Lasers in Space Series Part 1: Guide Stars, R & D and Hardware Orientation
The Lunar-Ranging experiment in the 1960s was the very first instance of lasers being used in space technology. Since then, lasers have been an essential part of space exploration, satellite-based R & D, communications and sample analyses. In this first part of our 2-part series on lasers in space, we take a look at Laser Guide Stars, the various ways in which lasers may be used for a mission's real-time research and hardware / component orientation in space.
Laser Guide Stars are part of 'Adaptive Optics' technology, which is a technique to sharpen the image of distant objects in space when viewed from a telescope. When light from stars travels through layers of the atmosphere, turbulence causes it to get blurred. Lasers are used to create an artificial star or 'guide star' that provides a relatively fixed point in space. The laser beam gets distorted when viewed from earth, and adaptive optics corrects this distortion. A supercomputer measures the changes in the laser beam and conveys them to a deformable mirror. When the 'bent' light from the artificial star reaches the mirror, the supercomputer deforms the mirror so that the reflecting light's wave is straightened. These same adjustments can be used to construct a sharp image of neighboring planets and stars.
The past two decades have seen a huge increase in the use of lasers in several space research proposals. One NASA initiative focuses on atmospheric analysis, using laser-equipped satellites to study the amount of carbon dioxide, water vapor and suspended particular matter in the air. The aim is of the study is to gather enough data to take action for the long term health of the ozone layer. Another widely reported use of high-powered lasers is for spectroscopic analysis of surface materials on different planets, for example, the infrared diode laser on the Mars rover Curiosity. Other research proposals are currently focusing on many novel applications, such as using lasers for space-debris clearing, gravitational wave detection, laser-powered rocket propulsion and dramatically increasing data-relay speeds from space-crafts to earth.
Accurate orientation of components and hardware is critically important to mission safety. Lasers are exclusively used to provide precise alignment of parts and components during vehicle assembly (similar to aircraft manufacturing) and low powered lasers are also carried on board to monitor the positions of components or experimental tools during the mission. Laser Metrology is the science behind using lasers for precise measurement in space. Some examples are rendezvous and docking in space flights.
Laserglow is constantly being challenged to provide laser solutions for applications in space. Space vehicle designers and contractors often use our Brightline lasers in the assembly process, and some use them for in-flight alignment confirmation and position monitoring.
Biological research continues to be a large arena for our laboratory laser deployment, and we'll cover this in greater detail in part 2 of our 'Lasers in Space' series.
1. 'Lasers Find Varied Uses in Space Applications' - Valerie C. Coffey, Photonics Spectra, Aug, 2012: Online Link-Photonics.com
2. 'Laser Technology: Shedding Some Light'- NASA Langley Media and Public Outreach, December 1996: Online Link-NASA Media
Capillary-Electrophoresis Enhances Cell Studies with Laser-Induced Fluorescence
Researchers at Columbia University in association with the University of Illinois have proposed a new method to measure quantities of reactive oxygen species (ROS) and glutathione (an anti-oxidant) inside a single cell, immediately after these are formed when a charged particle traverses the cell. The researchers aim to study gene expression and cell-chemistry with this method, and quantifying ROS and glutathione is the first phase of their study. Laserglow's 473 nm laser (LRS-0473) was used as the light source in the experimental setup.
Individual cell studies focus on analyzing the components of a cell after it has been treated with a chemical stimulant. When combined with a micro-beam, cell analysis techniques allow researchers to target and analyze a single cell to gain a better understanding of the responses caused by laser irradiation. The method in this research is based on Capillary-Electrophoresis (CE) coupled with Laser-Induced Fluorescence (LIF).
CE is a technique that separates ions based on their characteristic electrophoretic mobility1 under an applied voltage. LIF is based on irradiating a sample with laser light of a specific wavelength, then collecting and measuring the fluorescence emission, usually combined with a spectrometer. The CE-LIF setup has a thin capillary (50 micron bore) through which the single cell travels when irradiated by the micro-beam. The capillary is then removed and placed in a vial containing background electrolyte. The cell deconstruction and separation into components happens inside the capillary once a high voltage is applied between the vial and detection system. The components are then analyzed in more detail by applying a laser just below the capillary output to irradiate it, and the fluorescence is collected and analyzed by an image capturing system.
To learn more about the experimental setup, and see how the first phase of this study relates to gene expression, read the paper at:
Columbia Full Paper
1 - Electrophoretic mobility is the measure of the characteristic speed at which ions migrate towards an electrode in a liquid medium. It depends on the charge of the ion, viscosity and atom's radius.
Atomic Laser Developed With Shortest Wavelength Yet
Researchers in Japan have demonstrated an atomic laser that has the shortest wavelength yet at 0.15 nm. The research, first published in the journal Nature, describes the development procedure in detail as well as the methodology and purpose behind this undertaking.
X-rays have proved to be invaluable in the field of medical diagnostics, as they are able to penetrate through skin, tissue and bones and then provide a contrast between different body parts, owing to their magnetic, chemical or elemental properties. As early as the 1960s, the idea of an atomic x-ray was developed with the intent of viewing images at a molecular level. Researchers proposed using laser light with a suitable optical wavelength to achieve this. However, there was still a need to produce even shorter wavelengths to generate coherent x-rays, because the shorter the wavelength, the better the resolution of the imaging device.
This latest development allows for shorter pulses of light and hence provides excellent resolution in probe measurements. There is still a limitation on how short a wavelength can be achieved, as this technique require a very high power to operate. Researchers have been able to overcome this by using free-electron type lasers that are based on self-amplified spontaneous emissions. While still in early stages of development, experts believe that this research could lead to unparalleled cellular, molecular and atomic resolution, and atomic measurement capabilities. Read more at
Phys.org full article