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The Mars Hopper: a radioisotope powered, impulse driven, long-range, long-lived mobile platform for exploration of Mars
Planetary exploration mission requirements are becoming more demanding. Due to the increasing cost, the missions that provide mobile platforms that can acquire data at multiple locations are becoming more attractive. Wheeled vehicles such as the MER rovers have proven extremely capable but have very limited range and cannot traverse rugged terrain. Flying vehicles such as balloons and airplanes have been proposed but are problematic due to the very thin atmospheric pressure and the strong, dusty winds present on Mars. The Center for Space Nuclear Research has designed an instrumented platform that can acquire detailed data at hundreds of locations during its lifetime - a Mars Hopper. The Mars Hopper concept utilizes energy from radioisotopic decay in a manner different from any existing radioisotopic power sources—as a thermal capacitor. By accumulating the heat from radioisotopic decay for long periods, the power of the source can be dramatically increased for short periods. The platform will be able to "hop" from one location to the next every 5-7 days with a separation of 5-10 km per hop. Preliminary designs show a platform that weighs around 52 kgs unfueled which is the condition at deployment. Consequently, several platforms may be deployed on a single …
Date:
February 1, 2011
Creator:
Howe, Steven D.; O'Brien, Robert C.; Taitano, William; Crawford, Doug; Jerred, Nathan; Cooley, Spencer et al.
Object Type:
Article
System:
The UNT Digital Library
The Mars Hopper: Development, Simulation and Experimental Validation of a Radioisotope Exploration Probe for the Martian Surface
An advanced exploration probe has been proposed by the Center for Space Nuclear Research (CSNR) to acquire detailed data from the Martian surface and subsurface, ‘hop’ large distances to multiple sites in short periods of time and perform this task repeatedly. Although several similar flying vehicles have been proposed utilizing various power sources and complex designs, e.g. solar-electric and chemical-based, the CSNR’s Mars Hopper is based on a radioisotope thermal rocket (RTR) concept. The Mars Hopper’s design relies on the high specific energies [J/kg] of radioisotopes and enhances their low specific power [W/kg] through the use of a thermal capacitance material to store thermal energy over time. During operation, the RTR transfers the stored thermal energy to a flowing gas, which is then expanded through a converging-diverging nozzle, producing thrust. Between flights, the platform will have ample time to perform in-depth science at each location while the propellant tanks and thermal capacitor recharge. Recharging the propellant tanks is accomplished by sublimation freezing of the ambient CO2 atmosphere with a cryocooler, followed by heating and pressurization to yield a liquid storage state. The proposed Mars Hopper will undergo a ballistic flight, consuming the propellant in both ascent and descent, and by …
Date:
September 1, 2012
Creator:
Jerred, Nathan D.; Cooley, Spencer; O'Brien, Robert C.; Howe, Steven D. & O'Brien, James E.
Object Type:
Article
System:
The UNT Digital Library
ADVANCED RADIOISOTOPE HEAT SOURCE AND PROPULSION SYSTEMS FOR PLANETARY EXPLORATION
The exploration of planetary surfaces and atmospheres may be enhanced by increasing the range and mobility of a science platform. Fundamentally, power production and availability of resources are limiting factors that must be considered for all science and exploration missions. A novel power and propulsion system is considered and discussed with reference to a long-range Mars surface exploration mission with in-situ resource utilization. Significance to applications such as sample return missions is also considered. Key material selections for radioisotope encapsulation techniques are presented.
Date:
September 1, 2010
Creator:
O'Brien, R. C.; Howe, S. D. & Werner, J. E.
Object Type:
Article
System:
The UNT Digital Library
A Flow-Channel Analysis for the Mars Hopper
The Mars Hopper is an exploratory vehicle designed to fly on Mars using carbon dioxide from the Martian atmosphere as a rocket propellant. The propellent gasses are thermally heated while traversing a radioisotope ther- mal rocket (RTR) engine’s core. This core is comprised of a radioisotope surrounded by a heat capacitive material interspersed with tubes for the propellant to travel through. These tubes, or flow channels, can be manu- factured in various cross-sectional shapes such as a special four-point star or the traditional circle. Analytical heat transfer and computational fluid dynamics (CFD) anal- yses were performed using flow channels with either a circle or a star cross- sectional shape. The nominal total inlet pressure was specified at 2,805,000 Pa; and the outlet pressure was set to 2,785,000 Pa. The CO2 inlet tem- perature was 300 K; and the channel wall was 1200 K. The steady-state CFD simulations computed the smooth-walled star shape’s outlet temper- ature to be 959 K on the finest mesh. The smooth-walled circle’s outlet temperature was 902 K. A circle with a surface roughness specification at 0.01 mm gave 946 K and at 0.1 mm yielded 989 K. The The effects of a slightly varied inlet pressure …
Date:
February 1, 2013
Creator:
Cooley, W. Spencer
Object Type:
Book
System:
The UNT Digital Library
Space Exploration
This report discusses the contributions from both the government and private sector towards space exploration.
Date:
March 20, 2015
Creator:
Morgan, Daniel
Object Type:
Report
System:
The UNT Digital Library
Development of the Variable Atmosphere Testing Facility for Blow-Down Analysis of the Mars Hopper Prototype
Recent developments at the Center for Space Nuclear Research (CSNR) on a Martian exploration probe have lead to the assembly of a multi-functional variable atmosphere testing facility (VATF). The VATF has been assembled to perform transient blow-down analysis of a radioisotope thermal rocket (RTR) concept that has been proposed for the Mars Hopper; a long-lived, long-ranged mobile platform for the Martian surface. This study discusses the current state of the VATF as well as recent blow-down testing performed on a laboratory-scale prototype of the Mars Hopper. The VATF allows for the simulation of Mars ambient conditions within the pressure vessel as well as to safely perform blow-down tests through the prototype using CO2 gas; the proposed propellant for the Mars Hopper. Empirical data gathered will lead to a better understanding of CO2 behavior and will provide validation of simulation models. Additionally, the potential of the VATF to test varying propulsion system designs has been recognized. In addition to being able to simulate varying atmospheres and blow-down gases for the RTR, it can be fitted to perform high temperature hydrogen testing of fuel elements for nuclear thermal propulsion.
Date:
February 1, 2013
Creator:
Jerred, Nathan D.; O'Brien, Robert C.; Howe, Steven D. & O'Brien, James E.
Object Type:
Article
System:
The UNT Digital Library
Thermal-hydraulics Analysis of a Radioisotope-powered Mars Hopper Propulsion System
Thermal-hydraulics analyses results produced using a combined suite of computational design and analysis codes are presented for the preliminary design of a concept Radioisotope Thermal Rocket (RTR) propulsion system. Modeling of the transient heating and steady state temperatures of the system is presented. Simulation results for propellant blow down during impulsive operation are also presented. The results from this study validate the feasibility of a practical thermally capacitive RTR propulsion system.
Date:
February 1, 2011
Creator:
O'Brien, Robert C.; Klein, Andrew C.; Taitano, William T.; Gibson, Justice; Myers, Brian & Howe, Steven D.
Object Type:
Article
System:
The UNT Digital Library
Environmental Philosophy and the Ethics of Terraforming Mars: Adding the Voices of Environmental Justice and Ecofeminism to the Ongoing Debate
Questions concerning the ethics of terraforming Mars have received some attention from both philosophers and scientists during recent decades. A variety of theoretical approaches have been supplied by a number of authors, however research pursuant to this thesis has indicated at least two major blindspots in the published literature on the topic. First, a broad category of human considerations involving risks, dangers, and social, political, and economic inequalities that would likely be associated with efforts to terraform Mars have been woefully overlooked in the published literature to date. I attempt to rectify that oversight by employing the interpretive lens of environmental justice to address questions of environmental colonialism, equality in terms of political participation and inclusion in decision making structures, risks associated with technological progressivism, and responses to anthropogenic climate change. Only by including the historically marginalized and politically disenfranchised "voices," of both humans and nonhumans, can any future plan to terraform Mars be deemed ethical, moral or just according to the framework provided by environmental justice. Furthermore, broader political inclusion of this sort conforms to what ecofeminist author Val Plumwood calls the "intentional recognition stance" and provides an avenue through which globally societies can include nonanthropocentric considerations in decision …
Date:
August 2013
Creator:
French, Robert Heath
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
SURFACE GEOPHYSICAL EXPLORATION - COMPENDIUM DOCUMENT
This report documents the evolution of the surface geophysical exploration (SGE) program and highlights some of the most recent successes in imaging conductive targets related to past leaks within and around Hanford's tank farms. While it is noted that the SGE program consists of multiple geophysical techniques designed to (1) locate near surface infrastructure that may interfere with (2) subsurface plume mapping, the report will focus primarily on electrical resistivity acquisition and processing for plume mapping. Due to the interferences from the near surface piping network, tanks, fences, wells, etc., the results of the three-dimensional (3D) reconstruction of electrical resistivity was more representative of metal than the high ionic strength plumes. Since the first deployment, the focus of the SGE program has been to acquire and model the best electrical resistivity data that minimizes the influence of buried metal objects. Toward that goal, two significant advances have occurred: (1) using the infrastructure directly in the acquisition campaign and (2) placement of electrodes beneath the infrastructure. The direct use of infrastructure was successfully demonstrated at T farm by using wells as long electrodes (Rucker et al., 2010, 'Electrical-Resistivity Characterization of an Industrial Site Using Long Electrodes'). While the method was capable …
Date:
October 4, 2011
Creator:
Rucker, D. F. & Myers, D. A.
Object Type:
Report
System:
The UNT Digital Library
Development of a propulsion system and component test facility for advanced radioisotope powered Mars Hopper platforms
Verification and validation of design and modeling activities for radioisotope powered Mars Hopper platforms undertaken at the Center for Space Nuclear Research is essential for proof of concept. Previous research at the center has driven the selection of advanced material combinations; some of which require specialized handling capabilities. The development of a closed and contained test facility to forward this research is discussed within this paper.
Date:
February 1, 2011
Creator:
O'Brien, Robert C.; Jerred, Nathan D. & Howe, Steven D.
Object Type:
Article
System:
The UNT Digital Library
Benchmarking Heavy Ion Transport Codes FLUKA, HETC-HEDS MARS15, MCNPX, and PHITS
Powerful accelerators such as spallation neutron sources, muon-collider/neutrino facilities, and rare isotope beam facilities must be designed with the consideration that they handle the beam power reliably and safely, and they must be optimized to yield maximum performance relative to their design requirements. The simulation codes used for design purposes must produce reliable results. If not, component and facility designs can become costly, have limited lifetime and usefulness, and could even be unsafe. The objective of this proposal is to assess the performance of the currently available codes â PHITS, FLUKA, MARS15, MCNPX, and HETC-HEDS â that could be used for design simulations involving heavy ion transport. We plan to access their performance by performing simulations and comparing results against experimental data of benchmark quality. Quantitative knowledge of the biases and the uncertainties of the simulations is essential as this potentially impacts the safe, reliable and cost effective design of any future radioactive ion beam facility. Further benchmarking of heavy-ion transport codes was one of the actions recommended in the âÂÂReport of the 2003 RIA R&D Workshop".
Date:
June 7, 2013
Creator:
Ronningen, Reginald Martin; Remec, Igor & Heilbronn, Lawrence H.
Object Type:
Report
System:
The UNT Digital Library
Small Body Exploration Technologies as Precursors for Interstellar Robotics
The scientific activities undertaken to explore our Solar System will be the same as required someday at other stars. The systematic exploration of primitive small bodies throughout our Solar System requires new technologies for autonomous robotic spacecraft. These diverse celestial bodies contain clues to the early stages of the Solar System's evolution as well as information about the origin and transport of water-rich and organic material, the essential building blocks for life. They will be among the first objects studied at distant star systems. The technologies developed to address small body and outer planet exploration will form much of the technical basis for designing interstellar robotic explorers. The Small Bodies Assessment Group, which reports to NASA, initiated a Technology Forum in 2011 that brought together scientists and technologists to discuss the needs and opportunities for small body robotic exploration in the Solar System. Presentations and discussions occurred in the areas of mission and spacecraft design, electric power, propulsion, avionics, communications, autonomous navigation, remote sensing and surface instruments, sampling, intelligent event recognition, and command and sequencing software. In this paper, the major technology themes from the Technology Forum are reviewed, and suggestions are made for developments that will have the largest …
Date:
February 15, 2012
Creator:
Noble, Robert & Sykes, Mark V.
Object Type:
Article
System:
The UNT Digital Library
A Journey to Inspire, Innovate, and Discover
On January 14, 2004, President George W. Bush announced a new vision for America’s civil space program that calls for human and robotic missions to the Moon, Mars, and beyond. This vision set forth goals of: returning the Space Shuttle safely to flight; completing the International Space Station (ISS); phasing out the Space Shuttle when the ISS is complete (about 2010); sending a robotic orbiter and lander to the Moon; sending a human expedition to the Moon as early as 2015, but no later than 2020; conducting robotic missions to Mars in preparation for a future human expedition; and conducting robotic exploration across the solar system. Such a focus for the American space program has not existed since the Apollo era and establishes a much-needed direction and purpose for our national space efforts. The Commission sought extensive input for their deliberations, from within the U.S. government and directly from the public in the United States and abroad. The Commission held five televised public hearings, meeting in: Washington, D.C.; Dayton, Ohio; Atlanta, Georgia; San Francisco, California; and New York City. The Commission heard public testimony from 96 individuals representing academia, industry, media, teachers, students, entrepreneurs, astronauts, labor unions, state governments, federal …
Date:
June 2014
Creator:
United States. President's Commission on Implementation of United States Space Exploration Policy.
Object Type:
Report
System:
The UNT Digital Library
Layout-accurate Ultra-fast System-level Design Exploration Through Verilog-ams
This research addresses problems in designing analog and mixed-signal (AMS) systems by bridging the gap between system-level and circuit-level simulation by making simulations fast like system-level and accurate like circuit-level. The tools proposed include metamodel integrated Verilog-AMS based design exploration flows. The research involves design centering, metamodel generation flows for creating efficient behavioral models, and Verilog-AMS integration techniques for model realization. The core of the proposed solution is transistor-level and layout-level metamodeling and their incorporation in Verilog-AMS. Metamodeling is used to construct efficient and layout-accurate surrogate models for AMS system building blocks. Verilog-AMS, an AMS hardware description language, is employed to build surrogate model implementations that can be simulated with industrial standard simulators. The case-study circuits and systems include an operational amplifier (OP-AMP), a voltage-controlled oscillator (VCO), a charge-pump phase-locked loop (PLL), and a continuous-time delta-sigma modulator (DSM). The minimum and maximum error rates of the proposed OP-AMP model are 0.11 % and 2.86 %, respectively. The error rates for the PLL lock time and power estimation are 0.7 % and 3.0 %, respectively. The OP-AMP optimization using the proposed approach is ~17000× faster than the transistor-level model based approach. The optimization achieves a ~4× power reduction for the OP-AMP …
Date:
May 2013
Creator:
Zheng, Geng
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
StarDate, Volume 42, Number 4, July/August 2014
This is a bimonthly publication of the McDonald Observatory discussing research, news, and other topics of interest related to astronomy and science. The publication offers key featured articles, miscellaneous astronomy information, a a current star chart, a calendar of astronomical events, and a Q&A titled Dear Merlin.
Date:
July 2014
Creator:
McDonald Observatory
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Space in Space: Privacy Needs for Long-Duration Spaceflight
Space exploration is a uniquely human activity. As humans continue to push the limits of exploring the unknown, they have sought knowledge supporting the sustenance of life in outer space. New technologies, advancements in medicine, and rethinking what it means to be a “community” will need to emerge to support life among the stars. Crews traveling beyond the Moon will rely on the development of new technologies to support the technological aspects of their missions as well as their quality of life while away from Earth. Likewise, through advancements in medicine, scientists will need to address remaining questions regarding the effects of long-duration spaceflight on the human body and crew performance. Space explorers must learn to utilize these new technologies and medical advancements while learning to adapt to their new environment in space and as a space community. It is important that researchers address these issues so that human survival beyond Earth is not only achievable but so that life among the stars is worth living and sustaining. This thesis addressed these issues in an attempt to extend the trajectory of space exploration to new horizons.
Date:
May 2014
Creator:
Aiken, Jo
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report
Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse ({approx}900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal …
Date:
January 1, 2012
Creator:
Schnitzler, Bruce G.
Object Type:
Report
System:
The UNT Digital Library
Planning For Multiple NASA Missions With Use Of Enabling Radioisotope Power
Since the early 1960’s the Department of Energy (DOE) and its predecessor agencies have provided radioisotope power systems (RPS) to NASA as an enabling technology for deep space and various planetary missions. They provide reliable power in situations where solar and/or battery power sources are either untenable or would place an undue mass burden on the mission. In the modern era of the past twenty years there has been no time that multiple missions have been considered for launching from Kennedy Space Center (KSC) during the same year. The closest proximity of missions that involved radioisotope power systems would be that of Galileo (October 1989) and Ulysses (October 1990). The closest that involved radioisotope heater units would be the small rovers Spirit and Opportunity (May and July 2003) used in the Mars Exploration Rovers (MER) mission. It can be argued that the rovers sent to Mars in 2003 were essentially a special case since they staged in the same facility and used a pair of small launch vehicles (Delta II). This paper examines constraints on the frequency of use of radioisotope power systems with regard to launching them from Kennedy Space Center using currently available launch vehicles. This knowledge may …
Date:
February 1, 2013
Creator:
Johnson, S.G.; Lively, K.L. & Dwight, C.C.
Object Type:
Article
System:
The UNT Digital Library
Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)
Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature …
Date:
July 1, 2010
Creator:
Schnitzler, Bruce G. & Borowski, Stanley K.
Object Type:
Article
System:
The UNT Digital Library
Ongoing Space Nuclear Systems Development in the United States
Reliable, long-life power systems are required for ambitious space exploration missions. Nuclear power and propulsion options can enable a bold, new set of missions and introduce propulsion capabilities to achieve access to science destinations that are not possible with more conventional systems. Space nuclear power options can be divided into three main categories: radioisotope power for heating or low power applications; fission power systems for non-terrestrial surface application or for spacecraft power; and fission power systems for electric propulsion or direct thermal propulsion. Each of these areas has been investigated in the United States since the 1950s, achieving various stages of development. While some nuclear systems have achieved flight deployment, others continue to be researched today. This paper will provide a brief overview of historical space nuclear programs in the U.S. and will provide a summary of the ongoing space nuclear systems research, development, and deployment in the United States.
Date:
October 1, 2011
Creator:
Bragg-Sitton, S.; Werner, J.; Johnson, S.; Houts, Michael G.; Palac, Donald T.; Mason, Lee S. et al.
Object Type:
Article
System:
The UNT Digital Library
U.S. Department of Energy Space and Defense Power Systems Program Ten-Year Strategic Plan, Volume 1 and Volume 2
The Department of Energy's Space and Defense Power Systems program provides a unique capability for supplying power systems that function in remote or hostile environments. This capability has been functioning since the early 1960s and counts the National Aeronautics and Space Administration as one of its most prominent customers. This enabling technology has assisted the exploration of our solar system including the planets Jupiter, Saturn, Mars, Neptune, and soon Pluto. This capability is one-of-kind in the world in terms of its experience (over five decades), breadth of power systems flown (over two dozen to date) and range of power levels (watts to hundreds of watts). This document describes the various components of that infrastructure, work scope, funding needs, and its strategic plans going forward.
Date:
June 2013
Creator:
Dwight, Carla
Object Type:
Report
System:
The UNT Digital Library
Materials characterization activities for %E2%80%9CTake Our Sons&Daughters to Work Day%E2%80%9D 2013.
We created interactive demonstration activities for Take Our Daughters&Sons to Work Day (TODSTWD) 2013 in order to promote general interest in chemistry and also generate awareness of the type of work our laboratories can perform. %E2%80%9CCurious about Mars Rover Curiosity?%E2%80%9D performed an elemental analysis on rocks brought to our lab using the same technique utilized on the planet Mars by the NASA robotic explorer Curiosity. %E2%80%9CFood is Chemistry?%E2%80%9D utilized a mass spectrometer to measure, in seconds, each participant's breath in order to identify the food item consumed for the activity. A total of over 130 children participated in these activities over a 3 hour block, and feedback was positive. This document reports the materials (including handouts), experimental procedures, and lessons learned so that future demonstrations can benefit from the baseline work performed. We also present example results used to prepare the Food activity and example results collected during the Curiosity demo.
Date:
September 1, 2013
Creator:
Mowry, Curtis Dale; Pimentel, Adam S.; Sparks, Elizabeth Schares & Hanlon, Brittany Paula
Object Type:
Report
System:
The UNT Digital Library
Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion
Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified as the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast …
Date:
July 1, 2012
Creator:
Schnitzler, Bruce G. & Borowski, Stanley K.
Object Type:
Article
System:
The UNT Digital Library
NASA: Assessments of Selected Large-Scale Projects
Other written product issued by the Government Accountability Office with an abstract that begins "The National Aeronautics and Space Administration's (NASA) total portfolio of major projects saw cost and schedule growth that remains low compared to GAO's first review of the portfolio. Some projects in this year's portfolio launched within their cost and schedule baselines; however, several others are undergoing replans, which could temper the portfolio's positive performance. For example, the Mars Atmosphere and Volatile EvolutioN project launched on time and cost about $35 million less than its baseline estimate, but NASA officials are reporting that issues with the Ice, Cloud, and Land Elevation Satellite-2 project's primary instrument are driving costs to exceed the original baseline by at least 15 percent, and that the project will miss its committed launch date."
Date:
April 15, 2014
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library