MTA Blockhouse Repair Nov 6-7, 2021

by Dimitri Timohovich, RRS.ORG

Saturday started with bringing the loader over from FAR.

Loader and blockhouse with the old roof
Blockhouse with old roof timbers removed

Bill and Jon arrived as the demo was finishing up and we quickly jumped into removing the nuts that held the old 2x6s on top of the cinder block walls. 

It was a pleasant surprise to see that all the cells were filled with concrete.  Bill and Jon cleaned the bolts while I cut the new 2x6s and drilled new holes for the bolts to go through.

Bolts in the blockhouse walls

We attached the new 2x6s and added an additional one to the front of the blockhouse to give the roof a slope to shed rain water.  By the time this was done, it was lunch time.

Bill Inman looking at his favorite rocket power source
Another shot of the 2×6 beams installed on the blockhouse

After lunch the 1 1/8” Tongue and Groove plywood was installed.  I brought the loader over from FAR and Jon was able to send up pieces in the bucket.  The wind started to pick up and we had to fight a little to get the plywood in.  After lining it up and tapping the sheets together I screwed them down to the 2x6s.

Plywood installed on the blockhouse roof

We then used the loader to lift up a couple of the timbers into place and were able to do a test fit.  By now it was getting late and we decided to call it a day.

The first railroad timbers in place for a test fit
Discussions with our neighbors near the end of daylight
Getting the alignment right for the timbers & adding screws
Blockhouse state at the end of the first day of work

Sunday morning was dedicated to getting all the timbers up onto the roof and screwing them to the plywood and also to each other.

Working on installing the rest of the timbers
Jon Wells using the loader to lift timbers on top of the blockhouse as Dimitri moves them into place
View of the blockhouse from the vertical test stand with all the timbers installed

Keith Yoerg was able to come out for the day.  He wanted to do a couple of tests on the parachute deployment charges for his upcoming launch.

Still shot from a video of Keith’s drogue parachute test

After two successful tests (drogue and main parachutes), he jumped in and helped get lumber up to the roof, cleaning the site, and helping install the trim work.  He also received a crash course in how to drive a piece of heavy machinery and drove the loader for the first time.

Keith in the loader after learning how to operate it

After the timbers were all placed and secured, the top sheeting of 11/32” plywood was screwed down to them.  Some trim work was applied to cover up the gap created by having a sloped roof.

Picture from Saturday before timbers were installed showing the roof slope
Trim installed under the sloped roof

We tried to lay down the roofing paper, but the winds picked up and we had one of the cut sheets fly off the roof twice so we decided to leave that for next time

With a little sunlight left in the day, the USC trench was filled in before the loader was taken back to the FAR site.

Dimitri filling in the “USC Trench”
Dramatic lighting as Dimitri continues to fill in the USC Trench

MTA Launch Event, 2021-10-16, First Update

by Bill Claybaugh, RRS.ORG

In a remarkable demonstration of persistence and luck, RRS President Osvaldo Tarditti was able to find the spent booster rocket. A few photos were captured of the recovered rocket.

Bill Claybaugh’s recovered spent booster casing brought back to the Mojave Test Area (MTA)
Closeup on the bulkhead shoved into the aluminum case of the booster from the impact.
The fins look great and the nozzle was recovered.

Based on the impact location, it was possible to reconstruct a possible flight trajectory by assuming the motor performed as designed and further assuming the front of the vehicle was a flat plate and that the mass did not include the mass of the payload.  We know from video, telemetry, and recovery of the payload that the payload separated from the booster about one second into the flight.

The recovery location on the map shows a northeast trajectory as confirmed by launch footage.

This analysis suggests a burnout velocity of about 1550 feet/second with a peak altitude of about 21,200 feet given the known range of about 14,300 feet. This analysis gives a flight time of about 74.5 seconds and an impact velocity of about 820 feet/second.

Given the observation that the vehicle stopped in about 2 inches (based on the depth of the depression in the hardpan) before falling on its side; we can estimate the impact deceleration.  Given an average velocity during impact of about 410 feet/second because the final velocity is zero and it took only 0.167 feet to come to rest, it follows that the impact occurred over 0.000407 seconds.  This, in turn, indicates an average deceleration of about 31,250 g’s.

The reason for the vehicle turning to the Northeast starting at about 0.20 seconds into the flight remains unclear. There is no evidence either in video or in images of the recovered hardware of any hot gas leak nor of any transient thrust vector anomaly.  The wind was less than 5 miles per hour and from the Northwest; if it had caused a turn, we would expect it to be toward the Northwest, not the Northeast as observed.  The only plausible theory at this time is that part of the belly-band became embedded between the nose of a fin and the rocket body causing the turn via differential drag and then fell away from the vehicle, causing the resumption of normal flight.  Once the recovered hardware is available for inspection, we will test each fin nose to see if a gap exists that might have caught the 0.020-inch thick belly-band.

The recovered payload segment was examined after it was found just north of the launch site.

It also remains unclear as to why the payload separated about 1 second after launch.  The recovered payload showed that both initiators had fired (by design, if one fires the other is ignited; thus, only one signal is required to fire both) but did not show any evidence of having been “swaged” or otherwise subject to being forced off the rocket by aerodynamic or other forces. Neither does the matching front end of the rocket show any evidence for the payload having been forced off. We thus conclude that one of the flight computers ordered the firing of the initiators.

The bellybands being fit checked in the launch rail.
Recovered bellybands have evidence of tearing from what is likely fin impact.

However, the main flight computer stopped working just after 0.80 seconds into the flight for an unknown reason after recovery it was still connected to its battery, which showed the expected 3.87 volts. Further, the limited data recovered from that computer shows that it did not initiate separation of the payload: the firing circuit shows continuity throughout the period that the computer was operating and separately records that no signal was sent by that computer.

Still image of the rocket just after launch making the unexpected hard turn.

This points to the backup flight computer.  That hardware is currently at the manufacture for repair, after which we hope to extract continuity data with regard to its firing status.  Hopefully, once that and other data is available from the backup computer we will be able to establish when it ordered the separation of the payload, and why.

Recovered payload with the main and backup computer.

A second update to this firing report is expected. The booster has been packaged up for a more detailed inspection.