[dougkeenan]

Here is a Jupiter-130 on the pad (next to a 10m segmented stick). The fourth SSME can be switched in by CONFIG file, as can the payload (in this case, an ISS module). Graciously francisdrake has granted the use of his fantastic CEV Orion, found at this thread.

I'm not at all clear on the LAS/fairing jettison order. Right now the LAS automatically jettisons 10 seconds after SRB separation. The fairings stay attached until MECO - so far they're the only thing holding the CEV in place during launch? Doesn't seem right.

The guidance system works ... barely. Keep your finger on the jettison button! A few more tweaks and the beta will be ready for breaking.

[Chupacabra]

From pg 49 of the Direct Launcher Proposal:

For an ascent to the ISS's orbit with the Jupiter-120:
-SRB Separation is at T+124 seconds (35.8nmi; Mach 4.21)
-LAS Jettison is at T+305 seconds (96.3nmi; Mach 10.7)
-MECO/Payload Launch Fairing (PLF)/Payload Deploy is at T+447 seconds at an altitude of 100nmi.

These numbers are slightly outdated by a couple of years but they change slightly with the launch profile anyway. I don't know where the numbers exist for the Jupiter-130 but if anything they will be scaled to an earlier time.

Best of luck

[dougkeenan]

Excellent! Thank you. I do expect some scaling in the numbers and hope to keep up with them.

[simcosmos]

Nice work dougkeenan,

I’m writing this post to make a few quick comments:

• In a way, the 'new' SSME / SSME derived Jupiter launcher configurations (there were also some older configurations in the very DIRECT start that were also powered by SSME, before baselining RS-68 derived engines) are part of an *updated* series of vehicle variants/ studies and are actually something beyond what has been presented on ‘DIRECT v2.0’ paper (I mean, a consequence of the constant work in progress, a result of updated assumptions regarding several constraints: technical, political, workforce and facilities best capabilities skills retention, STS-to-VSE transition, economical sustainability, etc, etc). This to say that as mentioned at nasaspaceflight forums, RS-68 (a regenerative variant) is now then the backup plan.
  
  
• As a side note, I’m also (slowly) preparing an overall update to the really outdated first DIRECT addon version that have released at Orbit Hangar Mods (at that pre-DIRECT v2.0 times the ‘Exploration’ core variant was baselined as been powered by an upgraded regenerative RS-68 variant development) although haven’t yet shared much of the new SSME configurations (and related payloads / spacecraft / launchpad, etc) on my LivePics / Flickr pages (as usual, real life is ‘stealing’ time that once was reserved for Orbiter development…)... But Ross Tierney already shared some of his own imagery about such new configs.
  
  
• In any case, dougkeenan, if you wish public numbers about updated launchers configurations and / or ascent constraints, such info is usually shared (first hand, to the public) somewhere within nasaspaceflight.com forum related DIRECT threads and / or, later on, at DIRECT site / DIRECT ‘official’ materials.

Happy development,
António

[dougkeenan]

Thanks António, for the encouragement and advice. Your comments are most appreciated. I regret my impatience that drove me to develop this model. It was Ross Tierney's new pictures on NSF that fevered my brain, so let's blame him.

Anyway, here's the beta: JUPITER beta 2 (1.21M). The only payload supported is a badly textured ISS module that must be docked, then undocked from the tank. Make sure the tank+CEV gets a KILLROT before jettison!

I'm not trying to be "clean" now so no complaints about the directory structure, or lack thereof. In fact I'd recommend any testing be done in a fresh Orbiter config. The Jupiter DLL looks for the Orion606 config file and uses it if found - if not, it generates a quick vessel and a nag message to upgrade.

Autopilot ('P') is still hitting all over the place, especially with time warp. For now it only tries to match pitch and AOA levels from the posted baseball card, so any user lateral control will not be corrected. Use 'J' for manual staging.

There are two scenarios included for now, a launch and a tank sep. Scenario configs include SSME count (3 or 4), payload (0 or 1), and stage configuration. It has NOT been thoroughly tested for save/restore so expect the unexpected if you try that.

eta: oops there's a name collision, seems "Jupiter" is already something in the solar system. Let me change this rocket to something else. eta2: classname now JUPITERDIRECT, beta updated.

[dougkeenan]

While building the pad it seems the overview view and front view don't quite align (FSS to MLP). Time to tweak the alignment so it looks right.

eta: there's a start on a pad at least: Beta 3

[dougkeenan]

Beta4 (2.41M) Parts are now in place and I need to tune them up.

The EDS (6xRL10) does not seem to have enough oomph to make it to the moon. Either this model is wrong, or my assumption that it performs all the TLI burn. The "ALL RDY" scenario is a few minutes before an attempt at 500x500km if you care to try.

[tblaxland]

Originally Posted by dougkeenan

 The EDS (6xRL10) does not seem to have enough oomph to make it to the moon. Either this model is wrong, or my assumption that it performs all the TLI burn. The "ALL RDY" scenario is a few minutes before an attempt at 500x500km if you care to try.

500x500km is quite a high parking orbit. Instead of launching all the way up to 500x500km, you will get a better result launching to say 200x200km instead and doing your TLI from there due to the Oberth effect. I've attached a small spreadsheet to demonstrate.

That is based on either one of the two assumptions being correct:
1. You are presently using the second stage to get to 500x500km. If this is the case, you will need to get to a 200x200km EPO, then use your remaining second stage fuel at the start of the TLI, followed by the EDS for the rest.; or
2. The second stage gets you to roughly 200x200km and you are currently using the EDS to get to 500x500km. In this case, just do the TLI from 200x200km. (EDIT: This scenario is similar to the Saturn V where the S-IVB was used for the final part of EPO insertion. The later Apollo missions used lower EPOs to extract the maximum benefit from the Oberth effect - 90 NM vs 100 NM)

[dougkeenan]

Thanks for pointing that effect out. I was indeed using the EDS to get to a higher orbit, nice to know it's not necessary!

The problem may be my mass estimates. I just went googling for values by checking various sources, so any or all could be way wrong. (The thrust numbers are easier to find.)

#define LSAM_TOTAL_MASS (44839)
#define LSAM_MAX_PROP_MASS (28384)

#define CEV_TOTAL_MASS (20500)
#define CEV_MAX_PROP_MASS (3700)

#define EDS_TOTAL_MASS (259563)
#define EDS_MAX_PROP_MASS (234486)

That EDS figure comes from an Ares V doc and is almost twice what I was using before. With that configuration the stack makes it through TLI with margin to spare. I'm not sure I trust it, since I found another thread that said the total TLI mass combining EDS, Altair and Orion is 66,900kg. That's almost the CEV and LSAM just by themselves. Something literally doesn't add up.

[tblaxland]

The numbers look OK on face value. After reading some more on the DIRECT ascent, the EDS is used to complete the EPO injection. How much dV to you have left in the EDS after injection to a 200x200km EPO? (EDIT: Or for that matter, how much after a 500x500km orbit?)

---------- Post added at 15:28 ---------- Previous post was at 14:49 ----------

OK, I downloaded your beta and had a look. In the 500 km EPO scenario you provide, you only have 3.007 km/s dV in the EDS, definitely not enough for TLI. The good news is that if you flew to that 500 km EPO using the EDS, then you should have about 3.42 km/s if you launch direct into a 200 km EPO instead. EDIT: Your numbers are not too far of those contained in the documents I linked to here: http://www.orbiter-forum.com/showthr...2064#post92064

Some other comments on the beta (I have only played with it briefly):
1. You call this DIRECT 2.0, but my understanding is that DIRECT 1.0 used the J-130/J-246 and DIRECT 2.0 used 2 x J-232 instead. I'm just trying to understand the terminology. Either way, it is nice work.
2. I recommend putting the scenario files in a Jupiter Direct folder for the release (I've done it myself anyway).

[simcosmos]

Quick comments:

I haven't experimented the recent BETA files in Orbiter but, looking at recent posts, not 100% sure about what mission profile is being simulated.

In any case and as mentioned on my first post, DIRECT v1.0 is outdated (including what I have uploaded back then, at Orbit Hangar Mods: for exploration duties and later launcher variants, it assumed a core powered by two upgraded (with non–consensual ISP specs) RS-68 derived regenerative engines (and related dev. program) and an higher than STS propellant load. Mission Requirements + other constraints have also meanwhile evolved since then, also with related impact on official Constellation work.




The +/- recent design iterations about SSME powered J130 (for enhanced LEO duties or even conceptual enhanced +/- near term capabilities beyond LEO, if with a Delta IV Heavy Upper Stage, or something similar) and later J246 / J247 variants (in such cases, with RL-10 derived upper stage, with the 'B2' or 'A4' variants being part of the options tree, together with J-2X) aren't really DIRECT *v2.0* (on v2.0+ cores are powered by RS-68 closer to current specs for early J120 and by eventual RS-68 upgrades - whatever such upgrade would end up by being required to be - for the heavier lift duties core, with an extra engine) but, instead, are part of something *beyond v2.0* and which is being currently worked by DIRECT Team (from which I'm one of the members of the public team portion) at the light of updated assumptions of several nature.




Of course that, as happened in past occasions, such work will see the light of the day in a more coordinated way (also including, among other things, my part in the Orbiter simulator front) but, for the moment, some fragments of the overall ongoing work are then being publicly shared / discussed at the also referenced nasaspaceflight forums in the thread about v2.0 although, and yet again (sorry for the repetition), those recent SSME powered launcher configurations really need to be put in the context of something slightly beyond *v2.0* (in terms of launcher configuration details, not in terms of overall philosophy).


Regardless that, if trying to simulate LEO-LOR mission profile then one of the launchers would contain only the EDS (with only a small cover on the top and some latches to later interface with LSAM’s adapted cradle)… The other launcher, also equipped with an upper stage, would have a 10m diameter SLA covering Altair, its cradle and part of Orion SM (the SLA / PLF for direct comparisons with Constellation would *not* cover the whole upper stage) and, at the top, the CEV CM would be covered by the LAS.

Happy development,
António



PS1: have noticed that one of Ross Tierney’s image is in the doc folder as well one of my older MLP dummy / placeholder .dds in the textures folder. Despite this is BETA / Work-in- Progress, perhaps a link to the DIRECT site would be a nice thing to have, on the docs / readme.


PS2: to tblaxland, I have been busy with other things and do not check regularly Orbiter forums as used to do (neither sure when will check again) but please allow me to use this opportunity to make one or two updated observations related with things written in other threads:

a) DIRECT does not currently relies on propellant transfer to meet intended Constellation goals (although can understand why people might think it does): this to say that any cryogenic propellant transfer related with DIRECT needs to be looked at in the proper context of where it appeared (and still appears / will appear) and in the context of further updated work / assumptions. We will try to properly clarify the topic on eventual future public materials.

b) Would also like to note that when comparing AresV expected performance payload with Jupiters also expected performances some care should be taken about things such as injection goals, mission design (and other details) and about what the payload number really means (I apologize in advance if being incorrect but I think that you once said that the AresV had a payload of 188t!, which is not correct!!! The expected AresV *gross payload* for the 51.00.48 vehicle (5.5 seg. SRB + 10m core tank bigger than Saturn V first and second stages + 6 x RS-68B ablative nozzles, J-2X powered US) is ~150t to 222km / ~28.5inc LEO and about 10t more or so for the 51.00.47 iteration (with other more 'agressive' SRB assumptions)… Being that both these iterations might already be outdated due to some other ongoing things related with the technical, economical, etc constraints required to implement such kind of launch vehicle which, each time more and if things do continue this way, is becoming less and less one SDLV design and is becoming closer to a whole new clean sheet design, loosing some of the advantages that an SDLV based heavy lift VSE implementation could still have, even if SDLV is not a perfect path either, at least if considering a trade space, in an ideal world, free of some constraints)

[dougkeenan]

Originally Posted by tblaxland

 The numbers look OK on face value. After reading some more on the DIRECT ascent, the EDS is used to complete the EPO injection. How much dV to you have left in the EDS after injection to a 200x200km EPO? (EDIT: Or for that matter, how much after a 500x500km orbit?)
---------- Post added at 15:28 ---------- Previous post was at 14:49 ----------

OK, I downloaded your beta and had a look. In the 500 km EPO scenario you provide, you only have 3.007 km/s dV in the EDS, definitely not enough for TLI.

Yeah, it was almost enough (took 10% of LSAM descent stage to complete). Bad news is that was a skewed demo - I refilled the tank after getting to the higher orbit, figuring if a full tank couldn't push me then a fractionally filled tank had no chance.

The good news is that if you flew to that 500 km EPO using the EDS, then you should have about 3.42 km/s if you launch direct into a 200 km EPO instead. EDIT: Your numbers are not too far of those contained in the documents I linked to here: http://www.orbiter-forum.com/showthr...2064#post92064

Some other comments on the beta (I have only played with it briefly):
1. You call this DIRECT 2.0, but my understanding is that DIRECT 1.0 used the J-130/J-246 and DIRECT 2.0 used 2 x J-232 instead. I'm just trying to understand the terminology. Either way, it is nice work.

As I understand it, Direct 2.0 is (1) CEV+LSAM on one Jupiter-130 (one stage, three SSME) and (2) EDS on an J246 (two stages, four SSME on the first, 6xRL10 on the second). I tried to get an answer about how much the EDS burns for EPO but with no success.

The above could very well be wrong. Sorting out the details and terminology is part of the exercise!

2. I recommend putting the scenario files in a Jupiter Direct folder for the release (I've done it myself anyway).

Sure, this is all real raw.

---------- Post added at 09:43 AM ---------- Previous post was at 09:38 AM ----------

Originally Posted by simcosmos

 Quick comments:

I haven't experimented the recent BETA files in Orbiter but, looking at recent posts, not 100% sure about what mission profile is being simulated.

CEV->ISS alone or with payload, CEV+LSAM docking, that stack docking with EDS, and EDS pushing to LLO. Almost.

PS1: have noticed that one of Ross Tierney’s image is in the doc folder as well one of my older MLP dummy / placeholder .dds in the textures folder. Despite this is BETA / Work-in- Progress, perhaps a link to the DIRECT site would be a nice thing to have, on the docs / readme.

That is an excellent suggestion, a sorry oversight on my part, and I'll correct it next version. Thanks!

-=-=-

ETA: Some of the above is very well be wrong. Crewed lunar involves two J246, one reusing its upper stage for EDS and the other lifting the CEV-LSAM. I've been using the wrong rocket! No wonder it struggles to get to orbit or beyond. This J246 beta leaves out an entire stage (!) I need to now install. Need new fairings too.

[tblaxland]

Originally Posted by simcosmos

 a) DIRECT does not currently relies on propellant transfer to meet intended Constellation goals (although can understand why people might think it does): this to say that any cryogenic propellant transfer related with DIRECT needs to be looked at in the proper context of where it appeared (and still appears / will appear) and in the context of further updated work / assumptions. We will try to properly clarify the topic on eventual future public materials.

I'm a bit confused by your statement but that sounds to me like you are trying to design it out, or you already have but not released it publicly (except perhaps on nsf?)? Anyway, I'll keep my mind and eyes open for your updates

Originally Posted by simcosmos

 b) Would also like to note that when comparing AresV expected performance payload with Jupiters also expected performances some care should be taken about things such as injection goals, mission design (and other details) and about what the payload number really means (I apologize in advance if being incorrect but I think that you once said that the AresV had a payload of 188t!, which is not correct!!! The expected AresV *gross payload* for the 51.00.48 vehicle (5.5 seg. SRB + 10m core tank bigger than Saturn V first and second stages + 6 x RS-68B ablative nozzles, J-2X powered US) is ~150t to 222km / ~28.5inc LEO and about 10t more or so for the 51.00.47 iteration (with other more 'agressive' SRB assumptions)… Being that both these iterations might already be outdated due to some other ongoing things related with the technical, economical, etc constraints required to implement such kind of launch vehicle which, each time more and if things do continue this way, is becoming less and less one SDLV design and is becoming closer to a whole new clean sheet design, loosing some of the advantages that an SDLV based heavy lift VSE implementation could still have, even if SDLV is not a perfect path either, at least if considering a trade space, in an ideal world, free of some constraints)

Hmmm, it looks like I was using some out of date information. Thanks for the clarification.

[simcosmos]

Small post only to link to NSF and to kind of clarify a little better what have mentioned in my previous posts:

a) The SSME powered core Jupiter Configurations (and related Upper Stage options) are part for something that is *beyond* DIRECT v2.0... (using updated trade space due to also updated information of several type)

b) The link should also clarify a little about what are the intended mission modes as well should provide a better updated context about the eventual role of a propellant depot vs exploration architecture options

In any case, please note that what is shared at nasaspaceflight is a minor part of the overall work in progress and that due to the constraints and nature of such sharing procedure, it might not be fully ready, contain bugs, etc, etc. With this disclaimer, the link for some imagery made by Ross about the mission modes is:

http://forum.nasaspaceflight.com/ind...7497#msg397497

(Lunar Mission Profiles for DIRECT, showing both early Phase 1 and eventual later 2020+ Propellant-Depot enabled Phase 2)

António

PS: still about the more than 180t LEO delivery number sometimes associated with AresV: as mentioned above, some care should be taken when comparing different launch vehicle capabilities in what regards what are the exact configurations / design iterations being compared, their injection targets and about what exactly the delivery mass is all about... In the ~>180t AresV case, such number includes also the mass of the upper stage + boil-off reduction kit, beyond payload adapter / support hardware, the 'true' payload itself (in this case the LSAM), upper stage propellants (for beyond LEO mission = the TLI propellants), margins...)... All that is what makes that ~>180t value to a given LEO delivery target, unless I'm making a wrong interpretation and, in such case, please someone feel free to properly justify that ~>180t number with other explanation

[dougkeenan]

Originally Posted by simcosmos

 a) The SSME powered core Jupiter Configurations (and related Upper Stage options) are part for something that is *beyond* DIRECT v2.0... (using updated trade space due to also updated information of several type)

Ross said : "I am pleased to announce that by almost unanimous vote of both our engineering team and our public team together, we have decided to break with the Constellation Program's baseline choices and DIRECT is officially moving to a position of baselining the Space Shuttle Main Engine as our primary Main Propulsion System for the Jupiter launchers." Do you mean to say he's talking about a version beyond Directv2.0 here?

eta: Serves me right for reading OF before NSF. Direct 3.0 is now active !