EUSO BALLOON phase A review CNES, 2.2.2012

Mechanical design of the instrument

approach for integration and tests

Peter von Ballmoos, IRAP Toulouse

EUSO BALLOON instrument overview

data

processingPhoto

detection

optical

system

Payload architecture - conventions

 PDM  Platform 3 / lens 3 

Platform 2 / lens 2 

Platform 1 / lens 1

grooved surfaces

z

xy

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 m1 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 m1 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 ± 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.

lenslens

spiderspider

platformplatform

z-reference plane

nose-length

The mounting and alignment of the Fresnel lenses

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

the architecture of the EUSO-BALLOON instrument

the architecture of the EUSO-BALLOON instrument

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 ofa laser tracker - B. Mot, IRAP

tests of imaging/PSFby 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 panelspainted white

styrofoam ?

http://www.hexcel.com/Resources/DataSheets/Panel-Data-Sheets/Fibrelam_global.pdf

Payload architecture – thermal aspects

thermal coverinside blackoutside white

electronics functional block scheme – harness ?

from "dossier de definition" Marco Casolino et al. 10/2011