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NASA SLS/Orion/Payloads


_Augustus_
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21 hours ago, _Augustus_ said:

Boeing is now running propaganda promoting and taking credit for SLS, acting like Dragon 2 doesn't exist, claiming FH is useless, etc.

http://nasawatch.com/archives/2018/04/boeings-mislead.html

Here's another take on it: https://arstechnica.com/science/2018/04/boeing-slams-the-falcon-heavy-rocket-as-too-small/

The author wasn't all that interested in the story (besides disgust from Boeing jumping in the "Fake News" industry), but does note that the story "for more information" that Boeing linked quoted his website (arstechnica) as the only source.

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At this point I'm half expecting them to have a warehouse full of JWSTs and SLS parts just in case something goes wrong with the "real" ones.

"First rule of government spending: why have one, when you can have two for twice the price?"

Edited by Mitchz95
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Can anybody explain to me why they want to have one rover take samples and another rover to fetch the samples back to a return vehicle? Can't the first rover bring them back? Or maybe land the return vehicle somewhere and the first rover drives to it.

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1 minute ago, mikegarrison said:

Can anybody explain to me why they want to have one rover take samples and another rover to fetch the samples back to a return vehicle? Can't the first rover bring them back? Or maybe land the return vehicle somewhere and the first rover drives to it.

Mass to the surface. They don't want to have to build a lander capable of digging stuff up as well as an ascent vehicle on the same craft I think.

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Just now, tater said:

Mass to the surface. They don't want to have to build a lander capable of digging stuff up as well as an ascent vehicle on the same craft I think.

No, that can't be it.

The plan is to send the sampling rover in one mission and the "fetch" rover plus MAV in another mission. But my question is, why a "fetch" rover at all? Why not have the sampling rover bring the stuff back? If they didn't have a fetch rover, then they could have a bigger MAV and carry back more samples.

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5 minutes ago, mikegarrison said:

No, that can't be it.

The plan is to send the sampling rover in one mission and the "fetch" rover plus MAV in another mission. But my question is, why a "fetch" rover at all? Why not have the sampling rover bring the stuff back? If they didn't have a fetch rover, then they could have a bigger MAV and carry back more samples.

Oh, why not make the sample rover capable of depositing the samples in the MAV? Good question.

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9 minutes ago, mikegarrison said:

No, that can't be it.

The plan is to send the sampling rover in one mission and the "fetch" rover plus MAV in another mission. But my question is, why a "fetch" rover at all? Why not have the sampling rover bring the stuff back? If they didn't have a fetch rover, then they could have a bigger MAV and carry back more samples.

To keep the smaller rover busy and make it think its job is important, of course.

It could be either because they want to avoid some sort of contamination (?) and/or to not put more fatigue on the bigger and more important rover. They would probably rather do more science instead of driving back and forth to fetch the tubes.

Edited by Wjolcz
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When Apollo 11 landed, the first thing they did on EVA was to bag a small contingency sample so that if they had to leave, they'd have something.

Seems like any sample return should have some sort of arm that dumps a sample so that if for any reason they need to go, or if the rover(s) fail, they can still accomplish a return.

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3 minutes ago, tater said:

When Apollo 11 landed, the first thing they did on EVA was to bag a small contingency sample so that if they had to leave, they'd have something.

Seems like any sample return should have some sort of arm that dumps a sample so that if for any reason they need to go, or if the rover(s) fail, they can still accomplish a return.

Good point. It would be really embarrassing if the big one broke down halfway to the MAV. The MAV would stand there empty and the rover would stand there immobilised. That's a very silly way to end a mission.

Edited by Wjolcz
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16 minutes ago, Wjolcz said:

Good point. It would be really embarrassing if the big one broke down halfway to the MAV. The MAV would stand there empty and the rover would stand there immobilised. That's a very silly way to end a mission.

Right. But if it requires *two* rovers to work correctly in order to accomplish the mission, then you actually get twice as big of a chance of such a failure occurring.

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That's really dumb in that case. I can see the benefit of a rover collecting stuff over time, then if it can make it, depositing samples for return, but only if the return mission can get samples as a default.

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I presume that the second rover will have the necessary hardware for handing off the samples to the MAV...which hasn't even been designed yet, so the first rover couldn't have been built to do that job. And the first rover may want to end its mission driving into territory that is not particularly friendly to a lander...so it's better to dump its samples in a place where the pickup rover can grab them to load them up onto the MAV. And the 2020 rover may no longer be operating by the time NASA finally gets around to building a MAV.

Edited by Brotoro
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55 minutes ago, Brotoro said:

I presume that the second rover will have the necessary hardware for handing off the samples to the MAV...which hasn't even been designed yet, so the first rover couldn't have been built to do that job. And the first rover may want to end its mission driving into territory that is not particularly friendly to a lander...so it's better to dump its samples in a place where the pickup rover can grab them to load them up onto the MAV. And the 2020 rover may no longer be operating by the time NASA finally gets around to building a MAV.

OK, that's a scenario that maybe makes sense. If the sample rover has to be designed and built before they know the details of the rest of the mission, that could be the issue.

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27 minutes ago, mikegarrison said:

OK, that's a scenario that maybe makes sense. If the sample rover has to be designed and built before they know the details of the rest of the mission, that could be the issue.

I think this is actually it. Gioven budgets, the slow speed of rovers, and the synodic nature of Mars launch windows, they are breaking it up a little. One goes, then the next can perhaps pick up some interesting samples from the first rover.

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I'd heard the SLS was being designed for trips to the moon, but I had no idea they were going to try that on the second launch! I'm not concerned about the launch hardware, but mostly about that pod. That's a long trip with no abort options and a really burny return. [wiki /wiki] Well, I hope for good success on their uncrewed EM-1 'dress rehearsal' mission! I hope for great and continued success, or for an immediate and informative failure.

OK, thanks for the clarification @tater. Back on topic!

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4 minutes ago, Cunjo Carl said:

I'd heard the SLS was being designed for trips to the moon, but I had no idea they were going to try that on the second launch! I'm not concerned about the launch hardware, but mostly about that pod. That's a long trip with no abort options and a really burny return. [wiki /wiki] Well, I hope for good success on their uncrewed EM-1 'dress rehearsal' mission! I hope for great and continued success, or for an immediate and informative failure.

OK, thanks for the clarification @tater. Back on topic!

And until very recently, that second flight would also have been the first flight of Block 1b. So, launching crew on a completely untested configuration, too. :rolleyes:

So yeah, it bugs me when NASA obsesses over the "history" of the Falcon 9 when they're planning this.

Also, the heat-shield was tested with the help of a Delta IV Heavy on this mission a few years ago, so it has been sort-of tested. But nowhere near what Apollo went thru.

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2 hours ago, Cunjo Carl said:

I'd heard the SLS was being designed for trips to the moon, but I had no idea they were going to try that on the second launch! I'm not concerned about the launch hardware, but mostly about that pod.

It's not a pod, it's a capsule.

2 hours ago, Cunjo Carl said:

That's a long trip with no abort options and a really burny return. [wiki /wiki] Well, I hope for good success on their uncrewed EM-1 'dress rehearsal' mission! I hope for great and continued success, or for an immediate and informative failure. 

It's free-fly slingshot trajectory around the Moon, like Apollo 8. Also, it has redundant propulsion systems, which makes it safer than Apollo:

  • 1 primary AJ10 engine (recycled Shuttle OMS)
  • 8 Auxiliary thrusters for backup
  • RCS thrusters for backup of the backup

I would have been more comfortable with a LEO flight for easy abort in case of any issues with the other systems, but at the cost of the system and with a flight rate of 1 every 2 years, an extra test flight only pushes back the program even further.

 

2 hours ago, CatastrophicFailure said:

Also, the heat-shield was tested with the help of a Delta IV Heavy on this mission a few years ago, so it has been sort-of tested. But nowhere near what Apollo went thru.

Wasn't the heat shield completely redesigned after EFT-1 ?

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3 hours ago, CatastrophicFailure said:

And until very recently, that second flight would also have been the first flight of Block 1b. So, launching crew on a completely untested configuration, too. :rolleyes:

So yeah, it bugs me when NASA obsesses over the "history" of the Falcon 9 when they're planning this.

So was the shuttle. And it flew its first flight crewed. And Orion has a different LES (tested, I presume) than Dragon (also tested).

But then all this feels like they are trying to prove SLS just isn't that useless. I'm not one of these conspiracy guys, but maybe NASA is trying to slow down the progress of Dragon to launch crewed Orion before crewed Dragon (F9 needs like 7 flights unmodded to be considered crew rated). Let's be honest tho: they probably won't. I know both capsules are for something different but taxpayers don't care, right? A spacecraft is a spacecraft to most of them.

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5 hours ago, Nibb31 said:

Wasn't the heat shield completely redesigned after EFT-1 ?

I think it has been changed a little, but they are still making it Apollo style, by hand. I don't think the fundamental design has changed... I'll have to look and see what I can dig up.

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I guess I'll go look up the definitions of pod and capsule, thanks.

To explain my position a bit, I'm absolutely positive they can make a great capsule for use in the long run, but from the looks of it it's still in the design phase, and I have a hunch that no one on the team has ever designed, tested or prototyped a capsule before this one :D . They have tons of experience and I'm not trying to sell that short, just how should I put it... As a prototyping engineer myself, I'll say I'm glad it's not my job. Making sure you find all the problems in a newly designed and complicated system with only mockup-tests and a single dry run is hard. And I really do wish them the best!

... This leads to an important question. Do you think they still send up duct tape?

Does Elon send up duct tape :o

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