SLS General Discussion Thread 8

[pochimax]

My reasoning is that if both HLSs fail (something I consider unlikely), then NASA will build its own.
It will take as long as it takes, I don't know... in the meantime, Orion would fly to the Gateway.

That doesn’t make sense. NASA can’t build its own. It’d need contractors to do it. It’d also need to find $30B somewhere.

SLS/Orion can also fail. They are also built by contractors.

It was a figure of speech, and you took it literally.
What didn't make sense was asking the question "who would do it." It was obvious the US government would find a way to solve that problem. I wasn't interested in that part of the debate; I don't care if it was a CLPS derivative, a NASA-led design, or a Euro-Japanese solution... the argument is that some alternative would be studied and approved. Absolutely.

I don't understand the insistence on a scenario in which Orion and the SLS for Artemis III and IV would be meaningless if the SpX HLS failed, for any reason, or was delayed excessively. I don't find the argument reasonable. The failure or problem with one component of the lunar architecture cannot mean that the entire thing would be canceled in a kind of lunar hara-kiri. If their missions were meaningless, it wouldn't be their fault but that of the HLS. While a solution to the failed component emerges, it's obvious there would be a gap, without surface missions, but that's inevitable.

[JEF_300]

[...] SLS/Orion has exactly one plausible mission:  delivering astronauts to an NRHO rendezvous with an HLS.

Or with Gateway.

But there is no reason to send Orion to gateway unless there is an HLS.

I think that's a bit strong of a statement. There are loads of potential missions to be done at Gateway without a lander (deep space radiation exposure, Mars mission transit simulation) and some of them are even sensible ideas (Orion test flight, science in a deep space environment). We can and should argue about how worthwhile these reasons are, but there are definitely reasons.

Deep space radiation exposure of astronauts? Ethical concerns aside: Gateway isn't going to be occupied for long enough to get any good data on that.

Those are all missions NASA itself has argued in the past that Gateway could be used for. Particularly back under Bridenstine, where support from the top was stronger. I just restated them.

(NOTE: I don't think NASA ever quite explicitly stated that deep space radiation exposure of astronauts was a goal of Gateway, but they did mentioned a simulated Mars transfer flight in NRHO, and then mention radiation, so...)

[Robotbeat]

It’s a bad rationale. We don’t need humans to measure radiation, and in fact humans are the worst radiation sensor you could imagine. You don’t measure UV light using sunburn induced skin cancer rates. If some NASA person gave that as the rationale (which I don’t think they would), then that NASA person is wrong.

[pochimax]

It’s a bad rationale. We don’t need humans to measure radiation, and in fact humans are the worst radiation sensor you could imagine. You don’t measure UV light using sunburn induced skin cancer rates. If some NASA person gave that as the rationale (which I don’t think they would), then that NASA person is wrong.

this is not the plan, sensors will be installed both inside and outside the HALO module. They will collect data from launch.

https://www.nasa.gov/missions/artemis/lunar-gateway-science-payloads/

Furthermore, the arrival of astronauts will allow for experiments similar to those on Artemis I, using mannequins and protective vests, but for much longer durations. For example:

https://www.dlr.de/en/latest/news/2024/orion-spacecraft-radiation-protection-tested-initial-findings-from-artemis-i-moon-mission

[Robotbeat]

None of that requires gateway.

[pochimax]

None of that requires gateway.

I suppose you could launch a satellite with sensors to make measurements of this type, relative to the exterior of a spacecraft. That's not cheap. Much less launching satellites to cover the time period provided by the Gateway (15+15 years) covering different phases of the solar cycle.

But you're very unlikely to obtain measurements of the interior of a spacecraft. To do that, you'd have to launch a "simulator satellite" of a Martian transit habitat, with sufficient volume and mass to realistically recreate the interior of such a craft. This doesn't exist and has never been done. Designing, building, launching, and operating a simulator module of this type will also cost a lot of money. And if you want to obtain 15+15 years, you'd have to send more than one. Something like that isn't realistic and isn't going to happen.

This kind of knowledge that the Gateway will provide can only be obtained because it is Gateway-enabled science. There are no feasible alternatives; these experiments simply wouldn't be done.

Furthermore, since the Gateway is visited periodically, the astronauts' availability would be used to reconfigure the protective elements and test different strategies after each flight, cost-effectively since the astronauts are there.

Furthermore, ESA is very interested in these types of experiments, so the cost to NASA may even be zero.

[Robotbeat]

MSL Curiosity flew to Mars with such a sensor, collecting data the whole time. That’s far more relevant to a Mars mission as it literally flew to Mars and is now also collecting data on the surface.

[pochimax]

MSL Curiosity flew to Mars with such a sensor, collecting data the whole time. That’s far more relevant to a Mars mission as it literally flew to Mars and is now also collecting data on the surface.

It was an interesting experiment, but it hasn't been repeated*, nor are there any plans to do so in the short or medium term. Furthermore, it doesn't simulate the same type of protection that the MTH would provide, it's not capable of measuring data on different parts of the body-mannequin, and it doesn't support minimization strategies (vests, material accumulation, etc.), all of which can be done only on the Gateway. Furthermore, the Gateway isn't limited by Martian launch windows and will operate for 15+15 years.

* I forgot about that german sensor on a Chang'e landing mission. Again, not the same cuantity nor cuality of the data.

[FinalFrontier]

We will see what ultimately is passed by congress.
Many times presidents have tried to kill the POR pork fondue fountain, basically all have failed.

With that said:
If anyone who is a supporter of spaceflight wants to get to the moon and mars, or have a permanent presence on either or both, SLS+ORION would absolutely guarantee it Does NOT happen.
The system basically doesn't work or barely works, is un affordable, and can't launch enough. In fact barely launches at all.

Cancelation of SLS has been long overdue the question now is what is the path forward for the moon and Mars?
Hopefully simply doing true commercial launch bidding will be what happens.

[FinalFrontier]

... and its large galley and separate bathroom that Orion was loaded down with needless and unnecessary requirements that have compromised its design and development ever since.

FWIW...

While I am not a fan of Orion by any stretch of imagination, I would argue in favor of the bathroom. It is exactly the kind of improvement in spacecraft design one would expect to see as launch capabilities improve and on-orbit lessons-learned contribute to spacecraft design. Having said that, this "bathroom" is a bad joke. The toilet itself is fine though, and is called the Universal Waste Management System (UWMS). This system separates urine for release into space and stores feces for disposal upon the return of the various cargo spacecraft. Releasing the urine into space is a technology step backwards into the past. Why is the urine not recycled?

Recycling on the International Space Station (ISS), specifically for water - including urine - began with the installation of the Water Recovery System (WRS) as part of the Environmental Control and Life Support System (ECLSS). The key milestone came in November 2008, when the first major components of the WRS, including the Urine Processor Assembly (UPA) and Water Processor Assembly (WPA), were delivered to the ISS aboard the Space Shuttle Endeavour during the STS-126 mission.

The system started operational testing shortly after installation, with the goal of recycling urine and other wastewater into pure, potable water. By May 2009, NASA reported that the crew drank recycled water for the first time from this system, marking its functional debut. Early tweaks were needed—like fixing distillation issues with the UPA—but it’s been a cornerstone of ISS sustainability ever since then, evolving with upgrades over the years.

So the urine is not dumped overboard on the ISS. It is recycled, purified and reused for drinking water, food rehydration and is fed back into the station's plumbing. But NASA's flagship spacecraft can't do this? Another black eye for NASA and Lockheed-Martin. With the amount of money being spent on this spacecraft, I would expect better from them both.

Orion would never be able to do re processing in any of its forms past or present including pre ZBV.

Doesn't have enough room for the UPA rack or something that large.

But I can think of two vehicles, one of which is already built, that do have that space.

[pochimax]

I' m not the only one who thinks is a good idea to put an EUS on top of a Starship. 

https://twitter.com/DJSnM/status/1919083918424236507

[sdsds]

I' m not the only one who thinks is a good idea to put an EUS on top of a Starship. 

EUS makes sense as an upper stage for a launch system that flies once or maybe twice a year. RL10 is an expensive engine though. For EUS NASA payed ~$27M each on a quantity 10 contract (NNM16AA12C) and each stage flown expends 4 of them.

[lightleviathan]

Maybe Impulse could make a 9m wide Helios with 6 engines and call it a day, which would be compatible with Starship. But that's not related to SLS.

[sdsds]

Maybe Impulse could make a 9m wide Helios with 6 engines and call it a day, which would be compatible with Starship. But that's not related to SLS.

What Manley doesn't consider is that the only currently operating pad with both methane and hydrogen is operated by Blue Origin. 6 x Deneb engines from Helios would get around that elegantly and yet apparently making NASA launch systems is a lot like making pork sausage; Impulse doesn't seem likely to be part of that process. If someone wanted to get L3-Harris (Rocketdyne) on board with a new plan, giving them an MB-60 contract might do the trick. Expander bleed; impressively high chamber pressure; easily adaptable to methane. To appease Boeing they get a contract to redesign EUS with tanks sized for methane. Lockheed gets to continue (over-) charging for Orion. Northrup-Grumman (Thiokol) is left a bit out in the cold, but they're suddenly busy with non-civilian rockets so maybe that's okay.

[Robotbeat]

Well, Vulcan, too, of course. It’s not that big of a deal just for an upper stage. Falcon 9 flies the methane-fueled Intuitive Machines landers, after all. Maybe 20 tons of hydrogen.

[spacenut]

If we are Legoing rockets, what about New Glenn's upper stage on a Superheavy as a 3rd Stage?  Could launch quite a lot. 

[Robotbeat]

If we are Legoing rockets, what about New Glenn's upper stage on a Superheavy as a 3rd Stage?  Could launch quite a lot.

Indeed. And BE-3U gets literally 10 times the thrust as RL-10, so the 2 BE-3Us are equivalent to about twice the thrust as the EUS, so you could easily afford to stretch the stage to more than the EUS.

Instead of 120t of prop, let’s say 200t.

[pochimax]

Interesting.

In that case, it might be interesting to simply manufacture the hydrogen tank and let BO handle the rest. I don't know if BO has the necessary tooling to build larger diameter tanks than the current ones.

In any case, I think a third stage for Starship is something NASA should explore (even if it's then carried out by industry, as it always has been).

But this is really a capability that would only interest NASA, so it's not something that has a quick fix or can be leveraged for commercial uses.

[Robotbeat]

Or Lockheed martin