OSP: Capsule v. Wings - if you had to choose right now

dicktice · 2003-11-30 10:02:29

I think that any sort of rotating tether system is still a distant technology if it is possible at all. just can't pull the plug.

No, no--I was referring to orbital transfer tethers, anchored e.g. at the ISS with a weak-link which can be broken after reaching Earth-escape velocity.

dicktice · 2003-11-30 10:23:38

I pretty much agree with the rest of your post, except that flying a lift body or winged ship back down is somewhat more delicate than the "sledgehammer" capsule aproach. Shuttle has done a marvelous job, though probobly no true lift body or winged craft will meet Nasa's "dead stick" requirement for surviveable re-entry without getting pretty heavy... I think Nasa ought to have its head examined for safety-parinoia over this one. If you don't have power, then chances are you are hosed anyway.

I certainly agree and think, after refueling in space wherever the fuel has been cached, rocket-powered orbital speed reduction eventually will be adopted as the way to (1) slow down to less than LEO velocity, even approaching from the Moon, until hypersonic speed below airframe-skin detrimental heating is reached, and (2) gradually reduce the angle of attack until subsonic speed allows power-assisted gliding flyback to land, and (3) deplane from the OSP in a civilized fashion.

Ad Astra · 2003-11-30 14:43:18

I wouldn't put too much stock in what Lunex says--it was pre-Apollo, and written before any of the lifting bodies (HL-10, M2-F2) were built! A capsule is the only good way we have for directly returning to earth from beyond LEO.

But that's not to say that OSP should go beyond LEO. Eventually we should build an interplanetary transportation system, where dedicated shuttles transfer humans between earth and either the moon or Mars. They would rendezvous with a space station or an OSP in LEO at the beginning and end of the mission. Maybe that is what NASA should say when justifying to Congress how OSP will fit into the broader space exploration plan.

A lifting body OSP, confined to earth orbit, is the best design solution for ISS access and access to polar orbit. The lower heating and decelerations, the lack of military intervention to recover the crew, and the increased cross range have all been cited as benefits. This cross range is very important for polar missions because a capsule wouldn't have enough velocity to fly east or west to a recovery site.

Congress has delayed OSP, and I don't expect to see that change until the new national space policy is announced. If an Apollo redux is proposed, OSP will morph into an effort at building a new capsule. If the policy is truly aimed at giving NASA options to explore the solar system, OSP will be the first and final vehicle for the astronauts on their journey.

RobS · 2003-11-30 15:59:05

I suppose a lifting body able to return from the moon will eventually be possible, but the experts have generally felt it wasn't practical--so I gather. And GCNRevenger, wasn't that picture you showed us on the web from 1961? I wonder whether artistic renderings from 1961 can be taken as reliable evidence.

As for water on the moon, if we're talking about 1% or 5% it is recoverable. The argument that the polar regolith has less water in it than concrete--which Zubrin is fond of saying--strikes me as potentially misleading. The regolith water would probably be disseminated as ice in loose particles, not as chemically bound molecules in a hard substance that one must crush to use.

But even if water isn't available on the moon, we know oxygen is, and hydrogen/oxygen fuel is only 1/9 hydrogen by mass. One could launch a tank of hydrogen on an EELV, total mass 25 tonnes, consisting of about 6 tonnes of tank, 5 tonnes of xenon propellant, and 14 tonnes of liquid hydrogen, dock to a solar-electric vehicle, and push the hydrogen to the lagrange point or even into low lunar orbit. There a lunar-based vehicle with 15 tonnes of liquid oxygen would dock with it and land it on the lunar surface, using up about 1.5 tonnes of hydrogen on the way down. You'd have to reserve another 3 or 4 tonnes for the trip up to get the next hydrogen shipment, but you'd still have about 8 tonnes for landing people and cargo, and 8 tonnes of hydrogen burns 64 tonnes of oxygen, so it would go a long way. If you had a SDV or something larger than an EELV, the efficiency would be even better because the mass of the tanks would be a smaller percentage.

I haven't checked the Romance to Reality website, but it probably has plans for using lunar oxygen with imported hydrogen. They were the standard assumption in the 1970s and 1980s.

I suspect the moon is the next destination, with or without lunar water. But we'll see.

-- RobS

GCNRevenger · 2003-11-30 21:46:26

Although it would be nice to not have to import anything to the Moon other than the occasional dose of plant food and maintenance gear, at least initially hydrogen will probobly have to be imported, even if there is a little snow mixed in with the Lunar soil. It will take something of a large industrial operation to harvest it, if it is there in any quantity. In the longer term, with SDV or a "Son of Saturn" making regular though infrequent flights and a large nuclear/ion transfer tug, I guess it would be possible to sustain a Lunar base's hydrogen needs without alot of trouble via a 25-ton payload class Lunar lander and a fuel platform in Lunar and Earth orbit.

An interesting blurb; how about using LOX derrived from Lunar minerals to use as reaction mass in a nuclear thermal engine? The Russians played with Ammonia in their NTR days, and got performance similar to LOX/LH, albeit the engine itself was heavy. Superhot oxygen might have corrosion issues though. Ozone would also be easy to make on the Moon, if you had a use for it.

Yeah, I am starting to lean away from sending OSP to the Moon... make it for launching crews of SIX minimum to a waiting manned transfer and/or lander vehicle fueled up at the LEO fuel platform. It would make OSP easier to build if it wern't tailored for future upgrade options, and Nasa could use some good luck with one of its projects for once. The transfer ship wouldn't have to be anything special, and would probobly be pretty easy to build, since it wouldn't have to be put through anything rougher than Lunar launch.

But, that being said, I think it is possible to harden a lift body enough to return from higher-than-LEO speeds, but that would be alot of trouble that Nasa doesn't need at the moment. I would like to see propulsive capture into LEO be the standard of any Moon-Earth flight with areobraking being a backup.

Anybody have any clue how hard to make or heavy a zero-G hydrogen liquifier would be? With a nuclear ion tug, there would be plenty of electricity to power one.

GCNRevenger · 2003-11-30 21:52:50

Oh, and let me reiterate my very-not-liking of a capsule, for the previously stated reasons which I won't repeat here... Although a capsule is the only PROVEN type of ship that can withstand direct return from the Moon, it is not inherintly the only way.

In any event, this method of returning to Earth would be too expendable... if it wern't for the need to beat the Communists to the Moon ASAP, I would have to label the Apollo architecture as a mistake, since the tiny scale and unreuseability of the system itself helped to hasten the end of manned exploration.

RobS · 2003-11-30 23:24:14

Regarding lunar polar ice, I just created a new thread describing a new report about this subject. It says the best data we have is that the regolith in the permanently shaded areas is 1.6% water. This report suggests a way to make a commercial system to extract lunar water, fly it to LEO, and use it to push satellites from LEO to GEO. It's a 78 page report, very professional, and worthy of serious study.

But rather than deflect this topic, I created a new thread in the interplanetary transportation section to discuss it.

-- RobS

Ad Astra · 2003-12-01 20:32:19

... if it wern't for the need to beat the Communists to the Moon ASAP, I would have to label the Apollo architecture as a mistake, since the tiny scale and unreuseability of the system itself helped to hasten the end of manned exploration.

Yes, Apollo was pretty wasteful and inefficient. Nuclear-thermal rockets would be better than chemical rockets for human travel to the moon, reusable shuttles between earth and lunar orbits would be cheaper than Saturn upper stages, and reusable landers would be better than the throw-away "spider" LEM. Von Braun wanted to put a space station in lunar orbit and push it there with reusable nuclear shuttles. A Dyna-Soar-type shuttle could have serviced the nuclear shuttles and ferried humans to them. Alas, the dream is on hold.

Also, McNamara's cancellation of Dyna Soar in 1963 ended any chance we had of a practical space shuttle. Dyna Soar would have given us realistic expectations (and safer design concepts) for a winged, reusable spacecraft. I feel that if Dyna Soar had succeeded, it would have been followed by a larger Dyna Soar launched on a Saturn V first stage, and perhaps evolved into a totally reusable system.

The forgotten lessons of Apollo and Dyna Soar should not be wasted during OSP. Building a small, winged vehicle should not take nine years and $13 billion. It also gives us the cross range flexibility that capsules lack.

In NASA's first OSP capsule study, the capsule was supposed to splash down close to the west coast in hopes that a helicopter could be there and take the injured crew member to the hospital within 24 hours. It should also be remembered that NASA deemed the Soyuz unsafe for its needs in 1992, but reversed the decision shortly after because Soyuz was a readily-available solution, and because it would please the Russians to do so. Any capsule would carry almost all of Soyuz's weaknesses.

GCNRevenger · 2003-12-01 22:18:19

A capsule could possibly fulfill Nasa's 24-hours-minimum emergency return requirement for the ERV, but only if it carried a substantial amount of storable liquid OMS fuel (no push button and pray solid motor ala X-38). Substantial as in more than EELV could easily haul possibly, and more than a lift body needs to glide to safety definatly.

Hopefully Nasa will not try an "Apollo II just enough to get there" return to the Moon with the technology it has available to it today, which would lead to a capsule... they better get their heads on straight and start thinking about a multi-flight DC-X style Lunar lander and/is-also a cryogenic transfer vehicle for humans and cargo. Cargo could also be moved by Nasa's nifty new giant ion engines powerd by clusters of 100KWe or a 400KWe Prometheous reactor... nessesity is the mother of invention.

SpaceNut · 2019-07-21 16:21:11

Another to fix...

Seems we were looking into the future as the ships that are doing cargo happen to be capsule shaped and one being more like a plane...
But for men we are at a stand still

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#126 2003-11-30 10:02:29

Re: OSP: Capsule v. Wings - if you had to choose right now

#127 2003-11-30 10:23:38

Re: OSP: Capsule v. Wings - if you had to choose right now

#128 2003-11-30 14:43:18

Re: OSP: Capsule v. Wings - if you had to choose right now

#129 2003-11-30 15:59:05

Re: OSP: Capsule v. Wings - if you had to choose right now

#130 2003-11-30 21:46:26

Re: OSP: Capsule v. Wings - if you had to choose right now

#131 2003-11-30 21:52:50

Re: OSP: Capsule v. Wings - if you had to choose right now

#132 2003-11-30 23:24:14

Re: OSP: Capsule v. Wings - if you had to choose right now

#133 2003-12-01 20:32:19

Re: OSP: Capsule v. Wings - if you had to choose right now

#134 2003-12-01 22:18:19

Re: OSP: Capsule v. Wings - if you had to choose right now

#135 2019-07-21 16:21:11

Re: OSP: Capsule v. Wings - if you had to choose right now

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