ejection seats (there's not much sense in integrating a launch abort system if you don't test it out). I think I'll stick with a launch escape tower on most of my designs, but the ejection seats are fun to play around with and perfect for a Gemini mimic.

I haven't quite got the landers figured out yet. To start with I'll be going for the minimalistic approach: a single very basic monopropellant lander with as little actual structure as I can get away with whilst keeping it intact as a single vehicle. Landing on the Mun at this scale takes about 1200m/s with a good thrust-to-weight ratio, and a similar amount to be safe. It's not too difficult to pack about 2700m/s into a particularly small vehicle if most of the structure consists of fuel tanks, and I have some pretty good monopropellant engines available courtesy of RLA Stockalike. Future systems will involve larger landers and similarly larger launch vehicles (I'll definitely end up needing a Saturn IB mimic for some of the larger payloads). I also plan to assemble a station and surface base, so that the kerbals have somewhere to go and also somewhere to practice precision landings (it'll also help with preparing my early Mun exploration infrastructure for my long-term career game, which is moving to the 4x scale system now that I've been forced to restart it).

 

Speaking of future plans, I've found that I quite enjoy making vague mimics of real/proposed spacecraft designs in 4x scale. I've decided that once I'm done with the Captor program, I'll move on to more advanced technology and some mimics of the Apollo program. It'll be a separate thread with similar goals, and if that Apollo Applications challenge is still up and running then I'll probably use the sequel thread for submissions to that challenge (assuming 4x scale and my mod list comply with their rules). But that's not likely to be for a while; I still have several things I'd like to do with the Captor program, as well as the other things I have going on.

 

3 hours ago, Kertech said:

I can't rememeber who said it (probably in the blurb for 64k) but ksp stock planets are a 10th of normal scale, however the parts are scaled for a 0.64 scale earth!

Having done some stuff in 6.4x scale, it doesn't seem like the parts are ideal for it. Perhaps if you consider diameters of real rockets then that becomes the optimum scale, but I've found that rockets in 6.4x scale tend to seem a lot bigger than real ones.

Edited January 20, 2017 by eloquentJane

[septemberWaves]

Kerbin Orbit Rendezvous

The next step for the Captor program was a crewed Mun landing. Valentina and Maenna Kerman would both be once again sent to Munar orbit, with Maenna landing on the surface of the Mun.

The mission uses two launches which will dock in Kerbin orbit. The first launch is the transfer stage and Mun lander, launched on a Titan III.

Spoiler

Ignition.

Liftoff.

Reaching maximum dynamic pressure.

Booster cutoff.

Booster separation.

First stage cutoff and separation, fairing separation. I realized at this point that I had forgotten to set the fairing to clamshell deployment.

Second stage ignition.

Second stage cutoff as 105km apoapsis is reached.

Circularizing.

Launch vehicle separation.

 

The next launch contains the crew.

Valentina and Maenna Kerman launch on a Captor 1. This has been modified since earlier launches. It now uses the updated launch escape system with parachutes instead of a launch escape tower, and it also uses a monopropellant fuel cell instead of solar panels for power generation.

Ignition, and liftoff.

First stage cutoff.

First stage separation, nosecone jettison.

Second stage ignition.

Second stage cutoff as 110km apoapsis is reached.

Circularizing.

Launch vehicle separation.

Executing rendezvous maneuvers.

Approaching the transfer stage.

Docking is successful.

Executing Munar transfer burn.

Approaching the Mun.

Circularizing in low Mun orbit.

Deploying the Mun lander.

Maenna moving to the lander.

De-orbiting.

Landing is successful.

Surface samples are gathered and a flag is planted.

Ascent.

The lander does not have enough delta-v to circularize due to an engineering oversight, so Maenna will have to use her EVA suit to complete the circularization.

Circularization successful.

The spacecraft executes several maneuvers to rendezvous with Maenna.

Once Maenna is back on board the Captor 1 spacecraft, the transfer stage is undocked from. It will be de-orbited once back in communications range.

Returning to Kerbin.

Leaving the Mun.

Service module jettison.

High g forces were experienced on re-entry, but it was otherwise successful.

Parachutes deployed.

Landing successful.

 

[septemberWaves]

Captor 3

Captor 3 is a new lander design based on the Captor spacecraft. It is designed to land both crew members on the surface of the Mun, after being transported there by a modified version of the transfer stage used in the previous mission. The Captor 3 spacecraft is launched on a Serket IB. Once again, Valentina and Maenna Kerman are the crew of this launch.

Spoiler

Ignition.

Liftoff.

Commencing gravity turn.

Breaking sound barrier.

Reaching maximum dynamic pressure.

First stage cutoff.

First stage separation, nosecone separation.

Second stage ignition.

Fairing separation.

First stage cutoff as 125km apoapsis is reached.

Circularizing.

Circularization complete.

Upper stage separation.

 

With the crew in orbit, the transfer stage can now be launched. The transfer stage is similar to the one used for transporting the Captor 1 spacecraft and open-cockpit lander to Munar orbit, but it has a slightly extended fuel tank, its engines are tuned for greater efficiency rather than high thrust, and it lacks the service bay that contained the lander. The transfer stage is launched on a Titan III.

Spoiler

Ignition.

Liftoff.

Commencing gravity turn.

Breaking sound barrier.

Reaching maximum dynamic pressure.

Booster cutoff.

Booster separation.

First stage cutoff.

First stage separation, fairing separation.

Second stage ignition.

Second stage cutoff.

Second stage separation.

The transfer stage engines must be used to circularize and perform the rendezvous maneuvers.

Circularization complete.

Executing rendezvous maneuvers.

Approaching the Captor 3 spacecraft.

This was a dangerously close approach, but thankfully it did not result in a collision.

Preparing to dock.

Docking successful.

 

With the two spacecraft successfully docked in orbit, the mission to land on the Mun can begin.

Spoiler

Executing Mun transfer burn.

The lander looks a little odd here because of a visual bug which causes shrouds to randomly render in the wrong place after unloading and reloading a vessel. I discover later that this bug can be solved by quicksaving and quickloading, but for a while the lander will have several floating shrouds around it. I don't think it detracts too much from the overall appearance though.

Transfer burn complete.

Approaching the Mun.

Executing orbital insertion burn.

The vehicle is placed into a 30km circular orbit.

After waiting for half an orbit to be on the light side of the Mun for the landing approach, the spacecraft prepares for de-orbit and landing.

TSE (transfer stage engines) ignition.

TSE cutoff. The transfer stage didn't have much delta-v remaining, but it was enough for the initial de-orbit burn.

Undocking.

DME ignition. The descent module has four vacuum-optimized engines, providing it with a high thrust-to-weight ratio on the Mun as well as good efficiency.

The view from inside.

From this point, the landing approach is actually my second attempt at landing. I accidentally shut down the engines too early on the first try. The positive of having to retry the landing from a quicksave is that it got rid of the strange bug with the shrouds.

Final landing approach.

Throttling down.

DME cutoff; landing successful.

The crew disembark.

Obligatory crew selfie with the lander and the flag planted.

It's now time for the crew to return home.

The crew return to the Captor 3 spacecraft and prepare for ascent.

AME ignition, stage separation, and liftoff.

The ascent module engine is identical to the four engines on the lander, though it provides a lesser thrust-to-weight ratio so the ascent is rather slow.

Once in orbit, the spacecraft can almost immediately begin the return maneuver. The landing site was chosen partially for this reason.

Beginning return maneuver.

AME cutoff. The ascent module does not have quite enough delta-v to complete the ascent burn, so the RCS on the command module must be used.

Ascent module separation.

With the return maneuver complete, the spacecraft leaves the Mun behind.

Two aerobraking passes will be required to sufficiently slow the spacecraft without enduring excessive g forces.

First aerobraking pass.

Approaching atmosphere for second aerobrake and landing.

Second aerobrake.

Aerobraking complete, drogue chute deployed.

Main chute deployed.

Landing successful. Recovery operations can commence.

 

[septemberWaves]

The Captor program is now being cancelled in favor of the Pyrope Exploration Program. Whilst the technology used by the Captor program has proven itself capable of conducting basic Munar exploration missions, it is only marginally able to succeed, and a need for new technology has been highlighted. Captor-era technology is also likely to be difficult to upgrade for exploration beyond the Mun, whilst the plans for the Pyrope Exploration Program look promising.