NASA’s Dragonfly mission will sample surface materials from multiple sites on Saturn’s largest moon, Titan, in exploration of prebiotic chemistry. We report on the performance of our short-pulsed UV laser transmitter, developed for the Dragonfly’s on-board Mass Spectrometer (DraMS). Our Engineering Test Unit (ETU) has completed flight qualification and demonstrated its operational science requirements, such that the final spaceflight unit build can begin. The Titan Hydrocarbon Analysis Nanosecond Optical Source (THANOS) ETU laser produces 266 nm laser pulses at programmable energy levels to perform high resolution Laser Desorption Mass Spectrometry (LDMS) measurements. The laser operates in bursts of one to 50 pulses, each at ⪅ 2 ns pulse width with a pulse energy of 0 - 200 uJ, at a 100 Hz repetition rate. This paper details the qualification process of the THANOS laser as well as the rigorous characterization performed to ensure consistent performance of the system during laboratory testing, while integrated onto the DraMS instrument and most critically, while operating on the distant surface of Titan.
The Global Ecosystems Dynamics Investigation (GEDI) Lidar, is a global three-dimensional biomass lidar instrument aboard the International Space Station (ISS) and the Japanese Experiment Module (JEM). Its core mission is to measure the global carbon balance of Earth’s forests with three laser transmitters using multi-beam waveform-capture methods. GEDI’s laser transmitter concept was originally funded by NASA Goddard’s Earth Science Technology Office (ESTO) for future Earth Altimetry and Lidar missions approximately 20 years ago, and after a winding story of stops and starts, the first flight-ready transmitter was a 10 mJ-class system for GEDI’s ISS-based specifications. Furthermore, no adjustment in drive parameters has been required nor significant decay detected after four years of near continuous operation of three on-board lasers, designed for a two-year mission. We present an overview of the GEDI laser development process, report on their mission performance, the major lessons learned, and some critical insight into our in-house flight quality development process that enabled their delivery within budget, schedule, and low risk extended mission life capability.
NASA’s Dragonfly mission is a rotorcraft lander which will explore several geologic locations on Saturn’s moon, Titan and investigate evidence of surface-level prebiotic chemistry as well as search for chemical signatures of water-based and/or hydrocarbon-based life. To perform molecular composition investigations in-situ, the payload includes the Dragonfly Mass Spectrometer (DraMS), being developed at NASA’s Goddard Space Flight Center (GSFC). DraMS will utilize laser desorption mass spectrometry (LDMS) to interrogate surface samples and measure the organic composition. Enabling this science capability is the Throttled Hydrocarbon Analysis by Nanosecond Optical Source (THANOS) laser being developed at NASA-GSFC. The THANOS laser is comprised of a solid state, passively Q-Switched Nd:YAG oscillator which is frequency converted to 266 nm and utilizes a RTP high voltage electro-optic for pulse energy control. The laser outputs <2.0 ns pulses with a maximum energy of approximately 200 uJ which can be emitted in 1 - 50 shot bursts at 100 Hz while performing LDMS science operations. The laser has the capability to throttle its UV pulse energy output from full attenuation to maximum energy to provide varying levels of fluence on samples in the DraMS instrument. We report on the THANOS’ laser technology development and space qualification effort including vibration, thermal vacuum cycling, radiation as well as optical damage testing due to Titan’s atmospheric composition, performed at NASA-GSFC from 2019 through 2022.
The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solidstate 266-nm pulsed Nd:YAG laser to perform compositional analysis on the surface of Titan. Due to the high fluence of the focused pulse energy on the laser’s beam steering unit (BSU) and the mass spectrometer window, the damage threshold of these optics in a Titan atmosphere needed to be characterized. This paper details the test setup and the successful demonstration of testing the highest fluence optics for the expected mission duration of 2 million laser pulses in a Titanrelevant atmosphere.
NASA’s Dragonfly mission will sample surface materials from multiple sites on Saturn’s largest moon, Titan, in exploration of its potential for prebiotic chemistry. We are developing and delivering a compact pulsed UV laser transmitter, developed in-house at NASA’s Goddard Space Flight Center, capable of directing programmable 266 nm pulse energies to a small sample of surface material for laser desorption mass spectrometry (LDMS) performed by the on-board Dragonfly Mass Spectrometer (DraMS). The mail goal for this effort was to develop a flight-capable, two-part design, employing a remotely located fiber coupled pumping source, and a UV transmitter unit that can operate in short bursts with minimal change in laser pulse characteristics such as beam quality, pointing, energy, and pulse width. The DraMS UV source will require a 7+ year transit to the Saturn system; where upon deployment on Titan’s surface, must demonstrate a combination of survivability, reliability, operational capability, and performance yet developed in a flight-qualified solid-state laser transmitter. Once Dragonfly is safely operational, the Titan Hydrocarbon Analysis Nanosecond Optical Source (THANOS) UV laser will perform for 3+ years in Titan’s extreme surface and atmospheric conditions in several locations.
The Global Ecosystems Dynamics Investigation (GEDI) Lidar, is an Earth Science remote sensing instrument aboard the International Space Station (ISS) and the Japanese Experiment Module (JEM). Its core mission is to measure the global carbon balance of Earth’s forests by using a set of three solid state laser transmitters in a multibeam waveform capture lidar technique. GEDI’s laser transmitters and precision optical system transmits over 3.4 million laser pulses to the Earth every hour, each pulse producing an individual 3-D biomass column measurement. To enable a successful two-year mission, the lasers had to be reliable, highly repeatable in performance with each measurement power cycle, and designed with minimal part count for reduced manufacture complexity and cost. These transmitters are in-house products; developed, constructed, qualified, and fully integrated into the GEDI instrument at NASA’s Goddard Space Flight Center. We will present the lasers’ path from initial design to flight operation, with emphasis on the major milestones, critical issues, and lessons learned. Full credit goes to the excellent team effort that led to the successful commissioning and initiation of full-time science operations in March 2019.
Ultra-compact, nanosecond-class spaceflight-compatible UV lasers are finding increasing application in laser desorption, excitation, and ionization analytical applications on planetary missions, such as the detection and characterization of potential molecular biosignatures on Mars or icy moon surfaces. A short pulsed, solid state, UV laser is under development with selectable pulse energy capabilities for optimized sample ion production at a planetary surface.
Paul Stysley, D. Coyle, Furqan Chiragh, Erich Frese, Michael Hersh, Kevin Smith, Gordon Blalock, Peter Morey, Juan Lander, Richard Kay, Demetrios Poulios, Greg Clarke, Kristen Washington, Cindy Kirchner, Pete Mule
The Global Ecosystems Dynamics Investigation (GEDI) Lidar Mission will employ three lasers systems internally developed, built, and tested by the NASA Goddard Space Flight Center Lasers and Electro-Optics Branch. Once installed on the Japanese Experiment Module (JEM) on the International Space Station (ISS), the lasers, each coupled with a Beam Dithering Unit (BDU) will produce three sets of staggered footprints on the Earth's surface to accurately measure global biomass. Each of the lasers is a heritage Nd:Yag solid state design required to put out Q-switched pulses at a rate of 242 Hz with a minimum 10 mJ per pulse at a 1064 nm wavelength. During the project, an engineering test unit (ETU) was also built and tested to pave the way for the laser systems to be used in space. We report on the technical and programmatic requirements that drove the design and development of the lasers. Also presented is an update of the performance of the engineering test unit qualification and life-testing along with the status of the space flight lasers.
Flight quality solid-state lasers require a unique and extensive set of testing and qualification processes, both at the system and component levels to insure the laser's promised performance. As important as the overall laser transmitter design is, the quality and performance of individual subassemblies, optics, and electro-optics dictate the final laser unit’s quality. The Global Ecosystem Dynamics Investigation (GEDI) laser transmitters employ all the usual components typical for a diode-pumped, solid-state laser, yet must each go through their own individual process of specification, modeling, performance demonstration, inspection, and destructive testing. These qualification processes as well as the test results for the laser crystals, laser diode arrays, electro-optics, and optics, will be reviewed as well as the relevant critical issues encountered, prior to their installation in the GEDI flight laser units.
The Lasers and Electro-Optics Branch at Goddard Space Flight Center has been tasked with building the Lasers for the Global Ecosystems Dynamics Investigation (GEDI) Lidar Mission, to be installed on the Japanese Experiment Module (JEM) on the International Space Station (ISS)1. GEDI will use three NASA-developed lasers, each coupled with a Beam Dithering Unit (BDU) to produce three sets of staggered footprints on the Earth's surface to accurately measure global biomass. We will report on the design, assembly progress, test results, and delivery process of this laser system.
The Global Ecosystems Dynamics Investigation (GEDI) Lidar, to be installed aboard the International Space Station in early 2018, will use 3 NASA laser transmitters to produce 14 parallel tracks of 25 m footprints on the Earth's surface. A global set of systematic canopy measurements will be derived, the most important of which are vegetation canopy top heights and the vertical distribution of canopy structure. Every digitized laser pulse waveform will provide 3-D biomass information for the duration of the mission. A total of 5 GEDI-HOMER lasers are to be built (1 ETU + 3 Flight + 1 spare) in-house at NASA-GSFC, and is based on a well-studied architecture, developed over several years in the Lasers and Electro-Optics Branch.
KEYWORDS: Ranging, Laser systems engineering, Space operations, Optical tracking, Laser applications, Reflectors, Satellites, Space telescopes, Telescopes, Data modeling
The mitigation of orbital debris was addressed in the most recent release of the National Space Policy directing space
faring agencies to pursue technologies that will “mitigate and remove on-orbit debris.” No matter what abatement
technology is developed and deployed, still lacking is the remote sensing infrastructure to locate and track these objects
with adequate precision. We propose using GSFC's ground-based laser ranging facility to provide meter-level or better
ranging precision on optically passive 10-30 cm orbital debris targets with the goal of improving current predictions up
to 85%. The improved location accuracy also has the immediate benefit of reducing costly false alarms in collision
predictions for existing assets.
A fiber/solid-state hybrid seeded regenerative amplifier capable of achieving high output energy with
tunable pulse widths has been developed for satellite laser ranging applications. The regenerative amplifier
cavity utilizes a pair of Nd: YAG zigzag slabs oriented orthogonally to one another in order to symmetrize
thermal lensing effects and simplify optical correction schemes. The seed laser used is a fiber-coupled
1064 nm narrowband (<0.02 nm) diode laser which is intensity modulated by a fiber Mach-Zender electrooptic
modulator, enabling continuously tunable seed pulse widths in the 0.2 - 2.0 ns range. The seed laser
pulse energy entering the regenerative amplifier cavity is ~10 pJ, and is amplified to ~1.6 mJ after 37 round
trips, representing a gain of ~82 dB. When seeded with 200 ps pulses at a 2 kHz repetition rate, the
regenerative amplifier produces >2 W of frequency-doubled output (>1 mJ/pulse at 532 nm).
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