DIRECT v3.0 - Thread 1

[MP99]

But look at the NSC proposal in detail. What Shannon basically proposed are 4-6 flights of a Block I vehicle, which would salvage every spare part and actual flight part of the current Shuttle stack - which includes avionics currently used in the active orbiters. Of course once those (and the 14 SSMEs which are available) are gone, you need to come up with a replacement.

An alternative idea, what if the bottom module, with the engines, were ejectable and reusable.  Say upon the point that the main tank is shedded, the bottom portion could eject and parachute down in some safe manner?

The engines can be replaced for less than the cost of refurbishment, anyway.

Your argument actually boils down to ejecting and attempting recovery of the avionics, not the whole boattail.


Actually, on Orion flights, the simplest way to do that would be to mount them remotely in the Orion (if space can be found).

cheers, Martin


Edit: fixed quoting.

[MP99]

Jupiter has been described as a one-and-a-half stage vehicle

Martin,
Please be very careful using that term.   It actually means something very specific which has nothing at all to do with Jupiter.

I know Ross has previously explained where the other 28kg goes - I think it's related to the proportion of post-ascent fuel which boils off before TLI.

Engine purge after shutdown.

Ross.

Thanks for those.

cheers, Martin

[Downix]

Unfortunately the hardware which the Shuttle systems currently run upon is completely antiquated.    And worse, there are no real equivalents today which are code-compatible any more either so they're almost impossible to build in significant numbers -- so you really have few options but to start afresh.
Ross.

Is there any way for a normal citizen to get ahold of the existing shuttle system controller specs?  You say there's nothing capable of running the existing software, but I'm curious what hardware currently runs it, to see if a bridge could be built.  (you just hit my area of enjoyment, replacing ancient hardware to run specialized software)

Honeywell in Clearwater FL makes and services the SSMEC.  I have a friend who works on it.  I am sure the info is all proprietary, though.

Oh cool, I drive past them most mornings.  But I figured it would be propriority.  Never hurts to ask however.

Actually, there is am interesting 1987 paper describing the newer version of the shuttle computers. It's named "The New AP101S General-Purpose Computer (GPC) for the Space Shuttle". It's not available for free on the Internet, though that could be arranged ;-)...
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1458005

You might also be interested in a more high-level description with lots of fun details here (and, also not available free of charge) here http://portal.acm.org/citation.cfm?id=358234.358246

Ooo, I know that, well, the older AP101 it's based on.  Derived from the IBM S/360 mainframe, using core memory.  I cut my mainframe teeth on the 360!  (don't mind me geeking out a bit, have not been able to enjoy any mainframe time in over a year)

[dougkeenan]

The 2896kg listed as Ascent Flight Performance Reserve is the same as the Pre-TLI Overboard mass, is that right?  Also, CLV values are identical except for the Usable Post-Ascent Propellant value?

[Downix]

But look at the NSC proposal in detail. What Shannon basically proposed are 4-6 flights of a Block I vehicle, which would salvage every spare part and actual flight part of the current Shuttle stack - which includes avionics currently used in the active orbiters. Of course once those (and the 14 SSMEs which are available) are gone, you need to come up with a replacement.

An alternative idea, what if the bottom module, with the engines, were ejectable and reusable.  Say upon the point that the main tank is shedded, the bottom portion could eject and parachute down in some safe manner?

The engines can be replaced for less than the cost of refurbishment, anyway.

Your argument actually boils down to ejecting and attempting recovery of the avionics, not the whole boattail.


Actually, on Orion flights, the simplest way to do that would be to mount them remotely in the Orion (if space can be found).

cheers, Martin
[/quote]
Once you get to that stage, however, you may as well go fully disposable and instead ramp up production volume with a CR process to bring the costs down. 

[dougkeenan]

 69,892kg  Usable Ascent Propellant
    102kg  Ascent In-Flight Losses
  2,896kg  Ascent Flight Performance Reserve
 99,896kg  Usable Post-Ascent Propellant
  1,009kg  Post-Ascent Flight Performance Reserve
  1,723kg  Unusable Residuals
=========
175,491kg  Total
=========

175,519kg  Maximum Gross Propellant

Every time I add those six numbers I get 175518.  Metric system?  Banker math?

[kraisee]

The 2896kg listed as Ascent Flight Performance Reserve is the same as the Pre-TLI Overboard mass, is that right?  Also, CLV values are identical except for the Usable Post-Ascent Propellant value?

Yep.   You don't want to be carrying any additional mass thru TLI which you don't have to.

So a 'nominal' mission should arrive in LEO with that 2.9mT of extra mass.   You will want to dump it before the TLI.

Ross.

[kraisee]

 69,892kg  Usable Ascent Propellant
    102kg  Ascent In-Flight Losses
  2,896kg  Ascent Flight Performance Reserve
 99,896kg  Usable Post-Ascent Propellant
  1,009kg  Post-Ascent Flight Performance Reserve
  1,723kg  Unusable Residuals
=========
175,491kg  Total
=========

175,519kg  Maximum Gross Propellant

Every time I add those six numbers I get 175518.  Metric system?  Banker math?

LOL!

Just not showing the decimals.   Here:-

Ascent Propellant:   69,892.21kg
Ascent FPR (1%):   2,895.87kg
TLI Propellant:   99,896.47kg
TLI FPR (1%)   1,009.06kg
In-Flight Losses:   101.87kg
Residuals:   1,723.27kg

Total Propellant:   175,518.76kg

Ross.

[ballew]

Does the Direct team have any plans to have a presence at the Huntsville Public Meeting on the 29th?

[jjnodice]

Does the Direct team have any plans to have a presence at the Huntsville Public Meeting on the 29th?

Sounds like another fund raiser is in order...

[ar-phanad]

Does the Direct team have any plans to have a presence at the Huntsville Public Meeting on the 29th?

Sounds like another fund raiser is in order...

Anyone have an idea what's on the agenda for these?

[MikeAtkinson]

I don't understand where the IMLEO 208.1mT in the DIRECT_ISDC_2009.pdf for the PD comes from. I suspect this has been answered before, but I can't find it.

[kraisee]

Mike, the IMLEO figure represents the total mass of Orion, Altair, its ASE Cradle, the EDS and the TLI propellant inside it -- all together, specifically as they all stand just prior to making the TLI Burn.

Ross.

[kraisee]

Announcement:

"To The Moon"
NPR -- Science Friday with Ira Flatow
(broadcast Friday, July 17th, 2009)

http://www.sciencefriday.com/program/archives/200907171

Guests:

Alan Bean, Apollo 12 Astronaut & Moon-walker
Dr. Harrison Schmitt, Apollo 17 Astronaut & Moon-walker
Andrew Chaikin, Author and Journalist
Ross Tierney, Founder of The DIRECT Team


I would be very grateful if someone could please ensure this gets recorded somehow!


Regards,

Ross Tierney
www.directlauncher.com
www.launchcomplexmodels.com
--
"Why is there not more thinking in the direction
of developing the simplest scheme possible?"
                        -- John C. Houbolt, 1961

[dougkeenan]

WOW!  Way to go Ross!!!

[robertross]

WOW!!!!  (grinning from ear to ear)

Awesome Ross. Congrats!

[rv_rocket]

I'd love to have local get-togethers to hoist a pint in celebration of reaching the long-standing goal of getting an independent review of all available options on a level playing field.  Perhaps on the day that the Augustine Commission presents its report?

That's exactly what I'm planning.

As we get closer to the 30th, I'll get everyone to confirm so that we can book a table large enough at a restaurant in the area.

Ross.

Count me in!! I should be able to make it by 7pm. I'll try to get there earlier if I can.

And good luck on the NPR show!!
 

[kraisee]

Is there a radio equivalent of the stage/film good-luck charm "break a leg"?

Ross.

[kraisee]

Does the Direct team have any plans to have a presence at the Huntsville Public Meeting on the 29th?

We have more than a few team members in the area, but I'm not sure if any of them are willing to "break cover" publicly.

At the DC hearing there was a chap, Osa Fitch, who used his three minutes to make a case for something very similar to DIRECT.   I had no idea anyone else was going to say something so similar independent of us, but he did.   I managed to have a word afterward and was able to express my thanks to him for his comments.

I'm keeping my fingers crossed that even if we don't get any team members to speak publicly, that we at least get a few more members of the public to make a very reasoned case, just as Mr. Fitch did.

Ross.

[Bill White]

I would be very grateful if someone could please ensure this gets recorded somehow!

FWIW, following the link to NPR it appears their website has MP3 links for prior shows.

Please - everyone - do not be dissuaded from recording this just in case I'm wrong, but it appears that NPR records its shows and makes the audio available after the fact.