距離地面200~600km之間的低地球軌道（Low Earth Orbit， LEO）空間，是對地觀測衛星，氣象衛星，空間站等航天器的主要運行區域，但由于地球軌道環境存在原子氧、紫外輻射、粒子輻射、高真空、等離子體、熱循環以及微流星體與空間碎片的風險，對航天器的使用壽命和穩定性存在嚴重威脅，其中原子氧、紫外輻射、高真空、真空熱循環對航天器表面材料會產生嚴重的損傷效應，影響材料尺寸穩定性、物理性能及機械性能。其中原子氧作為LEO環境中的主要組分，它具有很強的氧化性。當飛行器以軌道速度在LEO低地球軌道中運行時，原子氧以4~5eV的動能撞擊飛行器材料表面。原子氧與材料之間的相互作用會造成表面材料剝蝕以及材料性能退化，它對有機材料的腐蝕作用還會產生可凝聚的氣體生成物，進而污染航天器的光學儀器及其它設備。目前，原子氧效應研究已成為低地球軌道空間LEO環境效應研究的一個不可缺少的組成部分。

Resonance.Ltd開發的原子氧效應地面模擬實驗艙，采用采用CO2激光加熱分解產生原子氧束，可同時滿足能量為5eV和通量為3~5×10^16 atoms/cm2/s的嚴苛條件，其試驗結果與LEO飛行暴露試驗結果符合程度很高，被認為是目前實現定性和定量進行原子氧效應地面模擬的**手段。

Description:

Resonance Ltd. has developed systems to expose spacecraft materials to thermal atomic oxygen and VUV-UV light that simulates low earth orbit conditions. Oxygen atoms are produced upstream from the exposure chamber by radio frequency dissociation of O2. Atomic oxygen concentrations to 10^15 atoms/cm^3 can be generated with the high power RFX-500 generator. This is comparable to an atomic oxygen flux of roughly

2x10^16 cm^2/sec (equivalent 5 eV atomic flux measured with

Kapton dosimeter).

The oxygen density profile across the material sample can be measured in-situ with the Resonance Ltd. Atomic Oxygen Density Profiler using the technique of resonance absorption.

Resonance also provides light sources from 30 to >1，000 nm that simulate the solar spectrum. The Atomic Oxygen Density Profiler and Solar Simulator Sources can be easily adapted to existing atomic oxygen exposure systems.

AO systems from Resonance have been used by Canadian Space

Agency， by Stanford University， University of Tokyo， Los Alamos

FEATURES:

Simulates Low Earth Orbit Erosion

Samples exposed to continuous stream of thermal Oxygen atoms

High Flux

Atomic oxygen fluxes up to 3 x 10^19 atoms/cm2/sec

Quick Turn Around

Measurable erosion of Kapton by weight loss in ? hour Typical

sample exposure time is 2 hours

Solar Simulation

Calibrated Solar simulation using VUV UV and Visible light

sources and detectors

No Interferents

Samples are downstream from active plasma and are not exposed to

uncontrolled ions， metastables or UV radiation as in plasma ashers

In-Situ Atomic Oxygen Density Profile

Atomic oxygen density profile is measured by resonance absorption

of VUV line

Thermal Controlled Sample Holder

Sample holder can be heated to increase erosion rate. Thermal- vacuum cycling of the sample is also available