Author Topic: 1, 1.5, 2, or 2.5 launch architecture as it applies to SDHLV(or other) NASA HLV  (Read 31110 times)

Offline alexw

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One thing I've been wondering, and I'm sure it's been discussed before:
What about in-orbit rendezvous with a full Delta IV upper stage (launched on the latest Delta IV Heavy) and an Orion? Couldn't that get you to EML1/2 and back?
    I don't think so, for three reasons:
     DIRECT looked at this. A DIVHUS will just barely push a 22mT fueled Orion through TLI. EML 1 & 2 are delta-v-i-er.
     You also couldn't do rendezvous with the DIVHUS, unless you're amazingly quick, because the loiter time in LEO is quite low; even the GSO kit only gives, what, 6 hours?
     Also, you can't quite lift a second, full DIVHUS on a DIVH, perhaps not even with RS-68A; it masses about 30mT (though adding GEMs would do it.)
     We need a better upper stage!
     -Alex

Offline mmeijeri

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    I don't think so, for three reasons:
     DIRECT looked at this. A DIVHUS will just barely push a 22mT fueled Orion through TLI. EML 1 & 2 are delta-v-i-er.

You can if you let Orion do the insertion burn. You don't need the full Orion fuel load for L1/L2 insertion and deorbit.

Quote
You also couldn't do rendezvous with the DIVHUS, unless you're amazingly quick, because the loiter time in LEO is quite low; even the GSO kit only gives, what, 6 hours?

You would need some modifications if you want to do EOR.

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Also, you can't quite lift a second, full DIVHUS on a DIVH, perhaps not even with RS-68A; it masses about 30mT (though adding GEMs would do it.)
     -Alex

Not a problem on an SDLV.

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We need a better upper stage!

Or a smaller Orion.
Pro-tip: you don't have to be a jerk if someone doesn't agree with your theories

Offline alexw

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Hmmm, possibly. Something like 0.6 km/s more uphill, 0.7 km/s downhill, plus some gravity losses. If you had the Orion with 1.8 km/s delta-v it should work, a little close with the 1.5 km/s budgeted for the CTV.
  The OP was asking about launch on a DIV-H.
   I think you'd need quite a lot of modifications to do EOR!
    -Alex

Offline mmeijeri

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  The OP was asking about launch on a DIV-H.
   I think you'd need quite a lot of modifications to do EOR!

I agree and that is one of the most important things I'd like to see money spent on after a spacecraft. If this is almost as expensive as the ACES upper stage, then that should probably be done instead, giving us a smallish HLV in the process, which would be easily capable of lifting an EDS bigger than DCSS. But given what ULA has been saying about upper stage improvements I get the impression that an EDS kit for Centaur or DCSS would be an incremental step in that direction.

No need for a big first stage though...
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Offline MP99

Correction:  reverse the order of the launches...  sorry...

A JUS is supposed to have 0.01% per day passive boiloff.
Is that feasible? It seems obvious that it is a requirement.

How fast could you cycle the launch pad? A month?

Would a launch-on-need capability be required/desired?

The DIRECT guys used 0.35% per day boiloff in their Moon mission sims (just so it matched AVUS / CxP), but they reckoned 0.1% would be easily in reach for JUS. At ~130nmi, 0.01% is below station-keeping requirements (assuming you use boiloff for this), so that's unrealistic.

NB this is why HEFT loiters in an orbit over 200nmi, it trades dV to reach / circularise that orbit against station-keeping.

ULA's ACES-based depots also have a different structure than their ACES upper stages & use sunshields to achieve 0.01% passive boiloff, and I'm not even sure they can achieve this in LEO. If you want such a passive architecture, then I believe you must use a depot for long-term storage (or a boiloff-optimised JUS tanker) which would transfer prop to another stage before TxI.


cheers, Martin

Offline MP99

Agree re having a separate thread for this. Here's what I posted in the DIRECT thread before I knew this existing. It makes more sense here:-


I think that both are still possible under the bill. It will be up to NASA to make that decision later on. One of the concern that Augustine had was that commercial companies would have much less business opportunities once the ISS was deorbited. Thus the idea of space taxis.

But the idea of space taxis could still work with SLS (even if it has a crewed version). If a mission can be done with a 1.5 structure (SLS plus commercial crew) instead of a 2.0 structure (SLS Cargo and another SLS with crew), why not use commercial companies for such missions? 


In regards to a 1.5 system relevant to this chain of posts (Taxi system to in orbit SLS components) I have not seen or been part of an analysis so I will reserve judgment.  However, if SLS is to take up the multifunction vehicle it may make sense to put a crew in it.  Unless, the desire is not to human rate SLS.

This chain of post was partially pushed along by me since it was my belief that DIRECT members and others believed the bill required SLS to carry a crew.  If the intent of Congress was to leave open the requirement for whether SLS is to carry a crew or not, then I understand.

Actually, if we're using 1.5 terminology in the same manner as CxP, "1.5" would imply launching Orion on something like an EELV-H, which then docks with the stack.

However, HEFT also differentiated costs for at least three variants of Orion, and found that Orion could be cheaper if it didn't have to carry crew through the ascent.

I'd suggest we retain "1.5" for launching Orion crewed on A.N.other launcher, and name HLV + crew taxi as "1.1" instead of "1.5".

Note that the "0.5" launch in CxP contributed >20mT of the Lunar mission stack. Launching Orion on EELV or EELV-H could also contribute 10-20mT.

A crew taxi might contribute <1mT - just the mass of the crew. Of course, the taxi might carry a little extra mass, but surely not many tons.



I realize that many people use 1.5 in that capacity, I just do not agree with the underlying premise. You are selling yourself short. Was Mercury a 0.5 architecture? Or Gemini?  By using fractional launch terminology, you are implying that any mission without an HLV component is incomplete.
    The 0.5 is especially misleading, since it looks like a 1 sig-fig decimalization of the non-quantitative human language use of "half".

   Going by mass alone, if an F9 or AV-x0x lifts around 10mT, then with the 5/5 vehicle it's a 1.1 launch, for the 4/3 it's a "1.14" launch. The latter is especially nice ;)
   -Alex

I don't think the relevant metric is how much the crew taxi masses, it's how it contributes to the mission stack in orbit.

Baseline:- Orion + crew on HLV.

Uncrewed Orion on HLV+ crew taxi ("1.1"):- HLV launches slightly more due to not needing LAS, taxi delivers negligible BLEO payload. Net IMLEO change: < 5mT?

HLV + Orion on EELV ("1.5"):- HLV launches slightly more due to not needing LAS, plus Orion is docked into BLEO stack.  Net IMLEO change: +15-25mT?

NB this assumes same margins on an uncrewed HLV flight as on a crewed one.

cheers, Martin

Offline Robotbeat

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MP99:
Delta IV Heavy with RS-68A (which is a given at this point) can put about 30 metric tons into an ISS orbit. That's much greater than Ares I.

Just thought I'd mention that.
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Offline marsavian

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27-28mT as opposed to 26mT for Ares I. Not much greater.
« Last Edit: 10/06/2010 06:23 pm by marsavian »

Offline Robotbeat

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27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline marsavian

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27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.

The penalty for that is about the same as Delta IV having to follow a human rated 4g ascent profile so the relative performance difference is still the same i.e less than 10%.

Offline Robotbeat

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27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.

The penalty for that is about the same as Delta IV having to follow a human rated 4g ascent profile so the relative performance difference is still the same i.e less than 10%.

Show me.
EDIT:My main point is that MP99 originally had implied (probably not intentionally) that Ares I would give greater performance than Delta IV Heavy, when the opposite is true.
« Last Edit: 10/06/2010 06:41 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline 93143

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A JUS is supposed to have 0.01% per day passive boiloff.

The DIRECT guys used 0.35% per day boiloff in their Moon mission sims (just so it matched AVUS / CxP), but they reckoned 0.1% would be easily in reach for JUS. At ~130nmi, 0.01% is below station-keeping requirements (assuming you use boiloff for this), so that's unrealistic.

...

ULA's ACES-based depots also have a different structure than their ACES upper stages & use sunshields to achieve 0.01% passive boiloff, and I'm not even sure they can achieve this in LEO.

Okay, the comments from the DIRECT team have been confusing at times.

The JUS has a common bulkhead and is based on the WBC "Cold Technology". It has a passive boiloff rate of 0.01%. Active boiloff is significantly less than that. It is specifically designed for long-duration loiter.

WBC would essentially bring all the tanking technologies together in one unit to make a 0.1% boiloff stage.   ICES then takes that excellent foundation and adds a few more specific features (like the VDMLI and vapor cooling) to improve the passive boiloff characteristics to the point where you really don't need any active cooling unless you're planning to hold the same fuel in one tank, without re-filling, for a period measured in years.

On the other hand, there's this:

As for boiloff, we have more than enough margin built in for that. We've been publicizing the NASA rate at 0.35% per day, and that's the number used in the performance calculations, but in reality because of the JUS design it's 0.10% for the passive system, and when the active system becomes operational it'll be more like 0.01% per day.

which says what you just did.

Hmm...

Either way, it's pretty good, so prompt rendezvous is not mission-critical.

Offline Robotbeat

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What is "prompt-rendezvous?"

WBC doesn't exist (yet). Can its low boil-off be assumed for the architecture before it's demonstrated?

PS, I have no doubt low-boiloff is possible, but if we don't have the money or time to develop the technology for it... well...
« Last Edit: 10/06/2010 07:00 pm by Robotbeat »
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Offline marsavian

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27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.

The penalty for that is about the same as Delta IV having to follow a human rated 4g ascent profile so the relative performance difference is still the same i.e less than 10%.

Show me.
EDIT:My main point is that MP99 originally had implied (probably not intentionally) that Ares I would give greater performance than Delta IV Heavy, when the opposite is true.

Actually it does if you bother to human rate it to the same accepted standard as Ares I as Aerospace did in their study.

http://www.nasa.gov/pdf/377875main_081109%20Human%20Rated%20Delta%20IV.pdf

p.30 (p17 in pdf)

To ISS target
---------------

  (config 1) RS-68A D-IVH -> 25.8mT 
  (config 6) human-rated D-IVH  -> 18.3-23.6mT
                 depending on whether you use the correct 75% human rating of RL10-A-4-2 or use it at 100% which is            not strictly human rated.
                 Ares I  -> 23.1mT


To Lunar target
-----------------

  (config 1) RS-68A D-IVH -> 27.5mT 
  (config 6) human-rated D-IVH  -> 20.4-25.3mT
                 depending on whether you use the correct 75% human rating of RL10-A-4-2 or use it at 100% which is            not strictly human rated.
                 Ares I  -> 25.5mT
« Last Edit: 10/06/2010 07:32 pm by marsavian »

Offline Robotbeat

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27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.

The penalty for that is about the same as Delta IV having to follow a human rated 4g ascent profile so the relative performance difference is still the same i.e less than 10%.

Show me.
EDIT:My main point is that MP99 originally had implied (probably not intentionally) that Ares I would give greater performance than Delta IV Heavy, when the opposite is true.

Actually it does if you bother to human rate it to the same accepted standard as Ares I as Aerospace did in their study.

http://www.nasa.gov/pdf/377875main_081109%20Human%20Rated%20Delta%20IV.pdf

p.30 (p17 in pdf)

To ISS target
---------------

  (config 1) RS-68A D-IVH -> 25.8mT 
  (config 6) human-rated D-IVH  -> 18.3-23.6mT
                 depending on whether you use the correct 75% human rating of RL10-A-4-2 or use it at 100% which is            not strictly human rated.
                 Ares I  -> 23.1mT


To Lunar target
-----------------

  (config 1) RS-68A D-IVH -> 27.5mT 
  (config 6) human-rated D-IVH  -> 20.4-25.3mT
                 depending on whether you use the correct 75% human rating of RL10-A-4-2 or use it at 100% which is            not strictly human rated.
                 Ares I  -> 25.5mT

While I may dispute parts of that, I want to say: Thank you! I really appreciate it when people back up their opinions with numbers and reviewed analysis. :D
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Offline alexw

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Actually it does if you bother to human rate it to the same accepted standard as Ares I as Aerospace did in their study.
http://www.nasa.gov/pdf/377875main_081109%20Human%20Rated%20Delta%20IV.pdf
  (config 1) RS-68A D-IVH -> 25.8mT 
  (config 6) human-rated D-IVH  -> 18.3-23.6mT
                 depending on whether you use the correct 75% human rating of RL10-A-4-2 or use it at 100% which is            not strictly human rated.
                 Ares I  -> 23.1mT
     All DIV are moving to RS-68A; RS-68B (options 2-6) is unlikely to exist without Ares V.
    Present DIVH use RL-10-B2. NASA would seem unlikely to have DIVHUS specially built with RL-10A. It also seems not terribly likely that NASA would use DIVH to launch manned Orions, rather than Commercial Crew or on SLS, but if NASA were to choose to do so it might well be in the context of some form of Common Upper Stage. Which would then use the newer RL-10C (or whatever it is called), because that same engine variant would also be used for the CPS (or whatever it is called) -- we're going to have to build a modern RL-10 one way or the other. The Option 6 vehicle you refer to above is, of course, extremely under-thrusted with a 75% thrust-reduced -10A instead of a 100% -10B, giving poor performance.
    Option 4 is more of a Common Upper Stage / ACES / Phase I vehicle; 29mT in this study (assuming low-thrust). If the -10C is instead human-rated for more like the 100% -10B thrust levels, then the DIVH-Phase I puts about 40mT to LEO, reduce that a little for ISS.
   You could, of course, imagine a scenario where the newer RL-10 was used but as an upgrade in the older DCSS/DIVHUS. That might put its performance closer to Option 1.
    -Alex

Correction: whoops, RS-68B (in this case) would be a straightforward  (and necessary) human-rating of -A, not the regen nozzle engine. Lousy overloaded nomenclature.
« Last Edit: 10/06/2010 08:07 pm by alexw »

Offline marsavian

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While I may dispute parts of that, I want to say: Thank you! I really appreciate it when people back up their opinions with numbers and reviewed analysis. :D

Of course those figures assume a J-2X which is delivered to Isp spec and TO mitigation that doesn't bust the current margins. What's clear is that they are in the same ballpark and D-IVH would be a worthy Ares I substitute for any 0.5 launches further down the line in conjunction with SLS. If Orion is ready before Commercial and SLS and Soyuz was grounded it could even be used in an ISS emergency because even the current D-IVH is safer than Shuttle when allied to an Orion with LAS.
« Last Edit: 10/06/2010 08:05 pm by marsavian »

Offline MP99

27-28mT as opposed to 26mT for Ares I. Not much greater.
Make sure to compare apples to apples... With Ares I, the trajectory is suborbital.

The penalty for that is about the same as Delta IV having to follow a human rated 4g ascent profile so the relative performance difference is still the same i.e less than 10%.

Show me.

EDIT:My main point is that MP99 originally had implied (probably not intentionally) that Ares I would give greater performance than Delta IV Heavy, when the opposite is true.

It's worth bearing in mind that Mars DRA 5.0 has a ~15mT Orion, including a minimal SM, thoughh whether that's sufficient for launch & rendezvous...? The ISS- or Lunar-spec Orions might have a role in some missions?

But remember that HEFT is assembling the mission stack at 220nmi circular, not 130nmi like CxP. Can an HR'd DIVH lift 22mT to 220nmi circ without an SM burn?



1) Baseline:- Orion + crew on HLV.

2) Uncrewed Orion on HLV+ crew taxi ("1.1"):- HLV launches slightly more due to not needing LAS, taxi delivers negligible BLEO payload. Net IMLEO change: < 5mT?

3) HLV + Orion on EELV ("1.5"):- HLV launches slightly more due to not needing LAS, plus Orion is docked into BLEO stack.  Net IMLEO change: +15-25mT?

Just fleshing this out:-

For (2), the HLV will lift maybe 2-3mT more than (1) - no LAS, but PLF retained to orbit. Add 1-2mT of mass from the taxi?

For (3), the HLV will lift maybe 5-6mT more than (1) - PLF is also discarded during ascent - see J-246 CaLV vs CLV. Add an ~18mT ISS-spec Orion for ~24mT contributed to the IMLEO.

Or add a Lunar-spec Orion, of course.

cheers, Martin

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