Author Topic: DIRECT v2.0 - Thread 2  (Read 1356649 times)

Offline A_M_Swallow

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Re: DIRECT v2.0 - Thread 2
« Reply #720 on: 06/18/2008 02:22 am »
NASA:

1.  Large NASA payloads purchased as commercial launch services.   NASA could still go to the moon on a Jupiter - even if they aren't building the rockets themselves any more.
{snip}

1. If there is a commercial Jupiter, there is no NASA lunar program.  They are mutually exclusive.


Public Relations definition of NASA lunar mission.

NASA LSAM
NASA astronauts
NASA lunar outpost
NASA sign on pad
NASA press release
NASA money.

That sounds like a NASA lunar mission.

Offline Jim

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Re: DIRECT v2.0 - Thread 2
« Reply #721 on: 06/18/2008 03:55 am »
NASA:

1.  Large NASA payloads purchased as commercial launch services.   NASA could still go to the moon on a Jupiter - even if they aren't building the rockets themselves any more.
{snip}

1. If there is a commercial Jupiter, there is no NASA lunar program.  They are mutually exclusive.


Public Relations definition of NASA lunar mission.

NASA LSAM
NASA astronauts
NASA lunar outpost
NASA sign on pad
NASA press release
NASA money.

That sounds like a NASA lunar mission.


wrong again as usual.  The point is if NASA isn't funding Ares I & V or Direct, then NASA isn't funding lunar missions.

Offline Patchouli

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Re: DIRECT v2.0 - Thread 2
« Reply #722 on: 06/18/2008 04:29 am »
A commercial Jupiter could be very useful to the satellite business since com sats mostly geostationary sats are getting bigger and heavier.
Don't believe me just compare the average sat from 15 years ago to one today and then one from 30 years ago you'll see a trend and they're getting huge.
24ton class vehicles may not be up to the job in the future since there are demands for higher data rates and smaller devices on the receiving end this means the com sat need to be more powerful in transmission power.

Though if we stick with Ares there is no moon program it'll continue to cost more and will get cut when congress realizes the damage it's doing to the other part of NASA.
Ares I with out Ares V doesn't equal a moon program and instead equals another X33 fiasco.

BTW I don't see why NASA can't just buy EELVs,Falcons, Taurus IIs etc other then pride.

I'm sure we can safely say the myth of Ares I being safer then an EELV has been throughly killed with all the evidence of instability and deadly oscillation issues etc.

On what someone said about docking port stress on a two engine EDS if the structural margins of LIDS are so narrow that a two engine EDS even with throttling would break it then we should not be using it.
That makes me wonder if it would have the usual pressure safety margin of being able to take 1.5 to 3x norm before failure NASA usually has on stuff.
The old Apollo LEM windows were pressure tested to over 25psig to verify the safety.

Might be best to beef it up so it can handle the stress this also will allow the standard to be used in the future on larger and heavier vehicles and space tugs.
« Last Edit: 06/18/2008 04:50 am by Patchouli »

Offline Jim

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Re: DIRECT v2.0 - Thread 2
« Reply #723 on: 06/18/2008 04:37 am »
A commercial Jupiter could be very useful to the satellite business since com sats are getting bigger and heavier.
Don't believe me just compare the average sat from 15 years ago to one today and then one from 30 years ago you'll see a trend and they're getting huge.


wrong. Jupiter is too big.  Comsats have yet to max out current vehicles

Offline Patchouli

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Re: DIRECT v2.0 - Thread 2
« Reply #724 on: 06/18/2008 04:58 am »
wrong. Jupiter is too big.  Comsats have yet to max out current vehicles
[/quote]

Not yet but they are going to might take another 15 to 20 years but it's not a matter of if just when.

Still even now they could use it if it's very reliable to launch two or three big birds at once.
This would save on logistics and lower the over all cost but would increase risk since a failure will destroy 3 satellites vs one.

The DOD also could use it to replace large military payloads in bulk or test their solar power sat concepts.

Now space probes have already maxed out existing vehicles a few times and the same with space telescopes they just can't get enough payload it seems.

Then you have the emerging space tourism and space research market which could quickly find use for a vehicle the size of the J-120.

Though that last market might be better served by small RLVs or the experts on that market seem to think so.

But if you're building a space station like bigelow is there is no such thing as too big of a vehicle except maybe something crazy huge like Ares V but then it's not it being too big thats the issue it's that it's just too expensive for anyone to afford.
« Last Edit: 06/18/2008 05:10 am by Patchouli »

Offline simonbp

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Re: DIRECT v2.0 - Thread 2
« Reply #725 on: 06/18/2008 05:15 am »
If anything Com sats will get smaller; as Jim said, there is no commercial market for Direct...

If Direct is ever accepted, it will be as a new iteration of Ares (probably as "Ares II" and "Ares IV" or somesuch). The purpose of Ares, in both current and any future Direct iteration, is to launch Constellation missions, and not much else. Besides, I can't realistically imagine a flight rate much higher than STS, meaning all that capacity is need for lunar flights...

Simon ;)
« Last Edit: 06/18/2008 05:18 am by simonbp »

Offline gladiator1332

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Re: DIRECT v2.0 - Thread 2
« Reply #726 on: 06/18/2008 05:29 am »
The only other possibility will be for Mars Sample Return or other larger JIMO sized probes.

Offline Patchouli

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Re: DIRECT v2.0 - Thread 2
« Reply #727 on: 06/18/2008 05:48 am »
If anything Com sats will get smaller; as Jim said, there is no commercial market for Direct...

If Direct is ever accepted, it will be as a new iteration of Ares (probably as "Ares II" and "Ares IV" or somesuch). The purpose of Ares, in both current and any future Direct iteration, is launch Constellation missions, and not much else. Besides, I can't realistically imagine a flight rate much higher than STS, meaning all that capacity is need for lunar flights...

Simon ;)

I don't see them getting smaller and we're getting very close to the theoretical limits of solar cell efficiency.

Coms sats are not personal computer though they do have computers.
Instead they are radio relay stations in space so your not going to see
an 18KW sat shrunk down to something you can carry in your pocket for many of the same reasons you will not see a power plant become tiny.

But yes there are things they can do and are doing to make them lighter such as using Lipo batteries in place of nickel hydrogen cells , using ion thrusters in place of arcjet thrusters and use of composites in the structure plus lastly the recent developments in solar cells.

 Some stuff is just physics if you want to push a lot of data over a far distance over a wide area you need power.

Not everyone wants an 8 foot dish on their house to receive 100 HDTV channels from one sat.

Increases in satellite transponder power are one of the the main reasons as to why you can receive digital tv with an 18" dish now vs needing a eight foot dish as was the case 20 years ago.
The switch to KU band made the LNB and dish smaller too.

Very high power transponders are what made things like XM radio even possible.
Sat transponder output has grown from 4 watts for early C-band to 50 to 80 watts per channel.
Your typical Boeing 702 or Astrium E3000 have 18KW and 14KW solar arrays.

Though LEO and mid orbit sats can be much smaller as with Iridium only 700Kg each but these also need to be numerous for continuous coverage for obvious reasons.

But GEO sats are forced to be large machines unless you want the ground equipment to be large to gather a weak signal .
« Last Edit: 06/18/2008 06:02 am by Patchouli »

Offline A_M_Swallow

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Re: DIRECT v2.0 - Thread 2
« Reply #728 on: 06/18/2008 07:28 am »

wrong again as usual.  The point is if NASA isn't funding Ares I & V or Direct, then NASA isn't funding lunar missions.

Irrelevant.

Offline renclod

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Re: DIRECT v2.0 - Thread 2
« Reply #729 on: 06/18/2008 08:41 am »
Dual J-2X (or dual J-2??? for that matter) EDS is problematic.

Quoting from 20080018610_2008018440.pdf @ ntrs :
Quote
For the EDS reignition, the J–2X will shift
to a secondary mode mixture ratio of 4.5 and attain roughly
241,000 lbf (1072 kN—82 percent) thrust to accommodate
load limits on the Orion/Altair lunar lander docking system
.

With the proposed dual engine EDS, and if the load limit issue stands, "Direct" would be forced to explore a bizzare single engine TLI / dual engine launch...


... or the unthinkable beefing of up the docking system.



Beefing up the docking system ... hmm... I wonder why those square heads @ NASA didn't thought about such a simple solution. Why messing up with the J-2X power level when you can have even two engines and for example:

1/ replace the LIDS with CBM !

or
2/ keep the LIDS but stage an pre-TLI EVA to attach I beams between Orion and Altair !

or
3/ keep the LIDS but don't use it until after TLI (a la Apollo); this one was proposed by "Direct" some time ago, and mandates cutting openings in the shroud to let the solar arrays deploy.

The problem is not simple and I would say aggravates with increasing Orion's mass (in fact moment of inertia).

Another thing: what you make you must also break - this is a critical requirement, if un-docking Orion from Altair fails, it's a very bad situation, especially for return and entry. So any "beefing up" must take this into account too.

NASA solution so far: single J-2X EDS, reduced power level for TLI, disposable LIDS.

IMO.


Offline Ronsmytheiii

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Re: DIRECT v2.0 - Thread 2
« Reply #730 on: 06/18/2008 11:21 am »

1/ replace the LIDS with CBM !


CBM is a berthing mechanism, not a docking port.  Also in Direct docking would only take place after TLI, so no worries for the docking system.

Offline guru

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Re: DIRECT v2.0 - Thread 2
« Reply #731 on: 06/18/2008 12:15 pm »

Beefing up the docking system ... hmm... I wonder why those square heads @ NASA didn't thought about such a simple solution.


Yeah, I mean, why wouldn't those "square heads" want to add mass to a capsule from which they already had to strip multiple redundant safety systems (which weighed more than a beefed up docking system would) and mission capabilities because the Ares I rocket on which they intended to launch it couldn't even lift the original design?  I just don't get it either.

Offline kraisee

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Re: DIRECT v2.0 - Thread 2
« Reply #732 on: 06/18/2008 12:42 pm »
Guys,
This whole issue of a commercial Jupiter is a moot point.   If NASA doesn't build it first, no commercial entity will.   Arguing about how it might or might not work is a completely pointless exercise given that overriding fact.

The *only* way a commercial Jupiter might ever fly would be in *addition* to a healthy and robust NASA operation running in parallel.   In that scenario all the arguments change anyway.   And I still believe there's less than a 5% chance of a commercial venture doing that even in such a positive environment.

So I'm going to ask that this topic be spun off from this point on into a separate thread - here.   It has nothing to do with what we're trying to achieve here and I don't think a single person on the DIRECT Team really expects to see a commercial Jupiter launch.

If people want to argue about minutiae in such a hypothetical situation, please do so in the other thread.   Not this one.   Thanks.

Ross.
« Last Edit: 06/18/2008 12:49 pm by kraisee »
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline renclod

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Re: DIRECT v2.0 - Thread 2
« Reply #733 on: 06/18/2008 12:48 pm »

1/ replace the LIDS with CBM !


CBM is a berthing mechanism, not a docking port. 
Thanks for the clarification. It confirms what I already suspected after reading this:
http://spacecraft.ssl.umd.edu/design_lib/ICES01-2435.ISS_CBM.pdf

Quote
Also in Direct docking would only take place after TLI, so no worries for the docking system.

Let's ask Ross or Chuck about this. I'd say your "Direct" is off the baseline. My knowledge about "Direct" supports my post, i.e. Orion docking with Altair before rendezvous with the second J-232 (the one with fully fueled, dual engine EDS), so before TLI.


Offline clongton

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Re: DIRECT v2.0 - Thread 2
« Reply #734 on: 06/18/2008 12:51 pm »

Beefing up the docking system ... hmm... I wonder why those square heads @ NASA didn't thought about such a simple solution.

Yeah, I mean, why wouldn't those "square heads" want to add mass to a capsule from which they already had to strip multiple redundant safety systems (which weighed more than a beefed up docking system would) and mission capabilities because the Ares I rocket on which they intended to launch it couldn't even lift the original design?  I just don't get it either.

The answer of course is to go thru TLI on the J-2X “eyeballs in”, just like Apollo.
LIDS should not have to be designed as a structural member – that’s dumb.
Detach, rotate and re-dock after TLI, just like Apollo. The Ares architecture can’t do that, but the Jupiter-232 profile can do it. So the answer is, of course, don’t use the Ares. Fly the Jupiter instead. Problem solved.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Jim

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Re: DIRECT v2.0 - Thread 2
« Reply #735 on: 06/18/2008 01:32 pm »

1/ replace the LIDS with CBM !


Not doable.   CBM is not a docking system.  It is a berthing system.  Also it is "weaker" than a docking system

Offline Spacenick

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Re: DIRECT v2.0 - Thread 2
« Reply #736 on: 06/18/2008 01:38 pm »
What about APAS-89? Then docking with Shenzhou and modified Soyuz/ATV would be quite easy or is LIDS as easy to implement for other nations as is APAS?

Offline kttopdad

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Re: DIRECT v2.0 - Thread 2
« Reply #737 on: 06/18/2008 01:54 pm »
NASA:

1.  Large NASA payloads purchased as commercial launch services.   NASA could still go to the moon on a Jupiter - even if they aren't building the rockets themselves any more.
{snip}

1. If there is a commercial Jupiter, there is no NASA lunar program.  They are mutually exclusive.


Public Relations definition of NASA lunar mission.

NASA LSAM
NASA astronauts
NASA lunar outpost
NASA sign on pad
NASA press release
NASA money.

That sounds like a NASA lunar mission.


wrong again as usual.  The point is if NASA isn't funding Ares I & V or Direct, then NASA isn't funding lunar missions.

I disagree with that completely.  NASA has never built a thing on its own - it has always contracted out the construction of its launch vehicles.  The only difference between a lunar mission using the Saturn V and a lunar mission using a commercial launch vehicle is the contract that defines the relationship between the LV builder and the end user (NASA).  The piece of paper defining the ownership of the LV would be the only difference between a "traditional" lunar mission and one utilizing a COTS launch vehicle, and the public would never know (or care) about the difference.  NASA astronauts walking around a NASA moon base is all they would see, and if that could be done more efficiently through the use of COST LVs, then that would be all the better.

I, as a tax payer, would love to see NASA get out of the LV business altogether.  I absolutely feel COTS is the way to go, and that NASA should be a purchaser of vehicle services rather than a builder of vehicles.  If NASA were to commit to X lunar missions per year for the next 30 years using a COTS LV provider, I imagine a way could be found to make a profit.  And every flight would be a NASA flight.
"Do what you can, with what you have, where you are."  -T. Roosevelt

Offline clongton

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Re: DIRECT v2.0 - Thread 2
« Reply #738 on: 06/18/2008 02:11 pm »
NASA:

1.  Large NASA payloads purchased as commercial launch services.   NASA could still go to the moon on a Jupiter - even if they aren't building the rockets themselves any more.
{snip}

1. If there is a commercial Jupiter, there is no NASA lunar program.  They are mutually exclusive.


Public Relations definition of NASA lunar mission.

NASA LSAM
NASA astronauts
NASA lunar outpost
NASA sign on pad
NASA press release
NASA money.

That sounds like a NASA lunar mission.


wrong again as usual.  The point is if NASA isn't funding Ares I & V or Direct, then NASA isn't funding lunar missions.

I disagree with that completely.  NASA has never built a thing on its own - it has always contracted out the construction of its launch vehicles.  The only difference between a lunar mission using the Saturn V and a lunar mission using a commercial launch vehicle is the contract that defines the relationship between the LV builder and the end user (NASA).  The piece of paper defining the ownership of the LV would be the only difference between a "traditional" lunar mission and one utilizing a COTS launch vehicle, and the public would never know (or care) about the difference.  NASA astronauts walking around a NASA moon base is all they would see, and if that could be done more efficiently through the use of COST LVs, then that would be all the better.

I, as a tax payer, would love to see NASA get out of the LV business altogether.  I absolutely feel COTS is the way to go, and that NASA should be a purchaser of vehicle services rather than a builder of vehicles.  If NASA were to commit to X lunar missions per year for the next 30 years using a COTS LV provider, I imagine a way could be found to make a profit.  And every flight would be a NASA flight.

Ross has created a separate thread for ANY AND ALL discussion of a commercial variant of the Jupiter launch vehicles; all applications, whether used by NASA or not.

Please move ALL such posts to the thread that was created for them. They do not belong here. Go HERE instead..
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Jim

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Re: DIRECT v2.0 - Thread 2
« Reply #739 on: 06/18/2008 02:24 pm »
What about APAS-89? Then docking with Shenzhou and modified Soyuz/ATV would be quite easy or is LIDS as easy to implement for other nations as is APAS?

Huh?    APAS is not easy for other nations to implement, they would have to buy the hardware from RSC-E.

Also the issue is about structural capability and not commonality.

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