NEXT Lunar Colonisation Program

[Michel Van]

This for Alternate history Story i work on.
and i need advice and help on some details.

NEXT is Lunar Colonisation Program
It reuse the entire Launch rocket and Lunar lander
And orbital refuel for second stage for Lunar Trajectory Injection
To bring 60 metric tons lander to Lunar surface.
The rocket and lander use methalox engine.

The Lander transport 5,7 metric tons to moon and back.
As one way Cargo lander 26 metric tons of equipment.

 

[Michel Van]

This is Next Moonlander concept
I no quite sure if this Design works (help needed)

I use four modified RL-10 (burn Methalox, thrust throttle back)
main issue unsymmetrical thrust on engine out during landing.
other issue the crew cabin lower position the crew has to land on very flat surface.
also balance out subsystem like Life-support, Power system (fuel cell) and others.
Reaction control system fuel is stored in small tanks, also the Lox LH2 tanks for Fuel cells.

Operational time 14 days (fuel cells)
Hibernate mode max 60 day after that too much propellant boil-off
Crew 2 to 4 Exploration phase, then 9 person during Lunar Base phase

For Colonist transport i look option to use Second stage of Next rocket as Lunar lander with bigger cabin.

 

[Michel Van]

I have question about Methalox engines.

I found contradicting data about the ISP.
Like Raptor, Be-4 and others, but those high performance engines.
also about RL-10 on Methalox but that used FLOX 82.5%

Are any data about gas-generator engines with this propellant ?
Is the ISP around 321 sec (3154 m/s2). or lower ?
and about RL-10 on pure Methalox without Fluorine ?

 

[Michel Van]

here the launch rocket in detail.
based to data and calculation from Book Die Grenzenlose Dimension Raumfahrt band 2 by H.O.Ruppe (page 160-176)
all data in Metric

Engine ISP 3106 m/s2 using Methane and Oxygen, thrust 228,227 tons (gas generators cycle)
3803,789 tons lift off Thrust 4564,54 tons by 20 engines
_882,789 tons MECO
_728.618 tons hot stage separation thrust by 3 engines.
_115.615 tons SECO

DV1 = _4536,83 m/s2
DV2 = _5717,785 m/s2
DV3 = 10254,615 m/s2
______-1308,00 m/s2 gravity losses
_______-138,00 m/s2 air resistens
________-20,00 m/s2 losses by various issues
_______8878,61 m/s2 orbit speed (8036 m/s2 needed for 200 km orbit)


Mass brake down first stage

2921000 kg Methalox
__33591 kg unused fuels
__47342 kg fuels tank
__23854 kg structure of all kind
__20000 kg Engines (20) and thrust structure
____200 kg Flight electronic and electric
___7680 kg adapter to second stage
__21513 kg recovery and landing system (parachute airbags)
_154171 kg total empty mass of first stage

Mass brake down second stage

613000 kg Methalox
__9195 kg unused fuels
__9935 kg Fuels tanks
__5006 kg structure of all kind
__8862 kg Engines (3) and thrust structure
__2000 kg Flight electronic and electric
__1950 kg adapter to payload of 65000 kg
_13670 kg recovery and landing system (heat shield parachute airbags)
_50618 kg total empty mass of second stage

_65000 kg Payload

 

[Michel Van]

i look into different launcher for NEXT lander

Payload 65 metric tons in low orbit
Nexus like SSTO, with around 1800 metric ton launch weight
Starship like with Methalox in both stage, around 2065 metric ton launch weight
Middle think with Kerolox first stage and Methalox in second stage, around 2113 metric ton launch weight.
Saturn Analog with Kerolox first stage and Hydrolox in second, around 1904 metric ton launch weight
Reusable version with wings

 

[Michel Van]

For moment i looking into Various launch concepts and orbit modes

on launch rocket it either Nexus like SSTO that bring payload into orbit or two stage rocket, both system reusable.
both have there advantages and disadvantages
SSTO low payload but is easier in reuse, while two stage rocket more efficient, but more komplex in reuse.

Original the second stage had to be refuel in Earth orbit by Tankers, something missing with SSTO.
There alternatives like bringen Fuel tanks into low orbit put together to rocket stage.
or launch empty rocket stage that refuel at fuel depot in orbit.

So many Mods, only one to take...

 

[TheKutKu]

I have question about Methalox engines.

I found contradicting data about the ISP.
Like Raptor, Be-4 and others, but those high performance engines.
also about RL-10 on Methalox but that used FLOX 82.5%

Are any data about gas-generator engines with this propellant ?
Is the ISP around 321 sec (3154 m/s2). or lower ?
and about RL-10 on pure Methalox without Fluorine ?

Some gas generator methalox engines with Sea level nozzle expansion, and then their vacuum version:
-Relativity's Aeon: 310s SL version, presumably in Vacuum, 360s isp Vacuum version
-JiuZhouYunJian's Longyun-70 291.2s SL version, presumably Sea Level. 350s isp Vacuum version
-Landspace's Tianque-12: 284.5s SL version at SL 350s isp vacuum version
-Landspace's Tianque-11: 331s Vacuum version
-Orienspace's YuanLi-85: 278-285s SL version at SL, 325-335s isp in vacuum (Vacuum expansion or not?)
-CASC-AALPT's YF-209: 293s at Sea Level, 329s Vacuum in SL version; ~350s ISP in vacuum verison
-Arianegroup's Prometheus: 320s isp vacuum with sea level version, 340-360s isp vacuum version
-IHI's gas generator methalox engines (LE-8 and others): 312 to 335s isp vacuum with sea level-compatible nozzle expansion, 354s isp vaccum with vacuum nozzle expansion

Generally speaking, for methalox open cycle (so chamber pressure at or under 100 bar), SL isp will be in the 280-300s range, Vac ISP with SL compatible nozzle will be around 310-320s, Vacuum can be easily in the 350-360s range.

 

[Michel Van]

Some gas generator methalox engines with Sea level nozzle expansion, and then their vacuum version:
-Relativity's Aeon: 310s SL version, presumably in Vacuum, 360s isp Vacuum version
-JiuZhouYunJian's Longyun-70 291.2s SL version, presumably Sea Level. 350s isp Vacuum version
-Landspace's Tianque-12: 284.5s SL version at SL 350s isp vacuum version
-Landspace's Tianque-11: 331s Vacuum version
-Orienspace's YuanLi-85: 278-285s SL version at SL, 325-335s isp in vacuum (Vacuum expansion or not?)
-Arianegroup's Prometheus: 320s isp vacuum with sea level version, 340-360s isp vacuum version
-IHI's gas generator methalox engines (LE-8 and others): 312 to 335s isp vacuum with sea level-compatible nozzle expansion, 354s isp vaccum with vacuum nozzle expansion

Generally speaking, for methalox open cycle (so chamber pressure at or under 100 bar), SL isp will be in the 280-300s range, Vac ISP with SL compatible nozzle will be around 310-320s, Vacuum can be easily in the 350-360s range.

Thanks for that Info.
With new data i can refine the Methalox two stage rocket (no way for SSTO with Methalox)

i found data on RL-10 like engine with expander cycle, that burn Methalox
ISP of 346 with P=48 bar, O/F=3,9.
i use this as template for Lander engine based on RL-10

Source:
Basic Analysis of a LOX/Methane expander bleed Engine
by M. Leordi, F. Nasuti, M Onafri
Sapienza university of Rome 2017

 

[TheKutKu]

Thanks for that Info.
With new data i can refine the Methalox two stage rocket (no way for SSTO with Methalox)

i found data on RL-10 like engine with expander cycle, that burn Methalox
ISP of 346 with P=48 bar, O/F=3,9.
i use this as template for Lander engine based on RL-10

Source:
Basic Analysis of a LOX/Methane expander bleed Engine
by M. Leordi, F. Nasuti, M Onafri
Sapienza university of Rome 2017

Full-expander cycle (and not open expander) with methalox can reach about 370s isp in vacuum with practical nozzles, IHI and JAXA have recently tested a compact 30kN engine of such performance, KBKhA have also done similar tests iirc.

source: Research and Development of the Small LOX/Methane Propulsion System for an Experimental Reusable Winged Rocket WIRES#015, 2023
Component tests of a LOX/methane full-expander cycle rocket engine: Single-shaft LOX/methane turbopump, 2019

Other Full-expander engines, such as Avio's M10 and KBKhA's Methane-ran RD-0146 could also reach in the 360s range

 

[Michel Van]

Since i have four RL-10 Methalox engines on Lander.
I thinking to use them already for Trans Lunar Injection from Low orbit,
that would reduce launch mass just to methalox tanks and support system.