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Purpose In business, the failure to engage difficult conversations productively can prevent winning in the market and invite the competition to forge ahead. This study aims to identify areas in business where avoiding difficult conversations can put winning out of reach and present guidelines for handling difficult conversations in these domains. Design/methodology/approach This is a conceptual paper that presents guidelines on how to manage difficult conversations effectively. Findings This study shows how to manage difficult conversations with regards to the areas of compensation, performance, strategy and implementation. Originality/value This paper catalogs sources of lost value. Furthermore, this study outlines what is needed to capture such value, and briefly explains the principles for how to transform an organization to build such capability as a core competence.

What is required for effective teaching depends on the goal of the effort, and our criteria for success should be much more demanding than positive ratings from participants. If the goal is to improve participants' effectiveness as negotiators, we need a proven theory and associated skills. In the absence of robust confirming empirical data, which is still mostly lacking, we can take some confidence from qualitative evaluations. But whether or not we have a proven theory, the pedagogical task is complex and challenging, calling for a variety of sophisticated techniques deployed by a skilled instructor committed to joint learning. This article tells the story of some of the instructors' pedagogical learnings in thirty years of teaching the pioneering Negotiation Workshop at Harvard Law School, many of which now have empirical support. It also suggests some areas and tools for more experimentation in future advanced courses.

The notion of an adaptable negotiator, who can respond to any situation he or she encounters, resonates with every negotiation expert. Unexpected things happen in negotiation, and negotiators must be able to adapt in fleet and effective ways. Dealing with the unexpected, responding “in the moment,” and adapting effectively to sudden changes — these are the skills of an improvisational artist, and they are effective skills for negotiators to learn. How can improvisational skills be taught to negotiation students so that they will be able to draw upon these skills in the heat of a negotiation or mediation? By bringing together teachers of improvisation in various disciplines, we explored how improvisation is currently applied and taught in theater, business, and psychotherapy. We then developed some ideas about ways in which teachers of negotiation might begin to incorporate improvisation as part of the negotiation lesson plan.

The presenters on this panel discussed several important additional requirements for the successful implementation of a two-state solution that involves significant relocation of settlers. These requirements include balancing rights among different groups, minimizing the impact of “spoilers,” and providing political compensation to settlers. Presenters also highlighted the relevance of elements of classic negotiation theory to this issue, including thinking creatively about substance and paying appropriate attention to process.

Nuclear electric propulsion (NEP) vehicles will be needed for future manned missions to Mars and beyond. Candidate vehicles must be identified through trade studies for further detailed design from a large array of possibilities. Genetic algorithms have proven their utility in conceptual design studies by effectively searching a large design space to pinpoint unique optimal designs. This research combines analysis codes for NEP subsystems with genetic algorithm-based optimization. Trade studies for a NEP reference mission to the asteroids were conducted to identify important trends, and to determine the effects of various technologies and subsystems on vehicle performance. It was found that the electric thruster type and thruster performance have a major impact on the achievable system performance, and that significant effort in thruster research and development is merited.

The Nuclear Electric Vehicle Optimization Toolset (NEVOT) optimizes the design of all major nuclear electric propulsion (NEP) vehicle subsystems for a defined mission within constraints and optimization parameters chosen by a user. The tool uses a genetic algorithm (GA) search technique to combine subsystem designs and evaluate the fitness of the integrated design to fulfill a mission. The fitness of an individual is used within the GA to determine its probability of survival through successive generations in which the designs with low fitness are eliminated and replaced with combinations or mutations of designs with higher fitness. The program can find optimal solutions for different sets of fitness metrics without modification and can create and evaluate vehicle designs that might never be considered through traditional design techniques. It is anticipated that the flexible optimization methodology will expand present knowledge of the design trade-offs inherent in designing nuclear powered space vehicles and lead to improved NEP designs.

An assessment of nuclear propulsion for Earth to orbit (ETO) missions is presented. Emphasis is placed on nuclear thermal rockets, but other propulsion schemes are briefly addressed. The NERVA, CERMET and particle bed reactor (PER) designs are considered and compared to chemical rocket performance. It is shown that nuclear propulsion schemes have some disadvantages for the ETO mission. This is in contrast to many space missions, which require nuclear propulsion to achieve mission goals. Also, first order system analyses are presented to show the effects of engine performance and propellant storage on required lift-off mass and final mass in orbit. The analyses indicate that specific impulse advantages from a nuclear thermal rocket (NTR) are offset by bulky storage of hydrogen propellant. It is also evident that the NERVA and CERMET type reactors do not merit further consideration for ETO unless breakthroughs in power density and specific power are achieved. The analysis does indicate a superior performance for an unshielded PER design operating at 3200 K, when compared to the Space Shuttle Main Engine (SSME). However, the PER system mass growth is much more sensitive to performance due to propellant density. Background and Historical Perspective Shortly after the achievement of the first fission chain reactor in 1942, members of the Manhattan District Project, including renowned scientists Enrico Fermi and Robert Serber, speculated about the possibility of nuclear fission powered aircraft and rockets.' In May of 1946, the Nuclear Energy for the Propulsion of Aircraft (NEPA) program began under the direction of the United States Air Force (USAF). The NEPA program was directed out of the Oak Ridge National Laboratory. The NEPA program ended in 1951, but much of the work continued in the joint Atomic Energy Commission (AEC) / USAF Aircraft Nuclear Propulsion (ANP) program that followed. ANP had ambitious goals of powering an aircraft using nuclear energy to heat air as the propellant, affording an indefinite range and hover capability, or at least until supplies of coffee and donuts on board were exhausted. The program considered various engine cycles including direct air heating and indirect cycles. ANP was cancelled in March 1961. It is important to note that concurrent to ANP, the Union of Soviet Socialist Republics (USSR) attempted development of a nuclear bomber aircraft, which shared a similar fate. The technical achievements, shortcomings, politics and remaining challenges are well documented in References 1-4. Early in the NEPA program, studies were done to consider nuclear ramjets and rockets in addition to nuclear aircraft. The Lawrence Radiation Laboratory (now Lawrence Livermore National Laboratory) was assigned the responsibility of developing a nuclear powered ramjet under the codename, Pluto project. During the Pluto project, a reactor was developed, built, and demonstrated in a ground test." The investigation of nuclear energy for rockets ended up in the hands of a small group of advocates, primarily at the Los Alamos Scientific Laboratory, who were tasked with evaluating nuclear propulsion for an inter-continental ballistic missile. These investigations led to the USAF sponsored Rover Program, which included nuclear thermal rocket (NTR) development work and the before mentioned Pluto project work. The NTR work for Rover was performed at the Los Alamos Scientific Laboratory and at Livermore. Livermore Laboratory was later directed to focus exclusively on the Pluto project portion of Rover. Senior Researcher, Member AIAA t Senior Researcher, Member AIAA ^Research Scientist, Univ. of Alabama in Huntsville on IPA to NASA MSFC, Member AIAA §Deputy Director, Propulsion Research Center, Senior Member AIAA Copyright © 2001 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U.S. Code. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Government purposes. All other rights are reserved by the copyright owner. (c)2001 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization. Rover later evolved into the Nuclear Engine for Rocket Vehicle Applications (NERVA) project under the direction of NASA in 1958 as part of the space exploration program." NASA continued the NERVA project until 1972. In that time, NERVA accomplished 28 full-power tests with restarts, development of a high temperature reactor fuel and vacuum Isp values of approximately 825 seconds. The NERVA project undoubtedly represents the largest and most productive effort to date on nuclear propulsion of any type, notwithstanding marine propulsion devices such as used in submarines and ships. The NERVA project is responsible for the highest power nuclear reactor ever built, the Phoebus II-A, which was designed for 5000 MW and operated at a power of 4080 MW. Subsequently, the USAF began the Space Nuclear Thermal Propulsion (SNTP) program or Timberwind (unclassified name), which lasted until 1993. The focus of this program was to develop high power density reactors so that thrust to weight ratios required for orbital transfer and potentially upper stage propulsion might be achieved. The reactor type used in Timberwind is called a Particle Bed Reactor (PER) and will be discussed later in this paper. While the Timberwind program did not accomplish the level of development that the NERVA program did, it does represent a significant effort in reactor development and did achieve nuclear tests of single fuel elements, criticality experiments for a prototype 1000 MW core and thermal hydraulics tests in multiple fuel elements to lend observations regarding potential power densities of a PER. Other notable efforts for nuclear propulsion have taken place, but NEPA/ANP, Rover/NERVA and SNTP (Timberwind) were programs that included reactor development and, therefore, represent the most significant contributions to our knowledge on potential flight systems. Of interest in this paper is the number of conceptual vehicles that proposed the use of NTR propulsion for Earth to orbit (ETO) applications. The most comprehensive and ambitious of these concept vehicles is the Aerospace Plane with Nuclear Engines (ASPEN) proposed by Bussard in 1961 in a then classified report. The ASPEN vehicle was a single stage to orbit (SSTO) concept with up to 17% payload fraction to low Earth orbit (LEO). ASPEN proposed an advanced turbojet boost to a ramjet mode to an NTR to orbit. Due to the early timing of the ASPEN concept, much of the weight and sizing information used for ASPEN was speculative and optimistic when compared to technology of the present day. Since it was proposed, many deficits of the analyses have been identified including a subsequent report (ASPEN II) by Bussard, which implies that a 2-stage ETO system would be more appropriate to avoid radiation hazards that were not mitigated in the first proposal. A review and an indepth analysis of the ASPEN vehicle are presented in Reference 8. Other concept vehicle proposals for NTRs in the ETO mission include the Saturn C-3N, a 1961 proposal for the Saturn vehicles to use a 3 stage NTR based on the NERVA technology.' Also, the RITA C, a 1963 concept vehicle by the Douglas Company that proposed an all NTR powered heavy lift vehicle (454,500 kg to 325km orbit).' In recent years, several papers with NTR propulsion schemes for ETO have been published.' Introduction A compelling reason for investigating the applicability of nuclear power in rockets is the incredible energy density of nuclear fuel when compared to chemical combustion energy release. While combustion of hydrogen and oxygen (H2 and O2), has an energy release of 13 MJ/kg, the fissioning of U yields approximately 8 x 10 MJ/kg and the fusion of deuterium and tritium particles (T+D) has a 3.4 x 10 MJ/kg yield. Use of fission energy represents the nearest term application of nuclear power for propulsion application. Several fission based propulsion schemes have been proposed for ETO, including airbreathing, pulsed nuclear explosions and NTRs. NTRs have the highest applicability and, therefore, the bulk of discussion in this paper is focused on them. A small section at the end of the paper addresses other proposed concepts for ETO using different nuclear energy schemes such as airbreathing nuclear rockets, fusion-electric and nuclear explosions. NTRs pass a cooling fluid (or propellant) through a core of material that has been heated by fission. This makes the NTRs effectively a heated gas rocket. Since the NTR is a heat transfer rocket, the propellant can be selected to maximize performance of the propulsion system. It should be noted that this is the primary distinguishing feature of an NTR in contrast to a chemical propulsion rocket. With the present limitations of materials, NTR gas temperatures cannot exceed chemical propulsion gas temperatures (-3650K for H^O^, but because of the selection of propellant, exhaust velocity of chemical American Institute of Aeronautics and Astronautics (c)2001 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization. rockets can be greatly exceeded. This is true when a low molecular weight propellant is chosen compared to the molecular weight of chemical rocket combustion products. As seen from Equation (1), lower molecular weight (MW) and higher temperature increase the exhaust velocity. Equation (1) presents the relationship for an ideal gas flowing through a nozzle from a stagnation pressure and temperature, p0 and T0, to an ideally expanded exit pressure, pe.

The potential for fission-based propulsion systems in opening the solar system to extensive exploration, development, and settlement has been recognized for decades. Work toward a first-generation flight demonstrator is underway at MSFC. Safety is one of the main concerns in the planning, development, and design of the system. The purpose of this research is to design, fabricate, and test a mechanism that will (1) enable complete separation of high reactivity worth nuclear fuel elements from the reactor core during launch and (2) enable reliable insertion of these elements into the core immediately prior to reactor startup. The mechanism will preclude any potential for inadvertent reactor startup during a launch accident. The mechanism thus represents one option for ensuring that the launch of space fission systems is fully safe. Early in the concept phase it became clear that there were many different ways to accomplish fuel separation followed by in-space insertion. The benefits of each method ultimately depended on the overall system (spacecraft or otherwise) design and the mission requirements or uses for the reactor. It became evident that since this information was not yet available the best solution would be to provide multiple designs and let the mission and spacecraft requirements dictate which design to use. With this in mind, two different in-space fueling methods were pursued with the available funding. The first method involves placing the nuclear fuel off axis and external to the fuel. The second method involves replacing some of the fuel with a neutron absorber until the reactor is ready to be fueled. Each method has its benefits and constraints that should be balanced with system and mission requirements.

Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include bimodal nuclear thermal rockets, high specific energy propulsion systems, and pulsed fission propulsion systems. In-space propellant re-supply enhances the effective performance of all systems, but requires significant infrastructure development. Safe, timely, affordable utilization of first-generation space fission propulsion systems will enable the development of more advanced systems. First generation space systems will build on over 45 years of US and international space fission system technology development to minimize cost.

Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total {Delta}V of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present.) All three of these systems have the potential to meet the weight requirement for the trip and to be built in the near term.

This paper reviews the technology options for a fission-based electric propulsion system for interstellar precursor missions. To achieve a total ΔV of more than 100 km/s in less than a decade of thrusting with an electric propulsion system of 10,000 s Isp requires a specific mass for the power system of less than 35 kg/k We. Three possible configurations are described: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. All three of these systems have the potential to meet the specific mass requirements for interstellar precursor missions in the near term. Advanced versions of a fission-based electric propulsion system might travel as much as several light years in 200 years.