Helium Balloon

[owenander]

Would it be too crazy to build a hot air balloon that lifts rockets high into the atmosphere where they then launch?

 

[docm]

Over 50 years ago there was a device called "Rockoon" used in atmospheric research. More info here. Image below.<br /><br />The first time I actually saw this idea used was at least 20 years ago when a kid was using it with Estes rockets & igniter's, a barometric switch, a battery and a large home brewed helium balloon with an integrated "launch tunnel" through its middle and a transmitter for retrieval. Smart kid. Worked pretty good too.<br /><br />One of the X-Prize contenders, STABILO, was to be a balloon/rocket configuration but Rutan put the kibosh to everyone else's efforts. I understand they're still developing for the X-Prize Cup. <div class="Discussion_UserSignature"> </div>

 

[jpowell]

Rockoons are still going strong. JP Aerospace has flown quite a few:<br />http://www.jpaerospace.com/rockoons.html<br /><br />JP<br />www.jpaerospace.com<br /><br />

 

[j05h]

Along with those mentioned there was a hybrid-motor Rockoon flown by the Huntsville L5 Society in 1997. It had asphalt for fuel and flew through the balloon at launch. It had a pointy thing on the nose. They flew it from a barge off North Carolina. It peaked at 38 miles altitude, marking the record for hybrids (and amateur launches) until SpaceShipOne in 2004.<br /><br />http://www.nss.org/news/releases/release12.html<br /> <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[vogon13]

A reduced fuel load ICBM was launched from an airplane (can't remember if it was a Minuteman or MX, if forced to guess, I would say MX) ~20 - 25 years ago. Nothing inherently wrong about air launch other than the balloon or aircraft is going to be rather largish for some of the more useful applications . . . <br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[Boris_Badenov]

It's not crazy at all.<br /><br /><br /> Da Vinci Project Spacecraft Design.<br />& they are still in business.<br /> DreamSpace <br /> <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>

 

[jimfromnsf]

The air dropped Minuteman was a basing method vs performance enhancement

 

[why06]

seems to me lifting anything larger than a large custom model rocket would be uncoventional...Seems to me it would take a lhell of a ot of helium to launch a rocket caring anything of value signifigance... <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[j05h]

JP Aerospace has talked about building a "DarkSky Station" that would be a hotel/launch site in the upper atmosphere. They would haul rockets to it via airship, then launch from 140,000ft. Interesting concept.<br /><br />http://www.jpaerospace.com/dssoverview.html <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[docm]

<font color="yellow">Seems to me it would take a lhell of a ot of helium to launch a rocket caring anything of value significance...</font><br /><br />Dunno about that. Balloons have carried some pretty heavy payloads into the stratosphere and stayed there for days. One of note is the BLAST telescope (BLAST = Balloon-borne Large Aperture Submillimeter Telescope), which had a 2 meter mirror, weighed in at ~ 3 tons and used a single 140x120 meter balloon.<br /><br />An array of such beasts like JP proposes could carry a significant rockoon & payload. <div class="Discussion_UserSignature"> </div>

 

[spacenate]

Rockoon projects seem like one of those "no duh" sort of things. I don't understand why this relatively low-tech and low cost solution hasn't been explored further. The fact is that the physics flat out work.

 

[docm]

I agree 200%. <div class="Discussion_UserSignature"> </div>

 

[drwayne]

There is a savings of getting some of your altitude for "free", and launching in a reduced drag environment to be sure. (Including subtle benefits like changes you can make in vehicle structure to not have to deal with operating in the heavy air)<br /><br />Keep in mind though that if one is aiming for orbit with this beast, you still have to acquire the appropriate velocity, which is still a large part of your energy budget.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[jpowell]

I've put up a bunch more rockoon pictures on the JP Aerospace blog: www.jpaerospace.com/blog<br /><br />The biggest benefit we get from a rockoon launch is the reduction of structural mass of the launch vehicle. We typically can reduce the unfueled mass of the vehicle by at least 70%<br /><br />JP<br /><br />John Powell<br />JP Aerospace<br />www.jpaerospace.com

 

[keermalec]

JPA has is currently lifting balloons to 100'000 ft and plans to lift them to 140'000 ft. The air density at these altitudes is 0.018 and 0.0036 kg/m3 respectively, compared to 1.29 kg/m3 at sea level.<br /><br />From this link, the force required to move an airship at sea level density and pressure is about 14 N/m2 of airship section. Therefore at 100'000 feet that would be 0.2 N/m2 and 0.04 N/m2 at 140'000 feet.<br /><br />A 48 kg NEXT ion drive produces 2N thrust and should therefore be able to accelerate a small airship at 140'000 feet. JPA's idea I think is that if the airship shape is designed to produce lift, then it should be possible to lift it ever higher and faster until it reaches orbital altitude and orbital velocity. Sounds very promising.<br /><br />The problem is air drag is proportional to velocity squared. Therefore amaximum velocity is quickly attained at a given altitude. The question is: will the thrust applied be sufficient to lift the ship to a higher, less dense altitude before the velocity increase is stopped by air drag? <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>