Engineering topics
Mulugeta Petros
Publications and source records attributed to Mulugeta Petros.
TPSAS-NF1676L-14096-DND
This technology development was initiated during NASA Earth Science Technology Office (ESTO) funded Laser Risk Reduction Program (LRRP) with the objective to develop a Thulium (Tm) fiber laser pumped Holmium (Ho) solid-state laser that generates laser pulses in the 2?m wavelength for pulsed CO2 DIAL/IPDA instrument. The key performance characteristics of this laser, such as energy, pulse repetition rate, pulse width, efficiency, frequency accuracy and stability, will meet or exceed the needs of the NASA Active Sensing of CO2 Emissions over Night, Days, and Seasons (ASCENDS) transmitter as currently envisioned. This space qualifiable laser architecture utilizes fiber laser and solid-state crystal laser technologies. One of the outstanding properties of the fiber laser is its efficiency. However, it inherently has low damage threshold at high energy pulses. On the other hand, the solid state laser has the capability to produce Joule-level energy at 2?m wavelength. The proposed laser combines the advantages of both lasers to provide the desired energy with high efficiency.
TPSAS-NF1676L-14130-DND
We report on remote sensing measurements of atmospheric carbon dioxide by a double pulsed 2-micron coherent differential absorption lidar technique.
TPSAS-NF1676L-18834-DND
This presentation will give an overview of the 20-plus years of pulsed transmit laser development at NASA Langley Research Center (LaRC) to enable a coherent Doppler wind lidar to measure global winds from earth orbit. Our group at LaRC has been developing the pulsed laser and other coherent lidar technologies for the global wind mission since the late 1980s. The causal path followed has been from space mission requirements to coherent lidar requirements to component requirements to technology development and finally to ground and aircraft validation. We will describe the development and deployment of Doppler Aerosols Wind Lidar (DAWN) for airborne measurement of wind velocity and direction. The will also present the status of ongoing fully conductively-cooled 2-micron wind lidar transmitter for NASA 3-D winds mission.
TPSAS-NF1676L-11930-DND
Under the NASA Laser Risk Reduction Program (LRRP), funded by Earth Science Technology Office (ESTO), an efficient, injection seeded, high repetition rate Tm:fiber laser pumped Ho:YLF laser has been developed and operation between 100 Hz to 10 kHz has been demonstrated. The work is underway to develop an efficient, high-repetition-rate, pulsed, 2-micron, coherent Differential Absorption Lidar (DIAL) / Integrated Path Differential Absorption (IPDA) instrument for measuring the atmospheric CO2 profiles (DIAL) and column densities (IPDA) from an airborne platform. In DIAL mode, this instrument will provide the first ever range-resolved, high-precision, remote measurements of the CO2 content of the atmospheric boundary layer (ABL) and lower troposphere.
Independent Reliability Assessment of the NASA GSFC Laser Transmitter for the LISA Program
The Laser Interferometer Space Antenna (LISA) is a partnership between the European Space Agency (ESA) and NASA to build a Gravitational Wave (GW) observatory. The observatory, which consists of a three-spacecraft constellation with a nominal separation of 2.5 million km between each spacecraft, provides a tool for scientists to directly detect gravitational waves generated from various astronomical phenomena in a waveband that is not accessible from Earth. NASA is developing laser transmitters as one of the potential US contributions to LISA. The NASA laser design leverages lessons learned from previous flight missions and included the latest technologies in photonics packaging and reliability engineering to ensure a laser lifetime of >16 years covering integration and test through a possible extended mission phase. As part of the laser development process, NASA’s Goddard Space Flight Center (GSFC) requested support from the NASA Engineering and Safety Center (NESC) to independently assess the Technology Readiness Level (TRL) of the LISA Laser System (LS). The independent assessment included the following tasks: (a) assess the design for weaknesses and suggest improvements to mitigate risks, (b) assess the laser reliability plan for weaknesses and suggest improvements to mitigate risks and improve effectiveness, and (c) assess the current redundancy plan on laser subsystems for weaknesses and suggest improvements to mitigate risks and improve effectiveness. The NESC team comprised of a team of subject matter experts (SMEs) and performed a 12-month review of every aspect of the laser design. We present the assessment findings and the current development progress of the LISA laser to meet the mission requirements with a delivery of a form, fit, and functional TRL6 laser to the LSIA mission by late 2023.
Independent Reliability Assessment of the NASA GSFC Laser Transmitter for the LISA Program
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Independent Reliability Assessment of the Laser Transmitter for the ESA‐NASA Laser Interferometer Space Antenna (LISA) Program
Explore the source record for details and available documents.
Independent Reliability Assessment of the Laser Transmitter for the ESA-NASA Laser Interferometer Space Antenna (LISA) Program
As part of the laser development process, NASA’s Goddard Space Flight Center (GSFC) requested support from the NASA Engineering and Safety Center (NESC) to independently assess the Technology Readiness Level (TRL) of the LISA Laser System (LS). The independent assessment included the following tasks: (a) assess the design for weaknesses and suggest improvements to mitigate risks, (b) assess the laser reliability plan for weaknesses and suggest improvements to mitigate risks and improve effectiveness, and (c) assess the current redundancy plan on laser subsystems for weaknesses and suggest improvements to mitigate risks and improve effectiveness. The presentation will focus on the assessment findings and the current development progress of the LISA laser to meet the mission requirements with a delivery of a form, fit, and functional TRL6 laser to the LISA mission by late 2023.