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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1996

Analysis of Apollo 8 Photography and Visual Observations

Apollo 8 was launched from Cape Kennedy, Fla., at 7 :50 a.m., e.s.t., on December 21, 1968. Two hours 50 minutes later, translunar injection was performed; and astronauts Col. Frank Borman, the commander; Capt. James A. Lovell, Jr., the command module pilot; and Maj. (now Lt. Col.) William A. Anders, the lunar module pilot, were on their way to the Moon. The spacecraft was placed in an elliptical lunar orbit at 69 hours 8 minutes after liftoff. After flying two elliptical orbits of 168.5 by 60 nautical miles with an inclination of 12° to the Equator, the spacecraft was placed in a nearly circular orbit of 59.7 by 60.7 nautical miles, in which it remained for eight orbits. At 89 hours 19 minutes, trans earth injection was performed from behind the Moon. A nearly flawless mission was completed on the morning of December 27 when splashdown occurred in the Pacific Ocean after a total elapsed time of 147 hours. Lt. Gen. Sam C. Phillips, the Director of the Apollo Program, announced that such a mission was being considered at a press conference on August 19, 1968. Formal announcement that NASA was preparing Apollo 8 for an orbital flight around the Moon was released to the press on November 12, 1968. The primary purpose of this mission was to further progress toward the goal of landing men on the Moon by gaining operational experience and testing the Apolio systems. However, a great effort was also made to accomplish worthwhile scientific tasks with photography and visual observations by the astronauts. In planning the scientific tasks to be attempted on this mission, it was obvious that one of the prime tasks should be photography of the lunar surface. Such photography would furnish valuable information on the following : 1. Approach topography and landmarks for the early Apollo landings 2. The scientific merit and the roughness of areas for possible follow-on Apollo landings 3. The broad structure and characteristics of the lunar surface During the orbital part of the mission, a major portion of the lunar far side would be in sunlight. Although almost all of the far side of the Moon has been photographed by the automated Lunar Orbiter spacecraft, the photography generally was made with the spacecraft relatively far from the Moon, limiting the Lunar Orbiter photographs to an average resolution of approximately 100 meters. Thus, Apollo photographs of the far side would have much better resolution than existing pictures. Finally, it was recognized that contamination, both as it relates to window fogging (which did occur) and to contamination clouds around t he spacecraft, should be studied for both scientific and operational interests.

Richard J. Allenby↗
NASA NTRS2020

InSight Robotic Arm Testing Activities for HP3 Mole Anomaly Recovery on Mars

The InSight lander’s Heat Flow and Physical Properties Package (HP3) was deployed on Mars in February 2019and began attempting to penetrate to its target depth range of3-5 meters shortly thereafter. However, the mole’s downwardprogress stopped after only 35 cm of penetration. In response,the project convened an Anomaly Response Team (ART) andsince then has been attempting to diagnose the problem andassist the mole using the tools available on Mars. The key assetused in this effort has been the Instrument Deployment System(IDS), which includes two cameras and a robotic InstrumentDeployment Arm (IDA). Since the IDS was originally intendedonly to deploy InSight’s primary instruments to the Martiansurface, new testbed setups, experiments, and operational protocols (e.g., command sequences) were required and had to bedeveloped on a short timeline. The HP3 Mole ART first focusedon gathering all observable data on Mars about the state ofthe mole and Support Structure Assembly (SSA), as well asthe physical properties of the Martian regolith. This includedusing the robotic arm to point the IDC at the SSA duringdiagnostic hammering attempts to observe motion of the SSAand science tether. Images taken during these attempts revealedsome motion of the SSA, but no apparent change in mole depth.At JPL, the IDS and Testbed teams re-created the hardwareconfiguration on Mars based on limited knowledge of the mole’sstate. They devised and tested techniques to use the roboticarm and cameras to accomplish previously untested activitieson Mars, including imaging the HP3, using the IDA to interactwith the terrain, and using the IDA to move the SSA awayfrom the partially-embedded mole. The team executed the morepromising techniques on Mars. After diagnostic hammering onMars, the team decided to move the SSA to gain visibility ofthe mole’s configuration and access to the soil around the mole.After developing the technique and practicing the maneuver inthe InSight testbed, the team lifted the SSA on Mars and placedit behind the mole. This revealed a pit surrounding the nowexposed mole, observations of which provided essential cluesfor determining the root cause of the mole’s lack of progress.The IDS and Testbed teams altered the testbed to match thesituation on Mars. They devised IDA techniques to determinethe Martian soil properties and assist the mole’s descent. Theytested these techniques in the testbed and executed the more978-1-7281-2734-7/20/$31.00 c 2021 IEEE. Copyright 2020 CaliforniaInstitute of Technology. U.S. Government sponsorship acknowledged.promising ones on Mars. These include using the robotic arm toalter the regolith near the mole and to push on the mole while ithammers. This paper discusses the anomaly resolution testing inthe testbed at JPL, describes how the IDS team prepared for theanomaly recovery activities on Mars, and provides preliminaryresults of the efforts to assist the HP3 mole on Mars.

Kim, Junggon↗
NASA NTRS2021

InSight Robotic Arm Testing Activities for HP3 Mole Anomaly Recovery on Mars

The InSight lander’s Heat Flow and Physical Properties Package (HP3 ) was deployed on Mars in February 2019 and began attempting to penetrate to its target depth range of 3-5 meters shortly thereafter. However, the mole’s downward progress stopped after only 35 cm of penetration. In response, the project convened an Anomaly Response Team (ART) and since then has been attempting to diagnose the problem and assist the mole using the tools available on Mars. The key asset used in this effort has been the Instrument Deployment System (IDS), which includes two cameras and a robotic Instrument Deployment Arm (IDA). Since the IDS was originally intended only to deploy InSight’s primary instruments to the Martian surface, new testbed setups, experiments, and operational protocols (e.g., command sequences) were required and had to be developed on a short timeline. The HP3 Mole ART first focused on gathering all observable data on Mars about the state of the mole and Support Structure Assembly (SSA), as well as the physical properties of the Martian regolith. This included using the robotic arm to point the IDC (Instrument Deployment Camera) at the SSA during diagnostic hammering attempts to observe motion of the SSA and science tether. Images taken during these attempts revealed some motion of the SSA, but no apparent change in mole depth. At JPL, the IDS and Testbed teams re-created the hardware configuration on Mars based on limited knowledge of the mole’s state. They devised and tested techniques to use the robotic arm and cameras to accomplish previously untested activities on Mars, including imaging the HP3 , using the IDA to interact with the terrain, and using the IDA to move the SSA away from the partially-embedded mole. The team executed the more promising techniques on Mars. After diagnostic hammering on Mars, the team decided to move the SSA to gain visibility of the mole’s configuration and access to the soil around the mole. After developing the technique and practicing the maneuver in the InSight testbed, the team lifted the SSA on Mars and placed it behind the mole. This revealed a pit surrounding the now exposed mole, observations of which provided essential clues for determining the root cause of the mole’s lack of progress. The IDS and Testbed teams altered the testbed to match the situation on Mars. They devised IDA techniques to determine the Martian soil properties and assist the mole’s descent. They tested these techniques in the testbed and executed the more promising ones on Mars. These include using the robotic arm to alter the regolith near the mole and to push on the mole while it hammers. This paper discusses the anomaly resolution testing in the testbed at JPL, describes how the IDS team prepared for the anomaly recovery activities on Mars, and provides preliminary results of the efforts to assist the HP3 mole on Mars.

Kim, Junggon↗
NASA NTRS2004

Fresnel Lenses for Wide-Aperture Optical Receivers

Wide-aperture receivers for freespace optical communication systems would utilize Fresnel lenses instead of conventional telescope lenses, according to a proposal. Fresnel lenses weigh and cost much less than conventional lenses having equal aperture widths. Plastic Fresnel lenses are commercially available in diameters up to 5 m large enough to satisfy requirements for aperture widths of the order of meters for collecting sufficient light in typical long-distance free-space optical communication systems. Fresnel lenses are not yet suitable for high-quality diffraction-limited imaging, especially in polychromatic light. However, optical communication systems utilize monochromatic light, and there is no requirement for high-quality imaging; instead, the basic requirement for an optical receiver is to collect the incoming monochromatic light over a wide aperture and concentrate the light onto a photodetector. Because of lens aberrations and diffraction, the light passing through any lens is focused to a blur circle rather than to a point. Calculations for some representative cases of wide-aperture non-diffraction-limited Fresnel lenses have shown that it should be possible to attain blur-circle diameters of less than 2 mm. Preferably, the blur-circle diameter should match the width of the photodetector. For most high-bandwidth communication applications, the required photodetector diameters would be about 1 mm. In a less-preferable case in which the blur circle was wider than a single photodetector, it would be possible to occupy the blur circle with an array of photodetectors. As an alternative to using a single large Fresnel lens, one could use an array of somewhat smaller lenses to synthesize the equivalent aperture area. Such a configuration might be preferable in a case in which a single Fresnel lens of the requisite large size would be impractical to manufacture, and the blur circle could not be made small enough. For example one could construct a square array of four 5-m-diameter Fresnel lenses to obtain the same light-collecting area as that of a single 10-m-diameter lens. In that case (see figure), the light collected by each Fresnel lens could be collimated, the collimated beams from the four Fresnel lenses could be reflected onto a common offaxis paraboloidal reflector, and the paraboloidal reflector would focus the four beams onto a single photodetector. Alternatively, detected signal from each detector behind each lens would be digitized before summing the signals.

Hemmati, Hamid↗