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SLS / Orion / Beyond-LEO HSF - Constellation => Missions To The Moon (HSF) => Topic started by: russianhalo117 on 09/01/2020 05:57 pm

Title: Gateway Discussion Thread
Post by: russianhalo117 on 09/01/2020 05:57 pm
Russia all but withdraws from NASA-led Gateway (Subscription required): http://russianspaceweb.com/protected/imp-2020.html#0831

Summary: US Congress apparently forces NASA's hand regarding ROSCOSMOS involvement in Gateway programme.

Mods if not in the correct place please relocate.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 09/02/2020 12:28 am
It's sad, really.
Title: Re: Gateway Discussion Thread
Post by: lrk on 09/03/2020 10:42 pm
Russia all but withdraws from NASA-led Gateway (Subscription required): http://russianspaceweb.com/protected/imp-2020.html#0831

Summary: US Congress apparently forces NASA's hand regarding ROSCOSMOS involvement in Gateway programme.

Mods if not in the correct place please relocate.

That page asks me to sign in.  Any more details possible? 

If Russia will no longer be providing an airlock, then who will? 
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 09/03/2020 11:21 pm
It's probably based on what Rogozin said in August:

https://www.urdupoint.com/en/technology/russia-not-planning-on-participating-in-us-lu-995656.html
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 09/04/2020 12:52 am
It's probably based on what Rogozin said in August:

https://www.urdupoint.com/en/technology/russia-not-planning-on-participating-in-us-lu-995656.html
Nope based on a May 16th statement that is not from Rogozin and is confirmed via independent sources within the industry. The Russian government has yet to officially withdraw in writing but as a result to the US providing cold hands Russia hasn't attended any meetings or conferences since the conclusion of IAC-3.


Further discussions need to move to the discussions thread as this appears to be an updates only thread.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 09/05/2020 03:59 am
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 09/05/2020 04:36 am
Since there is an Updates only thread and I can't locate the corresponding discussions thread here is the first Artemis Gateway Station Specific Discussion Thread.

Thread Rules:
1) Blatant Politics are off limits as such only brief references may be cited with no further comment and reply.
2) Unwarranted rocket comparisons and mine is better than yours and here why insults are unwelcome as they are off topic.
3) Off topicness is not allowed.
4) All posters should stay classy and polite to one another.
5) further rules may be imposed by mods inline with forums rules.
 
For Updates visit the Gateway Updates Thread: https://forum.nasaspaceflight.com/index.php?topic=51452.0
Title: Re: Gateway Discussion Thread
Post by: klod on 09/05/2020 08:27 am
Russia withdraw from this project by themselves.
Title: Re: Gateway Discussion Thread
Post by: libra on 09/05/2020 11:42 am
Maybe - all the Gateway studies done since June 1999 - damn, 21 years ago ? Some years ago I packed my HD with a load of that stuff.

Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 09/05/2020 04:24 pm
Since there is an Updates only thread and I can't locate the corresponding discussions thread here is the first non-Artemis Gateway Station Specific Discussion Thread.

In the quote above I changed to bold face a portion of the post that might benefit from some clarification. What is a "non-Artemis Gateway?"
typo
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/05/2020 07:06 pm
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 09/05/2020 08:25 pm
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.
Discussion thread this thread is an updates only thread

https://forum.nasaspaceflight.com/index.php?topic=51878.0
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 09/05/2020 09:06 pm
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.

1. Most of the Artemis Accords simply repeats what is contained in other international agreements. Even China agrees with most of the content in the Artemis Accords. Although I don't expect China to be part of the Artemis Accords because of the Wolf amendment and other political reasons.

2. The Gateway is not that important anyways, what is more important is what you build on the Moon and Mars. Russia's commitments must be proportional to its current budget, which is now roughly the same as JAXA's budget.
Title: Re: Gateway Discussion Thread
Post by: su27k on 09/06/2020 04:01 am
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.

1. But Gateway is not governed by Artemis Accords, it's governed by the same inter-governmental agreement as ISS

2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
Title: Re: Gateway Discussion Thread
Post by: jadebenn on 09/06/2020 06:40 am
2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
This. Russia had a privileged position in the ISS coalition because brought a lot to the table. The same can't really be said of Gateway. They don't have unique capabilities, hardware, or experience, and they don't have the financial largess of the US.

Personally, it sounds to me like Russia wanted to be treated as a first-tier partner when they had second-tier capabilities, and got upset when the US called them out on it. I don't think being on the same level as JAXA or the ESA is a bad thing, but perhaps it wounded their pride.
Title: Re: Gateway Discussion Thread
Post by: zubenelgenubi on 09/06/2020 05:57 pm
Moderator: I moved some posts from the update thread to this discussion thread.  Carry on!
Title: Re: Gateway Discussion Thread
Post by: Eric Hedman on 09/06/2020 06:13 pm
2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
This. Russia had a privileged position in the ISS coalition because brought a lot to the table. The same can't really be said of Gateway. They don't have unique capabilities, hardware, or experience, and they don't have the financial largess of the US.

Personally, it sounds to me like Russia wanted to be treated as a first-tier partner when they had second-tier capabilities, and got upset when the US called them out on it. I don't think being on the same level as JAXA or the ESA is a bad thing, but perhaps it wounded their pride.
I think this is the most likely closest to the truth.  It also might be possible they don't have the budget to even build the airlock.  Exiting might be their way of saving face.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/07/2020 12:00 pm
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.

1. But Gateway is not governed by Artemis Accords, it's governed by the same inter-governmental agreement as ISS
Ahem. Even NASA disagrees with you: https://www.nasa.gov/specials/artemis-accords/index.html
Quote from: NASA
International space agencies that join NASA in the Artemis program will do so by executing bilateral Artemis Accords agreements.



2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
Russia being able or not, is not the thing at hand here. Countries are invited by NASA to join Artemis. And Russia being invited to build a mere airlock does not do justice (from the Russian perspective) to Russia's substantial achievements in manned spaceflight.
What particularly irks them is that ESA, which is much less experienced in building stuff for human spaceflight, is building more substantial elements of the Gateway.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/07/2020 12:10 pm
2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
This. Russia had a privileged position in the ISS coalition because brought a lot to the table. The same can't really be said of Gateway. They don't have unique capabilities, hardware, or experience, and they don't have the financial largess of the US.

Personally, it sounds to me like Russia wanted to be treated as a first-tier partner when they had second-tier capabilities, and got upset when the US called them out on it. I don't think being on the same level as JAXA or the ESA is a bad thing, but perhaps it wounded their pride.
I think this is the most likely closest to the truth.  It also might be possible they don't have the budget to even build the airlock.  Exiting might be their way of saving face.

Emphasis mine.

It is not NASA's job to determine whether the Russians have the budget or not. You see, Russia also supposedly didn't have the budget to get Zvezda into orbit, let alone support the early ISS with Progress flights. Yet NASA still asked them to have Zvezda become the cornerstone of the ISS. Don't forget: without Zvezda there is no ISS. It fullfills critical functions that are not present in the US section of the ISS.

But now NASA has relegated one of their most trusted partners in the ISS to a supporting role in Artemis. You bet that Russian pride was hurt when NASA did that. "America First" at its worst. NASA cannot do Artemis on its own and needs international partners to share the cost. Yet NASA won't forget to rub it in that Artemis is first and foremost an American endeavour (despite apparently needing international partners).
Title: Re: Gateway Discussion Thread
Post by: ncb1397 on 09/07/2020 03:44 pm
NASA cannot do Artemis on its own and needs international partners to share the cost.

Sort of. The biggest contribution is the European Service Module, which NASA is actually paying for. The airlock, we don't actually need as the ascent module provides for EVA intrinsically. Then you have the canadarm and I-HAB, which frankly wouldn't be that difficult to get by without and/or replace.

Mainly it comes down to we want to partner with countries so they don't partner with others. This sucks up their limited budgets and helps them fulfill whatever aspirations they might have, so they aren't forced/coaxed into partnerships with some countries we will rather not progress (the same logic applied to buying RD-180 engines from Russia) under potential technology sharing agreements that could apply to their military.

But I wouldn't misjudge that as the inability to go it alone. Russia pulling out doesn't kill Artemis, not even close. What does worry us is Russia replacing the Artemis partnership with a partnership with China. But stopping that partnership may not be within our agency to stop. So be it.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 09/07/2020 07:19 pm
I am not aware of any actions by Congress that prevent cooperation with Russia in respect of Gateway or Artemis. I am not sure what you mean by NASA giving the cold shoulder to Russia.

It is difficult for the U.S. to cooperate with China because of the Wolf amendment but that is a different story.

Emphasis mine. Two things that are considered "a cold shoulder" by the Russians:

1. Contents of the Artemis accords. That is a MAJOR mistake by NASA there. You do NOT prescribe to the Russians how they should act morally.
2. Russia was allowed to build an airlock. I mean: seriously? Just an airlock? Nothing else? That is very much a less than nice way to acknowledge the Russians for their critical contribution to the ISS.

I can very much understand why the Russians are less than enthusiastic about Gateway as it is proposed now.

1. But Gateway is not governed by Artemis Accords, it's governed by the same inter-governmental agreement as ISS
Ahem. Even NASA disagrees with you: https://www.nasa.gov/specials/artemis-accords/index.html
Quote from: NASA
International space agencies that join NASA in the Artemis program will do so by executing bilateral Artemis Accords agreements.

2. If Russia wants to build a battlestar galactica module for Gateway, I don't see why NASA would object, the question is can they do it?
Russia being able or not, is not the thing at hand here. Countries are invited by NASA to join Artemis. And Russia being invited to build a mere airlock does not do justice (from the Russian perspective) to Russia's substantial achievements in manned spaceflight.
What particularly irks them is that ESA, which is much less experienced in building stuff for human spaceflight, is building more substantial elements of the Gateway.

1. No, he is right. Gateway is under the IGA per Mike Gold of NASA:

Quote from: Mike Gold
As many of you may be aware, there’s something called the Intergovernmental Agreement, which is the legal framework that’s been utilized for the International Space Station; it’s worked very, very well.  We hope to leverage it further for the Gateway, which will be an orbital outpost around the Moon.

https://www.state.gov/briefings-foreign-press-centers/artemis-accords-enabling-international-partnerships-for-lunar-exploration/

Quote from: Space News
The Artemis Accords will cover all kinds of activities involved with lunar exploration with the exception of the lunar Gateway, whose international cooperation will be handed through an extension of the existing IGA for the ISS.

https://spacenews.com/nasa-announces-artemis-accords-for-international-cooperation-in-lunar-exploration/


2. What makes you believe that Russia is offended at only being asked to provide the airlock for Gateway?
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/08/2020 07:56 am
NASA cannot do Artemis on its own and needs international partners to share the cost.

Sort of. The biggest contribution is the European Service Module, which NASA is actually paying for.

Sorry, no, NASA is not paying for the Service Module. NASA is only supplying certain SM elements at their own expense. Most notably the service module main engine.

ESA is using and participating in the ISS. To offset their use of USOS elements ESA has barter agreements in place with NASA. For example: for ESA using USOS elements between 2005 and 2015, ESA agreed to fly six (6) ATV supply missions to the ISS, at the full expense of ESA.

But, ESA is also present at the ISS after 2015. So, sometime in 2011/2012 NASA proposed a next barter agreement with ESA. This barter encompasses that ESA develops and builds - at ESA's expense - at least three (3) Orion service modules to offset ESA use of ISS between 2015 and 2024.

An addition to this barter is in advanced stages of negotiation and encompasses ESA building another three (3) Orion service modules - again at the expense of ESA - to offset ESA's use of the ISS until 2028, as well as having an ESA astronaut fly on a future Artemis mission.

Your broad statement that NASA is paying for the ESMs is therefore generally incorrect. Only certain NASA-provided elements of the SMs (main engine and some comms equipment) come at the expense of NASA.
Title: Re: Gateway Discussion Thread
Post by: Proponent on 09/08/2020 01:55 pm
But as a result of the barter, NASA now spends more on ISS logistics than it would without it.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/08/2020 03:01 pm
But as a result of the barter, NASA now spends more on ISS logistics than it would without it.

The assumption being that ESA would have continued to fly ATV if the 2011/2012 barter hadn't come into existence.

But, your assumption is wrong. When the 2005-2015 barter was agreed, ESA immediately told NASA that ESA would build and fly only a limited number of ATV's. Both ESA and NASA already understood back then that after this initial barter a new one would have to be agreed upon, and it would NOT involve ATV's.
As such, back in 2005 NASA already understood that somewhere in the early 2010's there would be a drop in logistics suppy via the international partners. NASA also knew since 2004 that the Shuttle (and its massive up-down capabilities) would go away around 2010. And this situation resulted in Commercial Orbital Transportation Services (COTS) coming into existence in January 2006.

Also, the cost of NASA now having to lift logistics mostly on US vehicles is - at least for ESA contribution - offset in the 2011/2012 barter arrangement involving the Orion Service Module.
Basically NASA did a quick calculation what it would cost to pick up where ATV left off, what part of that was contributable to ESA over the 2015-2021 timeframe, and worked that amount of money into the barter agreement. Which basically is why the 2011/2012 barter arrangement was for three (3) ESMs, instead of the originally targeted two (2). Meaning that ESA paid for one additional ESM to offset their logistics needs via US vehicles.
Title: Re: Gateway Discussion Thread
Post by: libra on 09/08/2020 05:37 pm
Never quite understood why ESA stopped at six ATV when Japan keep launching HTV, including improved variants. Yet japan chunk of ISS is no bigger than ESA...

Title: Re: Gateway Discussion Thread
Post by: pochimax on 09/08/2020 07:30 pm
Never quite understood why ESA stopped at six ATV when Japan keep launching HTV, including improved variants. Yet japan chunk of ISS is no bigger than ESA...
Read the posts inmediate at yours....from woods170
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/08/2020 08:05 pm
Never quite understood why ESA stopped at six ATV when Japan keep launching HTV, including improved variants. Yet japan chunk of ISS is no bigger than ESA...

ATV was for ESA mostly a tech development effort. ESA never intended to switch from tech development to sustained series production. Six ATVs is already one more than ESA intended to fly anyway.
Title: Re: Gateway Discussion Thread
Post by: ncb1397 on 09/08/2020 08:34 pm
NASA cannot do Artemis on its own and needs international partners to share the cost.

Sort of. The biggest contribution is the European Service Module, which NASA is actually paying for.

Sorry, no, NASA is not paying for the Service Module. NASA is only supplying certain SM elements at their own expense. Most notably the service module main engine.

The service module main engine, solar cells, some sensors and avionics, etc. But that wasn't what I was talking about. We have to square your viewpoint with two facts..

1.)ESA/Europe doesn't own the service modules
2.)The service modules weren't free. NASA had to pay hundreds of millions of dollars to multiple companies including in Russia in order to procure them. As such, it isn't a budgetary contribution from ESA towards Artemis (remember, the subject was how NASA is paying for Artemis), it is a budgetary contribution from ESA towards the ISS.

Anyways, regarding Russia, how would Russia get to the gateway? Would they be paying NASA to transport cosmonauts there (similar to how NASA paid for Soyuz seats when they had no other options) until Russia is able to mount their own expeditions with Orel and a domestic super heavy lift rocket? Such thorny issues with regards to how each partner is being treated by the other (financially speaking) is possibly one of the sources of friction in the relationship.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 09/08/2020 11:31 pm
Soyuz could be fitted with an NDS adapter and could dual-launch with a propulsion stage launched on proton or Angara. Would be technologically easy for them. But I’m not sure theylldo it as it’d likely require qual flights for lunar reentry.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 09/09/2020 09:25 am
The biggest contribution is the European Service Module, which NASA is actually paying for.

Sorry, no, NASA is not paying for the Service Module. NASA is only supplying certain SM elements at their own expense. Most notably the service module main engine.

The service module main engine, solar cells, some sensors and avionics, etc.

I already mentioned that the main engine is supplied by NASA. Courtesy of having surplus STS OMS engines laying around. The individual solar cells are supplied by a US company but are paid for by ESA. Part of the avionics comes from US suppliers as well but are again paid for by ESA. Majority of avionics comes from European suppliers and are - again - paid for by ESA.



But that wasn't what I was talking about. We have to square your viewpoint with two facts..

1.)ESA/Europe doesn't own the service modules

Do you even understand what the word "barter" means?
Naturally ESA doesn't own the service modules in the end. ESA hands-over ownership of the ESMs to NASA in exchange for ESA being allowed to use USOS part of ISS, have NASA pay to fly ESA astronauts to and from the ISS, and have ESA astronauts participate in Artemis missions.



2.)The service modules weren't free. NASA had to pay hundreds of millions of dollars to multiple companies including in Russia in order to procure them.

I suggest you come up with evidence to support your statement.



As such, it isn't a budgetary contribution from ESA towards Artemis (remember, the subject was how NASA is paying for Artemis), it is a budgetary contribution from ESA towards the ISS.

It started out as a budgetary contribution from ESA towards ISS. But NASA and ESA agreed to broaden the scope to include Artemis as well. Remember that second set of 3 ESMs I mentioned? That's ESA contribution to Artemis right there. Also: ESPRIT (or whatever the name of the current installment of the design is).
Title: Re: Gateway Discussion Thread
Post by: TrevorMonty on 10/01/2020 02:49 am
NASA are launching the PPE and HALO modules together on same commercial LV. The modules will be bolted together at pad.

http://fiso.spiritastro.net/telecon/Tilley_9-30-20/

No information on what LVs NASA has in mind in this podcast. Maybe Atlas given low orbit.
Mission is assuming sub GTO orbit. PPE has added extra Hall effect thruster ie from 2 to 3x12.5kw units to help with extra mass . Up Xe from 1mt to 3mt, will use 2.5mt for trip to moon, remaining fuel is good for 10-15yrs plus it can be refueled.

Few benefits.
One LV instead of two.
HALO doesn't need service module for trip from TLI to gateway and docking.
Joining units on ground removes docking at lunar orbit and associated risk.




Title: Re: Gateway Discussion Thread
Post by: AstroWare on 10/01/2020 03:44 am
What lunar lander was carried to lunar capture with the PPE during the original launch plan (strikeout on slide 4)? Sorry if it is in the Audio, I have only reviewed the slides right now.

...

Also, it won't matter unless someone protests, but how does this drastic change affect the selected winners of the PPE and HALO?

PPE was competed and winner selected based on multiple criteria, but including price of launch vehicle. Now that NASA is providing the LV, wouldn't that change the calculus?

For example, if NGIS had proposed a PPE launched on now defunct OmegA Heavy, with the PPE/LV being split 400M/150M, and Maxar proposed a 450M/50M split using a negotiated, discounted, Blue origin LV...

Was: NGIS 550M & MAXAR 500M
is: NGIS 400M MAXAR 450M

...

And HALO was sole sourced based on the fact no one else could reasonably accomplish the mission. But without requiring active docking, I would think the technical threshold would be much lower.

A company like Boeing would perhaps have more advantage designing fixed, non mobile space habitats for the ISS then Northrop grumman since the Cygnus abilities are no longer needed.

...

For the sake of the Artemis program, I would hope no one would complain. Just wondering if anyone knows how the Government legally handles these kinds of drastic post-award changes.

Thanks!
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 10/16/2020 08:21 pm
Here is an internal view of the proposed I-Hab from a 2019 report.  The image came from https://liquifer.com/gateway-i-hab/
Note that the diameter of the module is basically the same as the HALO module.

That graphic is heavily out of date since even this subscription section was last updated a month or so ago:
Partners consider major rearrangement in Gateway modules (RSW Annual Subscription required):
PERMALINK: http://russianspaceweb.com/protected/imp-halo-i-hab.html
Title: Re: Gateway Discussion Thread
Post by: GWH on 10/22/2020 02:47 pm
Everybody's going to the Moon (and Mars): The Reg chats to ESA about 10-year plans and sending Tim back to space (https://www.theregister.com/2020/10/20/esa_moon_mars/)

This article could go in many threads. However I put the Parker interview here because it addresses some details of the European contribution to the Gateway, and in particular an aspect I have been wondering about, i.e. how the three elements will be launched.

Feel free to move it if you find location inappropriate.

From the article:
Quote
Parker was reluctant to comment on what would actually launch the ESPRIT modules. While there is potential for a high-performance version of NASA's troubled SLS to be used, he left the selection of the launcher in the hands of the US agency. "I-HAB," he added, "is to be launchable on a commercial launch vehicle."

News like this is perplexing. Launch with SLS and commercial launch make for two very different requirements - namely propulsive capabilities to arrive in NHRO and perform proximity ops at Gateway.
Unless there is a simple tug that can handle this task?
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 10/22/2020 05:31 pm
<snip>
Unless there is a simple tug that can handle this task?

Actually there is a vehicle in development that could fulfilled that tug role with minor modifications.

It is big and white.  ;)
Title: Re: Gateway Discussion Thread
Post by: freddo411 on 10/22/2020 06:58 pm
Everybody's going to the Moon (and Mars): The Reg chats to ESA about 10-year plans and sending Tim back to space (https://www.theregister.com/2020/10/20/esa_moon_mars/)

This article could go in many threads. However I put the Parker interview here because it addresses some details of the European contribution to the Gateway, and in particular an aspect I have been wondering about, i.e. how the three elements will be launched.

Feel free to move it if you find location inappropriate.

From the article:
Quote
Parker was reluctant to comment on what would actually launch the ESPRIT modules. While there is potential for a high-performance version of NASA's troubled SLS to be used, he left the selection of the launcher in the hands of the US agency. "I-HAB," he added, "is to be launchable on a commercial launch vehicle."

News like this is perplexing. Launch with SLS and commercial launch make for two very different requirements - namely propulsive capabilities to arrive in NHRO and perform proximity ops at Gateway.
Unless there is a simple tug that can handle this task?


SLS seems rather unlikely to launch these pieces because every SLS thru 2025 is already assigned to a mission throwing an Orion to the Moon.   I don't think EUS will happen in that timeframe either.

Of course, it's politically required to not cast ANY shade in the direction of SLS.  Even so far as to express the obvious utility of launching on "regular" rockets that cost 1/10 as much as SLS.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 11/10/2020 10:35 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

I finished reading the report. I guess that it explains why NASA decide to take Gateway off the critical path. They must have guessed that the combination of PPE and HALO could create schedule delays.

The Report seems to imply that it was a mistake to combine them. But it's hard to say if it really was a mistake. Integrating both obviously does decrease technical risks but it's hard to stay if it was worth it or not. 

In the report, they say that NASA has yet to decide if Gateway will be used or not for Artemis III. Although verbally, Bridenstine and Loverro were very clear in the spring of 2020 that Gateway is not needed for Artemis III.
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 11/10/2020 11:01 pm
*snip*

In the report, they say that NASA has yet to decide if Gateway will be used or not for Artemis III. Although verbally, Bridenstine and Loverro were very clear in the spring of 2020 that Gateway is not needed for Artemis III.

If the Gateway happens to be in lunar orbit by the time Artemis III launches, there would be little reason to not use it (unless Artemis III doesn't go to NRHO). But no, its use is not required.
Title: Re: Gateway Discussion Thread
Post by: DreamyPickle on 11/11/2020 12:06 am
Without veering into politics: would it be possible to review or cancel the gateway and keep the rest of Artemis, meaning SLS and HLS?

Plans were already made to land without the gateway and it's not clear if any of the HLS participants require it.
Title: Re: Gateway Discussion Thread
Post by: [email protected] on 11/11/2020 12:32 am
Without veering into politics: would it be possible to review or cancel the gateway and keep the rest of Artemis, meaning SLS and HLS?

Plans were already made to land without the gateway and it's not clear if any of the HLS participants require it.
There are already several international partners, so pretty unlikely I guess
Title: Re: Gateway Discussion Thread
Post by: MATTBLAK on 11/11/2020 12:59 am
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface. Perhaps the 'National Team' design with a big enough transfer element would fit the bill?

However; such a beast would have to get out to the Halo orbit in three launches of Commercial rockets. Taking another SLS launch out of the critical path of the mission architecture would be a good thing. 2x launches of Vulcan-Centaur V with 6x solid motors could probably get that Lander out to the Moon. Or 1x Falcon Heavy and 2x Atlas V's.

Also; without a Gateway, it would be difficult to implement a reusable Lander. So perhaps, at least the first two missions would have to use an expendable Lander?
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 11/11/2020 01:44 am
Without veering into politics: would it be possible to review or cancel the gateway and keep the rest of Artemis, meaning SLS and HLS?

Plans were already made to land without the gateway and it's not clear if any of the HLS participants require it.
There are already several international partners, so pretty unlikely I guess

Plus, Gateway was actually initiated (but not funded) by the Obama Administration.
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 11/11/2020 02:58 pm
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface. Perhaps the 'National Team' design with a big enough transfer element would fit the bill?

However; such a beast would have to get out to the Halo orbit in three launches of Commercial rockets. Taking another SLS launch out of the critical path of the mission architecture would be a good thing. 2x launches of Vulcan-Centaur V with 6x solid motors could probably get that Lander out to the Moon. Or 1x Falcon Heavy and 2x Atlas V's.

Also; without a Gateway, it would be difficult to implement a reusable Lander. So perhaps, at least the first two missions would have to use an expendable Lander?

Without the Gateway, also the NRHO would not be required. Lander / Orion could enter a circular lunar orbit (just not a low orbit) at any given inclination, and landing at any point on the lunar surface (rather than just the south pole) would be an option.
Title: Re: Gateway Discussion Thread
Post by: Proponent on 11/11/2020 04:13 pm
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface.

The plan is to build an HLS with the delta-V to go between the halo orbit and the lunar surface, isn't it?  The lander might have a single stage (SpaceX's Starship derivative) or two or three, but it would have the delta-V to take a crew from a halo orbit to the lunar surface and back.
Quote
... without a Gateway, it would be difficult to implement a reusable Lander.

Why?  While parked in a halo orbit, the lander needs to maintain thermal and attitude control and do some station keeping.  Maybe docking it to a gateway helps with that, but it's really not obvious to me that a gateway is terribly valuable.

My understanding of the value of a gateway is that it can mitigate one of the drawbacks of halo-orbit staging, namely the infrequent opportunities for return to Earth.  Unlike LLO staging with adequate delta-V, staging in halo orbit may require a wait of several days before a trans-Earth window opens.  In that case, a gateway station might serve as a backup for keeping a crew alive.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 11/11/2020 05:26 pm
That's not much of an advantage. You are better off building redundant habitats on the Moon. In my view, the main advantage of Gateway is that it is its own destination, just like the ISS is.
Title: Re: Gateway Discussion Thread
Post by: RonM on 11/11/2020 05:54 pm
That's not much of an advantage. You are better building redundant habitats on the Moon. In my view, the main advantage of Gateway is that it is its own destination, just like the ISS is.

And promotes international cooperation just like ISS, making the Artemis program more likely to be funded.
Title: Re: Gateway Discussion Thread
Post by: MATTBLAK on 11/11/2020 10:41 pm
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface.

The plan is to build an HLS with the delta-V to go between the halo orbit and the lunar surface, isn't it?  The lander might have a single stage (SpaceX's Starship derivative) or two or three, but it would have the delta-V to take a crew from a halo orbit to the lunar surface and back.
Quote
... without a Gateway, it would be difficult to implement a reusable Lander.

Why?  While parked in a halo orbit, the lander needs to maintain thermal and attitude control and do some station keeping.  Maybe docking it to a gateway helps with that, but it's really not obvious to me that a gateway is terribly valuable.

My understanding of the value of a gateway is that it can mitigate one of the drawbacks of halo-orbit staging, namely the infrequent opportunities for return to Earth.  Unlike LLO staging with adequate delta-V, staging in halo orbit may require a wait of several days before a trans-Earth window opens.  In that case, a gateway station might serve as a backup for keeping a crew alive.
I'd say it would be difficult, but not impossible to have a Reusable Lander at the Halo orbit without a Propellant Depot - or Gateway - of some sort. Why? Well; the Lander could of course be reusable, but without a Depot or Gateway - a propellant Tanker/s would have to refill that Lander between missions. Either an expendable Tanker or a reusable one (based where?) to fill the Lander. And if a reusable Tanker; who refills that one? And where? I'd say a Depot or Gateway at a certain (floating) location is best, refilled by a series of Commercially procured propellant deliveries. And maybe someday; LOX can be generated In-Situ on the Moon.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 11/13/2020 08:47 pm
Gateway isn’t needed at all for the Moon.

Gateway exists because of Mars. It’s a prototype Mars Transfer Vehicle, and the main reason to stage a lander from Gateway is it’s operational practice for doing the same thing at Mars.
Title: Re: Gateway Discussion Thread
Post by: testguy on 11/13/2020 10:32 pm
Gateway isn’t needed at all for the Moon.

Gateway exists because of Mars. It’s a prototype Mars Transfer Vehicle, and the main reason to stage a lander from Gateway is it’s operational practice for doing the same thing at Mars.
Your reason for Gateway is the first one that makes any sense to me. I don’t remember seeing it in print anywhere.  Have you?  If so please provide source.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 11/13/2020 11:12 pm
I heard it discussed at one of the recent FISO telecoms.
Title: Re: Gateway Discussion Thread
Post by: ncb1397 on 11/14/2020 12:11 am
Gateway isn’t needed at all for the Moon.

Gateway exists because of Mars. It’s a prototype Mars Transfer Vehicle, and the main reason to stage a lander from Gateway is it’s operational practice for doing the same thing at Mars.
Your reason for Gateway is the first one that makes any sense to me. I don’t remember seeing it in print anywhere.  Have you?  If so please provide source.

Here is a slide from a NASA Advisory Council meeting a couple years ago. Note the final bullet point.

Title: Re: Gateway Discussion Thread
Post by: RonM on 11/14/2020 12:49 am
Google deep space transport. It would be tested at Gateway.
Title: Re: Gateway Discussion Thread
Post by: DreamyPickle on 11/14/2020 09:16 pm
Isn't the PPE derived from the asteroid redirect mission? These projects have found ways to change their objective but still remain alive. I have no hope for the "deep space transport" as a method of reaching Mars, it's just a way to spend money on promises 10 years into the future.

It would be much better to focus strictly on the Moon's surface because it is actually reachable with humans and offers far more opportunities for international collaboration and commercial development.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 11/14/2020 09:53 pm
Isn't the PPE derived from the asteroid redirect mission?

Yes, it is.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 11/14/2020 11:26 pm
Isn't the PPE derived from the asteroid redirect mission?

Yes, it is.
...and the PPE on the asteroid redirection mission was justified as a pathfinder for solar electric propulsion for a Mars Transport Vehicle. (Deep Space Transport)


In fact, during hearings, they regularly justified ARRM as testing deep space hardware relevant to Mars, which I thought was a strategic mistake because the actual mission was well worth doing, IMHO, regardless of Mars.
Title: Re: Gateway Discussion Thread
Post by: Joseph Peterson on 02/05/2021 05:52 pm
Question:  Have we seen a Gateway Systems Operations & Maintenance line item estimate yet?

Note:  I'd ask the person who posted the billion per year figure in a different media outlet's comment section directly for a source but he isn't talking to me because politics.  If that isn't a made up figure I definitely have an NSF worthy opinion to post.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 02/06/2021 11:18 am
Google deep space transport. It would be tested at Gateway.

Yes. Lunar Gateway is the former Deep Space Habitat with a new name tag slapped onto it.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/06/2021 01:39 pm
See also this presentation on the Deep Space Gateway and the Deep Space Transport (probably from 2017):
https://nvite.jsc.nasa.gov/presentations/D1_DSG%20perspective_Caram.pdf
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/06/2021 01:45 pm
Question:  Have we seen a Gateway Systems Operations & Maintenance line item estimate yet?

Note:  I'd ask the person who posted the billion per year figure in a different media outlet's comment section directly for a source but he isn't talking to me because politics.  If that isn't a made up figure I definitely have an NSF worthy opinion to post.

See these posts:
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2171510#msg2171510
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2171381#msg2171381
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/06/2021 01:48 pm
Google deep space transport. It would be tested at Gateway.

Yes. Lunar Gateway is the former Deep Space Habitat with a new name tag slapped onto it.

It's changed a lot since then. It's not just the name.

https://en.wikipedia.org/wiki/Deep_Space_Habitat
Title: Re: Gateway Discussion Thread
Post by: Joseph Peterson on 02/07/2021 12:51 am

See these posts:
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2171510#msg2171510
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2171381#msg2171381

Thank you for the response.  I spent some time studying those yesterday.  I was hoping to find a Gateway Systems Operations and Maintenance line item like we get for ISS.  With PPE/Halo expected to launch in 2024 I expect there should be something in 2024 and 2025.  I see the second note in the Gateway section(pp DEXP-64) so I'm willing to believe what I seek is currently hidden here.  Then again maybe I'm way off base and this is more module payments plus logistics costs.

The Logistics Element line item in Table 2 from the OIG report did catch my eye.  $200 million strikes me as a reasonable price SpaceX might charge for a Dragon XL mission.  Is it plausible that the $50.3 million in 2024 is for Dragon XL certification milestone payments and the $204 million in 2025 is the contract amount awarded at the conclusion of the Dragon XL mission currently projected to launch in 2024?
Title: Re: Gateway Discussion Thread
Post by: Lars-J on 02/09/2021 09:27 pm
Quote
SpaceX @SpaceX
NASA has selected Falcon Heavy to launch the first two elements of the lunar Gateway together on one mission! http://nasa.gov/press-release/nasa-awards-contract-to-launch-initial-elements-for-lunar-outpost

NET May 2024
Also discussed here in the SpaceX missions topic: https://forum.nasaspaceflight.com/index.php?topic=53069.0

https://twitter.com/SpaceX/status/1359261256096509953
Title: Re: Gateway Discussion Thread
Post by: tbellman on 02/22/2021 12:29 pm
So; after the co-launch of the first two modules, if the first Habitation module is then attached, does this represent the first, basic usable configuration of the Gateway?

(I'm taking this to the discussion thread.  You posted in the updates thread.)

The first habitation module, HALO, is one of those two initial modules launched together.  And yes, the Lunar Gateway is supposed to be usable with just those two modules.  Not very useful, but enough to have crews transfer between Orion and an HLS lander via the Gateway (instead of docking directly to each other), and have two astronauts staying behind in Gateway for a week or two while the other two astronauts are down on the surface having all the fun.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/22/2021 05:51 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 02/23/2021 01:57 am
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 02/23/2021 05:04 am
Does the plan or record call for a Dragon XL to be docked when the first crew arrives? Perhaps much of the crew activity during their visit would involve outfitting HALO with items delivered aboard Dragon XL.

A big unknown: would an Artemis mission to the lunar surface (that didn't involve the Gateway) have already taken place? If so NASA and its Artemis partners might feel less urgency to prove their lunar capability, and more inclined towards a methodical build-up of resources at the Gateway.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/23/2021 07:42 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.
Title: Re: Gateway Discussion Thread
Post by: ncb1397 on 02/23/2021 07:46 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/23/2021 07:47 pm
Does the plan or record call for a Dragon XL to be docked when the first crew arrives? Perhaps much of the crew activity during their visit would involve outfitting HALO with items delivered aboard Dragon XL.

A big unknown: would an Artemis mission to the lunar surface (that didn't involve the Gateway) have already taken place? If so NASA and its Artemis partners might feel less urgency to prove their lunar capability, and more inclined towards a methodical build-up of resources at the Gateway.

Dragon XL is supposed to be able to stay docked at Gateway for at least a year. But I was under the impression that most consumables on Dragon XL are meant to be transported to the Moon via the Moon landers.

My guess is that under the revised timeline for HLS, Gateway will be ready before the landers.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/23/2021 07:51 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).

What dedicated habitat? HALO is the habitat and it will be the first to arrive at Gateway with the PPE.
Title: Re: Gateway Discussion Thread
Post by: ncb1397 on 02/23/2021 08:02 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).

What dedicated habitat? HALO is the habitat and it will be the first to arrive at Gateway with the PPE.

I'm not sure what the HALO's ECLSS capabilities are (or if it mainly leverages the docked visiting vehicle). But JAXA is providing ECLSS capabilities for the international habitat.

Quote
ESA’s contribution under this memorandum includes building the main habitat for astronauts when they visit the Gateway. Called I-Hab, the module will use environment and life-support systems provided by Japan’s space agency JAXA.
https://www.esa.int/ESA_Multimedia/Images/2020/10/What_is_International_habitat

Exactly what that will look like and what recycling rates are achieved are TBD or not really known publically yet. I did find this abstract from 2014 talking about their efforts in the area and mentioning lunar specifically. I'm guessing it builds on research they have conducted quietly since. IIRC, JAXA wanted to build a seperate habitat for the gateway to test their ECLSS.

Quote
Environmental control and life support systems (ECLSS) provide the basic metabolic needs and environmental conditions necessary to support humans in safe and comfortable environments. As crew-days accumulate, the commodities needing to be supplied to and the wastes that are generated by crewmembers both increase. In order to reduce the mass needing to be resupplied and disposed of, regenerative life support processes can be utilized. Regenerative life support functions that include oxygen recovery from carbon dioxide via the combination of CO2 reduction via a Sabatier process and O2 generative via an electrolysis process. We are planning each elements of air revitalization will be launched on HTV in turn: The water Reclamation element→ The water electrolysis element → The CO2 reduction element→ The CO2 removal element. Air re-vitalization system in JAXA is shown in the paper. Japan should acquire air and water recycling technology. Those technologies are based on environmental technology in which Japan has an advantage. As the Post ISS mission, manned lunar or asteroid exploration is discussed. JAXA has a plan to achieve early in-orbit demonstration of ECLSS technology during the extended ISS operation (2015-2020).
https://ui.adsabs.harvard.edu/abs/2014cosp...40E2852S/abstract

edit: maybe part of it is based on the Kurita water processing module.
Quote
This new system recycles water at a higher level (a water recycling rate of 85% or more) than the water recycling systems currently used on the ISS. It also consumes about one-half of the power and is one-quarter the size and weight of the current systems. Another added benefit of the new system is that it does not require any maintenance. The regeneration of ion exchange resins is self-contained inside the system, and there is no need to replace the resins.
https://www.kurita.co.jp/english/technology/topics/detail01.html
Title: Re: Gateway Discussion Thread
Post by: RonM on 02/23/2021 08:51 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).

HALO will have life support and is the initial habitat module. Half of HALO is taken up by the docking ports, so a dedicated habitat module will be added later.

Quote from: nasa.gov/gateway
The Habitation and Logistics Outpost will be the initial crew cabin for astronauts visiting the Gateway. Its primary purpose is to provide basic life support needs for the visiting astronauts after they arrive in the Orion and prepare for their trip to the lunar surface. It will provide command, control, and data handling capabilities, energy storage and power distribution, thermal control, communications and tracking capabilities, as well as environmental control and life support systems to augment the Orion spacecraft and support crew members. It also will have several docking ports for visiting vehicles and future modules, as well as space for science and stowage.
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 02/23/2021 09:05 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).

What dedicated habitat? HALO is the habitat and it will be the first to arrive at Gateway with the PPE.

There is a dedicated habitat / lab module (commonly called iHab or something similar) being planned by the ESA and Japan, notional launch in 2026. And a larger habitat / lab module by the USA is still possible.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 02/23/2021 09:13 pm
Yes the larger U.S. habitat is now called either the exploration command module or the enhanced habitation capability but it is not yet funded:
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2119245#msg2119245

See also:
https://forum.nasaspaceflight.com/index.php?topic=48676.msg2182320#msg2182320
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/08/2021 04:55 pm
I'm confused about launching from Earth to a Gateway in a lunar NRHO. Does it matter what Earth orbit inclination the vehicle launches into? The target orbit is essentially polar, i.e. out-of-plane compared with the Moon's orbit around the Earth. So is e.g. Vandenberg just as good a launch site as Canaveral?
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 04/08/2021 05:28 pm
Doesn’t matter as much as it would for getting to, say, ISS.
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 04/08/2021 06:06 pm
I'm confused about launching from Earth to a Gateway in a lunar NRHO. Does it matter what Earth orbit inclination the vehicle launches into? The target orbit is essentially polar, i.e. out-of-plane compared with the Moon's orbit around the Earth. So is e.g. Vandenberg just as good a launch site as Canaveral?

The distance to the moon (roughly 30 times Earth's diameter) means that the angular difference of the trajectories of Earth-equatorial launch vs Earth-polar launch is negligible.
Title: Re: Gateway Discussion Thread
Post by: JEF_300 on 04/08/2021 06:17 pm
I'm confused about launching from Earth to a Gateway in a lunar NRHO. Does it matter what Earth orbit inclination the vehicle launches into? The target orbit is essentially polar, i.e. out-of-plane compared with the Moon's orbit around the Earth. So is e.g. Vandenberg just as good a launch site as Canaveral?

It matters, but launching out of the ideal plane is a much more manageable problem on BEO flights than it is for LEO flights.

Let's say you have a spacecraft in an equatorial orbit of Earth, for simplicity, and you want to get into a polar orbit of the Moon. Going from an equatorial to a polar orbit of Earth would require so much delta V it's not even worth considering. But it requires only a (relatively) minor adjustment to your TLI burn to make your spacecraft arrive at the Moon above the Lunar North pole, at which point simply capturing into a Lunar orbit will put you in a polar orbit.

In the same way that launching into the correct inclination is more efficient than getting to orbit and then changing inclination, you can arrive at the Moon already in the right position to get into an orbit that is inclined the way you want it to be. This principle applies to any target point beyond Earth orbit; because the most of the final orbit inclination work can be incorporated as a minor part of an Earth departure or a course adjustment burn, final orbit inclination is usually not a problem for any BEO missions.

So final orbit inclination shouldn't effect your choice of Earth launch sites at all. Also, you can get to the Moon (and Moon adjacent things like L2) from an Earth orbit of any inclination, so long as your TLI burn occurs at the ascending or descending node (Are these the real terms, or Kerbal terms? The principle is the same regardless). Theoretically, it's plenty possible to launch into a polar orbit from Vandenburg, and end up in an equatorial orbit of the Moon, without it even hurting the ∆V budget too much.

But you will hurt the ∆V budget some. Adjusting where around the Moon or L2 you arrive requires additional ∆V. It's a manageable amount, but it isn't nothing. Launching into a polar orbit is inherently less efficient than launching into a due-East orbit. A due-East orbit from the KSC will always be more efficient than a due-East orbit from Wallops. And I've been assuming that you have one TLI burn. It all gets more complicated for the slow transfers.

So I wouldn't expect to see a Vandenberg Lunar launch anytime soon, but there's no reason it can't be done.
Title: Re: Gateway Discussion Thread
Post by: Jim on 04/08/2021 07:53 pm

So I wouldn't expect to see a Vandenberg Lunar launch anytime soon, but there's no reason it can't be done.

See Clementine on Titan II

There was a Mars Lander launched from VAFB.
Title: Re: Gateway Discussion Thread
Post by: Steven Pietrobon on 04/09/2021 09:33 am
Here's a good introduction to the problem. For missions via NRO to the South pole, lighting is less restrictive, being about 12 days every 28 days. In any case, wherever you are launching from, you need your low Earth orbit to intersect the Lunar antipode (plus a few degrees) at the time you arrive at the Moon.

https://www.youtube.com/watch?v=vzdjId224V0
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/09/2021 12:18 pm
That video does a good job of describing the requirements for an Apollo-style lunar surface mission where — immediately upon arrival near the Moon — the spacecraft enters a low lunar orbit that passes over the landing site. That concept of operations imposed lots of launch window constraints.

Many of those constraints go away, or are replaced by others, if the concept of operations has the spacecraft first entering a (very) high lunar orbit when it approaches the Moon.

wherever you are launch from, you need your low Earth orbit to intersect the Lunar antipode (plus a few degrees) at the time you arrive at the Moon.

Yes, this is an excellent point. Has there ever been a "rule of thumb" for the penalty if the launch system misses that goal by a few degrees (or fractions of a degree)? Perhaps a mid-course trajectory correction maneuver performed by the spacecraft could fix it? It does seem like in the worst cases, spacecraft in polar LEO might need to wait half a month for a TLI opportunity. Ouch!

See Clementine on Titan II

It's difficult to extrapolate from Clementine because it was so weird. Quoting Siddiqi's "Beyond Earth:"
Quote
[On] 3 February 1994 [Clementine's] solid-propellant rocket ignited to send the vehicle to the Moon. After two subsequent Earth flybys on 5 and 15 February, on 19 February Clementine successfully entered an elliptical polar orbit (430 × 2,950 kilometers) around the Moon.

What was up with all that??
Title: Re: Gateway Discussion Thread
Post by: spacenut on 04/09/2021 01:34 pm
How many docking connections with the Gateway module have?  Would you have Orion, a lunar lander, and Dragon XL all docked at the same time?
Title: Re: Gateway Discussion Thread
Post by: daedalus1 on 04/09/2021 01:40 pm
How many docking connections with the Gateway module have?  Would you have Orion, a lunar lander, and Dragon XL all docked at the same time?

You would have to have Orion and the lander docked at the same time, and as the XL is long term storage and living space. I would say yes.
Title: Re: Gateway Discussion Thread
Post by: lrk on 04/09/2021 03:39 pm
How many docking connections with the Gateway module have?  Would you have Orion, a lunar lander, and Dragon XL all docked at the same time?

HALO has 3 docking ports, so yes.  ESPIRIT and other future modules will add more, I believe. 
Title: Re: Gateway Discussion Thread
Post by: Prettz on 04/09/2021 06:26 pm
I am guessing that a Dragon XL would also be necessary. The first Dragon XL module is scheduled for 2024 (and the second one for 2026).
Not necessarily necessary.

My understanding is that Orion is limited to 21 days in space because of consumables. How would you bring consumables to Gateway without Dragon XL? It doesn't seem that Orion would have consumables to spare.

Orion doesn't have ISS like air and water recycling capabilities. Gateway likely will (unless we are talking about before the dedicated habitat is flown).

What dedicated habitat? HALO is the habitat and it will be the first to arrive at Gateway with the PPE.

I'm not sure what the HALO's ECLSS capabilities are (or if it mainly leverages the docked visiting vehicle). But JAXA is providing ECLSS capabilities for the international habitat.

Quote
ESA’s contribution under this memorandum includes building the main habitat for astronauts when they visit the Gateway. Called I-Hab, the module will use environment and life-support systems provided by Japan’s space agency JAXA.
https://www.esa.int/ESA_Multimedia/Images/2020/10/What_is_International_habitat

Exactly what that will look like and what recycling rates are achieved are TBD or not really known publically yet. I did find this abstract from 2014 talking about their efforts in the area and mentioning lunar specifically. I'm guessing it builds on research they have conducted quietly since. IIRC, JAXA wanted to build a seperate habitat for the gateway to test their ECLSS.

Quote
Environmental control and life support systems (ECLSS) provide the basic metabolic needs and environmental conditions necessary to support humans in safe and comfortable environments. As crew-days accumulate, the commodities needing to be supplied to and the wastes that are generated by crewmembers both increase. In order to reduce the mass needing to be resupplied and disposed of, regenerative life support processes can be utilized. Regenerative life support functions that include oxygen recovery from carbon dioxide via the combination of CO2 reduction via a Sabatier process and O2 generative via an electrolysis process. We are planning each elements of air revitalization will be launched on HTV in turn: The water Reclamation element→ The water electrolysis element → The CO2 reduction element→ The CO2 removal element. Air re-vitalization system in JAXA is shown in the paper. Japan should acquire air and water recycling technology. Those technologies are based on environmental technology in which Japan has an advantage. As the Post ISS mission, manned lunar or asteroid exploration is discussed. JAXA has a plan to achieve early in-orbit demonstration of ECLSS technology during the extended ISS operation (2015-2020).
https://ui.adsabs.harvard.edu/abs/2014cosp...40E2852S/abstract

edit: maybe part of it is based on the Kurita water processing module.
Quote
This new system recycles water at a higher level (a water recycling rate of 85% or more) than the water recycling systems currently used on the ISS. It also consumes about one-half of the power and is one-quarter the size and weight of the current systems. Another added benefit of the new system is that it does not require any maintenance. The regeneration of ion exchange resins is self-contained inside the system, and there is no need to replace the resins.
https://www.kurita.co.jp/english/technology/topics/detail01.html
Was any of this actually built and tested? I thought ISS was still using the ECLSS that's been up there for more than a decade.
Title: Re: Gateway Discussion Thread
Post by: gemmy0I on 04/09/2021 07:23 pm
Was any of this actually built and tested? I thought ISS was still using the ECLSS that's been up there for more than a decade.
The ISS has had several "experimental" ECLSS racks up there for some time alongside the "main" systems which are part of the station's original design. Some of those experimental racks are considered explicit pathfinders for designs intended for Orion/Gateway.

As I understand it, these experimental ECLSS racks are operated in parallel to the main ones (in an on/off fashion as per needs and experimental goals) to provide additional life support capacity and redundancy beyond the baseline. Since the experimental systems are generally closed-loop (or at least increasingly so), offloading ECLSS responsibility to them should in principle allow more efficient use of consumables than relying solely on the baseline systems.

The extra capacity offered by the profusion of ECLSS currently on the station likely also contributes to the ability to support "oversized" crews for extended periods, like right now where there are 10 crew on station during the week-long Soyuz handover (and there will be 11 during the upcoming Dragon handover). This has been done in the past but presumably now it does not require as much reliance on the consumables of the visiting vehicles as it did e.g. in the Shuttle era.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 04/09/2021 07:40 pm
Scott Pace had an interesting discussion about Gateway at 34 minutes of this video.

He said that Gateway is really there for the sustainability of the lander and for a depot. He said that Mike Griffin didn't think that it wasn't necessary. Pace said that he agreed that it wasn't needed at the beginning but it was needed later on. He added that international partners didn't know if they wanted to go to the Moon but they were interested in Gateway. So Gateway made sense at the beginning because of that. Greg Autry mentionned the fact that Orion was under powered for a Moon mission because of the AJ10. I am convinced that there is a lot of space people that read this forum without being active (we had similar discussions about this topic in this thread).

It's a very interesting video, worth watching in full.

https://youtu.be/nEaVnwB9Um8
Title: Re: Gateway Discussion Thread
Post by: Prettz on 04/09/2021 07:47 pm
Was any of this actually built and tested? I thought ISS was still using the ECLSS that's been up there for more than a decade.
The ISS has had several "experimental" ECLSS racks up there for some time alongside the "main" systems which are part of the station's original design. Some of those experimental racks are considered explicit pathfinders for designs intended for Orion/Gateway.

As I understand it, these experimental ECLSS racks are operated in parallel to the main ones (in an on/off fashion as per needs and experimental goals) to provide additional life support capacity and redundancy beyond the baseline. Since the experimental systems are generally closed-loop (or at least increasingly so), offloading ECLSS responsibility to them should in principle allow more efficient use of consumables than relying solely on the baseline systems.

The extra capacity offered by the profusion of ECLSS currently on the station likely also contributes to the ability to support "oversized" crews for extended periods, like right now where there are 10 crew on station during the week-long Soyuz handover (and there will be 11 during the upcoming Dragon handover). This has been done in the past but presumably now it does not require as much reliance on the consumables of the visiting vehicles as it did e.g. in the Shuttle era.
Is there any place where NASA talks about any of this? I mean recent, after it was already installed. I haven't heard anything of this, and I would've thought NASA would be talking it up every chance they got.
Title: Re: Gateway Discussion Thread
Post by: Proponent on 04/09/2021 07:48 pm
It's difficult to extrapolate from Clementine because it was so weird. Quoting Siddiqi's "Beyond Earth:"
Quote
[On] 3 February 1994 [Clementine's] solid-propellant rocket ignited to send the vehicle to the Moon. After two subsequent Earth flybys on 5 and 15 February, on 19 February Clementine successfully entered an elliptical polar orbit (430 × 2,950 kilometers) around the Moon.

What was up with all that??

You can save a lot of delta-V on the way to lunar orbit if you're wiling to take some time getting there by using a weak-stability-boundary trajectory (you can google it).

Remember LRO/LCROSS?  LRO went to lunar orbit in the usual manner, but LCROSS reached the moon months later following a WSB trajectory that allowed for a nearly vertical impact at the lunar South pole.
Title: Re: Gateway Discussion Thread
Post by: gemmy0I on 04/09/2021 10:48 pm
Was any of this actually built and tested? I thought ISS was still using the ECLSS that's been up there for more than a decade.
The ISS has had several "experimental" ECLSS racks up there for some time alongside the "main" systems which are part of the station's original design. Some of those experimental racks are considered explicit pathfinders for designs intended for Orion/Gateway.

As I understand it, these experimental ECLSS racks are operated in parallel to the main ones (in an on/off fashion as per needs and experimental goals) to provide additional life support capacity and redundancy beyond the baseline. Since the experimental systems are generally closed-loop (or at least increasingly so), offloading ECLSS responsibility to them should in principle allow more efficient use of consumables than relying solely on the baseline systems.

The extra capacity offered by the profusion of ECLSS currently on the station likely also contributes to the ability to support "oversized" crews for extended periods, like right now where there are 10 crew on station during the week-long Soyuz handover (and there will be 11 during the upcoming Dragon handover). This has been done in the past but presumably now it does not require as much reliance on the consumables of the visiting vehicles as it did e.g. in the Shuttle era.
Is there any place where NASA talks about any of this? I mean recent, after it was already installed. I haven't heard anything of this, and I would've thought NASA would be talking it up every chance they got.
I've been wondering the same thing. :) Alas, I've only seen this information dribbled out incidentally in the day-by-day reports, as archived here in NSF's expedition threads (https://forum.nasaspaceflight.com/index.php?topic=50287.0). The daily reports give some background details on these ECLSS experiments when they show up on the crew's logs due to troubleshooting problems or the like.

Off the top of my head, the systems I've seen mentioned recently are the Life Support Rack and Photobioreactor experiments, both of which represent different experimental approaches to closed-loop life support. IIRC, LSR uses solid-state electrolysis to break down CO2 into CO and O2, similar to the MOXIE experiment on the Perseverance rover; and Photobioreactor uses biological methods - algae or something like that - for recovering O2 from CO2.

It would be nice if NASA had a clear summary somewhere describing all the ECLS systems aboard the ISS with their roles, history, and experimental objectives. But they don't usually take the time to post such detailed documentation online for the benefit of us fans. Perhaps such a thing exists in L2 sourced from internal documentation (I don't know).

Personally, I would be quite interested in seeing such a summary as it would allow us to reason about life support capabilities for the purposes of envisioning mission possibilities. It would give better context to the vague tidbits we occasionally hear about consumables status, e.g. "x kg of life support consumables were sent up on freighter X" or "the station has an x-day margin of consumables from current inventory". The real situation is a lot more complicated as there is interplay between the U.S., Russian, and experimental ECLSS racks which are constantly being planned and balanced by mission control. For instance when one of the systems breaks down (which actually happens quite frequently), the official press releases always assure us there is plenty of redundancy but it would be nice to know which systems are relied on in which situations. In extreme situations they can fall back to solid-fuel "oxygen candles" (and presumably some sort of counterpart for emergency CO2 scrubbing), which were infamous for starting fires on Mir and have been used a few times over the years on ISS, but with all the redundancy these days they (thankfully) don't seem to need those very often now.

I agree, it's too bad they don't talk this up more, especially given the connection to future exploration missions. They do talk up the individual experiments in the daily reports' breakdown of the science done each day and sent up on each cargo ship, but it would be nice to know how these systems are performing over the long run. Long-duration, Mars-class exploration missions will need reliable ECLSS that can be maintained without a steady stream of replacement parts and consumables from Earth. With companies like SpaceX aiming for crewed Mars missions within the decade it would be nice to know just how close to reality that actually is (or isn't) from a life-support perspective. (Of course something as big as Starship can afford to brute-force the problem with massive amounts of consumables, but that's getting off-topic for this thread...)
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/10/2021 12:52 pm
It's difficult to extrapolate from Clementine because it was so weird. Quoting Siddiqi's "Beyond Earth:"
Quote
[On] 3 February 1994 [Clementine's] solid-propellant rocket ignited to send the vehicle to the Moon. After two subsequent Earth flybys on 5 and 15 February, on 19 February Clementine successfully entered an elliptical polar orbit (430 × 2,950 kilometers) around the Moon.

What was up with all that??

You can save a lot of delta-V on the way to lunar orbit if you're wiling to take some time getting there by using a weak-stability-boundary trajectory (you can google it).

Indeed, but this wasn't that. The beauty of the WSB trajectories is that the spacecraft gets into lunar orbit without using any propulsion. In contrast, Clementine required 550 m/s of delta-v for lunar insertion.
https://nssdc.gsfc.nasa.gov/planetary/cleminfo.html

Quote
LCROSS reached the moon months later following a WSB trajectory that allowed for a nearly vertical impact at the lunar South pole.

Surface impact certainly reduces the orbit insertion requirement, doesn't it? ;-)

In the case of Clementine the Earth flybys might have been gravity-assist maneuvers. Were they also used to change the plane of the orbit? The mission timeline on the page linked above mentions, "two phasing loop orbits." Is that what these were?

These questions aren't really about Clementine, though, but about future missions to the Gateway. If such missions launched out of Vandenberg would they also require phasing loop orbits?

Title: Re: Gateway Discussion Thread
Post by: Alberto-Girardi on 04/11/2021 10:22 am
Was any of this actually built and tested? I thought ISS was still using the ECLSS that's been up there for more than a decade.
The ISS has had several "experimental" ECLSS racks up there for some time alongside the "main" systems which are part of the station's original design. Some of those experimental racks are considered explicit pathfinders for designs intended for Orion/Gateway.

As I understand it, these experimental ECLSS racks are operated in parallel to the main ones (in an on/off fashion as per needs and experimental goals) to provide additional life support capacity and redundancy beyond the baseline. Since the experimental systems are generally closed-loop (or at least increasingly so), offloading ECLSS responsibility to them should in principle allow more efficient use of consumables than relying solely on the baseline systems.

The extra capacity offered by the profusion of ECLSS currently on the station likely also contributes to the ability to support "oversized" crews for extended periods, like right now where there are 10 crew on station during the week-long Soyuz handover (and there will be 11 during the upcoming Dragon handover). This has been done in the past but presumably now it does not require as much reliance on the consumables of the visiting vehicles as it did e.g. in the Shuttle era.

Do we know any detail of Gateway ECLSS ? Now ISS electrolizes water, producing O2 and H2. O2 is breathed by crew, and then crew releases CO2: The CO2 is collected in a Sbatier reactor, and adding H2 it transforms in CH4 and H2O. CH4 is vented, and water is electrolized, and O2 return in the air. Oxygen is recovered, but every time a bit of H2 is lost, so they need more water. I read that is possible to pirolize the methane, and to recover H2. It will leave a graphite residual, useful for many manufacturing process.  In this way the cycle is completely closed (at least theoretical), and would be optimal for Gateway, because water shipment (for a while it will be from Earth, lunar ice mining will come later) will be very expensive. But a lot of power will be needed.
Title: Re: Gateway Discussion Thread
Post by: Vultur on 04/12/2021 02:10 am
Personally, I would be quite interested in seeing such a summary as it would allow us to reason about life support capabilities for the purposes of envisioning mission possibilities.

Yes, I'd love to see this!

Quote
I agree, it's too bad they don't talk this up more, especially given the connection to future exploration missions.

Yeah.  Some of the cooler stuff done on ISS is not terribly well publicized - IMO they need better PR/media relations.
Title: Re: Gateway Discussion Thread
Post by: Sknowball on 04/12/2021 07:43 pm
Personally, I would be quite interested in seeing such a summary as it would allow us to reason about life support capabilities for the purposes of envisioning mission possibilities.

Yes, I'd love to see this!

Quote
I agree, it's too bad they don't talk this up more, especially given the connection to future exploration missions.

Yeah.  Some of the cooler stuff done on ISS is not terribly well publicized - IMO they need better PR/media relations.

While I don't know if it has everything you are looking for, the International Conference on Environment Systems (https://ttu-ir.tdl.org/handle/2346/58495) is a great resource for papers on current and future ECLSS.   There is a simple overview of NASA Environmental Control and Life Support Technology Development and Maturation for Exploration (https://ttu-ir.tdl.org/bitstream/handle/2346/86395/ICES-2020-200.pdf) as well as a report on the International Space Station as a Testbed for Exploration Environmental Control and Life Support Systems – 2020 Status  (https://ttu-ir.tdl.org/bitstream/handle/2346/86400/ICES-2020-299.pdf).
Title: Re: Gateway Discussion Thread
Post by: gemmy0I on 04/12/2021 11:12 pm
Personally, I would be quite interested in seeing such a summary as it would allow us to reason about life support capabilities for the purposes of envisioning mission possibilities.

Yes, I'd love to see this!

Quote
I agree, it's too bad they don't talk this up more, especially given the connection to future exploration missions.

Yeah.  Some of the cooler stuff done on ISS is not terribly well publicized - IMO they need better PR/media relations.

While I don't know if it has everything you are looking for, the International Conference on Environment Systems (https://ttu-ir.tdl.org/handle/2346/58495) is a great resource for papers on current and future ECLSS.   There is a simple overview of NASA Environmental Control and Life Support Technology Development and Maturation for Exploration (https://ttu-ir.tdl.org/bitstream/handle/2346/86395/ICES-2020-200.pdf) as well as a report on the International Space Station as a Testbed for Exploration Environmental Control and Life Support Systems – 2020 Status  (https://ttu-ir.tdl.org/bitstream/handle/2346/86400/ICES-2020-299.pdf).
Thank you! These papers answered a great many of my questions.

It sounds like a lot of progress has been made, and the ISS is expected to transition to a fully integrated, largely-closed-loop ECLS system within the next few years (as opposed to the hodgepodge of independent component experiments that have been run off-and-on thusfar). At that time the legacy open-loop systems they're replacing will be relegated to emergency spares and packed up in "offline" storage on-station. Until that time, several of the experimental systems will duplicate each other as they're tested head-to-head in anticipation of down-selections to decide which ones will replace the legacy systems in the main life support rack and become the "official" primary life support system for the ISS. Even after those down-selections there will likely be opportunities to retain some of the "losing" designs in their experimental placements to provide supplemental and backup capabilities for the ISS.

Capacity-wise, it seems that most of the experimental ECLSS units are designed to fulfill the needs of a full 4-person USOS crew complement, so there is clearly plenty of excess capacity on tap right now and in the foreseeable future.

One of the papers also made an offhand mention of an existing "European Space Agency Life Support Rack", which would represent even more redundant capacity available on-station. The paper didn't go into more detail on that, so I'm not sure whether that is yet another forward-looking closed-loop experiment or if it's a supplemental open-loop system comparable to the American legacy system.

Interestingly, one of the papers mentioned that Gateway (to bring this back on-topic :) ) will start out with open-loop life support, with the intention of "infusing" these various technologies into the program to transition it to closed-loop over its operational lifespan. I wonder if this is driven more by anticipated technology readiness or by equipment space limitations on Gateway in its early configurations. From what I've read, the initial "minimal Gateway" consisting of just HALO+PPE will be extremely tight on space, so much so that they're looking at putting the toilet in Dragon XL (i.e., making it expendable) because there simply isn't enough room for it in HALO. Having those side docking ports seems to take a big chunk out of HALO's usable rack space compared to the notional extended Cygnus on which it is based.
Title: Re: Gateway Discussion Thread
Post by: Sknowball on 04/13/2021 01:07 am
One of the papers also made an offhand mention of an existing "European Space Agency Life Support Rack", which would represent even more redundant capacity available on-station. The paper didn't go into more detail on that, so I'm not sure whether that is yet another forward-looking closed-loop experiment or if it's a supplemental open-loop system comparable to the American legacy system.

This should have the information you looking for regarding the ESA system. On-orbit Testing of the Advanced Closed Loop System ACLS (https://ttu-ir.tdl.org/bitstream/handle/2346/86479/ICES-2020-510.pdf).

Interestingly, one of the papers mentioned that Gateway (to bring this back on-topic :) ) will start out with open-loop life support, with the intention of "infusing" these various technologies into the program to transition it to closed-loop over its operational lifespan. I wonder if this is driven more by anticipated technology readiness or by equipment space limitations on Gateway in its early configurations. From what I've read, the initial "minimal Gateway" consisting of just HALO+PPE will be extremely tight on space, so much so that they're looking at putting the toilet in Dragon XL (i.e., making it expendable) because there simply isn't enough room for it in HALO. Having those side docking ports seems to take a big chunk out of HALO's usable rack space compared to the notional extended Cygnus on which it is based.

Lockheed Martin did a study under nextSTEP on using Orion to supplement (and in some cases be the prime provider of) some Gateway ECLSS functions during Gateway build up (Integrating Orion and Initial Lunar Gateway Environmental Control and Life Support Systems (https://ttu-ir.tdl.org/bitstream/handle/2346/86404/ICES-2020-432.pdf)).   It is implied in the paper Contingency operations on the Deep Space Gateway:  Approaches, and Considerations to Orbiting Platforms for Deep Space Exploration (https://ttu-ir.tdl.org/bitstream/handle/2346/86406/ICES-2020-485.pdf) that during the "minimal Gateway" phase these ECLSS functions will be provided by Orion.
Title: Re: Gateway Discussion Thread
Post by: kdhilliard on 04/18/2021 12:27 pm
... In the report, they say that NASA has yet to decide if Gateway will be used or not for Artemis III. Although verbally, Bridenstine and Loverro were very clear in the spring of 2020 that Gateway is not needed for Artemis III.

Friday's HLS Announcement Telecon suggested that Gateway is not expected to be used for Artemis III.

39:59 (https://youtube.com/watch?v=y6BqZrs0x4E&t=2399)
Quote from: Lisa Watson-Morgan
For our future missions we will receive from from the Gateway.  For our initial mission we can receive crew from either direct from Orion or from Gateway.

44:43 (https://youtube.com/watch?v=y6BqZrs0x4E&t=2683s)
Quote from: Lisa Watson-Morgan
We will initially be docking with Orion in order to receive the crew.  That is the plan today.  One of the requirements was that for our initial mission, which is the Option A demonstration, everyone had to be able to dock and transfer crew, and for future missions that Mark discussed, some of our sustaining and services missions in the future, we will require docking to both, and we will primarily receive crew from Gateway.  That's our sustained path to give us global access to the Moon and will help us to have a more sustainable program.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 04/18/2021 02:17 pm
I don't think that's a new plan. NASA isn't convinced that Gateway will be ready by 2024. If it's ready, they will use it but they don't expect it to be ready by that time.
Title: Re: Gateway Discussion Thread
Post by: Markstark on 04/18/2021 02:31 pm
IMO, I think selecting Lunar Starship for initial crew landing makes it more likely that Gateway will be used for the first Artemis crew landing. LSS is very ambitious (and awesome) so it’ll take a bit to be ready for crew landings (imo)  and this make it more likely that HALO/PPE will be ready in time.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 04/18/2021 03:04 pm
IMO, I think selecting Lunar Starship for initial crew landing makes it more likely that Gateway will be used for the first Artemis crew landing. LSS is very ambitious (and awesome) so it’ll take a bit to be ready for crew landings (imo)  and this make it more likely that HALO/PPE will be ready in time.

It's possible that SpaceX will be late but Jurczyk said that the milestones in the contract with SpaceX say that the crewed demo Starship will fly in 2024. So, for now, the plan is still to not use Gateway. If SpaceX becomes late in its various milestones under its contract, that could obviously change.
Title: Re: Gateway Discussion Thread
Post by: AU1.52 on 04/18/2021 03:44 pm
IMO, I think selecting Lunar Starship for initial crew landing makes it more likely that Gateway will be used for the first Artemis crew landing. LSS is very ambitious (and awesome) so it’ll take a bit to be ready for crew landings (imo)  and this make it more likely that HALO/PPE will be ready in time.

It's possible that SpaceX will be late but Jurczyk said that the milestones in the contract with SpaceX says that the crewed demo Starship will fly in 2024. So, for now, the plan is still to not use Gateway. If SpaceX becomes late in its various milestones under its contract, that could obviously change.


I was actually thinking the opposite. With LLS being so capable and being able to have so many fail safes it sort of is a Gateway Lite, so no need to rush the actually Gateway. It also has 2 of something the Gateway may not get for a long time - airlocks. 
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 04/18/2021 05:19 pm
IMO, I think selecting Lunar Starship for initial crew landing makes it more likely that Gateway will be used for the first Artemis crew landing. LSS is very ambitious (and awesome) so it’ll take a bit to be ready for crew landings (imo)  and this make it more likely that HALO/PPE will be ready in time.

It's possible that SpaceX will be late but Jurczyk said that the milestones in the contract with SpaceX says that the crewed demo Starship will fly in 2024. So, for now, the plan is still to not use Gateway. If SpaceX becomes late in its various milestones under its contract, that could obviously change.


I was actually thinking the opposite. With LLS being so capable and being able to have so many fail safes it sort of is a Gateway Lite, so no need to rush the actually Gateway. It also has 2 of something the Gateway may not get for a long time - airlocks.

Gateway is fully funded. So at least from a funding perspective, everything is going according to plan.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 04/19/2021 09:10 am
Wonder if the HLS Moonship can docked with the PPE & HALO stack in LEO and boosts them to NRHO as a space tug? Similarly to how the Altair lander do the TLI burn for the whole Constellation Orion stack.
Title: Re: Gateway Discussion Thread
Post by: lrk on 04/19/2021 06:59 pm
Wonder if the HLS Moonship can docked with the PPE & HALO stack in LEO and boosts them to NRHO as a space tug? Similarly to how the Altair lander do the TLI burn for the whole Constellation Orion stack.

Probably would exceed the maximum loads allowed by the NDS specification, so the docking system would probably need a redesign. 

But why?  Falcon Heavy + PPE are sufficient to get the gateway stack into NRHO. 
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/19/2021 10:15 pm
Wonder if the HLS Moonship can docked with the PPE & HALO stack in LEO and boosts them to NRHO as a space tug? Similarly to how the Altair lander do the TLI burn for the whole Constellation Orion stack.

Oh, that's a cruel suggestion.

"Hey buddy, need a lift?"  ;D

Title: Re: Gateway Discussion Thread
Post by: Paul451 on 04/19/2021 10:54 pm
Wonder if the HLS Moonship can docked with the PPE & HALO stack in LEO and boosts them to NRHO as a space tug? Similarly to how the Altair lander do the TLI burn for the whole Constellation Orion stack.
Probably would exceed the maximum loads allowed by the NDS specification, so the docking system would probably need a redesign.

Probably not the docking system itself, but an additional system around it. Like soft-dock systems bring the spacecraft close enough for the hard-dock mechanism to engage, you can use a docking system to hold the spacecraft together in the right orientation for another clamping system to integrate them better.

(OTOH, Apollo CM/LM coped. So maybe not even that is necessary.)
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/20/2021 12:59 am
A trio of comments:
@Zed_Noir: it's now a trivial bit of history but Altair was only going to do the LOI burn, not TLI. TLI was the responsibility of the equally mythical Earth Departure Stage.
@lrk 1: the loads could be quite gentle: the Moonship wouldn't need to use her Raptors for the assist; the landing thrusters would be just fine for the job. The departure burn could last 20 minutes or more.
@lrk 2: the advantage to a chemical TLI is that the solar panels for PPE wouldn't be so grossly degraded by the time they spend in the Van Allen radiation belts. That degradation is reported to by non-trivial and unlike the propellant, a simple resupply mission can't rejuvenate the photovoltaics.

I'll confess I don't have a clear vision of where the various docking ports on the gateway and the Moonship will be located, and which could interact with which. If the Moonship had a docking port on her nose, she could dock to gateway at the location which in all the NASA images is used by Orion. Those long axes of both vehicles "should" be safe for pretty high loads, and the international docking system standard certainly was written with applications like this in mind.

EDIT to add a final thought: it wouldn't have to be the Moonship used for the HLS service that provided the assist to PPE/HALO. Any Starship with the appropriate docking and thruster hardware would do. And if no Starships are available at the time PPE/HALO needs it, they can start off on their own, just according to the current plan. A Starship could catch up anywhere along the way to help out.
Title: Re: Gateway Discussion Thread
Post by: M.E.T. on 04/20/2021 01:36 am
Layman’s question, but could a Starship “be” the Gateway if needed? In other words, is there anything that the current, tiny and expensive Gateway offers from a technical point of view that could not be duplicated by just parking a suitably modified Starship in that orbit instead?
Title: Re: Gateway Discussion Thread
Post by: MATTBLAK on 04/20/2021 01:47 am
Would need to be docked to a multi-docking ported 'Node' but otherwise your potential answer is yes.
Title: Re: Gateway Discussion Thread
Post by: wannamoonbase on 04/20/2021 03:54 am
Layman’s question, but could a Starship “be” the Gateway if needed? In other words, is there anything that the current, tiny and expensive Gateway offers from a technical point of view that could not be duplicated by just parking a suitably modified Starship in that orbit instead?

It would need to be equipped differently for long duration and there would be a lot of dead mass of LOx and LCH4 tanks.  But wouldn't that be a site.

Another Starship tanker in or near NRHO could be helpful over time, that might be interesting as well.  Carry LunOx up from the surface as cargo to help the next Starship go down.

Yeah I'm a junkie for LunOx, is the multiplier that opens the solar system!
Title: Re: Gateway Discussion Thread
Post by: tbellman on 04/20/2021 07:58 am
If you want to use Starship for delivering PPE+HALO (or any other later modules), why not just load it on a normal "chomper" Starship on ground, and have that deliver the modules all the way from ground to the NRHO orbit?  Loads are on the same places as during launch for the entire trip, no docking operations in orbit (just refuelling), et.c.  And if SpaceX's ambitions can be believed, it should be cheaper than launching it on a Falcon Heavy as well.
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 04/20/2021 09:00 am
and unlike the propellant, a simple resupply mission can't rejuvenate the photovoltaics.

But apparently heating them can. (At least for amorphous silicon cells, IIRC.)



Wonder if the HLS Moonship can docked with the PPE & HALO stack in LEO and boosts them to NRHO as a space tug?

To avoid docking, can they fit inside the cargo area?
Title: Re: Gateway Discussion Thread
Post by: Yggdrasill on 04/20/2021 09:21 am
That degradation is reported to by non-trivial and unlike the propellant, a simple resupply mission can't rejuvenate the photovoltaics.
Not exactly rejuvenate, but it would be fairly straight-forward for the lunar Starship to bring along a couple of the ROSA solar panel upgrades for ISS.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/20/2021 03:00 pm
That degradation is reported to by non-trivial and unlike the propellant, a simple resupply mission can't rejuvenate the photovoltaics.
Not exactly rejuvenate, but it would be fairly straight-forward for the lunar Starship to bring along a couple of the ROSA solar panel upgrades for ISS.

True! Hopefully we will start seeing more thinking from NASA about how they can make full use of Starship. In particular, until now there were only vague plans for having EVA capability at the gateway. With Starships visiting though, airlocks out of which to conduct gateway EVAs will be visiting too!

Are there images from SpaceX anywhere showing EVAs from Starship in space, rather than on the surface of a planetary body?
Title: Re: Gateway Discussion Thread
Post by: Jim on 04/21/2021 08:40 pm
If you want to use Starship for delivering PPE+HALO (or any other later modules), why not just load it on a normal "chomper" Starship on ground, and have that deliver the modules all the way from ground to the NRHO orbit?  Loads are on the same places as during launch for the entire trip, no docking operations in orbit (just refuelling), et.c.  And if SpaceX's ambitions can be believed, it should be cheaper than launching it on a Falcon Heavy as well.

Won't be ready.  Also, needs to be launched from KSC.
Title: Re: Gateway Discussion Thread
Post by: tbellman on 04/21/2021 10:35 pm
If you want to use Starship for delivering PPE+HALO (or any other later modules), why not just load it on a normal "chomper" Starship on ground, and have that deliver the modules all the way from ground to the NRHO orbit?  Loads are on the same places as during launch for the entire trip, no docking operations in orbit (just refuelling), et.c.  And if SpaceX's ambitions can be believed, it should be cheaper than launching it on a Falcon Heavy as well.

Won't be ready.  Also, needs to be launched from KSC.

My question was in response to those that were thinking of using the HLS Starship to tug PPE+HALO to NRHO, but I could probably have been clearer about that.  I would assume that the "chomper" version of Starship will be ready earlier than the HLS version.  Although it might not be trusted to launch expensive NASA payloads yet by then (if SpaceX blows up their HLS Starship during launch, it will only cost NASA time, not money or lives).

Good point about needing to be launched from KSC.  I didn't think about that.  But by the time PPE+HALO are ready to be launched, SpaceX might have built their Starship launch pad at KSC.

But my entire comment was mostly being slightly frustrated with people coming up with what seems to me to be complicated solutions.  PPE+HALO is contracted to launch on Falcon Heavy, and I don't expect that to change, nor am I suggesting it should.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 04/22/2021 01:43 am
But my entire comment was mostly being slightly frustrated with people coming up with what seems to me to be complicated solutions.  PPE+HALO is contracted to launch on Falcon Heavy, and I don't expect that to change, nor am I suggesting it should.

Almost everyone participating here is in agreement with you, including Zed_Noir who simply wondered aloud about augmenting that, using Starship as a tug.

The beauty of this would be the low likelihood that attempting it would cause harm. As launched, PPE/HALO would get themselves to the destination in due course of time. If a Starship tug were available, it would allow PPE/HALO to arrive sooner. Sure: there are risks. Collision. Damage from the thrust of the maneuver. Somehow being unable to undock and thus blocking the port. Do you see any of those, or any other risk, as being particularly likely?

We're looking at a future where SpaceX is building and launching lots of Starships as they move fast and break things. Those vehicles are getting to orbit with lots of propellant remaining. How much would SpaceX need to charge NASA to use one of those early vehicles for a tug mission? Maybe not much? Because all SpaceX uses up in the mission is that plentiful propellant.

The mission would pay off two ways: sooner availability of the Gateway in NRHO, and less radiation damage from the Van Allen belts.

What's not to love about this idea?
Title: Re: Gateway Discussion Thread
Post by: pochimax on 07/14/2021 07:12 pm
Sorry for make question in an update only thread...
So, better here, ...has now the PPE part of Gateway 3 AEPS engines?
https://twitter.com/Maxar/status/1414584544301359104
Any idea of the reason?
Title: Re: Gateway Discussion Thread
Post by: Coastal Ron on 08/07/2021 01:48 am
Some of the highlights of the interview with Sean Fuller of NASA:

-Gateway started around 2014, international partners were thinking of what to do next after ISS.
-PPE and HALO launch in November 2024. It takes about 10 months to get to NRHO.
-ihab will be delivered by SLS (co-manifested payload).

I think you mean that the ihab will be LAUNCHED to space by the SLS, but delivered by another vehicle.

Since the ihab module is launch platform agnostic (they were thinking it would launch on Falcon Heavy as recently as last year (https://www.bbc.com/news/science-environment-54537906)), it will need something to send it to the Moon, but it also needs something to dock it to the Gateway.

Not much info on this part that I can find, but we do know the SLS booster falls in the ocean, and the Exploration Upper Stage is just a kicker stage, not a delivery system, so either the ihab docks itself or something else docks the ihab to the Gateway.
Title: Re: Gateway Discussion Thread
Post by: jedijeff123 on 08/07/2021 04:51 am
Some of the highlights of the interview with Sean Fuller of NASA:

-Gateway started around 2014, international partners were thinking of what to do next after ISS.
-PPE and HALO launch in November 2024. It takes about 10 months to get to NRHO.
-ihab will be delivered by SLS (co-manifested payload).

I think you mean that the ihab will be LAUNCHED to space by the SLS, but delivered by another vehicle.

Since the ihab module is launch platform agnostic (they were thinking it would launch on Falcon Heavy as recently as last year (https://www.bbc.com/news/science-environment-54537906)), it will need something to send it to the Moon, but it also needs something to dock it to the Gateway.

Not much info on this part that I can find, but we do know the SLS booster falls in the ocean, and the Exploration Upper Stage is just a kicker stage, not a delivery system, so either the ihab docks itself or something else docks the ihab to the Gateway.
It says it's co-manifested, so I would assume that Orion docks with the module and takes it to Gateway after TLI. 
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 08/07/2021 02:57 pm
Some of the highlights of the interview with Sean Fuller of NASA:

-Gateway started around 2014, international partners were thinking of what to do next after ISS.
-PPE and HALO launch in November 2024. It takes about 10 months to get to NRHO.
-ihab will be delivered by SLS (co-manifested payload).

I think you mean that the ihab will be LAUNCHED to space by the SLS, but delivered by another vehicle.

Since the ihab module is launch platform agnostic (they were thinking it would launch on Falcon Heavy as recently as last year (https://www.bbc.com/news/science-environment-54537906)), it will need something to send it to the Moon, but it also needs something to dock it to the Gateway.

Not much info on this part that I can find, but we do know the SLS booster falls in the ocean, and the Exploration Upper Stage is just a kicker stage, not a delivery system, so either the ihab docks itself or something else docks the ihab to the Gateway.
It says it's co-manifested, so I would assume that Orion docks with the module and takes it to Gateway after TLI.

Yes, see page 97 of this document which states the following:

Quote from: page 97 of NASA's FY22 Budget Congresional Justification
Delivery of I-Hab to the Gateway will be via the SLS Block 1B launch vehicle with Orion providing orbital insertion and docking

https://www.nasa.gov/sites/default/files/atoms/files/fy2022_congressional_justification_nasa_budget_request.pdf

According to the schedule in the ESA-NASA Gateway MOU, this could possibly be on Artemis 4 since delivery of iHab is supposed to be in 2025:

https://forum.nasaspaceflight.com/index.php?topic=51452.msg2160113#msg2160113
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 09/21/2021 05:14 pm
Quote from: NASA Gateway
How does the Gateway compare in size to the @Space_Station? The Gateway is about one-sixth the size of the ISS and can support four crew members for 30 – 60 days while @NASA_Orion spacecraft is docked.

https://twitter.com/NASA_Gateway/status/1440322926461521920
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 10/17/2021 03:54 am
Interesting that NASA is selling Gateway as a technology test bed for Mars. I agree that is the main purpose of Gateway.

https://twitter.com/NASA_Gateway/status/1449544498346930178

Quote from: NASA Gateway
The Moon before Mars! The Gateway, an outpost orbiting the Moon, will be a staging point for human and robotic exploration in deep space that will serve as a technology test bed for Mars.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/17/2021 05:10 am
Interesting that NASA is selling Gateway as a technology test bed for Mars. I agree that is the main purpose of Gateway.

https://twitter.com/NASA_Gateway/status/1449544498346930178

Quote from: NASA Gateway
The Moon before Mars! The Gateway, an outpost orbiting the Moon, will be a staging point for human and robotic exploration in deep space that will serve as a technology test bed for Mars.

Remind me again what Mars-relevant technologies can be tested in lunar NRHO but not in LEO? Or HEO, for that matter, if you want to have greater exposure to interplanetary radiation environments.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 10/19/2021 02:26 am
Interesting that NASA is selling Gateway as a technology test bed for Mars. I agree that is the main purpose of Gateway.

https://twitter.com/NASA_Gateway/status/1449544498346930178

Quote from: NASA Gateway
The Moon before Mars! The Gateway, an outpost orbiting the Moon, will be a staging point for human and robotic exploration in deep space that will serve as a technology test bed for Mars.

Remind me again what Mars-relevant technologies can be tested in lunar NRHO but not in LEO? Or HEO, for that matter, if you want to have greater exposure to interplanetary radiation environments.

The idea of Gateway came from the Journey to Mars program and its Deep Space Habitat (and the related Mars Transit Vehicle). I don't see why a Gateway would be needed for the Moon. However, it is true that Gateway is located in NRHO in order to be used as a staging point for Orion for lunar missions.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/19/2021 03:09 am
The idea of Gateway came from the Journey to Mars program and its Deep Space Habitat (and the related Mars Transit Vehicle). I don't see why a Gateway would be needed for the Moon. However, it is true that Gateway is located in NRHO in order to be used as a staging point for Orion for lunar missions.

The idea that a vehicle with 14% the pressurized volume of the ISS (and that's including Gateway's I-HAB module!) would be viable as a Mars Transit Vehicle seems farcical to me. Frankly, the only semi-plausible justification I've heard is to address certain edge-case logistical and emergency concerns surrounding Artemis lunar operations. Which would seem to support keeping the Gateway as small as possible to fulfill those needs, recognizing that by the time Gateway could grow further, the rest of the Artemis program (*cough* Starship *cough*) will grow beyond needing Gateway at all.
Title: Re: Gateway Discussion Thread
Post by: BrianNH on 10/19/2021 12:05 pm
The intention is not to turn the Gateway into a Mars Transfer Vehicle, but to assemble a Mars Transfer Vehicle at the Gateway.  The Gateway has many purposes, one of which is to provide a long term habitation environment in the harsher radiation environment away from Earth.
Title: Re: Gateway Discussion Thread
Post by: eeergo on 10/19/2021 01:18 pm
Interesting that NASA is selling Gateway as a technology test bed for Mars. I agree that is the main purpose of Gateway.

https://twitter.com/NASA_Gateway/status/1449544498346930178 (https://twitter.com/NASA_Gateway/status/1449544498346930178)

Quote from: NASA Gateway
The Moon before Mars! The Gateway, an outpost orbiting the Moon, will be a staging point for human and robotic exploration in deep space that will serve as a technology test bed for Mars.

Remind me again what Mars-relevant technologies can be tested in lunar NRHO but not in LEO? Or HEO, for that matter, if you want to have greater exposure to interplanetary radiation environments.

Thermal.
Comms.
GNC.
Logistics.
Radiation (HEO is not representative in general, and once you're out in the boonies you might as well orbit something interesting).
Staging point for surface ops + safe haven.

You 'can' test autonomatization and related topics on ISS, LEO, or even down on Earth. But until you try it in representative conditions, well, you haven't tried it.

Plus, you know, the whole Artemis "detail".
Title: Re: Gateway Discussion Thread
Post by: Khadgars on 10/19/2021 02:18 pm
Some of the highlights of the interview with Sean Fuller of NASA:

-Gateway started around 2014, international partners were thinking of what to do next after ISS.
-PPE and HALO launch in November 2024. It takes about 10 months to get to NRHO.
-ihab will be delivered by SLS (co-manifested payload).

I think you mean that the ihab will be LAUNCHED to space by the SLS, but delivered by another vehicle.


That's like saying Falcon 9 only launches crew above the Karman line and they are delivered to the ISS by another vehicle, which is equally ridiculous distinction.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/19/2021 03:06 pm
The intention is not to turn the Gateway into a Mars Transfer Vehicle, but to assemble a Mars Transfer Vehicle at the Gateway.  The Gateway has many purposes, one of which is to provide a long term habitation environment in the harsher radiation environment away from Earth.

Unless you're refueling the Mars Transfer Vehicle with hydrogen fuel you mined on the Moon, there's no reason to assemble it in NRHO. it's much more efficient to assemble in LEO.

Testing life in a harsher radiation environment is the only part that's unique about NRHO. I suppose even HEO is within Earth's magnetosphere, so that wouldn't be sufficient to test the true interplanetary environment. But I'm not convinced you need a particularly large station to test the basics of "what shielding can protect against cosmic rays." And for long-term studies you'd want an uncrewed station anyway (just sticking radiation sensors inside whatever shielding you're testing): it feels bad to have astronauts perform a mission that's solely "we're going to irradiate you with unknown energies for months just to see what interesting cancers you get." At least for an actual Mars mission, you get to visit Mars, in addition to getting new and exciting cancers.

Thermal.
Comms.
GNC.
Logistics.
Radiation (HEO is not representative in general, and once you're out in the boonies you might as well orbit something interesting).
Staging point for surface ops + safe haven.

You 'can' test autonomatization and related topics on ISS, LEO, or even down on Earth. But until you try it in representative conditions, well, you haven't tried it.

Plus, you know, the whole Artemis "detail".

Other than the radiation environment, what parts of those can't be tested in LEO and/or with an uncrewed station? (Or wouldn't be representative in NRHO either, not sure why GNC or logistics in that orbit would be meaningful compared to a Mars mission.) And as mentioned above, if the main purpose of Gateway is "so we can irradiate astronauts to see what happens," at some point you'd rather just go to Mars and take the chance.

And I did concede a minimal station for parking an HLS Starship when not in use (assuming that the Power and Propulsion Element (PPE) provides more power and propulsion than Starship has itself...) and for certain safe-haven scenarios (e.g., sticking the crew on Gateway while a couple of Starships do refueling operations to allow the crew to fly back to Earth orbit on a Earth-Moon Cycler Starship) could be useful. But the PPE + Habitation and Logistics Outpost (HALO) are probably sufficient for those needs, and it wouldn't need to be kitted out beyond that (other than throwing in some radiation monitors to see what HALO is like long-term).
Title: Re: Gateway Discussion Thread
Post by: BrianNH on 10/19/2021 03:31 pm
Bump.  Just realized that there is a Gateway discussion thread and we have been polluting the update thread with discussions.
Title: Re: Gateway Discussion Thread
Post by: eeergo on 10/19/2021 03:34 pm

Thermal.
Comms.
GNC.
Logistics.
Radiation (HEO is not representative in general, and once you're out in the boonies you might as well orbit something interesting).
Staging point for surface ops + safe haven.

You 'can' test autonomatization and related topics on ISS, LEO, or even down on Earth. But until you try it in representative conditions, well, you haven't tried it.

Plus, you know, the whole Artemis "detail".

Other than the radiation environment, what parts of those can't be tested in LEO and/or with an uncrewed station? (Or wouldn't be representative in NRHO either, not sure why GNC or logistics in that orbit would be meaningful compared to a Mars mission.) And as mentioned above, if the main purpose of Gateway is "so we can irradiate astronauts to see what happens," at some point you'd rather just go to Mars and take the chance.

And I did concede a minimal station for parking an HLS Starship when not in use (assuming that the Power and Propulsion Element (PPE) provides more power and propulsion than Starship has itself...) and for certain safe-haven scenarios (e.g., sticking the crew on Gateway while a couple of Starships do refueling operations to allow the crew to fly back to Earth orbit on a Earth-Moon Cycler Starship) could be useful. But the PPE + Habitation and Logistics Outpost (HALO) are probably sufficient for those needs, and it wouldn't need to be kitted out beyond that (other than throwing in some radiation monitors to see what HALO is like long-term).


Again:


Thermal.Comms.GNC.Logistics.Radiation.Staging point for surface ops + safe haven.
Aspects of automation and resiliency.
Neither of these can be simulated with a relevant amount of fidelity in Earth orbit, and have much more to do with Martian conditions when tested in cislunar than in Earth orbit.
That *you* are willing to "take the chance" doesn't mean there aren't thousands of professionals who, as their name suggest, are not so cavalier with unnecessarily sending those with the right stuff towards avoidable death or maiming, or that it's the right way forward.
When you're graciously 'conceding' graces to the NRHO (not HALO) station concept just as a garage for a magical does-it-all SS says a lot though.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/19/2021 03:41 pm
Bump.  Just realized that there is a Gateway discussion thread and we have been polluting the update thread with discussions.

Agreed, I'd be happy to have the mods move over the more recent comments from that thread into this one.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/19/2021 04:15 pm
Again:


Thermal.Comms.GNC.Logistics.Radiation.Staging point for surface ops + safe haven.
Aspects of automation and resiliency.
Neither of these can be simulated with a relevant amount of fidelity in Earth orbit, and have much more to do with Martian conditions when tested in cislunar than in Earth orbit.
That *you* are willing to "take the chance" doesn't mean there aren't thousands of professionals who, as their name suggest, are not so cavalier with unnecessarily sending those with the right stuff towards avoidable death or maiming, or that it's the right way forward.
When you're graciously 'conceding' graces to the NRHO (not HALO) station concept just as a garage for a magical does-it-all SS says a lot though.

Let me walk through these one at a time, then:

Thermal: Do you need a crewed station to understand the thermal environment of deep space? What do you learn from a crewed station vs. from a PPE+HALO station that sits in NRHO uncrewed? If you're feeling really fancy, stick some radiators inside that produce human-level amounts of heat (plugged into the solar panels) to increase fidelity, but if the goal is understanding how you radiate when you don't have a bright Earth next to you, you don't need crew onboard to do that.

Comms: You can send messages back and forth to the PPE+HALO without crew being there: software to relay communications is pretty readily available. Plus, communication with NRHO may be somewhat different from Mars comms due to the difference in distance. And we've already sent comms back and forth with deep-space missions before: what does having a human in the loop add?

GNC: How does knowing how to maintain a NRHO orbit help understand Trans-Mars Injections (TMI)? They're completely unrelated orbits, in fact NASA has done TMI multiple times but is sufficiently uncertain about NRHO that they want to send the CAPSTONE mission to study it. I do not understand how a Gateway station in NRHO, crewed or uncrewed, helps with GNC for a Mars mission.

Logistics: Again, how does "we understand the logistics of supplying a NRHO station" help with a Mars mission? As a quick example, Dragon XL is a logistics module intended to help resupply Gateway. Do you think anything of Dragon XL (other than comms, maybe, and see above note regarding comms) is relevant to supplying a Mars mission? Being able to access the Gateway once every two weeks vs. being able to access Mars once every two or so years is sufficiently different that nothing learned from the Gateway will help for Mars.

Staging: Do you mean "staging for Artemis missions" (where the PPE+HALO probably are moderately useful, but no more than that), or "staging for Mars"? Because as mentioned a few comments back, it makes absolutely no sense to stage Mars missions out of lunar orbit unless you have a sufficient lunar economy that a significant portion of your Mars mission's mass will originate from the Moon. Which isn't happening any time soon.

Autonomatization: So basically "unless we isolate people where they really will die if the mission fails, we don't know how they'll handle isolated scenarios like a Mars mission"? There's certainly a psychological aspect to knowing that your life really is on the line, but it feels a little unethical: if you phrased it as "we're running the mission on Earth, but there's a bomb that will kill the participants if the mission fails," no one would approve. In any event, a Gateway station in NRHO doesn't fully simulate this anyway: you could potentially be resupplied in a matter of months, perhaps weeks if specific plans were made in advance to launch a backup mission, as opposed to having to work the rest of the mission with only what you currently have. And if you're concerned about failure states which lead to immediate death, LEO has plenty of those.

Radiation: I left this one for last because it's honestly the best argument for long-term habitation in NRHO: whatever shielding we develop won't be perfect, and uncrewed experiments telling us exactly what radiation exists there can't tell us how that radiation environment affects humans. And here the shorter mission duration works for the Gateway: having a person experience this environment for six months, then return to Earth for full medical checks, might tell us things that would be useful for Mars (e.g., if that six-month test tells us that a full year would lead to cognitive degradation that impacts mission performance, that's an important piece of information). That said, "Gateway exists so we can irradiate astronauts and see what their health will be like during a journey to Mars" seems like a hard sell to the public, and a Mars mission will necessarily have a lot of unknowns that can't be tested before it actually happens: perhaps crew health is one of them.
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 10/19/2021 05:06 pm
Again:
Thermal.Comms.GNC.Logistics.Radiation.
Staging point for surface ops + safe haven.
Aspects of automation and resiliency.
Neither of these can be simulated with a relevant amount of fidelity in Earth orbit, and have much more to do with Martian conditions when tested in cislunar than in Earth orbit.[...]
Let me walk through these one at a time, then:
Thermal: Do you need a crewed station to understand the thermal environment of deep space? What do you learn from a crewed station vs. from a PPE+HALO station that sits in NRHO uncrewed? [...]
Comms: You can send messages back and forth to the PPE+HALO without crew being there: [...]
[...]

[Edit: Trimmed now that the originals have been moved over.]

Researching and developing things costs money. This list would cost serious money. That money isn't available unless you get a lot of buy-in from across the agency and, to reduce the risk of cancellation, international partners. HSF gets more funding for development associated with actual crew flights than for tech-development without crew flights. If you want the above things done, you will not get adequate funding (or potentially, any funding) unless it's a significant part of the HSF program of record.

It sucks. It's not efficient. But it's just the reality of how Congress, WH, Agency and it's Centres interact.
Title: Re: Gateway Discussion Thread
Post by: Proponent on 10/19/2021 07:05 pm
Radiation: I left this one for last because it's honestly the best argument for long-term habitation in NRHO: whatever shielding we develop won't be perfect, and uncrewed experiments telling us exactly what radiation exists there can't tell us how that radiation environment affects humans. And here the shorter mission duration works for the Gateway: having a person experience this environment for six months....

Has NASA ever suggested crewing the gateway for more than a few weeks per year?
Title: Re: Gateway Discussion Thread
Post by: ThereIWas3 on 10/19/2021 08:50 pm
Another thing about comms testing.  The Moon is not changing its distance from Earth very much.  The Gateway, being in orbit will likewise not have very great velocity with respect to Earth.   Mars on the other hand is moving quite quickly closer and further away, at hugely greater distances, depending where the planets are in their respective orbits.  A vehicle in transit to Mars will also be moving away quite quickly.

The varying Doppler shifts, propagation times, and beam-spreading issues are not unknown territory however.  This is undergraduate EE stuff.  NASA has been doing this kind of thing since the first Mars landers.  The physics of electromagnetic radiation is very well understood.  So  are the radiation effects on deep-space electronics.

I do not see anything involving radio communication that needs to be tested near the Moon before it can be used on Mars missions.
Title: Re: Gateway Discussion Thread
Post by: trimeta on 10/19/2021 08:57 pm
Radiation: I left this one for last because it's honestly the best argument for long-term habitation in NRHO: whatever shielding we develop won't be perfect, and uncrewed experiments telling us exactly what radiation exists there can't tell us how that radiation environment affects humans. And here the shorter mission duration works for the Gateway: having a person experience this environment for six months....

Has NASA ever suggested crewing the gateway for more than a few weeks per year?

If that's the max crewed stay in NRHO, then I'm not sure how much data Gateway will give on long-term exposure to interplanetary radiation, which is the one thing it's good for that can't be done in LEO or via an uncrewed mission in NRHO. If you're just getting a few weeks of data, might as well just prep a Starship for an Apollo 8-style mission (not dearMoon, that's free return not lunar orbit) and hang out around the Moon for around that duration to soak up the rays.
Title: Re: Gateway Discussion Thread
Post by: gemmy0I on 10/19/2021 10:44 pm
Researching and developing things costs money. This list would cost serious money. That money isn't available unless you get a lot of buy-in from across the agency and, to reduce the risk of cancellation, international partners. HSF gets more funding for development associated with actual crew flights than for tech-development without crew flights. If you want the above things done, you will not get adequate funding (or potentially, any funding) unless it's a significant part of the HSF program of record.

It sucks. It's not efficient. But it's just the reality of how Congress, WH, Agency and it's Centres interact.
☝ This. The official "scientific and engineering reasons" for building Gateway in NRHO may be "nice to have" from the perspectives of their respective fields, but they neither individually nor as a whole demand this particular architecture. As many have pointed out, most if not all of the officially stated goals for Gateway can be accomplished more cheaply in other ways. But they are not the real purpose of Gateway, merely the smoke and mirrors for the politicians. Gateway, like the Asteroid Redirect Mission before it, has always been a Trojan horse to give NASA an excuse to fund its (semi-official) program of record for landing humans on Mars. The politicians are not willing to drop $billions on Mars technology development because the political payoff is too far out. But by selling them on a Rube Goldberg plan for exploring the moon (or near-Earth asteroids, etc.) that "just happens" to revolve around a space station which is a thinly disguised technology demonstrator for the "Deep Space Transport" vessel at the heart of the Mars program of record, they can get the funding they need move the ball forward on Mars.

This is something Jim Bridenstine hinted at a lot when he talked about why the agency (and he personally) felt the Gateway was so important. The most important thing, he kept saying - more important than the scientific/engineering "goals" listed on the PowerPoints - was that it would create the programmatic and political momentum needed to build a long-term beyond-Earth-orbit human spaceflight program that Congress couldn't (and wouldn't want to) cancel as soon as a flag was planted. NASA had learned the political lessons of the ISS vs. Apollo; one had staying power, the other didn't. The ISS was very unpopular with Congress when it was first created (it originally passed the House by one vote); but the combination of astronauts continuously up in space "right now" who "need to be taken care of", and (real or perceived) diplomatic concerns about losing a successful international partnership, proved to be a powerful psychological force that turned the ISS from a white elephant into a sacred cow for Congress.

(I'm convinced that this is the biggest real reason why NASA is always so careful - even to the point of jumping through diplomatic hoops to keep Americans flying on Soyuz even in the absence of a formal exchange agreement - to be extra sure that the ISS is never left without an American on board at any time. Setting aside the "record book" prestige implications of continuous occupation, if the ISS were ever without an American for, say, a month or two due to a contingency that required a vehicle to come home early, that would risk breaking the psychological dam that makes the continuation of the ISS such an imperative in Congress's minds. Once the idea of part-time occupation became mentally real to Congress, they'd start cooking up ideas to cut the budget, much like we're seeing Russia do now as they envision ROSS as a part-time-crewed station. And from there, it's just a matter of time before you end up like after Apollo 17 and Congress asks "why can't we just take a break while we divert the money to a development program for the Next Big Thing". Meanwhile delays mount, and we end up with another 10-year gap in human spaceflight.)

So, the real purpose of Gateway is to create that same kind of "positive feedback loop" with a program that will be "too good for Congress to let go of". Congress loves the sunk cost fallacy. The trick for NASA is to exploit that for positive gain (programs that accomplish a lot and provide a jumping-off point to accomplish even more - like the ISS) instead of letting that natural tendency take the path of least resistance (programs that sink endless resources into development with massive delays that barely seem to matter to Congress - like a certain big orange rocket). Gateway, as evolved from the Asteroid Redirect Mission, seems to be the result of NASA finally figuring out how to make the sunk cost fallacy work for them, after learning the hard lessons of Constellation and its aftermath.
Title: Re: Gateway Discussion Thread
Post by: su27k on 10/20/2021 02:51 am
Staging: Do you mean "staging for Artemis missions" (where the PPE+HALO probably are moderately useful, but no more than that), or "staging for Mars"? Because as mentioned a few comments back, it makes absolutely no sense to stage Mars missions out of lunar orbit unless you have a sufficient lunar economy that a significant portion of your Mars mission's mass will originate from the Moon. Which isn't happening any time soon.

I haven't run the numbers, but I believe the "staging for Mars" rational works like this:
1. Mars mission will be launched on SLS
2. SLS is too expensive and launch cadence is too low to support a big launch campaign like those envisioned in DRM5
3. Thus the need to reduce the mass needed to launch, this leads NASA to Solar Electric Propulsion (SEP)
4. But it would take SEP forever to raise itself from LEO, thus the need to have a staging place near the edge of Earth's gravity well, you could use Lagrange point but NRHO works too.
5. Bonus this provides a destination for Orion given NASA would take literally decades to prepare for the Mars mission and Orion has no where to go, so "win-win"

TL;DR: It all started because NASA has a crap launch system and it goes downhill from there.
Title: Re: Gateway Discussion Thread
Post by: lrk on 10/20/2021 03:36 pm
Sorry for make question in an update only thread...
So, better here, ...has now the PPE part of Gateway 3 AEPS engines?
https://twitter.com/Maxar/status/1414584544301359104
Any idea of the reason?

I guess nobody ever answered this - the 3rd engine was added with the change to launch the HALO and PPE as a single co-manifested vehicle, as the PPE is now responsible for moving a significantly larger mass to NRHO. 
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 10/20/2021 04:46 pm
Sorry for make question in an update only thread...
So, better here, ...has now the PPE part of Gateway 3 AEPS engines?
https://twitter.com/Maxar/status/1414584544301359104
Any idea of the reason?

I guess nobody ever answered this - the 3rd engine was added with the change to launch the HALO and PPE as a single co-manifested vehicle, as the PPE is now responsible for moving a significantly larger mass to NRHO. 
The center AEPS engine replaces ESA's HEAT engine. Originally 4 AEPS were planned in a square around HEAT.

https://russianspaceweb.com/imp-ppb.html
PPE SEP listed below.
https://www.rocket.com/space/space-power-propulsion/solar-electric-propulsion
Title: Re: Gateway Discussion Thread
Post by: AS_501 on 11/10/2021 10:13 pm
Changing subjects for a moment, assuming the Sun is always 'visible' from the Gateway HALO orbit, will it be necessary for the Solar arrays to track the Sun as it done with ISS?  Will there be times when Gateway enters the Moon's shadow?
(Asked by novice orbital mechanic. :) )
Thx
Title: Re: Gateway Discussion Thread
Post by: freddo411 on 11/10/2021 11:27 pm
Researching and developing things costs money. This list would cost serious money. That money isn't available unless you get a lot of buy-in from across the agency and, to reduce the risk of cancellation, international partners. HSF gets more funding for development associated with actual crew flights than for tech-development without crew flights. If you want the above things done, you will not get adequate funding (or potentially, any funding) unless it's a significant part of the HSF program of record.

It sucks. It's not efficient. But it's just the reality of how Congress, WH, Agency and it's Centres interact.
☝ This. The official "scientific and engineering reasons" for building Gateway in NRHO may be "nice to have" from the perspectives of their respective fields, but they neither individually nor as a whole demand this particular architecture. As many have pointed out, most if not all of the officially stated goals for Gateway can be accomplished more cheaply in other ways. But they are not the real purpose of Gateway, merely the smoke and mirrors for the politicians. Gateway, like the Asteroid Redirect Mission before it, has always been a Trojan horse to give NASA an excuse to fund its (semi-official) program of record for landing humans on Mars. The politicians are not willing to drop $billions on Mars technology development because the political payoff is too far out. But by selling them on a Rube Goldberg plan for exploring the moon (or near-Earth asteroids, etc.) that "just happens" to revolve around a space station which is a thinly disguised technology demonstrator for the "Deep Space Transport" vessel at the heart of the Mars program of record, they can get the funding they need move the ball forward on Mars.

This is something Jim Bridenstine hinted at a lot when he talked about why the agency (and he personally) felt the Gateway was so important. The most important thing, he kept saying - more important than the scientific/engineering "goals" listed on the PowerPoints - was that it would create the programmatic and political momentum needed to build a long-term beyond-Earth-orbit human spaceflight program that Congress couldn't (and wouldn't want to) cancel as soon as a flag was planted. NASA had learned the political lessons of the ISS vs. Apollo; one had staying power, the other didn't. The ISS was very unpopular with Congress when it was first created (it originally passed the House by one vote); but the combination of astronauts continuously up in space "right now" who "need to be taken care of", and (real or perceived) diplomatic concerns about losing a successful international partnership, proved to be a powerful psychological force that turned the ISS from a white elephant into a sacred cow for Congress.

(I'm convinced that this is the biggest real reason why NASA is always so careful - even to the point of jumping through diplomatic hoops to keep Americans flying on Soyuz even in the absence of a formal exchange agreement - to be extra sure that the ISS is never left without an American on board at any time. Setting aside the "record book" prestige implications of continuous occupation, if the ISS were ever without an American for, say, a month or two due to a contingency that required a vehicle to come home early, that would risk breaking the psychological dam that makes the continuation of the ISS such an imperative in Congress's minds. Once the idea of part-time occupation became mentally real to Congress, they'd start cooking up ideas to cut the budget, much like we're seeing Russia do now as they envision ROSS as a part-time-crewed station. And from there, it's just a matter of time before you end up like after Apollo 17 and Congress asks "why can't we just take a break while we divert the money to a development program for the Next Big Thing". Meanwhile delays mount, and we end up with another 10-year gap in human spaceflight.)

So, the real purpose of Gateway is to create that same kind of "positive feedback loop" with a program that will be "too good for Congress to let go of". Congress loves the sunk cost fallacy. The trick for NASA is to exploit that for positive gain (programs that accomplish a lot and provide a jumping-off point to accomplish even more - like the ISS) instead of letting that natural tendency take the path of least resistance (programs that sink endless resources into development with massive delays that barely seem to matter to Congress - like a certain big orange rocket). Gateway, as evolved from the Asteroid Redirect Mission, seems to be the result of NASA finally figuring out how to make the sunk cost fallacy work for them, after learning the hard lessons of Constellation and its aftermath.

That’s a very honest and compelling explanation.   Unfortunately, that might get you a gateway in NRHO that is very rarely visited by an astronomically expensive, tiny capsule atop an equally expensive expendable rocket.   Truly a low value proposition.

If that is all that the HSF program did for 2 or 3 decades, that would represent a huge lost opportunity.

A more compelling alternative is on display in Boca Chica.  Kudos to those in NASA that realize that a small part of NASA HSF funding can accomplish amazing new groundbreaking engineering, science and political goals
Title: Re: Gateway Discussion Thread
Post by: Steven Pietrobon on 11/11/2021 06:09 am
Changing subjects for a moment, assuming the Sun is always 'visible' from the Gateway HALO orbit, will it be necessary for the Solar arrays to track the Sun as it done with ISS?  Will there be times when Gateway enters the Moon's shadow?
(Asked by novice orbital mechanic. :) )
Thx

As gateway is orbiting the Moon, there should be times when it is shadowed by the Moon. This will occur around when the Moon is half-full. During full or new Moons, there should be no shadowing.
Title: Re: Gateway Discussion Thread
Post by: tbellman on 11/11/2021 09:11 am
As gateway is orbiting the Moon, there should be times when it is shadowed by the Moon. This will occur around when the Moon is half-full. During full or new Moons, there should be no shadowing.

There should be occasional periods of Earth shadowing as well.  I suppose they would happen roughly as often as (but not always coincident with) lunar eclipses.  Always at full moons, though.
Title: Re: Gateway Discussion Thread
Post by: pochimax on 11/11/2021 10:54 am
I guess nobody ever answered this - the 3rd engine was added with the change to launch the HALO and PPE as a single co-manifested vehicle, as the PPE is now responsible for moving a significantly larger mass to NRHO.

Thanks.

I don' t remember well... did Aerojet Rocketdyne made 4 AEPS engines? So now they are putting there 3 of the (previously planned) four?
Title: Re: Gateway Discussion Thread
Post by: Jim on 11/11/2021 12:39 pm
I guess nobody ever answered this - the 3rd engine was added with the change to launch the HALO and PPE as a single co-manifested vehicle, as the PPE is now responsible for moving a significantly larger mass to NRHO.

Thanks.

I don' t remember well... did Aerojet Rocketdyne made 4 AEPS engines? So now they are putting there 3 of the (previously planned) four?

there are 7 total engines.  4 are outboard.
Title: Re: Gateway Discussion Thread
Post by: primer_black on 11/11/2021 01:50 pm
Changing subjects for a moment, assuming the Sun is always 'visible' from the Gateway HALO orbit, will it be necessary for the Solar arrays to track the Sun as it done with ISS?  Will there be times when Gateway enters the Moon's shadow?
(Asked by novice orbital mechanic. :) )
Thx

As gateway is orbiting the Moon, there should be times when it is shadowed by the Moon. This will occur around when the Moon is half-full. During full or new Moons, there should be no shadowing.

In terms of frequency, the gateway will not see full eclipses often. Due to the complex motion, the station will only be in full eclipse about once a year for ~90 minutes at a time.
Title: Re: Gateway Discussion Thread
Post by: deadman1204 on 11/11/2021 02:41 pm
Changing subjects for a moment, assuming the Sun is always 'visible' from the Gateway HALO orbit, will it be necessary for the Solar arrays to track the Sun as it done with ISS?  Will there be times when Gateway enters the Moon's shadow?
(Asked by novice orbital mechanic. :) )
Thx
Even if its mostly in the sun, won't the angle of sunlight change? This would require the panels to track
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 11/11/2021 03:10 pm
Changing subjects for a moment, assuming the Sun is always 'visible' from the Gateway HALO orbit, will it be necessary for the Solar arrays to track the Sun as it done with ISS?  Will there be times when Gateway enters the Moon's shadow?
(Asked by novice orbital mechanic. :) )
Thx
Even if its mostly in the sun, won't the angle of sunlight change? This would require the panels to track
ISS is an Earth observation platform (among other duties). Gateway is not really a Moon observation platform because NRHO is a really bad location for that. Therefore, there is no particular reason for Gateway to orient on the Moon. Just keep the entire Gateway oriented with its panels facing the Sun.
Title: Re: Gateway Discussion Thread
Post by: pochimax on 11/11/2021 04:15 pm
I guess nobody ever answered this - the 3rd engine was added with the change to launch the HALO and PPE as a single co-manifested vehicle, as the PPE is now responsible for moving a significantly larger mass to NRHO.

Thanks.

I don' t remember well... did Aerojet Rocketdyne made 4 AEPS engines? So now they are putting there 3 of the (previously planned) four?

there are 7 total engines.  4 are outboard.

4 of the engines are BHT-6000, the other 3 AEPS, from Aerojet. Anyway, i now think AR has not made yet the engines... I thought the original 4 AEPS were made long ago, but now I don' t think so, while reviewing this tweet.

https://www.busek.com/bht6000 (https://www.busek.com/bht6000)

https://twitter.com/AerojetRdyne/status/1424802682901078019

Title: Re: Gateway Discussion Thread
Post by: cohberg on 11/11/2021 06:29 pm
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.

What is the module attached to I-HAB with all the exposed pallets?
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 11/11/2021 08:10 pm
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.

Love how the lander shown isn't the one actually selected.
Title: Re: Gateway Discussion Thread
Post by: dchenevert on 11/11/2021 09:15 pm
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.

Love how the lander shown isn't the one actually selected.

When NASA releases an image of Gateway docked with Starship I'm going to absolutely lose my <ability to be civil>.
Title: Re: Gateway Discussion Thread
Post by: jdon759 on 11/12/2021 02:50 am
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.
Love how the lander shown isn't the one actually selected.
It looks pretty generic, not really based on any of the proposals.  Probably to avoid legal issues.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 11/12/2021 03:14 am
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.
Love how the lander shown isn't the one actually selected.
It looks pretty generic, not really based on any of the proposals.  Probably to avoid legal issues.
I'm guessing it's trying to be the "Advanced Exploration Lander", which (apparently) was NASA's reference concept design during the initial NextSTEP solicitation for HLS designs in 2018.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 11/12/2021 04:51 am
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.
Love how the lander shown isn't the one actually selected.
It looks pretty generic, not really based on any of the proposals.  Probably to avoid legal issues.


It looks similar to the National Team's three elements lander. Which is mostly based on the reference NASA design. The flicker image might be a really old generic NASA reference design for a Moon lander.
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 11/12/2021 06:04 am
None of which answers Cohberg's original question.

But perhaps it suggests that the mystery module is a generic stand-in for something else, such as the proposed airlock module?
Title: Re: Gateway Discussion Thread
Post by: woods170 on 11/12/2021 08:52 am
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.

What is the module attached to I-HAB with all the exposed pallets?

That is the newly proposed non-Russian docking-and-airlock module.
Remember, orginally NASA wanted Russia to provide an airlock module (featuring an additional docking port). Rogozin et al. said no. But Gateway still needs an airlock module with additional docking port. So right now NASA, ESA and JAXA are looking into using a modified IHab design for the airlock/docking module.
That's reflected in the latest updated Gateway renders.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 11/12/2021 08:54 am
None of which answers Cohberg's original question.

But perhaps it suggests that the mystery module is a generic stand-in for something else, such as the proposed airlock module?

You're spot on.
See my reply #159 immediately above this one.
Title: Re: Gateway Discussion Thread
Post by: woods170 on 11/12/2021 06:17 pm
That is the newly proposed non-Russian docking-and-airlock module.

This is not the LEIA (Lightweight External Inflatable Airlock) inflatable concept, correct?
Any public literature about it?

(Assuming it is an airlock and iHab based)

I believe that iHab is still currently planned as a comanifest on Aremis 4 ($2+ billion launch cost). It is amazing to think that there are still people who think that its a good deal to pay another $2+ billion to ship an airlock (use the coupon code FREEORIONSHIPPING to also add transport for crew) when something starship sized / capable will be sitting right there docked to gateway. /s


Correct. This is not LEIA.
Title: Re: Gateway Discussion Thread
Post by: Jim on 11/12/2021 08:34 pm

I believe that iHab is still currently planned as a comanifest on Aremis 4 ($2+ billion launch cost). It is amazing to think that there are still people who think that its a good deal to pay another $2+ billion to ship an airlock (use the coupon code FREEORIONSHIPPING to also add transport for crew) when something starship sized / capable will be sitting right there docked to gateway


A "cargo" Starship does not exist at this time
There is nothing to plan to for Starship.  What are the payload interfaces or accommodations?  What are the payload environments?
A launch site on the east coast is TBD. 
Title: Re: Gateway Discussion Thread
Post by: fthomassy on 11/12/2021 09:15 pm
NASA Johnson (https://www.flickr.com/photos/nasa2explore/) released some additional renders of gateway.

Love how the lander shown isn't the one actually selected.
No lander has been selected for the “sustainable” presence missions with Gateway. What you see is NASA reference HLS.
Title: Re: Gateway Discussion Thread
Post by: AS_501 on 11/12/2021 09:32 pm
Several renders show modules with unused CBMs.  Is this done in accordance with proposed plans for expansion?  Or are CBMs provided even if there are no such plans?
Thx
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 11/13/2021 11:31 am
It is amazing to think that there are still people who think that its a good deal to pay another $2+ billion to ship an airlock [...] when something starship sized / capable will be sitting right there docked to gateway
A "cargo" Starship does not exist at this time

Cohberg was referring to the HLS-Starship, which is to be equipped with airlocks and up to four EVA suits, and docked with Gateway between missions.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 11/13/2021 02:35 pm
It is amazing to think that there are still people who think that its a good deal to pay another $2+ billion to ship an airlock [...] when something starship sized / capable will be sitting right there docked to gateway
A "cargo" Starship does not exist at this time

Cohberg was referring to the HLS-Starship, which is to be equipped with airlocks and up to four EVA suits, and docked with Gateway between missions.
I have seen no indication that each Starship HLS will have more than a single mission. That would require refueling in NRHO, which has not been discussed. Did I miss something?  Of course, the nominal end-of-mission for the uncrewed Starship HLS will leave it in NRHO, so it will already be there when the Gateway components arrive or when the HLS and Orion for Artemis 3 arrive. If they keep it up, the HLSs will begin to stack up to form a very large Gateway, so I assume they will either land them on the Moon (if enough fuel) or crash them on the Moon.

Which is easier, sending fuel to NRHO, or sending the Starship HLS back to an Earth orbit for refueling?
Title: Re: Gateway Discussion Thread
Post by: oldAtlas_Eguy on 11/13/2021 08:11 pm
It is amazing to think that there are still people who think that its a good deal to pay another $2+ billion to ship an airlock [...] when something starship sized / capable will be sitting right there docked to gateway
A "cargo" Starship does not exist at this time

Cohberg was referring to the HLS-Starship, which is to be equipped with airlocks and up to four EVA suits, and docked with Gateway between missions.
I have seen no indication that each Starship HLS will have more than a single mission. That would require refueling in NRHO, which has not been discussed. Did I miss something?  Of course, the nominal end-of-mission for the uncrewed Starship HLS will leave it in NRHO, so it will already be there when the Gateway components arrive or when the HLS and Orion for Artemis 3 arrive. If they keep it up, the HLSs will begin to stack up to form a very large Gateway, so I assume they will either land them on the Moon (if enough fuel) or crash them on the Moon.

Which is easier, sending fuel to NRHO, or sending the Starship HLS back to an Earth orbit for refueling?
You need practically the same amount of prop for either round trip to surface and back or a return to LEO. So it does not matter other than to resupply the LSS (HLS) cargo and supplies such that the going back to LEO works out better. You need a Tanker to go to NRHO transfer prop and then do a hot direct reentry back to Earth. A Tanker can be sent to NRHO for which it would have ~400t of prop. Almost enough to fuel 2 LSS returns to LEO. Add a depot and the tanker arrives transfers it's excess prop and promptly returns. Such that for every 2 Tanker trips an LSS can do not only it's initial trip to the surface but a second one as well then fuel up for a return to LEO. Such that for overall costs are lowered by 25% per Lunar landing.

In the case where passengers ride to and from LEO in the LSS you would only need to decouple the on orbit refueling ops until such time they become ironed out from having humans onboard by having them wait in the Gateway while the LSS is refueling. There would be a lot of backup safty considerations in the operations so that the ability to get crews back to LEO is lower risk in that having 2 LSS at the Gateway. One refueled and ready to return to Earth and has been that way for the last 200 days. And the other that is returning from the surface, docks and transfers off it crews, then goes to the depot to fuel up, then returns back to the Gateway prior to the other LSS departure from the Gateway. In this way the Gateway continuous occupancy as well as 2 Surface landings a year can be supported with the same costs as that of just the surface Landings. It just needs the LSS to stay at or around the Moon, surface then at the Gateway, for 6 months to a year before returning to LEO. In 3 years 6 LSS trips from LEO and 4 Tanker's from Earth to the NRHO depot.

NOTE is that the above paragraph is highly speculative and may have very little to do with how things actually end up evolving. It is just to show how the effect of a NRHO depot could make on Gateway and surface ops.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 11/14/2021 01:08 pm
<snip>
I have seen no indication that each Starship HLS will have more than a single mission. That would require refueling in NRHO, which has not been discussed. Did I miss something?  Of course, the nominal end-of-mission for the uncrewed Starship HLS will leave it in NRHO, so it will already be there when the Gateway components arrive or when the HLS and Orion for Artemis 3 arrive. If they keep it up, the HLSs will begin to stack up to form a very large Gateway, so I assume they will either land them on the Moon (if enough fuel) or crash them on the Moon.

Which is easier, sending fuel to NRHO, or sending the Starship HLS back to an Earth orbit for refueling?


AIUI NASA is buying two HLS Moonship landing missions to the Lunar surface. The hardware stills belongs to SpaceX . Who might decide to continue operating the Moonships for paying customers.


In theory the HLS Moonship could be use as a space tug to transfer modules/cargo to various Lunar orbits from LEO. SpaceX might build additional variant Moonships without landing hardware for cislunar logistics (retiring the Falcon Heavy).


Eventually SpaceX will have propellant depots at the various cislunar destinations. Presuming there is customer demand.


Tanker Starships will be cheap and useful for testing hardware and operational techniques.

Title: Re: Gateway Discussion Thread
Post by: ulm_atms on 11/25/2021 03:39 pm
My google-fu is lacking as I cannot find out the answer to this question....

Does anyone know the total wet weight of the PPE/HALO module?
Title: Re: Gateway Discussion Thread
Post by: Steven Pietrobon on 11/27/2021 06:09 am
I don't believe that number has been published. Someone was estimating 12-13 t total mass in a reply to this Spacenews article [1], but I think that is too low. The PPE mass is 8.6 t [2]. I estimate an expendable FH can deliver 20.8 t to TLI. HALO is pretty large and could easily mass 9 t as well. So my guess is 18 t total.

[1] https://spacenews.com/nasa-issues-contract-to-northrop-grumman-for-gateway-module/
[2] https://www.americaspace.com/2021/03/31/maxar-busek-conclude-end-to-end-testing-of-sep-system-for-lunar-gateway-element/
Title: Re: Gateway Discussion Thread
Post by: lykos on 11/27/2021 01:02 pm
HALO is directly based on Cygnus cargo module (weight 3.4 t), with some extras (docking port, batteries and others) maybe 4,5 - 5 t
Title: Re: Gateway Discussion Thread
Post by: woods170 on 11/27/2021 03:50 pm
HALO is directly based on Cygnus cargo module (weight 3.4 t), with some extras (docking port, batteries and others) maybe 4,5 - 5 t
More like 7 t to 7.5 t with all the internal fittings.
Title: Re: Gateway Discussion Thread
Post by: lrk on 11/29/2021 06:34 pm
HALO is directly based on Cygnus cargo module (weight 3.4 t), with some extras (docking port, batteries and others) maybe 4,5 - 5 t

But also minus the solar arrays and propulsion systems.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 03/14/2022 12:23 pm
https://twitter.com/tsr/status/1503073165316079617
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 03/23/2022 01:45 pm
In his 2018 Space Symposium speech, VP Pence spoke about a fuel depot at Gateway. More specifically, he said the following at 17 minutes of the video:

Quote from: VP Pence
NASA will lead the way back to the Moon, starting with the construction of a lunar orbital platform, the Gateway, which will provide a scientific outpost/supply center and eventually a fuel depot and will give our nation a strategic presence in the lunar domain.

youtu.be/FoXdLGmf9-A

I wonder if that is still part of the plan. It should be, especially for the landers.
Title: Re: Gateway Discussion Thread
Post by: deadman1204 on 03/23/2022 03:38 pm
I'm not a fan of the way some journalists push the gateway as being a waste. Yes, its not a full moon base, but it ignores the fact that a real moon base isn't gonna happen in the near future.

There are ZERO countries capable of doing this currently. Can it happen in the future?, sure eventually. Right now we have ZERO human landing capabilities on the moon and will probably only have 1 before the decade ends. However, human landing capabilities ARE NOT the same as base building capabilities (or the huge financial backing to do so).


The Gateway will stimulate Europe and Japan to develop the capabilities to LEAVE earth orbit and everything that goes along with it. While the Gateway is less sexy than a moonbase, its also alot more real.
Title: Re: Gateway Discussion Thread
Post by: wannamoonbase on 03/23/2022 03:44 pm
I'm not a fan of the way some journalists push the gateway as being a waste. Yes, its not a full moon base, but it ignores the fact that a real moon base isn't gonna happen in the near future.

There are ZERO countries capable of doing this currently. Can it happen in the future?, sure eventually. Right now we have ZERO human landing capabilities on the moon and will probably only have 1 before the decade ends. However, human landing capabilities ARE NOT the same as base building capabilities (or the huge financial backing to do so).


The Gateway will stimulate Europe and Japan to develop the capabilities to LEAVE earth orbit and everything that goes along with it. While the Gateway is less sexy than a moonbase, its also alot more real.

Having a deep space Space Station is cool in itself.  My take on the way NASA has been developing things since the Columbia disaster is they build a piece at a time.  Apollo they had the funds and mandate to do everything at once.

It took them decades to adapt to not having those funds, so now they have done Orion, then SLS, then Gateway, then HLS.  (excluding the fact that 10-20 years ago no one could have seen reuseable commercial rockets as a cheaper alternative).

Maybe the Gateway becomes a permanent fixture, maybe it's a step to a permanent base then abandoned.  Time will tell, but if it gets us beyond LEO, I support it.

I look forward to having crews orbiting the moon.
Title: Re: Gateway Discussion Thread
Post by: Hog on 03/23/2022 04:42 pm
I'm not a fan of the way some journalists push the gateway as being a waste. Yes, its not a full moon base, but it ignores the fact that a real moon base isn't gonna happen in the near future.

There are ZERO countries capable of doing this currently. Can it happen in the future?, sure eventually. Right now we have ZERO human landing capabilities on the moon and will probably only have 1 before the decade ends. However, human landing capabilities ARE NOT the same as base building capabilities (or the huge financial backing to do so).


The Gateway will stimulate Europe and Japan to develop the capabilities to LEAVE earth orbit and everything that goes along with it. While the Gateway is less sexy than a moonbase, its also alot more real.

Having a deep space Space Station is cool in itself.  My take on the way NASA has been developing things since the Columbia disaster is they build a piece at a time.  Apollo they had the funds and mandate to do everything at once.

It took them decades to adapt to not having those funds, so now they have done Orion, then SLS, then Gateway, then HLS.  (excluding the fact that 10-20 years ago no one could have seen reuseable commercial rockets as a cheaper alternative).

Maybe the Gateway becomes a permanent fixture, maybe it's a step to a permanent base then abandoned.  Time will tell, but if it gets us beyond LEO, I support it.

I look forward to having crews orbiting the moon.
10 years ago is 2012.
I want Gateway to stimulate Beyond Earth Orbit activities, just like NASA was and is selling, "Moon First" then......
Title: Re: Gateway Discussion Thread
Post by: deadman1204 on 03/23/2022 05:22 pm

10 years ago is 2012.
I want Gateway to stimulate Beyond Earth Orbit activities, just like NASA was and is selling, "Moon First" then......
honestly, thats all NASA can say until congress changes its tune. The cost to actually send people to Mars is SUPER high, and with things like SLS chained to NASA, they simply cannot afford it ever.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 05/02/2022 08:46 pm
This is strangely enough related to Gateway:
https://twitter.com/ninjaneergirl/status/1521140828759986177
Title: Re: Gateway Discussion Thread
Post by: deadman1204 on 05/03/2022 02:23 pm
This is strangely enough related to Gateway:
https://twitter.com/ninjaneergirl/status/1521140828759986177
Are they positioning the mounties to become the galactic police?
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 05/23/2022 08:11 pm
https://twitter.com/JimFree/status/1528824091360350216
Title: Re: Gateway Discussion Thread
Post by: VSECOTSPE on 05/23/2022 09:14 pm
https://twitter.com/JimFree/status/1528824091360350216

Quote
When we looked for the proper orbit for @NASA_Gateway, we were fortunate to have options. We could go high or low, but what if we could have the best of both, where we had both easy surface access and fuel efficiency? Enter the near-rectilinear halo orbit...

Misleading again from Free.  A low lunar orbit was never an option.  Orion lacks the dV.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 05/24/2022 12:21 am
I think that NASA's argument is that they didn't want to put Gateway in LLO anyways because it would require too much propellant to maintain it there.

Quote from: NASA
A spacecraft in low lunar orbit follows a circular or elliptical path very close to the lunar surface, completing an orbit every two hours. Transit between Gateway and the lunar surface would be quite simple in a low lunar orbit given their proximity, but because of the Moon’s gravity, more propellant is required to maintain the orbit. Therefore, low lunar orbit is not very efficient for Gateway’s planned long-term presence at the Moon – at least 15 years.
Title: Re: Gateway Discussion Thread
Post by: VSECOTSPE on 05/24/2022 11:51 pm
I think that NASA's argument is that they didn't want to put Gateway in LLO anyways because it would require too much propellant to maintain it there.

The mascon issue becomes negligible above 100km, vice the 3000km to 70000km Gateway altitude on its NRHO.  Even below 100km, there are frozen lunar orbits at four inclinations where mascon and other effects cancel each other out.  IIRC, there is even one around 85 degrees that passes over the poles.
Title: Re: Gateway Discussion Thread
Post by: Paul451 on 05/25/2022 04:58 am
I think that NASA's argument is that they didn't want to put Gateway in LLO anyways because it would require too much propellant to maintain it there.
The mascon issue becomes negligible above 100km, vice the 3000km to 70000km Gateway altitude on its NRHO.  Even below 100km, there are frozen lunar orbits at four inclinations where mascon and other effects cancel each other out.  IIRC, there is even one around 85 degrees that passes over the poles.

And before we reflexively go through the predictable next objections in this oft-repeated chain, let's jump straight to the predictable responses: No, communications wasn't the issue either. The cost of a relay sat or two in the same orbit as the station would be trivial on the scale of the rest of Artemis, and would be more useful for other surface instruments. And no, it isn't emergency return-to-station, because a lower orbit would be so much easier for ascent stages that there'd be more capacity for fast return.

(Can't remember the next step in the chain.)
Title: Re: Gateway Discussion Thread
Post by: su27k on 06/30/2022 03:19 am
https://twitter.com/RussianSpaceWeb/status/1542120761611231234

Quote
What struck me most about this strange presentation of the Lunar Gateway is that Northrop Grumman decided to copy my rendering of an internal Russian lunar lander concept that I created for Popular Mechanics around 2015. Try find differences: https://russianspaceweb.com/lvpk.html
Title: Re: Gateway Discussion Thread
Post by: redliox on 07/05/2022 07:04 pm
The Capstone mission might be in jeopardy after launch.  Communication died not long after separating from its launcher.  I hope for the best, but I bring this up here because the mission was largely meant to test the orbit Gateway might occupy.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 07/07/2022 10:59 pm
The Capstone mission might be in jeopardy after launch.  Communication died not long after separating from its launcher.  I hope for the best, but I bring this up here because the mission was largely meant to test the orbit Gateway might occupy.
Update for CAPSTONE. Apparently communication is restored, although the cause of the outage hasn't been determined yet.
Title: Re: Gateway Discussion Thread
Post by: Kiwi53 on 07/11/2022 10:40 pm
The Capstone mission might be in jeopardy after launch.  Communication died not long after separating from its launcher.  I hope for the best, but I bring this up here because the mission was largely meant to test the orbit Gateway might occupy.
Update for CAPSTONE. Apparently communication is restored, although the cause of the outage hasn't been determined yet.

The cause was established on 7th July, see https://forum.nasaspaceflight.com/index.php?topic=50152.msg2384072#msg2384072 (https://forum.nasaspaceflight.com/index.php?topic=50152.msg2384072#msg2384072)
Quote
the spacecraft operations team attempted to access diagnostic data on the spacecraft’s radio and sent an improperly formatted command that made the radio inoperable. The spacecraft fault detection system should have immediately rebooted the radio but did not because of a fault in the spacecraft flight software.
CAPSTONE’s autonomous flight software system eventually cleared the fault and brought the spacecraft back into communication with the ground, allowing the team to implement recovery procedures and begin commanding the spacecraft again. 
Title: Re: Gateway Discussion Thread
Post by: eeergo on 07/19/2022 08:47 pm
Another day at the office, this time looking at the structure for HALO getting welded with NASA's Jim Free, including a look through the CBM hatches... I've tapped it now a couple dozen times when clocking in every morning :)

https://mobile.twitter.com/NASA_Gateway/status/1549490404697014275 (https://mobile.twitter.com/NASA_Gateway/status/1549490404697014275)


https://mobile.twitter.com/JimFree/status/1549460016402276353
Title: Re: Gateway Discussion Thread
Post by: russianhalo117 on 07/19/2022 09:28 pm
Another day at the office, this time looking at the structure for HALO getting welded with NASA's Jim Free, including a look through the CBM hatches... I've tapped it now a couple dozen times when clocking in every morning :)

https://mobile.twitter.com/NASA_Gateway/status/1549490404697014275 (https://mobile.twitter.com/NASA_Gateway/status/1549490404697014275)


https://mobile.twitter.com/JimFree/status/1549460016402276353
Scaled down CBM tunnel taken from Cygnus hatch dimensions for IDSS compliant NDS docking/GERS active-active Robotic berthing. NDS will be bolted on after module  ground outfitting and potentially welded for increased module lifetime (depends on decision during the next DAC).
Title: Re: Gateway Discussion Thread
Post by: pochimax on 07/22/2022 09:43 am
Another day at the office, this time looking at the structure for HALO getting welded with NASA's Jim Free, including a look through the CBM hatches... I've tapped it now a couple dozen times when clocking in every morning :)

So, what is this? I thought this was HALO module. Is that a Cygnus, instead? This tweet is unclear.

"...mostrandogli i primi elementi del futuro ecosistema #lunare."

https://twitter.com/Thales_Alenia_S/status/1547516628874760194

Is it possible this other images are from i-Hab, instead of HALO?

"...as I-HAB’s structure takes shape."

https://twitter.com/JimFree/status/1549460359387365377

Thanks

Title: Re: Gateway Discussion Thread
Post by: ar1978 on 07/26/2022 07:06 pm
https://www.cnn.com/2022/07/26/world/russia-quit-iss-scn/index.html

https://www.cnn.com/2022/07/26/world/russia-quit-iss-scn/index.html

https://www.youtube.com/watch?v=101Lbw9YTzg

Given the news today of the Russians leaving the ISS and the more recent articles stating that an ISS replacement won't be ready by 2030, would it be time to re-evaluate whether the Lunar Gateway in a NRHO orbit makes sense?

Instead could you just put it into LEO, and have it be a staging point for Lunar missions from there? That way we could use the Crew Dragon and Starliner to get astronauts there. I searched around on this forum before asking this and a lot of the posts on the Gateway are hostile. Also included a link to a debate b/w Robert Zubrin and Greg Autry which is an interesting watch. I'm just wondering the Gateway in LEO if this is a viable alternative or if keeping it in NHRO is still a better option. Or would another option be to just ad more modules to the Gateway in NRHO and have people there full time starting around 2030 when the ISS reaches its end of life?

Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/26/2022 07:48 pm
I’d rather be stuck in lunar orbit than LEO again.
Title: Re: Gateway Discussion Thread
Post by: yg1968 on 07/26/2022 07:57 pm
Given the news today of the Russians leaving the ISS and the more recent articles stating that an ISS replacement won't be ready by 2030, would it be time to re-evaluate whether the Lunar Gateway in a NRHO orbit makes sense?

Instead could you just put it into LEO, and have it be a staging point for Lunar missions from there? That way we could use the Crew Dragon and Starliner to get astronauts there. I searched around on this forum before asking this and a lot of the posts on the Gateway are hostile. Also included a link to a debate b/w Robert Zubrin and Greg Autry which is an interesting watch. I'm just wondering the Gateway in LEO if this is a viable alternative or if keeping it in NHRO is still a better option. Or would another option be to just ad more modules to the Gateway in NRHO and have people there full time starting around 2030 when the ISS reaches its end of life?

The Russians say that they are leaving ISS after 2024. Jeff Foust says that the after in this sentence is key here, it may not be in 2024.

In any event, it would make more sense to accelerate the Commercial Lunar Destinations program than use Gateway.
Title: Re: Gateway Discussion Thread
Post by: jstrotha0975 on 07/26/2022 08:23 pm
One of these decades NASA is going to have to learn how to walk and chew bubble gum at the same time.
Title: Re: Gateway Discussion Thread
Post by: shintoo on 07/26/2022 10:21 pm
Gateway assembly animation newly uploaded to the NASA Johnson YouTube channel. Shows PPE+Halo arrival, Orion delivering I-Hab, ESPRIT, and airlock, and multiple HLS and GLS dockings, including one delivering Canadarm3.

https://www.youtube.com/watch?v=Pme6SrG_-ZA (2m49s)
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 07/27/2022 04:25 pm

Given the news today of the Russians leaving the ISS and the more recent articles stating that an ISS replacement won't be ready by 2030, would it be time to re-evaluate whether the Lunar Gateway in a NRHO orbit makes sense?

Instead could you just put it into LEO, and have it be a staging point for Lunar missions from there? That way we could use the Crew Dragon and Starliner to get astronauts there. I searched around on this forum before asking this and a lot of the posts on the Gateway are hostile. Also included a link to a debate b/w Robert Zubrin and Greg Autry which is an interesting watch. I'm just wondering the Gateway in LEO if this is a viable alternative or if keeping it in NHRO is still a better option. Or would another option be to just ad more modules to the Gateway in NRHO and have people there full time starting around 2030 when the ISS reaches its end of life?
Welcome to the forum. I see you are new here. A brief, cynical, incomplete, and  biased history:
Gateway is part of the Artemis program. Artemis is a fairly late iteration of a series of programs intended to provide job security for the work that started with the Space shuttle program. The US congress mandated that SLS be built to use parts from the Space Shuttle system. SLS needed a destination, and after several earlier ideas, the programs evolve to make Lunar gateway the destination for SLS/Orion. It is needed because SLS/Orion cannot actually land a crew on the Moon, or even get a crew to a low lunar orbit, so Gateway is the place where crew will transfer to the HLS. In the mean time, the components of what became Gateway are repurposed from several other cancelled programs.

If NASA transferred crew to HLS in LEO, then SLS, Orion, and Gateway would not be needed, and this wrecks the ongoing job security program.

For further study, look at :
  https://en.wikipedia.org/wiki/Artemis_program
and
  https://en.wikipedia.org/wiki/Lunar_Gateway
As always with Wikipedia (or any other information source), check the references, but I think the articles are reasonably balanced.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/27/2022 05:27 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.
Title: Re: Gateway Discussion Thread
Post by: deadman1204 on 07/27/2022 06:22 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.
Gateway is many things, of which this is one.
Title: Re: Gateway Discussion Thread
Post by: VSECOTSPE on 07/28/2022 12:21 am
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.

NASA has made statements to this effect, but it’s really not.  Both the scale of the propulsion and the duration of astronaut stays are off by an order of magnitude (10x).  It’s like saying a riding lawnmower is a prototype for an SUV.  Just not true.
Title: Re: Gateway Discussion Thread
Post by: shintoo on 07/28/2022 12:41 am
Regarding DST, I had always thought of Gateway more as "the place where maybe one day hopefully the DST could be assembled at". The only reason I can think of for DST being assembled at Gateway is that the space the DST elements provide there would be useful in the years building up to disembarking. It also lends itself to a shakedown cruise, and/or a Mars simulated mission using the DST at Gateway and a lunar surface sortie as a "pretend" Mars landing simulation.

It will be interesting to see the capabilities and intentions evolve over the years as deployment nears and construction progresses.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 02:43 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.

NASA has made statements to this effect, but it’s really not.  Both the scale of the propulsion and the duration of astronaut stays are off by an order of magnitude (10x).  It’s like saying a riding lawnmower is a prototype for an SUV.  Just not true.
Prototypes are often a pale shadow of what the final product would be, sometimes little more than a proof of concept. But it has everything the DST/MTV would have, just at smaller scale. Hence why I called it a prototype of DST, not a full up DST.

(IMHO, though, DST for Mars doesn’t make sense… it’s a bad architecture… but that’s another topic.)
Title: Re: Gateway Discussion Thread
Post by: VSECOTSPE on 07/28/2022 03:53 pm
Prototypes are often a pale shadow of what the final product would be, sometimes little more than a proof of concept. But it has everything the DST/MTV would have, just at smaller scale. Hence why I called it a prototype of DST, not a full up DST.

Confuses prototyping with scale model testing.  Gateway is neither with respect to DST.  It’s not a scale model to put in a wind tunnel or other testing chamber.  And both its propulsion (6kW Hall thrusters) and its life support (60-day stays) are an order of magnitude or more smaller than what DST requires (~300kW propulsion and ~1000-day stays).

Gateway is to DST what early lawnmowers and motorbikes are to later automobile manufacturers.  Honda, for example, built motorized bicycles for a decade or two before they built cars, but Honda never prototyped a new line of cars by building a motorized bike.
Title: Re: Gateway Discussion Thread
Post by: Coastal Ron on 07/28/2022 04:01 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.

NASA has made statements to this effect, but it’s really not.  Both the scale of the propulsion and the duration of astronaut stays are off by an order of magnitude (10x).  It’s like saying a riding lawnmower is a prototype for an SUV.  Just not true.
Prototypes are often a pale shadow of what the final product would be, sometimes little more than a proof of concept. But it has everything the DST/MTV would have, just at smaller scale. Hence why I called it a prototype of DST, not a full up DST.

(IMHO, though, DST for Mars doesn’t make sense… it’s a bad architecture… but that’s another topic.)

In the world of manufacturing a prototype demonstrates the final product, but may not use the components the final product will have.

The Gateway can't demonstrate what a Deep Space Transfer Vehicle can do, either wholly or in part. Gateway is more of a scale model of what a DST needs to be, but even that would be a generous description...  ;)
Title: Re: Gateway Discussion Thread
Post by: shintoo on 07/28/2022 04:09 pm
I think it's hard to say this early what aspects Gateway can prototype regarding DST, outside of the very little we already know. Technology is one thing, processes are another. For example, we haven't ever rehoused operational payloads from a station to a lander or surface hab. A crop growth rack on Gateway that's been operational for years - what is the process like transferring that to a permanent home on the surface?

When going to Mars, these payloads will either need to live their entire operational lives in the same vehicle, during transit and on the surface, or considerations will need to be made when designing and integrating their on-orbit/in-transit environments and their on-surface environments. For example, will our lander/surface hab have the same EXPRESS racks or analog used on Gateway? Resources available to payloads could change between those environments as well. All this is just scratching the surface, and can be ironed out with integrated Gateway + lunar surface missions.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 04:21 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.

NASA has made statements to this effect, but it’s really not.  Both the scale of the propulsion and the duration of astronaut stays are off by an order of magnitude (10x).  It’s like saying a riding lawnmower is a prototype for an SUV.  Just not true.
Prototypes are often a pale shadow of what the final product would be, sometimes little more than a proof of concept. But it has everything the DST/MTV would have, just at smaller scale. Hence why I called it a prototype of DST, not a full up DST.

(IMHO, though, DST for Mars doesn’t make sense… it’s a bad architecture… but that’s another topic.)

In the world of manufacturing a prototype demonstrates the final product, but may not use the components the final product will have.

The Gateway can't demonstrate what a Deep Space Transfer Vehicle can do, either wholly or in part. Gateway is more of a scale model of what a DST needs to be, but even that would be a generous description...  ;)
Nah, I know there’s a lot of hate for Gateway, but that’s just not true. It has high power electric propulsion, which I think has never been used on crewed vehicles before, and more than any other single vehicle. It will operate in deep space and will use that propulsion to move from Earth orbit to lunar orbit, demonstrating some of what the DST was supposed to do. It’ll be used as a basing point for landers, like what DST is supposed to do for Mars. It has habitation modules and will operate with human crew for moderate periods of time at first but could be more eventually (but what purpose would that serve, really, unless you’re doing a dry run for a Mars or asteroid mission?).

It actually is comparable to DST. The propulsion system is smaller, much smaller than pure SEP based DST, but about the same order of magnitude for the minimum size needed for a hybrid chemical/electric propulsion system (which has often been studied).

It’s just that… there’s no real need for the job the DST does, at least for Mars. That’s the main thing.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 07/28/2022 07:06 pm
<snip>
It’s just that… there’s no real need for the job the DST does, at least for Mars. That’s the main thing.
A full scale DST could do the job for a flag and footprint mission to Mars, if there was nothing better available. However there is something available.
Title: Re: Gateway Discussion Thread
Post by: Coastal Ron on 07/28/2022 08:59 pm
In the world of manufacturing a prototype demonstrates the final product, but may not use the components the final product will have.

The Gateway can't demonstrate what a Deep Space Transfer Vehicle can do, either wholly or in part. Gateway is more of a scale model of what a DST needs to be, but even that would be a generous description...  ;)
Nah, I know there’s a lot of hate for Gateway, but that’s just not true. It has high power electric propulsion, which I think has never been used on crewed vehicles before, and more than any other single vehicle. It will operate in deep space and will use that propulsion to move from Earth orbit to lunar orbit, demonstrating some of what the DST was supposed to do. It’ll be used as a basing point for landers, like what DST is supposed to do for Mars. It has habitation modules and will operate with human crew for moderate periods of time at first but could be more eventually (but what purpose would that serve, really, unless you’re doing a dry run for a Mars or asteroid mission?).

It actually is comparable to DST. The propulsion system is smaller, much smaller than pure SEP based DST, but about the same order of magnitude for the minimum size needed for a hybrid chemical/electric propulsion system (which has often been studied).

It’s just that… there’s no real need for the job the DST does, at least for Mars. That’s the main thing.

Remember the Nautilus-X (https://en.wikipedia.org/wiki/Nautilus-X)? The Non-Atmospheric Universal Transport Intended for Lengthy United States Exploration (Nautilus-X) was first proposed back in 2011, and its intent was to support long-duration space journeys (1 to 24 months) with a six-person crew.

Reusable, was projected to cost ~$4B back in 2011, and was an actual spaceship, not a repurposed space station.

Gateway may be a fine little space station, but let's not kid ourselves here, the Gateway is not breaking any ground for getting people to Mars.

And if the goal is to get to Mars, then NASA should focus on building an interplanetary spaceship, not a lunar space station. And any first generation interplanetary spaceship should start out making progressively longer and longer trips before taking off for distant destinations like Mars. Plus there should be more than one, ala like the Nina, Pinta, and Santa Maria (https://en.wikipedia.org/wiki/Voyages_of_Christopher_Columbus#First_voyage).

NASA focusing on figuring out (again) how to get to the surface of our Moon is a fine goal, but it is COMPLETELY separate from a Journey To Mars. Especially since no journey to Mars is worthwhile until you can land, and return from Mars. We won't learn that on a lunar-focused program.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 07/28/2022 09:21 pm
Gateway may be a fine little space station, but let's not kid ourselves here, the Gateway is not breaking any ground for getting people to Mars.

Gateway will provide an opportunity for long duration human spaceflight missions in deep space. That's not been accomplished before, and doing it is certainly a step on the way towards NASA's Mars ambitions.
Title: Re: Gateway Discussion Thread
Post by: butters on 07/28/2022 10:14 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.
Lunar Gateway: Prototype for Mars Transfer Vehicle or New Purpose for Asteroid Redirect Spacecraft?

Maybe a little of both?

The PPE wasn't even powerful enough to accommodate HALO being co-manifested on its launch, requiring a significant redesign that's apparently ongoing and not without struggles. If this a prototype for an MTV spacecraft bus, it's a very very subscale prototype. Especially if the Mars lander is Starship-sized, the MTV would need some serious SEP muscle, probably not directly derived from PPE technology. We'd need something more like what Ad Astra is working on with the VASIMR plasma engine.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 10:31 pm
The redirect craft was itself an iteration of the DST.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 10:34 pm
Gateway is actually essentially a prototype of the Deep Space Transfer Vehicle.
Lunar Gateway: Prototype for Mars Transfer Vehicle or New Purpose for Asteroid Redirect Spacecraft?

Maybe a little of both?

The PPE wasn't even powerful enough to accommodate HALO being co-manifested on its launch, requiring a significant redesign that's apparently ongoing and not without struggles. If this a prototype for an MTV spacecraft bus, it's a very very subscale prototype. Especially if the Mars lander is Starship-sized, the MTV would need some serious SEP muscle, probably not directly derived from PPE technology. We'd need something more like what Ad Astra is working on with the VASIMR plasma engine.
The step from uncrewed SEP systems to a full MTV SEP system was deemed one of the biggest technical risks for SEP MTV. The PPE is, from a logarithmic perspective, right in between a full SEP MTV and the previous robotic SEP systems.

VASIMR is a hype engine, and anyone in the electric propulsion field for more than a couple years thinks so. No, we need nothing like VASIMR.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 10:36 pm
In the world of manufacturing a prototype demonstrates the final product, but may not use the components the final product will have.

The Gateway can't demonstrate what a Deep Space Transfer Vehicle can do, either wholly or in part. Gateway is more of a scale model of what a DST needs to be, but even that would be a generous description...  ;)
Nah, I know there’s a lot of hate for Gateway, but that’s just not true. It has high power electric propulsion, which I think has never been used on crewed vehicles before, and more than any other single vehicle. It will operate in deep space and will use that propulsion to move from Earth orbit to lunar orbit, demonstrating some of what the DST was supposed to do. It’ll be used as a basing point for landers, like what DST is supposed to do for Mars. It has habitation modules and will operate with human crew for moderate periods of time at first but could be more eventually (but what purpose would that serve, really, unless you’re doing a dry run for a Mars or asteroid mission?).

It actually is comparable to DST. The propulsion system is smaller, much smaller than pure SEP based DST, but about the same order of magnitude for the minimum size needed for a hybrid chemical/electric propulsion system (which has often been studied).

It’s just that… there’s no real need for the job the DST does, at least for Mars. That’s the main thing.

Remember the Nautilus-X (https://en.wikipedia.org/wiki/Nautilus-X)? The Non-Atmospheric Universal Transport Intended for Lengthy United States Exploration (Nautilus-X) was first proposed back in 2011, and its intent was to support long-duration space journeys (1 to 24 months) with a six-person crew.

Reusable, was projected to cost ~$4B back in 2011, and was an actual spaceship, not a repurposed space station.

Gateway may be a fine little space station, but let's not kid ourselves here, the Gateway is not breaking any ground for getting people to Mars.

And if the goal is to get to Mars, then NASA should focus on building an interplanetary spaceship, not a lunar space station. And any first generation interplanetary spaceship should start out making progressively longer and longer trips before taking off for distant destinations like Mars. Plus there should be more than one, ala like the Nina, Pinta, and Santa Maria (https://en.wikipedia.org/wiki/Voyages_of_Christopher_Columbus#First_voyage).

NASA focusing on figuring out (again) how to get to the surface of our Moon is a fine goal, but it is COMPLETELY separate from a Journey To Mars. Especially since no journey to Mars is worthwhile until you can land, and return from Mars. We won't learn that on a lunar-focused program.
Nautilus X was a niche concept, not ever very serious. Look at DST or MTV concepts developed by NASA Langley for more serious designs. They’re somewhat similar to Gateway.

I think using a Mars Transfer Vehicle like that is an architecturally bad decision, tho.
Title: Re: Gateway Discussion Thread
Post by: Coastal Ron on 07/28/2022 10:45 pm
Gateway may be a fine little space station, but let's not kid ourselves here, the Gateway is not breaking any ground for getting people to Mars.

Gateway will provide an opportunity for long duration human spaceflight missions in deep space.

How? It never leaves lunar orbit.

And we are already doing long-duration human spaceflight missions on the ISS (up to a year), whereas due to the limitation of the Artemis missions, the Gateway is not intended for full-time occupancy.

Quote
That's not been accomplished before...

Partial testing has been done on the ISS, and the Gateway is not going to exceed what the ISS testing has done.

Quote
...and doing it is certainly a step on the way towards NASA's Mars ambitions.

That is NASA PR, not reality. We won't be taking a step towards Mars until we leave Earth-local space - BEO (beyond Earth orbit).

Unless Gateway is going to be staffed for a year or more, and take a journey outside of Earth-local space, it is not doing anything important for getting humans to Mars. That doesn't mean its not a nice little space station, but it won't be "critical" for the journey to Mars. Heck, NASA can't even go to Mars for a long time since it is so focused on the Moon right now, and there is a good chance the return-to-Moon flights won't even get there till the end of this decade due to delays in a whole host of important hardware.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 07/28/2022 10:58 pm
Gateway will provide an opportunity for long duration human spaceflight missions in deep space.

How? It never leaves lunar orbit.

And we are already doing long-duration human spaceflight missions on the ISS

Apparently I failed to emphasize the deep space part of my observation. LEO and beyond-LEO are very different environments. There's plenty of discussion of this here at NSF and at other reputable sites for anyone who cares to look.
Title: Re: Gateway Discussion Thread
Post by: Robotbeat on 07/28/2022 11:19 pm
There is no technical reason Gateway couldn’t host 6-12 month long human missions. It’d be cramped, potentially, but a small crew could be used. No different than stuff Salyut did.

But I don’t think it’s necessary.
Title: Re: Gateway Discussion Thread
Post by: lykos on 07/30/2022 02:40 pm
Exactly!
It won't be necessary at all!
There is nothing between earth, moon and mars what a Starship couldn't do better than any Gateway (or spaceship!)
Title: Re: Gateway Discussion Thread
Post by: Khadgars on 07/30/2022 03:26 pm
Exactly!
It won't be necessary at all!
There is nothing between earth, moon and mars what a Starship couldn't do better than any Gateway (or spaceship!)

I like Starship but to think it will replace everything between earth, moon and Mars is ridiculous. 
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 07/30/2022 03:54 pm
Exactly!
It won't be necessary at all!
There is nothing between earth, moon and mars what a Starship couldn't do better than any Gateway (or spaceship!)

I like Starship but to think it will replace everything between earth, moon and Mars is ridiculous.
Starship will only replace other spacecraft that are very clearly less capable of performing the function in which Starship is replacing them. Timing is important: if a non-Starship spacecraft is already designed and is being produced in time for a mission but the appropriate Starship is not, then clearly Starship cannot replace it. The opposite is also true.

To show that "replace everything" is ridiculous, all you need to do is identify a mission that another spacecraft can accomplish but that Starship cannot do better, taking schedule into account.
Title: Re: Gateway Discussion Thread
Post by: su27k on 07/31/2022 02:11 am
Exactly!
It won't be necessary at all!
There is nothing between earth, moon and mars what a Starship couldn't do better than any Gateway (or spaceship!)

I like Starship but to think it will replace everything between earth, moon and Mars is ridiculous.

He didn't say it'll replace everything, he said it'll be better than Gateway and - presumably - any Gateway derived spacecraft, which I think it's correct.
Title: Re: Gateway Discussion Thread
Post by: Coastal Ron on 07/31/2022 03:09 am
The Artemis Gateway is a political animal, and things created for political reasons tend to be compromises and NOT durable solutions.

Remember the goal of the Artemis program is to (https://www.nasa.gov/specials/artemis/) "...land the first woman and first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before."

The Gateway is supposed to support that goal, though it is hobbled by the transportation system the Artemis program uses to transport crew to the Moon (i.e. the SLS+Orion) - $1B per person, and it is only currently funded to go there once a year for a few weeks. Not only that, but the limitations of the SLS+Orion force the Gateway to be in a ~7 day polar near-rectilinear halo orbit (NRHO), which means the Gateway takes longer to circle the Moon than it takes to fly the crew from Earth to the Moon, AND back. Not optimal for safety reasons.

However political programs are measured by different criteria than commercial or non-profit ones, and usually money is not a primary consideration. We know this to be true for the SLS and Orion programs.

But unlike the SLS and Orion programs, the Gateway is being built as an international partnership, which means it has different goals than the SLS and Orion programs. That also means that if there is an alternative to the SLS and Orion for transporting crew to/from the Gateway, that could be added on top of the existing SLS and Orion flights.

In other words, I think there is a possibility for a parallel transportation to be incorporated into the Artemis program that would be in addition to the SLS+Orion, especially if the Artemis partners advocate for that.

And why might the Artemis partners advocate for that? Because it could mean that they would get more use out of their investment - more missions, and maybe for not much more cost.

I wonder if, in a future where the SLS+Orion are replaces by something with more capabilities, if the Gateway could be moved into a closer orbit to the Moon? Besides the cost of the energy to do that, any technical reasons why it couldn't? Just a thought...
Title: Re: Gateway Discussion Thread
Post by: Eric Hedman on 07/31/2022 05:28 am
I wonder if, in a future where the SLS+Orion are replaces by something with more capabilities, if the Gateway could be moved into a closer orbit to the Moon? Besides the cost of the energy to do that, any technical reasons why it couldn't? Just a thought...
There is no technical reason that I am aware of that it couldn't be moved.  Before the Gateway got funded for full development, there was plenty of discussion that it could move between, NRHO, LLO, L1 and L2 to wherever it would be needed at the time.  I don't think anything has changed that would prevent that.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 07/31/2022 01:58 pm

I wonder if, in a future where the SLS+Orion are replaces by something with more capabilities, if the Gateway could be moved into a closer orbit to the Moon? Besides the cost of the energy to do that, any technical reasons why it couldn't? Just a thought...
Apparently, the PPE (Power and Propulsion Element) is specifically designed to move stuff around with high efficiency, using ion engines. It will need to be refuelled, but presumably Dragon XL can do this. This assumes gateway as it evolves is designed to be accellerated by PPE. We know the initial gateway (PPE+HALO) is designed to be accelerated by PPE.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 07/31/2022 04:42 pm
Responding to query from the update thread

https://www.gao.gov/assets/gao-22-105212.pdf

Quote from: Page 51
As of February 2022, the co-manifested vehicle is above the Falcon
Heavy launch vehicle’s mass limit. If the mass is too high, it could affect
the vehicle’s ability to reach the correct lunar orbit. The project is taking
steps to reduce mass, including evaluating whether it needs to
potentially off-load some components for initial launch.
co-manifested vehicle = PPE + HALO
I don't understand this quote. Falcon Heavy was never supposed to put PPE+HALO into a lunar orbit in the first place. As I uderstand it, after FH puts PPE+HALO into orbit, PPE is supposed to move PPE+HALO into NRHO, taking about nine months to do so. If PPE+HALO is heavier, PPE will have more work to do. Worst case, PPE will need refuelling, but it is supposed to be designed for this, presumably from Dragon XL as part of GLS.

Guessing it might be the maximum mass the payload adapter on the Falcon upper stage is rated for. The integrated PPE & HALO stack is a lot of mass on top of a launcher going to LEO.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 07/31/2022 04:59 pm
Responding to query from the update thread

https://www.gao.gov/assets/gao-22-105212.pdf

Quote from: Page 51
As of February 2022, the co-manifested vehicle is above the Falcon
Heavy launch vehicle’s mass limit. If the mass is too high, it could affect
the vehicle’s ability to reach the correct lunar orbit. The project is taking
steps to reduce mass, including evaluating whether it needs to
potentially off-load some components for initial launch.
co-manifested vehicle = PPE + HALO
I don't understand this quote. Falcon Heavy was never supposed to put PPE+HALO into a lunar orbit in the first place. As I uderstand it, after FH puts PPE+HALO into orbit, PPE is supposed to move PPE+HALO into NRHO, taking about nine months to do so. If PPE+HALO is heavier, PPE will have more work to do. Worst case, PPE will need refuelling, but it is supposed to be designed for this, presumably from Dragon XL as part of GLS.

Guessing it might be the maximum mass the payload adapter on the Falcon upper stage is rated for. The integrated PPE & HALO stack is a lot of mass on top of a launcher going to LEO.
OK, but the quote does not say it cannot get to LEO. It says "it could affect the vehicle’s ability to reach the correct lunar orbit." Sure, failure to reach orbit at all would have that effect, but that's like saying that a fatal heart attack might affect your circulation.
Title: Re: Gateway Discussion Thread
Post by: sdsds on 07/31/2022 10:14 pm
PPE [...] will need to be refuelled, but presumably Dragon XL can do this.

Isn't refilling the PPE with propellant the job of ESPRIT?

Quote
A second contribution called Esprit, will supply enhanced communications, refuelling and a window
https://www.esa.int/ESA_Multimedia/Images/2020/10/What_is_Esprit
Title: Re: Gateway Discussion Thread
Post by: Jim on 07/31/2022 11:15 pm

Guessing it might be the maximum mass the payload adapter on the Falcon upper stage is rated for. The integrated PPE & HALO stack is a lot of mass on top of a launcher going to LEO.


That isn't an issue
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 07/31/2022 11:31 pm
PPE [...] will need to be refuelled, but presumably Dragon XL can do this.

Isn't refilling the PPE with propellant the job of ESPRIT?

Quote
A second contribution called Esprit, will supply enhanced communications, refuelling and a window
https://www.esa.int/ESA_Multimedia/Images/2020/10/What_is_Esprit
Apparently EPSRIT will become a permanent part of the Gateway. Among other functions it houses extra fuel tanks for PPE, but it does not actually bring refills.
   https://en.wikipedia.org/wiki/European_System_Providing_Refueling,_Infrastructure_and_Telecommunications#/media/File:Gateway-configuration-20180705.jpg

     
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 08/01/2022 04:20 pm
https://www.gao.gov/assets/gao-22-105212.pdf

Quote from: Page 51
As of February 2022, the co-manifested vehicle is above the Falcon
Heavy launch vehicle’s mass limit. If the mass is too high, it could affect
the vehicle’s ability to reach the correct lunar orbit. The project is taking
steps to reduce mass, including evaluating whether it needs to
potentially off-load some components for initial launch.
co-manifested vehicle = PPE + HALO
I don't understand this quote. Falcon Heavy was never supposed to put PPE+HALO into a lunar orbit in the first place. As I uderstand it, after FH puts PPE+HALO into orbit, PPE is supposed to move PPE+HALO into NRHO, taking about nine months to do so. If PPE+HALO is heavier, PPE will have more work to do. Worst case, PPE will need refuelling, but it is supposed to be designed for this, presumably from Dragon XL as part of GLS.

If PPE+HALO is sufficiently overweight, then the Falcon Heavy might not be able to put it into its target high Earth orbit insertion. The PPE might not have enough fuel to break out of Earth orbit and insert the modules into the NRHO orbit.

Refueling would add complexity (another launch, the refueling vehicle) to the mission, and aside from increasing the cost, would delay it until the refueling vehicle was ready.
The other alternative would be to switch back to the concept of launching PPE and HALO separately and mating them in space. That was part of mpst of the early concepts, I think. The pre-mated, single-launch PPE+HALO is relatively recent. I don't know if two FH launches could put HALO and PPE into NRHO separately, but surely they could be assembled in a high Earth orbit before having PPE take them to NRHO? This would require autonomous or tele-operated assembly, or doing the assembly in an orbit that is reachable by Crew Dragon, which might not be high enough.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 08/01/2022 04:26 pm
I have become very confused (or I have become aware that I am very confused).

The Gateway architecture has changed quite a lot over multiple iterations, so quite a few diagrams or graphics about the layout are obsolete and quite a few older published statements about Gateway are no longer valid.

Is there a definitive current architecture published somewhere? Where?

Is there any sort of coherent description of the evolution of the architecture? Where?
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 08/01/2022 04:36 pm
How will the PPE be refuelled? One of the several pieces that make up ESPRIT is (was?) called a refuelling module, but it appears (appeared?) to be permanently attached to Gateway, and it has an extra dock and other permanent stuff, and no apparent way to maneuver, so it does not appear to be intended to be replaced. The only current GLS (Gateway logistics services) spacecraft is Dragon XL, and I see no mention that it will be carrying PPE fuel. PPE can use Xenon for its electric thrusters and can also(?) use "chemical propulsion(?)" and the ERM has tankage for both.
Title: Re: Gateway Discussion Thread
Post by: Jim on 08/01/2022 05:46 pm
The other alternative would be to switch back to the concept of launching PPE and HALO separately and mating them in space.

Not happening
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 08/01/2022 05:48 pm
How will the PPE be refuelled? One of the several pieces that make up ESPRIT is (was?) called a refuelling module, but it appears (appeared?) to be permanently attached to Gateway, and it has an extra dock and other permanent stuff, and no apparent way to maneuver, so it does not appear to be intended to be replaced. The only current GLS (Gateway logistics services) spacecraft is Dragon XL, and I see no mention that it will be carrying PPE fuel. PPE can use Xenon for its electric thrusters and can also(?) use "chemical propulsion(?)" and the ERM has tankage for both.

ESPIRIT is currently intended to dock to one of the side ports on the HALO module. Its design is doughnut-shaped, with a transfer tunnel in the center and docking ports on both sides, so that logistics vehicles can dock to it and still deliver supplies to the Gateway.

Logistics / resupply vehicles are supposed to be able to transfer more Xenon and bipropellant fuel to the ESPIRIT module, yes. I suppose that a logistics vehicle would technically be able to supply the fuel directly, without ESPIRIT as an intermediate.

Attached document, "JOINT DEVELOPMENT TESTING OF THE INTEGRATED GATEWAY-ESPRIT BIPROPELLANT REFUELLING SYSTEM" with screenshots from it, is from May 2022

Anatoly Zak's render is slightly dated - Roscosmos is no longer providing an airlock - but does show ESPIRIT in the correct position.
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 08/01/2022 05:59 pm
https://www.gao.gov/assets/gao-22-105212.pdf

Quote from: Page 51
As of February 2022, the co-manifested vehicle is above the Falcon
Heavy launch vehicle’s mass limit. If the mass is too high, it could affect
the vehicle’s ability to reach the correct lunar orbit. The project is taking
steps to reduce mass, including evaluating whether it needs to
potentially off-load some components for initial launch.
co-manifested vehicle = PPE + HALO
I don't understand this quote. Falcon Heavy was never supposed to put PPE+HALO into a lunar orbit in the first place. As I uderstand it, after FH puts PPE+HALO into orbit, PPE is supposed to move PPE+HALO into NRHO, taking about nine months to do so. If PPE+HALO is heavier, PPE will have more work to do. Worst case, PPE will need refuelling, but it is supposed to be designed for this, presumably from Dragon XL as part of GLS.

If PPE+HALO is sufficiently overweight, then the Falcon Heavy might not be able to put it into its target high Earth orbit insertion. The PPE might not have enough fuel to break out of Earth orbit and insert the modules into the NRHO orbit.

Refueling would add complexity (another launch, the refueling vehicle) to the mission, and aside from increasing the cost, would delay it until the refueling vehicle was ready.
The other alternative would be to switch back to the concept of launching PPE and HALO separately and mating them in space. That was part of mpst of the early concepts, I think. The pre-mated, single-launch PPE+HALO is relatively recent. I don't know if two FH launches could put HALO and PPE into NRHO separately, but surely they could be assembled in a high Earth orbit before having PPE take them to NRHO? This would require autonomous or tele-operated assembly, or doing the assembly in an orbit that is reachable by Crew Dragon, which might not be high enough.

RCS maneuvering systems, independent solar panels, star trackers for orientation, etc. have already been removed from the HALO design. It is not capable of free flight.

Reminder that production and assembly for both modules is already well underway. Going back to a separate launch for each one would involve a pretty hard reset of the entire Gateway program, with significant redesign and rework required. Gateway would be delayed for a couple of years at least.
Title: Re: Gateway Discussion Thread
Post by: whitelancer64 on 08/01/2022 06:05 pm
I have become very confused (or I have become aware that I am very confused).

The Gateway architecture has changed quite a lot over multiple iterations, so quite a few diagrams or graphics about the layout are obsolete and quite a few older published statements about Gateway are no longer valid.

Is there a definitive current architecture published somewhere? Where?

Is there any sort of coherent description of the evolution of the architecture? Where?

The image on this tweet is also a good visual for the currently planned design.
https://twitter.com/NASA_Gateway/status/1516824035140677634
Title: Re: Gateway Discussion Thread
Post by: butters on 08/01/2022 06:34 pm
Oh I see. ESPIRIT was previously supposed to be attached to the PPE as the second module of the Gateway. But since the HALO was subsequently co-manifested with the PPE, most of ESPIRIT moved to its current location where the logistics module was supposed to dock to HALO, requiring ESPIRIT to be redesigned in a donut shape and also requiring the HALO to have plumbing running through it for PPE refueling. Meanwhile, ESPIRIT's communications system was added to the PPE+HALO party by virtue of being necessary for the Minimal Gateway.

It all makes sense. For some definition of sense-making that comes from following the human exploration saga for long enough. The current design is weird because the original design would have taken almost literally forever to assemble as envisioned for extremely familiar reasons. It's shaped like a donut, transfers propellant through the habitation module, and won't be launched for several years after the PPE, because orange rocket bad.
Title: Re: Gateway Discussion Thread
Post by: DanClemmensen on 08/01/2022 06:55 pm
https://www.gao.gov/assets/gao-22-105212.pdf

Quote from: Page 51
As of February 2022, the co-manifested vehicle is above the Falcon
Heavy launch vehicle’s mass limit. If the mass is too high, it could affect
the vehicle’s ability to reach the correct lunar orbit. The project is taking
steps to reduce mass, including evaluating whether it needs to
potentially off-load some components for initial launch.
co-manifested vehicle = PPE + HALO
I don't understand this quote. Falcon Heavy was never supposed to put PPE+HALO into a lunar orbit in the first place. As I uderstand it, after FH puts PPE+HALO into orbit, PPE is supposed to move PPE+HALO into NRHO, taking about nine months to do so. If PPE+HALO is heavier, PPE will have more work to do. Worst case, PPE will need refuelling, but it is supposed to be designed for this, presumably from Dragon XL as part of GLS.

If PPE+HALO is sufficiently overweight, then the Falcon Heavy might not be able to put it into its target high Earth orbit insertion. The PPE might not have enough fuel to break out of Earth orbit and insert the modules into the NRHO orbit.

Refueling would add complexity (another launch, the refueling vehicle) to the mission, and aside from increasing the cost, would delay it until the refueling vehicle was ready.
The other alternative would be to switch back to the concept of launching PPE and HALO separately and mating them in space. That was part of mpst of the early concepts, I think. The pre-mated, single-launch PPE+HALO is relatively recent. I don't know if two FH launches could put HALO and PPE into NRHO separately, but surely they could be assembled in a high Earth orbit before having PPE take them to NRHO? This would require autonomous or tele-operated assembly, or doing the assembly in an orbit that is reachable by Crew Dragon, which might not be high enough.

RCS maneuvering systems, independent solar panels, star trackers for orientation, etc. have already been removed from the HALO design. It is not capable of free flight.

Reminder that production and assembly for both modules is already well underway. Going back to a separate launch for each one would involve a pretty hard reset of the entire Gateway program, with significant redesign and rework required. Gateway would be delayed for a couple of years at least.
OK, PPE and HALO are no longer a pair of "co-manifested" payloads. They are now basically a single spacecraft that has evolved from an earlier pair of modules.
Title: Re: Gateway Discussion Thread
Post by: Zed_Noir on 08/30/2022 02:55 pm
cross-posted from the "Big Falcon Hopper onwards - Starship Hopper, Starship, Super Heavy Render thread"
https://youtu.be/vVLK0tgLHro

Quote
NASA's Artemis Gateway with SpaceX's Human Landing System (HLS)
30 Aug 2022

Gateway is a critical part of NASA’s deep space exploration plans, along with the Space Launch System (SLS) rocket, Orion spacecraft and human landing system. As astronauts prepare for missions to the lunar surface, they will need deliveries of critical pressurized and unpressurized cargo, science experience and supplies, such as sample collection materials and other items. In March 2020, NASA awarded SpaceX as the first U.S. commercial provider under the Gateway Logistics Services contract to deliver cargo and other supplies to the lunar outpost on the SpaceX Dragon XL logistics module.

The agency’s powerful Space Launch System rocket will launch four astronauts aboard the Orion spacecraft for their multi-day journey to lunar orbit. There, two crew members will transfer to the SpaceX human landing system (HLS) for the final leg of their journey to the surface of the Moon. After approximately a week exploring the surface, they will board the lander for their short trip back to orbit where they will return to Orion and their colleagues before heading back to Earth.

NASA’s Artemis program will land astronauts on the Moon and reveal new knowledge about the Moon, Earth and our origins in the solar system. At the Moon, NASA and its partners will gain the experience necessary to mount a historic human mission to Mars.

Gateway model credit: Andreas Engevold
andreas93609.artstation.com

This new Hazegreyart you-tube video clip illustrated the size disparity of the Gateway and Orion when even comparing to the Dragon XL, never mind the Moonship.

Title: Re: Gateway Discussion Thread
Post by: sdsds on 09/11/2022 03:20 am
Regarding Gateway:
Quote from: GAO
The project held its preliminary design review in May 2021. [...] The project office plans to hold its
critical design review in August 2022.

Is it known if the CDR actually took place in August?
Title: Re: Gateway Discussion Thread
Post by: lrk on 09/14/2022 09:14 pm
Regarding Gateway:
Quote from: GAO
The project held its preliminary design review in May 2021. [...] The project office plans to hold its
critical design review in August 2022.

Is it known if the CDR actually took place in August?

Yes it did.