NASA SLS/Orion/Payloads

[Jacke]

3 hours ago, YNM said:

Diameter of FH : 3.66 m.

Diameter of FH/F9 fairing : 5.2 m, height 13 m, roughly cylindrical.

Diameter of Orion CM : 5.02 m, height 3.3 m + LES, fully conical.

You're not going to get away with flying a pancake on top of a pencil.

It's called hammerheading, puttting a wider payload on a launch vehicle.  It's been done before.  Would need a custom interstage and fairing.

But FH may not be able to handle the Lunar missions for Orion.

 

[NSEP]

33 minutes ago, Jacke said:

But FH may not be able to handle the Lunar missions for Orion.

It can, but it has to use the fuel if the Orion SM to kick it into a higher orbit, which means it doesn't have enough fuel to get into orbit, but EM1 and EM2 don't need to do that anyways.

I already posted it in the SpaceX thread, but i tried it in Kerbal Space Program (Realism Overhaul of course)

As you can see here it has around 12.8km/s of Delta-V, which is enough for a circumlunar mission. You need around 12.7km/s (9.5 for orbit and 3.2 for TLI burn) to go to the Moon so we have 100m/s left.

 

[YNM]

3 hours ago, sh1pman said:

 

3 hours ago, Jacke said:

It's called hammerheading, puttting a wider payload on a launch vehicle. It's been done before.

AKA they still need to design an actual interstage for the whole thing - that's more aerodynamic test, more design, more time, more funds, etc etc.

Delta IV Heavy have a fairing already suited for it.

[Canopus]

Integrating Orion and FH would probably take longer and be more expensive that just sticking with SLS and launch half a year or something later. I‘m sure Orion will survive SLS and eventually launch on another Rocket but right now this is nothing but a play to appease the Commercial launcher fans.

[MinimumSky5]

Somehow, I doubt that SLS will only be delayed by half a year. Even if it isn't, and somehow the program accelerates to the point the SLS does in fact launch next year, the core stage is horribly oversized for its upper stage until the EUS gets funded, so switching to a commercial launcher is just generally a better idea. 

[Canopus]

18 minutes ago, MinimumSky5 said:

Somehow, I doubt that SLS will only be delayed by half a year. Even if it isn't, and somehow the program accelerates to the point the SLS does in fact launch next year, the core stage is horribly oversized for its upper stage until the EUS gets funded, so switching to a commercial launcher is just generally a better idea. 

How would switching to Commercial launchers for EM-1 EM-2 solve the EUS delay? 

[DDE]

1 hour ago, Canopus said:

Integrating Orion and FH would probably take longer and be more expensive that just sticking with SLS and launch half a year or something later. I‘m sure Orion will survive SLS and eventually launch on another Rocket but right now this is nothing but a play to appease the Commercial launcher fans.

I’m not terribly sure. It’s not very much unlike the SLS in its nature - suited for specific, rather exotic missions, but also very conservative and limited in its capabilities.

7 minutes ago, Canopus said:

How would switching to Commercial launchers for EM-1 EM-2 solve the EUS delay? 

It will at best mitigate it.

Edited March 16, 2019 by DDE

[Canopus]

Just now, DDE said:

I’m not terribly sure. It’s not very much unlike the SLS in its nature - suited for specific, rather exotic missions.

Missions beyond LEO? Once distributed launch is demonstrated and practiced by ULA and maybe Blue Origin i could imagine them to ditch SLS for New Glenn or Vulcan. 

[DDE]

3 hours ago, Canopus said:

Missions beyond LEO?

While lacking dV to return from low Lunar orbit, or the heat shield to survive a Mars return? That’s an extremely narrow niche.

[Ultimate Steve]

1 minute ago, DDE said:

While lacking dV to return from low Lunar orbit, or the heat shield to survive a Mars return? That’s an extremely narrow niche.

To be fair, most space capsules are extremely niche as well, and most space stuff in general.

[Canopus]

15 minutes ago, DDE said:

While lacking dV to return from low Lunar orbit, or the heat shield to survive a Mars return? That’s an extremely narrow niche.

Whats this Forums Obsession with Low Lunar Orbits? And even if you would absolutely need it to go to LLO you probably could with ACES or something like that. And i never heard anything about Mars return being impossible, got any Scource for that? (Not that it would matter much since any Mars mission is decades away and might not even use a direct return anyway) 

[DDE]

3 minutes ago, Canopus said:

And i never heard anything about Mars return being impossible, got any Scource for that? (Not that it would matter much since any Mars mission is decades away and might not even use a direct return anyway) 

Not sure what source, but Orion's AVCOAT heat shield is optimized for Lunar entry... whether the Dragon is so overengineered it's apparently already good enough for Mars return. However, there's been a major upgrade since EM-1, ad me hanging out with Musketeers take away quite a bit of credence from that claim.

Besides, I'm not sure why anyone would carry around an SM when Orion is being used as part of a major mission vehicle.

4 minutes ago, Canopus said:

Whats this Forums Obsession with Low Lunar Orbits?

I dunno, perchance because it rules out simple and straightforward recreations of Apollo?

[Canopus]

6 minutes ago, DDE said:

Besides, I'm not sure why anyone would carry around an SM when Orion is being used as part of a major mission vehicle.

I dunno, perchance because it rules out simple and straightforward recreations of Apollo?

Yeah feels like: „Apollo went to LLO so all lunar missions have to go there“.

You might want to carry the SM for some limited abort scenarios or leave CM and SM behind and stage from high earth or lunar orbits, DST style. Still i think any credible Mars mission is so far off that it probably isn‘t worth speculating too much.

[tater]

23 hours ago, Canopus said:

Whats this Forums Obsession with Low Lunar Orbits? And even if you would absolutely need it to go to LLO you probably could with ACES or something like that. And i never heard anything about Mars return being impossible, got any Scource for that? (Not that it would matter much since any Mars mission is decades away and might not even use a direct return anyway) 

The current goal is supposedly a base on the surface. That means going to LLO at some point.

Whts the point of a high lunar orbit, exactly? Is it to maximize astronaut radiation exposure?

[Barzon]

That, @tater is hilarous! "Maximise astronaut radiation exposure." pure comedy gold! 

[sh1pman]

34 minutes ago, tater said:

Whts the point of a high lunar orbit, exactly? Is it to maximize astronaut radiation exposure?

It’s because Orion can’t make a round trip to low lunar orbit. Also, direct communications possible most of the time.

[StrandedonEarth]

Also more stable than LLO, AFAIK

[tater]

16 hours ago, sh1pman said:

It’s because Orion can’t make a round trip to low lunar orbit. Also, direct communications possible most of the time.

 

16 hours ago, StrandedonEarth said:

Also more stable than LLO, AFAIK

All three of these are correct, but the first is the primary reason. When you have lemons, make lemonade. NRO, NRHO, etc are orbits Orion can do with SLS, hence they were chosen. Direct comms is a bizarre requirement, all they need is to put a couple sats around the Moon, and that ceases to become an issue. Stability is a real concern, and one thing to add to that would be station-keeping requirements, since it will necessarily be visited less often than ISS is.

The alternative would be to pick a mission, then choose the best possible orbit, then build that system. That's not what SLS is, nothing about it is optimal for anything. In fact, that's my big issue with the whole thing. It's been incredibly expensive to develop, and it will be incredibly expensive to fly, so you'd think it would do, you know, something well/best.

Edited March 18, 2019 by tater

[tater]

On 3/16/2019 at 10:56 AM, Canopus said:

Integrating Orion and FH would probably take longer and be more expensive that just sticking with SLS and launch half a year or something later. I‘m sure Orion will survive SLS and eventually launch on another Rocket but right now this is nothing but a play to appease the Commercial launcher fans.

The NASA Administrator has zero incentive to "appease the commercial launcher fans." This is more likely about Pence wanting to see something fly in the (pre-Nov) 2020 timeline.

 

[Canopus]

On 3/14/2019 at 9:17 AM, Canopus said:

Yeah this isn't going to happen, someone is desperate to launch EM-1 while he is still president.

 

39 minutes ago, tater said:

The NASA Administrator has zero incentive to "appease the commercial launcher fans." This is more likely about Pence wanting to see something fly in the (pre-Nov) 2020 timeline.

 

atleast something we agree on.

16 hours ago, tater said:

The current goal is supposedly a base on the surface. That means going to LLO at some point.

Whts the point of a high lunar orbit, exactly? Is it to maximize astronaut radiation exposure?

Orion will never be in LLO, only the Lander. 

LLO is harder for station keeping (Leaving your capsule in orbit during long missions) Harder on Thermal systems, in case of a polar orbit, access from the  surface to an Orbiting vehicle is also limited during long a surface stay. The only radiation advantage is that in LLO a big part of the Sky is covered by the moon as a radiation shield.

Future stations and propellant depots won't be in LLO so why not have Landers now that are already up to the task, of Landing from and returning to a higher more stable Orbit?

16 hours ago, Barzon Kerman said:

That, @tater is hilarous! "Maximise astronaut radiation exposure." pure comedy gold! 

Musk is already working on that with Starship.

[tater]

1 hour ago, Canopus said:

Orion will never be in LLO, only the Lander. 

That's because it has a lousy SM, and nothing about the system was designed to go, well, anywhere useful.

Constellation had 2 missions. Return to the Moon, and building a Mars architecture (human).

The throw weight to LEO (cargo only!) was well above Apollo, and crew would never be comanifested, so that's all stuff in addition to Orion. 188 tonnes, not counting the Orion launch. You can go to the Moon as needed. You can send a prop depot to an L point (or NRHO, whatever). You can build a Mars craft.

SLS will never make any sense at all. Block 2 would be heading in the right direction (140 tonnes cargo only), except that they would HAVE to move Orion to a commercial LV anyway, as they will NEVER fly SLS a couple times a few days apart (or even a few weeks apart). Not ever. With massive increases in money they might someday be able to fly twice in a year, months apart, maybe. In a fantasy world.

 

1 hour ago, Canopus said:

LLO is harder for station keeping (Leaving your capsule in orbit during long missions) Harder on Thermal systems, in case of a polar orbit, access from the  surface to an Orbiting vehicle is also limited during long a surface stay. The only radiation advantage is that in LLO a big part of the Sky is covered by the moon as a radiation shield.

Frozen orbits address the stability issue, but the rest is certainly true. Covering nearly half the sky with a rock is a non-trivial radiation mitigation scheme.

1 hour ago, Canopus said:

Future stations and propellant depots won't be in LLO so why not have Landers now that are already up to the task, of Landing from and returning to a higher more stable Orbit?

This is sensible, but designing any architecture around SLS is stupid. If the goal is a prop depot, build a prop depot from the start, and eliminate SLS entirely, spend the money on what is then needed, a tug (ACES, for example).

 

[tater]

 

 

[tater]

 

[RCgothic]

Does an all up test fire require expending two side boosters? If they don't then the thermal and vibrational environment isn't being tested.

[tater]

3 hours ago, RCgothic said:

Does an all up test fire require expending two side boosters? If they don't then the thermal and vibrational environment isn't being tested.

Pretty sure it was just the core with the 4 RS-25s.