Archive for October, 2011
Here’s a few clips while we sort through the video.
Before driving Tandem at the edge of space the propellers need to be balanced. After balancing them with little pieces of tape I pull off and weight the tape. Then I weight out epoxy and use a syringe to eject it into the hollow tip of the blade. The blades are hollow carbon/Kevlar blades we make ourselves. One prop set took 2.3 grams of epoxy and the other was way off and took 5.4 grams.
Tandem will be JP Aerospace’s 126th mission.
It was a late night calibrating the new helium flow meter. After all the fun we had filling, deflating, filling, deflating (wash, rinse, repeat) an eight foot balloon in the electronic room we decided to check the calibration of the existing meter. The good news is both meters match exactly. This is really going to speedup the Tandem fill time.
Tandem has been in the shop for three years. Yesterday she got outside a bit to get some fresh air. This was the last big step. We disassembled Tandem as we would for shipping,took her out to the front parking lot, reassembled her and ran full system tested. This was both an engineering and a training exercise. It was a very long and hot day for the team, but they really worked out all the little details and got Tandem ready for flight.
There is a new vehicle that we will be flying with Tandem.
The new vehicle will be both a chase vehicle for Tandem and chance to run really high.
It’s called the Mesospheric Explorer 2 (ME Too!).
The Mesospheric Explorer One was flown about 10 years ago. It was intended to break our altitude record of 130,000 feet and be the start of a series that would reach the Mesosphere (160,000 feet). The ME One vanished at 30,000 feet never to be heard from again.
ME Too will use two of the big Tandem balloons (the Tandem backups). However instead of 62 pounds like the Tandem it only weights 11 pounds. It will climb fast and high.
It’s carrying four HD video cameras covering 360 degrees. Our goal is to launch it 30 minutes after Tandems launched. It will then get great in flight images of Tandem as it passed her at 50,000 feet. It will then keep heading up to over 120,000 feet.
Here she is to scale at peak altitude:
The team pushed hard on Tandem Saturday. There were lots of small changes and one big one.
The big change was the recovery system. After it’s flight Tandem releases it’s balloons and deploys a parachute. We had a large parachute cannon near the nose that used a cold gas and piston system to throw out the chute. Last week we conducted six ejection tests. It worked but pretty anemic. I was really looking for the parachute to be thrown five to six feet away from the structure. We been making steady improvements on it, however it really needs a bit of a redesign and there just isn’t time. We decided to go back to old, reliable basket deployment that we use on Away missions. Off came the cannon and on went five baskets and small chute arrayed down the length of Tandem. The good part is that we saved 2.5 pounds, unfortunately we ate up that weight in bigger propulsion batteries. The change meant that we had to do a complete rebalancing of Tandem.
Other things accomplished:
All camera housings completed and two mounted.
Motor RPM and temperature sensors mounted.
New motor controller housing insulation sleeve made.
Main system controller wiring harness modified.
Corner bumpers made and installed.