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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Ice Dusty Plasma (Final Report)

The NSF/DOE funding described in this final report was for constructing a substantial upgrade that would enable operation at variable and much lower cryogenic temperatures than was available in a previous experiment that operated from 2013 to 2019. Components for the upgraded experiment were designed and ordered from August to December 2019 and assembly began in early 2020. However, COVID-19 halted all lab work for much of 2020 and then when lab work resumed, numerous restrictions on lab access and in-lab time further impeded progress. Because of these delays, first plasma was obtained in late 2021 and a normal work pace resumed only in mid-2022. A no-cost extension was requested because the COVID-19 delays prevented work from being done at the anticipated rate. Constructing a water-ice experiment was a significant gamble because the parameter regime differs substantially from conventional laboratory plasmas and injecting water vapor into a plasma goes very much against convention as one normally goes to great lengths to avoid water vapor. This experiment opens a new frontier, namely the study of how charged ice grains form, grow, and interact with a plasma environment. The just-completed upgrade was a further gamble because it combines technology never previously used together (cryocoolers, plasma, and ice).

36 MATERIALS SCIENCE↗
NASA NTRS1985

Multiple gravity-wave breaking levels

Gravity waves for which the expression /u(bar)-c/, where u(bar) = mean flow speed and c = wave phase speed, exhibits a sharp minimum in the upper troposphere or lower stratosphere, have decaying amplitudes above this level despite their exponentially decreasing mean density; this decay then ceases and growth resumes. If a gravity wave breaks below the level of /u(bar)-c/min, it will cease breaking above this level, while resuming breaking at some higher, second level which is a lower bound for the level of breaking in the mesosphere. Explicit calculations show the second breaking levels to be close to observed levels of mesospheric gravity wave breaking.

Lindzen, R. S.↗
NASA NTRS1994

Cell cycle arrest by prostaglandin A1 at the G1/S phase interface with up-regulation of oncogenes in S-49 cyc- cells

Our previous studies have implied that prostaglandins inhibit cell growth independent of cAMP. Recent reports, however, have suggested that prostaglandin arrest of the cell cycle may be mediated through protein kinase A. In this report, in order to eliminate the role of c-AMP in prostaglandin mediated cell cycle arrest, we use the -49 lymphoma variant (cyc-) cells that lack adenylate cyclase activity. We demonstrate that dimethyl prostaglandin A1 (dmPGA1) inhibits DNA synthesis and cell growth in cyc- cells. DNA synthesis is inhibited 42% by dmPGA1 (50 microM) despite the fact that this cell line lacks cellular components needed for cAMP generation. The ability to decrease DNA synthesis depends upon the specific prostaglandin structure with the most effective form possessing the alpha, beta unsaturated ketone ring. Dimethyl PGA1 is most effective in inhibiting DNA synthesis in cyc- cells, with prostaglandins PGE1 and PGB1 being less potent inhibitors of DNA synthesis. DmPGE2 caused a significant stimulation of DNA synthesis. S-49 cyc- variant cells exposed to (30-50 microns) dmPGA1, arrested in the G1 phase of the cell cycle within 24 h. This growth arrest was reversed when the prostaglandin was removed from the cultured cells; growth resumed within hours showing that this treatment is not toxic. The S-49 cyc- cells were chosen not only for their lack of adenylate cyclase activity, but also because their cell cycle has been extensively studied and time requirements for G1, S, G2, and M phases are known. Within hours after prostaglandin removal the cells resume active DNA synthesis, and cell number doubles within 15 h suggesting rapid entry into S-phase DNA synthesis from the G1 cell cycle block.(ABSTRACT TRUNCATED AT 250 WORDS).

NASA Discipline Cell Biology↗
NASA NTRS2006

A Year in the Life of International Space Station

The past twelve months (October 2005 to September 2006) have been among the busiest in the life of the International Space Station (ISS), both in terms of on-orbit operations as well as future planning, for both ISS systems and research. The Expedition 12 and 13 crews completed their missions successfully, carrying out research for Russia, the United States, Europe and Japan, and bringing continuous ISS occupancy to nearly six years. The European Space Agency's (ESA) first Long Duration Mission on ISS is underway, involving significant international research. The Expedition 14 crew completed its training and is embarking on its own 6-month mission with a full slate of international research. Future crews are in training for their respective assembly and research missions. Shuttle flights resumed after a 10-month hiatus, delivering new research facilities and resuming assembly of ISS. ESA's Columbus research module was delivered to the Kennedy Space Center, joining Japan's Kibo research module already there. Following preflight testing, the two modules will launch in 2007 and 2008, respectively, joining Destiny as ISS's research infrastructure. A revised ISS configuration and assembly sequence were endorsed by all the Partners, with a reduced number of Shuttle flights, but for the first time including plans for post-Shuttle ISS operations after 2010. The new plan will pose significant challenges to the ISS research community. As Europe and Japan build their on-orbit research infrastructure, and long-term plans become firmer, the next 12 months should prove to be equally challenging and exciting.

Uri, John J.↗
NASA NTRS2009

Rotary Percussive Auto-Gopher for Deep Drilling and Sampling

The term "rotary percussive auto-gopher" denotes a proposed addition to a family of apparatuses, based on ultrasonic/ sonic drill corers (USDCs), that have been described in numerous previous NASA Tech Briefs articles. These apparatuses have been designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. In the case of the rotary percussive autogopher, the emphasis would be on developing an apparatus capable of penetrating to, and acquiring samples at, depths that could otherwise be reached only by use of much longer, heavier, conventional drilling-and-sampling apparatuses. To recapitulate from the prior articles about USDCs: A USDC can be characterized as a lightweight, low-power jackhammer in which a piezoelectrically driven actuator generates ultrasonic vibrations and is coupled to a tool bit through a free mass. The bouncing of the free mass between the actuator horn and the drill bit converts the actuator ultrasonic vibrations into sonic hammering of the drill bit. The combination of ultrasonic and sonic vibrations gives rise to a hammering action (and a resulting chiseling action at the tip of the tool bit) that is more effective for drilling than is the microhammering action of ultrasonic vibrations alone. The hammering and chiseling actions are so effective that the size of the axial force needed to make the tool bit advance into soil, rock, or another material of interest is much smaller than in ordinary rotary drilling, ordinary hammering, or ordinary steady pushing. The predecessor of the rotary percussive auto-gopher is an apparatus, now denoted an ultrasonic/sonic gopher and previously denoted an ultrasonic gopher, described in "Ultrasonic/ Sonic Mechanism for Drilling and Coring" (NPO-30291), NASA Tech Briefs Vol. 27, No. 9 (September 2003), page 65. The ultrasonic/sonic gopher is intended for use mainly in acquiring cores. The name of the apparatus reflects the fact that, like a gopher, it periodically stops advancing at the end of the hole to bring excavated material (in this case, a core sample) to the surface, then re-enters the hole to resume the advance of the end of the hole. By use of a cable suspended from a reel on the surface, the gopher is lifted from the hole to remove a core sample, then lowered into the hole to resume the advance and acquire the next core sample.

Bar-Cohen, Yoseph↗
NASA NTRS2009

Ares V Overview and Status

As part of NASA s Constellation Program to resume exploration beyond low Earth orbit (LEO), the Ares V heavy-lift cargo launch vehicle as currently conceived will be able to send more crew and cargo to more places on the Moon than the Apollo Program Saturn V. (Figure 1) It also has unprecedented cargo mass and volume capabilities that will be a national asset for science, commerce, and national defense applications. Compared to current systems, it will offer approximately five times the mass and volume to most orbits and locations. The Columbia space shuttle accident, the resulting investigation, the Vision for Space Exploration, and the Exploration Systems Architecture Study (ESAS) broadly shaped the Constellation architecture. Out of those events and initiatives emerged an architecture intended to replace the space shuttle, complete the International Space Station (ISS), resume a much more ambitious plan to explore the moon as a stepping stone to other destinations in the solar system. The Ares I was NASA s main priority because of the goal to retire the Shuttle. Ares V remains in a concept development phase, evolving through hundreds of configurations. The current reference design was approved during the Lunar Capabilities Concept Review/Ares V Mission Concept Review (LCCR/MCR) in June 2008. This reference concept serves as a starting point for a renewed set of design trades and detailed analysis into its interaction with the other components of the Constellation architecture and existing launch infrastructure. In 2009, the Ares V team was heavily involved in supporting the Review of U.S. Human Space Flight Plans Committee. Several alternative designs for Ares V have been supplied to the committee. This paper will discuss the origins of the Ares V design, the evolution to the current reference configuration, and the options provided to the review committee.

Creech, Steve↗
NASA NTRS2010

Current Status of NASA's Heavy Lift Plans

Numerous studies since the Apollo Program of the 1960s have highlighted the benefits of - and the need for - a national heavy lift launch capability to support human exploration, science, national security, and commercial development of space. NASA's most recent and most refined effort to develop that heavy lift capability is the Ares V. Ares V is a key element of NASA's Constellation Program. It s overall goal s part of approved national space policy is to retire the Space Shuttle and develop its successor, complete the International Space Station, and resume human exploration beyond low Earth orbit (LEO), beginning with exploration of the Moon as a step to other destinations in the Solar System. Ares V s first role is that of cargo vehicle to carry a lunar lander into Earth orbit, rendezvous with astronauts launched on the smaller Ares I crew launch vehicle, and perform the trans lunar injection (TLI) mission to send the mated crew and lander vehicles to the Moon. The design reference missions (DRMs) envisioned for it also include direct lunar cargo flights and a human Mars mission. Although NASA's priority from the start of the Constellation Program to the present has been development of the Ares I and Orion crew vehicle to replace the retiring Shuttle fleet, the Ares team has made significant progress in understanding the performance, design trades, technology needs, mission scenarios, ground and flight operations, cost, and other factors associated with heavy lift development. The current reference configuration was selected during the Lunar Capabilities Concept Review (LCCR) in fall 2008. That design has served since then as a point of departure for further refinements and trades among five participating NASA field centers. Ares V development to date has benefited from progress on the Ares I due to commonality between the vehicles. The Ares I first stage completed a successful firing of a 5-segment solid rocket motor. The Ares I-X launch Numerous studies since the Apollo Program of the 1960s have highlighted the benefits of and the need for - a national heavy lift launch capability to support human exploration, science, national security, and commercial development of space. NASA s most recent and most refined effort to develop that heavy lift capability is the Ares V. Ares V is a key element of NASA s Constellation Program. It s overall goal s part of approved national space policy is to retire the Space Shuttle and develop its successor, complete the International Space Station, and resume human exploration beyond low Earth orbit (LEO), beginning with exploration of the Moon as a step to other destinations in the Solar System. Ares V s first role is that of cargo vehicle to carry a lunar lander into Earth orbit, rendezvous with astronauts launched on the smaller Ares I crew launch vehicle, and perform the trans lunar injection (TLI) mission to send the mated crew and lander vehicles to the Moon. The design reference missions (DRMs) envisioned for it also include direct lunar cargo flights and a human Mars mission. Although NASA s priority from the start of the Constellation Program to the present has been development of the Ares I and Orion crew vehicle to replace the retiring Shuttle fleet, the Ares team has made significant progress in understanding the performance, design trades, technology needs, mission scenarios, ground and flight operations, cost, and other factors associated with heavy lift development. The current reference configuration was selected during the Lunar Capabilities Concept Review (LCCR) in fall 2008. That design has served since then as a point of departure for further refinements and trades among five participating NASA field centers. Ares V development to date has benefited from progress on the Ares I due to commonality between the vehicles. The Ares I first stage completed a successful firing of a 5-segment solid rocket motor. The Ares I-X launch successfully demonstrated in suborbital flighhe ability to assemble, prepare, launch, control and recover the Ares I configuration and compare performance to computer models. Component tests continue on the J-2X engine, which will put both the Ares I and Ares V upper stages into orbit. In addition, more than 100,000 parts have been manufactured or on the assembly line for the first J-2X powerpack and the first two development engines, with hot fire tests to begin in 2011. This paper will further detail the progress to date on the Ares V and planned activities for the remainder of 2010. In addition, the Ares V team has continued its outreach to potential user communities in science and national security. Through the Constellation Program, NASA has amassed an enormous knowledge base in the design, technologies, and operations of heavy lift launch vehicles that will be a national asset for any future launch vehicle decision. This early phase of the design presents the best opportunity to incorporate where possible the insights and needs of other users.

Creech, Steve↗
NASA NTRS2006

Educational Experiences of Embry-Riddle Students through NASA Research Collaboration

NASA's educational. programs benefit students and faculty while increasing the overall productivity of the organization. The NASA Graduate Student Research Program (GSRP) awards fellowships for graduate study leading to both masters and doctoral degrees in several technical fields. GSRP participants have the option to utilize NASA Centers andlor university research facilities. In addition, GSRP students can serve as mentors for undergrad students to provide a truly unique learning experience. NASA's Cooperative Education Program allows undergraduate students the chance to gain "real-world" work experience in the field. It also gives NASA a no risk capability to evaluate the true performance of a prospective new hire without relying solely on a "paper resume" while providing the students with a greater hiring potential upon graduation, at NASA or elsewhere. University faculty can also benefit by participating in the NASA Faculty Fellowship Program (NFFP). This program gives the faculty an opportunity to work with NASA peers. The Mission Analysis Branch of the Expendable Launch Vehicles Division at NASA Kennedy Space Center has utilized these two programs with students from Embry-Riddle Aeronautical University (ERAU) to conduct research in modeling and developing a parameter estimation method for spacecraft fuel slosh using simple pendulum analogs. Simple pendulum models are used to understand complicated spacecraft fuel slosh behavior. A robust parameter estimation process will help to identif' the parameters that will predict the response fairly accurately during the initial stages of design. These programs provide students with a unique opportunity to work on "real-world" aerospace problems, like spacecraft fuel slosh,. This in turn reinforces their problem solving abilities and their communication skills such as interviewing, resume writing, technical writing, and presentation. Faculty benefits by applying what they have learned to the classroom. Through university collaborations with NASA and industry help students to acquire skills that are vital for their success upon entering the workforce.

Schlee, Keith↗
NASA NTRS2007

Educational Experiences of Embry-Riddle Students through NASA Research Collaboration

NASA's educational programs benefit students while increasing the overall productivity of the organization. The NASA Graduate Student Research Program (GSRP) awards fellowships for graduate study leading to both masters and doctoral degrees in several technical fields, while the Cooperative Education program allows undergraduate and graduate students the chance to gain work experience in the field. The Mission Analysis Branch of the Expendable Launch Vehicles Division at NASA Kennedy Space Center has utilized these two programs with students from Embry-Riddle Aeronautical University to conduct research in modeling and developing a parameter estimation method for spacecraft fuel slosh using simple pendulum analogs. Simple pendulum models are used to understand complicated spacecraft fuel slosh behavior. A robust parameter estimation process will help to identiFy the parameters that will predict the response fairly accurately during the initial stages of design. NASA's Cooperative Education Program trains the next wave of new hires while allowing graduate and undergraduate college students to gain valuable "real-world" work experience. It gives NASA a no risk capability to evaluate the true performance of a prospective new hire without relying solely on a paper resume, while providing the students with a greater hiring potential upon graduation, at NASA or elsewhere. In addition, graduate students serve as mentors for undergrad students and provide a unique learning environment. Providing students with a unique opportunity to work on "real-world" aerospace problems ultimately reinforces their problem solving abilities and their communication skills (in terms of interviewing, resume writing, technical writing, presentation, and peer review) that are vital for the workforce to succeed.

Schlee, Keith↗
NASA NTRS2011

The Dawn of Vesta Science

The Dawn mission is part of NASA's Discovery Program and has as its goal the scientific exploration of the two most massive main-belt asteroids, Vesta and Ceres. The Dawn spacecraft was launched from the Cape Canaveral Air Force Station on September 27, 2007 on a Delta-II 7925H-9.5 (Delta-II Heavy) rocket that placed the 1218-kg spacecraft onto an Earth-escape trajectory. On-board the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide a total ?V of 11.3 km/s for the heliocentric transfer to Vesta, orbit capture at Vesta, transfer between Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer between Ceres science orbits. Fullpower thrusting from December 2007 through October 2008 was used to successfully target a Mars gravity assist flyby in February 2009 that provided an additional ?V of 2.6 km/s. Deterministic thrusting for the heliocentric transfer to Vesta resumed in June 2009 and concluded with orbit capture at Vesta on July 16, 2011. An additional 210 hours of IPS thrusting was used to enter the first Vesta science orbit, called Survey orbit, on August 3, 2011 at an altitude of approximately 2,735 km. To date the IPS has been operated for 23,621 hours, consumed approximately 252 kg of xenon, and provided a delta-V of approximately 6.7 km/s. The IPS performance characteristics are very close to the expected performance based on analysis and testing performed pre-launch. The only significant issue in over the almost four years of IPS operations in flight was the temporary failure of a valve driver board in the Digital Control and Interface Unit-1 (DCIU-1), resulting in a loss of thrust of approximately 29 hours. Thrusting operations resumed after switching to DCIU-2, and power cycling conducted after orbit capture restored DCIU-1 to full functionality. After about three weeks of Survey orbit operations the IPS will be used to transfer the spacecraft to the other planned science orbit altitudes. After approximately one year of science operations the IPS will be used for escape from Vesta and then for thrusting to Ceres with a planned arrival date at Ceres in February 2015. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through the start of science operations at Vesta.

electric propulsion↗
NASA NTRS2011

In-Flight Operation of the Dawn Ion Propulsion System Through Orbit Capture at Vesta

The Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt asteroids, Vesta and Ceres. The Dawn spacecraft was launched from Cape Canaveral Air Force Station on September 27, 2007 on a Delta -II 7925H-9.5 (Delta-II Heavy) rocket that placed the 1218 kg spacecraft into an Earth-escape trajectory. Onboard the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide most of the ?V needed for heliocentric transfer to Vesta, orbit capture at Vesta, transfer among Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer among Ceres science orbits. The first 80 days after launch were dedicated to the initial checkout of the spacecraft which was followed by about ten months of full-power thrusting leading to a Mars gravity assist in February 2009 that provided 1 km/s of heliocentric energy increase and is the only part of the mission following launch in which a needed velocity change is not accomplished by the IPS. Deterministic thrusting for heliocentric transfer to Vesta resumed in June 2009 and was concluded with orbit capture at Vesta in July 2011. IPS was operated for approximately 23,400 hours, consumed approximately 250 kg of xenon, and provided a delta-V of approximately 6.7 km/s to achieve orbit capture at Vesta. IPS performance characteristics are very close to the expected performance characteristics based on analysis performed pre-launch. The only significant problem to have occurred over the almost four years of IPS operations in flight was the temporary failure of a valve driver board in DCIU-1, resulting in a loss of thrust of approximately 29 hours. Thrusting operations resumed after switching to DCIU-2, and power cycling conducted after orbit capture indicates DCIU-1 is completely operational. After about three weeks of survey operations IPS will be used to maneuver the spacecraft as needed for science operations including orbit transfers. After approximately one year of science operations IPS will then be used for escape from Vesta and begin thrusting for cruise to Ceres with a planned arrival date at Ceres in February 2015. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through orbit capture and the start of science operations at Vesta.

Garner, Charles E.↗
NASA NTRS2016

In the Hot Seat: STS-115 Lightning Strike Stand Down Debate - NASA Case Study

There is no way the PIC's could have seen any current' was the gist of Mike Griffin's assessment. Griffin was the NASA Administrator at the time. The buck stopped at his desk. Holding a napkin out to Pat Lampton, Griffin showed Lampton the calculations he'd made over dinner that predicted that the Pyrotechnic Initiator Controllers (PIC's) at the base of the Space Shuttle Solid Rocket Boosters (SRBs) were fine. A lightning strike the day before, the worst ever experienced with a Space Shuttle on the launch pad, caused a halt to the launch count down as technicians, engineers, and managers scrambled identify any damage to the launch system. SRB technicians and engineers assessed the data against their Lightning Strike Re-Test Requirements, determining that all but one of the requirements could be checked if they resumed the countdown. For the one remaining requirement, testing the integrity of the PIC's would require 96 hours to set up, test, and reassemble. The engineers were convinced that there was no way to do calculations to show the PIC's were okay. The only option was to stand down. It was SRB Deputy Project Manager (PM) Pat Lampton's responsibility to decide what the SRB project position needed to be to certify that their hardware was safe to fly. He had to communicate that decision to the Mission Management Team (MMT) as a Go or No Go position to resume the count down. If the answer was Go they could still meet a delayed, but acceptable launch schedule. If the answer was No Go, rescheduling the launch would be a grueling shuffling of hardware, personnel, and mission timelines to accommodate Russian missions to the Space Station, supplies for the launch, and personnel manning launch operations. On top of that, Hurricane Ernesto was spinning off the coast of Florida, threatening the need for the Shuttle to roll back to the hangar if they waited too long.

Kummer, Lizette↗
NASA NTRS2015

In-Flight Operation of the Dawn Ion Propulsion System Through Survey Science Orbit at Ceres

The Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt objects, Vesta and Ceres. The Dawn spacecraft was launched from the Cape Canaveral Air Force Station on September 27, 2007 on a Delta-II 7925H- 9.5 (Delta-II Heavy) rocket that placed the 1218-kg spacecraft onto an Earth-escape trajectory. On-board the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide a total delta V of 11 km/s for the heliocentric transfer to Vesta, orbit capture at Vesta, transfer between Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer between Ceres science orbits. Full-power thrusting from December 2007 through October 2008 was used to successfully target a Mars gravity assist flyby in February 2009 that provided an additional delta V of 2.6 km/s. Deterministic thrusting for the heliocentric transfer to Vesta resumed in June 2009 and concluded with orbit capture at Vesta on July 16, 2011. From July 2011 through September 2012 the IPS was used to transfer to all the different science orbits at Vesta and to escape from Vesta orbit. Cruise for a rendezvous with Ceres began in September 2012 and concluded with the start of the approach to Ceres phase on December 26, 2015, leading to orbit capture on March 6, 2015. Deterministic thrusting continued during approach to place the spacecraft in its first science orbit, called RC3, which was achieved on April 23, 2015. Following science operations at RC3 ion thrusting was resumed for twenty-five days leading to arrival to the next science orbit, called survey orbit, on June 3, 2015. The IPS will be used for all subsequent orbit transfers and trajectory correction maneuvers until completion of the primary mission in approximately June 2016. To date the IPS has been operated for over 46,774 hours, consumed approximately 393 kg of xenon, and provided a delta V of over 10.8 km/s to the spacecraft. The IPS performance characteristics are very close to the expected performance based on analysis and testing performed pre-launch. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through arrival at the second science orbit at Ceres.

Garner, Charles E.↗
NASA NTRS2020

CloudSat - From the A-Train to the C-Train

The CloudSat satellite was launched from Vandenberg Air Force Base, in California, on April 28, 2006. It was launched with the CALIPSO satellite, a joint mission between the National Aeronautics and Space Administration (NASA) and the Centre National D'Etudes Spatiales (CNES). CloudSat and CALIPSO were designed to fly in formation with each other, to combine their complimentary scientific measurements. The two missions were maneuvered into the Earth Science Afternoon Constellation (A-Train) shortly after launch and have flown in formation together since then. Originally designed to fly for 22 months, the CloudSat satellite has far exceeded expectations. Inflight anomalies on CloudSat necessitated changes to both the daily concept of operations and formation flying operations with CALIPSO. In 2011, a severe battery anomaly restricted CloudSat science data collection and maneuverability to the sunlit portions of the orbit. In 2017, CloudSat suffered a reaction wheel failure, triggering the criteria established to exit the A-Train. CloudSat successfully exited the A-Train in early 2018, suspending formation flying and joint science observations with CALIPSO. The joint CloudSat/CALIPSO science team continued collaboration with discussions focused on resuming joint observations. As both satellites were aging and CALIPSO was nearing the exhaustion of satellite propellant, the decision was made to lower CloudSat to the CALIPSO graveyard orbit, to be joined by CALIPSO as soon as feasible. With NASA’s approval, CloudSat was maneuvered to the lower orbit over the course of several months in mid-2018. Once CloudSat was in place, and with approval from CNES, CALIPSO began the delicate dance of lowering their orbit and re-aligning the satellite ground tracks. CloudSat and CALIPSO resumed formation flying in the newly dubbed C-Train (CloudSat and CALIPSO) orbit in the Fall of 2018. The ingenuity of the CloudSat and CALIPSO teams made the concept of the C-Train a reality. This paper will discuss the decision processes and the operational challenges the CloudSat flight team faced while designing and implementing the C-Train.

Witkowski, M.M.↗
DOE OSTI2021

Recent Thermal and Hydraulic Stimulation Results at Raft River, ID EGS Site

The Raft River geothermal system, located 160 km northwest of Salt Lake City, Utah is the site of a Department of Energy Enhanced Geothermal System (EGS) stimulation demonstration project. The target well RRG-9 ST-1, is roughly 1.6 km (1 mile) south of the power plant. This well has undergone a series of thermal and hydraulic stimulation treatments. Furthermore, the well passes through approximately 1,524 m MD (5,000 ft. MD) of laterally discontinuous Quaternary and Tertiary volcanoclastic and volcanic rocks that unconformably overlie the Precambrian basement. The Elba Quartzite formation located in the Precambrian basement is the target zone for the stimulation program. Fluid injected into the well exits through a fracture zone in the Elba Quartzite at 1,567 m TVD (5,140 ft. TVD). In June 2013 low-rate stimulation began at RRG-9 ST-1 using injection water from the geothermal plant. The average injection rate, temperature, and well head pressure of the low-rate stimulation was 163 Lpm (43 gpm), 34°C, and 1,931kPa (280 psig), respectively. This injection continued through late August of 2013 when wellhead pressures were intentionally increased to approximately 5,516 kPa (800 psig) at approximately 984 Lpm (260 gpm). From September 12 to September 24, 2013 cold well water was injected. The average surface injection temperature was approximately 12°C. On September 25, 2013 injection of the warmer plant water was resumed. This was continued through the rest of 2013 and into 2014. Between April 1, 2014 and April 4, 2014, a higher rate hydraulic stimulation was conducted. Colder water (~10°C) was injected at rates of 20 bpm to 30 bpm (3,178 Lpm to 4,770 Lpm) at wellhead pressures of 5,861 kPa (850 psig) over approximately 24 hours. Microseismic activity was recorded near the Tertiary-Precambrian contact. Subsequently, injection of water from the plant was resumed. As of mid-January, 2015, over 666 million liters (176 million gallons) have been injected into the well. The fate of this water is the subject of ongoing numerical analyses and continuous site monitoring. Various analyses have been implemented to monitor and assess the ongoing stimulation program. Modified Hall plot analysis shows increasing conductivity and/or a decreasing skin factor around the wellbore. Since April, 2014, the injectivity index has increased significantly from 0.28 Lpm/kPa (0.5 gpm/psig) to 0.93 Lpm/kPa (1.7 gpm/psig).

enhanced geothermal system↗
DOE OSTI2024

Flavor fragmentation function factorization

A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing along the direction of the Winner-Take-All axis of a jet which is soft safe to all orders, but not collinear safe. Here, we exploit the lack of collinear safety and propose a factorization theorem of perturbative flavor fragmentation functions that resum collinear divergences and describe the evolution of flavor from the short distance of jet production to the long distance at which hadronization occurs. Collinear flavor evolution is governed by a small modification of the DGLAP equations. We present a detailed all-orders analysis and identify exact relations that must hold amongst the various anomalous dimensions by probability conservation and the existence of fixed points of the renormalization group flow. We explicitly validate the factorization theorem at one-loop order, and demonstrate its consistency at two loops in particular flavor channels. Starting at two-loops, constraints on phase space imposed by flavor measurements potentially allow for non-trivial soft contributions, but we demonstrate that they are scaleless and so explicitly vanish, ensuring that soft particles are summed inclusively and all divergences are exclusively collinear in nature. This factorization theorem opens the door to precision calculations with identified flavor in the infrared.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Hadron-in-jet production at partonic threshold

We consider the longitudinal momentum distribution of hadrons inside jets in proton-proton collisions. At partonic threshold large double logarithmic corrections arise which need to be resummed to all orders. We develop a factorization formalism within SCET that allows for the joint resummation of threshold and jet radius logarithms. We achieve next-to-leading logarithmic NLL' accuracy by including non-global logarithms in the leading-color approximation. Overall, we find that the threshold resummation leads to a sizable enhancement of the cross section and a reduced QCD scale dependence, suggesting that the all-order resummation can be important for the reliable extraction of fragmentation functions in global analyses when jet substructure data is included.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

The soft drop groomed jet radius at NLL

We present results for the soft drop groomed jet radius R g at next-to-leading logarithmic accuracy. The radius of a groomed jet which corresponds to the angle between the two branches passing the soft drop criterion is one of the characteristic observables relevant for the precise understanding of groomed jet substructure. We establish a factorization formalism that allows for the resummation of all relevant large logarithms, which is based on demonstrating the all order equivalence to a jet veto in the region between the boundaries of the groomed and ungroomed jet. Non-global logarithms including clustering effects due to the Cambridge/Aachen algorithm are resummed to all orders using a suitable Monte Carlo algorithm. We perform numerical calculations and find a very good agreement with Pythia 8 simulations. We provide theoretical predictions for the LHC and RHIC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗