EUSO BALLOON phase A review CNES, Mechanical design of the instrument approach for integration and tests Peter von Ballmoos, IRAP Toulouse

EUSO BALLOON instrument overview data processing Photo detection optical system

Payload architecture - conventions PDM Platform 3 / lens 3 Platform 2 / lens 2 Platform 1 / lens 1 grooved surfaces z x y

Constraints on the instrument/gondola design optics : "12° (± 6°) of Alex "adopted to 95% by the "optics team" - allowed tolerances vary from 0.2–4 mm (axial) 1-5 mm (lateral) for the 3 lenses. - lens 3 has to be adjustable in z-direction by ± 2 cm - distance between PDM-optics has to be adjustable by ± 2 - precision of distance PDM-optics is ± 1 mm thermal : - lens1 might get expose to temperatures as low as -60°C - PDM and lens 2&3 should remain between 10°C and 20°C (TBC) - need for cooling of the PDM is not to be excluded at this point. - avoid condensation and ice on lenses (particularly lens 3) operations : - "integrity" requirement at the parachute opening 10g/5g - prepare for recovery at sea

Alignment of the lenses and the PDM - tolerances Objective : as representative as possible for JEM-EUSO design with short focal lenght (1.48 m) and fairly large FOV of ± 6° ~ 1,48 m 1 x 1 m ± 4.2mm ± 2.7mm ± 0.2mm z tolerances TBC x,y tolerances TBD tilt tolerances TBD ± 0.2mm

Alignment of the lenses and the PDM ~ 1,48 m 1 x 1 m ± 20 mm (res ± 0.1mm) 1) Platform 1 and platform 2 are directly fixed within the phone booth 2) Lens 3 shifts in z-direction by ± 20 mm 3) Distance - optics block (lens-1-2-3) is adjustable within ± 20 mm Objective : as representative as possible for JEM-EUSO design with short focal lenght (1.48 m) and fairly large FOV of ± 6° ± 20 mm (res ± 0.1mm) ± 1 mm

The mounting and alignment of the Fresnel lenses The mounting of the lenses has to satisfy the following requirements : a) minimize lens sag b) optical alignment compatible with to the tolerances required c) phonebooth must be watertight d) lens thermal expansion/retraction e) stability/simplicity

The mounting and alignment of the Fresnel lenses plug+ (seal) platform (bulkhead) gasket lens spider

a) lens sag : the four arms of a spider shall support the only 8 mm thick PMMA lens to minimize deformation under its own weight. b) alignment : - axial reference (in z-direction) : inward pointing surface of the spider length of the "nose" defines distance to platform - lateral reference (x,y-directions) : "plug" in the center of the spider. lens spider platform z-reference plane nose-length The mounting and alignment of the Fresnel lenses

c) watertight : - seal between lens and platform makes phonebooth watertight. at least lens 1 and 2 – lens 3 is mounted "from above" and might not need to be watertight. d) lens thermal expansion/retraction: - the lens is fixed in its center - only weakly constrained for expansion/retraction within the x-y plane. - pressure provided by the seal allows for minute movements related

the architecture of the EUSO-BALLOON instrument

integration and tests integration at IRAP Toulouse, clean/balloon hall G. Roudil, IRAP verification of geometry by use of a laser tracker - B. Mot, IRAP tests of imaging/PSF by use of IRAP collimators/lasers (in case the optics do not go to MSFC)

RISKS Failure of mechanical subsystem RI2.1 Fresnel lenses not matched by platform mechanics Spider or Lenses can be re-machined easily RI2.2 Fresnel lens(es) damaged or polluted during integration Lenses will be protected at any time, Protection removed for launch RI3.2 Project exceeds available M/power resource envelope Phase A to define tasks, organization and necessary manpower. Phase A review to assess this point.

A roof-rack for the Bells and Whistles roof-rackIR-cameralaser

last but not least : recovery at sea

water-landing (not for first flight)

"stabilized" gondola (LPMA, 2003) The period of the oscillations is typically in the order of 20 s.

motto for scientific ballooning "Success is the ability to go from failure to failure without losing your enthusiasm"Churchill

Mechanical functional block scheme (from Casolino et al.)

Payload architecture – thermal aspects fibrelam panels painted white styrofoam ?

anel-Data-Sheets/Fibrelam_global.pdf

Payload architecture – thermal aspects thermal cover inside black outside white

electronics functional block scheme – harness ? from "dossier de definition" Marco Casolino et al. 10/2011