totm dec 2023 Artemis Discussion Thread

[kerbiloid]

Imho just any lunar program gets reasonable only if there is a 200-t-capable fully reusable LV, to keep the progress continuing.
Otherwise it's just another set of launches to nowhere.

(Unless the real aim of the lunar program is a set of high-orbit combat stations with Orion as a supply ship which can deorbit at 11 km/s.
Though, in this case they anyway need a 60-t-capable reusable rocket)

Edited October 18, 2019 by kerbiloid

[sh1pman]

4 hours ago, kerbiloid said:

200-t-capable fully reusable LV

200t to the Moon or to LEO?

[kerbiloid]

3 minutes ago, sh1pman said:

200t to the Moon or to LEO?

i mean LEO, but feel free to provide the Moon.

[sh1pman]

Just now, kerbiloid said:

i mean LEO, but feel free to provide the Moon.

With fully reusable AND refuel-able LV 200t to LEO equals to 200t to anywhere. 

200t seems like a lot, maybe 100-150t is enough? 

[kerbiloid]

32 minutes ago, sh1pman said:

200t seems like a lot, maybe 100-150t is enough?

I orient towards good old classics, direct ascent Apollo/LK-700, the 80 t lunar base module from LK-700 project, and an engineering machine on tank-like chassis to be landed.
As I can calc, it requires 180..200 t in LEO.
(Of course, I don't insist on the direct ascent, but other parts look like this)

The 80 t look reasonable, like a lighter Skylab on a platform or a pair of Almazes (hab and lab) with additional stuff on same platform.
So, you can just land the base with no acrobatics with many modules, then make a ground wall around it with the bulldozer, then dig and drill with the same bulldozer to open deeper layers of the ground.
3 expeditions to the same site, then it's abandoned. (The bulldozer, too.)
Several such temporary sites, then a permanent base next to the nutation zone near the South Pole, to be used for a couple of decades and maybe later.

Edited October 18, 2019 by kerbiloid

[tater]

BTW, I heard an interview where they said that the real spacesuits will just be white, not the kooky color pattern.

[kerbiloid]

Spoiler

5 hours ago, tater said:

BTW, I heard an interview where they said that the real spacesuits will just be white, not the kooky color pattern.

They will be brown.

Spoiler

No place to wash them from regolith.

 

 

[wumpus]

On 10/18/2019 at 6:58 AM, kerbiloid said:

i mean LEO, but feel free to provide the Moon.

LEO used to be halfway to anywhere (RAH).  If you are willing to wait until ion-powered spacecraft maneuver fuel-depots into position it is 90%+ of the way anywhere.

[kerbiloid]

5 minutes ago, wumpus said:

LEO used to be halfway to anywhere (RAH).  If you are willing to wait until ion-powered spacecraft maneuver fuel-depots into position it is 90%+ of the way anywhere.

I don't think that ions are a proper tool for lunar program.
They are either for small things, or for very big but rare.
The lunar program requires medium-sized things and often.

Edited October 20, 2019 by kerbiloid

[wumpus]

1 minute ago, kerbiloid said:

I don't think that ions are a proper tool for lunar program.
They are either for small things, or for very big but rare.
The lunar program requires medium-sized things and often.

You still need ~3000m/s delta-v from LEO to the Moon.  You can either boost mostly rocket up from sea level or boost mostly cargo + ion power and wait much longer.  And the same is true for Mars.  I'd assume you would lift the trans-Mars habitat into Lunar orbit and then use gravity tricks to move it into a more elliptical orbit.  Then send the crew and the final 1000m/s boost to Mars.

If you want to get to the Moon in 2025 (Congress appears to have scuttled 2024), forget the whole idea of ions.  But if you want to do it with less launches and cost, it should definitely be on the table.

[jinnantonix]

8 hours ago, wumpus said:

You still need ~3000m/s delta-v from LEO to the Moon.  You can either boost mostly rocket up from sea level or boost mostly cargo + ion power and wait much longer.  And the same is true for Mars.  I'd assume you would lift the trans-Mars habitat into Lunar orbit and then use gravity tricks to move it into a more elliptical orbit.  Then send the crew and the final 1000m/s boost to Mars.

If you want to get to the Moon in 2025 (Congress appears to have scuttled 2024), forget the whole idea of ions.  But if you want to do it with less launches and cost, it should definitely be on the table.

We can all see that commercial rockets like BFR and New Glenn will be launching big payloads to LEO with re-usable, natural gas powered rockets within a decade, and these will dramatically decrease the cost of payload to orbit.  But how suitable are these craft for humans, or for deep space operations?  How efficient are they for providing TLI or TMI where there is restricted re-usability due to the limitations of cryogenic fuels?

In my opinion for operations beyond LEO we would best use NTER - Nuclear Thermal-Electric Rockets as tugs.  These would be robotically controlled re-usable craft used to provide the dV to transit cargo from LEO to lunar orbit, as well as transporting to locations in heliocentric or Martian orbit.  With ISP ~550-800, 2 years operation between nuclear refueling (at the ISS?) and enough thrust to launch from the lunar surface, these are the ideal compromise between time and efficiency.  Ideally the craft would be refueled with mass propellant - hydrogen or methane for launch or (storeable) ammonia for long term missions, with the propellant manufactured on the lunar surface.  Of course, this option all depends on the viability of fuel manufacture at the lunar south pole ... which is what Artemis is all about.  We don't get to do any of this funky stuff if there is no raw material for fuels, or ISRU cannot be setup cost effectively.

[tater]

I don't see NTRs as lander engines, but the old NASA concept of the Space Transportation System could still use them.

Shuttle, Nuclear Ferry (LEO<-->cislunar), and tug. In this case the cheap access to LEO would be reusable TSTO vehicles, and the ferry would be an NTR craft, refilled by the TSTO crafts. The Tug could also function as LLO to the surface and back, since it only does landing and ascent, the Ferry does the transport to and from lunar orbit.

Edited October 21, 2019 by tater

[jinnantonix]

12 minutes ago, tater said:

I don't see NTRs as lander engines, but the old NASA concept of the Space Transportation System could still use them.

Shuttle, Nuclear Ferry (LEO<-->cislunar), and tug. In this case the cheap access to LEO would be reusable TSTO vehicles, and the ferry would be an NTR craft, refilled by the TSTO crafts. The Tug could also function as LLL to the surface and back, since it only does landing and ascent, the Ferry does the transport to and from lunar orbit.

My testing shows from a performance perspective NTER is quite capable of lunar descent and ascent.  Ultimately a means of autonomously ferrying ore or fuel or propellant to LLO is needed, I just don't see the need for designing and building multiple ship propulsion systems, when a single NTER based system does it all at the best possible efficiency levels.  A pair of tugs can ferry raw materials/propellant from the lunar mining facility to the LOP-G ESPRIT module, and another pair can be fueled at LOP-G ESPRIT module for Earth-Lunar transit operations, while in the longer term future another pair could be deployed to conduct deep space transit operations.

Human rated vehicles like Orion or Dragon v2 would still be needed, not the least for Earth launch and re-entry.  I would envisage another type of craft would be needed for human rated long term (beyond 3 weeks) deep space operations, that would incorporate spin gravity and radiation protection.  This craft would be ferried by the NTER deep space tugs.

[tater]

Yeah, NTRs can certainly work in that application, I just am not sure of wanting crew walking around near the engines. That's the nice thing about keeping them in space. They can even do some of the descent burn, then release the lander, and head back to a more suitable orbit.

[jinnantonix]

21 minutes ago, tater said:

Yeah, NTRs can certainly work in that application, I just am not sure of wanting crew walking around near the engines. That's the nice thing about keeping them in space. They can even do some of the descent burn, then release the lander, and head back to a more suitable orbit.

I am sure having propellant tanks between the engines and humans should be enough protection.  Can't see radiation from these engines being a significant hazard, compared to the risks and environmental hazards of being in deep space.  Not sure why humans would be "walking around the engines", I would envisage everything to be autonomous, including the lunar mining operation.

 

Edited October 21, 2019 by jinnantonix

[Ultimate Steve]

10 minutes ago, jinnantonix said:

I am sure having propellant tanks between the engines and humans should be enough protection.  Can't see radiation from these engines being a significant hazard, compared to the risks and environmental hazards of being in deep space.  Not sure why humans would be "walking around the engines", I would envisage everything to be autonomous, including the lunar mining operation.

 

You are protected by the fuel tank until you climb the ladder down to the surface. In a traditional design, this would mean walking around the engines.

[jinnantonix]

1 hour ago, Ultimate Steve said:

You are protected by the fuel tank until you climb the ladder down to the surface. In a traditional design, this would mean walking around the engines.

There is no intention in my mind of these craft being used to land humans on the lunar surface, at least not in the short term.  If you look up the thread, I see the immediate requirement for a crewed lunar lander architecture being based around more familiar human rated systems, and in particular a fully expendable hypergolic fueled tug, and a re-usable variant of the Orion pressure vessel with hypergolic thruster engines.  This provides the initial landing systems to prove lunar mining and ISRU.  Once that is proved, the NTERs provide an automated service for cargo delivery, or perhaps deep space ferrying.  Any future human landings on the moons surface would continue to use the already proven human rated systems, although likely the landers will be launched fully integrated and fueled into LLO by BFG or New Glenn cargo LVs and ferried to the LOP-G using an NTER tug.

 

Edited October 21, 2019 by jinnantonix

[tater]

Yeah, but this is an Artemis thread. Notional human landers based on the Orion pressure vessel? Sure, plausible.

NTP landers for mining operations? LOL. As much as I'd like to see this... For Artemis? Sorry, no. They'll be lucky to get a flags and footprints mission by 2028 (not that I wouldn't want the NTP people at Marshall to get tons of money dumped in their laps for actual flight tests, that's exactly what NASA should be doing... but their masters give them money for other things, instead).

[jinnantonix]

20 minutes ago, tater said:

Yeah, but this is an Artemis thread.

@tater I was responding to the discussion about 200 ton re-usable landers and ion engines, which has nothing to do with Artemis, and is something we would not see until well after the timeline for Artemis has expired.  That is unless you believe that Electric Jesus is completing preparations for using Starship to take paying passengers to Mars and back.

Quote

Notional human landers based on the Orion pressure vessel? Sure, plausible.

LockMart certainly thinks so, but with a bit of thought (which LockMart has not yet invested in), it might be possible to actually launch a lunar lander cost effectively with commercial LVs.

Quote

NTP landers for mining operations? LOL. As much as I'd like to see this... For Artemis? Sorry, no. They'll be lucky to get a flags and footprints mission by 2028 (not that I wouldn't want the NTP people at Marshall to get tons of money dumped in their laps for actual flight tests, that's exactly what NASA should be doing... but their masters give them money for other things, instead).

The Artemis Program doesn't just achieve a crewed landing, it extends to multiple landings, and across the entire construction of the LOP-G and science gathering needed to deliver on Artemis 8 a "Lunar Surface Asset", which I take to mean an ISRU facility.  There isn't much use in doing Artemis if there is no way to effectively lift the proceeds of all this effort from the lunar surface, to somewhere it might be used productively.  Expect that as Artemis proceeds, assuming it proves ISRU feasible, there will be more requests for research into NTER craft and ISRU facility design and build, and no reason why this would not be contracted out to the private sector.

 

Edited October 21, 2019 by jinnantonix

[tater]

1 hour ago, jinnantonix said:

 I was responding to the discussion about 200 ton re-usable landers and ion engines, which has nothing to do with Artemis, and is something we would not see until well after the timeline for Artemis has expired.  That is unless you believe that Electric Jesus is completing preparations for using Starship to take paying passengers to Mars and back.

The 200t (ish) reusable lander is a thing, possibly, didn't see anything about it being ion driven, though if you are sending empty stuff for habs, I suppose that might do if you have nothing but time, least to get it close. I've never been a Mars fan, I'm more in the Bezos camp regarding resource exploitation. Mars seems more trouble than it is worth as a place to live, and I'll believe Mars colonization when I see it, not before.

(Just out of curiosity, is it even possible to watch more than about 10 seconds of that video? I certainly couldn't. I've spent time in a few Teslas by now and they are really nice cars, and remarkably fast (feel like they'd leave our 335xi standing). Anyway, I liked them enough I'm seriously considering buying one. Dunno what some random codger's complaints are (wasn't entertaining enough to watch at all), and I don't particularly care. If he starts making something I'd rather buy I'm open to checking it out, and maybe I'd watch one of his vids (he's not terribly entertaining on YT, hope that's not his day job)

1 hour ago, jinnantonix said:

Expect that as Artemis proceeds, assuming it proves ISRU feasible, there will be more requests for research into NTER craft and ISRU facility design and build, and no reason why this would not be contracted out to the private sector.

Yeah, hopefully we see something actually happen with that. Maybe if they sign on enough foreign programs they can push it past any changes in management in the next couple years. I tend to think the first crew landing is nothing like 2024 (partially technical reasons and tight schedule, partially politics), which pushes any subsequent missions even farther out.

Edited October 21, 2019 by tater

[jinnantonix]

6 minutes ago, tater said:

I tend to think the first crew landing is nothing like 2024 (partially technical reasons and tight schedule, partially politics), which pushes any subsequent missions even farther out.

Tend to agree, but depending on the approved lunar lander design, I think it is feasible to send a crew to LOP-G and to land a robotically controlled prototype.  The lander could crash, or not successfully return to LOP-G, but as long as Orion delivers the crew safely on the round trip, the Artemis 3 mission would be considered success.  Artemis plans up to 5 landings to Artemis 8, and if there are a few uncrewed tests before the first footsteps on the moon, that still fits with the program objectives.

[tater]

I'd think that an all up test of any lander (uncrewed) would be pretty much required.

[sevenperforce]

On 10/16/2019 at 8:05 PM, jinnantonix said:

Here is the suggested lunar lander model, including 3 inline Super DRACO engines, Orion pressure vessel with ladder and RTG and additional DRACO thrusters for improved acceleration and redundancy.

Ascent vehicle.  The Orion pressure vessel upper stage is re-usable and is able to transit from LLO to NRHO using only DRACO thrusters.  The upper stage has a wet mass of 4.6 tons (excluding crew and logistics) so could be launched on a Falcon 9 or Vulcan, and transit autonomously to the LOP-G utilising its DRACO thrusters.  Since it is re-usable, only one launch is required across the Artemis program.

This is the ideal, I agree. Single launch, replaceable if it wears out but otherwise reusable. 

On 10/16/2019 at 8:05 PM, jinnantonix said:

Ascent vehicle launching from the lunar surface after separation from the descent stage.

Lander stage 2 is full expendable.  Comprises:

• 4 x drop tanks which are jettisoned after the LOP-G to LLO transit
• 4 x fuel tanks with lander legs for the descent from LLO to lunar surface
• 1 x Ascent vehicle tank with 3 x SuperDRACO engines  

This craft has a wet mass of 31 tons but may be launched (partially fueled) comanifested with the crewed Orion on the SLS, docking directly with the Ascent Vehicle upper stage at the LOP-G

There are a lot of elements to optimize for, not all of which are straightforward or even compatible. Ingress and egress is the obvious one. Do you depressurize the entire cabin or use an airlock? Is the airlock hard or expandable, reusable or jettisoned? Do you use ladders or do you leverage the structure to get down to the surface directly?

Cargo delivery and access is another critical question. If you can fold up a rover and slap it on the side of the descent module, like they did in Apollo, then good for you. But if you can drop cargo from directly underneath, like the Starship concepts, that's even better. And to top it all off, you want a lander stack that is modular (so you can build on it), assembleable on orbit, capable of jettisoning unnecessary mass as fast as possible, AND has the lowest possible complexity.

On 10/16/2019 at 8:05 PM, jinnantonix said:

Modified Cygnus type refueller able to transit autonomously to the LOP-G, dock and utilise the ESPRIT module to deliver up to 10 tons of payload, including logistics and hypergolic propellant.  Two refuelling / reprovisioning missions using a Falcon Heavy LV  is required per lunar landing mission.

It would be far easier, I think, to replace drop tanks manually using a Canadarm than to master multi-tonne hypergolic propellant transfer. More mass-efficient, too.

 

1 hour ago, tater said:

I'd think that an all up test of any lander (uncrewed) would be pretty much required.

If they didn't want to do an all-up test, they could do a rerun of Apollo 10, but with a descent stage carrying side-slung or under-slung cargo that would land autonomously while the crew vehicle returned. That way you don't waste the launch.

[tater]

Interestingly, this LockMart mockup can't be based on Orion at all (looks like they used Altair mockup parts).

 

Edited October 21, 2019 by tater

[sevenperforce]

1 hour ago, tater said:

Interestingly, this LockMart mockup can't be based on Orion at all (looks like they used Altair mockup parts).

 

I wanna see more about that first one. Are those radiators on the front?