Author Topic: Deep Space Gateway Power/Propulsion RFI  (Read 16113 times)

Offline titusou

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #60 on: 08/02/2017 03:34 PM »
I revisit the DSG pdf, and realize in the plan drawing, the only module connected with PPE is Hab (using rear port of Hab). Since Hab has 3 ports in total, front/rear/side, that leave 2 ports available to be used, not blocking station keeping thruster.

And then it's Orion/Logistic/Airlock connected to Hab.

So it's interesting to see why PPE need 2nd IDSS port, and if any of them need to support pressured operation, or both just simply used as structure connecting point.


The wild ideal: assuming you have front of PPE as pressured, and have 2 ports next to each other, front and front-side, then you can basically using PPE as mini pressured node to connect more pressured module to move stuff around.

But that for sure complex everything, and make the net weight challenging to meet. After all we have a 7500kg ceiling for "everything"


Titus

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #61 on: 08/02/2017 03:39 PM »
I did a quick render here to show the arrangement in the aft compared with the (more exposed) CAD diagrams of the area from NASA.

What is the source of that CAD picture?

Offline okan170

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #62 on: 08/02/2017 03:56 PM »
I did a quick render here to show the arrangement in the aft compared with the (more exposed) CAD diagrams of the area from NASA.

What is the source of that CAD picture?


"The Ion Propulsion System for the Asteroid Redirect Robotic Mission"  Jul 25, 2016

The Asteroid Redirect Robotic Mission is a Solar Electric Propulsion Technology Demonstration Mission (ARRM) whose main objectives are to develop and demonstrate a high-power solar electric propulsion capability for the Agency and return an asteroidal mass for rendezvous and characterization in a companion human-crewed mission. This high-power solar electric propulsion capability, or an extensible derivative of it, has been identified as a critical part of NASA's future beyond-low-Earth-orbit, human-crewed exploration plans. This presentation presents the conceptual design of the ARRM ion propulsion system, the status of the NASA in-house thruster and power processing development activities, the status of the planned technology maturation for the mission through flight hardware delivery, and the status of the mission formulation and spacecraft acquisition.

https://ntrs.nasa.gov/search.jsp?R=20170002634

PDF is on the page.  This is one of the latest documents I can find of the configuration thats now being used as the DSG Power/Prop Bus in NASA's images.  (I've actually reached out to the authors to see if I can dig up anything more about the module, but haven't heard back yet.)

I revisit the DSG pdf, and realize in the plan drawing, the only module connected with PPE is Hab (using rear port of Hab). Since Hab has 3 ports in total, front/rear/side, that leave 2 ports available to be used, not blocking station keeping thruster.
...

The Habitat module(s) have 4 ports- 2 axial, 2 radial.
« Last Edit: 08/02/2017 05:08 PM by okan170 »

Offline Propylox

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #63 on: 08/05/2017 03:34 PM »
HEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf
Is PPE (and ARM) still unfunded in NASA's 2018 budget, suggesting this RFI and assumptions about a DSG in NRHO are merely castoff program dreams? Is it better to wait until a new, actually viable plan is put forth to speculate on DSG and Lunar operations?
« Last Edit: 08/05/2017 03:36 PM by Propylox »

Offline ncb1397

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #64 on: 08/05/2017 04:27 PM »
HEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf
Is PPE (and ARM) still unfunded in NASA's 2018 budget, suggesting this RFI and assumptions about a DSG in NRHO are merely castoff program dreams? Is it better to wait until a new, actually viable plan is put forth to speculate on DSG and Lunar operations?

Not everything that NASA launches has specific funding. Space technology and Advanced Explorations Systems combined have a billion dollar per year budget with NASA having pretty wide latitude with how it is spent(besides the portion of that budget that Congress directs to specific items). It is how they worked on ARM with Congress against it.

Offline A_M_Swallow

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #65 on: 08/06/2017 12:23 AM »
HEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf
Is PPE (and ARM) still unfunded in NASA's 2018 budget, suggesting this RFI and assumptions about a DSG in NRHO are merely castoff program dreams? Is it better to wait until a new, actually viable plan is put forth to speculate on DSG and Lunar operations?

Not everything that NASA launches has specific funding. Space technology and Advanced Explorations Systems combined have a billion dollar per year budget with NASA having pretty wide latitude with how it is spent(besides the portion of that budget that Congress directs to specific items). It is how they worked on ARM with Congress against it.

Currently DSG development is being paid for using the NextSTEP budget
https://www.nasa.gov/nextstep

The Deep Space Power and Propulsion Element (PPE) has just reached the Request for Information (RFI) i.e. no money yet stage.
https://www.nasa.gov/feature/nasa-power-propulsion-rfi
« Last Edit: 08/06/2017 12:24 AM by A_M_Swallow »

Online Ben the Space Brit

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #66 on: 08/07/2017 10:39 AM »
Purely FWIW, does the 2026 configuration of DSG remind anyone else of Skylab? Maybe they can call it 'Moonlab'? (Yes, I know, I know, my Steven Baxter fanboy is showing again!)
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Online dkovacic

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #67 on: 08/11/2017 10:12 AM »
Could PPE also be used as ISS booster? Since it will have IDSS it can dock. If I calculated it right, it could provide up to 30m/s dV per year over five years without refueling.


Offline Archibald

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #68 on: 08/11/2017 11:38 AM »
Purely FWIW, does the 2026 configuration of DSG remind anyone else of Skylab? Maybe they can call it 'Moonlab'? (Yes, I know, I know, my Steven Baxter fanboy is showing again!)

you nailed it perfectly. Surely, it looks like Skylab silhouette.

Offline AnalogMan

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #69 on: 08/17/2017 10:31 PM »
Draft version of Level 3 & 4 Requirements for the Power and Propulsion Element (PPE) were published yesterday.  Copy attached.

Online oldAtlas_Eguy

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #70 on: 08/18/2017 06:50 PM »
Thanks for the document.

There are a few items that requires mention. This PPE will be the primary communications device for the DSG as long as it is attached to the other DSG elements. It also provides the battery power during solar array eclipses. So the other DSG elements would have very minimal batteries and communications. Unfortunately the weights and other capabilities for orbit maneuvers and RCS are TBD.

There is no mention of a air lock or capability of moving through the two docking ports by personnel. So this document does not require that these ports be anything more than a place holder for other elements that provide for power, communications, and prop transfer but nothing more than a structural attach point. No crew egress. That makes a small problem with the Orion in that it cannot dock at the PPE and still do EVA or crew swap. This makes the supply procedures more complex for the DSG. Requiring the supply VV to dock at a crew access port first to be unloaded then undock and move to the PPE to transfer propellant. This would have to be done unless the other DSG elements all have additional piping and valves to be able to transfer prop through these other elements from the VV to the PPE.

Offline A_M_Swallow

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #71 on: 08/19/2017 09:36 PM »
Thanks for the document.

There are a few items that requires mention. This PPE will be the primary communications device for the DSG as long as it is attached to the other DSG elements. It also provides the battery power during solar array eclipses. So the other DSG elements would have very minimal batteries and communications. Unfortunately the weights and other capabilities for orbit maneuvers and RCS are TBD.

There is no mention of a air lock or capability of moving through the two docking ports by personnel. So this document does not require that these ports be anything more than a place holder for other elements that provide for power, communications, and prop transfer but nothing more than a structural attach point. No crew egress. That makes a small problem with the Orion in that it cannot dock at the PPE and still do EVA or crew swap. This makes the supply procedures more complex for the DSG. Requiring the supply VV to dock at a crew access port first to be unloaded then undock and move to the PPE to transfer propellant. This would have to be done unless the other DSG elements all have additional piping and valves to be able to transfer prop through these other elements from the VV to the PPE.

I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.

Offline tdperk

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #72 on: 08/20/2017 03:25 PM »

...

( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)

I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.

If NASA for some reason wants to continue avoiding necessary technology development, then instead of mastering bulk liquid fuel transfer in weightlessness, a propulsion module which docks to a DSG or other structure to maneuver it and undocks to permit a fresh one to attach should be developed.  That propulsion module should include or be compatible with a return capability for refurbishment.

Online oldAtlas_Eguy

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #73 on: 08/20/2017 09:21 PM »

...

( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)

I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.

If NASA for some reason wants to continue avoiding necessary technology development, then instead of mastering bulk liquid fuel transfer in weightlessness, a propulsion module which docks to a DSG or other structure to maneuver it and undocks to permit a fresh one to attach should be developed.  That propulsion module should include or be compatible with a return capability for refurbishment.
Too complex, and easier to just ship 1-2mt of prop up with a regular commercial re-supply vehicle.

Offline tdperk

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #74 on: 08/21/2017 12:29 AM »

...

( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)

I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.

If NASA for some reason wants to continue avoiding necessary technology development, then instead of mastering bulk liquid fuel transfer in weightlessness, a propulsion module which docks to a DSG or other structure to maneuver it and undocks to permit a fresh one to attach should be developed.  That propulsion module should include or be compatible with a return capability for refurbishment.
Too complex, and easier to just ship 1-2mt of prop up with a regular commercial re-supply vehicle.

After the technology of bulk weightless liquid transfer is established it would be more complex, maybe.

And I have had people tell me the reason SpaceX cannot possibly succeed with the ITS/BFT is that no one knows how to transfer liquids in bulk--so that's a showstopper.  That we cannot count on that task being handled. :P
« Last Edit: 08/21/2017 12:32 AM by tdperk »

Online envy887

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #75 on: 08/22/2017 02:30 PM »
After the technology of bulk weightless liquid transfer is established it would be more complex, maybe.

And I have had people tell me the reason SpaceX cannot possibly succeed with the ITS/BFT is that no one knows how to transfer liquids in bulk--so that's a showstopper.  That we cannot count on that task being handled. :P

The technology is well established. They already do bulk propellant transfer for ISS.

Online oldAtlas_Eguy

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #76 on: 08/22/2017 03:18 PM »
After the technology of bulk weightless liquid transfer is established it would be more complex, maybe.

And I have had people tell me the reason SpaceX cannot possibly succeed with the ITS/BFT is that no one knows how to transfer liquids in bulk--so that's a showstopper.  That we cannot count on that task being handled. :P

The technology is well established. They already do bulk propellant transfer for ISS.
Note: This technology that is well established is for store-able prop and gaseous prop like argon. But that is what the PPE is dealing with. These two prop types do not require the acceleration settling to perform transfers. They are simplistic and is mainly a problem of valves, piping and connect/disconnects at the docking adapter. It is the cryo prop transfer that is not well established.

Online BrightLight

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #77 on: 11/30/2017 03:07 PM »
Update on PP&E work from industry contracts.
From:
https://www.nasa.gov/directorates/heo/nac-heoc
https://www.nasa.gov/sites/default/files/atoms/files/20171130-nac-heoc-ppe_final2.pdf

The 45 day studies are due in January of 2018.

Also shown is an updated DSG from Lockheed Martin with a "newer" version of the PP&E module.
« Last Edit: 11/30/2017 03:21 PM by BrightLight »

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