FlaPS and WISPERS

Researchers in the US have developed a tiny analyser to study depletions of plasma (known as plasma bubbles) in the ionosphere, a phenomenon that can disrupt satellite communications.

The Flat Plasma Spectrometer (FlaPS) is one of three experimental payloads onboard the US Air Force Academy’s Falconsat-3 microsatellite that launched recently on an Atlas V from Cape Canaveral Air Force Station, Florida. The six-month mission is demonstrating an improved technology to help the air force better understand and forecast plasma bubbles.

Conceived by NASA Goddard Space Flight Center and the Air Force Academy, and designed and fabricated by Johns Hopkins University Applied Physics Laboratory (APL), FlaPS reduces a plasma spectrometer from the size of a coffee urn to that of a teacup.

‘We’ve aggressively miniaturised the instrument by applying manufacturing techniques used in the micro-electronics world to build personal computer components,’ said Robert Osiander, APL’s principal investigator for the FlaPS program.

Although the instrument is not unique in terms of its science data, it is unique in terms of its size, which can help reduce overall mission costs. ‘We’ve applied MicroElectroMechanical (MEMS) technology to reduce the instrument’s size by a factor of 100 while greatly increasing its sensitivity and resolution, and dramatically reducing weight and power requirements compared to conventional spectrometers,’ said Danielle Wesolek, APL’s technical lead for FlaPS.

If viewed through an electron-scanning microscope, a hole smaller than the width of a human hair appears and this is where particles enter the spectrometer. As particles travel through the electrostatic analyser, or energy selector, they pass through another small opening. The opening leads to a series of tiny parallel plates that deflect the particles toward the exit from this section of the analyser. Only particles of a selected bandwidth pass through and are collected. Data is then downlinked to science teams on the ground through Falconsat-3’s mission operations centre located at the Air Force Academy.

The spectrometer’s small size, low weight and power consumption, and increased resolution make it suitable for use in large numbers, and could be applied to other types of missions.

‘These spectrometers could be advantageous for mapping missions, for example, which require a large number of microsatellites to simultaneously map multiple points in space,’ said Osiander. ‘Where we once could only carry one spectrometer per spacecraft, we can now carry dozens.’

The multi-organisational team is already working on the next-generation device known as WISPERS (Wafer-scale Integrated SPectrometERS), an instrument suite created by the same micro-electronics-based manufacturing techniques.

WISPERS is scheduled to fly on Falconsat-5 scheduled for launch in the autumn of 2009.