Engineering topics
Publications and source records attributed to Matthew W Mullin.
The Global Ecosystems Dynamics Investigation employs three laser systems delivered by NASA Goddard Space Flight Center. We report on the status of these systems after over 2 years and 10 billion shots in orbit.
The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solid-state 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 Titan-relevant atmosphere.
The in Situ Spectroscopic Europa Explorer (iSEE) instrument is an ultra-compact laser-enabled Raman spectrometer instrument that meets the top-level science requirements for multiple future planetary in situ missions to explore the surface and atmospheric chemistry of planetary bodies across the Solar System. Enceladus, Europa, the Moon, Mars, and Venus are some of the primary targets for future NASA missions to search for extraterrestrial life and potentially habitable environments beyond Earth, further our understanding of the timing and formation of the Solar System and identify potentially viable economic resources such as water and/or valuable metal assets. We report on the advancement and space flight qualification of a compact, robust, solid-state laser operating at 515 nm that serves as the excitation source for the iSEE investigation. The iSEE instrument is being developed under a NASA Maturation of Instruments for Solar System Exploration (MatISSE) program. The iSEE laser is a diode pumped 1030 nm Yb:YAG microchip laser with a second harmonic generator to achieve an output wavelength of 515 nm and coupled to a multi-mode fiber for delivery to the Raman spectrometer probe. The fundamental 1030 nm laser operates at a pulse repetition frequency (PRF) of 1-10 kHz with pulse energy of 95 μJ and ~800 ps pulse width. A 15 mm long Type II KTP crystal is used for second harmonic generation from 1030 nm to 515 nm. The residual fundamental 1030 nm is separated from the 515 nm beam using a pair of dichroic filters. A focusing lens couples the 515 nm beam to the optical fiber to produce an output laser pulse energy of 20 μJ. A custom vacuum fiber feedthrough assembly was designed with two 105 μm core fibers, and two 200 μm core fibers. One fiber is needed for coupling the laser to the iSEE instrument, and the additionally fibers provide redundancy and design flexibility. The laser enclosure is pressurized with >1 atm of clean dry air. The laser has been designed to minimize the size, weight, and power (SWaP) for a lander instrument with minimal resources. The laser will go through environmental testing including vibration and thermal vacuum testing for space flight qualification. Here we discuss the design, trade studies, performance, and environmental qualificationtesting of the iSEE laser.
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. While operating, 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. This paper reports the technology development and space qualification effort of the THANOS laser including vibration, thermal vacuum cycling, radiation as well as Titan atmospheric composition optical damage testing performed at NASA-GSFC from 2019 through 2022.
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 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 flight unit build can begin. The Titan Hydrocarbon Analysis Nanosecond Optical Source (THANOS) ETU laser produces 266 nm laser pulses at programmable energy levels in order to create high resolution laser desorption mass spectrometry (LDMS) measurements. The laser operates in short bursts of 1-50 pulses, each at < 2 ns pulse width, at a 100 Hz repetition rate. Creating a sealed Titanium unit, capable of operation on the extreme environment of Titan’s surface was a major engineering challenge. The laser successfully demonstrated its ability to meet all operational requirements in terms of pulse energy, beam pointing on target and repeatability even after extensive environmental testing.