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Table 2 Spacecraft zone-wise comparison about the different bioburden assays

From: Application of the ATP assay to rapidly assess cleanliness of spacecraft surfaces: a path to set a standard for future missions

Zone Name

ATP assay

NASA standard spore assay

# of samples tested using swabs

Percent clean samples (<2.33 × 10−11 mmol ATP)

Percent dirty samples (≥2.33 × 10−11 mmol ATP)

# of samples tested using:

Percent clean samples (<1 spore)

Percent dirty samples (≥1 spore)

Swabs

Wipes

Backshell

21 (4)a

81.0

19.0

9 (1)

11 (7)

60.0

40.0

Descent stage

100 (9)

91.0

9.0

109 (1)

32 (4)

96.5

3.5

Heatshield

21 (7)

66.7

33.3

6 (6)

100.0

Rover

107 (15)

86.0

14.0

87 (1)

18 (2)

978.1

2.8

  1. aNumeral in parentheses denotes # of samples exhibiting more than the threshold level of cleanliness