Burt Rutan to build orbital "SpaceShipThree"

[tomnackid]

I call it carefree if the spacecraft brings you down alive despite severe technical malfunctions. AFAIK Soyuz chute deployment is automatic so you´ll be saved even if you´re temporarily unconscious after rougher than usual ride. SS1 is in wrong category and hardly carefree because shuttlecock wingtips don't fly you all the way down to airstrip, piloting is required. CXV is the closest to Soyuz. It too requires computer control to provide lesser g reentry and probably does the ballistic version if that fails (this assuming it will have axisymmetric heatshield).<br />---------------------------------------------------------------------------------------<br /><br />I was talking about reentry, not landing. Two very different things. Soyuze, Apollo, Gemini, Mercury are all inherently unstable. Without some reaction control during reentry they will tumble. (Unstable with respect to the entire flight profile. At some speeds and altitudes they are stable.) Note, the Soyuz in question didn't lose its computer completely, the program just defaulted to the ballistic mode. The RCS did not attempt to angle the capsule against the airflow to generate lift, it just kept it straight on to the flow.<br /><br />The Corona "shuttle ****" shape and the Vostock sphere with an offset center of gravity are examples of inherently stable reentry vehicles. So is the SS1 with its "feathered" wing.<br /><br />There is nothing inherently better or worse about "care free" reentry vehicles. They may be cost effective solutions in some situations but not for others. I doubt that a Vostock or Corona derived vehicle could ever reenter from anything higher than LEO without encountering g-forces above human tolerance. Conversely the shuttle may be difficult to fly but it will be a long time before a capsule with parachutes can bring back 23,000 pounds from LEO and land on a runway!<br /><br />

 

[mrmorris]

<font color="yellow">"Soyuze, Apollo, Gemini, Mercury are all inherently unstable. Without some reaction control during reentry they will tumble. "</font><br /><br />You are incorrect. Do some more research.

 

[franson_space]

Branson said he wants to take his family up on SS2, but his Mum said "Not a chance in hell" <img src="/images/icons/smile.gif" /> Wish I was a relative!!

 

[tomnackid]

I was mistaken about Mercury, it forgot that it was designed for a purely ballistic reentry and most of its weight was in the base making it aerodynamically stable--which was very lucky for Gordon Cooper since he had to reenter with NO electrical power in his capsule! (Amazingly he still landed within the calculated recovery zone!)<br /><br />However Gemini and Apollo were cones with offset centers of gravity and a heat shield on the big end. They both had a tendency to flip over and reenter apex first. In fact ICBM reentry capsules are cones with ablative material at the tip and are designed to reenter point first since this is the most stable configuration.<br /><br />From the Encyclopedia Astronautica:<br /><br />"North American reported several problems involving the CM's aerodynamic characteristics; their analysis of CM dynamics verified that the spacecraft could - and on one occasion did - descend in an apex-forward attitude. The CM's landing speed then exceeded the capacity of the drogue parachutes to reorient the vehicle; also, in this attitude, the apex cover could not be jettisoned under all conditions. During low-altitude aborts, North American went on, the drogue parachutes produced unfavorable conditions for main parachute deployment."<br /><br />I don't want to get into an argument over what is the "best" spacecraft. The Soyuz is a cheap and reliable, but very limited. The shuttle has awesome payload and passenger capabilities but is expensive and relatively fragile. Piper Cubs and 747s are both great aircraft, but I would not land a 747 at Danbury Municipal airport, nor would I try to fly 300 people across the Atlantic in a Piper Cub.<br /><br />Of course by now one would hope that the US--or anyone for that matter--could afford to build a spacecraft that is robust AND has awesome capabilities! We seem to be screwing ourselves by trying to do everything on the cheap.

 

[mrmorris]

<font color="yellow">"They both had a tendency to flip over and reenter apex first."</font><br /><br />I am unaware of any such problem with the Gemini capsule. There was an unfavorable apex-forward condition that was <b>possible</b> for the Apollo Command Module. A 'possibility' is not the same thing as a 'tendency'. As the link you mentioned indicates -- it could only happen on low-altitude aborts -- <b>not</b> on re-entry... which is the point of the thread. Another link on the subject is here where NASA recently did a computer-based optimization of the CM shape:<br /><br /><i>"The baseline Apollo CM (employed on all flights) is stable and trimmed in a dangerous apex forward position which poses a safety risk <b>if the CM separates from the launch tower during abort</b>. Optimization was employed on the Apollo CM to remedy this undesirable characteristic. "</i><br /><br /><font color="yellow">"I don't want to get into an argument over what is the "best" spacecraft. "</font><br /><br />And I'm not suggesting any. I'm just pointing out that you are making incorrect statements about the re-entry stability of several spacecraft.

 

[shuttle_rtf]

I understand the quotes was "I'm not going up in any of his play things." She'll never know how ironically true that statement was when she said play thing.

 

[tomnackid]

From a NASA website:<br /><br />"The Soviets, under the leadership of Sergei Pavlovich Korolev, chief designer of spacecraft, reviewed the different possibilities and chose the sphere for their reentry configuration. According to Korolev, among non-lifting shapes the spherical reentry body alone possessed an inherent dynamic stability as it plunged back into the earth's atmosphere. He rejected the conical craft, because its tendency to pitch and yaw would have required an elaborate attitude control system, plus greater reliance upon man as pilot rather than man as passenger."<br /><br />What more do you want? Truncated cones are NOT inherently stable. Not that they don't work well.

 

[tap_sa]

<font color="yellow">" There was an unfavorable apex-forward condition that was possible for the Apollo Command Module. "</font><br /><br />Mercury had the same thing, both base-first and apex-first flight attitudes were stable (perhaps all clearly conical shapes behave like this?). The engineers added a special reentry spoiler (at lower right corner in the pic) to make sure the spacecraft would automatically flip if reentry would initiate apex-first. <br /><br />Dunno about Gemini but IIRC the astronauts considered it the Ferrari of capsules, being the most agile to maneuver.

 

[tomnackid]

Gemini, Apollo, and Soyuz DID have an attitude control systems. I'm not sure what you would consider elaborate--Korolov in the 50's was thinking in terms of attitude control sytem under pilot control an rejected it as being impractical. When Gemini, Apollo and Soyuz were eventually built electronics were able to take over attitude control on reentry and compensate for the capsules tendecy to pitch and yaw.<br /><br />The early Gemini flights landed far from their intended splashdown points. NASA finally realized that there reentry attitude control systems were programmed with the weight of an INTACT heat sheild. As the shield ablated it lost mass and threw off the attitude control system. After studying how the shield ablated througout reentry NASA was able to reprogram the attitude control system and acheived more accurate landings.

 

[tap_sa]

<font color="yellow">"Early missions used the same rolling entry as Mercury."</font><br /><br />I wonder if any of them sang during reentry;<br /><br /><i>Roll, roll, roll your pod,<br />Gently down the stream.<br />Merrily, merrily, merrily, merrily,<br />Life is but a dream.</i>

 

[ronatu]

Before Rutan it was Boeing, Rockwell and others (1979-1993):

 

[kdavis007]

Than what is your problem with Virgin Galatic then???

 

[ronatu]

And finally russian project MAKC (1988):

 

[ronatu]

In comparison, how is Rutan's project looks like?

 

[tomnackid]

I have struggled to find a nice way to say this, but there just isn't one. So,.... <br />------------------------------------------------------------------------------<br />Incorrect, but thank you for playing. I don't really want to keep harping on this since its really off topic, but just so you know I'm not making this stuff up...<br /><br />"The early flights were having a problem in that the Gemini missed the target by a considerable distance," Eaves said. "It was important to rescue the capsule as rapidly as possible as there were astronauts on board. Mr. B.J. Griffith, a Tunnel F engineer, observed that the recovered Gemini capsule had an ablated reentry heat shield, and the NASA provided reentry flight profile had not taken the ablated shape into account."<br /><br />Testing was conducted in Tunnels F and B with an ablated shape similar to a recovered capsule and provided evidence that explained why Gemini was missing its splashdown point, Eaves said.<br /><br />"Many test facilities provided the necessary test capabilities to gather test data for getting to space," Eaves explained, "but there were few that provided information for returning back to earth."<br /><br />and...<br /><br />"Discussing the landing point error of Gemini 3, Charles W. Mathews told the Gemini Management Panel that the spacecraft had developed a smaller angle of attack than planned and that the lift capability had been less than wind tunnel tests had indicated."<br /><br />-- Minutes of Project Gemini Management Panel Meeting held at MSC, May 5, 1965.<br /><br />I admit I was wrong in saying that it was the change in MASS of the heat shield, it was actually the change in SHAPE.<br /><br />Look all I am saying is that a lifting shape like Gemini, Soyuz, Apollo is not "care-free" in the way that a Vostock or Corona capsule is "care-free". Shapes with greater than zero LD have to be oriented during reentry in order to generate lift.

 

[wvbraun]

"In comparison, how is Rutan's project looks like?"<br /><br />Nobody knows. There is no reliable information on SS3 at this point.

 

[mrmorris]

Double-post deleted.

 

[mrmorris]

<font color="yellow">"Look all I am saying is that a lifting shape like Gemini, Soyuz, Apollo is not "care-free" in the way that a Vostock or Corona capsule is "care-free". Shapes with greater than zero LD have to be oriented during reentry in order to generate lift. "</font><br /><br />And what you're saying is still either <i>wrong</i>, or an incredibly narrow definition of care-free. The only reason for orienting capsules that generate lift is to steer them towards the landing target. If the RCS were to fail entirely and early on a semi-ballistic capsule, then what would happen is that the lift would remain essentially on one direction for the entire flight. This would skew the flight profile -- changing the landing target from what the purely ballistic impact point would be, but the capsule would not be in danger from the re-entry itself. Mind you the landing point might be inconvenient/dangerous -- but you've already stated this is not about the landing but the entry.<br /><br />So -- on a purely ballistic capsule -- since the trajectory is <b>always</b> 100% ballistic, the flight path is set in stone. On a semi-ballistic, the flight path might vary.<br /><br />I can't see as how this makes a ballistic capsule 'care-free' and the semi-ballistic '<b>not</b> care-free'. This is especially true when your original statements also included SS1 in the 'care-free' category and its feathering certainly doesn't provide a purely ballistic flight path. You also included the CXV into that category and it will almost assuredly be using an offset cg for steering as well.<br /><br />So what exactly is your definition of care-free such that the Apollo, Gemini and Soyuz capsules do not fit into it, but Vostok, Corona, SS1 and the CXV do?

 

[tomnackid]

Ok, I am officially tired of the pissing contest over the definition of "care-free" reentry. If it makes you happy mrmorris I give up. You win. OK? Can we go back to discussing SS3?

 

[grooble]

I think SS3 will use the same massive air vehicle as CXV. And this massive air vehicle will probably be an enlarged version of the White Knight 2.<br /><br />I am hoping SS3 is not a rocket but a spaceplane as spaceplanes are the way to go for the civilian / tourist space industry. <br /><br />

 

[nacnud]

That depends on the cost of the spaceplane. The CXV is supposed to cost $20M per launch, say $10M per tourist. Thats got to be a really cheap spaceplane. How much extra would you pay for a drop of 1.5 g?

 

[chonner]

Ok heres what i think could be done, just speculating, haven't though about the practicality of it yet so feel free to critisize.<br />I think SS3 (assuming it is not the CXV) will use an englarged SS1 (both carried in tadam under WK3) as its hybrid booster so get it up to say 70 mile, then it will seperate and SS3 will ignite its engins and carry on up to orbit and maby dock with a bigelow station, meanwhile the englarged SS1 booster will perform its shuttlecock re-entry and glide down to an airport. So its effectively a 3 stage design consisting of 3 different planes/spaceplanes. How SS3 would perform rentry, i don't have clue, so yeah you can shout at me for that, but i would hope it would just be able to glide down to a runway once its slowed down enough. Havn't got a clue about a TPS.<br /><br />You could even take passengers up on suborbital flights in the Stage 2 booster and could get more cash that way? Just speculating.<br /><br />So yeah thats probably completely impracticle to implement but thats what i would like to see happen.<br /><br />Chonner

 

[nyarlathotep]

<blockquote><font class="small">In reply to:</font><hr /><p>That depends on the cost of the spaceplane. The CXV is supposed to cost $20M per launch, say $10M per tourist. Thats got to be a really cheap spaceplane. How much extra would you pay for a drop of 1.5 g?<p><hr /></p></p></blockquote><br /><br />Considering that to launch the mass of a spaceplane you're going to need a stick atleast Delta IV Heavy sized, quite a lot extra i'd imagine. <br /><br />That is unless you've designed either some sort of antigravity device or nuclear ramjet into your vehicle, in which case all bets are off.

 

[mrmorris]

<font color="yellow">" If it makes you happy mrmorris I give up."</font><br /><br />It has nothing to do with making me happy, or one of the two of us 'winning' the argument. I don't like to let incorrect 'statements of fact' to go unchallenged because people who read the information on these forums tend to assume that the data here is correct. It is all the worse because you obviously are reasonably knowledgable about the subject. If someone makes a post that contains ten 'statements of fact', of which nine are incorrect, then anyone who reads the post is likely to be able to determine that the data is not trustworthy and can be discounted. However, if only <b>one</b> of the ten statements is incorrect, a reader is liable to assume that all of them are correct -- even to the point of changing any prior viewpoint they might have had on number 10.<br /><br />Therefore, the more knowledgable you are, and the more you present yourself as a trusted source of information, the more important it is that you get all of your facts correct <b>and</b> that you acknowledge any errors you make. There is an example in the Hubble de-orbit thread I started. My initial post is based on a piece of information that shuttle_guy presented in a post several months back -- namely that SM-4 did not have the performance to carry a de-orbit module to Hubble. I didn't even question it -- S_G is the authority. I didn't even question how they put Hubble into that orbit. In my mind, I invented a scenario -- namely that they must have put it in a lower one and had an attached booster put it to the higher orbit. You might make note of the fact that S_G <b>always</b> acknowledges any erroneous statements he makes when they're pointed out. He does not simply ignore them, or argue with them, or 'give up' to keep the thread on-topic.<br /><br />I've done huge amounts of research on capsules -- primarily Gemini and Apollo and put much of what I learned into my Gemini thread on B&T.

 

[ronatu]

Paul Allen's space tourism company <br />-----------------------------------------------------------------------<br />Just read in a magazine that now that Paul Allen & Burt Rutan have built the Space Ship One with which they became the 1st privately funded aircraft to break the sound barrier & the first private enterprise to fly a man above 62 miles (which seems to be where a pilot is refered to as an Astronaut) and they now want to build a larger version of the SS1, The SS2 probably which would be a 10 person or larger craft that would fly even higher than the SS1 allowing passengers to experience weightlessness for a period of time.<br /><br />PA has stated that his goal is to build a hotel in orbit & he has the $ & contacts to pull this off if anyone does. This hotel would be at roughly the altitude of the ISS in Low Earth Orbit or LEO. A 2rd ship the SS3 which would be between the SS1 & SS2 size wise would take people up to this hotel. Reentry from LEO is considerably more difficult than from 62 miles or even 100 miles so the SS3 would be a lot more expensive, tougher, & more high tech than the SS1 or SS2.<br /><br />By the way the Co that builds the rocket engines for these craft is Space Development Corp which trades OTC around $1.50 now, Good buy before SPDV goes through the atmosphere too <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /><br />