"DIRECT" Goes Live

[kraisee]

I too wouldn't hold my breath.   But I am hearing that "strange things are afoot at the meatball", so I, for one, am going to be watching NASA very closely around the end of the month - just in case.

If things are afoot, and something like DIRECT were being looked at again, the most critical thing I'd like NASA to consider is to make a derivative which can get us to the moon with only one vehicle - simply used in two different configurations.

Secondly, the approach to designing the rocket is also a critically different one too.   The key is analysing what you have right now flying on STS, carefully deciding what of that hardware can be kept completely unchanged (SRB's), what requires only limited changes (RS-68 man-rating, ET tanking walls milled thicker on CNC machine) and then limiting the bulk of R&D to just those areas which are completely different (Thrust Structure, PL Interface, Avionics).

This latest DIRECT proposal shows how unchanged Shuttle SRB's and a single common core stage design could be used to lift either 50mT payloads or 100mT payloads.   This vast range of performance difference is done simply by adding one engine to the common core and using an upper stage - which you'd need anyway for the EDS.   As long as the common core is designed *from the start* to support this "growth", it can do everything Ares-I and Ares-V can.

DIRECT is really about changing the "way of thinking".   I'm trying to get NASA to just look at the approach from a slightly different tangent, not trying specifically to 'sell' one particular rocket design over another.   Once the change happens in the mind, I think the result will automatically lead to something similar to DIRECT.

Ross.

[Lee Jay]

Where does the tank end up on the heavy version of DIRECT?  I assume, given that there's a good sized upper stage, that it doesn't get nearly as far downrange as with STS or DIRECT standard.

[kraisee]

I have finally finished a comprehensive round of optimizations for DIRECT's "Jupiter" launch vehicle performance numbers.   I have assessed both small and large variants, and also Crew and Cargo configurations of both.   These are using my ESA tools, which historically has proven to be slightly (~2%) below performance of the same vehicle when compared to runs through POST.   Enjoy.

Ross.

---

Jupiter 240 (2x 4-seg RSRM, 2x RS-68 [409.0s]) Crew Launch Vehicle (CLV) config:
* 46,159kg to 46x120nm @ 28.5deg for Lunar missions.
* 41,040kg to 30x220nm @ 51.6deg for ISS missions.

Jupiter 240 (2x 4-seg RSRM, 2x RS-68 [409.0s]) Cargo Launch Vehicle (CaLV) config:
* 48,918kg to 46x120nm @ 28.5deg for Lunar missions. <<< CORRECTED!!!
* 43,741kg to 30x220nm @ 51.6deg for ISS missions.

Jupiter 342 (2x 4-seg RSRM, 3x RS-68 [409.0s], 2xJ-2XD [448.0s]) Crew Launch Vehicle (CLV) config:
* 106,534kg to 80x120nm @ 28.5deg for Lunar missions plus 23,062kg of EDS burnout mass.
* 100,241kg to 80x220nm @ 51.6deg for ISS missions plus 23,062kg of EDS burnout mass.

Jupiter 342 (2x 4-seg RSRM, 3x RS-68 [409.0s], 2xJ-2XD [448.0s]) Cargo Launch Vehicle (CaLV) config:
* 108,301kg to 30x120nm @ 28.5deg for Lunar missions plus 23,062kg of EDS burnout mass.
* 107,721kg to 80x220nm @ 51.6deg for ISS missions plus 23,062kg of EDS burnout mass.


NOTES:

All ESAS margins and GRA's achieved.

Crew Launch Vehicle Solutions Assume:
 * Launch Abort System (LAS) massing 5,600kg, is disposed of at T+200s (this is conservative and can be refined further to improve performance).
 * Payload Fairing (PLF) massing 3,000kg, mounted under the Orion is carried to orbit.

Cargo Launch Vehicle Solution Assume:
 * Payload Fairing (PLF) massing 2,722kg, is disposed of at T+305s (this is conservative and can be refined further to improve performance).

[kraisee]

Lee Jay - 6/5/2007  12:41 PM

Where does the tank end up on the heavy version of DIRECT?  I assume, given that there's a good sized upper stage, that it doesn't get nearly as far downrange as with STS or DIRECT standard.

The exact landing site depends on the specific trajectory, and that analysis has not yet been completed.

For the "Heavy" expect all Core stages to impact somewhere in the Atlantic.   The smaller vehicle's Core stages go all the way to the insertion orbit and do a 'once around' - so where they will return is still a matter of calculating.   Early indications put them in the viscinity of the Pacific Ocean though, so trajectories can be tailored for specific flights to ensure tanks land in designated safe areas.

Ross.

[CFE]

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

Also, do the performance figures for the Crew Launch variants represent payload in addition to the Orion mass, or is it the total mass (including Orion) to the reference orbit?

[Jim]

CFE - 6/5/2007  8:41 PM

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

The whole reason for SRB's are the existing casings and recovery of the boosters.   filament-wound casings negate the ESAS reasoning for using the current SRB's, which BTW have been the only boosters to kill a crew.

[kraisee]

CFE - 6/5/2007  8:41 PM

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

The SRB's on the Jupiter-240 flights (with no U/S) are going to fly in a very similar profile to that on STS, so I would expect (although don't have exact calculations yet) the SRB's to land pretty close to the existing landing area.

On the larger Jupiter-342 flights, the profile is different.   Separation occurs 1010m/s faster (1401m/s vs. 1290m/s), but at a lower altitude (47km vs. 66km).

I don't yet know what this will actually do, but I do know that the ocean-going SRB recovery ships could quite easily operate at double the distance from short that they do currently.   They are expected to be able to support the 5-segment boosters already, and those will fly further than the 4-segs on any LV - so I don't believe this is a concern.

Also, do the performance figures for the Crew Launch variants represent payload in addition to the Orion mass, or is it the total mass (including Orion) to the reference orbit?

Total NET payload mass including the CEV.

Ross.

[MATTBLAK]

I've gotta ask, Ross:

If/when the Direct exchanged solid boosters for Lox/Kerosene ones, depending on the design (2 or 3 RD-180/RS-84/Clean Sheet) how much more payload to a 28.5 degree orbit could a Direct CALV launch? 5-to-10 more metric tons? And if the RS-68 was optimised, 418 or better seconds Isp? 3-to-5 percent more payload? :cool:

[kraisee]

Matt,
   Boy, that's a question with a lot of different answers

   If liquid boosters ever came to fruition, the performance would depend on many different factors, such as:

Which engines would they use? RS-68, Cobra, RD-180, RD-171 and F-1X would all be contenders for such a job, and each has different pros and cons.
How much power would the boosters deliver?
How efficient are the engines?
How long would they burn for?
How heavy are they at liftoff?
How heavy are they at burnout?
How do they affect safety?
What changes would be needed during processing?
What changes are needed to manufacture?

Only once you've got those questions answered, only then can you actually start plugging in numbers and coming back with example solutions.

For my own money, I wouldn't use the RS-68 because you'd require an awful lot of them to match the liftoff power of an SRB, so I would opt for making the 1m lb thrust LOX/LH2 Cobra and use it on both the Core and the boosters.   I would then fly the boosters as disposable units for a while, but begin a development program to be able to recover the boosters/engines for re-use.


As for a more optimized RS-68 - I have already plugged in the numbers for the USAF's RS-68A regenerative engine (418s vac Isp) being built for the Delta-IV completely independently of NASA - and it would improve performance of the Heavy Jupiter-342 by about 7mT to LEO - but that engine costs a lot more than the regular ablative unit, so isn't as cost effective.   Also it has not been tested or flown at this time, so can't be 100% relied upon.

Ross.

[Jim]

RS-68A is not regen.    The mods to make the RS-68A  plus the mods to reduce He consumption and H2 at ignition make up the RS-68B.   There isn't going to be a RS-68 regen

[clongton]

Jim - 7/5/2007  12:15 PM

RS-68A is not regen.    The mods to make the RS-68A  plus the mods to reduce He consumption and H2 at ignition make up the RS-68B.   There isn't going to be a RS-68 regen

Direct v2 does NOT use a regen engine. It is the same engine bring flown today on the Delta-IV, except man-rated.

[kraisee]

Jim, USAF must have the extra performance of the regen for an upcoming Delta-IV flight, so the engine upgrade is already in work.   That engine development upgrade work for Delta-IV has recently been assigned the name "RS-68A" by P&W.   It's minimum performance specification is attached.

I do agree though, that NASA has no plans to use it, or invest in it at the current time. All of those plans all got canned a number of weeks ago.

And we are not using the regen RS-68A for DIRECT - we are using the existing ablative engine, operated at normal Delta-IV power levels.   NASA's numbers indicate the ablative engine can actually be operated at 106% power, but we are leaving that extra power out of our calculations so it can be used as an easy-to-achieve, but not critical, upgrade path later.

Ross.

[kraisee]

I have been consulting with the current DIRECT team again.   Expect some interesting updates within the next 24 hours.

Ross.

[pippin]

Jim - 6/5/2007  3:45 AM

CFE - 6/5/2007  8:41 PM

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

The whole reason for SRB's are the existing casings and recovery of the boosters.   filament-wound casings negate the ESAS reasoning for using the current SRB's, which BTW have been the only boosters to kill a crew.

The Boosters did not kill the Crew. The missing escape system did.

[Jim]

pippin - 10/5/2007  4:50 AM

Jim - 6/5/2007  3:45 AM

CFE - 6/5/2007  8:41 PM

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

The whole reason for SRB's are the existing casings and recovery of the boosters.   filament-wound casings negate the ESAS reasoning for using the current SRB's, which BTW have been the only boosters to kill a crew.

The Boosters did not kill the Crew. The missing escape system did.

Too quick for any abort system to react

[Chris Bergin]

Moved from another thread, but ATK seem to have been really cheeky and set up a page of their own, using what Dr Stanley said on his Q&A about Direct on here on one of their own pages! Very one sided too.

http://www.safesimplesoon.com/mythbusters2.htm

Crikey. This is an actual official ATK site, right?

[Wolverine]

Chris Bergin - 10/5/2007  8:03 AM

Moved from another thread, but ATK seem to have been really cheeky and set up a page of their own, using what Dr Stanley said on his Q&A about Direct on here on one of their own pages! Very one sided too.

http://www.safesimplesoon.com/mythbusters2.htm

Crikey. This is an actual official ATK site, right?

Yeah, I was always under the impression it was a ATK ad.  

[pippin]

Jim - 9/5/2007  12:39 PM

pippin - 10/5/2007  4:50 AM

Jim - 6/5/2007  3:45 AM

CFE - 6/5/2007  8:41 PM

In DIRECT, do the SRB's still impact within the range of the recovery ships?  NASA would feel this is very important, although I favor expendable SRB's with filament-wound casings.

The whole reason for SRB's are the existing casings and recovery of the boosters.   filament-wound casings negate the ESAS reasoning for using the current SRB's, which BTW have been the only boosters to kill a crew.

The Boosters did not kill the Crew. The missing escape system did.

Too quick for any abort system to react

I thought the crew was still alive after the explosion. That would make for a goot time for the abort system to react. Didn't they install something for this case after Challenger?

[sandrot]

Jim - 10/5/2007  6:39 AM

pippin - 10/5/2007  4:50 AM
The Boosters did not kill the Crew. The missing escape system did.

Too quick for any abort system to react

Isn't the whole point of LAS to escape from a failing booster? The crew was alive after the explosion if I'm not wrong.

[clongton]

Wolverine - 10/5/2007  8:13 AM

Chris Bergin - 10/5/2007  8:03 AM

Moved from another thread, but ATK seem to have been really cheeky and set up a page of their own, using what Dr Stanley said on his Q&A about Direct on here on one of their own pages! Very one sided too.

http://www.safesimplesoon.com/mythbusters2.htm

Crikey. This is an actual official ATK site, right?

Yeah, I was always under the impression it was a ATK ad.  

ATK has put up a website designed to discredit the DIRECT concept, essentially by restating some of Doug Stanley’s observations on DIRECT v1. One wonders though, why they waited so long to respond, only to echo Dr Stanley.

1. The opening statement is incorrect. DIRECT v1 did not advocate a baseline design of five RS-68 R engines as ATK states; it used three. They are simply incorrect on that point.

2. All of the other Stanley observations are addressed in version 2:
....a. RS-68 regen: Version 2 uses the stock RS-68 Standard, only man-rated
....b. Propellant load: Version 2 used the standard ET tank, same propellant load
....c. “heavy-lift vehicle ... lunar solution costs [more]": Version 2 uses a different approach. Result: lower cost
....d. All of the remaining objections focused attention on the Ares-I, not on DIRECT. The Ares-I is not a subject in version 2. Direct version 2 deals with the Direct Alternative Architecture, and the Jupiter family of launch vehicles. The Jupiter launch vehicle will stand or fall on its OWN merits.

3. In short, ATK’s web site is focusing its efforts on a launch architecture that no longer exists. Direct v2, while looking similar, is completely new. Every one of Dr Stanley’s observations has been addressed seriously in its creation, and in fact, formed the environment in which the revision was created.

4. Expect an announcement shortly.