Gateway Minimal Habitation Module

[ncb1397]

Looks like Northrop Grumman is providing the phase 1 Gateway habitation system.

The planned Gateway lunar orbiting platform is critical for staging human exploration
missions to the lunar surface by 2024 as mandated by Vice President Pence, Chairman of
the National Space Council. The Gateway platform will include a pressurized habitation
module with environmental control and life support systems to house astronauts during
lunar missions. To accomplish a lunar landing, astronauts aboard an Orion Spacecraft will
launch toward the moon on an SLS rocket, rendezvous with Gateway (with the MHM) in a
lunar orbit, and descend to the lunar surface via a crewed lander by 2024.
In order to meet NASA’s 2024 human lunar landing deadline, NASA examined the existing
NextSTEP-2 contractors’ concepts for deep space habitation modules. As stated in the
synopsis (80JSC019GTWYHAB), not all contractors currently performing services via the
NextSTEP-2 BAA Appendix A, would be selected to receive an award for this next phase
and additional phases. Each contractor's proposed approach, progress, and capabilities were
reviewed and assessed by NASA for potential use as a MHM. In order to meet the Gateway
Program’s schedule and support the Vice President’s 2024 human lunar landing mandate,
NASA determined it was necessary to continue to work with NGIS for these highly
specialized services. NGIS was the only NextSTEP-2 contractor with a module design and
the production and tooling resources capable of meeting the 2024 deadline.

https://www.fbo.gov/index.php?tab=documents&tabmode=form&subtab=core&tabid=d4e9e11d78e9dd0b8bd05395b3d82c7f

[A_M_Swallow]

Here is a link to the entire document.
"GATEWAY PROGRAM MODULE(S) Continued use of NextSTEP-2 Broad Agency Announcement (BAA) Appendix A"
https://www.fbo.gov/index.php?s=opportunity&mode=form&tab=core&id=36ebf3fc4d57c88b6bd8c94d1806dfb9&_cview=1

[MATTBLAK]

Yay! I'm happy that a Cygnus-based solution is in the works.

[jadebenn]

Exciting to see the groundwork being laid for Gateway!

[woog]

This is a perfect example of sole-sourcing done right. Using a Cygnus derived habitation module solves the tug issue and is overall a very good choice

[Markstark]

Really happy about the quick movement on this. So are the PPE and the Mini-Hab on contract at this point?

Also, since the Phase1 Mini-Hab is launching on a commercial launch vehicle, does the CLV put it on a TLI trajectory and Mini-Hab does the rest (including rendezvous with the PPE in NHRO)?

[envy887]

Really happy about the quick movement on this. So are the PPE and the Mini-Hab on contract at this point?

Also, since the Phase1 Mini-Hab is launching on a commercial launch vehicle, does the CLV put it on a TLI trajectory and Mini-Hab does the rest (including rendezvous with the PPE in NHRO)?

No commercial launchers have the capability to do LOI at the moment. With the Cygnus bus the MHM can do that itself from TLI.

[ncb1397]

Just to get a rough estimate of the maneuverability of the full stack (mini-hab + PPE)

AEPS thrust = .6 Newtons
PPE mass = 9000 kg
Cygnus mass = 3750 kg (uses cargo variant as stand in - this will have some things removed and some things added)

F= ma
F/m = a
a = (.6 + .6 ) / (9000 + 3750) = 0.00009411764 m/s²

acceleration per day = 8.131764096 m/s
acceleration per month = 243.95292288 m/s
acceleration per year = 2968.09389504 m/s

This isn't using the full power of the satellite bus at 1 AU though and isn't using the 4 aux electric thruster's on Maxar's PPE that are proprietary and of unknown thrust. Potentially we are talking about .5 km/s per month(fully fueled) if the 4 aux thrusters equal the thrust of the 2 AEPS thrusters that aren't on the Maxar PPE.

Anyways, it works as a subscale demonstration of a solar electric mars transit vehicle if you can get 1-2 km/s in a couple months time with 30 cubic meters of hab attached. Departing from NRHO, SEP shouldn't extend the 7 month standard trip time to mars by an intolerable amount.

edit: after some research, it appears that the likely auxiliary thruster for the Maxar PPE is the SPT-140. For instance, the renders for the PPE show a similar configuration to the dual thruster assembly on a document describing the SPT-140(page 7, https://iepc2017.org/sites/default/files/speaker-papers/iepc_2017_ssl_electric_propulsion.pdf). This is a 4.5 kw thruster with a peak thrust of .28 Newtons. Total thrust would be 1.12 Newtons, roughly replacing the thrust of 2 AEPS thrusters.

[whitelancer64]

Does a "minimal" hab mean we will see a "full" hab on the Gateway later? Kinda wanted to see an expandable module on it (Bigelow or Sierra Nevada).

[b0objunior]

Does a "minimal" hab mean we will see a "full" hab on the Gateway later? Kinda wanted to see an expandable module on it (Bigelow or Sierra Nevada).

As I understand it, this is suppose to be the first module. If they need more space, a bigger module could be added to the gateway.

[rcoppola]

Does the Canada Arm-2 need to be ready for 2023-4 on the Gateway? Or will Orion and Lander be capable of autonomous Docking to the Hab module? I'm assuming they'll be using the IDA?

[whitelancer64]

Does the Canada Arm-2 need to be ready for 2023-4 on the Gateway? Or will Orion and Lander be capable of autonomous Docking to the Hab module? I'm assuming they'll be using the IDA?

I am not sure if Canadarm 3 would be required for grabbing the lander, but at the very least it would probably be a nice-to-have on station to allow for Gateway resupply. The Canadian space agency did say a couple of months ago that they were looking into accelerating the schedule for the built for Canadarm 3 so it would be ready by 2024.

[A_M_Swallow]

Does NASA intend to use the optional enhancement to the International Docking Standard System (IDSS) allowing transfer of water, fuel and lox?

The importance of the question is that the mini-hab will need to have the connecting pipes installed before launch. This high level decision on in-flight refuelling needs taking within weeks before say the end of August 2019.

This is a high level architecture decision because it effects the design of the landers, PPE, MHM, other Gateway modules and resupply vehicles.

[TrevorMonty]

Besides fact habitat is based on operational vehicle another winning feature  is its smaller diameter. I'd assumed 3m dia would've been minus with reduced internal room compared to competition's larger 4.5m. Turns out they can use extra exterior room to fit equirement, payloads and most importantly another docking port while fitting in standard 5.4m fairing.
No information on ECLSS but using Orions would make sense and reduce mission's spares requirements. I'd hope NASA learnt few lessons from Apollo 13.

NGIS had big head start over competition as more precisely former Orbital has been playing around with ideas to use Cygnus as habitat for years. They could use the same vehicle as basis of small LEO spacestation. Unlike competitors NASA will have paid for all development costs and production facilities would be in place.


Existing LV Fairing Accommodation
In order to meet the 2024 deadline, NASA must use existing commercial launch vehicles to
transport a MHM to lunar orbit for integration into Gateway in time to support the Vice
President’s mandate. Through the existing manufacturing capability previously described,
NGIS has tooling and manufacturability for production of a module with a diameter that can
be uniquely accommodated by existing Commercial Launch Vehicle fairings, while still
supporting radial docking or externally-mounted hardware. While other common module
diameter sizes could potentially be fabricated with already built tooling, those larger
diameters would not accommodate radial docking ports as required.

Additionally, the smaller diameter of the NGIS module enables other externally mounted
capabilities, including batteries, communication antennae, and payloads to be incorporated
upon launch and available for the initial mission. These capabilities uniquely establish a
minimum risk development posture for supplying the initial docking and habitable transfer
capability necessary to support lunar operations in 2024.

[Eric Hedman]

I wonder if the intent is to replace the mini-habitat some time after the first Moon landing.  If it has radial docking ports I would assume it has something on the nose to dock to the PPE.  Wouldn't the aft end have the engines for Halo orbit insertion and not be practical to dock additional modules there?  A bigger diameter replacement habitat ready when some launcher (SS,New Glenn,Vulcan/ACES) has a stage that can do the orbit insertion burn would have more usable space and docking ports at both ends in addition to radial ports might not force them to work out all the details immediately for which docking standard they want to use in the long run.

[brickmack]

No, it has docking ports on both ends. Theres 2 main engines instead of 1, and the propellant tanks/structures in the SM are moved to make room for a docking tunnel, making the SM wider and non-cylindrical. Radial ports are still an option, to be traded against cost/mass/external cargo, but most likely it will have 2 of those

[yg1968]

See slides 6, 9 and 24 for a general idea of what the Minimal Habitat might look like (it's the module attached to the PPE in slides 6 and 9; incidentally, I believe that it would be smaller than the prototype on slide 24):
https://www.nasa.gov/sites/default/files/atoms/files/20190528-nac-heoc-smith-v5b.pdf

See also this article from a couple of months ago:
https://www.nasaspaceflight.com/2019/05/ngis-nasa-test-cygnus-derived-lunar-gateway-habitat/

[jadebenn]

Really happy about the quick movement on this. So are the PPE and the Mini-Hab on contract at this point?

One of the recent articles clarified this. Apparently, they are not officially on-contract yet, but unless they seriously screw-up negotiations, they will be very soon.

Also, congrats OP! As far as I can tell, you publicized this before anyone else on the internet did.

[JohnFornaro]

Generally speaking, it sounds like one of the key pieces for the lunar return is well underway. 

How about the lander?  Who's building that?

[speedevil]

Generally speaking, it sounds like one of the key pieces for the lunar return is well underway. 

How about the lander?  Who's building that?

See the discussion on The artemis thread.
They've just announced requirements, and the contract is very, very open in its language so as to allow more or less any design.
Almost the only requirements initially are it's gotta dock at gateway and get to the moon and back, possibly in more than one bit.