BARREL 2008/2009 Piggyback Flight

A. cutdown and post-flight materials

The flight was terminated at UT 03:04:45 20Feb09. We continue to collect data from the payload ground location latitude: -79.8642, longitude: -45.4484, altitude: 746 m.

UPDATE: last payload contact at UT 23:42 7Mar09

quick-look pdf plots from the descent phase and after

memo from CSBF about the flight

From: Dwayne Orr/CSBF Deputy Site Manager
Subject: Flight Summary - Flight No. 591 NT
Date:  19 February 2009

Flight Number: 591 NT
Organization/Experimenter: NASA-WFF-BPO / David Pierce
Description:  ULDB (Ultra-Long-Duration Balloon) 7-MCF Test
This is the ninth in the series of ULDB test flights, and the third test of the revised super-pressure pumpkin balloon design. The test article is a 6.89-MCF scaled version of the ULDB.  The test will be to demonstrate the ability of ground personnel to prepare and launch the super-pressure pumpkin balloon, as well as to deploy, maintain altitude, and fly the balloon at operational pressures.
Date/Time Launched: 28 December 2008 / 02:30:00 Z
Balloon: A6.89-1.5U1-02
CSBF Balloon Number: 1034
Mil Thickness (Shell/Caps):  1.5/0.8
Balloon Weight: 2374 lbs.
Experiment Weight: 1,500 lbs.
Suspended Weight: 1,500 lbs.
Gross Inflation: 4,261 lbs.
Free Lift: 10%
Float Altitude: 112.2 Kft
Terminate Date / Time:  20 February 2009 / 03:04:45 Z
Impact Date / Time:  20 February 2009 / 03:59:16 Z
Location of Impact:  79-51.85 South / 45-26.92 West (1280 nm south southeast of McMurdo Station on Berkner Island)
Total Flight Time (Hours, Minutes):  54 days 1 hour, 29 minutes
Condition of Payload: Good (estimated)

Remarks:  This flight was an operations and science success.  All ULDB minimum and desired pre-flight requirements were met and/or exceeded.  The launch, ascent, float, termination, and parachute separation were within nominal parameters.  The ULDB vehicle maintained a pressurized state throughout the entire 54 day record breaking flight.  Also, the new Micro Instrumentation Package (MIP) performed exceptionally well throughout the flight.  An Over the Horizon (OTH) termination using Iridium was completed.  The parachute cut away was successfully performed using the Semi-Automatic Parachute Release (SAPR) system.  Post impact Iridium telemetry indicates that the gondola remained upright after impact, with little probable damage.

B. main flight materials

quick-look pdf plots from the piggyback flight

balloon track

The following show x-ray fluxes. The IRQ (dpu interrupt) rate counter is accurate over the count rates we have. The LL (low level) and PD (peak detect) counters roll over when the count rate exceeds 5100 per second. The fast spectrum channels cover energy ranges 10--180 keV (blue), 180--550 keV (green), 550--840 keV (yellow) and 840--1500 keV (red). The 3Jan events are low energy.
The 14/15Feb spectra show lots of activity, including some high energy fluxes. Look at 15Feb 12:30, where an atmospheric line near 5MeV was excited.
plots of TCM3 errors: These were made by finding instances for which Bz differed from its smoothed trace by at least 5 uT. There are 2 interesting features in the figures: first, when Bz jumps, so also do the other 2 components; second, bad measurements frequently appear as consecutive measurement pairs.

C. pre-flight materials

The CVI distribution kit for the UW testing gse uses the PC COM1 port. A cable between the piggyback instrument and PC connects the TX, RCV, and GND lines from the PC to the interface board in the DPU box.

A toggle switch in the gui mimics the CARRIER/NO CARRIER messages and sends the RCVD signals to the DPU at 10 second intervals when a connection is present. This version works with 200 byte frames only. Another recent feature is that, when started, the software begins storing frame data in a file named for the start time (YDDDHHMM.dat).

The zip file includes the source code, the uir file, and an executable at the top level. This means a full installation is not necessary if the PC already has CVI software installed.

  • zipped distribution kit and source code for UW test gse
  • DPU box drawing, a half scale pdf drawing of the dpu box

    Here are some plots from CSBF testing.

    Typical count rates should be on the order of 200 counts/second. We do not see this at the hang test. Instead count rates are 20 to 50 times higher than the expected background rates. We do see typical background count rates for the files taken prior to the hang test. This shows best in the blue (IRQ) rate counter trace, taken from a 16-bit wide counter that is read once per second. That means it can count to 65K/second without overflow. The other 3 counters are 8 bits wide and are sampled 20 times/second. Hence, they overflow when the count rate exceeds 5K/second. This is a holdover from MINIS that will be changed for BARREL. Ideally IRQ=PD and LL is slightly larger than PD. HL should be small, and is.

    For the time prior to hang test, the spectra show features compatible with a local thallium-201 source, having a slight thallium-202 contamination, when the count rates are high. This same kind of spectrum was also present during the hang test. It is reasonable to assume that most, if not all, of the high count rate is due to the thallium source, and not due to instrumental problems. However, since the thallium source was always present in the hang test, we don't yet have unambiguous evidence that all is well.

  • rate counters prior to hangtest
  • rate counters from hangtest
  • counter comparison prior to hangtest
  • counter comparison from hangtest
  • spectra prior to hangtest Five 5-minute spectra accumulations; color codes for time with blue earliest running through the rainbow to red latest.
  • spectra from hangtest Five 5-minute spectra; color coding as before.