Radiation Metadata for GLDS Studies

Table 1 contains information used to calculate the absorbed dose of radiation for STS ("space shuttle") experiments. The absorbed dose from ionizing radiation received by the specimens (animals, plants, cells) was estimated from data recorded by three passive radiation dosimeter (PRD) packages, designated DLOC1, DLOC2, and DLOC3, in the middeck of the space shuttle, where biological payloads were located. Each package contains a number of TLD-100 thermoluminescent detectors. The TLDs are passive detectors: they integrate dose and must be processed--in the case of TLDs, by heating. (As opposed to active detectors which are powered and can be read out continuously, in real-time.) The detectors are returned post-flight and the data analysed by the Space Radiation Analysis Group at NASA-Johnson Space Center. The reported dose for each PRD is the average over all the TLDs +/- the standard deviation, with appropriate background subtraction and error propagation. Correction for dose accumulated on the ground pre- and post-flight is done by subtracting the dose in identical detectors that remain on the ground, and a calibration factor is applied to convert dose in the TLDs to dose in water.

Radiation Metadata Table 1

GLDS Accession Number
Mission STS-70 STS-108 STS-115 STS-118 STS-121 STS-126 STS-131 STS-135
Inclination 28.45 51.60 51.60 51.60 51.60 51.60 51.60 51.60
Launch/mission start 07-13-95 12-05-01 09-09-06 08-08-07 07-04-06 11-14-08 04-05-10 07-08-11
Landing/mission end 07-22-95 12-17-01 09-21-06 08-08-07 07-17-06 11-30-08 04-20-10 07-21-11
Mission duration (days) 8.93 11.83 11.81 12.76 12.79 15.87 15.10 12.76
Experiment duration (days) 8.93 11.83 1.00 12.76 12.79 14.00 12.88 12.76
Sample location Middeck (AEM) Middeck (CBTM) Middeck (GAPS) Middeck (AEM) Middeck Middeck (CGBA/FPA) Middeck (BRIC) Middeck (AEM)
Detector types Passive Passive Passive Passive Passive Passive Passive Passive
DLOC1: Absorbed Radiation Dose (mission) (mGy) 0.80 1.74 1.86 2.32 2.39 3.53 3.07 3.26
DLOC1: Absorbed Radiation Dose Uncertainty (mGy) 0.09 0.02 0.02 0.04 0.03 0.04 0.05 0.06
DLOC1: Absorbed Radiation Dose Rate (mGy/day) 0.09 0.15 0.16 0.18 0.19 0.22 0.20 0.26
DLOC2: Absorbed Radiation Dose (mission) (mGy) 1.23 2.58 2.05 3.61 3.07 5.22 3.02 5.46
DLOC2: Absorbed Radiation Dose Uncertainty (mGy) N/A 0.04 0.03 0.06 0.03 0.09 0.04 0.07
DLOC2: Absorbed Radiation Dose Rate (mGy/day) 0.14 0.22 0.17 0.28 0.24 0.33 0.20 0.43
DLOC3: Absorbed Radiation Dose (mission) (mGy) 1.08 2.24 2.67 3.52 3.06 5.54 5.18 5.26
DLOC3: Absorbed Radiation Dose Uncertainty (mGy) N/A 0.01 0.02 0.05 0.05 0.07 0.06 0.09
DLOC3: Absorbed Radiation Dose Rate (mGy/day) 0.12 0.19 0.23 0.28 0.24 0.35 0.34 0.41
Average: Absorbed Radiation Dose (mission) (mGy) 1.04 2.19 2.19 3.15 2.84 4.76 3.76 4.66
Average: Absorbed Radiation Dose Uncertainty (mGy) N/A 0.04 0.04 0.09 0.06 0.12 0.09 0.13
Average: Absorbed Radiation Dose Rate (mGy/day) 0.12 0.18 0.19 0.25 0.22 0.30 0.25 0.37
Average: Absorbed Radiation Dose Rate Uncertainty (mGy/day) N/A 0.00 0.00 0.01 0.01 0.01 0.01 0.01

 

  1. All dates are in Eastern Standard Time (EST)
  2. Note: Radiation dosimetry data for International Space Station (ISS) experiments is currently being compiled. It will be released at a future date when the compilation is complete.
  3. Note: High LET GCR contributes about 10% of the dose on ISS (up to 5% for LET>100 keV/μm) so reliance on TLDs for the Shuttle data means values could be under-reported by up to 5%.
  4. Download table as csv: radiation_data.csv
  5. Radiation exposure per experiment/study may be different from total mission radiation exposure. See each linked study record for per-study radiation exposure data.

Table 1 metadata include:

  • mission dates and elapsed mission time in days, launch to touchdown
  • sample location during the mission
  • dose rate in the PRD that recorded the lowest total dose, defined as the total absorbed dose in the detector ("dose" is synonymous with "absorbed dose in water")
  • dose rate in the PRD that recorded the highest total dose, defined as the total absorbed dose in the detector
  • average dose rate over DLOC1, 2 and 3
  • Minimum, maximum and average dose, calculated by multiplying the respective dose rates by duration of exposure to space radiation, based on experimenters' descriptions of experimental methods.

Differences between the doses recorded in the PRDs are due principally to differences in the amount of material shielding the detectors from the space radiation environment, and the doses do not take into account any shielding effects from the specimen containers or any movement of the samples around the middeck. Only Table 1 includes the individual measurements taken by all three PRDs.

Radiation metadata shown for each data set in the GeneLab Data System include:

  • Minimum, maximum and average dose for the duration of the experiment, calculated by multiplying the respective dose rates from Table 1 by the duration of the experiment, defined as the time in space during which the specimen was "living" (once the specimen was frozen or fixed, the exposure was considered stopped).
drawing of space shuttle middeck

Schematic of Space Shuttle middeck showing locations of passive radiation detectors (PRDs) DLOC1-3

PRDs were TLD-100 thermoluminescent detectors

Doses are corrected for background radiation accumulated on the ground prior to launch and between return and processing

photo of space shuttle middeck

Photo of Space Shuttle middeck showing locations of passive radiation detectors (PRDs) DLOC1-3

Data are from preliminary analysis of results from instruments on the Space Transportation Shuttle, analyzed by subject matter experts from the Space Radiation Analysis Group (SRAG), NASA-JSC. Use of the data are subject to the following rules:

  • Data shall not be redistributed internally within NASA without prior consultation with SRAG and review for export control.
  • Data shall not be distributed publicly without prior consultation with SRAG and export control of the data.
  • Publication of data shall require: