Project NASA Constellation SC

[Star Voyager]

I knew the Apollo CM had the cover, but it looks like Orion has a fairing that covers everything. Maybe I'm not understanding this at all. Would Orion abort "Apollo style":

Or "Soyuz style" with the whole fairing being pulled away?

 

[simcosmos]

Hi all

Star Voyager:

The Soyuz abort system takes ~half of the fairing with it because the orbital module is above the capsule. In Orion's case, just the CM is extracted from the vehicle although the overall integration kind of looks like an unique faring because of the way several components smoothly interface.

What you externally see on the second image (about EFT-1) are then 4 different main components, from bottom to top:
a) Adapter linking the ~5.1m diameter of DIVH upper stage's LH2 tank wall until clearing such tank's upper dome and ending at a diameter of ~5.5m. On top of such adapter is the Orion's spacecraft adapter, where the service module 'sits' (see next)
b) 3 fairings that fully enclose the spacecraft adapter and the smaller diameter of Orion's SM
c) at the top of those fairings, there is also a visible part of the SM – with a larger diameter – exposed to external elements and where the CM is integrated
d) finally there is the LAS

The different components are more evident in NASA's animations, documents, etc. I also think that they are perceptible on my past previews but I'm attaching a new quick screenshot pair (sorry for the lack on anti-aliasing) where the different components may be better understood.

At the top of the image, we are seeing the jettison of the SM fairings, some seconds after first stage separation (the solid stage can still be seen in background, together with spent US ullage motors that help J-2X's ignition). The bottom of the image shows the nominal jettison of the abort system, a few seconds after the SM covers go away.


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Other quick DEV comments:
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CEV-E will perhaps include a LAS design similar to Apollo (conical protective cover) and its SM will be left exposed (the solar panels for that CEV are at the bottom of the SM). For the several Orions, an ogive LAS will be integrated (my own or francisdrake's LAS, in the case of Orion MPCV >> as seen in the new preview).

I will also try to include my Orion, but, as mentioned, if doing such, it will mostly be to avoid external addon requirements as a default state for the addon: my spacecraft will still need some serious updates although it will be minimally usable for ascent and orbital ops. I hope to provide more eye-candy for a next post (not sure when).

What follows now is the boring part of checking things out, final tweaks, new tests and... some early documentation notes (just the basics, to be improved later). Then is final packaging / testing in a clean Orbiter.

Probably aiming for February, depending of how things go... So that I can then focus on launch pads, AresV, Altair.

Thanks,
António Maia

 

[Star Voyager]

Alright, that makes much more sense. Thank you for explaining :speakcool:!

 

[simcosmos]

Hello all


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Orion 607 (SC) - CSM Preview
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Not being able to advance as fast as would like, I will attach a new image about the work in progress.

Context: when 'playing' with the files I found myself looking, each time more, at the Orion 3D model that I was planning to release. I then felt an 'urge' to revamp it a little (like what have done to AresI) in order to also make the spacecraft look better.

Despite the rework, this Orion will still mostly be a visual placeholder for basic ascent / orbital simulation but these 3D updates will then be more useful for some of the later (post-fresh-release) configuration work (than if I included the older versions of the models).

As can be seen, the Service Module is mostly ready although some details still need work, in particular related with the stowed (launch) configuration, for example, those 6m diameter ultraflex solar arrays need to be canted. There is also some work to be done inside the CM's adapter.

Unlike the SM (which is in part an upgrade leveraged in an older iteration), the command module is practically a 100% fresh start: at the moment, the capsule is just an empty shell - not even textured - but with things being studied (in the 3D editor) for eventual future functionality upgrades. But that may take a while: I may first focus on AresV / Altair.



Orion607 (SC): Performance Notes

I'm probably going for a ~24.5t CSM with a dV of ~1564m/s (with ~2% prop. margin). This means that I will bring back methane-lox as the baseline for Orion's propulsion.

This re-baselining of methane will be a topic that I plan to further highlight here and/or in the documentation or perhaps write about it again when AresV + Altair are shared. For the moment will write that this addon decision is caused by the wish to simulate an heavy Orion mass and, at the same time, to protect for the referenced dV capability vs '1.5' lunar mission requirements.

However, for orbinauts wishing a slightly more challenging spacecraft (and more in agreement with the actual CxP propellant baseline), there will be a very simplistic 'tweak' that anyone can do: it will only be a matter of going to Config\Spacecraft\ folder and then open the related .INI file, comment the 'Methane' ISP line and uncomment the 'Hypergolics' ISP line that I will also leave there. Such action will instantly reduce this Orion's dV to ~1427m/s (if keeping all other CSM masses equal, in order to keep coherency with the AresI payload; else the launcher's payload definition would also need to be changed, etc, the amount of 'tweaking' will depend of each orbinaut playtime objectives).

A difference of ~137m/s may not look like much but, only to give an example, if memory does not fail me, it takes ~60m/s or so to raise from a negative perigee of ~ -20km up to 185 km (AresI suborbital injection). And then there is still the LEO rendezvous with EDS-Altair, beyond the main requirements for the specific lunar mission design and related with Altair AM rendezvous and TEI setup.

All for now,
António Maia

 

[simcosmos]

NASA CxP SC (Dev Phase1): AresI + Orion + Centaur!
(Lower Bookend Missions)
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I. First Release Contents: Objectives Realignment
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As more or less evident from the latest development posts, the scope of an upcoming first release has changed in order to make the package something a little more complete than what I was initially planning (at a cost of time delays, in part caused by new development tasks).

So, when doing preliminary tests with the scenarios, I was still feeling that something was lacking in the 'fun factor' side of the addon, despite I believe that it is clear that this will be a work-in-progress, an addon with incremental tweaks and new capabilities in each release.

The standard scenario for a LEO mission is launching to Orbiter's default ISS but, when thinking about going beyond, I started to think (always a dangerous thing!) that to simply launch a full spec lunar Orion into a ~29 degrees inclination (without a target there) was not enough... Of course that orbinauts are very proficient at playing with scenarios in order to mix several addons (and, at least for francisdrake's CEV-E integration, I may update the original related scenarios to mix francisdrake's CaLV/LSAM with the updated AresI launching the CEV-E) but, despite all that, I decided that it could be cool if I also included something of my own, a default scenario / challenge that does not require external addons and that allows some extra fun in cislunar space.


Because my AresV / Altair versions will be shared at a later moment I then decided to go to 'simcosmos' archives and practically fully revamp a 2006 model of a Centaur stage that I have used back then, on (non-yet-released) 'VSE SC' addon updates or in SimNASA mission design brainstorms (anyone here from SimNASA's LRO - LCROSS - LCOM simulation times?).

Old 2006 'VSE SC' AresI-Centaur:

NASA_VSE_SC_DEVWIP20060509simcosmos
by simcosmos, on Flickr



I.a) AresI-Centaur : Further Context

Despite launching a Centaur on top of AresI was not part of official baseline CxP plans, there have been a number of brainstorms about such alternative scenarios, in the context of Robotic Exploration missions that could contribute for VSE implementation goals (example, request to CxP from USA's National Research Council). Another example: NASA centers (ARC / JSC / JPL) and other authors (also from Lockheed Martin) also evaluated what became known as 'Lower Bookend Missions' for crewed cislunar / NEO missions (using Orion).

Note: Regarding this topic, I also wrote some stuff at nasaspaceflight forums, where have tried to do a slightly more conservative analysis of such capabilities (in some of the early times documents - sep 2006 to feb 2007 - Orion was still referenced as a ~21t spacecraft with a post-LEO docking dV greater than ~1600m/s (!!!).... For orbinauts with LOTS of patience, the following urls may contain interesting readings and additional links:
http://forum.nasaspaceflight.com/index.php?topic=21467.0
(my posts start on page 4 of that thread but, perhaps more relevant for the current Orbiter Forum post, is http://forum.nasaspaceflight.com/index.php?topic=21467.msg589903#msg589903 )





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II. NASA CxP SC Addon and Lower Bookend Missions
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I have then decided to use the current NASA CxP SC addon development context to update the brainstorm about Lower Bookend Missions with an heavier ~24.5t Orion mass.

The generic concept is about launching a slightly modified Centaur into LEO, where the stage will achieve a stable orbit with an almost full propellant load. It is also a good excuse for sharing fairings for this AresI (and yes, identical capability could be achieved with an heavy version of Delta IV or AtlasV but I'm using what have now more readily flying here).

This scenario should then be good for orbinauts to practice Orion rendezvous / TLI procedures with such Centaur acting as the departure stage. Just like in AresI-V '1.5' mission mode, the launch order for this dual AresI 'Lower Bookend Mission' should probably deserve a proper study / consideration by orbinauts: should we launch the crewed AresI first (vs analysis of several risks) or should we accept a greater boiloff hit (if launching the Centaur first) vs probability of delayed second launch? Things like that, in case someone wishes to follow a stricter set of (non-obligatory) simulation rules and study what results from that!


The final mission capability will depend of several constraints and of updated assumptions... With an heavy Orion, the TLI has the extra fun factor of being a split procedure (with Orion having to undock, rotate 180 degrees and do the remaining part of that burn).

At very least, it should be possible to achieve a free return lunar flyby trajectory (shades of conceptual Gemini-Centaur plans). Going to EML2 (via propulsive lunar swing-by) may also be a possibility but that will require extra tweaks to Orion assumptions and a much, much better mission preparation and implementation (it may be a good way for some orbinauts to spend the time while waiting for AresV / Altair)


Ho, and of course there is always the possibility to use something else other than Orion, with this Centaur EDS. In fact, the optimum crewed spacecraft mass for this kind of dual 'EELV class' launched 'Lower Bookend Mission' would be something a bit closer to an upgraded Soyuz or Shenzhou (less than ~8t mass)... Such spacecraft mass could perhaps even allow full TLI and insertion + departure from some kind of higher lunar orbit... Only for comparison, Orion's capsule alone is already above that mass limit


To end, a quick heads up: I plan to attach here a new preview of the revamped Centaur 3D model. As usual, please do not pay much attention to details: there are obvious simplifications, other things are incorrect, etc but I will be happy if people look at it and, at a first glance, still recognize the stage as some kind of alternative Centaur configuration. This model may be later used to improve these types of brainstorms (such as robotic lunar landers or additional kits to improve the stage's in-space endurance).

All for now,
António Maia

PS: There is still one last thing that I'm not quite happy with and which may review for a first release: launching from Orbiter 2010's default pads (but that will be a topic for a future post).


EDIT: Centaur EDS preview has been attached :hello: