Dr. Griffin's new architecture

BWhite · 2005-08-13 21:49:22

I propose this thread be about the new architectures that should start flowing out of NASA over the next few weeks.

This website claims to have exclusive info about the new architecture. I offer the link for your review, assessment and enjoyment.

Anyone visit NasaSpaceFlight.com before today?

T.L. James has blogged today's speech by Chris Shank at the Mars Society Convention.

More details as I discover them.

John Creighton · 2005-08-13 23:25:40

I'm sold but it seems to be that all the information is about what resources will be used to get to LEO, with a little bit mentioned about risk and sustainability. The document didn't even say which SDV concept would be used . All it mentioned about lunar architecture is how a larger launch vehicle can reduce risk and all it said about mars architecture is the inline vehicle has options for a mars mission. So it would seem to be just a good presentation of what we already know.

P.S. I would of loved to see Chris Shank's presentation.

Commodore · 2005-08-14 00:27:16

It also said the Lunar lander will look very Apolloishl but land with considerable amounts of equipment, including ISRU stuff. The Orlando Sentnal article gave a figure of 23,500lbs.

I think were jumping the gun a little on that. For the first phase we need several missions of relatively simple scouting missions to test reusable transit and surface LSS and to get a good idea of whats available at at least a dozen sites. The same LSS technologies that enable people to stay on the ISS for months at a time aught to be more than enough to aughment the CEV systems and keep 4 people drinking and breathing for a 2 to 3 week Lunar mission. Combine the Service and Lunar module and land and take off with the whole thing, and leave the Service module in LEO. Launch the CEV with a few small transfer tanks that refill the SM. This way we can funnel more funds into the various surface systems for the next phase.

idiom · 2005-08-14 05:07:06

That first graph makes the Saturn look pretty darned spiffy, bigger payload, wider fairing, no solid boosters and its shorter than the 'magnum' and the 'longfellow'.

Surely the First stage could have a recoverable 'engine pod' or what not. What would a Saturn lift with SRB boosters (lets play keep the shuttle army), could it make 150 or 160 ton?

srmeaney · 2005-08-14 07:41:17

That looks bad. No more space planes and lifting bodies beyond the CEV...

All heavy lift. All waste of resources, all nasty.

The Missile guys win again.

GCNRevenger · 2005-08-14 10:43:40

Hasn't the abject failure of Shuttle program clearly demonstrated that trying to build a really good spaceplane cannot be done on the cheap?

Right now NASA needs all the money they can get, since they'll be propping up Shuttle for a few more years and ISS for another decade, which will cost up to half of NASA's manned spaceflight budget every single year on the average (65% until 2010, 40% thereafter until 2017).

A new Shuttle-II would be the very last thing we need right now, since it would easily absorb >$25Bn and many years to build if we wanted to do it right, and that would just be for the Shuttle, and nothing to put in it or anywhere to fly it to.

Saturn-V, for all its magnificent power, was never very economical since each copy cost about $2.5-3.0Bn each, easily four or five times the worst-case cost for Magnum/Longfellow. I am especially interested by the Longfellow vehicle, since it would use cheaper RS-68 engines instead of expensive SSMEs, but it has probobly already lost out to the political need of retaining SSME personel.

If you were to ring the Saturn-V with Titan-IV type solid rocket engines, it would be able to lift almost four hundred metric tonnes... The G-loading would have been awfully high for passengers, and the reliability wouldn't have been very good however.

Ad Astra · 2005-08-14 14:58:29

The site specifically mentions the development of an "expendable SSME." NASA is going to have to justify why we should redevelop the SSME to be thrown away instead of going with the expendible RS-68. True, the SSME has a higher ISP (~450s vs. 410s,) but it also has lower thrust and a higher parts count.

GCNRevenger · 2005-08-14 20:21:34

The higher Isp might make a big difference for an SDV rocket, since reguardless which configuration is chosen, most of the energy required to get to orbit will still be provided by the boosters and the core stage, with the upper stage (if any) playing a pretty minor role.

Then there is the political bennefit of not having to eliminate ~500-1,000 members of the Shuttle Army however.

Ad Astra · 2005-08-14 22:03:50

The paradox of the Shuttle-SDV program is that improving its efficiency (by using automated processes instead of human labor) will decrease the program's political standing. I must confess to having a personal stake in the shuttle's standing army, as I have friends who work on the program. At the same time, my ultimate loyalty is to the American taxpayer, and I believe that providing them with the best exploration value is our greatest concern.

If the SSME is phased out in favor of RS-68, I suspect that most people who worked on the shuttle's engines would be transferred to work on the SDV engines. Still, this creates a gap of several years between the shuttle's 2010 retirement and the first flight of SDV (which may not occur until 2018, depending on the funding profile. The Stick will hopefully be ready by 2011.)

People who think that SDV will reduce the size of the shuttle army are missing a lot of details. The shuttle's life support people will get reassigned to CEV life support; the shuttle propulsion people will transfer to CEV propulsion and SDV propulsion. Very few positions will be eliminated, and new ones will be created; it's just that the number of people needed to fill those positions might decrease.

BWhite · 2005-08-20 11:23:16

Request for assistance from our rocket scientists. Here is a table posted in a space.com thread.

Comments?

Next, can the genuine rocket scientists here comment on the pros & cons of the SSME -vs- RS-68 -vs- RLX -vs- J2S for the SRB CEV 2nd stage?

= = =

One issue raised in that thread:

"It is possible that changing the expansion ratio of the nozzle will improve performance"
No it is a fact. The closer the exit pressure is to ambient the better the performance.
Of course it does. What I mean is that the additional performance may not be worth the extra cost, bulk and weight.
Take the RL10 for example. The RL10-A4 weighs 168 kg and gets an IpSec of 449 secs. The RL10-B2 has a much larger nozzle -- the largest drop in place carbon nozzle for that matter -- and attains 465 secs. This also increased the weight of the RL-10B2 to 302kg. A huge chunk of the weight of rocket engines is nozzle weight, and when you go to a huge nozzle this can skyrocket very quickly and you reach a point of diminishing returns quite quckly.
IF we increase the IpSec rating of the SSME to 470 secs (up from 453) with everything else being constant payload rating goes up from 19.3 to 21.3 tons. That is a good 2 tons. But how much is the new giant nozzle SSME going to weigh? If weight is gained at the same ratio as we see going from an RL-10A4 to an RL-10B2 then the SSME will weight 2534 kg more (5711 kg), completely negating the payload increase and in fact reducing payload by 500kg. Even if that does not happen... lets say the weight gain is only half that -- 1250 kg. That still leaves a mere 750kg increase in payload; a 750kg increase over 19,300kg. One then has to ask whether that is worth redesigning the SSME, retooling for its manufacturer and recertifiying it for manned flights.

Ad Astra · 2005-08-20 11:47:31

A few comments about the chart:

--RLX is a paper engine until they can build and certify a flight article. Same thing for J-2S, as nobody's demonstrated that it can be put back into production economically.

--I don't know how feasible it is to have 200t and 300t upper stages. Can the booster handle the compressive loads from a heavier upper stage?

--The Isp for RS-68 seems high. 410 sec in a vacuum is more realistic.

Other than that, the chart's pretty comprehensive.

SpaceNut · 2005-08-20 19:00:32

Can anyone tell me what the number under the srb is from the space.com thread?

Also how soon could construction begin for any portion of any of the designs?

I like what I see in all referenced links but wonder how much and how soon contracts could initiate this work?

BWhite · 2005-08-21 10:17:13

Can anyone tell me what the number under the srb is from the space.com thread?
Also how soon could construction begin for any portion of any of the designs?
I like what I see in all referenced links but wonder how much and how soon contracts could initiate this work?

Do you mean "4 seg SRB 100 t upper J2S"

I read that as a four segment solid rocket motor (others have 5 segments) with a 100 ton second stage powered by a J2S engine.

Over at space.com the thought has been expressed that a larger second stage is needed to hold down the first stage gee forces. Place greater mass on top of the SRB and it cannot accelerate as rapidly.

SpaceNut · 2005-08-22 05:41:14

Yup, ok now I see. But I though that the CEV was to be 25T so where is the other 75 and what is it used for?

Also another way to throttle back the gee kick is to open the nozzle opening but I think that adding more useful payload to the upper stage is a good compromise.

GCNRevenger · 2005-08-22 09:36:39

No, the upper stage mass figure is for the upper stage, its engine, and the fuel it carries, not the payload.

publiusr · 2005-08-25 12:40:32

With the four SRBs--it will be able to Loft 160 tonnes--so there is a mars ship right there. The missile guys don't like SDV--they don't want anything bigger than Minuteman III. I for one am quite glad the HLLV crowd is getting respect.

GCNRevenger · 2005-08-25 15:45:57

Well, the missile guys have not had a say in launcher selection since, oh, the end of the Titan-III program.

Shaun Barrett · 2005-08-25 17:42:26

Excuse my ignorance but can anyone give me an idea of the maximum payload to LEO on the most powerful SDV possible - i.e with as many strap-on SRBs as will fit, etc. etc.?
[Not that I'm suggesting it should be built or that it will be necessary or desirable. Just curious, that's all. ]

clark · 2005-08-30 19:52:12

http://www.spaceref.com/news/viewnews.html?id=1059

Dr. Griffin will present:

The spacecraft and systems we will develop will build upon the foundation of the proven designs and technologies used in the Apollo and Space Shuttle programs, while having far greater capability. They will be able to carry larger and heavier cargos into space, allowing more people to remain on the moon for longer periods of time. Even on the initial missions, we will take the entire crew of four astronauts to the surface instead of two, remaining on the surface for a week instead of a few days, while the crew exploration vehicle remains unoccupied in lunar orbit. Going well beyond Apollo, we will have the ability to land and conduct exploration activities anywhere on the moon, including on the far side or in the polar regions.
In our planning, we wanted to ensure that we were designing systems with the maximum possible applicability to future missions to Mars. Nowhere is this more important than for the core heavy-lift transportation system. Knowledgeable analysts are aware that a voyage to Mars will require a spaceship on the order of 500 metric tons, more than half of it fuel, in low Earth orbit. The Shuttle-derived heavy lifter we are developing for missions to the Moon will support the LEO assembly of such a vehicle in a matter of months, with no more than a half-dozen assembly flights, utilizing Launch Complexes 39-A and -B at the Kennedy Space Center.

Buckle up! And enjoy the ride.

Rxke · 2005-08-31 01:29:03

He said they chose for the 125 metric tonne SDV variant.
That's better than the Saturn V, heehee!

Xaliqen · 2005-08-31 03:29:52

I have to say I'm a little bit worried about some of these side-mount SDV options that are still on the table. The only reason I can think of as to why these would even be considered is in order to save cost by not having to modify the VAB and related structures as much. That seems to be a bad rationale, in my opinion, and I certainly hope that the in-line approach wins out.

SpaceNut · 2005-08-31 05:10:53

Another reason for the side mount has to do with the ISS modules mounting that was designed for the cargo bay of the shuttle. If the bays diameter is larger than the external tanks then adding it inline means lots of modifications of the tank.

SpaceNut · 2005-08-31 05:48:39

What ever happen to the 2 nd generation shuttle? Reusable Launch Vehicles (RLV)

GCNRevenger · 2005-08-31 07:41:16

There are only two reasons to build the side-mount Shuttle-C, and neither one of them are good:

-To try and "finish" the ISS, in a supremely expensive and yet another vain attempt to make the ISS worthwhile, which is sure to fail since the station is worthless compared to its fantastic ~$200Bn total cost or the $40-50Bn+ yet to be spent on it even if it were "completed" and tended by CEV/Klipper/ATV.

-To just barely get man to and from the Moon with the smallest possible expenditure despite basically wrecking exploration far from a base, driving up the cost of said base, and dooming the rockets usefulness for Mars.

Either option would severely undermine support for the bigger inline SDV launcher, which has enough power to execute real exploration all over the Lunar surface, heavier payloads to make Moon bases or Mars ships less expensive by reducing the number of launches, and not to mention Shuttle-C's payload envelope is too narrow to carry a Mars ship.

Shuttle-II is exactly where it should be... out of sight and out of mind until AFTER we have some place to fly it to, which is easier built by heavy lift rockets.

RobertDyck · 2005-08-31 08:46:35

We've been through this. The standard Shuttle-C would have a payload envelope the same as the Shuttle orbiter, but it could be replaced by a wider fairing. See Shuttle-C Block II with ASRMs and 10 metre diameter payload fairing.

We need the Moon to test hardware for Mars, that's all. We don't need an extensive lunar exploration program. Apollo explored the Moon, been there done that. We need a single Mars habitat on the Moon as a permanent (or semi-permanent) lunar base, and to test Mars hardware. Lunar exploration can be done from that location. A small CEV can ferry astronauts to and from that lunar base. The small CEV can be a capsule like a Soyuz descent module with descent stage and ascent/return-to-Earth stage. If you really need exploration of a site other than the base, you can include a small load of science instruments in the descent module. Apollo did that with the LM, this architecture simply combines the CM and LM for simplicity. You can further reduce the CEV by producing lunar oxygen for return to Earth, which would demonstrate part of ISPP for Mars but may only be practical at the lunar base. For further arguments I'll refer you to Robert Zubrin's The Case for a Small CEV.

I still think Shuttle LS-A or Shuttle MDC from the 1969 proposals would be better than any recent Shuttle II proposal. But I don't think we need a large shuttle at all right now. Both the Challenger and Columbia investigations recommended separating cargo from crew, we could do that with Shuttle-C and a small space taxi to cary just crew with no cargo.
Shuttle LS-A

Shuttle MDC

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#1 2005-08-13 21:49:22

Re: Dr. Griffin's new architecture

#2 2005-08-13 23:25:40

Re: Dr. Griffin's new architecture

#3 2005-08-14 00:27:16

Re: Dr. Griffin's new architecture

#4 2005-08-14 05:07:06

Re: Dr. Griffin's new architecture

#5 2005-08-14 07:41:17

Re: Dr. Griffin's new architecture

#6 2005-08-14 10:43:40

Re: Dr. Griffin's new architecture

#7 2005-08-14 14:58:29

Re: Dr. Griffin's new architecture

#8 2005-08-14 20:21:34

Re: Dr. Griffin's new architecture

#9 2005-08-14 22:03:50

Re: Dr. Griffin's new architecture

#10 2005-08-20 11:23:16

Re: Dr. Griffin's new architecture

#11 2005-08-20 11:47:31

Re: Dr. Griffin's new architecture

#12 2005-08-20 19:00:32

Re: Dr. Griffin's new architecture

#13 2005-08-21 10:17:13

Re: Dr. Griffin's new architecture

#14 2005-08-22 05:41:14

Re: Dr. Griffin's new architecture

#15 2005-08-22 09:36:39

Re: Dr. Griffin's new architecture

#16 2005-08-25 12:40:32

Re: Dr. Griffin's new architecture

#17 2005-08-25 15:45:57

Re: Dr. Griffin's new architecture

#18 2005-08-25 17:42:26

Re: Dr. Griffin's new architecture

#19 2005-08-30 19:52:12

Re: Dr. Griffin's new architecture

#20 2005-08-31 01:29:03

Re: Dr. Griffin's new architecture

#21 2005-08-31 03:29:52

Re: Dr. Griffin's new architecture

#22 2005-08-31 05:10:53

Re: Dr. Griffin's new architecture

#23 2005-08-31 05:48:39

Re: Dr. Griffin's new architecture

#24 2005-08-31 07:41:16

Re: Dr. Griffin's new architecture

#25 2005-08-31 08:46:35

Re: Dr. Griffin's new architecture

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