Author Topic: Deep Space Gateway Power/Propulsion RFI  (Read 8697 times)

Offline A_M_Swallow

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #60 on: 08/02/2017 05:06 AM »

Its the last one you described.  Per the renderings from NASA which match the last version of the ARM bus, the SEP thrusters are mounted on moveable arms around the IDSS port (for ARM, Orion was to dock at this port) but most of the gateway seems to be set up to be on the other end of the bus giving it a more traditional-looking configuration. 

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.  I do not know if the bus is pass-through (basically a tunnel, like Cygnus DS) or if the IDSS ports are just hard points for moving it around using any compatible vehicle- I'm leaning towards just hard points though simply because I cannot find any information about a tunnel in the design. There is some word of a small science airlock at the "front end" of the bus, but thats from much earlier international discussions and not any NASA documents.

I assume the main IDSS port is there to allow the PPE to dock to the rest of the DSG and push the DSG. IMHO The chemical thrusters are to allow manoeuvring during docking plus provide roll control and attitude control to the entire spacestation.

The second IDSS may allow the whole DSG to be manoeuvred but its prime role is likely to be the refuelling point for the ion and chemical thrusters. Such connectors are a coming enhancement to the IDSS. If so there will be pipes to the 3 propellant tanks.

Offline Archibald

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #61 on: 08/02/2017 01:50 PM »
The great thing with electric propulsion is that the DSG could travel on low-energy trajectories, between GEO, L1, L2, different lunar orbits (DRO, LLO) and finally, Sun-Earth libration points.

Delta-V between these various locations are rather small, 1 km/s or less.

What missions for the DSG ?

- GEO: use a space tug to clean Zombie sats like Galaxy 15.
- EML-1 / EML-2: global communications with lunar surface missions.
- DRO / LLO: supports a reusable lunar lander
- SEL-1 / SEL-2: telescope servicing

Offline Jim

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #62 on: 08/02/2017 02:33 PM »
DSG is not going to be used to clean up GEO.

Online titusou

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #63 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

Offline brickmack

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #64 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 #65 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 #66 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 #67 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 #68 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 »

Offline Ben the Space Brit

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #69 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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Offline dkovacic

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #70 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 #71 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.

Online AnalogMan

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Re: Deep Space Gateway Power/Propulsion RFI
« Reply #72 on: Today at 10:31 PM »
Draft version of Level 3 & 4 Requirements for the Power and Propulsion Element (PPE) were published yesterday.  Copy attached.

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