NEW NASA HLV PLAN LOOKS GOOD FOR NUKES IN SPACE

Date: Jul 4, 2005

NEW NASA HLV PLAN LOOKS GOOD FOR NUKES IN SPACE

Date: Jul 5, 2005

I too am pleased with what Mike Griffin has done. And from what I've heard, he's a good pal of Robert Zubrin.

It seems el Luna and Mars are getting closer by each second.

Date: Jul 5, 2005

I've been an advocate of Space Shuttle Derived HLV for a long time. It allows the best possible comibination of hardware use as well as reatining important infrastructure.

One important observation though, and this was something that I've learned from reading some of Homer Hickham's (the author of the Rocket Boys) fine books: NASA has realized that it is dangerous to assemble SRB's in the Vehicle Assembly Building. Previously, when Apollo stages were assembed in the VAB they were basically inert (with the exception of the linear destruct charges needed for range safety;) propellants and the pressurazation gasses were almost all loaded on the pad after the assembled vehicle arrived at the launch site.

This is not the case with the SRB's, as each segment contains the propellant for that section. The assembled SRB stack is live and contains all the necessary propellant, ignition squibs and destruct charges. To date, no accident has ever occured involving the SRB's within the confines of the building. It is a concern enough that apparently NASA has moved many vital program specific sections out of the VAB into other dispersed areas. Should an SRB inadvertantly ignite within the building, it is doubtful that anyone would get out alive at all--destruction of the VAB would be almost entirely assured. This is a concern of mine as well--should the SDHLV variant become a reality, serious and careful thought needs to be given to expanding and compartmentalizing vehicle assembly. Of course, additional infrastructure such as this would of course incur substantial additional cost, but safety not only for the crews who work on these vehicles but for the continued survival of the overall program is probably worth the effort. It should be fairly straight forward to create a system whereby 'stacks' of SRB's could be moved as a unit on a portable launch pad to an area where the liquid fueld core stage is 'plunked' down between them. This is essentially how space shuttles are assembled.

The more I think about it, really just replacing the SRB's with a reusable liquid booster of nearly identical footprint and configuration as a direct replacement for the SRB's is probably the way to go. When I was in highschool, I looked at an all liquid booser replacement for space shuttle use (this was right after the space shuttle Challenger exploded in 1986!) and came up with something
which probably wouldn't work -- mechanically anyway because the intertank would be too weak -- but it was a booster with about 30% more diameter than a conventional SRB but with identical length. It burned liquid oxygen and ethyl alcohol and used a 4 chamber cluster engine at the base. It would deliver slightly more impulse than a standard SRB because the Isp would have been slightly higher. I used it as a subject for my drafting class--which got blank stares from my classmates and my instructor. But I learned that an all liquid replacement for the SRB is not an insurmountable obstacle and has many advantages. The Russians have used liquid boosters for years with good success.

Still, all in all, I like the SDHLV concept. It is the way to recycle as much of the good things about the shuttle that can be used so that we aren't "...throwing the baby out with the bath water..." so to speak.

Date: Jul 5, 2005

I forgot to comment on Bruce's observation about the pie. Your are righter than perhaps you know.

The Federal Budget has been a bone of contention for a long time--decades in fact. The conlusion I have come to is that the only way to increase funds for space projects, is by increaing funding to all federal projects. And the only way to achieve that is by stimulating enough economic growth to automatically increase government revenues by default (from taxes generating by consumer spending and payroll taxes.) And the only way to achieve that is by applying what I call a Vectored Spending approach to the federal budget: as an inherent philosophy to prioritize spending that actually stimulates economic growth in high technology sectors-- the highest value added sectors of the economy. It seems ironic that to solve the problems of the few, one must address all of the problems at large. Which seems impossible--it is a conundrum!

Still, it concerns me a great deal that the US has no coherent Energy Independence Policy (despite what Mr. Bush has publicly stated,) and we are litterally funneling hundreds of billions of dollars overseas to Middle Eastern countries who do not have our own best interests in mind! So, it seems much more logical to try to spend that money domestically--and who knows, perhaps space research could infact end up solving our energy problems. Solar power sattelites; nuclear pebble bed reactors; or perhaps something far more exotic and powerful await us. We won't know until we spend money on research and development.

In the meantime, big steps are being taken; progress is being made; and Mike Griffin sounds like he has a firm hand on the helm of NASA.

Date: Jul 5, 2005

What NEW NASA HLV PLAN ?

Has there been an official release of the NASA study ?

Please indicate what the discussion is about. Thnx.

Date: Jul 5, 2005

Oops...Sorry. "NASA new/old HLV PLAN" is just a name I give. Most of what has been reported in the media is gossip. I guess it will be announced at the AIAA JPC conference in Arizona this month. Just have to wait till offical NASA announcement and explainations.

The issue

Date: Jul 6, 2005

Here is a very nice write up at Space News:

http://space.com/spacenews/050704_business_monday.html

Here is a quote from the article:

According to this source, key elements of the lunar exploration architecture are coming into focus. For example:

* The CEV would be a reusable capsule capable of carrying four passengers to the Moon.
* NASA would use a three-person version of the CEV capsule to ferry astronauts to and from the international space station three times a year.
* An unmanned version of the CEV would be used as a cargo carrier, conducting three space station resupply missions a year.
* Both the CEV launcher and the heavy-lifter would be shuttle-derived and cost about $3 billion a year once in service.
* The CEV would launch atop a single solid-rocket booster whose design is virtually the same as those that help lift the space shuttle off the launch pad.
* The heavy-lift vehicle initially would be sized to lift 100 metric tons into orbit for Moon missions but could evolve to loft 120 metric tons for Mars missions.

Poster's Note: It sounds like with Mike Griffin in the lead, shuttle derived HLLV is not a dead concept. I think it makes sense to use as much of the infrastructure that is already there--than to create a whole new infrastructure from scratch. Jaro, I'm slowly warming to the notion of a CEV mounted atop a modified shuttle SRB. It could be done. I just can't help but think it still looks a little too much like a giant version of a WWII German Potato Masher!

Date: Jul 6, 2005

You mean "panzer faust" ? (literal translation: tank fist)

Date: Jul 6, 2005

Nope, I believe he means the german fragmentation grenade. You know, the one with the stick handle and a squat little can at the tip? Actually, they say you could throw them farther than the "pinappple" grenades we use today.

Date: Jul 6, 2005

Lord Flasheart has it right, although the "Panzer Faust" also works. He's also right about Germans being able to chuck them farther than the "Pineapples" the US soldiers had.

Anyways, the CEV/SRB is beginning to look better. I'm still a little skeptical about them puting a crew in it though--but I'm perfectly willing to accept them using it to boost a CEV up to the space station for resupply or maybe using it to toss up a vehicle for docking with a Lunar or Mars ship. Still I only trust those SRB's so far--I'm not sure I'd want to ride one!

I remember going over the specs of the old Saturn 5 first stage, and coming to the realization that the first stage all by itself could actually be used as a single stage to orbit vehicle. It has the mass ratio and mass fraction to achieve the required delta-v. It could carry a small payload to orbit. The only problem is the the burnout acceleration would probably be so high (7.9 million lbs thrust/400000 lbs=20) that at nearly 20 g's the payload might be destroyed, the vehicle might tear itself to pieces, and the payload fairing would in all likelihood collapse under excessive atmospheric load. Still, 2.2 minutes to orbit sounds pretty impressive!

Back on topic, I think a shuttle component derived vehicle makes a lot of sense. Retain the best parts of a modular vehicle, use the infrastructure that is laready there--and build on it from there.

Date: Jul 6, 2005

Whoops, just noticed a spelling mistake of mine. "Pin-apples" aren't exactly proper, so to speak. I guess I shouldn't type so early in the morning without a caffeine-stimulant.

There is the possibility of hybrid-rocket boosters, to replace the SRBs. But designing them could take a while, and if safety is the concern an escape tower works just as effectively.

Date: Jul 7, 2005

And what do you think of the SDHLV using six SSMEs with each (expendable !) launch ?

While I'm all for large lift capacity, using existing infrastructure, etc., this seems like a horrendous waste.

Wouldn't it be cheaper, in such a case, to convert the remaining Shuttles to unmanned flight - i.e. cargo only, with automated landing like Buran - and keep re-using the SSMEs ?

Another problem I have is with the SRB-based crew transfer vehicle capsule ditching in the ocean. Can you picture how terribly antiquated that's going to look, once some of the private suborbital joy-ride outfits start operating their aerospace planes, with return to a runway landing ?? I must admit that I was disapointed when even t/Space-Rutan proposed a CXV with the old-style capsule & ocean ditching. Sure its the safest & lowest cost thing to do, but its also pretty ancient technology by now. At the very least, an X-38-type land recovery ought to be aimed for, IMO.

In an ideal world, the proposed SDHLV should use a recoverable engine pod, and the CXV should be a little lifting-body-type ship with runway landing capability - preferably with the wheel wells on the side opposite the re-entry heat shield.....

Date: Jul 7, 2005

Just because something is ancient does not mean it is obsolete. Reentering the atmosphere and ditching into the ocean works. After all, it was done half-a-century ago with ease.

The Russians/Soviets always reentered over land, and I believe a system of parachutes was used for a slow descent. I'd think astronauts making landfall in Texas or some other state would be much more morale-inducing for the populace than flighted, controlled landings.

Of course, there's always the problem of inhabitation in landing sites...

Anyway, there's no reason NOT to use the water. We have coastal ports and plenty of ships to seek the CEV out from the ocean. The technique is tried and true.

Date: Jul 7, 2005

Ocean splash downs ought to be pretty safe. The ocean provides a fairly nice cushion to land in (it's still a pretty rough ride though!) I am much more concerned with having regular access to space than how it looks. Sure the Space Shuttle has a spectacular launch and a beautiful landing, and sure Rutan's Space Ship One landed just like and airplane too, but these craft will be going 7-10 times faster with between 50 and 100 times the kinetic energy. The constraints posed by flyable hardware by the physics involved is a much stronger imperative than the aesthetics of a flight. Besides, safety, reliablility, and other things have their own aesthetic appeal.

I agree that dumping six or eight SSME's in a flight is awfully wasteful--I think that the engine compartments could be designed to detach and survive a reentry to be recovered later. I would also like to see a switch to the RS-68's used in the Delta 4 Heavies. RS-68's generate 650 kilopounds-force of thrust at sea-level, and 745 klb-f at altitude. They mass about 14560 lb each (about 6 metric tons) which is about twice as heavy as an SSME. What they lack in performance (due to lower chamber pressure) they make up for in reduced compexity and reduced cost. They can also be reused, so the cost gains are increased by creating a recovery system--probably an engine capsule for ocean splashdown and recovery.

And the problem with modyfying the orbiters for remote flight--is that there is absolutely no gain for doing so, on aging systems that will soon be retired anyway. The limited functionality of such a retrofit would never be good enough to allow autonomous docking with the international space station. It's dangerous enough with a Soyuz or Progress module, let alone a 100+ ton behemouth. If something goes even slightly wrong, then two similarly sized masses will be on a terminal collision course with each other--with disastrous and probably fatal circumstances!

The use of capsules for transportation of humans are simpler, ought to be more inherently reliable, and are actually stronger per unit volume than a large aerospace craft because the surface area to volume ratio is larger for a smaller vehicle. They are quite simply not as fragile as a larger spacecraft. The physics of their flight is better understood and more easily modeled than complex hypersonic vehicles.
The space shuttle has served its purpose--it is time for a replacement. I think the CEV are a good interim replacement--but I would like to see another reusable aerospace vehicle take its place eventually. Lockheed's Venture Star was a possibility--but because of the complexities involved with the geometry of winding composite cryogenic tankage, this effort failed. I wonder if something like DC-X could be revived. It seemed to show great promise.

Date: Jul 8, 2005

Oh..! SSME liquid rocket engines are there to insure heavy lift which might include cargo of straight cryogas H2, or O2, Xenon etc. for fuel depots at LEO or other type orbits or Moon.

You still have the option to unbolt engines for Earth reentry to recycle or placement at park orbit or to the moon. Land based fuel manufacturing by nuclear space reactor the ultimate solution using native resource.

I don't object to the old style manned reentry solution, because eventually the winged reentry method will return when better materials are available.

Date: Jul 8, 2005

I don't get this "eventually" bit..... The in-house NASA team that designed, built and drop-tested the X-38 were pretty peeved, as you can imagine, when their funding was cut off, just as they were getting ready to build the real thing (TPS & all), for a drop-test from orbit.

http://www.nasa.gov/centers/dryden/images/content/108714main_X-38_3-view.jpg http://www.nasa.gov/centers/dryden/images/content/108712main_X-38_NB-52B.jpg http://users.dbscorp.net/jmustain/x38.jpg http://www.spaceandtech.com/spacedata/rlvs/rlv-images/X-38_on_chute.jpg

Why not just pick up where they left off -- and get a reasonably modern crew transfer vehicle in the process ?? ....this isn't some far-off Star Trek stuff !

The only problem I can see, is that its not easily adaptable to a launch-abort escape system (i.e. top-mounted rocket).

But that's why I think a t/Space-type air-launch is the better way to go.

Date: Jul 9, 2005

You're right about the X-38, Jaro. I agree: we should resume the program where it left off. Actually, I would like to see multiple, independent space vehicle systems tested and utilized. it's more expensive, but having a 'fall back' method of accessing space with crews ensures that a failure in one system won't cripple the whole program. I posit that it is morally irresponsible to blindly rely on only one method of transportation to access the space station. Bringing the Russians 'onboard' brought the capability of docking with Soyuz and Progress spacecraft. The wisdom of this move is bourn out by the loss of Columbia on February 1, 2003: while the shuttles have been grounded only Soviet space craft have been docking with the station.

Redundancy is an essential part of space operations--including having redundant transportation methods. It's expensive--true; but it is unwise to totally rely on one infrastructure for exclusive access. The value of having a redudant method--perhaps using space capsules, small winged spaceplanes, or both to suppliment other methods of transport will be crucial to having long term, regular to space.

Date: Jul 10, 2005

Space Technology

Shuttle Main Engine Design Remains Exploration Candidate

Aviation Week & Space Technology 07/11/2005, page 59

Craig Covault, Kennedy Space Center

The shuttle's main engines, though old, are not forgotten in the new Exploration Initiative

Rocket Science

The Space Shuttle Main Engine, developed 30 years ago, remains a strong candidate for use in the new Exploration Initiative as part of a shuttle-derived heavy-lift expendable booster.

This is because the Boeing-Rocketdyne man-rated SSME remains the most highly efficient liquid rocket engine ever developed. There are only enough parts for 12-15 existing SSMEs, however, so one NASA option is to reinitiate SSME production to use it as a throw-away, as opposed to a reusable, powerplant for NASA's new heavy-lift booster.

During launch, Discovery's three SSMEs will consume 385,000 gal. of -423F liquid hydrogen and 143,000 gal. of -297F liquid oxygen from the external tank. And these SSMEs will generate the equivalent of 27 million hp., with the total energy released at launch equivalent to the output of 23 Hoover dams.

The overall engine has a "staged" combustion cycle in which oxygen and hydrogen are burned in two preburners, each with their own two turbopumps to drive hydrogen-rich gas into the main combustion chamber. Each SSME generates 392,000 lb. thrust at liftoff with 104% throttle at sea level; while at altitude, in a vacuum, each will yield 500,000 lb. thrust.

http://www.aviationnow.com/media/images/awst_images/large/AW_07_11_2005_208_L.jpg

The engine schematic (above) shows the 4.5-sec. valve sequence required to start each engine with a hydrogen-preburner flow from the left (red side) and oxygen preburner flow from the right (green side) starting at T -6.6 sec. in the countdown. The start of each engine is staggered by 120 millisec.

Starting with the main fuel valve (MFV) "1," five propellant valves are ramped open on a split-second schedule to power up the engine while staying within acceptable temperatures. Three igniters spark combustion until the reaction becomes self-sustaining. This occurs as the fuel preburner valve (FPOV) "3" opens atop the low- and high-speed hydrogen turbopumps and an oxygen preburner valve (OPOV) "4" opens atop the two oxygen turbopumps. These two valves allow propellants in from the external tank at low pressures more comparable to a car tire than a rocket engine. That initial low-pressure flow changes instantly, however, to a hellish mix.

The main oxygen valve (MOV) "5" leading to the primary combustion chamber opens as the propellant preburner valves "6" and "7" cycle to adjust for oscillations. Speed and pressure checks ("8" and "10") keep the engine under control as the hydrogen turbopumps--at 15,800 and 33,900 rpm.--boost the hydrogen fuel flow to 6,515 psi. The hydrogen is split into separate paths--one part to repressurize the hydrogen portion of the external tank, another to cool the nozzle and main combustion chamber, and power the fuel turbine--before flowing into the main chamber.

On the oxygen side, two turbopumps are running at 5,000 rpm. and 22,400 rpm., respectively, to boost the oxygen flow to 4,300 psi. The oxygen is also vectored to several areas, including a cooled flow back to pressurize its portion of the external tank. Other portions go to both preburners as well as to the oxygen turbopumps and the main chamber.

When the hot, high-pressure oxygen and hydrogen flows meet in the middle, they create a 6,000F flow, hotter than the melting point of lead [so ????? ....did he mean boiling point of lead ?], that exits each SSME nozzle at 10,000 mph.

If the three Honeywell computer controllers--sampling each engine's parameters at 50 times per second--detect no problems, the solid boosters will fire at T -0 for liftoff.

Date: Jul 10, 2005

Check out this BS! From market savvy "Launch a Space Program with Rubberbands" crowd.

http://selenianboondocks.blogspot.com/

"Now, being a libertarian, I can't stand the big government contractors, but at least their vehicles exist! It's fairly obvious that they could give better prices if there were more flights. There is already a glut of launch providers in this weight class and general price range. Why does Griffin feel that we need to add a NASA operated competitor to make things even worse? While I'd rather that the US government just leave space launch alone, I'd rather they at least not try to compete with the market and develop their own redundant system when adequate capabilities already exist."

Don't these people understand it's about a robust space program that leads to SPACE TRANSPORTATION and opportunities for everybody. Please... somebody set me straight. When did any national transportation system begin as a commercial amusement ride ?

Whether you're carrying mail cargo, people or science packages they all arrive at a destination you wish to arrive to. In order to make destinations more appealing you have to build them up to make them appealing as a destination to be successful in a market setting. Maybe if these free marketers again, could cop to the clue that it takes all sectors of a countries' economy involved in some form toward robust human exploration a commercialization of space to make it worth a real destination.

Date: Aug 1, 2005

Brucie B. wrote:

Don't these people understand it's about a robust space program that leads to SPACE TRANSPORTATION and opportunities for everybody. Please... somebody set me straight. When did any national transportation system begin as a commercial amusement ride ?

Well, the first passenger railroad in the world was essentially an amusement ride until there was enough of a network to make it useful for transportation. The first airplanes were useful for little but exhibition flying at county fairs. The first cars were toys for the wealthy. Etc, etc.

Date: Aug 2, 2005

Good points. Technologically it's a awful long way from a Wright Flyer to a Boeing 747 (although amazingly both were only 63 years apart!) However, I would expect that because of the physics involved with rockets, that because of the energy and velocity reuirements, space travel will never be as routine as air travel unless we clever monkeys figure out a way to fly without having to rely upon reaction engines! In otherwords, as long as we have to use rockets, we will be limited in our ability to access space. It gets easier and less costly per pound of payload with increasing rocket size--shifting to nuclear will double the propellant efficiency which would achieve a reduction of 1/2 of the size and mass of a vehicle for a given amount of payload. Still, we're talking large vehicles though!