GRCop-42 Development and Hot-Fire Testing Using Additive Manufacturing Powder Bed Fusion for Channel-Cooled Combustion Chambers
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The Moon is again in reach. NASA and its commercial and international partners are on the way back. The team is working to land the first woman and the first person of color on the planetary body. NASA and its partners made significant progress towards that goal in the latter half of 2020 and the first half of 2021, including on the agency’s Space Launch System (SLS) rocket – a key part of the Artemis program. The SLS core stage for the Artemis I mission – the first launch of SLS and an uncrewed Orion capsule – completed the Green Run test series and was successfully mated with the SLS twin solid rocket boosters on the mobile launcher at Kennedy Space Center (KSC). All of the major systems for Artemis I are at KSC for assembly, integration, and launch, targeted for late 2021. Work also continued on SLS hardware for Artemis II, which will be the first flight of crew on Orion and SLS. Work progressed on core stage components, booster segments, and other hardware for Artemis III and future missions. This paper will detail the progress made.
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NASA and its commercial and international partners are on the way back to the Moon. Significant progress towards that goal was made in 2021, including on the agency’s Space Launch System (SLS) rocket – a key part of the Artemis initiative. The SLS core stage for the Artemis I mission – the first launch of SLS and an uncrewed Orion capsule – completed its Green Run test series in early 2021 and was successfully mated with the SLS twin solid rocket boosters on the mobile launcher at Kennedy Space Center (KSC). The launch vehicle stage adapter, interim cryogenic propulsion stage, and the Orion stage adapter structural test article and Orion spacecraft mass simulator were also stacked. The flight Orion spacecraft and Orion stage adapter are being prepared for stacking and launch, targeted for late 2021 following a wet dress rehearsal at Launch Complex 39B. SLS hardware for Artemis II, which will be the first flight of crew on Orion and SLS, is also in work. Work progressed on core stage components, booster segments, and other hardware for Artemis III and future missions. This paper will detail the progress made.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
An experimental study was initiated that included the long-term testing of the following SOFI materials, which make up the majority of the Thermal Protection System of the Shuttle External Tank: NCFI 24-124 (acreage foam) and BX-265 (close-out foam, including the intertank flange and bipod areas). A potential alternate material, NCFI 27-68 (acreage foam with flame retardant removed), was also tested. Fire chemistry testing was completed on samples that were retrieved after aging/weathering at intervals of 3, 6, and 12 months. The testing included three standard test methods: limiting oxygen index (ASTM G125), radiant panel (ASTM E162), and cone calorimeter (ASTM E1354).
The Space Shuttle vehicle (SSV) is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers (BC) are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the SSV and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the BC for two specific reasons; 1. to eliminate lead for environmental concerns, and 2. to reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hangups. This upgrade will replace the lead liner with an aluminum foam material. The aluminum foam used as a energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: A. Lead handling/ exposure, and possible contamination, along with hazardous waste disposal will be eliminated; B. Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam over lead; C. The new aluminum liner is designed to catch all shrapnel from frangible nuts thus virtually eliminating chance of foreign object debris (FOD) exiting the HDP, and causing potential damage to the vehicle; D. Potential of using the lighter aluminum liner over lead, allows for easier assembly and disassembly of blast container elements, also allowing for improvements in safety, operator handling, and efficiency of operations. Six BC firing tests will be required to determine if the new liner material will perform in a way to decrease the chance of stud hangups and enhance the ability of the BC to retain blast debris. Testing will be performed at the Kennedy Space Center (KSC) facility known as the Launch Equipment Test Facility (LETF), and will simulate the SRB hold- down post, with actual BC hardware and pyrotechnics assembled, and then test fired. Initial testing was performed in 1997 using a frangible nut in a static drop test over lead and aluminum foam sheet materials. The aluminum foam showed a dramatic improvement of energy absorption over the lead liner material. Proof-of-Principle testing at the KSC-LETF commenced in May, 1998, and is expected to be completed by June, 1998.
Various refractory coating systems were evaluated for rocket nozzle applications by actual rocket test firings. A reference is noted which identifies failure mechanisms and gives results of the firing tests for 18 coating systems. Iridium, iridium-rhenium, and hafnium oxide-zirconium oxide coatings show most promising results.
The national weapons design laboratories (Los Alamos National Laboratory and Lawrence Livermore National Laboratory) test fire nuclear devices at the Nevada Test Site (NTS), which is spread over an area of over 1200 square miles (a bit larger than the state of Rhode island). On each test there are hundreds of high time resolution recordings made of nuclear output waveforms and other phenomena. In order to synchronize these recordings with each other, with the nuclear device, and with offsite recordings, there is a requirement that the permanent command center and the outlying temporary firing sites be time tied to each other and to UTC to permit firing the shot at a predetermined time with an accuracy of about a microsecond. The system is so designed that this can reduce to about 100 nanoseconds if it should prove necessary in the future.
Tests of the stability of several monopropellants under the effects of impact and heat were conducted in order to assess the potential hazard in a propellant storage area from major fires and enemy attack. Hydrazine, hydrazine nitrate solution, n-propyl nitrate, and ethylene oxide were all tested in one-gallon aluminum containers (half of them filled to 25% and half to 95% capacity) by being subjected to oil bonfires and wood bonfires, and 20-mm incendiary, 20mm high explosive incendiary, and .30-caliber rifle fire. Aviation gasoline was tested in the same manner, for comparison. In the bonfire tests, all four monopropellants generally gave explosion intensities equivalent to one another regardless of the type of bonfire (oil or wood) or the amount of liquid in the test container. Occasionally, however, with hydrazine, hydrazine nitrate solution, and n-propyl nitrate, anomalous results occurred: there was either (a) no explosion or (b) an explosion of above average intensity. Ethylene oxide more nearly approximated the behavior of aviation gasoline than did the other monopropellants. In the rifle-fire tests, n-propyl nitrate appeared to be most shock- sensitive since it was exploded by all three types of ammunition. Hydrazine and hydrazine nitrate solution were exploded by the high-explosive ammunition, but not by the incendiary or .30-dber ammunition. Ethylene oxide was not exploded by any of the gunfire, but the liquid was ignited by both incendiary and high-explosive incendiary ammunition.
The concentrations of hydrocarbons in the gases from fire toxicity tests are often determined to obtain an indication of their contribution to toxic effects and of the mechanisms of thermal decomposition. Because the gas compositions produced in the University of San Francisco/NASA toxicity screening test are generated under identical pyrolysis conditions, they offer the potential of comparing the flash-fire propensity of various materials.
Protective coating systems for refractory metal used in rocket engine nozzles - rocket engine test firing
A hydrogen-oxygen subscale rocket combustion chamber was designed incorporating an advanced design concept to reduce strain and increase life. The design permits unrestrained thermal expansion of a circumferential direction and, thereby, provides structural compliance during the thermal cycling of hot-fire testing. The chamber was built and test fired at a chamber pressure of 4137 kN/sq m (600 psia) and a hydrogen-oxygen mixture ratio of 6.0. Compared with a conventional milled-channel configuration, the new structurally compliant chamber had a 134 or 287 percent increase in fatigue life, depending on the life predicted for the conventional configuration.
The paper describes an experimental program carried out to evaluate a possible method for testing the fire-containment qualities of aircraft interior panels. The experimental apparatus consisted of a burner that simulates various fire loads under different ventilation conditions in an enclosure of approximately the same size as an aircraft lavatory module. Two fire-containment tests are discussed in which two adjoining walls of the enclosure were made from state-of-the-art composite panels; rats were exposed to the combustion products in order to evaluate the toxic threat posed by those products. The results show that the burner can be employed to represent various fire-load conditions and that the methodology developed for fire containment can be useful in evaluating the fire resistance of composite panels before conducting large-scale tests. It is concluded that elements of the fire-containment criteria include the temperature rise on the backface of the panels as a function of time, the flame burn-through by either decomposition or severe distortion of the material, and the toxicity of the combustion gases evolved.