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Artemis Discussion Thread

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1 minute ago, sh1pman said:

If Boeing for any reason decides to pull out of Artemis at some point, or messes up the lander so badly it can’t be used, the whole program will end. There won’t be backups like in Commercial Crew or “buy seats from Roscosmos”-option.

They can't really mess it up. An all-Boeing show means they need to:

1. Build and test EUS.

2. Build and test a lander.

3. Continue to build SLS core stages.

These three tasks are all "cost plus," and as a result, have no time limit. If it takes a decade? Then Boeing earns money for a decade. if it takes 2 decades? they earn money for two decades. See, they are incentivized to finish quickly... oh, wait, I guess they have no reason to ever finish, really.

 

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6 minutes ago, tater said:

If it takes a decade? Then Boeing earns money for a decade. if it takes 2 decades? they earn money for two decade

 

They really have no deadlines? Wow, I wish my job was like that.

“We’re going to pay you until you finish the project, whenever that may happen”

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Just now, sh1pman said:

They really have no deadlines? Wow, I wish my job was like that.

“We’re going to pay you until you finish the project, whenever that may happen”

They have milestones to aim for, but as long as Congress wants them to keep working, they get paid. Since the goal to Congress is not results, the goal is spending... they effectively have no time limit. Also, the more that is spent, the more the "sunk cost fallacy" contributes. "We've spent this much, may as well see it through!"

 

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On 1/29/2020 at 6:26 AM, tater said:

They have milestones to aim for, but as long as Congress wants them to keep working, they get paid. Since the goal to Congress is not results, the goal is spending... they effectively have no time limit. Also, the more that is spent, the more the "sunk cost fallacy" contributes. "We've spent this much, may as well see it through!"

 

Boeing doesn't get paid until they deliver against the milestone.  Yet they will have fixed outgoings for their permanent staff, and requirements for fixed outcomes against their contractors.  So there is actually an incentive to deliver against a timeline, they need to reach the milestone or they run out of cash.

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9 minutes ago, jinnantonix said:

Boeing doesn't get paid until they deliver against the milestone.  Yet they will have fixed outgoings for their permanent staff, and requirements for fixed outcomes against their contractors.  So there is actually an incentive to deliver against a timeline, they need to reach the milestone or they run out of cash.

Idk. I’ve heard so many stories from engineers at NASA about Boeing mucking up the works and almost deliberately increasing the required time and actively trying to delay the project.

Edited by Bill Phil

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1 minute ago, Bill Phil said:

Idk. I’ve heard so many stories from engineers at NASA about Boeing mucking up the works and almost deliberately increasing the required time and actively trying to delay the project.

Sounds like a project manager's nightmare. 

I have seen this happen, where the delivery folk are incentivised to delay, or to sabotage presales activities, so they can sit on their hands and still get paid.  Not saying it is the case here, but it does happen.  

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Any change to the design adds schedule and cost. The difference is that with NASA as the highly involved customer (along with Congress), NASA pays retail for these change orders. If the design changes and it's fixed price, meh, it costs the contractor time and effort, but at their cost, not at a markup of their cost.

This entire "NASA owns it" nonsense in the house bill sounds like it came from Shelby, but it's a different state, and a different party, lol. It's nuts.

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Question about mission profile, and specifically more on Constellation/Pre-gateway:

There is always a requirement to land on the Polar region. May I ask how are the seperate, descent, ascent, and docking operation was supposed to be done, especially under Constellation using EDS?

I am trying to think of a few possibility:

  1. Capture by Moon so that when orbit inserted, the combined craft is high inclination. Stay in that inclination
  2. Insert into a low inclinatrion orbit, then
    1. Lander seperate, then land at pole; ascent at pole, then change orbit back to low inclination
    2. Both craft goes to polar orbit, then do the seperate, land, ascend, and dock in the orbit inclination

Which one is the actual proposal?

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I assume the mission profile was a direct TLI to polar, or a rough TLI on free return, then a midcourse correction to polar. Doing a plane change after LOI is prohibitive.

Constellation had EOR of the MPCV (Orion, launched with Ares I) with the lander stack still attached to the Ares V upper stage. Ares V US was to do TLI, Altair (lander) was to do the LOI burn (and presumably midcourse burns).

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@Jestersage , further to @tater  's comment, Artemis proposes that the Lunar Gateway (LOP-G) will be in Near-Rectilinear Halo Orbit, which is roughly equivalent to an elliptical polar orbit with Pe=2,000km over the north pole and Ap=60,000km over the south pole.  Any en route craft (Orion or Lander) would do a TLI adjusted to pass close over the lunar north pole and dock with the LOP-G when it is about midway to Pe.  The lunar lander undocks,  decelerates to LLO, descends and ascends, then rendezvous and docks with the LOP-G.  The crew then transfer to the Orion to return to Earth. 

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@jinnantonix The House version (like they should have a say :confused: ) says that Gateway is not required, and since they want SLS/NASA ownership, that's the Boeing lander.

On the good side, Gateway is not strictly required. Bad side might be that the 2 best landers are off the table (BO?LockMart and SN/Dynetics).

Regardless, Constellation is still relevant because Artemis inherited Orion, whose SM is a holdover from that program---and hence requires a giant lander that can do LOI, or it requires the Constellation EOR architecture (*cough* Orion on NG, lander on SLS).

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So in the old EDS plan (where EDS send both Altair and Orion to Moon), the Orion will be orbiting moon in a high inclination orbit that is achieved during TLI?

So how much delta-V would be required if a change of longitude is needed?

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11 minutes ago, Jestersage said:

So in the old EDS plan (where EDS send both Altair and Orion to Moon), the Orion will be orbiting moon in a high inclination orbit that is achieved during TLI?

So how much delta-V would be required if a change of longitude is needed?

Doesn't that depend on the orbit itself? The landing site, too?

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I'd assume they'd do polar from TLI, and do a hybrid trajectory like the Apollos did after Apollo 12---the initial TLI burn is just a highly elliptical Earth orbit, short of the Moon, then they do a burn to get to a position for LOI as a midcourse correction. So a free return up to that point, otherwise more burns required (like Apollo 13 had to do).

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People seem to be excited about the Artemis and SLS. They should’ve invited a space nerd or two from this forum to their podcast...

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11 minutes ago, jadebenn said:

@tater House version also directs NASA to investigate making a beefier SM for Orion and reactivate high bay 1 of the VAB to enable dual-launch SLS architectures.

But that's not really what I came here to share today. This is:

Trump’s NASA Budget Will Earmark 12% Boost for Agency in 2021

It costs money to read that, and i'm too young to get a job.

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Just now, Dirkidirk said:

It costs money to read that, and i'm too young to get a job.

I'll summarize: The Trump administration is going to propose a roughly $3B increase to the NASA budget, with the lion's share of that money going to the Human Lander System (HLS) program.

This would bring the NASA budget to a total of $25.6B, which is very high historically.

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Glad to see that this is getting more traction! IMO Orion's underpowered service module is one of the worst and most limiting things about the current architecture.

If this passes that would be a very good thing, as the lander budget would be very good to say the least. I also hope that we don't get that pushback to 2028, as that would invalidate a lot of the current momentum.

I don't want to get too political, but I also don't want the next President to mess with the plans too much. That has happened way too many times and it feels like we are actually on the path to something now.

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1 hour ago, Ultimate Steve said:

Glad to see that this is getting more traction! IMO Orion's underpowered service module is one of the worst and most limiting things about the current architecture.

If this passes that would be a very good thing, as the lander budget would be very good to say the least. I also hope that we don't get that pushback to 2028, as that would invalidate a lot of the current momentum.

You're confusing two different things here. The underpowered service module "fix" is in the House bill, which some people don't like because it de-emphasizes the Moon and the current HLS acquisition strategy for more emphasis on Mars and an SLS-launched traditionally-procured lander.

I would expect the Trump budget request to tie closer to the Senate proposal, which keeps Gateway, keeps commercial HLS, and focuses on the Moon as the first step to Mars.

Though I would like to point out that both houses of Congress propose increases in SLS flight rate. Senate wants a minimum of 1 per year, House wants a minimum of 2 per year. So whether you like it or hate it, it's pretty clear neither of them have any intention to get rid of SLS any time soon.

Edited by jadebenn

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The only reason you need a higher powered service module is for cislunar operations. Mars ops uses Orion as a taxi, in fact the SM could be smaller.

A larger SM means you lose every kg of that in comanifested cargo.

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47 minutes ago, tater said:

A larger SM means you lose every kg of that in comanifested cargo

... but gain a more capable Orion CSM, which has been on the wishlist around here. And since it sounds like SLS will be around for awhile, maybe the planned upgrades will actually happen and it might actually turn into a capable, if expensive, SHLV  

 

 

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1 hour ago, StrandedonEarth said:

... but gain a more capable Orion CSM, which has been on the wishlist around here. And since it sounds like SLS will be around for awhile, maybe the planned upgrades will actually happen and it might actually turn into a capable, if expensive, SHLV  

The dv issue is complex.

SLS was not designed with lunar operations with Orion on top in mind. Apollo had more props because it needed to do LOI for the CSM and the LM. So assume the better SM (CSM+). That Apollo profile is impossible for Orion, because you’d have to do EOR with the lander, and you’d have to also have a TLI stage that could push CSM+ with the lander on top to TLI. That’s got to exceed the TLI throw of EUS.

So what can CSM+ do? SLS direct to TLI? CSM+ does LOI and meets lander. Lander sent by ? . That could work, but we’re back to a distributed launch architecture. Once that’s on the table, why not dump SLS? 
 

IVF on EUS could probably do the LOI burn, then you can use Orion as is, and EUS needs to be made anyway.

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Thought experiment: Constellation esque architecture using SLS, Orion, and a commercial LV.

First, this requires that the development had gone straight to Block 2.

The idea is that SLS launches the lander and a bunch of residuals in the EUS to LEO, where Orion, launched to LEO on a commercial launch vehicle such as Delta IV Heavy or Falcon Heavy (the problem here is that neither are man rated and FH would have been impossible to accurately predict back when the SLS program started) would launch the Orion CSM to LEO where it would dock with the stack and be sent to TLI. The lander or a dedicated stage performs the LOI burn (if lander, altair style) and then the mission proceeds Apollo style from there.

Napkin math is being difficult, but assuming EUS has a dry mass of 15 tons with 460s isp, and Block 2 can get 130t to orbit plus its 15 ton dry mass. Say we have a 24 ton lander and a 16 ton insertion stage (15t prop) lofted to LEO, that's 40 tons of payload, leaving us with about 90 tons of residuals totalling 130t to LEO. The actual number should be more due to the reduced launch mass from not actually having 130 tons of payload, but I don't know how to do that math so I'll stay on the conservative side. Once the 26t Orion CSM docks to it the whole thing will mass 26+40+15 (Orion+lander stack+EUS dry mass) = 81 tons dry and 171 tons wet. Assuming a 460isp engine (~rl10) that gives us about 3.37km/s of Delta-V, enough to do TLI with some margin for boiloff due to rendezvous, or perhaps extra lander/payload/etc mass.

LOI is roughly 850m/s. Apollo was a bit more because it went faster but the minimum is less. Our stack is now the 26t Orion capsule plus the 24 ton lander, plus the 1 ton dry insertion stage and 15 tons of propellant. That gives us 51 tons dry and 66 tons wet. Assuming about 320 seconds of specific impulse (high end hypergolic engine) on the insertion stage engine, this gives us 800m/s. The last 50m/s can likely be provided by the Orion CSM as because all it has to do is the initial rendezvous and the return to Earth burn, likely leaving it with excess Delta-V for the mission at hand. It can potentially do more of the work if necessary, leaving less fuel mass and more lander mass.

Now in LLO we have the 26 ton CSM (slightly less because it used some fuel) and the 24 ton lander. This is definitely not Altair level (46t) but it is quite a step up from Apollo (16.4t).

So now we are placing Orion in a role it was better designed for, we don't have to man rate SLS, we don't have to bother with a lander with enough Delta-V to reach NRHO, we don't have to bother with a multi-piece lander assembled at Gateway, and we don't have to bother with Gateway at all.

It would have been hard to plan from the beginning, however, mostly due to the requirement of a launch vehicle for Orion to LEO, as crew can't launch on Delta IV heavy without significant modifications and Falcon Heavy would have been impossible to predict back then. Plus, FH isn't crew rated although I believe SpaceX have said that it could be. I suppose a design could have been made to fill the role of Ares I, possibly as a commercial competition, although when the SLS program started it was far from certain that any commercial company could build a 26t to LEO vehicle. Maybe modifying the Delta IV Heavy would have been easier.

Switching now also isn't quite advisable, for political reasons, the fact that FH may take a while to man rate, the fact that the new Orion SM may not take well to negative acceleration (although from the beginning this could have been accounted for especially if the original SM design, designed for this, was used and I guess it could be modified for it now) and probably a few other reasons I haven't thought about.

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On 2/8/2020 at 9:03 AM, Ultimate Steve said:

The idea is that SLS launches the lander and a bunch of residuals in the EUS to LEO, where Orion, launched to LEO on a commercial launch vehicle such as Delta IV Heavy or Falcon Heavy (the problem here is that neither are man rated and FH would have been impossible to accurately predict back when the SLS program started)

The SLS is designed to launch Orion, and it is by far the closest to achieving human rating.  The fact is, Orion is a big craft, with room for 6 astronauts, much bigger and heavier than the Apollo return capsules.  The intent is to have a craft more versatile for multiple BLEO operations (cislunar, heliocentric and Mars), and ability to return directly from heliocentric orbit to the Earths surface (ie survive >3km/s re-entry speeds).  The downside of this is that it is just too big to get to LLO and return to Earth in a single launch with current rockets.  A bigger human rated rocket is a decade away at least.

I don't understand the obsession with getting Orion to LLO.   Why is it necessary?  Why not make it standard practice for Orion to enter a highly elliptical orbit, and lunar operations must then be capable of getting to and from the lunar surface from that point?  I simply do not see the downside of that, and creating complex a difficult scenarios to achieve Orion LLO are only going to add cost and time.  

A better question: "Is the Gateway needed?".  I would argue, no.  There is no reason why each mission could be completed with an ad hoc LOR in highly elliptical orbit.  But having a staging point for cargo delivery and a permanent position for advanced comms has some advantages.

Here is my RSS simulation of Artemis 3 which assumes LOP-G is in place, and completes a manned lunar landing with two launches (SLS + FHe).  I think this is basically what NASA is aiming at.  My 3-stage lunar lander meets the spec for HLS, but may be too small in physical dimensions to support 2 astronauts on the surface for 2 weeks.  The current HLS proposals seem to be too large and heavy to complete the mission from a single FHe launch.  The options are single SLS Cargo launch (bad idea, way too expensive) or better two commercial Falcon Heavy launches with EOR. 

 

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