- 900 Space Flames: Testing for the Advanced Combustion via Microgravity Experiments (ACME, https://www1.grc.nasa.gov/go/acme) project is underway on the International Space Station. In the past 2.25 years, over 900 flames have been ignited for the CLD Flame, E-FIELD Flames, BRE, Flame Design, and s-Flame experiments. For updates, photos, etc. see www.facebook.com/space.flames and www.flickr.com/photos/space-flames. For student activities and educator resources, see https://tinyurl.com/space-flames.
- Space Flames: Testing for the Advanced Combustion via Microgravity Experiments (ACME, https://go.nasa.gov/2rEeHyY) project is underway on the International Space Station. As of 15 Nov. 2019, a total of 511 flames were ignited for the CLD Flame and E-FIELD Flames experiments, where testing will next shift to the BRE investigation. For updates, photos, etc. see www.facebook.com/space.flames and www.flickr.com/photos/space-flames. For student activities and educator resources, see https://tinyurl.com/space-flames.
- 500 Space Flames: As of Nov. 8, 500 flames were ignited on the space station as part of the ACME project, where ACME’s first ‘space’ flames were ignited on Nov. 15, 2017. The tests in the past year were conducted for the Coflow Laminar Diffusion Flame (CLD Flame) and Electric-Field Effects on Laminar Diffusion Flames (E-FIELD Flames) investigations. Preliminary results from both experiments were presented on Nov. 2 at the annual meeting of the American Society for Gravitational and Space Research (ASGSR). Sample flame images from both experiments can be seen at flickr.com/photos/space-flames/albums/72157697888224630.
- Training to Burn: Rich Axelbaum (Washington U. in St. Louis) and Peter Sunderland (U. Maryland) visited NASA Glenn on Nov. 13 to prepare for ACME’s (1) Flame Design and (2) Cool Flames Investigation with Gases (CFIG) experiments. Flame Design tests should begin in the spring of 2019, while CFIG testing is planned for 2020. Phillip Irace, a doctoral student of Axelbaum, also came and stayed until Nov. 15 to see on-orbit ACME operations and participate in software testing with ground copies of the spaceflight hardware.
- E-FIELD Flames Testing Completed: The planned tests for the Electric-Field Effects on Laminar Diffusion Flames (E-FIELD Flames) experiment, led by Prof. Derek Dunn-Rankin (U. of California, Irvine), were completed on Nov. 15. They were conducted with a coflow burner and then a simple gas-jet burner, respectively in March-May and Sept.-Nov. 2018. The Burning Rate Emulator (BRE) experiment will be the next ACME investigation to be conducted.
- Career Up in Flames: On Nov. 16, Dennis Stocker (NASA Glenn) participated in a career day at the Braden Middle School in Ashtabula, OH. He gave five class-long presentations to 8th-grade students about his work on the microgravity studies of flames, focusing especially on the ACME project – for which Stocker serves as the Project Scientist. For ACME-related student activities and educator resources, see https://tinyurl.com/space-flames.
- Additional Hardware Launched: On Nov. 17, spare hardware for the Combustion Integrated Rack (CIR) – in which the ACME experiments are conducted – was successfully launched on the Northrop Grumman NG-10 cargo mission (formerly known as Orbital ATK OA-10). That notably included an intensified camera (for imaging dim flames), an Imaging and Processing Storage Unit (IPSU), and additional hard drives. On Dec. 5, three additional ACME burners and a set of hot-wire igniters were launched on the SpaceX CRS-16 mission. Both cargo launches were part of NASA’s Commercial Resupply Services (CRS) program.
Flames Aloft: During the week of September 17, 2018, space station operations for the Advanced Combustion via Microgravity Experiments (ACME) project shifted from one experiment to another. The second round of the Coflow Laminar Diffusion Flame experiment, led by Prof. Marshall B. Long (Yale University), was completed, where 162 ethylene flames were ignited during the past 4 months. The crew then began reconfiguring the experimental hardware for the second round of the Electric-Field Effects on Laminar Diffusion Flames led by Prof. Derek Dunn-Rankin (University of California, Irvine). Thus far, over 400 flames with gaseous fuels have been ignited within the Combustion Integrated Rack as part of the ACME project.
- The majority of ACME’s spaceflight hardware was delivered to the International Space Station (ISS) on the CRS-11 SpaceX Commercial Resupply mission, which launched on 3 June 2017 and arrived two days later.
- Astronauts Randy Bresnik (NASA) and Paolo Nespoli (ESA), who both trained to set up the ACME hardware, launched and arrived at the ISS on 28 July 2017 with their crew mate Sergey Ryazanskiy (RSA).
- With selection by the National Science Foundation (NSF) and the Center for the Advancement of Science in Space (CASIS), a sixth experiment was added to the ACME project. The research is on “Spherical cool diffusion flames burning gaseous fuels” and it will be led by Prof. Peter Sunderland (University of Maryland). The two Co-Investigators are Prof. Richard Axelbaum (Washington University in St. Louis) and Prof. Forman Williams (UC San Diego). For more information about the selection, read the NSF news release, Gravity’s grip on heat and fire to be studied in space.
- Additional hardware required for ACME set-up launched on SpaceX’s CRS-12 mission on 14 August 2017 and arrived two days later.
- Cosmonaut Alexander Misurkin (RSA) and astronaut Mark Vande Hei (NASA), who both trained on ACME, are expected to launch in mid-September with their crew mate Joe Acaba (NASA).
- The droplet combustion research which has long been conducted in the ISS’ Combustion Integrated Rack (CIR) will end in mid-September. The CIR will be reconfigured for ACME during late September and October, where that period will include installation and check-out of the hardware being used for the ACME experiments.
- ACME testing is expected to begin with the Coflow Laminar Diffusion Flame (CLD Flame) experiment by November 2017.
- Additional gas bottles and hardware for ACME are respectively expected to launch in November 2017 on Orbital ATK’s OA-8 mission and SpaceX’s CRS-13 mission.
- The first of ACME’s gas bottles were delivered to the International Space Station (ISS) in Oct. 2016 on Orbital ATK’s OA-5 Space Station Cargo Resupply mission. Gases are required to fill the combustion chamber, fuel the burners, and operate the gas chromatograph.
- The majority of ACME’s spaceflight hardware has shipped from Cleveland, OH for launch to the space station, following executive pre-ship reviews held in Dec. 2016 and Jan. 2017.
- The spaceflight hardware will launch in the spring and summer of 2017 on SpaceX Commercial Resupply missions CRS-11 and CRS-12.
- ACME testing is currently expected to begin on the space station in the fall of 2017 with the Coflow Laminar Diffusion Flame (CLD Flame) experiment following general ACME check-out and calibration testing.
- The Combustion Integrated Rack (CIR), in which the ACME research will be conducted, is currently being used for the Cool Flames Investigation (CFI).
- Assembly of the core elements of the spaceflight hardware – including the chamber insert, digital color camera, and avionics package – is nominally complete.
- The spaceflight hardware has undergone a variety of environmental testing, such as thermal and vibration testing. It has undergone system level check-out testing, and has also been tested for leaks, off-gassing, electromagnetic interference (EMI), and more.
- A human factors review of the spaceflight hardware was conducted in early May using the ground copy of the Combustion Integrated Rack (CIR). That ground hardware will soon be used for end-to-end testing of the spaceflight hardware.
- The third and final flight safety review was held for ACME in late May.
- A Systems Acceptance Review (SAR) will be held this summer for the core hardware, after which it will go into storage in preparation for spaceflight. Another SAR review will be held in several months, where that latter review will address most of the ACME burners as well as various back-up components.
- The coflow and BRE burners were characterized in normal-gravity by the research teams at Yale University and the University of Maryland, respectively. The coflow burner is being modified to improve the symmetry of the coflow and will afterward be returned to Yale for new characterization. This characterization is critical for the analysis of the experimental results, e.g., via computational modeling. Researchers must have a good understanding of the test conditions in order to interpret and understand the results.
- Copies of three of the spaceflight burners have been tested in the 2.2 Second Drop Tower to verify that they produce axisymmetric flames. Tests with the other spaceflight burners are planned.
- Protocols establishing partnerships between the U.S. and Russian researchers are being drafted for each experiment.
- A description of ACME can now be found in the ISS Researchers Guide to Combustion Science.
- Assembly of the spaceflight hardware is underway. Verifications will be conducted in early 2016 in preparation for launch availability in mid-2016. Ground control software is also now under development.
- The training hardware is nearly complete and crew training should begin in early 2016.
- Undergraduate engineering student Jeremy Simoes (Stevens Institute of Technology) is contributing to the project as a fall intern by conducting drop tests to evaluate the performance of spherical burners, radiometer signal strengths in microgravity, and photography with various optical filters. From September to November, a total of 56 drops were conducted in the 2.2 Second Drop Tower.
- In September and October, 8 drop tests were conducted in the Zero Gravity Research Facility to evaluate the performance of a prototype 50-mm BRE burner and the microgravity behavior of the flames under a variety of test conditions. A special focus of the final tests was to assess the magnitude of the thermal radiation under microgravity conditions.
- Arrangements are being made for the participation of Russian researchers on each of the ACME experiments.
- Five presentations and one poster from the ACME project were presented at the 2015 annual meeting of the American Society for Gravitational and Space Research (ASGSR).August 2015
- In recent months, the engineering hardware has undergone a variety of testing, e.g., vibration to test for workmanship, and review, e.g., for human factors. The assembly of the training hardware is nearly complete, and the spaceflight hardware is under construction.
- Testing for Electromagnetic Interference (EMI) revealed excessive radiated levels, where this was an anticipated risk given the high-voltage electric field required for the E-FIELD Flames experiment. A concept has been developed to mitigate this issue; it features the replacement of the bipolar power supply with a crew-exchangeable pair of mono-polar power supplies, thereby limiting tests to fields of a single polarity. EMI testing of the revised design is underway, where the initial results are promising.
- In the first half of 2015, 27 drops were conducted in the Zero Gravity Research Facility to evaluate the performance of a prototype 50-mm BRE burner and the microgravity behavior of the flames under a variety of test conditions.
- In early 2015, dozens of prototype spherical burners were evaluated in 78 tests conducted in the 2.2 Second Drop Tower to determine how well they would produce spherical microgravity flames. Based on the results, the decision was made to use 0.25-inch-diameter burners fabricated by Mott Corp. for the Flame Design and s-Flame experiments. The porous burners are made from sintered stainless steel.
- Undergraduate engineering student Angel Rodriquez (U. Washington) is contributing to the project as a summer intern by conducting 2.2-second drop tests and analyzing experimental data.
- Nine papers and 1 poster from the ACME project were presented at the9thU.S. National Combustion Meetingheld in Cincinnati, OH in May 2015. ACME plans were further described at this meeting as part of an exhibit on the Combustion Integrated Rack (CIR) research. Furthermore, astronaut Don Pettit, who conducted an ACME precursor, SLICE, on the space station in 2012, was the meeting’s banquet speaker.
An ACME fact sheet has been created.
January 2015 – ACME’s Phase II Safety Review was held in Houston on Oct. 7-8, 2014.
The ACME engineering hardware was assembled and recently underwent preliminary integrated testing with the Ground Integration Unit (GIU) for the Combustion Integrated Rack (CIR). The engineering hardware is now set up for testing in NASA Glenn’s Electromagnetic Interference Laboratory (i.e., for EMI).
Nearly 60 prototype spherical burners were fabricated for the Flame Design and s-Flame experiments, including 22 bronze burners from GKN Sinter Metals Filters GmbH, 8 stainless steel burners from Mott Corp., and 27 bronze burners from Princeton University. Evaluation testing has begun in NASA Glenn’s 2.2 Second Drop Tower to determine if they will produce microgravity flames that are sufficiently spherical.
Evaluation testing of a 25-mm diameter prototype BRE burner was completed, where a total of 35 drops were conducted in NASA Glenn’s Zero Gravity Research Facility (from Feb.-Nov. 2014). Similar evaluation has now begun a 50-mm BRE burner.
Six presentations were given by ACME researchers at the 2014 meeting of the American Society of Gravitational and Space Research (ASGSR). One of the six, “Implementation of High Dynamic Range (HDR) Image Algorithms for Improved Microgravity Flame Diagnostics” by David Giassi (Yale University) et al., was also presented as a student poster and received honorable mention recognition.
The initial results of the CLD Flame precursor experiment, Structure & Liftoff In Combustion Experiment (SLICE) have now been published. The papers were both presented at the 35th International Symposium on Combustion (San Francisco, CA; 3-8 August, 2014), where preliminary versions had been presented at the 8th U.S. National Combustion Meeting (Park City, UT; 19-22 May, 2013).
Bin Ma, Su Cao, Davide Giassi, Dennis P. Stocker, Fumiaki Takahashi, Beth Anne V. Bennett, Mitchell D. Smooke, and Marshall B. Long, “An experimental and computational study of soot formation in a coflow jet flame under microgravity and normal gravity,” Proceedings of the Combustion Institute, Volume 35, Issue 1, 2015, Pages 839–846.
S. Cao, B. Ma, B.A.V. Bennett, D. Giassi, D.P. Stocker, F. Takahashi, M.B. Long, and M.D. Smooke, “A computational and experimental study of coflow laminar methane/air diffusion flames: Effects of fuel dilution, inlet velocity, and gravity,” Proceedings of the Combustion Institute, Volume 35, Issue 1, 2015, Pages 897–903.
Left: Spherical flame from just before impact in a drop test in the 2.2 Second Drop Tower, where the dim flame image was brightened in post processing. In this test, a mixture of 30/70 ethylene/nitrogen (on a volume basis) flowed from the 6.35-mm diameter spherical burner into ambient air at atmospheric pressure. The bright glow is the hot-wire igniter which was deactivated but not retracted during the drop.
Right: BRE flame from near the end of a drop test in the Zero Gravity Research Facility. In this test, a mixture of 50/50 ethylene/nitrogen (on a volume basis) flowed from the 25-mm diameter burner into a 26/74 oxygen/nitrogen atmosphere at 0.8 atm. With this atmosphere, the normal oxygen partial pressure (i.e., 0.21 atm) has been maintained.
Finally, an updated list of ACME Publications and Presentations is now available online.
July 2014 – Two papers (listed below) on the ACME precursor experiment, Structure & Liftoff In Combustion Experiment (SLICE), will be presented at this summer’s 35th International Symposium on Combustion.
B. Ma, S. Cao, D. Giassi, D.P. Stocker, F. Takahashi, B.A.V. Bennett, M.D. Smooke, and M.B. Long, “An experimental and computational study on soot formation in a coflow jet flame under microgravity and normal gravity,” to be presented, 35th International Symposium on Combustion, San Francisco, CA, 3-8 August, 2014.
S. Cao, B. Ma, B.A.V. Bennett, D. Giassi, D.P. Stocker, F. Takahashi, M.B. Long, and M.D. Smooke, “A computational and experimental study of coflow laminar methane/air diffusion flames: Effects of fuel dilution, inlet velocity, and gravity,” to be presented, 35th International Symposium on Combustion, San Francisco, CA, 3-8 August, 2014.
SLICE was conducted on the International Space Station in early 2012 to prepare for ACME’s Coflow Laminar Diffusion Flame (CLD Flame) experiment. CLD Flame is led by Yale professors Marshall Long and Mitch Smooke, whose combined experimental and computational research (including SLICE) is described in the 2012 Yale Engineering magazine’s cover story. Two ACME posters will also be presented at the symposium:
D.P. Stocker, F. Takahashi, J.M. Hickman, and A.C. Suttles, “Advanced Combustion via Microgravity Experiments: Planned International Space Station Research on Gaseous Flames,” Work-in-Progress Poster to be presented, 35th International Symposium on Combustion, San Francisco, CA, 3-8 August, 2014.
Y. Zhang, M. Kim, P.B. Sunderland, J.G. Quintiere, J. De Ris, D.P. Stocker, F. Takahashi, P.V. Ferkul, “Burning Rate Emulator for Microgravity Studies,” Work-in-Progress Poster to be presented, 35th International Symposium on Combustion, San Francisco, CA, 3-8 August, 2014.
Finally, an updated list of ACME Publications and Presentations is now available online.
June 2014 – Undergraduate student Laurel Paxton received the Morgan McKinzie Prize for the best senior thesis from Princeton’s Department of Mechanical and Aerospace Engineering. The thesis research, “Weakly buoyant spherical diffusion flames: properties of hydrogen-CO/ethylene flames,” is in support of the Structure and Response of Spherical Diffusion Flames (s-Flame) experiment which will be conducted on the International Space Station as part of the Advanced Combustion via Microgravity Experiments (ACME) project. Her advisor, Prof. C.K. Law, is the s-Flame Principal Investigator.
April 2014 – Since Feb. 2013, over 30 tests have been conducted for the ACME project in the Zero Gravity Research Facility at the NASA Glenn Research Center (GRC). During this same period, over 200 ACME tests were conducted in NASA Glenn’s 2.2 Second Drop Tower, where much of that testing was carried out by NASA interns who were either undergraduate students or recent graduates. The drop tests were primarily conducted to evaluate (1) prototype burners fabricated by U. Maryland, Princeton U., and Yale U.; and (2) signal levels with flight-like instrumentation and cameras, e.g., in order to determine appropriate amplification and settings. The Requirements Definition Review (RDR) for the Burning Rate Emulator (BRE) experiment was held in June 2013, for which its Science Requirements Document (SRD) was updated. The BRE RDR was accompanied (on the next day) by a delta Preliminary Design Review (PDR) for ACME. In this regard, BRE was a late addition to ACME, where ACME’s RDR and PDR had been previously held (i.e., for the four initial experiments) in 2010 and 2011, respectively. The requirement changes from BRE’s RDR were fully incorporated into ACME’s Integrated Science Requirements Document (ISRD) in preparation for ACME’s Critical Design Review (CDR), which was held in November 2013. At this time, it is projected that ACME will operate on the International Space Station (ISS) from 2016 to 2019. Overviews of the ACME project were presented at the meetings of the American Society for Gravitational and Space Research (ASGSR) and the Central States Section of The Combustion Institute (CSS/CI) in November 2013 and March 2014, respectively. The paper and presentation for the latter conference are now available online.
Feb. 2013 – Preparations are underway to conduct evaluation tests for the Burning Rate Emulator (BRE) experiment in NASA Glenn’s Zero Gravity Research Facility using a prototype burner developed by the University of Maryland investigators, Profs. Jim Quintiere and Peter Sunderland. This follows forty exploratory tests that were conducted with a similar gas-fueled burner in November 2012 in NASA Glenn’s 2.2 Second Drop Tower. In each drop facility, apparent weightlessness is momentarily achieved by letting the self-contained experiment freely fall down a vertical shaft. The November tests were conducted in ambient air and sometimes revealed lifting phenomena and possible tip quenching when the fuel was methane or diluted methane. Meanwhile, the ethylene flames remained robust throughout the 2.2-second test duration. The “cup” burner used in the November tests was equipped with a heater, where its use had a significant effect on the ethylene flame as can be seen in the sample images below.
October 2012 – Detailed design is underway, where ACME passed an interim design review in June. A successful Science Concept Review was held for the Burning Rate Emulator (BRE) experiment in August, where the external reviewers concluded that BRE “may offer critical guidance in flammability assessment in space vehicles.” The Requirements Definition Review for BRE and the Critical Design Review for ACME are planned for June and November 2013, respectively. The extra reviews are necessary for BRE because it wasn’t originally an ACME experiment and its design isn’t yet fully specified. It is currently expected that ACME will begin testing on ISS in 2016.
April 2012 – Tests were recently completed on the International Space Station for the Structure & Liftoff In Combustion Experiment (SLICE) which is a precursor to ACME’s Coflow Laminar Diffusion Flame (CLD Flame) experiment. The SLICE results will enable refinement of the CLD Flame test matrix and operating procedures so as to maximize its scientific outcome. You can learn more about SLICE at its Facebook page.
January 2012 – A fifth experiment was added to the ACME project, Burning Rate Emulator (BRE), where the investigators are Profs. J.G. Quintiere and P.B. Sunderland of the University of Maryland. BRE’s objective is to improve our fundamental understanding of materials flammability and assess the relevance of existing flammability test methods for low and partial-gravity environments. The burning of solid and liquid fuels will be simulated using a flat porous burner, where the flow rate of gaseous fuel will be controlled based on the thermal feedback to the burner.
January 2011 – The Advanced Combustion via Microgravity Experiments (ACME) Preliminary Design Review (PDR) was held on January 28, 2011. The Project team demonstrated that the preliminary design meets all system requirements with acceptable risk and within cost and schedule constraints. The review board has recommended that the project proceed with detailed design.
May 2010– The Advanced Combustion via Microgravity Experiments (ACME) Requirements Definition Review (RDR) was held for two days, May 10-11, 2010 The Science Requirements Document (SRD) was signed by all parties except for one PI who had to leave early before the signature page was prepared.
August 2009 – The ACME project is conducting drop tower testing at the Glenn Research Center’s 2.2 second drop tower with the ACME E-Fields rig. The drop tower tests are focusing on the high voltage field effects on flames, these tests were conducted during the month of July 2009 by the project scientist and summer intern.