Show your Spaceplane in RSS: Real Solar System

[gilflo]

Hello guys

I didn't found any topics on Spaceplane in RSS mode, so I create this one

I am playing RSS (Real solar system) on KSP 1.7.3, but not R . It is yet a big challenge to send a rocket or a spaceplane in orbit as you have to reach Mach 25 or more than 7500m/s to be free from gravity.

Stock engines stock are not an option to send a rocket or a spaceplane in orbit and I use Real Scale booster engines and OPT mod engines. SSTO is impossible.

What I decided is to create a Stratolauncher, then have a spaceplane on the top to launch it at the Stratolauncher ceiling at the quickest speed to achieve orbit.

For planes OPT engines are very powerful and we can reach 48kms as ceiling. Then launching speed depends on the StratolauncherTWR and 5000m/s are reachable .

To achieve orbit climb you can't rely on gravity turn, and you must use the PrimerVector method that Mechjeb is using in RSS/RO which is to adapt your speed vector to be as near as possible from your apogee (less than 15s is great) to achieve your orbit in only one burn......That allows to save a lot of DV.

Atmospheric autopilot mod is a good mod to fine tune your speed vector while piloting your spaceplane to orbit.

 

My first spaceplane is designed to reach the moon orbit. I built a ascent and a descent stage behind the cockpit to make this stuff detachable from the spaceplane core. So, the cockpit will land on the moon, then leaving the descent stage on the moon, it will climb back to orbit and  dock to the spaceplane core. The shorter spaceplane will fly back to earth 

Meanwhile, using FMRS, the Stratolauncher will land to base. The base is Kourou.

 

Here is my trip to Moon in RSS with The Stratolauncher, renamed StratoRaptor and the Spaceplane Raptor whose cockpit will undock and descent on the moon.

We need to reach 25, around 7500m/s to leave Earth, which is impossible with an SSTO, even with OPT engines

That's why I create the Startoraptor launching the Raptor Spaceplane. Weight of the raptor in charge is around 153T

The 4 hybrid engines of the Raptor leaves 13000DV range in vacuum  provided you give them 50 electric units/s during engines run

The cockpit with its descent and climbing stages decoupling from the Raptor core are the Moon lander. Here is the service bay with 20 NearFututreElectrical RTGs to help the Hybrid engines in close cycle mod

Here is the Stratoraptor 995T bicockpit plane with 80% fuel. 12 OPT J61 engines giving a TWR >3 at the engine ceiling around 48500m. That allows More than Mach 15 at launch

Take off and heading 117° to be on lunar plan

Climbing 70°, acceleration around 15000m and mach 2.5

Leaving 37000m under acceleration, we try to stay a near as possible from apogee: see the MechJeb PrimerVector concept in RSS/RO in the RSS RO wiki (very interesting)

 

43500m; Mach 13.5 less than 5s from apogee, great acceleration, we should launch at more than M 15

Launch at more than mach 15  StratoRaptor being in sub orbital flight with engines shut

that 's an awesome optimal climb for the Raptor reaching 5000m/s a 52000m

Approaching orbit with more than 10000DV

Lunar transfert calculation

Meanwhile with FMRS,we come back to the StratoRaptor which is 1200kms far from base. The best return flight to spare fuel is the following: vertical dive engines shut, then engines relight under 30000m, inverse Immelmann to climb to orbit

we begin climb on the back around 13000m

Then half barrel roll

and climb to suborbital

A second suborbital climb is necessary to avoid fuel shortage

the shortest possible approach

we try the runway which is very hard with such a big aircraft. Use of Atmospheric autopilot is a great help

On the ground

Here in lunar orbit, undocking the lander

Lander retrobreaking

Gear down

fine landing

Crew goes out to plan a flag

Climbing back to cockpit for departure

The descent stage stays on the Moon

climbing to a 45kms orbit

Back view from tanks and climb engines

Calculation of docking point

approach and angular alignment on the fuselage

Cockpit docked and well aligned, Raptor is now shorter as we left the descent stage on the moon

7000 DV left for earth return

 

2mn HD vid for cockpit separation and landing

https://youtu.be/Oub2VP7PagM 

2mn HD vid Cockpit docking after moon climb

https://youtu.be/K45A36cMzak

 

815 DV for earth injection

Then 1800 Dv to get  8000kms apogee with 160 perigee

Then still 1500Dv to circularize at 160kms  break enough for re entry

South burn aligng with the launch base, it's 1300 DV more

due to overheat speed brakes are destroyed

lighting engines in air breathing mode

long final on Kourou runway Kourou which is an island like all other bases in RSS (I think it's a bug from the mod which is not updated for KSP 1.7)

Landing fascing East, too long, pull up and landing facing west

long landing and stop at the very end of the runway

Conclusion

I am happy with Stratolauncher to launch spaceplane. It works very well with OPT engines. Maybe it could be a good idea to gat a back inflatable shield on the spaceplane to spare aerobraking fuel

 

I am planing a bigger Stratolauncher to launch a bigger spaceplane including cargo hold for a rover and more DV

[EveMaster]

Very impressive mission!

Have you tried a lower TWR for the upper stage? I found it most efficient for the upper stage in RSS/RO to have a TWR of less than 1 and finish the circularization well after apoapsis with a antiradial component. My initial apoapsis is higher than the final apoapsis with this approach.

Have you considered doing multiple aerobraking passes to save delta v?

Could you please post a link to the wiki entry about the Primer method? I could not find it.

Edited October 18, 2019 by EveMaster

[gilflo]

Hello

in fact to see what is the best guidance on RSS, this is here
https://github.com/lamont-granquist/MechJeb2/wiki

and the best thing to do is built a rocket to see that working with mechjeb

and as you say twr<1 is better on upper rocket stage with cryo engines using LH2 and Oxydyzer.

But here it’s a Space Plane with OPT mod and last updated OPT engines and tanks that work with LH2 don’t work with Tweascale, there’s a big mess for the time being, and i did not updated OPT mod for this reason.

 

 

[gilflo]

About the rocket and this particular ascent guidance mod in RSS, you can look my vid for the Apollo Anniversary.

On the french KSP we had a Challenge for this and I built a Saturn rocket to send Apollo 11 on the moon.

you will see the ascent and the lower TWR on second stage. You ll find also other vid of the mission

On Mechjeb the selected ascent mod is Primer Vector, wich is different from the link i gave you,  but it looks like mechjeb has been updated and the method name was changed, but i think it is the same method as all other climb datas remains the same..

look at the Time to Apoapsis during all climb on the upper left HUD and you will understand how it works

 

 

 

Edited October 18, 2019 by gilflo

[EveMaster]

Your apollo 11 is well done, I like the combination with real world footage. The orbit is very precicely circular and you time to apoapsis is always very low.

When I played RSS, I did not have problems with Korou launch site in the ocean. I think I played on KSP 1.5, but I'm not sure.

I always used lh2 and liquid oxgen for the upper stage of my rocket and for the ejection burn in RSS. I have not used OPT engines. I guess they are some near future engines that are more powerfull and better suited for space planes.

I have not built space planes yet in RSS. But I have sent a Kerbal to the surface of the Moon and back as well as an unmanned Missions to the Mars system and one to map all Galilean Moons for biomes and height.

For landing and ascent on the Moons of Mars was the only time I used mechjeb landing and ascent guidance. I don't know which method used, but it did not matter much because of the low gravity. I will have a look at the advanced mechjeb settings for ascent.

[gilflo]

Hello guys

I introduce the  StratoMaX : This RSS Stratolauncher is able to launch 315T or more at a speed of more than 5500m/s (around mach 17) at its ceiling of 48500m. Playing RSS Earth we need 7600m/s to reach orbit

This is a 1600T plane with OPT MK2 central cockpit and 20 OPT J61 TurboRamjet "Starwaster" engines (diameter 2m50) , giving a TWR >3 at the 48500m ceiling

Here is the monster

Screen of the engines

Many many wings, winglest and stabilizers as we need to pilot this thing at 48500m with a nearly 0 m/s vertical speed before launching. 

Here is the Martian Shuttle, with 2 ejectable rockets, that allow the shuttle to reach orbit with nearly its full 16000DV range. The 4 engines Shutlle are working on LF taken in the stratolauncher tanks to help for climb, but they switch off long before reaching the ceiling.

At launch, they are relight in Closed Cycle and run with the 2 RS 25 from RealScaleBoosters taking their fuel from the lower ejectable tanks so that the Martian Shuttle range can be maximum at orbit

There is a rover with 2 seats in the cargo hold and it is ejected during Martian ground approach and it lands with its own parachutes. Mars approach is performed retrograde, parachutes get out when speed is lowered under 800m/s by engines around 25000m.. Then approach is completed with engines and chutes in retrograde. Near the ground 2 back landing struts are supposed to help the back touch and give an impulse to lower the shuttle on the ground on the gear....Touchy but it works!

The 2 big RS 25 and the big tanks are the only thing abandoned in space

Screen of the Martian Shuttle mounted on the back of the StratoMaX. The 2 big rockets are strut to the shuttle via a center pilar and 2 Staging docking ports, the first one to launch the Shuttle, the second one to leave the rockets...

Once the Shuttle is in parking orbit, the StratoMaX, having flown along South American coast from Kourou to launch in orbital plan, has got just enough fuel to make a right turn to reach the coast and land somewhere in the land as it is not possible to have more than 1 airport...

The StratoMaX can also land on the sea very well; if necessary.

[EveMaster]

Impressive craft, @gilflo. Can the Martian Shuttle also come back to LEO from the surface of Mars or even land back on Earth? If so, I'd like to hear a mission report about it.

[*MajorTom*]

I do not build spacecraft on the "technologies of the future." But I wondered  here whether it is possible to build a single-stage return vehicle on our RD 171 MV.

Well, as it were, a kind of shuttle-spacecraft turned out in which engines do not burn out, but only fuel tanks.

So, well, like a one-step approach to an orbit with RO and our Russian  latest engines is potentially possible and you can even get 5 tons to LEO (okay, let's say 6) if you make it unmanned taking into account the wild overloads of 11 G (but I calculated by the money ... by the weight of the burned fuel and the cost of the tanks ... but it's such a pleasure - comparable to the launch of a one-time Proton and the whopper will be the size of a heavy Falcon). 

But ok... pics of most kerbalized RSS+RO 1 stage spaceplane.

 

 

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ps^ also create this model for suborbital flight  ( with a tourist rescue system, but honestly the fuel price - I didn’t think so I can’t say how efficient it is to fly on an AL 31 fm and not just on rocket engines)

 

 

 

13G -just a ridiculously sharp maneuver, and so usually everything is fine

Edited October 24, 2019 by *MajorTom*

[gilflo]

Well playing with FAR is much more complicated, I tried on Kerbin and I liked it, but on RSS wow!!!

10 hours ago, EveMaster said:

Impressive craft, @gilflo. Can the Martian Shuttle also come back to LEO from the surface of Mars or even land back on Earth? If so, I'd like to hear a mission report about it.

That's the point: The Martian shuttle is designed to take off from Mars and land back to Earth. With 16000DV from Earth orbit, it must be possible.

What I am trying now is to Built a runway with KerbalKonstruct to have the StatoMax land on it after launch....So I must launch in the Mars plane and as near as possible from the South America coast if I want to be able to land the Stratomax on a runway and not in the sea....

[gilflo]

RSS Mission to Mars - Part 1

Here we take off to be aligned with Mars plane

climb to 48000m

Around 48000m the StratomaX engines shut down due to lack of oxygen. We light on the 4 engines of the Shuttle in rocket mod and at launch the 2 RS 25 engines from the jettison able tanks to orbit are lighted.

The shuttle climbs to orbit using 6 engines taking fuel from the jettissonable tanks

Then the 24 ullage engines (4 groups of 6) that avoid any collision at launch, are ejected

circularization on reaching apogee

Recovering the StratoMaX at more than 1000 kms from base, we have not enough fuel to fly back

A special runway built for StratoMax in the south of Brazil is at 400kms on our right. we need to descent to be able to make the right turn.

We just need a bit of sub orbital flight to reach it

runway in sight

leaving base leg to final appraoch

Nearly landed, short of fuel

on the runway

Jettissoning the orbital fuel tanks. Notice that the FMRS has recovered the StratoMaX as soon as he has landed

Here is a short 4 mn HD vid to see the launch

 

Edited October 24, 2019 by gilflo

[gilflo]

RSS Mission to Mars - Part 2: Landing on Mars

Here is the DV Map to Solar system: We need around 6300 DV to there and  to land

High atmosphere is around 120 kms over Mars and we perform some aerobraking at 50 kms and it was quite efficient

Then we use the engines to establish a 120 kms orbit

The Martian Shuttle will brake on and land on retrograde

Here is a small HD vid to see how we proceeded: Rover was ejected during landing procedure

 

Then Kerbals went out to drive the Rover. At this point there's a bug on this OPT cockpit that can take 5 crews: we launched 5 crews and we were 2 on arrival....but not a problem

I forgot the ladder on the rover but the Kerbal manage to climb and drive the rover under the nose of the shuttle so that his colleague can jump on the rover

Driving to the nearest hill to plant a flag

And here we are

There some science instruments on the rover but unfortunately there's no scientist.

Now it's time to board

 

 

Edited October 29, 2019 by gilflo

[gilflo]

RSS Mission to Mars - Part 3

 

We landed on Mars with 8761 DV Left. Now, it's time for Earth return.

Take off during night to be aligned with Earth Plan. then, once in orbit ejection of all landing parachutes that we could have done before take off..

burning to Earth

Periapsis calculation to join orbit at 120 kms. Intercepting Earth Orbit, we should have 230O Dv left which not so much for braking and re-entry

Trying a Radial re-entry at 90 kms to close the orbit

But it's not enough and we have to burn retrograde another 900-1000DV

and perform a lot of  Radial aerobraking passes at 80 kms to reach re-entry orbit here

Re-entry braking was a little bit bumpy as you will see on the short vid following and the end of the post

We got some LF in spare for final approach to base and relight Jet engines and realized that a right winglet was missing...I think it was broken during Mars landing

Approaching the runway

During the vid, you will seevthat we used Vernor engines to keep radial position during re-entry for better braking, but we not enough Oxydyzer left to use them  and that why the re-entry was bumpy.

Then the aircraft was very touchy on pitch axis and even with Atmospheric Autopilot to pilot in FWB I had to use SAS to help...

 

 

In conclusion fo this Mission

RSS cost a lot of DV and there's 3 choices to use Spaceplane to visit our system

-Vertical launches on boosters like Space shuttle but I think it will limit DV capacity

-Stratolaunches associated or not with  ejectable boosters but think I reached the weight and DV limit to 16000-17000DV in orbit DV

-Stratolaunches or vertical launches associated with orbital refueling stations: it could be the best option because you can send bigger but lighter spaceplanes with cargo hold and spacelab using just enough fuel to reach the station .....

Stratolaunch on refueling stations is my preferred option as you can re-used each aircraft....

Edited November 2, 2019 by gilflo