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#160 by sdsds on 05 Feb, 2024 05:17
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* Human Lunar Return
* Foundational Exploration
* Sustained Lunar Evolution
* Humans to Mars
Gateway isn't involved in the first of those, only the later ones.
https://www.nasa.gov/wp-content/uploads/2024/01/rev-a-acr23-esdmd-001-m2madd.pdf
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#161 by deltaV on 05 Feb, 2024 06:24
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Discussions of what the Gateway is for would be better in the Gateway thread (https://forum.nasaspaceflight.com/index.php?topic=51878.0).
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#162 by Jim on 06 Feb, 2024 14:54
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Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it. -
#163 by DanClemmensen on 06 Feb, 2024 15:01
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Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
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#164 by sdsds on 06 Feb, 2024 21:00
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In the teleconference that was mainly about Artemis crew mission delays, at around 31m 30s, there was a comment that the schedule for PPE+HALO would be updated.
Had previously planned launch for October 2025. Now under review. "We will be updating that schedule here as well." That was January 9. Should we be expecting an update around February 9, or is that unrealistic?
youtube.com/watch?v=ZJVa0z5kZAk -
#165 by Jim on 06 Feb, 2024 22:17
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Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
Was referring to Vandenberg spacecraft facilities -
#166 by DanClemmensen on 07 Feb, 2024 00:25
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Understood. But SpaceX apparently intends to fullfill its NSSL obligations when launching FH from VFSB by upgrading and using SLC-6, and that will include the pad and some kind of spacecraft facilities. Have they said whether they will modify the existing spacecraft facilities or just abandon them and build new ones?
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
Was referring to Vandenberg spacecraft facilities -
#167 by Chinakpradhan on 07 Feb, 2024 11:25
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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.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
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 -
#168 by Vultur on 08 Feb, 2024 00:25
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that doesn't seem an issue ppe/halo launch will slip to 2028-30 due to Artemis delays and no demo modules construction even.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
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 -
#169 by Zed_Noir on 08 Feb, 2024 13:14
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<snip>
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.
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 -
#170 by wannamoonbase on 08 Feb, 2024 15:15
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<snip>
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.
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
I recall that the xenon fuel is refillable. So off loading propellant may also be an option. I believe it was a sizeable load. -
#171 by DanClemmensen on 08 Feb, 2024 15:18
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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. That particular docking connection is one of the most complicated on Gateway. True it has no crew tunnel, but it does support heavy electrical, Xenon, and propellant for the PPE chemical thrusters.<snip>
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.
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 -
#172 by DanClemmensen on 08 Feb, 2024 15:39
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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).<snip>
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.
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
I recall that the xenon fuel is refillable. So off loading propellant may also be an option. I believe it was a sizeable load.
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. -
#173 by Zed_Noir on 08 Feb, 2024 15:55
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Think they already done that.
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. That particular docking connection is one of the most complicated on Gateway. True it has no crew tunnel, but it does support heavy electrical, Xenon, and propellant for the PPE chemical thrusters.<snip>
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.
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
NASA should really consider using the HLS lander as a space tug to get the integrated vehicle stack to a Lunar orbit. Especially since a HLS lander is suppose to be available before the stack is launched.
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#174 by DanClemmensen on 08 Feb, 2024 16:08
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Yep. It would probably require a bunch more tanker flights, but this could be added to the HLS demo. One question: can HLS thrust be throttled down far enough? HLS would probably need to dock to HALO axial, so HALO would need to handle the force of itself plus the fully-fuelled PPE.
Think they already done that.
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. That particular docking connection is one of the most complicated on Gateway. True it has no crew tunnel, but it does support heavy electrical, Xenon, and propellant for the PPE chemical thrusters.<snip>
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.
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
NASA should really consider using the HLS lander as a space tug to get the integrated vehicle stack to a Lunar orbit. Especially since a HLS lander is suppose to be available before the stack is launched.
If I were NASA I would be reluctant to add this complexity to Artemis III or Artemis IV, but it could be added to a lunar cargo flight.
The real irony would occur if they did use Artemis III for this. When Orion showed up they would find HLS already docked to Gateway, because HLS had dock to Gateway in LEO. -
#175 by sdsds on 08 Feb, 2024 18:30
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The motivation for integrating PPE+HALO on the ground was to make the initial Gateway a single-launch mission with no in-space rendezvous required. Using either propellant refilling or a space tug makes the mission multi-launch again. Wouldn't that tacitly admit the prior decision was ... misguided?
Hopefully NASA comes forward soon with a bit more clarity on the mission's current status and plan! -
#176 by Jim on 08 Feb, 2024 21:34
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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. -
#177 by Jim on 08 Feb, 2024 21:37
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Understood. But SpaceX apparently intends to fullfill its NSSL obligations when launching FH from VFSB by upgrading and using SLC-6, and that will include the pad and some kind of spacecraft facilities. Have they said whether they will modify the existing spacecraft facilities or just abandon them and build new ones?
What the NRO does is separate from what NASA does. -
#178 by Jim on 08 Feb, 2024 21:38
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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.
Yep. It will take awhile to convert slc-6. From a ref in Wikipedia:Can SpaceX launch ppe/halo from SLC-6?¿‽¿?
The processing facilities can't handle it.
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".
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
It has nothing to do with pads. -
#179 by Zed_Noir on 08 Feb, 2024 23:42
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<snip>
The acceleration for a stack with an integrated vehicle of the combined PPE & HALO modules plus a fully filled HLS lander with just the Raptor Vacs running at 60% should be within structure limitation of the integrated vehicle stack. Said stack must be able take at least 3Gs during the Falcon Heavy launch.
Yep. It would probably require a bunch more tanker flights, but this could be added to the HLS demo. One question: can HLS thrust be throttled down far enough? HLS would probably need to dock to HALO axial, so HALO would need to handle the force of itself plus the fully-fuelled PPE.
<snip>.
NASA could get a test run of a few orbits with a stack simulator to confirm stress levels. Just add a few more tanker flights.QuoteThe real irony would occur if they did use Artemis III for this. When Orion showed up they would find HLS already docked to Gateway, because HLS had dock to Gateway in LEO.
Probably why NASA might be hesitant to use the HLS lander as a space tug. Since why would the Orion ride to NRHO be needed if you can fly a Crew Dragon to the Integrated Vehicle Stack docked with the HLS lander at the LEO parking orbit. So delays with the SLS and the Orion is not relevant to doing Artemis III or Artemis IV.
