Author Topic: A bigger service module for Orion  (Read 11209 times)

Offline pochimax

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Re: A bigger service module for Orion
« Reply #20 on: 06/03/2023 09:10 pm »
Not really the same to be docked (as Apollo Lunar Module) than integrated / connected (as Apollo Service Module to capsule).

No way that kind of "Moonshipstein" idea could do the same work as an ESM+.

Offline whitelancer64

Re: A bigger service module for Orion
« Reply #21 on: 06/07/2023 07:26 pm »
IF someone wants a "bigger" Orion service module. There always the option of docking the current Orion stack to a pre-positioned stripped down SpaceX HLS lander variant with no landing hardware and full tanks in LEO. Plus the bonus of the pressurized volume and pre-positioned cargo that will be available in the lander variant.

Of course getting the Orion to LEO with the SLS will be optional.  ;)

You need to connect that kind of Moonship with Orion with all the requirements... At that point, will be far cheaper to modify the ESM instead of making that "Moonshipstein". Moreover if it is the eurpeans who pay for it as a contribution for Artemis or whatever the name of the NASA cislunar / mars space program in the '30s, '40s, etc.

You do realize that the SpaceX HLS lander is supposed to docked with Orion and act as a mothership, prior to the Gateway platform being available.

IIRC, the length of the Orion ESM is limited by roof ceiling in the VAB. Could make the ESM wider. But that is basically developing a new spacecraft. The European ESM derived from the ATV is the form factor it is because it cost too much change from it's previous form factor.

The Europeans should be considering something else to contributed in the future instead of more Orion ESM to the Artemis program.

The door height of the VAB is 456 ft.

The ML-1 tower when on the crawler transporter is about 400 ft tall. There's plenty of clearance for a taller rocket. The EUS on the Block 1B will increase the height of the SLS by about 30 ft.
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Offline cplchanb

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Re: A bigger service module for Orion
« Reply #22 on: 06/12/2023 06:43 pm »
IF someone wants a "bigger" Orion service module. There always the option of docking the current Orion stack to a pre-positioned stripped down SpaceX HLS lander variant with no landing hardware and full tanks in LEO. Plus the bonus of the pressurized volume and pre-positioned cargo that will be available in the lander variant.

Of course getting the Orion to LEO with the SLS will be optional.  ;)

You need to connect that kind of Moonship with Orion with all the requirements... At that point, will be far cheaper to modify the ESM instead of making that "Moonshipstein". Moreover if it is the eurpeans who pay for it as a contribution for Artemis or whatever the name of the NASA cislunar / mars space program in the '30s, '40s, etc.

You do realize that the SpaceX HLS lander is supposed to docked with Orion and act as a mothership, prior to the Gateway platform being available.

IIRC, the length of the Orion ESM is limited by roof ceiling in the VAB. Could make the ESM wider. But that is basically developing a new spacecraft. The European ESM derived from the ATV is the form factor it is because it cost too much change from it's previous form factor.

The Europeans should be considering something else to contributed in the future instead of more Orion ESM to the Artemis program.

The door height of the VAB is 456 ft.

The ML-1 tower when on the crawler transporter is about 400 ft tall. There's plenty of clearance for a taller rocket. The EUS on the Block 1B will increase the height of the SLS by about 30 ft.

not to mention that the VAB itself was designed to be able to be heightened further when taller rockets are a reality.
i wouldnt worry about height limits at all unless they try to stuff in something taller than a starship on an ML.

Offline Rik ISS-fan

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Re: A bigger service module for Orion
« Reply #23 on: 11/18/2023 07:25 pm »
I was in doubt of starting a new topic or using this one. I decided to do the later.

ESA supplies the Orion ESM (European Service Module), as barter element contribution to ISS and Gateway.
The ESM's for Orion 1 to 6 are under construction. I as European want ESA to be relieved from this contribution (/burden) to the Artemis program. So it can be used to fund a European payload return (human) launch capability.
This would cause a problem for NASA, because Orion doesn't function without ESM.
NASA would be required to fund the development of a new Orion service module; possibly this could go alongside with enlarging it.   

In my opinion launching Orion (humans) on a launcher with giant solid rocket motors is not wise.
It causes very stingent requirements for the launch escape system.
This leads me to the idea to launch Orion from a commercial launch vehicle.
If the launch escape system is integrated into the service module; similar to Boeing Starliner, the reduced mass for the launch escape system can be traded by increasing the size and propulsive capability of the service module. I think MethaLOx would be a good choice for the new service module & launch escape system.

How are you thinking about this?
« Last Edit: 11/18/2023 07:37 pm by Rik ISS-fan »

Offline Hog

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Re: A bigger service module for Orion
« Reply #24 on: 11/18/2023 08:35 pm »
I was in doubt of starting a new topic or using this one. I decided to do the later.

ESA supplies the Orion ESM (European Service Module), as barter element contribution to ISS and Gateway.
The ESM's for Orion 1 to 6 are under construction. I as European want ESA to be relieved from this contribution (/burden) to the Artemis program. So it can be used to fund a European payload return (human) launch capability.
This would cause a problem for NASA, because Orion doesn't function without ESM.
NASA would be required to fund the development of a new Orion service module; possibly this could go alongside with enlarging it.   

In my opinion launching Orion (humans) on a launcher with giant solid rocket motors is not wise.
It causes very stingent requirements for the launch escape system.
This leads me to the idea to launch Orion from a commercial launch vehicle.
If the launch escape system is integrated into the service module; similar to Boeing Starliner, the reduced mass for the launch escape system can be traded by increasing the size and propulsive capability of the service module. I think MethaLOx would be a good choice for the new service module & launch escape system.

How are you thinking about this?
I'm sure there's advantages to swapping boosters, but not because SLS uses solids.  STS supply streams were to be leveraged so the hi-performance hydrogen/oxygen sustainer and large segmented solid booster engines powering a 1 and a half stage orbiter to the edge of orbit.

The 4 segment RSRM is one of the most studied large motors and with reuse you could gauge performance post flight. The 5 segment RSRMV leverages the data from STS but loses the capability to ascertain post flight inspection of the booster as the RSRMVs are expended into the sea.  In order to retain the reusable equipment while supplying 5 segment thrust levels was to require 5.5 segment SRMs similar to the older Constellation proposals with IIRC 6 RS-68s?.
At least in SLS the astros lave a LAS and are at the pointy end of the rocket and not riding aside the propellant tanks and SRBs as in shuttle.

If we get away from SLS/Orion in Artemis and go commercial, it will be total. I don't see Orion on another launcher. just my thoughts.
Paul

Online vp.

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Re: A bigger service module for Orion
« Reply #25 on: 11/19/2023 06:40 am »

ESA supplies the Orion ESM (European Service Module), as barter element contribution to ISS and Gateway.
The ESM's for Orion 1 to 6 are under construction. I as European want ESA to be relieved from this contribution (/burden) to the Artemis program. So it can be used to fund a European payload return (human) launch capability.
This would cause a problem for NASA, because Orion doesn't function without ESM.
NASA would be required to fund the development of a new Orion service module; possibly this could go alongside with enlarging it.   


+1

Online TomH

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Re: A bigger service module for Orion
« Reply #26 on: 11/21/2023 06:20 am »
The original conceptual Orion SM, during CPX, was larger. The original Orion CM diameter was to be a far too large ~6m, and was downsized to a still too massive 5.02m. The original SM was to be the same diameter prior to the ESA taking the contract for it. The ESA builds the current SM on a common bus which they already use for multiple purposes. This is why it has a smaller diameter and also requires jetisonable cover panels. In the Apollo program, the size ratio of SM to CM was > the same ratio between Orion SM and CM. This is because the Apollo SM had to provide the ΔV of the full stack for LOI, and then the ΔV for the CSM for TEI. In the CPX program, the Altair lander would have utilized Hydrolox prop (high iSP, low density, high volumetric tank requirements) for the ΔV of the full stack into LOI, and then the same engine and tanks for landing. The Orion SM in CXP would only have to provide ΔV for the CSM for TEI. As the Orion was carried over to the Artemis Program, its SM still only has to provide ΔV for TEI and no ΔV for LOI. Since Artemis/Orion lunar orbit will be NRHO, LOI requirements are quite different from Apollo. Edit to add:Getting into and out of Apollo's LLO requires much more ΔV than Orion's NRHO.
« Last Edit: 11/21/2023 07:14 am by TomH »

Offline Eric Hedman

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Re: A bigger service module for Orion
« Reply #27 on: 11/21/2023 07:10 am »
The original conceptual Orion SM, during CPX, was larger. The original Orion CM diameter was to be a far too large ~6m, and was downsized to a still too massive 5.02m. The original SM was to be the same diameter prior to the ESA taking the contract for it. The ESA builds the current SM on a common bus which they already use for multiple purposes. This is why it has a smaller diameter and also requires jetisonable cover panels. In the Apollo program, the size ratio of SM to CM was > the same ratio between Orion SM and CM. This is because the Apollo SM had to provide the ΔV of the full stack for LOI, and then the ΔV for the CSM for TEI. In the CPX program, the Altair lander would have utilized Hydrolox prop (high iSP, low density, high volumetric tank requirements) for the ΔV of the full stack into LOI, and then the same engine and tanks for landing. The Orion SM in CXP would only have to provide ΔV for the CSM for TEI. As the Orion was carried over to the Artemis Program, its SM still only has to provide ΔV for TEI and no ΔV for LOI. Since Artemis/Orion lunar orbit will be NRHO, LOI requirements are quite different from Apollo.
If I remember correctly, the NRHO orbit was picked instead of LLO because of the limitations in ΔV of the service module.  Performance limited requirements instead of requirements driving performance.  NASA had created a chart of ΔV requirements to get to different possible place to park Orion and they had little choice but to choose NRHO since it fit what they had in development.

Online TomH

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Re: A bigger service module for Orion
« Reply #28 on: 11/21/2023 07:17 am »
If I remember correctly, the NRHO orbit was picked instead of LLO because of the limitations in ΔV of the service module.  Performance limited requirements instead of requirements driving performance.  NASA had created a chart of ΔV requirements to get to different possible place to park Orion and they had little choice but to choose NRHO since it fit what they had in development.

That is completely correct. I stated this partially in my last sentence above, and have edited to expand that. I was just looking at that chart which is embedded in this article: https://space.stackexchange.com/questions/23992/why-is-a-near-rectilinear-halo-orbit-proposed-for-lop-g-formerly-known-as-deep

Offline woods170

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Re: A bigger service module for Orion
« Reply #29 on: 11/21/2023 08:23 am »
The original conceptual Orion SM, during CPX, was larger. The original Orion CM diameter was to be a far too large ~6m, and was downsized to a still too massive 5.02m. The original SM was to be the same diameter prior to the ESA taking the contract for it.

That is incorrect. The size of the SM had been shrunk to what we see today FIVE years BEFORE ESA got involved. I suggest you educate yourself first in the multiple Design Analysis Cycles (DACs) that Orion went thru under Constellation program (CxP). The Service Module design that was current, when Constellation got canceled in 2010, was the 606/607 design from LockMart.
ESA did not get involved until 2012, which was two years after CxP cancelation. ESA was handed the basics of the 606/607 SM design requirements by NASA, with the order to go from there.

The ESA builds the current SM on a common bus which they already use for multiple purposes.

Once again, this is incorrect. Although the ESM has it roots in the technology developed for the ATV Service Module, they are not the same. There is no such thing as a common bus. The structure for ESM is unique and radically different from that of the ATV SM. The ATV legacy technology used in ESM consists of individual components and heavily redesigned systems. But NOT a common bus.


This is why it has a smaller diameter and also requires jetisonable cover panels.

This is also incorrect. As I explained above, the current size of the ESM is directly derived from the physical dimensions of the original LockMart 606/607 SM designs. The shrinkage of the Orion SM to its current size happened during the Constellation program. It was caused by the severe underperformance of the Ares I design. That required a lot of mass to be shaved from the Orion design. And NASA started doing that by down-sizing the Service Module first. Its length shrunk between the 604 and 605 DACs. And then its diameter shrunk between the 605 and 606 DACs. See the attached image, as well as the attached PDF (from NTRS). The jettisonable panels were a part of the 606/607 design. Which, once again, was the final NASA/Lockheed Martin design of the Orion SM before CxP got axed.

Mass saving efforts drove all those down-sizing design changes and most (if not all) were driven by the upmass limitations of the Ares I launcher design.
« Last Edit: 11/29/2023 10:18 am by woods170 »

Offline Spaceguy5

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Re: A bigger service module for Orion
« Reply #30 on: 11/24/2023 03:25 pm »

If I remember correctly, the NRHO orbit was picked instead of LLO because of the limitations in ΔV of the service module.  Performance limited requirements instead of requirements driving performance.  NASA had created a chart of ΔV requirements to get to different possible place to park Orion and they had little choice but to choose NRHO since it fit what they had in development.

There's a lot more to it than that, though that is a factor. LLO is also incredibly unstable. Just a few days in LLO can turn your spacecraft in a crater, and even if you don't fall out of orbit, it's hard to maintain nav in LLO because of the instability. Especially since the moon doesn't have something like GPS. LLO is just not a good pick if you want to have long duration missions on the moon.

Not to mention LLO has frequent blackout periods of communication with earth and the landed lander or lunar outpost, and frequent shadow (not great if your spacecraft is solar powered and has large power consumption requirements)

NRHO fixes all of that. Almost zero shadow, almost constant communication with earth, a lot more communication coverage with parts of the lunar surface, very stable, etc.

Not to mention having gateway long-term at NRHO gives you a place to stage landers, crew spacecraft, and supplies (with all the advantages and orbit stability listed above). And will demonstrate technologies needed to built a mars transit vehicle for future exploration.


That is completely correct. I stated this partially in my last sentence above, and have edited to expand that. I was just looking at that chart which is embedded in this article: https://space.stackexchange.com/questions/23992/why-is-a-near-rectilinear-halo-orbit-proposed-for-lop-g-formerly-known-as-deep

No it's not completely correct. if you look at that chart, there's a lot more factors than Orion SM DV being traded. A few of which I mentioned above.
« Last Edit: 11/24/2023 04:03 pm by Spaceguy5 »

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