NASA SLS/Orion/Payloads

[tater]

5 minutes ago, Canopus said:

What Rocket other than the Saturn V was built with a specific payload in mind?

The payload need not be specific as built, but when the LV is expendable, then it needs to be a vehicle that is cost-effective to use for a class of payloads that people want to send to space.

The problem with SLS has always been lack of payloads. ARM was make-work, too. 

We could all envision giant space probes, for example. Landers for all the interesting moons! Mars sample return, etc. Great, but giant probes result in giant costs. If NASA can only fund 1 giant probe every X years, how does SLS get tot he required cadence of 2+ launches per year? The claimed marginal launch cost is what, 500M? At 2 launches per year, and a 2+B$ fixed cost of keeping the program going, each launch ends up really costing ~1.5B$. That means any payloads should justify that sort of expense, vs a launch 15X cheaper.

[Canopus]

But now that they have a payload and a destination isn‘t the while point moot? There isn‘t really another launcher that can support a Space station in Lunar Orbit and once they start building the DSG, nobody will cut the Funding and end the SLS. And since the budget for probes is seperate from manned missions (atleast i think it is) i don‘t really see the downsite to the whole thing. And seeing that the ISS has attracted companys like Orbital ATK and spacex i think it can only help in the private sector too

Edited October 7, 2017 by Canopus

[tater]

Circular. I'm not sure what the point is of a station out by the Moon. It's not even much of a station. Lunar orbit rendezvous was chosen for Apollo, because it minimized the mass required to LLO. DRO (or NRO) adds a couple km/s to the lander's dv requirement. A reusable lander then requires a prop depot.

It will be interesting to look at the logistics of suppling DSG with props for landers. How many flights, and of what vehicle, at what cost per full lander tank?

[Canopus]

7 minutes ago, tater said:

Circular. I'm not sure what the point is of a station out by the Moon.

Support of unmanned surface mission like teleoperating robots with less delay? Construction and servicing spacecraft for missions to asteroids and maybe eventually Mars, testing manned spaceflight outside the Earths Magnetic field. Atleast thats what Nasa themselves suggest. Who knows what international Partners will do with the station?  I think it offers more possibilities than the ISS.

[Nibb31]

9 minutes ago, Canopus said:

Support of unmanned surface mission like teleoperating robots with less delay?

The delay with the Moon is negligeable, and teleoperating is pointless with more autonomous robots.

9 minutes ago, Canopus said:

Construction and servicing spacecraft for missions to asteroids and maybe eventually Mars, testing manned spaceflight outside the Earths Magnetic field. Atleast thats what Nasa themselves suggest. Who knows what international Partners will do with the station?  I think it offers more possibilities than the ISS.

It actually offers barely more possibilities than the ISS, but at a much higher cost.

[tater]

It's also higher risk for the crew for multiple reasons, including radiation exposure. The crew by default will experience >2X the radiation they do at ISS. DSG is better than wasting SLS launches I guess (since it's flying regardless of what is the best way to spend X billion $ every year), but it's make work.

[Canopus]

18 minutes ago, Nibb31 said:

The delay with the Moon is negligeable, and teleoperating is pointless with more autonomous robots.

Wouldn‘t the roundtrip for control and feedback be something like 3 seconds? Let‘s say you where to conduct some kind of critical work on the Surface like building a habitat (i know its unlikely to happen soon) wouldn‘t it still be beneficial to control or atleast monitor something like the Canadarm in realtime? 

Well maybe it‘s just wishfull thinking on my part. I guess i am just happy to see people leaving LEO for the first time in 50 years.

Edited October 7, 2017 by Canopus

[Bill Phil]

2 hours ago, tater said:

Circular. I'm not sure what the point is of a station out by the Moon. It's not even much of a station. Lunar orbit rendezvous was chosen for Apollo, because it minimized the mass required to LLO. DRO (or NRO) adds a couple km/s to the lander's dv requirement. A reusable lander then requires a prop depot.

It will be interesting to look at the logistics of suppling DSG with props for landers. How many flights, and of what vehicle, at what cost per full lander tank?

You can send more payload to L-2 than to TLI. Thus, pooling resources at L-2 could be beneficial for Lunar activity.

I personally think the DSG plan is a good idea. We really have no experience for long term space flight beyond LEO. Gaining that experience is a good idea if we desire to go to Mars. Also, I think NASA is underselling DSG's size, or at least not planning for the future in a realistic way. There will likely be at least two (if not four, SLS, FH, NG, and VH) LVs that will be able to service DSG. Maybe some Bigelow modules could find their way there, too. 

LOR was chosen for Apollo to minimize time, and, to an extent, mass to TLI. If I remember correctly, DSG as currently proposed is a mobile station. Maybe it could deploy landers in LLO and wait for them there? But that's just speculation.

[DAL59]

If DSG was a fuel depot, it would make more sense.  But there is not anything in lunar orbit different than in LEO, other than the view.  Yes, the radiation is greater, but it has been accurately measured by many spacecraft, including the curiosity, and it not much of a problem.  The solar radiation is easily blocked by a small shelter or even just water filled sleeping bags, and the GCR is less than that experienced by Russian cosmonauts.  

[Bill Phil]

9 minutes ago, DAL59 said:

If DSG was a fuel depot, it would make more sense.  But there is not anything in lunar orbit different than in LEO, other than the view.  Yes, the radiation is greater, but it has been accurately measured by many spacecraft, including the curiosity, and it not much of a problem.  The solar radiation is easily blocked by a small shelter or even just water filled sleeping bags, and the GCR is less than that experienced by Russian cosmonauts.  

L-2 =/= Lunar Orbit

The Delta-v from L-2 to useful targets is low. As a fuel depot, it would be best. Currently there are "plans" to use SLS flights to "refuel" DST. DSG will probably evolve into a depot over time. Gotta start somewhere. 

[James M]

On 5/12/2017 at 4:34 PM, tater said:

Or they could use a centaur/ACES variant. Centaur is bulletproof, and NASA stuff intentionally spreads stuff out. SLS/Orion employs thousands of people in 44 States. Hence broad support...

 

 

What movie is this? I have to see it.

[tater]

27 minutes ago, James M said:

What movie is this? I have to see it.

Seriously? LOL.

The Right Stuff.

DRO and NRO are not bad orbits, really. 

[_Augustus_]

2 hours ago, James M said:

What movie is this? I have to see it.

The Right Stuff. Pretty good movie but kind of long and with a lot of fictitious elements thrown in - for instance, the scene in that video never happened and the Mercury capsule was designed by a Belizean-born American, not a German.

Edited October 8, 2017 by _Augustus_

[tater]

 

[Ten Key]

Quote

Now, seven years later, NASA is finalizing the upgrades to the mobile launcher that will be used for the maiden flight of the SLS rocket, likely no earlier than December 2019. However, there's another problem. Because the SLS's upper stage will be upgraded between this first flight and second flight (Exploration Mission-2, or EM-2), the larger and longer upper stage will necessitate significant changes to the mobile launcher.

-- Arstechnica article linked above

Oh for cripes sake. . .did NASA really not see that coming? 

[tater]

NASA is saving money by using the ICPS, since they already have it, even though it will cost north of the 500 M$ already spent as linked above, plus however much time to build VAB and pad facilities twice. Plus 33 months delay (at 2+ B$/year program costs).

Remember, kids, it's a jobs program, not a space program.

[_Augustus_]

I think that the EUS will be cancelled in favor of something like the old EDS for cargo and we'll see crew missions and Europa Clipper flown on Block Is.

[tater]

 

[Mitchz95]

To be honest, I'd be perfectly fine with the moon over Mars as long as we actually did it for once.

[tater]

Worth a look:

http://www.spudislunarresources.com/blog/flight-of-the-space-turkey/

He's spot-on about the useless, ATV-based ESA service module. That should be killed with fire, and replaced with a real SM that has reasonable dv. There is no reason that if we have to fly SLS/Orion (and we're stuck with it), it should use a sub-standard SM that cannot do lunar work for lack of dv.

[kerbiloid]

45 minutes ago, tater said:

He's spot-on about the useless, ATV-based ESA service module. That should be killed with fire, and replaced with a real SM that has reasonable dv.

+1
Let them use Salyut, it has docking ports from both sides.

[wumpus]

On 10/7/2017 at 10:45 AM, Canopus said:

What Rocket other than the Saturn V was built with a specific payload in mind?

R7, Redstone, and Atlas were all built with suborbital nuclear warheads in mind.  Mercury and Vostok were presumably built with their respective capsules in mind (based on rockets designed as ICBMs).

While it would be a wild exaggeration to claim that the Shuttle was "built with keyhole in mind", the Shuttles dimensions, cargo capacity and return capacity were dictated by the spy satellite.

Google (and lost bookmarks) have let me down, but from memory one of the "rules of rocketry" is "any mission involving a new launch method becomes a launch project".  Rockets built for specific missions are budget breakers and can only be expected for "milestone" missions.

[Canopus]

12 minutes ago, kerbiloid said:

+1
Let them use Salyut, it has docking ports from both sides.

Salyut is a Space station though not a service Module i don't see the connection there. About the delta v, i guess not they don't need that much for the Missions planned with the Orion. It seems like it doesn't take as much fuel to get to the Distant Retrograde Orbit or near rectilinear Halo orbit as opposed to low Lunar Orbit.

[tater]

Heavy lift is a fine general capability to have, so SLS is not the worst thing, except for cost.

Orion, otoh, is not really good for anything. The SM is a case where the mission absolutely matters, because that defines what the dv of the SM should be.

DRO was picked because Orion can do it, it wasn't the goal of Orion, hence a crippled SM with 1000 m/s less dv than The Apollo CSM.

[Nibb31]

1 hour ago, tater said:

Worth a look:

http://www.spudislunarresources.com/blog/flight-of-the-space-turkey/

He's spot-on about the useless, ATV-based ESA service module. That should be killed with fire, and replaced with a real SM that has reasonable dv. There is no reason that if we have to fly SLS/Orion (and we're stuck with it), it should use a sub-standard SM that cannot do lunar work for lack of dv.

I'm European, and I agree. The ESM is too small to carry enough dV for a standalone mission, and too heavy to use for a simple reentry vehicle for BEO missions. Its design is constrained by the Constellation mission profile: 21 days and enough dV for a TEI burn, both of which are useless in Orion's current envisione role. Even the CM is both too small for long duration flights and too big to be a simple reentry capsule. For any meaningful mission, Orion needs an EUS and a hab module. Orion would have been better off either with an ACES or EUS-based service module or a simple cut-down SM like the one fitted to CST-100.

Actually, CST-100 would probably be a better match for Orion's exploration role than Orion. Attach a hab module to a refuelable ACES-based EUS-SM and you have a reusable space-only exploration vehicle. Send crew to dock with a CST-100 and you can go anywhere in the solar system.

Edited October 12, 2017 by Nibb31