Re: NASA's grand plan to revive human exploration...

[gaetanomarano]

<br />"...does the craft returning from moon, or mars, break into Earth orbit..."<br /><br /><br />with its own (replaceable or refuelable) rocket engine in a joined service module (like Apollo)<br /><br />for more efficiency (efficiency is not a bad-word when it is useful!) may be a two-stage module, the first to go moon orbit, the second (little) to return to earth orbit<br /><br />

 

[tap_sa]

<font color="yellow">"with its own (replaceable or refuelable) rocket engine in a joined service module "</font><br /><br />Have you <i>any</i> idea how much bigger service module you'd need to make the necessary extra deltav happen? And how much bigger TLI stage that would mean? And how much bigger HLV that would require?

 

[dobbins]

"with its own (replaceable or refuelable) rocket engine in a joined service module (like Apollo) "<br /><br />Engines need fuel, and a considerable ammount of it to lose the excess 8,000 MPH that is built up during a return from the Moon. You are talking about a Module that would have to be a large a rocket that would be needed to launch the vehicle into a suborbital flight from the Earth.<br /><br />The large mass of this extra rocket sized Service Module in turn requires an even more powerful launcher to send it on it's way to the Moon.<br />

 

[gaetanomarano]

<br />"...how much bigger service module..."<br /><br /><br />you wrong<br /><br />1st: because with a 125tons rocket we can launch what we want in one or multiple launches<br /><br />2nd: great part of "weight" will not be sent at each mission: lunar vehicle, service module, etc. will be REUSABLE, we need to send in space only first stage, a LEM2, lunar vehicle resupply and service module refuel (it is an ISS-like work, nothing difficult or strange, ask NASA) <br /><br /><br />

 

[gaetanomarano]

"...an even more powerful launcher..."<br /><br />no, because some modules will be reusable<br /><br />also, we can use multiple launch if necessary to have a better mission<br /><br />if you want that astronauts remain on the moon more than a (mere) week, you need multiple hardware launches<br /><br />the lunar vehicle don't need to be like a 747, only better than capsule! (and more efficient for this "specific" purpose that don't require shields, parachutes, etc. for earth reentry)<br /><br />

 

[dobbins]

This may come as a surprise to you, but NASA hasn't found the leprechaun's pot of gold at the end of the rainbow.<br /><br />They do NOT have unlimited funding to do a half dozen launches for a mission that only requires one with realistic engineering.<br /><br />It costs money to do multiple launches, lots of it.<br /><br />

 

[gaetanomarano]

"...do NOT have unlimited funding..."<br /><br /><br />you know that the main critic about Apollo-SaturnV mission was that NOTHING WAS REUSABLE<br /><br />of a 100+ mt. very expensive rocket, only a little (not reusable) 3 mt. capsule return to earth<br /><br />Shuttle was designed FIRST to be 80% reusable, it was a very great idea in respect of Apollo-SaturnV that become a "bad" idea only after (and due to) inflations, growing of service costs, etc.<br /><br />the CEV-SDLV, with only two reusable SRBs and a (I don't think) reusable capsule, is NOT a great progress over Apollo-SaturnV!<br /><br />if part of modules used will be reusable the total cost will be LESS than an Apollo-like mission (or will be the same but with a better mission)<br /><br />you know that the first ideas of lunar mission was to use ONE vehicle to do all<br /><br />but that "science-fiction" version was changed with Von Braun's idea of mutiple specialized vehicles<br /><br />I think that in next 10 years NASA will change the announced (5% reusable hardware) lunar mission architecture and will use an architecture that will be so innovative in respect of Apollo as much Apollo was in respect to early science-fiction-like lunar missions ideas<br /><br /><br /><br />"...It costs money to do multiple launches, lots of it..."<br /><br />I think that "single launches" with nothing reusable will cost MUCH MORE than multiple launches with 50% or more hardware reusable<br /><br />remember that caspule, vehicle, LEMs, ISS modules, etc. are much compelx and costly than a rocket tank... so, if use multiple launches (losing a some engine and tanks) but save and reuse many times the most expensive and sophisticated modules, we will SAVE VERY MUCH money in respect of a "save-the-capsule-only" Apollo-like architecture!<br /><br />

 

[radarredux]

> <i><font color="yellow">how will this specialized vehicle break into LEO? It has to do that in order to allow the passengers transfer from it to your spaceplanes for returning to Earth.</font>/i><br /><br />Stepping into the middle of a discussion is always dangerous, but here goes... splat.<br /><br /><b><font color="yellow">Scenario 1:</font>/b> Use the Earth's atmosphere for aerocapture. This is what t/Space proposes for their vacuum-only CEV supporting a LEO to Lunar surface circuit. In LEO, the crew transfers to the CXV which is specialized for trips between Earth surface and LEO.<br /><br /><b><font color="yellow">Scenario 2:</font>/b> Never enter LEO. This would be more useful for long-haul trips (e.g., between Earth and Mars) than short trips to the Moon. The "planet transfer vehicle" (PTV (tm)) would be a good sized vehicle that run continuous orbits between Mars and Earth. As the PTV approaches Earth, a tiny "Earth Transfer Vehicle" (ETV) runs out to the PTV, matches orbit, docks, transfers a new crew from Earth to the PTV and the return crew from Mars back to the ETV. The ETV undocks, fires rockets, and returns to Earth.<br /><br />The keys to this plan are:<br /><ul type="square"><li>The PTV is large and spacious to support crews for long voyages.<li>Once placed in a Earth-Mars orbit, the PTV doesn't need much delta V. So, there is an expensive upfront cost to get a large PTV up there and then into the Earth-Mars orbit, but then costs are low.<li>The PTV makes extensive use of recycling system (air, water, food, etc.), so it is largely a self-contained environment. Only minimal amount of consumables need to be added during each orbit.<li>The ETV is mostly rocket and fuel (prop) to support the large delta V necessary to go out and match the PTV's orbit and return to Earth.<li>The ETV has very cramped crew quarters; the crew is expected to only use it for the short journey to the PTV (or alternatively from the PT</li></li></li></li></li></ul></b></b></i>

 

[barrykirk]

Let's look at conjectural space tourism company a couple of years down the road.<br /><br />Assume that the only launch tech available is pure rockets. No fancy alternate stuff.<br /><br />Company A uses a lifting body/winged approach for earth to LEO and return.<br /><br />Company B uses a capsule approach for earth to LEO and return.<br /><br /><br />Assuming all other things are equal, what would be the difference in ticket costs for booking on Company A versus Company B?<br /><br />I suspect that tickets on Company B will be considerably less expensive.<br /><br />Which company will have more bookings?

 

[publiusr]

The 'reusability crap is just that. We've tried that before. EELV would give us the same ISS assembly delays. It is time to support HLLV.

 

[tap_sa]

<font color="yellow">"Scenario 1: Use the Earth's atmosphere for aerocapture. "</font><br /><br />I got the impression that in gaetanomarano's world aerobraking is a no-no because, and I quote, 'future space missions must be "better and safer" NOT "the most efficient possible" ' <img src="/images/icons/wink.gif" />

 

[gaetanomarano]

<br />"...Which company will have more bookings?..."<br /><br />"A"<br /><br />because, with the same technology and experience, will be made 10, 20, 50, 100 passengers spaceplanes (in 2020 up, of course), while a capsule may remain in the ten-passengers range<br /><br />if both will exists in future, capsule will be like a (costly but exciting) executive-jet, while, the 100 seats spaceplane, will be the "Ryanair-space-discount" plane!<br />

 

[gaetanomarano]

<br /><br />"...aerobraking..."<br /><br />if NASA will think useful some "aerobraking" will use it<br /><br />my opinion is that costly modules must remain in earth orbit to be reused many times, instead of launch (and burn) all modules<br /><br />starting from this (efficient) principle, NASA may use the technology they think better and reliable<br /><br />

 

[barrykirk]

Here is a copy of the bigelow prize rules.<br /><br />Ten Primary Rules of the Competition <br /><br />1. The Spacecraft must reach a minimum altitude of 400 km (approx. 250 miles); <br /><br />2. The Spacecraft must reach a minimum velocity sufficient to complete two (2) full orbits at altitude before returning safely to Earth; <br /><br />3. The Spacecraft must carry no less than a crew of five (5) people; <br /><br />4. The Spacecraft must dock or demonstrate its ability to dock with a Bigelow Aerospace inflatable space habitat and be capable of remaining on station for at least six (6) months; <br /><br />5. The Spacecraft must perform two (2) consecutive, safe and successful orbital missions within a period of sixty (60) calendar days, subject to Government regulations; <br /><br />6. No more than twenty percent (20%) of the Spacecraft may be composed of expendable hardware (the term 'Spacecraft' encompasses the launch vehicle in its entirety, including but not limited to, any and all fuel tanks, external rockets, carrier craft, and boosters); <br /><br />7. The contestant must be domiciled in the United States of America; <br /><br />8. The Contestant must have its principal place of business in the United States of America; <br /><br />9. The Competitor must not accept or utilize Government development funding related to this Contest of any kind, nor shall there be any Government development funding related to this Contest of any kind, nor shall there be any Government ownership of the Competitor. Using Government test and launch facilities shall be permitted; and <br /><br />10. The Spacecraft must complete two (2) missions safely and successfully, with all five (5) crew members aboard for the second qualifying flight before the competition's deadline of January 10, 2010. <br /><br /><br />The tricky part is the no more than 20% expendable hardware part.<br /><br />Could a space-x falcon-9 with the 5.2 meter fairing do the job? Internal diameter inside the fairing is 4.6 meters and p

 

[nacnud]

Believe it or not it is better for the environment and cheaper (less energy used in manufacture etc) to use throw away paper plates than to reuse china plates 100s of times.<br /><br />Reusability isn't a panacea for cost reductions.<br />

 

[gaetanomarano]

<br />"...Reusability isn't a panacea..."<br /><br /><br />I agree, but there are thousands things we reuse thousands times without problems!<br /><br />why build ONLY the (very expensive and hi tech) space modules to be used like a condom...?<br /><br /><br /><br />

 

[barrykirk]

reusable condoms? I'll pass

 

[drwayne]

I wonder what the definition of expendible is. Apollo heat shields were in principle reusable a number of times, they were quite overspecified for the requirements.<br /><br />Wayne<br /><br />Given the rate that I would require condoms these days, reusability is not a problem - the next use would be in ... ahhh forget it.... <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[barrykirk]

I also suffer from a low launch rate, but at least the wife is re-usable....<br /><br />Maybe, because the wife is re-usable i have such a low launch rate....<br /><br />LOL

 

[dobbins]

Reusable spacecraft are like cigarette lighters that cost 5 dollars to have them refilled. It's cheaper to just go pay a dollar for a disposable Bic lighter.<br />

 

[drwayne]

I am sure that my wife would volunteer that I am unusable....<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[gaetanomarano]

<br /><br />"...reusable condoms? I'll pass..."<br /><br /><br />my post is clear... but I explain...<br /><br /><br />very expensive (non reusable) CEV-LEM2-SDLV = (not reusable) condom...<br /><br />reusable modules = cars, TVs, airplanes, etc. etc. ect. etc.<br /><br />the proposed NASA lunar missions "vision" is (not reusable) condom-like<br /><br />now, do you understand?<br /><br />

 

[tap_sa]

Perhaps you should try those pills that raise specific impulse.

 

[gaetanomarano]

<br /><br />"...cigarette lighters..."<br /><br /><br />a space module don't costs like a cigarette lighter...<br /><br /><br />burn it after each mission is like dismantle and destroy a 747 after each flight!<br /><br />

 

[drwayne]

Maybe I need a booster shot...<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>