Dynasoar

[pmn1]

http://www.astronautix.com/craft/dynasoar.htm<br /><br />The X-20 was pushed as an alternate to the Gemini as a space station ferry vehicle in the twilight days of the program. If only it had been accepted, the US would have had a space station and winged ferry vehicle flying before the end of the 1960's.<br /><br /><br />How accurate would you regard this statement from the Astronautix site and what implications would funding for the X20 have on future programmes? <div class="Discussion_UserSignature"> </div>

 

[docm]

X-20 data eventually led to the HL-20 (the basis for SpaceDev's Dream Chaser) and the HL-42 (an upscaled design), both of which IMHO should have been continued. If they had we wouldn't have a problem with dropping the shuttle while maintaining a continuous manned capability. <div class="Discussion_UserSignature"> </div>

 

[spacy600]

I can not find it now, but<br />The CEO of Spacedev said something about working on<br />a "extended version of the hl-20 / Dream chaser"<br /><br />Have you heard that and can this be what he was referring to?<br /><br />Thanks

 

[js117]

It's on Spacedev website.

 

[docm]

Link? <div class="Discussion_UserSignature"> </div>

 

[qso1]

Theres no real reason I can see that this could not have happened had it been pursued. In a way its too bad we didn't get an operational Dynasoar system by the late 60s. As for funding, hard to say because the Dynasoar program itself may well have gone operational in 1968 only to be drastically cut by 1973 assuming that all other historical events played out the way they did.<br /><br />The problem now is that we had a chance to develop another Dynasoar like system in the early stages of the Constellation program but because capsules are easiest and cheapest...we went capsule. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[docm]

Don't forget safest when dealing with lunar return velocities. Spaceplanes are fine for LEO, but present problems when reentering at higher velocities.<br /><br />Besides that: who needs wings flying to the moon or mars? Their extra weight also cuts payload/crew capacity. <div class="Discussion_UserSignature"> </div>

 

[qso1]

The scenarios I'm referring to do not require the winged part of the system to leave earth orbit. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[spacy600]

This is good, I have not seen this before..<br />http://tinyurl.com/2k8cte<br />page 15, but has other neat info..<br /><br />I have to look at this in more detail.<br /><br />Latter

 

[docm]

Obviously put together before they made the decision to split off suborbital to a less expensive/simpler spacecraft. Still; the info on the two versions is interesting, especially the main N2O tank being around the docking/EVA tunnel. <div class="Discussion_UserSignature"> </div>

 

[spacy600]

That issue has been resolved. See the last couple of<br />conference calls, near the end of the calls, at least one<br />investor call in with that question.<br /><br />Dream Chaser standard, extended versions are not the same dimensions as hl-42. I wonder why, any thoughts why they did not go with hl42? (for the extended version?

 

[docm]

HL-42 was a 42% scale up of the HL-20 with a launch mass of 28,700+ kg (counting adapters & escape system), so probably its mass. Only heavy's need apply, and they've been in short supply. <div class="Discussion_UserSignature"> </div>

 

[spacy600]

ok, thanks!

 

[vulture2]

I am not sure hybrid propulsion really makes sense. The original theory was that it was safer, but that may be an artifact of the fact that there is less actual experience with the hybrid. Reuse of hybrids may well be more expensive; let's remember that the X-15 with fairly high performance all-liquid propulsion made 199 flights. Personally I think that hybrid propulsion will ultimately not prove to have any lasting advantage.<br /><br />It's also interesting that almost exactly the same structural configuration was proposed by the Langley team for the Crew Emergency Return Vehicle. For that mission the high L/D and low entry G forces would have been a real advantage, since the medical emergency return scenario required the vehicle to deorbit quickly (aided by large crossrange) minimize stress on the patient, and land near a hospital, which was aided by the runway landing capability. Of course, CERV was cancelled.<br /><br />The later Orbital Space Plane program also started with a similar concept but was tending toward a capsule design before its cancellation because of higher volumetric efficiency and the fact that if entry time isn't critical one can simply do an orbit change (plane or altitude) that will bring one over the desired landing site within a few orbits, so crossrange is not critical either. <br /><br />Still, the CEV hasn't proven it can land on land without damage or be economically reused if it lands in the ocean. The ability to land on a runway is a real advantage for the Shuttle in enhancing reusability, and I would not discount it. <br />

 

[tomnackid]

The X-20 was pushed as an alternate to the Gemini as a space station ferry vehicle in the twilight days of the program. If only it had been accepted, the US would have had a space station and winged ferry vehicle flying before the end of the 1960's. <br />----------------------------------------------------------------------------<br /><br />What makes you assert that? The x-20 was a classic case of a solution desperately looking for a problem. Its original purpose was to be the piloted "antipodal bomber" that Sanger first proposed back in the 40's. It was designed to use atmospheric skips to travel around the world then back to a landing zone. It initially wasn't even designed to be fully orbital. As ICBM's and conventional jet bomber technology advanced (specifically increasing the range of early jet engines) the need for a spaceplane bomber became harder to justify. The Air Force then developed the x-20 into a fully orbital vehicle and pushed it for use as a ferry for manned spy satellites--or alternatively as an orbital spy plane. Advances in electronics and telemetry made the concept of a manned orbital spy platform obsolete. Even thought the x-20 was the first manned space vehicle to begin development in the US there were still many unsolved problems with power usage, control and heat dissipation that were not solved before the projects cancellation.<br /><br />All in all the x-20 was designed for a purpose that no longer existed long before the program was finally canceled. maybe it could have been turned into a cramped, expensive, semi reusable ferry but that would have made about as much sense as trying to turn a f-22 into a cargo plane. Pretty wings and landing gear would not have gotten us to the moon any sooner.