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#76 2003-11-24 17:09:14

dicktice
Member
From: Nova Scotia, Canada
Registered: 2002-11-01
Posts: 1,764

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

Shaun: I'm with you one hundred percent! Hope that's acceptable.

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#77 2003-11-24 18:57:46

Shaun Barrett
Member
From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

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

Sure, Dicktice!
    There are too many people in the SRM camp and too few in the 'sensible' camp!!   :;):

    I accept any help I can get.  smile

    NASA and the other SRM advocates would have us wasting our time and money for years if we let 'em get away with it.


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#78 2003-11-24 20:12:27

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

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

But I've never been convinced that a sample return mission is necessary.

The primary reason for a sample return mission is a technology demonstrator for In-Situ Propellant Production. That is to prove the technology for the Earth Return Vehicle will work on an unmanned mission before committing astronauts to it. However, the last time NASA talked about a sample return mission they cancelled the ISPP portion, then increased the cost to the point that the whole mission was cancelled. This time we have to emphasize the primary mission goal is a technology demonstrator, the Mars samples are only secondary. Once the primary goal is fixed, they can't touch ISPP. It would be nice to analyze a Mars sample with detailed instruments on Earth. What exactly caused the reaction on the Viking instrument? Most people think it was release of superoxides in the regolith but a few people like to debate it. What exactly is the chemical composition so we can design spacesuits and inflatable habitats to endure it without corrosion? We have a very good idea, but it would be nice to verify it. Most important for any sample analysis; how is the hydrogen locked in the soil? Is it permafrost? Is it hydrated minerals? How can we melt it and filter the water so it is sufficiently free of contaminants to be drinkable? Or how can we purify the water to be used for ISPP? We don't know enough about the water to do this yet. We could send a manned mission using Robert Zubrin's ISPP technology, and bring hydrogen from Earth. Then the astronauts could analyze the permafrost when they get there. But it does make a nice excuse to prove ISPP before we send humans.

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#79 2003-11-24 21:29:59

Ad Astra
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Registered: 2003-02-02
Posts: 584

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

The high-end cost figures that I'm hearing for OSP (> $10 bil) are ludicrous.  I think that if we opened the competition to Russian or European firms, there might be some incentive for Boeing and LockMart to cut the fat, even if the foreign designs aren't chosen.  A stripped-down MAKS orbiter or a souped-up Soyuz (or even a Shenzhou) would be a viable OSP.

I also agree that the small solids on the EELV will be necessary.  The most common SRM failures have been on large, segmented SRMs.  This is not the case with the small, monolithic SRMs that burn out rather quickly on the single-core EELVs.  However, these SRMs should be equipped with some system that initiates the abort rockets as soon as gas escapes from the SRM case.

I also argue in favor of a more sophisticated lifting body (X-38 or HL-20) instead of a capsule or lifting cone, bcause a vehicle like OSP will be in use for some time and need room for growth.  With OSP, it will be possible to launch manned polar missions from Vandenberg and do all sorts of interesting things regarding remote sensing and satellite repair. If we regard OSP as simply a way of getting to ISS and back, we will end up with a cheap, dirty capsule.  But if we realize that OSP is the only spaceship we will have for many years, it makes sense to build an expandable system.  That's why the ESA is recommending a Hermes-derived OSP.  You just won't have the room for growth in Boeing's "Son of Apollo" or LockMart's "lifting cone."


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#80 2003-11-25 11:04:17

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

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

The cost estimates to develop OSP are not that insane, since the thing has to be ready in a very short time period all things considerd. Nasa is paying a premium for quality work done in a normally-too-short time frame... Nasa wants a rescue ship in only four or five years. That it isn't to say that it isn't dang high, but its probobly within a few billion of what it really would cost.

There is one way to make OSP light enough to ride on the no-SRB version of Delta... cut the crew size down to two or three. Nasa has mentioned on many occasions at length that this may be an acceptable consequence. Which would be absolutely retarded given the needed flight rate. If anything, OSP should be BIGGER, able to seat or seven and for launching specialty cargo aboard a not-man-rated EELV HLV. Somthing interesting to note on close inspection of LM's lift-cone picture, it only has two hatches above the pilot's stations, Gemini style?

This pathological fixation with making the lightest, smallest vehicle is getting a little silly. We'll never be able to get anywhere beyond sending small teams of elite government-subsidized scientists to "learn stuff" with this kind of thinking. For all the Apollo/Gemini and Soyuz/Zarya advocates, I hate to say it, but given our technology level going with a capsule IS a step backward. Capsules work, but so do flying space ships. And they do it better.

Since whatever ship is built will be the last manned ship of the first third of this century most likly, Nasa should not settle for "good enough;" Shuttle never really achieved its potential since the program was so "politicized" and the Airforce needed a polar orbit spy satelite launcher. X-33 and HL-20 were axed really for lack of mission: HL-20 wasn't needed with the X-38/Soyuz to do CRV and Shuttle for CTV "since Al Gore said so" and X-33 was axed because Lockheed couldn't possibly sell enough satelite launches to make it more profitable than selling expendable Atlas rockets.

At the very least, a four-seat version of HL-20 would be light enough to ride on the Delta Mediums, and a six-seater (albeit a little cramped maybe) is possible if the adapter weight were kept down. I don't think its unreasonable to ask Boeing to tack another pair or two of SRBs to Delta IV for Nasa, they went and made a "super Delta II" for them after all... that would place the Delta IV in the 30,000lbs to ISS range for a six-seater. The only comparable capsule concieved by America is Big Gemini, and it would weigh about the same if it were likewise scaled down 25%, and its service module was expendable.

I also want to give an extra helping of shame to Lockheed, for coming up with the idea of the lifting cone with no wheels and that needs an expendable service/docking module, if the thing seats four at all... If the lift cone design is a consequence of Nasa's safety-nanny-parinoia requirement that OSP be able to re-enter "dead stick," then simply put Nasa's requirement is excessive. Shuttle works just fine in this respect, when it doesn't have pizza-sized holes in its wings.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#81 2003-11-25 11:25:39

Bill White
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Registered: 2001-09-09
Posts: 2,114

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

The cost estimates to develop OSP are not that insane, since the thing has to be ready in a very short time period all things considerd. Nasa is paying a premium for quality work done in a normally-too-short time frame... Nasa wants a rescue ship in only four or five years. That it isn't to say that it isn't dang high, but its probobly within a few billion of what it really would cost.

Had the X-38 project been completed, would there be such urgency to deploy OSP? Has anyone ever given a coherent explanation for =WHY= the X-38 was cancelled?

Soyuz "costs" between $50 million and $100 million per launch, right?  If OSP will cost $1 billion per year to operate (link to come) that equals between 10 and 20 Soyuz launches per year. If the ISS consortium bought Soyuz in bulk (10 or 12 per year) a quantity discount would probably be available.

Buy Soyuz and delay OSP until the right design and the right purpose is clarified.  Why rush a project that will lock NASA into compromises that we will be stuck with for decades?

= = =

PS - I have been browsing the Starsem web site. The Russians are selling Soyuz launches the same way Michael Dell sells personal computers. Retail.  smile

Why is it that the Russians seem better at "doing space" the free market, capitalist way?

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#82 2003-11-25 11:33:33

clark
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Registered: 2001-09-20
Posts: 6,362

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

If I recall, the X-38 was cancelled becuase of multiple problems, but the major one, I think, was the honeycomb composite fuel tank...

Adn the Russians do it better becuase they are hungry.  smile

And I think some are rushing the OSP, precisely because it will lock funding in at home, nice little pork to take home to the congressional district. You buy Soyuz, you don't make jobs here at home.

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#83 2003-11-25 12:09:58

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

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

If I recall, the X-38 was cancelled becuase of multiple problems, but the major one, I think, was the honeycomb composite fuel tank...

Adn the Russians do it better becuase they are hungry.  smile

And I think some are rushing the OSP, precisely because it will lock funding in at home, nice little pork to take home to the congressional district. You buy Soyuz, you don't make jobs here at home.

Its the "tortoise and hare" all over again. America has a 50 year technology lead on the Chinese and 30-40 year technology lead on Soyuz. Yet Soyuz has flown over 1600 successful launches and flies today while frankly superior American technology remains grounded.

The US has superior technology but "so what" if we diddle over who gets which contract?

America needs to set a long term (50 year? 100 year?) objective for space and aim at that goal efficiently. Buy Russian if its more efficient. Design and build at home if its more efficient.

But we must set the finish line far enough away and we must be sure that the faster US hare avoids taking naps or wasteful detours whilst the tortoise plods along. Thats the moral of the fable, right?

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#84 2003-11-25 12:13:51

clark
Member
Registered: 2001-09-20
Posts: 6,362

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

a 50 year goal in the land of the 5 minute attention span?  :laugh:

Are you sure you're not becoming an optimist Bill?

If the US is the hare, and we are talking about the fable, then we should set the finish line closerbig_smile

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#85 2003-11-25 12:20:52

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

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

Sure, Dicktice!
    There are too many people in the SRM camp and too few in the 'sensible' camp!!   :;):

    I accept any help I can get.  smile

    NASA and the other SRM advocates would have us wasting our time and money for years if we let 'em get away with it.

*Erm...sorry to have to ask, Shaun, but what is "SRM"?

I go through a zillion abbreviations a day in my line of work, and after a while they all tend to get clogged up in the old grey matter drain pipes (I was going to ask yesterday, but decided to try and figure it out...went back through the more recent posts -- maybe I'm missing something).

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#86 2003-11-25 12:57:21

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

SRM = Sample Return Mission, a robotic mission to Mars to physicly bring samples back to Earth for study.

We DO need a signifigant long-range goal, I think on the order of 20-25 years would be appropriate, since that would be at least until the end of ISS.

Frankly, flying Soyuz as the "offical" CTV ship to ISS is a bad idea, first because you would need double the launch rate to support a six-man crew with a three-man capsule, second because capsules put a terrible physical strain on the crew, which will hopefully be of persons who are a little less fit than your average military pilot, and simply put America will not send that much money overseas for other people to build space ships, especially when Shuttle is retired. Not to mention how much nicer and less expensive it is to handle a small airplane than it is a space capsule.

X-38 was axed so Nasa could divert its funds to building ISS if memory serves, and since Bill & Al could make more work for Russian missile builders. The X-33 with the bad new composit fuel tank could have worked, but once it became clear that X-33's fuel tank would cost alot of money to redesign, and nobody launches lots of satelites anymore, Lockheed bailed.

Space ships with wings haven't been finished since they are more expensive to build and because there was no need for them. Now there is.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#87 2003-11-25 12:59:11

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

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

If I recall, the X-38 was cancelled becuase of multiple problems, but the major one, I think, was the honeycomb composite fuel tank...

You are thinking of the X-33. The X-38 was cancelled as a budget cut for ISS. Since the goal was simply a Crew Return Vehicle, Soyuz could do the job. NASA tried to salvage X-38 by converting it to an OSP for Europe to be launched on an Ariane V. ESA paid for some development, but ultimately cancelled it. I think Europe wanted a home-grown vehicle. It's ironic considering conversion of X-38 to an OSP was already started.

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#88 2003-11-25 13:02:57

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

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

X-38 was axed so Nasa could divert its funds to building ISS if memory serves. . .

But now we cannot use ISS unless we build OSP, right? ???

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#89 2003-11-25 14:33:51

Ad Astra
Member
Registered: 2003-02-02
Posts: 584

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

There's been some argument about the X-33 and X-38, which I'd like to clarify.  The X-33 was cancelled primarily because it wasn't going to test all the technologies we wanted it to (the composite tanks ruptured in ground testing) and because there was no way the X-33 was going to lead to the shuttle-replacement Venture Star (the fuel fraction was just too hard to reach.)

X-38, on the other hand, had cost overruns, which combined with the overall cost overruns on the ISS made it politically untenable.  When you factor in the reliance on Soyuz that NASA wants to escape and the limited utility of a down-only CRV,  X-38 didn't make sense.  In hindsight, the original X-38 plan was probably better off in the scrap heap because its TPS wasn't a big improvement over the shuttle--still used tiles and possibly RCC on the nose and leading edges, with no metallic or hot-structure TPS.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#90 2003-11-25 15:07:54

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

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

The X-33 was cancelled primarily because it wasn't going to test all the technologies we wanted it to (the composite tanks ruptured in ground testing) and because there was no way the X-33 was going to lead to the shuttle-replacement Venture Star (the fuel fraction was just too hard to reach.)

The only technology problem was the hollow-wall composite tank. They should have stuck to the original design using solid-wall composite tanks. A solid-wall composite tank was used as the LH2 tank on DC-XA, so it was already demonstrated. It was used on DC-XA specifically to test/demonstrate it for X-33. NASA activated the contract clause that said the contractor had to share the cost of any set-back. Lockheed-Martin refused, then their lawyers argued with NASA lawyers for two years. NASA then agreed to use an aluminum tank, but an aluminum tank would not achieve the payload to launch weight ratio required for VentureStar. That's when George W. Bush cancelled X-33. I think he was correct to do so; you can't continue to do business when your primary contractor has no intention of honouring the contract. In fact, after that I wouldn?t let Lockheed-Martin bid on OSP. Don't claim that X-33 or VentureStar were bad designs or that they had technical problems preventing a replacing shuttle. The problem was Lockheed-Martin got greedy.

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#91 2003-11-25 15:25:28

Ad Astra
Member
Registered: 2003-02-02
Posts: 584

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

But how did you expect the Venture Star to achieve the 90% fuel fraction?  Even if every anticipated technology that went into the X-33 worked out, the vehicle still would not have been light enough.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#92 2003-11-25 18:59:41

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

Between Nasa having to send more money Russia's way, who were holding ISS modules "for ransom," and the other crazy costs overruns it is no minor miracle that Nasa has the money to even reach "core complete," which is three crewmen, who wouldn't need the X-38 CRV.

Space technology hasn't sat at an absolute standstill since the Saturn program; the biggest advances have been in materials (obviously). Back in the 60's, a real SSTO was no in the cards... today, building one is in the realm of possibility with the huge improvement in strength-per-weight of composits and advanced metalwork (titanium alloys, for example). Nasa may have been a little over-ambitious with X-33, but its real failing was the contractor couldn't turn a profit with it like they thought when they signed the contract, and weasled out of it. It may not have hit its target performance, but it would have flown.

Though the fate of the X-33 doesn't bare direct relation to the OSP, since it will definatly be launched on an EELV. My big question is, any incarnation of OSP will be able to ride on a Atlas V but its iffy if any incarnation will be able to fly on the Delta IV Medium without extra SRBs or a big compromise somewhere. A scaled-up four seater Soyuz style ship would weigh around 9,000kg which when paird with launch escape equipment and a few hundred kilos of human cargo would put it pretty close to the ~12,000kg weight-to-ISS limit of the Delta IV Mediums. A 75% scale of HL-20 or a third the size of Hermes should get pretty close to 8000kg, which would leave four tons for the adapter/abort equipment. Overall, the lift body would be a little heavier, but not so much that more SRBs can't fix if it becomes an issue.

I will concede that a lifting body ship is harder and more expensive to build, but I think that it really is worth it considering all the benefits.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#93 2003-11-25 19:22:17

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

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

a 50 year goal in the land of the 5 minute attention span?  :laugh:

Are you sure you're not becoming an optimist Bill?

If the US is the hare, and we are talking about the fable, then we should set the finish line closerbig_smile

From Jerry Falwell's perspective, the final finish line is closer than any of us know or expect.  smile

= = =

For the record, I would be very, very pleased if the US funded and deployed a genuine next generation spacecraft.

Soyuz is ancient technology. I was in high school during the Apollo-Soyuz joint mission and I recall a political cartoon showing the Russian cosmonauts in leather space helmets and with chickens floating around in the Soyuz capsule. Yet Soyuz and the Chinese "Son-of-Soyuz" are today the only operational man rated launch platforms.

But. . .

does anyone disagree that form must follow function?

What we want to do with the OSP will determine what design is best. Design must remain a function of purpose.

With the Shuttle/ISS that got reversed. The ISS was designed for modular construction to give the Shuttle something to do. Design dictated purpose which is simply backwards, IMHO. The whole ISS could have been launched on one (2 or 3?) large unmanned boosters - Shuttle C or Energia - one direct throw and the ISS is deployed.

How many shuttle launches have been devoted to ISS assembly? Skylab was enormous!  and needed one launch.

But okay - multiple shuttle launches were needed to maintain employment and technical skills to prevent the withering of the engineering base in the 1970s and 1980s. I am okay with that and perhaps the illogical aspects of shuttle/ISS can be justified for that reason.

= = =

Back on topic - - are we doomed to repeat that same debacle with OSP?

The question: Capsule or wings? My answer: Tell me your budget and what you seek to do with OSP and then I can say which I prefer. Otherwise, all I can say is, it depends.  ???

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#94 2003-11-25 22:44:08

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

The Nasa specs are that it should (though this is possibly optional) four people to the ISS orbit for as low a cost as possible, be safer than either Soyuz or Shuttle and with the ability to re-enter with no active control at all, plus be able to reach a hospital within 24 hours from undocking. Oh yeah, and it has to be able to work completly automaticly, including docking.

The absolute upper limit of its mass is around 20,000kg and preferably less, which is about the maximum payload for the heavy version of the Atlas/Delta rockets. It would be highly desireable for OSP to ride on the single-liquid-engine version of either rocket and with a minimum of solid rocket boosters.

What I think it ought to be able to do...

-Carry a crew of six minimum, preferably seven, so that it could completly replace Soyuz for ISS duty if need be, or for taking down a Shuttle crew if they are stranded in orbit, and to make ferrying larger Mars teams and/or Lunar base crews. Also, place a larger docking hatch to the rear to permit the transfer of ISS science racks in a automated cargo hauler mode for speciality cargo return.

-Be easily modified for medium duration manned flights (two weeks) needed to reach the Moon or a LaGrange point, so OSP could be "just another cargo" out that just happens to carry people. It should likewise be able to depressurize to let the suited crew egress without an airlock. It should also be easily refueled remotely, which would preferably be storables like peroxide and kerosene, for missions based from the Moon or for orbital maneuvering without a stop at Earth.

-Be a lift body style vehicle, capable of cross-ranges similar to that of Shuttle to lower the number of emergency landing sites and be able to land a runway with wheels, to permit soft recovery and ease of handling. This design would be easiest on a injured or deconditioned crew and would minimize the amount of logistics needed for recovery. Just pack the thing in a transport plane and fly it back to the Cape.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#95 2003-11-26 09:01:50

Tyr
Banned
Registered: 2002-09-14
Posts: 83

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

The capsule is leading the winged OSP 14 to 6, but the discussion seems to be promoting a winged or lifting body design.  I agree, design should be led by purpose.  What's the purpose of the ISS?  What's the purpose of our entire manned space program?  I think we are at a crossroads.  NASA must find a goal and aim for it.  Mars is what this website is all about.  What kind of vehicle can help us get to Mars? A capsule or winged/lift body?

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#96 2003-11-26 10:34:14

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

ISS does serve some useful purpose, such as experience for Nasa operating life support systems for extended periods, and if there is no use of advanced high-Isp/high-thrust propulsion then the trip to Mars will be long enough to make deconditioning and radiation exposure a serious concern. ISS was also, I think, supposed to also help Nasa prove that Shuttle was an operational every-day vehicle good for twenty more years, which it has failed miserably in this respect. Also, ISS was built to keep American space contractors in business and to keep Russian rocket scientists from spreading missile tech.

In order to support a useful amount of research, ISS requires some means of crew return for more than three persons and preferably some form of crew transport that can carry more than four as well. Nasa wants this vehicle to be safer than anything flown before, be able to return a crew to a hospital in 24 hours flat, plus be easier and cheaper to fly. A lift body able to glide hypersonicly and land on a runway would be a major advantage to lower the number & complexity of emergency landing sites, it would subject the crew to much less G-force and soft runway landing, and the large surface area combined with its non-ballistic re-entry - albeit areodynamicly more delicate - subjects the heat sheild to lower temperatures save for the hot-spots, permitting re-use. A HL-20 style lift body would also have more internal volume than all but the largest capsule concepts and could possibly mount OMS and abort rockets in the vehicle, eliminating the "service module" and reduce the adapter transstage to a cheap structural mount.

Of course, such a craft would be considerably harder and more expensive to build compared to a capsule, but its worth the trouble.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#97 2003-11-26 10:37:25

clark
Member
Registered: 2001-09-20
Posts: 6,362

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

Capsule.

You don't need wings in space. You need a capsule if you want to go any distance in space, to say, I don't know, maybe the moon...

We have the capability to go anywhere in the world- tell the navy or the army to go pick up the capsule wherever it lands.

Hell, we could practice on pinpoint landing on dry lakebeds in the southwest to get ready for a capsule landing on Mars.

We're not going to have any runways on the Moon or Mars, so what's the point of building a spaceship with wings?

Clip the wings, I say, and we'll fly further and faster.  smile

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#98 2003-11-26 12:38:14

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

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

In order to support a useful amount of research, ISS requires some means of crew return for more than three persons and preferably some form of crew transport that can carry more than four as well. Nasa wants this vehicle to be safer than anything flown before, be able to return a crew to a hospital in 24 hours flat, plus be easier and cheaper to fly.

Okay - Why was X-38 a bad choice for this mission?

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#99 2003-11-26 12:50:08

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

OSP is required to operate as a crew launch and return vehicle, which most certainly does not spend its entire mission in space. Wings are the superior choice for returning to Earth and could be built inherintly more reuseable.

A winged/lift body craft would have such similar capabilities to a capsule in space, that it makes good fiscal sense to only build one, not both. The lift body might be a little heavier with its wheels and stubby fins, but not by alot, probobly to such a small degree that Delta IV modifications would be simple.

Why will a lift body not be able to go beyond LEO and a capsule can? The shape does not matter when there is no air as you have pointed out clark, only structural stresses and mass. A lift body is roomier per-mass too, given the low weight of its heat shield per area. A capsule OSP would be too heavy for a direct flight to the Moon or Lagrange anyway, so any incarnation would have to dock with an orbiting transfer/lander section, and if Nasa builds a dedicated manned Lunar transfer/lander, then a lift body would be even nicer.

Simply "have the army/navy pick them up" is a far stickier proposition than you may think... Unlike Apollo that was equitorial nearly, OSP will be returning from an ISS orbit which covers nearly the entire globe. That increases the number of recovery sites/teams dramaticly. Plus, in order to return to proper medical care in only 24 hours from undock, a capsule would have to carry considerably more fuel for cross-range maneuvering. This is to say nothing of "what if" you have to come down in the water or far from civilization, that it may simply be hard to guarantee 24-hour-to-hospital even with extra fuel. You have to FIND the thing, and fast.

It gets better... a capsule, in any form, by nature of its ballistic trajectory will expose the crew to 3-5G loads. No matter the shape. Thats the way it is. This is not a good thing when flying back deconditioned or injured crewmen; Nasa even considerd changing the seat arrangement on Shuttle to make the return flight easier on them. A injured crewman could quite possibly die... did I mention that HL-20 would have a maximum load of around 1.5G? And no bone-jarring hard landing or finicky landing rockets that can blow up, just wheels which have worked for decades.

Since a lift body also has a much more benign re-entry profile, it can get away with improved Shuttle TPS systems, which should be more than sufficenct with hardening, or could possibly use a METAL shield. Metal heat shield materials have already been tested through re-entry on Shuttle in low heating areas. Check the thing between flights, shine it up, and its ready to go... a far cry from having to half-dismantle a capsule to replace its ablative shield every mission.

A lift body could, in theory, be able to integrate the OMS engines into the craft proper, which would simply negate the need an expendable "service module." That would add up to signifigant savings on every flight, for a modest design/building investment... I think the Air Force is getting ready to test a Peroxide/Kerosene OMS engine for their unmanned space bomber which would be ideal.

Its also easier to handle a ship with built in wheels that integrates horizontally... did I mention that Delta is assembled horizontally? You can tow the thing around with an airport tractor... Lockheed destroyed a communication satelite just trying to turn it over for shipment at their factory.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#100 2003-11-26 12:51:13

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

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

X-38, on the other hand, had cost overruns, which combined with the overall cost overruns on the ISS made it politically untenable.  When you factor in the reliance on Soyuz that NASA wants to escape and the limited utility of a down-only CRV,  X-38 didn't make sense.  In hindsight, the original X-38 plan was probably better off in the scrap heap because its TPS wasn't a big improvement over the shuttle--still used tiles and possibly RCC on the nose and leading edges, with no metallic or hot-structure TPS.

Isn't a CRV more like a "fire escape" than an elevator?

I thought the mission of the X-38 was to dock with the ISS and be used =ONLY= for emergency delivery of ISS crew in the event rapid evacuation became necessary. In other words, the X-38 would not go up and down routinely.

Shouldn't a CRV be a redundant means of emergency escape? Any unnecessary systems are a total waste of money. And to dock a more capable craft as a backup redundant means of emergency egress seems wasteful as well.

Should we build additional OSP (superior and more capable to X-38) merely to leave one permanently docked to ISS "just in case" emergency evacuation becomes necessary?

What am I missing?

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