Archive for November, 2008
Last weekend we again had one of the Ascender 100 arms inflated in the parking lot. We were going to test both the original rib that had been extended and a new rib. During the initial inflation there was a POP! The inner cell of the original rib burst. We continued with the tests of the new rib. This rib design was significantly better that the first one. The test also pointed out a number of flaws in the design we well as a couple of operational problems. No problem through, that is what the test was for. The next generation of rib is being designed. I suspect we’ll need eight to nine generation to really hone it in. We’re also working on new filling gear with new low pressure gauges. We need also to monitor the ambient pressure inside the main envelope in addition to pressure inside the rib. It’s way too easy to over pressure the outer envelope and creating forces to great for the rib to overcome.
The team really put in a hard days work on this one.
Here’s some pics from the Wednesday night build session before the test:
This is from the size check of the test rib two weeks ago. We just finished the second test rib. If it doesn’t rain we’ll be checking it’s fit this coming weekend.
A group of engineering students from California State University Sacramento lead by our own K’John are managing the Away 28 upgrade project. They’re in the process of an end to end structural analysis of the vehicle. Yesterday they prepared a segment of carbon tubing for load testing. The challenge is putting on mounting rings that are stronger than the tube so it can be mounted in the testing machine.
We been changing to new frequencies on our telemetry systems. One of the results is that we no longer need the big “double boomer” phased antennas. We still use one of the single long antennas. The single antenna stand doesn’t need to be as beefy a stand as the double does. The old stand could hold two antennas in high winds without a problem but it came with a price. It takes two people thirty minutes to assemble each one of them in the field. They’re so complicated that we always have an antenna assemble training session before each mission.
Saturday the team took one of the dish antenna stands and modified it for single long antenna use. It came out fantastic. The new stand only takes five minutes to setup. Not only will the new stand save us gobs of time in the field, but it’s much easier to pack and has a much smaller part count.
Work continues on the refurbishing the rocket launch box. Saturday the two layers of foil were glued to the inside surfaces. The foil protects the foam from catching fire from the rocket’s blast. We’re be using this box for a systems test flight. The rocket will be there but not launched. However the foil changes the radio environment of the box. It needs to be there so the test will be accurate.
Foiling the box interior.
Here are some older pics of launch boxes:
We really need to get busy.
Last night we made a new inner cell for the rib. The inner cell is a 14 meter long 50cm in diameter tube with a high pressure and low pressure nozzles attached. It’s cut and assembled from 0.7 mil sheet poly. We also added snaps to the rib access panels. The velcro was starting to pull away a bit on the last full pressure test. The snaps will help keep the panels in place.
Here’s the partially inflated Ascender rib test article. In addition to making it bigger we added more access panels. The access panels make it easer to keep the inner cell aligned correctly when it’s being installed. It really does form a nice ellipse when fully inflated. Ascender 100 will use nine of these. Eight this size and one larger bow rib.
Instead of starting from scratch we decided to modify the Ascender rib from last week. We found the error and have made eight extensions to bring it to the correct size. A lot of Saturday was spent pulling seams, an eighteen foot ellipse all double seams at the perimeter and triple seamed at the joints has a LOT of seams. With that accomplished we’re started sewing back together again. Sometimes….
The control servo was mounted on the reel down system and the next round of testing should start this week.
On the rocket balloon launch box the bridal mount was installed. This is the structural backbone that gets attached to the balloon.
Tucked, unmarked, in a back corner of Smithsonian Udvar-Hazy Center hangs one of the most amazing planetary probes ever flown. I came across it on while doing the book signing there for “Floating to Space”
It is the Vega balloon that flew in the atmosphere of Venus, well it’s the backup vehicle. The real one that flew in 1985 is still on Venus. This single mission put a lander on the surface of Venus, sent a balloon flying in the atmosphere and sent the “mothership” to intercept Halley’s Comet. All three elements of the mission were a success. Incredible.