New T-Space Updates

[nacnud]

I'm not an aerospace engineer but a few possible reasons might be.<br /><li>The rocket needs to go up, then along to reduce dynamic pressure.<li>The thrust vectoring is expenise/more complicated<li>The rocket would have to be strong enough to cope with the turning moment from the thrust vectoring.<li>The rocket passing behind the plane apparently give less chance of collition.<br /><br />The t/LAD system does the same as a pair of wings/thrust vectorying system for the cost and complication of a couple of bits of string and a length of of matierial.</li></li></li></li>

 

[tap_sa]

Your first and last are good reasons, no doubt. But having TVC is a requirement anyway, to guide and turn the rocket back to almost horisontal when it's cleared most of the atmosphere.<br /><br />Ah, silly me. It's the initial low (well below two) thrust to weight ratio that makes high AOA necessity, otherwise the rocket is unable to gain altitude at all. For a moment I was thinking too much air-to-air missiles which have so high T/W that despite gravity they go wherever their nose point.<br /><br />

 

[nacnud]

I think I did OK in guessing the reasons, here is what t/Space says are the advantages from it's paper on the t/LAD system.<br /><br /><font color="yellow">t/Space has base-lined an aft crossing trajectory that has several advantages as compared to the typical forward crossing air launch trajectory: <br /><ul type="square"><li>No requirement for wings or fins similar to those used on the X-15, Pegasus, or SpaceShipOne. heavy systems such as control surface actuators, auxiliary power units, and wing and fin thermal protection are eliminated. <br /><li>No possibility of the carrier aircraft being struck by debris from the rocket. The rocket passes more than 1500 feet behind the carrier aircraft if the aircraft executes a clearing turn after the drop (clearing turn not shown in figure 1). <br /><li>Reduction in peak 1st stage engine Thrust Vectoring Control (TVC) from about 6 degrees for the forward crossing trajectory to less than 1.5 degrees for the aft crossing trajectory. <br /><li>Peak dynamic pressure (Q) cut by more than 65% from 1400 pounds per square foot (psf) - such as experienced by Orbital’s Pegasus air launched rocket - to less than 500 psf. Trajectories with peak Q less than 350 psf are possible from a high flying custom aircraft. <br /><li>Elimination of flying at high Angle of Attack (alpha) throughout the high dynamic pressure segment of the trajectory. For the aft crossing trajectory all maneuvering occurs under Mach 0.65. Forward crossing trajectories (for rockets without wings on them) require flight at large values of alpha resulting in very large products of dynamic pressure (Q) and alpha. Large Q•alpha increases the weight of a rocket's structure, which in turn can reduce the payload to orbit. Aft crossing trajectories involve flight with normal values of alpha (less than 1 degree) when supersonic. <br /><li>A payload increase to orbit as compared t</li></li></li></li></li></li></ul></font>

 

[tap_sa]

Yep, well done. At least I assumed the higher drop speed right.<br /><br /><font color="yellow">"Another scaling factor was the low launch speed of the Proteus carrier aircraft. True air speed at drop was less than 200 feet per second (fps), compared to about 600 fps for a modified 747 carrier aircraft or for a proposed Scaled Composites’ custom designed aircraft."</font><br /><br />Btw the paper had 747 in the pictures, a tiny clue that they are pursuing that option more seriously? Even Scaled might have to get bigger autoclaves to really build 747 sized VLA from composites.<br /><br />And exact dimensions of the 23% scaled model were given so the real booster would be 27.6m long, 4.1m diameter. <br /><br />edit: Oh, and I'm a planet now. Whee!

 

[nacnud]

Good point. Anyone know where to find a 747 lying around, not doing much, somewhere near Mojave? <img src="/images/icons/cool.gif" />

 

[tap_sa]

Is that the Richard's spare he considered sinking into caribbean as a tourist attraction? But will he donate one for the good cause now that DOD maybe considers him a possible british terrorist, denying access to SS2?!

 

[nacnud]

It's NASAs 747 Shuttle Carrier Aircraft <img src="/images/icons/smile.gif" />, the red thing above it is used to put the Shuttle on the back of the SCA.

 

[dreada5]

<blockquote><font class="small">In reply to:</font><hr /><p>I for one do not believe that we have seen the last of T/Space with announcement that either LM or Boeing will be building the CEV. <br />One way or another, I think the CXV will be built. <p><hr /></p></p></blockquote><br /><br />Yeah, I'm a little concerned about that too, as it looks like NASA will be selecting the more experienced but not necessarily the best contractors (Boeing/LM) for the job. <br /><br />I think the experienced Boeing/LM are definitely needed to provide the actual Lunar hardware. But I'm not too keen on the LEO space transportation systems ie EELVs for cargo. Even the shuttle-derived concept seems more attractive!!<br /><br />In any case I don't think NASA should be using those big contractors with the EELVs to get to people LEO. That should be a job for people like t/space and their idea is so cool... airborne-launches is the way to go, me thinks!!<br /><br />I wonder what t/space will do now, I know they are still funded until September.

 

[gladiator1332]

I would like to see them at least develop their booster and use it to launch a small satalite, or maybe a dummy CXV just to show they can use it to put something into orbit. This will take some time, so I don't know of any quick solutions to get NASA to believe that t/space would be able to build the CXV.<br />It all comes down to whether Griffin will let go of his "no parallel" concept policy.

 

[gladiator1332]

That is very reassuring. <br /><br />The great thing about t/space is that we don't know what is going on behind the scenes. Not many outside of t/space knew that these drop tests were going on until they were officially announced. <br />They've been working on the CXV since December, so they kept a lot of stuff secret for awhile. They could be cutting metal right now and we wouldn't evne know it. So who knows what else they have in store for us over the next two months. And while it is a bad thing for the private space effort, it may be for the better that the whole Space Ship Two thing did not work out. I would have loved to see Virgin Galactic take off, and I hope we haven't seen the last of it, but now Rutan has more time to work on the CXV. I don't see how he was going to build a fleet of two different spacecraf at the same time. Not even Boeing or Lockheed have tried to do that. <br />Griffin is just as unpredictable. He has said some things that would lead you to believe t/space has a shot, and he has also said things that make you believe t/space is dead in the water with NASA. What it is going to take is either Lockheed or Boeing incorporating t/space into their plans in some way. Lockheed has shown some interest already and even went as far as praising the t/space plan. <br />So I really think they still have a shot with NASA. We'll have to see what Boeing and Lockheed release, and see what Griffin says as well.

 

[scottb50]

When I was at Mojave for the first Spaceship 1 flight there appeared to be a few laying about there, as well as a lot of other airplanes. <div class="Discussion_UserSignature"> </div>

 

[gofer]

Meanwhile, somewhere in the Pacific Ocean... The t/Space folks keep chugging along... <br /><br />Some parachuting splash tests.<br /><br />http://transformspace.com/index.cfm?fuseaction=news.view&newsid=82CB9620-04E9-581D-BD4C7D24F6019AC8<br /><br />some neat photos/videos via a link at the bottom.<br /><br />next step a ballistic trajectory launch test? doesn't necessarily have to be the original airlaunch scheme I presume. but who'd give them an inexpensive ride? hmm...

 

[gunsandrockets]

Finally! Some hard numbers on the t/Space CXV capsule were released as part of the story of the capsule parachute tests.<br /><br />The 4 man CXV capsule is 14.75 feet long and 14 feet wide and weighs 8,100 pounds. That is incredibly light for a 4 man spacecraft, especially when you consider the capsule contains everything that would ordinarily get stuffed into a separate service module.

 

[nacnud]

It also hits 4.5g during the latter stages of launch, but for $20M for 4 to LEO and in an emergancy 8 down you have to wonder how NASA, Bigleow and t/Space themselves won't somehow make this a reality.

 

[nacnud]

The engines are from LLCs Airlaunch program, funded through DARPAs falcon program (not to be confused with the spaceX falcon I). The TPS is I think from a NASA program. <br /><br />The VLA could be a sticking point. That is if it isn't the same as WK2, or maybe WK3.

 

[nacnud]

Me neither <img src="/images/icons/laugh.gif" />

 

[wvbraun]

Good news!<br /><br /><i>NASA plans a competition this fall to select a new vehicle to carry crew to the Space Station. t/Space will offer its four-person CXV.</i><br /><br />I think they have a very good chance of winning this.

 

[thermionic]

<br />Can someone give me a quick explanation of the water cooling mechanism please? thnx...

 

[nacnud]

From here<br /><br /><font color="yellow"><big><center>Rugged Thermal Protection System</center></big><br /><br />The t/Space CXV has the same shape as the Corona film-return capsules used in the last century by the intelligence community. The blunt shape reduces the thermal extremes caused by the sharp edges of winged vehicles.<br /><br />The CXV exterior will be covered with two layers of low-cost ablative SIRCA tile (Silicone Impregnated Refractory Ceramic Ablator). Developed by the NASA Ames Research Center, SIRCA consists of a fibrous silica substrate impregnated with silicone. Each SIRCA layer will range from 0.75 inch thick on the forward dome to 0.375 inch thick on the cone. The seams of each layer will be offset to prevent burn through.<br /><br />The outer layer will be sufficiently robust to protect the capsule through several reentries. Periodically, the outer layer can be replaced with fresh tiles. Mars Pathfinder successfully landed on Mars on July 4, 1997, using a SIRCA-covered back interface plate heat shield. The recent Mars Exploration Rovers also employed SIRCA on their backshell interface plates. In addition, SIRCA was selected for use on the X-34, and was certified for 25 flights via arc-jet testing.<br /><br /><font color="white">No mention of water cooling…<br /></font></font>

 

[j05h]

what I find interesting about these drop tests is that they have almost replicated the x-38 program's test flights with $6 million instead of ~$500 million that x-38 consumed. <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[wvbraun]

Are Boeing and Lockmart even interested in this? SpaceX seems to be preoccupied with the Falcon I/V...

 

[radarredux]

> <i><font color="yellow">Are Boeing and Lockmart even interested in this? SpaceX seems to be preoccupied with the Falcon I/V...</font>/i><br /><br />I think SpaceX is just focused on getting their first rocket off the ground and then making enough money and attracting enough capital to expand his business. <img src="/images/icons/wink.gif" /></i>