Texas Two Step flight report

Texas Two Step launched at 1921 PDT on Saturday, April 27, following a trouble-free integration except for a part we had to have driven out from LA. This flight was notable for a few reasons. First, Texas Two Step is basically two rockets in one, the most complex vehicle RPL has ever built. It was the first flight of an 8" motor case - Traveler will be the next. It was also the first time we used the launch tower.

Showing off the launch tower to the National Geographic film crew.
Sliding the rocket into the tower.

There were a few signs of trouble before launch, such as a malfunctioning first-stage igniter and the sustainer avionics reporting after a few minutes that they would be unable to light the sustainer. With about 10 minutes to sunset, we didn't have time to troubleshoot anything except the booster igniter, which finally worked. Texas Two Step looked incredible zooming through the tower:


Shortly after clearing the tower, the vehicle pitched slightly into the wind, adding to the angle that it already had from the tower. It continued straight for a while, then seemed to pitch down even more near the end of the burn. There was no sustainer ignition, either due to the software angle lockout or the electronics problems mentioned earlier. The booster drag-separated as planned at about 12,000' AGL. Avionics in the nosecone fired the CO2 cylinder to deploy the recovery harness. This was the first time we have successfully used the CO2 system in flight, a great plus for Traveler!


Because of the high horizontal velocity at apogee, the shock cord broke on both ends and the two pieces of the sustainer cartwheeled and fell in the lakebed 3.2 miles from the launch site. We received dozens of BigRedBee GPS pings during the flight, and were able to immediately postprocess them and view them in Google Earth, giving us a good idea of the landing location. Then, a few minutes later, we found that our SPOT satellite messenger device was still working, and we drove and walked in the darkness to the exact location it gave us. The sustainer and nosecone were about 20 meters apart, both with significant damage. The nosecone shell, a few fins, and the airframe were cracked. Fortunately, the propellant had not ignited on impact. We looked for the booster for a few minutes, but weren't able to find it. This weekend, when we return to the MTA to fire Tim's GOX-GH2 aerospike, we'll look for it some more. It should be easy to find in daylight on the lakebed. Because it is so unaerodynamic by itself, there's a good chance we'll be able to get video from the five cameras on board even if the recovery harness broke.

The recovery team.

Acceleration and barometric altitude data. Note the large spikes in acceleration at deployment and impact.
Though this launch didn't go according to plan, we're much more confident from the performance of the booster motor, the launch tower, and the avionics that Traveler will be a success when it flies this September at BALLS. An even more important milestone for that flight will occur May 20, when we fire the full Traveler motor in an aluminum case on a new thrust stand. If that works, it will be the largest motor RPL has ever successfully fired by a factor of three! We're already producing a new motor for the flight this fall.

We'll be posting lots of video and pictures of the flight and build process in the coming week, as well as more information about the static fire.