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According to the Gateway Update Thread, construction on PPE and HALO is fairly far along?
https://forum.nasaspaceflight.com/index.php?topic=51452.msg2541132#msg2541132
True. But if the integrated vehicle stack is overweight. They will need to reduce the mass somehow. Likely with re-working the internal arrangements and offloading mass to the Dragon XL logistics vehicle and/or the SpaceX HLS lander.
I recall that the xenon fuel is refillable. So off loading propellant may also be an option. I believe it was a sizeable load.
PPE has both electrical and chemical thrusters, and both the Xenon and the chemical fuel are refillable PPE was supposed to launch with about 2500 kg of fuel. However, it cannot be refilled until someone builds a spacecraft to carry that fuel. Unfortunately, the various redesigns have shifted the refilling concept around quite a bit, so it's hard to know what the current status is unless you are an insider (not me).
Apparently, in an early design the PPE was refuelled directly from a refueler. Then PPE was supposed to connect permanently and directly to ESPRIT, and the refueller would connect to ESPRIT. Now, PPE connects to HALO and ESPRIT connects to HALO, and the refueller connects to ESPRIT, and all of this happens in the far future.
To get past this mess in the short(?!) term, NASA could contract for a refueller that can connect directly to HALO using the port that will be used for ESPRIT. They could then launch PPE+HALO (almost) dry, and refuel in LEO, and then refuel again in NRHO.
I do not know enough about the technology, processes, or politics to have a informed opinion, but my guess is that there is no possible way to get this done in time to be useful. It looks like the ESPRIT team would be best suited for this, but ESPRIT is an ESA project.
There is no sepearate refueling port on PPE now - it just goes through HALO. The stack is being launched to a sort of GTO, not LEO. This would make refueling difficult, and also minimizing the amount of time spent in the Van Allen belts is a major concern so hanging out to wait for re-fueling would not be ideal. Off-loading some fuel and refueling in NRHO sooner is a possibility, though.
It's best to think of PPE+HALO as basically one spacecraft at this point, with a number of ...interesting design choices carried over from being two spacecraft originally. In retrospect, it would have been much cheaper (and more mass efficient) to start over and design an integrated spacecraft from the ground up. But NASA has a strong aversion to paying termination costs - as seen with the Ares upper stage contract being modified to become the SLS core stage, instead of re-competing. And since PPE/HALO were firm fixed price contracts originally, there has been a lot of time and money wasted just on negotiating contract modifications due to changing requirements.
Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:
https://en.wikipedia.org/wiki/Vandenberg_Space_Launch_Complex_6#SpaceX_(from_2023)
"SpaceX expects to begin Falcon 9 launches from SLC-6 in 2025 and Falcon Heavy launches in 2026".
that doesn't seem an issue ppe/halo launch will slip to 2028-30 due to Artemis delays and no demo modules construction even. Issue is why can't the vandy facilities handle? This saves SpaceX money for additional vif tower. Also tell the delta v needed to reach near equatorial earth orbit of Moon from a Polar or 52 inclination orbit from vandy.
Alternatively, lay down pad 39a rails till nasa's vab near sls vab that is leased to SpaceX for Starship. And roll Transporter erector vertically that I doubt it can move vertically as it rolls horizontally
PPE/HALO is planned to integrate horizontally with Falcon Heavy. The processing facilities Jim is referring to are for payload processing - the complete vehicle is too big to transport, so the various pieces are being assembled at the cape.
And launching from VAFB would further cut into the already-tight performance margins, due to the higher inclination.
Surely they have already done the simplest mass reductions? The most obvious reduction (as seen from the outside by this uneducated observer) is to replace the PPE-to-HALO docking systems on both spacecraft with a fixed connection.
There is no docking systems. The decision to fly HALO PPE together was done before PDR of either system.
there must be Ida for further add no modules.
Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:
https://en.wikipedia.org/wiki/Vandenberg_Space_Launch_Complex_6#SpaceX_(from_2023)
"SpaceX expects to begin Falcon 9 launches from SLC-6 in 2025 and Falcon Heavy launches in 2026".
that doesn't seem an issue ppe/halo launch will slip to 2028-30 due to Artemis delays and no demo modules construction even. Issue is why can't the vandy facilities handle? This saves SpaceX money for additional vif tower. Also tell the delta v needed to reach near equatorial earth orbit of Moon from a Polar or 52 inclination orbit from vandy.
Alternatively, lay down pad 39a rails till nasa's vab near sls vab that is leased to SpaceX for Starship. And roll Transporter erector vertically that I doubt it can move vertically as it rolls horizontally
PPE/HALO is planned to integrate horizontally with Falcon Heavy. The processing facilities Jim is referring to are for payload processing - the complete vehicle is too big to transport, so the various pieces are being assembled at the cape.
And launching from VAFB would further cut into the already-tight performance margins, due to the higher inclination.
I mean what ppe/halo can be integrated horizontally. Aiiiiah wait a minute
Ok just remembered that nauka type jumbo module was integrated horizontally. I assumed falsely that long fairing means you need VIF
Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:
https://en.wikipedia.org/wiki/Vandenberg_Space_Launch_Complex_6#SpaceX_(from_2023)
"SpaceX expects to begin Falcon 9 launches from SLC-6 in 2025 and Falcon Heavy launches in 2026".
that doesn't seem an issue ppe/halo launch will slip to 2028-30 due to Artemis delays and no demo modules construction even. Issue is why can't the vandy facilities handle? This saves SpaceX money for additional vif tower. Also tell the delta v needed to reach near equatorial earth orbit of Moon from a Polar or 52 inclination orbit from vandy.
Alternatively, lay down pad 39a rails till nasa's vab near sls vab that is leased to SpaceX for Starship. And roll Transporter erector vertically that I doubt it can move vertically as it rolls horizontally
PPE/HALO is planned to integrate horizontally with Falcon Heavy. The processing facilities Jim is referring to are for payload processing - the complete vehicle is too big to transport, so the various pieces are being assembled at the cape.
And launching from VAFB would further cut into the already-tight performance margins, due to the higher inclination.
I mean what ppe/halo can be integrated horizontally. Aiiiiah wait a minute
Ok just remembered that nauka type jumbo module was integrated horizontally. I assumed falsely that long fairing means you need VIF
nauka type jumbo module was one piece.
Falcon payloads are vertically encapsulated.
PPE is a standard Maxar spacecraft bus. It is not design to be supported on its side. When horizontal, it is cantilevered from its base. The same area that is mated to HALO
IIRC it was at the January 9 media briefing (where the Artemis-2 and -3 launch schedule slips were announce) that some NASA official indicated an update would be coming soon on the expected PPE+HALO launch date. Has that update been made public?
The President's budget request shows the launch in 2026
The President's budget request shows the launch in 2026
In
Fiscal Year 2026. So no change from the latest schedules.
The President's budget request shows the launch in 2026
In Fiscal Year 2026. So no change from the latest schedules.
Ah thanks, yes: NET 2025 calendar Q4 == NET 2026 fiscal Q1.
The President's budget request shows the launch in 2026
It also mentions a "baseline launch readiness date" of December 2027, on page DEXP-49 and following:
Gateway Initial Capability includes the Power and Propulsion Element (PPE), the Habitation and Logistics Outpost (HALO), the commercial launch vehicle for initial launch, and a portion of Program Mission Execution (PME).
The proposed funding levels sufficiently allow the program to support development of Gateway's Initial Capability as soon as is technically feasible. While the confirmation baseline launch readiness date is December 2027, NASA is re-assessing the Gateway Initial Capability work-to launch date, which currently is targeted for no earlier than (NET) October 2025.
Milestone: Initial Capability LRD
Confirmation Baseline Date: Dec 2027
FY 2025 PB Request: Dec 2027
https://www.nasa.gov/wp-content/uploads/2024/03/nasa-fy-2025-congressional-justification.pdf
In today's NAC HEO meeting they said the FH is expendable, can't remember if they've said so explicitly before.
Launch has to occur No Later Then September 2027 to be able to support the Artemis IV mission in September 2028:
GAO: Assessments of Major Projects
June 2024
[...]
Cost and Schedule Status
[...]
The HALO project is working with its contractor, the PPE project, NASA, and its international partners to update its internal project schedule. Program officials stated the comanifested vehicle needs to launch at least a year before the September 2028 Artemis IV mission to allow time for the vehicle to transit from Earth to the moon and prepare for docking. Therefore, NASA would need to integrate the HALO and the PPE and launch them by September 2027 to support the mission. Program officials said they plan to work to a more aggressive internal launch date than the baseline launch date but have not yet determined this new date.
[...]