Author Topic: Gateway Minimal Habitation Module  (Read 68083 times)

Offline sdsds

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Re: Gateway Minimal Habitation Module
« Reply #120 on: 11/07/2020 06:13 pm »
"The combined PPE and HALO vehicle is termed the Co-Manifested Vehicle (CMV)." The list of changes this implies for the HALO element (attached) underscores the savings this approach provides.
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Offline Johnnyhinbos

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Re: Gateway Minimal Habitation Module
« Reply #121 on: 11/10/2020 05:13 pm »
OIG’s report, “NASA’S MANAGEMENT OF THE GATEWAY PROGRAM FOR ARTEMIS MISSIONS”

Some tasty tidbits, including this:

https://twitter.com/thesheetztweetz/status/1326220211381563394

https://oig.nasa.gov/docs/IG-21-004.pdf
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline sdsds

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Re: Gateway Minimal Habitation Module
« Reply #122 on: 11/10/2020 05:24 pm »
OIG: "NASA's acceleration of the acquisition for both the PPE and HALO before fully defining the Gateway's requirements added significant costs to the projects' development efforts and increases the risk of future schedule delays and additional cost increases."
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Offline brickmack

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Re: Gateway Minimal Habitation Module
« Reply #123 on: 11/14/2020 05:31 pm »
As the CMV and its components become more fleshed out, this only strengthens my belief that NASA made the wrong selections on both (and that even having separate modules for these purposes was a mistake).

SNCs bid for PPE would've included comparable pressurized volume to HALO, and would still have 2 docking ports (less than 3, but good enough for Orion plus a lander initially). By being more tightly integrated, total system mass was much lower, and it was volumetrically smaller, and it was sized for a round trip from LEO to NRHO back to LEO for cargo delivery, so it could launch on a wider range of rockets (even something as small as Atlas V could carry it). NASA wouldn't have had to deal with two primary contractors, potentially two launches and a docking *or* major design changes to integrate everything on the ground, and ended up with a higher performance module with more options for derivatives.

Considering the likely significant structural changes needed to both parts, I'm starting to wonder if cloning the basic layout of the SNC bid (with the HALO pressure vessel as the primary structure, and then mounting power/propulsion/whatever hardware around it) might be a worthwhile option. That'd eliminate some structural mass, shrink it vertically enough to fit in a short 5m fairing, and probably still retain enough component commonality to still be called "SSL-1300/Cygnus derived"

Offline Zed_Noir

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Re: Gateway Minimal Habitation Module
« Reply #124 on: 11/15/2020 04:02 am »
My take is that Doug Loverro make the change to the initial configuration from 2 separate components to an integrated unit too late in the program development cycle. AIUI changes in the requirements of a program later costs more money and time. Should have kept the initial Gateway configuration once PPE & HALO hardware started to shows up.

Right now NASA is locked into the integrated CMV configuration, basically restarting the Gateway program IMO. It will take even more money and time to go back to the initial Gateway configuration. Never mind the changes that Loverro make probably delay the Gateway by at more than a few months.



Online Robotbeat

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Re: Gateway Minimal Habitation Module
« Reply #125 on: 11/15/2020 02:50 pm »
Hard disagree. Doubtless if you interview both sets of contractors (as OIG would do), they’ll use the combination as an opportunity to excuse why they’re late, but it is a master stroke to accelerate the Gateway and reduce technical risk.
Should’ve been done earlier, but even late in the game it was a good idea.
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Offline yg1968

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Re: Gateway Minimal Habitation Module
« Reply #126 on: 11/15/2020 05:12 pm »
Yes, I agree. The OIG Report has an odd bias against joining both missions but I think that it was right thing to do from a technical perspective. The only reason that it wasn't done from the outset is that FH wasn't initially going to have a taller fairing. If NASA ends up choosing FH for the joint mission, part of the $27M canceling fee that was paid to SpaceX should be recovered, as the report mentions.
« Last Edit: 11/15/2020 05:13 pm by yg1968 »

Offline sdsds

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Re: Gateway Minimal Habitation Module
« Reply #127 on: 11/15/2020 07:04 pm »
Unless someone one day writes a "tell all" account we'll likely never know what motivated much of the decision making. Right now though what's clear is that the CMV approach really does make the HALO side into a "minimal" habitat, with no GNC, propulsion or power generation. Apparently no space to ground communications either, which frankly seems curious.
In any event it's the current path forward, and right now having NASA use FH to launch something big to a cis-lunar location seems like a no-brainer.
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Offline freddo411

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Re: Gateway Minimal Habitation Module
« Reply #128 on: 11/15/2020 09:10 pm »
Unless someone one day writes a "tell all" account we'll likely never know what motivated much of the decision making. Right now though what's clear is that the CMV approach really does make the HALO side into a "minimal" habitat, with no GNC, propulsion or power generation. Apparently no space to ground communications either, which frankly seems curious.
In any event it's the current path forward, and right now having NASA use FH to launch something big to a cis-lunar location seems like a no-brainer.

GNC, propulsion, power and comms are all provided by the physically attached PPE.   They are not missing.

Offline jadebenn

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Re: Gateway Minimal Habitation Module
« Reply #129 on: 11/16/2020 07:34 pm »
Unless someone one day writes a "tell all" account we'll likely never know what motivated much of the decision making. Right now though what's clear is that the CMV approach really does make the HALO side into a "minimal" habitat, with no GNC, propulsion or power generation. Apparently no space to ground communications either, which frankly seems curious.
In any event it's the current path forward, and right now having NASA use FH to launch something big to a cis-lunar location seems like a no-brainer.

GNC, propulsion, power and comms are all provided by the physically attached PPE.   They are not missing.
This. It's simply removing redundant hardware.

Online Robotbeat

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Re: Gateway Minimal Habitation Module
« Reply #130 on: 11/16/2020 09:46 pm »
Yup. Ought to make the overall Gateway cheaper and lighter for the same capability. Means it should be easier to move around to different orbits and require less stationkeeping propellant.

In fact, you might be able to move Gateway into the vicinity of the James Webb Space Telescope. Something like 300-500m/s delta-v I think.
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Lodrig

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Re: Gateway Minimal Habitation Module
« Reply #131 on: 12/15/2020 10:48 pm »
Yup. Ought to make the overall Gateway cheaper and lighter for the same capability. Means it should be easier to move around to different orbits and require less stationkeeping propellant.

In fact, you might be able to move Gateway into the vicinity of the James Webb Space Telescope. Something like 300-500m/s delta-v I think.

I pray that's not for the purposes of fitting corrective optics to the JW like we had to on Hubble.
























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