Environmental assessment in the prelaunch phase of Hayabusa2 for safety declaration of returned samples from the asteroid (162173) Ryugu: background monitoring and risk management during development of the sampler system

Earth, Planets and Space

Table 4 Concentration of total organics from static and air-filter sampling during sampler-system development up to the launch of the Hayabusa2 spacecraft

Sample code	Profile	Days	Concentration total organics			Remarks
Sample code	Profile	Days	ng/sample	ng/cm²	ng/cm²/day	Remarks
Static sampling
CAS-01	CC1-Al	368	1796	254	0.69	Please see, Fig. 1b, c and Sawada et al. (2017)
CAS-02	CC2-Al	73	388	55	0.75
CAS-03	CC3-Al	83	345	49	0.59
CAS-04	CC4-Al	79	864	122	1.55
CAS-05	CC5-Al	20	464	66	3.29
CAS-06	CC6-Al	69	1049	149	2.15
CAS-08	CC8-Al	23	320	45	1.97
CAS-09	CC9-Al	14	422	60	4.27
CAS-10	CC10-Al	17	346	49	2.88
CAS-12	CC12-Al	15	180	25	1.70
Air filter sampling
QFT-01	20141024-QF-01-#1		588	83		Quartz filter at STA1
QFT-02	20141024-QF-06-#1		425	60		Quartz filter at SFA2
QFT-03	20141024-QF-11-#1		978	139		Quartz filter at VAB
Swab sampling
Jet deposit	After jet experiment		–	12

Static concentrations were normalized in units of nanograms per sample (ng/sample) following Takano et al. (2020). The concentrations of area-based conversions (i.e., ng cm⁻²) can be obtained by reference to the size scale (Fig. 1). The swab sampling during the jet deposit (i.e., thruster test of the aircraft; Tsuda et al. 2013) was assessed by subtracting the value between the experimental deposit and the background (i.e., ng cm⁻²)