NASA SLS/Orion/Payloads

[T-10a]

Ares V had issues with engine overheating with attached SRBs that would have forced a redesigned RS-68, delaying any major hardware for the Ares V even further behind than the current SLS.
 

[sevenperforce]

2 hours ago, Kerbal7 said:

After a few years Musk and SpaceX could easily be having serious development problems. They might scrap the whole thing for something more economically profitable with a new mission. You know these Falcon 9 fly-backs are still having the occasional failure.

How many RTLS failures has Falcon 9 had?

Because, see, the whole landing thing is still experimental, and they are using flight articles to test the limits of their launch and recovery system. So, yes, successful landing failures are expected. But they've got the RTLS business down. 

2 hours ago, Kerbal7 said:

If you're landing people with supersonic retro-propulsion like the BFR wants to do, you don't have the luxury of those occasional failures. This thing has to work perfect every single time. And I can't see them getting the reliability to an acceptable level to carry John Q. Public commercially. And there goes the whole new opening of deep space because the BFR failed to come.

If you think everyone who's excited about BFR thinks BFR will fly crew without 0-0 LES, you're nuttier than the people who think it will fly people to Mars in 2024 and fly commercial P2P even earlier. BFR has plenty of margin to have an earth-launch crew version with a full capsule lifeboat with 0-0 LES.

Of course, with multi-engine-out landing capability, we may see crewed flights from or to Earth without LES after a few hundred single-engine landings. 

2 hours ago, Kerbal7 said:

I'm confident the SLS and Orion will work. That's why it's my bird.

Well, sure, it will work, and it probably won't kill anybody. But work for what? It's a bridge to nowhere.

32 minutes ago, ZooNamedGames said:

And I just read that the $1b Mobile Launch Structure for the SLS has begun to tilt. No more than 1 launch max from the current structure.

Wow. Seriously? Damn.

[tater]

Course there are only so many RS-25 lying around, so they need another engine for SLS, anyway.

I meant the Shuttle-C concept with the cargo on the side like the orbiter, not a SDLV, like Ares, BTW. That way all the infrastructure would have stayed identical.

This would have given capability with less delay, assuming a SHLV was needed.

[T-10a]

2 minutes ago, tater said:

Course there are only so many RS-25 lying around, so they need another engine for SLS, anyway.

I meant the Shuttle-C concept with the cargo on the side like the orbiter, not a SDLV, like Ares, BTW. That way all the infrastructure would have stayed identical.

This would have given capability with less delay, assuming a SHLV was needed.

I also remember a plan somewhere for a Shuttle-C type vehicle to carry an upper stage and an Orion CSM to orbit as a new crew ship.

[sevenperforce]

10 minutes ago, tater said:

Yeah, sticking the crew on the SRB was an odd idea, lol.

They would have been better off building a drop-tank SSTO out of an SSME.

I haven't done the math, but my gut says you could put an Orion into orbit on a single SSME if you used ROMBUS-style drop tanks and gave Orion a Dragon-2-style LES package that would double as the OMS. Probably cheaper than ARES 1, too.

[Starman4308]

11 minutes ago, sevenperforce said:

Well, sure, it will work, and it probably won't kill anybody. But work for what? It's a bridge to nowhere.

To be fair, Congress is a past master of building bridges to nowhere.

And, more seriously, this is one of my three primary issues with the SLS. It's a bridge to nowhere. It doesn't really open up much in the way of capabilities: it doesn't permit any groundbreaking single-stack manned missions, it's hugely overkill for 99% of unmanned missions, and its launch cadence isn't very suitable for multi-launch missions.

The other two are just its extreme expense and that it goes back on the US government saying "we should never again mix cargo and astronauts", literally using the exact same hardware that inspired the government to make that declaration in the first place.

[Kerbal7]

1 hour ago, sevenperforce said:

Well, sure, it will work, and it probably won't kill anybody. But work for what? It's a bridge to nowhere.

If the SLS and Orion are a bridge to nowhere then why is NASA planning missions around it? I know y'all think our friends at NASA are too stupid to tie their own shoes and your muskssiah is going to build you a golden rocket but...

If SLS and Orion are a bridge to nowhere, then what are these people talking about?? 

 

Edited February 23, 2018 by Kerbal7

[PB666]

10 hours ago, _Augustus_ said:

The whole idea of re-using Shuttle components to save money is incredibly stupid, as re-certifying/upgrading the RS25 and boosters costs so much and takes so long. 

RS 68A is a better launch engine.

9 hours ago, Kerbal7 said:

What makes you think designing, building and certifying a completely new engine and booster would cost less and take less time?  

No need to, there is already an RS68A, much more powerful engine capable of carrying a far bigger payload into space.

6 hours ago, Canopus said:

It seems that before Atlas 3, all Centaurs flew with two engines.

They upgraded the nozzle on the RL10b it had a much longer and wider nozzel (thats what makes it so darn expensive) but it also difficult to place two RL10b-2 engines in most shells. The engine is reliable, its very simple design and probabily does not need to be man-rated in Pairs. But for vulcan progression they are going to ditch the 2-b and go with a smaller C so that 4 engines can be packed.

[PB666]

4 hours ago, Canopus said:

Of course BFR isn't hurting anybody and i too would be excited to see it fly. But should NASA cancel SLS and hope for BFR to fly? What if Musk would really change his mind and stop development.

Because the money would be better spent elsewhere. I supported the shuttle program, but at least it had a performance metric, this SLS program has none. Its seriously bad when the Europeans are calling out their own space agency asking them why they chose such 'questionable' contractors to work on a NASA service module. Who looses if its a mess up, ULA still get 1.3 billion dollars a year just waiting for some contractor in Europe to fail to meet a deadline. Musk has a clear advantage, 'hey dude, that  part you were working on is way behind schedule, we need someone to relocate nuisance sand crabs at the Boca Chica facility, here's your tent'.

[T-10a]

Main issue with the RS-68A is man-rating it (as well as many other changes, though many man-rating issues can be removed in a 'seperate cargo & crew' profile.). Most notably, the RS-68 needs to get rid of the "pre-ignition" (not sure of the official term, but it's the reason why the Delta IV is engulfed in fire before launch) as it can mess up tight engine clusters. The ablative heating is also an issue as it causes significant heating at the base of the vehicle when clustered, which is why the Ares V's RS-68s had to be designed as regeneratively cooled variants (in turn, driving up costs and increasing the Shuttle Gap)

Edited February 23, 2018 by T-10a

[Kerbal7]

31 minutes ago, PB666 said:

No need to, there is already an RS68A, much more powerful engine capable of carrying a far bigger payload into space.

Quote

 

Human-rating

It would reportedly require over 200 changes to the RS-68 to meet human-rating standards.^[13] NASA states several changes are needed to human-rate the RS-68, including health monitoring, removal of the fuel-rich environment at liftoff, and improved subsystems robustness.

 

I'm thinking over 200 changes would have raised the development cost a bit. But I am no one's rocket engineer. So who knows.

 https://en.wikipedia.org/wiki/RS-68

[DAL59]

3 hours ago, Kerbal7 said:

are not about to exist.

Again, they are being built now.

1 hour ago, Kerbal7 said:

If the SLS and Orion are a bridge to nowhere then why is NASA planning missions around it? I know y'all think our friends at NASA are too stupid to tie their own shoes and your muskssiah is going to build you a golden rocket but...

If SLS and Orion are a bridge to nowhere, then what are these people talking about?? 

 

Beurocracy. 

Also, they need to give Boeing money too.

Edited February 23, 2018 by DAL59

[Starman4308]

5 minutes ago, DAL59 said:

Beurocracy. 

Also, they need to give Beoing money too.

They're spelled "bureaucracy" and "Boeing", respectively. Also, blaming everything on bureaucracy is taking a hideously oversimplified view of why NASA has had difficulty accomplishing anything impressive since the Apollo era. It is a non-argument based on a reflexive dislike of bureaucracy rather than any understanding of actual issues NASA might face.

[T-10a]

And despite this "bureaucracy", NASA has at least done some impressive things during the Shuttle Era, even when they were lugged down with the flying brick.

[DAL59]

3 minutes ago, Starman4308 said:

They're spelled "bureaucracy" and "Boeing", respectively.

Sorry 

My spellcheck doesn't work on the forums for some reason...

[Kerbal7]

2 minutes ago, Starman4308 said:

Also, blaming everything on bureaucracy is taking a hideously oversimplified view of why NASA has had difficulty accomplishing anything impressive since the Apollo era.

Apollo was an extension of the Cold War. NASA was on a war footing and come hell or high water the pinko commie punks were going to get beat to the moon. After the race was won, no one knew really what to do with the manned space program. And still doesn't really. 

[tater]

2 hours ago, Kerbal7 said:

If SLS and Orion are a bridge to nowhere, then what are these people talking about?? 

Mars Base Camp is the Lockheed Martin version of Elon Musk's Mars talk.

That said, Mars Base Camp is closer to the current (not Apollo) NASA way, which has them sending 2 of everything out of an abundance of caution.

Each of those LM landers is an SLS just to get to orbit, I think, and another to be sent to Mars as I recall. The central hub is sent ahead (1 SLS), and each transit hub is a launch, possibly 2. Plus 2X Orion with EUS.

So Mars Base Camp requires 10+ SLS launches. About half of those need to happen within days of each other.

Let that sink in.

Edited February 23, 2018 by tater

[PB666]

2 hours ago, Kerbal7 said:

Vehicles that can land hundreds of tons of whatever to Mars do not exist and are not about to exist.

Interplanetary transport can be broken down into two types of problems.

1. Bulk transport
2. Time sensitive transport.

Getting bulks of Materials to Mars given the current launch structure is not hard it just requires patients and lots of planning. If you can get the material to LEO no 70 tons or so. To do this we need a construct. IN the construct we have a plate with mounts on both ends  and a center that can mount 200s of tonnes. The plate itself and its engines might weight 20 tons, Another 20 tons for solar panels. There are tanks, they can hold several tons of hydrogen and oxygen. The plate empty is shipped to orbit. You can load the Bulk plate with cargo, this would take 3 shipments. So now the plate is full. Also you have tanks for Argon. Next you ship up and transfer the hydrolox fuels (the transport has a gas liquid recycler to recapture the blow off). The ship then burns to a highly elliptical orbit with its single 277 kg RL10b-2 engine. The ship however maintains about 1000 reserve dV of gas. Once there (using 0 as periapsis) it begins ION driven burns from -135' to 135 degrees with a slight retrograde burn at 180' to maintain the periapsis at ~ 6870 km. Once the last kick is initiated in burns the last 1000 dV of hydrolox placing it on a trajectory toward mars. The ship has however limited rentry capability. The next manuever it uses its ION drives to place it at S-M L1 and then it places itself in a highly eccentric orbit around mars using the martian atmosphere to break its speed, which at a certian point it circularlizes near the apoapsis and releases its payloads. This ship then returns to Earth on a long time frame using highly efficient ION power. Average round trip time 4 years, the transporter is considered fully depreciated after 5 trips and given interest rates its cost per trip is roughly 30% of the cost to build a new one, plus the cost of the argon, H2 and O2 shipments.

There are two basic strategies 1. to aerobrake into Mars  that part of the payload is liquid oxidant (NO2) and fuel, in which you use the atmosphere to decay to a certain point and then you burn back the remaining 3200 dV. There is basically no size limit, and you probably could bring in 200 tons, its just that you would only land about 50 tons (suitable for large items like nuclear reactors, drilling equipment or ISRU facilities) . The second strategy is to Aerobrake in parts. Basically instead of trying to land 200 tons you land 20 tons 10 times. (this is suitable for bulk goods like metal, food supplies, . . . .) Just to take care of the Mars dreamer argument, this will not build a city of a million, but you could build a decent science outpost on Mars. There is an additional, if one of the landers has enough fuel storage to return to orbit, then other landers could bring the fuel, it could be refueled on Mars, and if a crew quarter is attached it could carry crew back to LMO which other transporters could be used to get them back to Earth. One potential use of the tanks, for example aluminum tanks is that you could forge winglike fuel tanks, basically that fly at hypersonic speeds and finally turn high drag spoilers to slow the wind down and simply allow it to crash into the surface. The fuel is then gathered and the tanks aluminum is used as a raw material. Large enough wings could be made by have the wings launched in sections and assembled by robots in LMO. 

Time sensitive transport is a different issue (i.e. humans or precious liquefied gases) this probably would not be done well with ION drives and so the total tonnage is rather limited because of the mean ISP of the fuel. Essentially any of these systems SLS/Orion, BFR, Alt. FH  could get a vehicle into LMO with proper support in LEO and proper reentry vectors around mars. A cycler could bring fuels to the vessels in LMO and they could land on Mars . . .but without support those ships will never leave Mars. So that unless there is a plan to send to mars the facilities and supplies (Not ISRU, but the actual resources) those who travel to mars on current technologies are doomed to die on Mars as those technologies eventually fail them.

We have to separate the two missions, we currently are not used to the idea of bulk missions, because other than the ISS, we are not used to stockpiling large amounts of non-perishable materials in space. But if we abstractly think that this 'in space storage' is doable, and it simply represents the cost of getting bulk into LEO, and an aggregate of cost depreciated over time for slow transport then there is no reason to not consider a bulk material allocation around Mars. The way that you can model this is the intercoastal canal. As it was originally built is was for light (low draft ships) ships, barges and civilian and military use (deep enough for a destroyer but too shallow for a submarine). But over time given the canal, the low draft ships are gone, barges have evolved to carry 4, 8, double wide barges  . . .almost as much cargo as a Ocean going ship with a fraction of the dedicated infrastructure. Then think of transporters of goods as everything that does not need to go along side of humans and that can just be loaded into any container.  For example if its 100 days for humans, one set of clothes, minimal personal hygiene stuff, 100 days worth of air, water and food, no mass-expensive waste recycling.

So that the design of a ship for bulk transport has fewer constraints than a crew rated or science rated vessel. because of this it can carry more.

 

[PB666]

1 hour ago, Kerbal7 said:

I'm thinking over 200 changes would have raised the development cost a bit. But I am no one's rocket engineer. So who knows.

 https://en.wikipedia.org/wiki/RS-68

Or raised by their desire to use the RS25.

RS-68A 3 times more powerful. And BTW, those boosters are not safer, and yet SRBs are being used. If you have a 4 RS68A and you run into a problem with one of the engines, you can kill it, the three remaining will still probably take you to orbit. You can throttle them down. 

Its not a matter of 'if' a next SRB caused disaster will occur, its a matter of when.

[tater]

Not to mention that they either start making new RS-25s, or they might as well make RS-68A. How many old SSMEs do they have?

[ZooNamedGames]

30 minutes ago, tater said:

Not to mention that they either start making new RS-25s, or they might as well make RS-68A. How many old SSMEs do they have?

I’ve recently heard 16 iirc, but don’t hold me to that statement. 

[Bill Phil]

37 minutes ago, tater said:

Not to mention that they either start making new RS-25s, or they might as well make RS-68A. How many old SSMEs do they have?

RS-68s would require even more work to get them to work on SLS. It's designed for SSMEs. So they're basically stuck with building new ones. The RS-68 isn't an option. It is a hydrolox engine, but its isp is less than the SSME by a decently sized margin.

7 minutes ago, ZooNamedGames said:

I’ve recently heard 16 iirc, but don’t hold me to that statement. 

Yeah. They've got 16 in storage. And none of them are really consistent with each other. Which means that individual engine choices will impact vehicle performance.

[tater]

This is the consistent problem with this program. So they get to EM-4, and either make new RS-25s (super expensive for engines that are never going to be reused, but thrown in the ocean), or make an alternative, that then requires man-rating. Better to just fly the things from the start.

Wow, 412s vs 452s. Big difference since they are really sustainers.

[Bill Phil]

6 minutes ago, tater said:

This is the consistent problem with this program. So they get to EM-4, and either make new RS-25s (super expensive for engines that are never going to be reused, but thrown in the ocean), or make an alternative, that then requires man-rating. Better to just fly the things from the start.

Yeah. The decision to use "off the shelf" technology really shot the whole program in the foot. They had to essentially redesign the SRBs and have to re-engineer the SSME/RS-25. Not to mention develop two upper stages (even though one is based on an existing upper stage). And all without enough payloads to really justify its existence. Even the Shuttle technically had payloads to fly, and it could fly at much higher rates. All SLS has is Orion.

I sure hope that NASA will be able to move on after this whole debacle. It should be flying by last year.

Quote

Wow, 412s vs 452s. Big difference since they are really sustainers.

Yeah. That's part of why they're using SSMEs, since you could technically take the core all the way to orbit. The core is the orbital insertion stage, basically, but they're going to fly a trajectory that can dispose of it.

Edited February 23, 2018 by Bill Phil

[T-10a]

Did the math:

RS-68 powered SLS:  9856.47 m.s.-1 dV

RS-25 powered SLS: 10813.41 m.s.-1 dV

That extra 1000 m.s.-1 can be really important, and allow greater payload to orbit.

(DO NOTE: This was done with assuming only the core of the SLS's mass, no strapon SRBs, and TWR is irrelevant.)

Edited February 23, 2018 by T-10a