Orion BEO before SLS

[sdsds]

I suspect that this has been talked about elsewhere, but I couldn't find an in depth discussion of it, so I apologize in advance if this thread is redundant.

Since Orion will be ready before SLS, and since DIVH is unlikely to become manrated in the foreseeable future, what about a mission profile such as this to perform manned BEO flights before the second SLS flight, which seems to be planned for NET 2019

-Launch Commercial crew to ISS
-Launch Orion to ISS on DeltaIVH
-Launch Modified Centaur with NDS docking ring to near ISS
-Crew transfer to Orion
-Orion departs ISS and rendezvous with Centaur
-Centaur does eyeballs-out TLI

Aside from politics, what reasons would prevent such a mission if the powers that be wanted an early manned mission to Lunar orbit?

Ignoring the politics as you request, the reasons that would prevent such a mission are all related to cost.

Yes, you could launch Orion to ISS, but the cost of certifying it as a visiting vehicle would be borne entirely by this effort, as that is not the plan for Orion.  Yes, you could launch a modified Centaur on a DIV-H, but DIV-H has never carried a cryogenic payload, so your program would bear the entire cost of modifying the DIV-H ground systems to accommodate that kind of payload.  Then having Centaur ride as a payload might require more than merely a standard kit modification.

[Sparky]

Ignoring the politics as you request, the reasons that would prevent such a mission are all related to cost.

Yes, you could launch Orion to ISS, but the cost of certifying it as a visiting vehicle would be borne entirely by this effort, as that is not the plan for Orion.  Yes, you could launch a modified Centaur on a DIV-H, but DIV-H has never carried a cryogenic payload, so your program would bear the entire cost of modifying the DIV-H ground systems to accommodate that kind of payload.  Then having Centaur ride as a payload might require more than merely a standard kit modification.

I was (possibly eroneously) assuming that Orion was still being planned as a lifeboat for ISS.

And why would you want a Centaur on DIVH? Aside from the fact that Atlas already carries it, there is only one launchpad at the cape for Delta IV. Rather than bottleneck work by having to stack one vehicle after another in series, it would probably be much easier to set them up in parallel on different vehicles.

[mmeijeri]

And why would you want a Centaur on DIVH?

It could be an Atlas Heavy too, but using a single Centaur second stage might not do the trick. The idea is to use the Centaur as a payload for an EELV Heavy, or as a sort of third stage if you prefer to look at it that way. A fully loaded Centaur is too heavy for a single core EELV. Actually, I believe Orion is slightly too heavy for a Centaur on a fast trajectory as you would use for manned missions, but it's been a while since I last did the sums. It would be more than enough for a Dragon-sized capsule.

[mmeijeri]

Yes, you could launch a modified Centaur on a DIV-H, but DIV-H has never carried a cryogenic payload, so your program would bear the entire cost of modifying the DIV-H ground systems to accommodate that kind of payload.

That's not a bad choice if you intend to make this the standard way to go beyond LEO, which would itself be an excellent choice. And that brings us back to politics, not costs per se. There's no way the pro-SLS politicians will want to allow that to happen. A successful EELV / Falcon based flight beyond LEO would be a major embarrassment.

Then having Centaur ride as a payload might require more than merely a standard kit modification.

I'm curious about that. It might be easy as the vehicle already knows how to handle a single Centaur.

[Sparky]

And why would you want a Centaur on DIVH?

It could be an Atlas Heavy too, but using a single Centaur second stage might not do the trick. The idea is to use the Centaur as a payload for an EELV Heavy, or as a sort of third stage if you prefer to look at it that way. A fully loaded Centaur is too heavy for a single core EELV. Actually, I believe Orion is slightly too heavy for a Centaur on a fast trajectory as you would use for manned missions, but it's been a while since I last did the sums. It would be more than enough for a Dragon-sized capsule.

That's a good point.

Okay, so since EFT-1 is going to use a DIVUS to send an Orion to a high orbit, would it be reasonable to assume that a similar stack could reach LEO with delta-v to spare? Possibly enough to make up the difference?

The biggest problem I see with that is I am not sure that the ISS partners would be okay with docking an Orion attached to a fueled DIVUS to the station.

[mmeijeri]

Okay, so since EFT-1 is going to use a DIVUS to send an Orion to a high orbit, would it be reasonable to assume that a similar stack could reach LEO with delta-v to spare? Possibly enough to make up the difference?

Do you mean an SLS with an EELV upper stage? With DCSS that would definitely work, unless Orion has become heavier since I last did the sums. Not all the way to LLO and back, but to L1/L2 and back would work and that's all you need.

The biggest problem I see with that is I am not sure that the ISS partners would be okay with docking an Orion attached to a fueled DIVUS to the station.

If you are going to use SLS you can do it all in one launch, ISS wouldn't be needed. If you are going to use the ISS then Orion would arrive first, without an EELV upper stage attached to it. It could then rendez-vous with an EELV upper stage 100 km or so away from the ISS, which should be fine.

[spectre9]

Even after EFT1 in 2014 there's a long way to go before Orion can carry a crew.

I don't think it's possible that one will be ready before the other so there's not much point in trying to build missions for the Orion without SLS.

[mmeijeri]

That could change if SLS were to die... I think you'll then suddenly see a lot of interest in such missions from Orion / JSC circles. But by then Dragon may already have performed such a feat, in which case it would be too late. Just saying.

[Sparky]

Okay, so since EFT-1 is going to use a DIVUS to send an Orion to a high orbit, would it be reasonable to assume that a similar stack could reach LEO with delta-v to spare? Possibly enough to make up the difference?

Do you mean an SLS with an EELV upper stage? With DCSS that would definitely work, unless Orion has become heavier since I last did the sums. Not all the way to LLO and back, but to L1/L2 and back would work and that's all you need.

No, I meant a Delta IV Upper Stage, (which unless I am horribly confused, is also being put on SLS) as launched on a Delta IV Heavy.

From what I understand of EFT-1, the upper stage remains attached to the Orion MPCV until just prior to entry.

Here are my assumptions:

1)I assume that most of the propellant in the upper stage of EFT-1 will have been expended to reach this high elliptical orbit that it is planned to make.

2)I assume that sending the same type of vehicle, (Delta IV Heavy), but launched to LEO, might use less propellant, and have enough left over to add to what the Centaur would provide.

I admit I may be completely off base with this, but that's why I'm putting it out there.

Also, I must admit that until just now I had confused a Centaur used as an upper stage with a Centaur as a payload. For some reason I assumed that an AtlasV alone could launch a Centaur into orbit. Indeed, AVH or DIVH would be needed.

[Jorge]

Ignoring the politics as you request, the reasons that would prevent such a mission are all related to cost.

Yes, you could launch Orion to ISS, but the cost of certifying it as a visiting vehicle would be borne entirely by this effort, as that is not the plan for Orion.

I was (possibly eroneously) assuming that Orion was still being planned as a lifeboat for ISS.

The law specifies that Commercial Crew will provide the ISS lifeboat function, and that Orion will be the backup in case Commercial Crew is not available. Therefore Orion must be certified as an ISS visiting vehicle anyway, even independent of this BEO plan, but it is not planned as the primary vehicle for ISS crew rotation or lifeboat.

[Lars_J]

Because ISS is in the wrong orbit for lunar transfer?  You could get there but it would be a lot of extra fuel.

This is a myth. The problems would be political, not technical.

Lunar launch windows would be far fewer in an ISS orbit, otherwise it is not a terrible staging point per se.

[Proponent]

Okay,  so since EFT-1 is going to use a DIVUS to send an Orion to a high  orbit, would it be reasonable to assume that a similar stack could reach  LEO with delta-v to spare? Possibly enough to make up the difference?

Do you mean an SLS with an EELV upper stage? With DCSS that would  definitely work, unless Orion has become heavier since I last did the sums. Not all the way to LLO and back, but to L1/L2 and back would work and that's all you need.

[CORRECTION]
I just ran some quick numbers (attached; tried to attach original LibreOffice spreadsheet, but forum software doesn't allow it).  L1 does appear possible with the 5-m version of the Delta IV upper stage, though not with the Centaur.

Centaur figures are taken from the Atlas V User's Guide, available on ULA's website.  Orion figures come from NASA Facts (attached; I can't believe these guys would publish figures in Imperial units only -- do they think it's the 1960s?).  Delta-Vs for the L1 mission come from the attached 1969 paper about Apollo missions to L-points.

[pathfinder_01]

Because ISS is in the wrong orbit for lunar transfer?  You could get there but it would be a lot of extra fuel.

This is a myth. The problems would be political, not technical.

Lunar launch windows would be far fewer in an ISS orbit, otherwise it is not a terrible staging point per se.

Launch windows to l1/l2 open up every ten days or so from the ISS.

http://history.nasa.gov/DPT/Architectures/Moon%20-%20L1-Moon%20Exploration%20Architecture%20DPT%20Jun_00.pdf

[SpacexULA]

Because ISS is in the wrong orbit for lunar transfer?  You could get there but it would be a lot of extra fuel.

This is a myth. The problems would be political, not technical.

Lunar launch windows would be far fewer in an ISS orbit, otherwise it is not a terrible staging point per se.

Launch windows to l1/l2 open up every ten days or so from the ISS.

http://history.nasa.gov/DPT/Architectures/Moon%20-%20L1-Moon%20Exploration%20Architecture%20DPT%20Jun_00.pdf

Thanks you, my foot now resides firmly in my mouth.

[pathfinder_01]

From what I understand of EFT-1, the upper stage remains attached to the Orion MPCV until just prior to entry.

Here are my assumptions:

1)I assume that most of the propellant in the upper stage of EFT-1 will have been expended to reach this high elliptical orbit that it is planned to make.

2)I assume that sending the same type of vehicle, (Delta IV Heavy), but launched to LEO, might use less propellant, and have enough left over to add to what the Centaur would provide.

I admit I may be completely off base with this, but that's why I'm putting it out there.

Also, I must admit that until just now I had confused a Centaur used as an upper stage with a Centaur as a payload. For some reason I assumed that an AtlasV alone could launch a Centaur into orbit. Indeed, AVH or DIVH would be needed.

The EFT-1 will not have the standard service module. Orion would be battery powered, lack it's own engine and only last a few hours.  Orion would need it's lunar service module for a L1 mission.

The way it could work is Orion launched unmanned via Atlas or Delta to the ISS. With out the LES Orion might be launchable on the cheaper Atlas.  Orion could be launched months before the crew if needed.

Crew launched on commercial crew craft. All CCDEV craft hold a crew of 7.  That is enough to rotate the station crew and provide the crew for Orion in 1 launch(3-4 for the ISS and 3-4 for Orion). The station can support a surge crew of 14 if need be.  The only modifiation to the ISS might be to add an visting craft module to support extra doking ports and extra storage.

The EDS launched on Delta Heavy. This could push Orion to L1. If the EDS is unable to be launched then the lunar crew could either return home via commercail crew with the out going crew or via Orion.  If they return via commercail crew it might be possibe to try again on the next ISS crew rotation. Orion was supposed to be able to support itself for 6 months (docked or undocked at a station) and a crew of 4 for 21 days.

[Sparky]

So it seems that people agree that this is a sound idea in principle, which would allow NASA to launch multiple manned circum-lunar missions within the decade, using existing hardware at a fraction of the cost of SLS?

[pathfinder_01]

So it seems that people agree that this is a sound idea in principle, which would allow NASA to launch multiple manned circum-lunar missions within the decade, using existing hardware at a fraction of the cost of SLS?

Yeap, the political problem is if you use Delta for a launcher you are not using the shuttle workforce.  Anyway in 2008 ULA offered Delta Heavy to NASA for a one time cost of 1 billion(or so) to man rate and 300 million a flight if NASA purchased 9 flights.

In addition you really need some hardware at l1/l2 to make this mission more useful than 3 guys in a can for 21 days. A station (and there are plans that use SEP to move a station from LEO(ISS) to l1/l2. A lunar lander and you might need some supply craft(Dragon could be the easist to modify into a BEO supply craft launched on a FH).

[Archibald]

I tried to push that idea of ISS / staging point a bit further in this thread, and learned a lot of interesting details in the process.
http://forum.nasaspaceflight.com/index.php?topic=25490.30

[mmeijeri]

If the EDS is unable to be launched then the lunar crew could either return home via commercail crew with the out going crew or via Orion.  If they return via commercail crew it might be possibe to try again on the next ISS crew rotation. Orion was supposed to be able to support itself for 6 months (docked or undocked at a station) and a crew of 4 for 21 days.

Or they could be put on KP duty for a couple of weeks. Requires some special planning obviously.

[mmeijeri]

So it seems that people agree that this is a sound idea in principle, which would allow NASA to launch multiple manned circum-lunar missions within the decade, using existing hardware at a fraction of the cost of SLS?

Yes, and if you spent the Orion and SLS money on a lander and a service module instead, you could start doing lunar missions too.