Newbie, with opinions on CEV!

[mrmorris]

<font color="yellow">"Yes it does however when you add in the items that are part of the orbiter and not payload (Navigation, attitude control,orbital change engines and prop,docking systems) then the payload is down to the 6,000 pound range at the ISS. "</font><br /><br />I can't believe that. If true -- someone is really screwing up. The CEV is supposed to weigh in at 26 tons -- I'm assuming metric tons, so 26,000 kg. Essentially we're looking to create a cargo-version of the CEV, so a Progress-clone. The stats on the Progress M1 (from Astronautix) are:<br /><br />Progress M1: 7,250 kg -- 2230 kg Cargo (30.7% payload)<br /><br />The stats on the Progress M2 are even better:<br /><br />Progress M2: 13,300 kg. -- 5,700 kg Cargo (42.8% payload)<br /><br />This makes sense, as many required subsystems don't scale up with the mass.<br /><br />If the cargo-based CEV can only lift 6,000kg of cargo for a 26,000kg mass, then its payload fraction would be only 23.1%. That's ridiculous. Even if it is recoverable and has heat/shielding and recovery systems, the fact that it masses twice what the M2 does means that it should be able to <b>at least</b> match the 43% M2 payload fraction for a payload of ~11,000 pounds.

 

[shuttle_rtf]

>Going to the extreme of going with unproven technology should NASA give a propulsion system contract to the British guy who saids he can make rocket fuel from the English boggs?<<br /><br />That's where the UK's Space Program is right now!

 

[gunsandrockets]

"When a CEV crew is on board the payload capability, othere than the crew is only a few hundred pounds."<br /><br />Which CEV design are you refering to? A NASA reference design?<br /><br />Because according to a May issue of AW&ST the Lockheed CEV can carry 5,000 pounds of cargo when manned. And this was the version of the Lockheed CEV designed with an upper mass limit of 20 metric tons under the older CEV specifications. Presumably an unmanned cargo version of the Lockheed CEV under the new mass limit of 25 metric tons would improve the cargo carried to something much greater than 5,000 pounds.<br /><br />http://uplink.space.com/showflat.php?Cat=&Board=missions&Number=224877&fpart=1&PHPSESSID=

 

[grooble]

We have a space program?!?

 

[gunsandrockets]

"While I do love lifting bodies, and Lockheeds design, my main reason is for thier architecture. if you read the two architecture studies back to back, you'll get what I'm talking about."<br /><br />From what I have seen of the Lockheed architecture I like it too. I especially like the principle of working backwards from Mars, as in figuring out a practical architecture for Mars and adjusting it for Lunar operations. But NASA seems as if they are going to follow a different path.<br /><br />From the most recent news about NASA's plans I'm afraid the Moon is the whole focus of the VSE. Rather than spend 5 to 10 billion dollars to develop a shuttle derived HLV, I'd much rather see that money spent to develop nuclear rockets and spent on actual missions lifting cargo with existing launch vehicles.

 

[nyarlathotep]

<font color="yellow">X1, X-15, Spaceship 1 come to mind. Nobody has airdropped with the rotation and parachute method before.</font><br /><br />They dropped a scale model from Burt's Proteus. It worked fine.

 

[soccerguy789]

I was actually mainly looking at the launch architecture. Lockheed, plans a complete lunar "train" or whatever you would call it, at about 140 tons. this is about 1 HLV SDLV and 1 single stick SRB launcher. againdst Beoing at 200+ tons to orbit. They have this extra wheight so that they can have a single stage reusable lunar lander, but they don't plan to reuse it in the forseeable future! this is insane! Lockheed has a lander that ordinarily is 2 stage and disposable, much like the lander in the Apollo era. But once they have ISRU set up and producing propellant, they plan to be able to reuse the lander, so no money is wasted. Thats what I like about it. As far as going to mars, the architecture studies barely touch on it, but I like the idea of using the SDLV HLV to launch a massive SEP (solar electric propulsion) unit into obit, and use that not only to move betweeb earth and Mars, but whemn it's not being used for mars, use it to transport cargo on the cheap to and from a moon base.

 

[gunsandrockets]

Moon architecture plans<br /><br />I haven't read all that you have about the plans, but from what I have I think there are other reasons in addition to the lander issue that accounts for the superior economy of the Lockheed mass budget.<br /><br />The Lockheed plan is to build a single large equatorial base on the nearside of the moon. Travel from the Earth to the moon uses LLOR flight architecture. This is the most efficient way to move mass from the Earth to the moon. <br /><br />The Boeing plan includes landings at the south pole. Reaching such a low lattitude on the moon is more difficult. To get there Boeing plans on using the EML-1 region as a way station and docking point.<br /><br />The Lockheed lunar plan is a reflection of the Mars plan in the sense that a large central base from which exploration is conducted and to which crew can abort to is a very logical plan for Mars operations.<br /><br />But the Boeing plan of flights to the south pole of the moon (and therefore use of EML-1) seems to be the way NASA is leaning. News of the NASA decision leaked out so far mention flights to much greater lattitudes of the moon compared to the Apollo missions. <br /><br />One plus for using EML-1 is it would ease use of the ISS when traveling to the moon.

 

[gunsandrockets]

" As far as going to mars, ... I like the idea of using the SDLV HLV to launch a massive SEP (solar electric propulsion) unit into obit, and use that not only to move betweeb earth and Mars, but whemn it's not being used for mars, use it to transport cargo on the cheap to and from a moon base. "<br /><br />For a cargo tug I prefer a nuclear-electric over a solar-electric rocket. Then you wouldn't need a HLV to put the tug into LEO and the tug's cargo fraction would improve tremendously. The more compact size of a nuclear-electric tug might even allow design for aerocapture at Mars.

 

[soccerguy789]

Well, the polar base is nice, because it puts you close to any proposed source of H2O. Lockheed included plans about what it would do for polar landings, I'm wondering about this leek you are talking about though. What did it all say?

 

[gunsandrockets]

"Well, the polar base is nice, because it puts you close to any proposed source of H2O."<br /><br />Assuming the water is there. There is a mass penalty to be paid for polar landings compared to equatorial landings when travelling from the Earth to the moon.<br /><br /><br />" Lockheed included plans about what it would do for polar landings,"<br /><br />So far as I know, rovers and hoppers operating from the equatorial moon base would conduct exploration of rest of the moon.<br /><br /><br />"I'm wondering about this leek you are talking about though. What did it all say?"<br /><br /><br />Just the news reports that have come out recently comparing the new NASA plan to the old Apollo architecture. That is where I've read mention of moon landings at greater lattitudes. I'm guessing about use of EML-1; it's possible NASA plans to land at greater latitudes of the moon using LLRO and just burning a lot more fuel instead.

 

[rfoshaug]

"There is a mass penalty to be paid for polar landings compared to equatorial landings when travelling from the Earth to the moon."<br /><br />I'm not so sure. I'm not at all an expert in these things, but please hear me out in my theory... <br /><br />I mean, for the Trans Lunar Injection burn, it shouldn't be much more energy consuming to aim for a point just over the north pole of the moon than aiming at at point just to the east of the moon (Apollo style) as seen from Earth. And with the inclination of the low earth orbit you get from a due-east launch from KSC, you should have plenty of options on the angle you leave LEO in - depending on where you are in your inclined orbit when you do the Trans Lunar Injection burn. It should be all about timing the burn at the correct point in LEO (and of course timing the mission so that the Moon is in the right part of the sky).<br /><br />When you get to the moon, you'd still have to do a slow-down burn to get captured in lunar orbit, and that should also require about the same amount of energy, wouldn't it?<br /><br />On Earth, launches and landings are most efficiently performed heading East, as the Earth's rotation gives you a lot of speed for free that way. But as the Moon has a very slow rotation, you don't have a big penalty if you don't approach your landing site heading east. In fact, if I remember correctly, all the Apollo missions approached the moon on the "left side" as seen from the Northern hemisphere on Earth, circled past the far side, and landed facing local West with the sun behind them during a waxing moon. So they actually landed in the opposite direction of the moon's rotation.<br /><br />Shouldn't this mean that the energy required is more or less the same for a polar approach as it is for an equatorial approach? Or am I missing something here? <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[vt_hokie]

This is basically turning into what I figured it would - a less ambitious, more drawn out Apollo program, with no real plans to go to Mars and no technology that would be directly applicable to future Mars missions. <br /><br />Using chemical propulsion, what's the likely transit time to Mars? 6 months under a best case scenario? That means a mission of over a year in total duration, with no means of sending spare parts, no Progress resupply flights, etc. There will be the radiation issue, which will be made worse by solar flares. This isn't like ISS, or even lunar flights. I guess the radiation issue exists for lunar missions, but we're talking about a couple of weeks vs. a year or more.

 

[john_316]

If you want to goto Mars on the cheap that is the route they will take...<br /><br />But to do it right requires Nuclear Gas Core or Solid Core Rocket and a less than 6 month journey to the planet and simular back...<br /><br /><img src="/images/icons/smile.gif" /><br />