| dc.description.abstract | The Commercial Space Transportation (CST) activities in the United States are increasing and have increased over 50% in the last year. The launches in the United States for commercial purposes are expected to increase another 50% in the next 3-5 years. National Environmental Policy Act (NEPA) environmental assessments do provide the regulatory environmental analysis for launching space vehicles within the United States. However, the environmental impacts from these launches have not been fully characterized. One method to characterize environmental impacts from a system is through conducting a Life Cycle Assessment (LCA) based on an international standard, ISO14040. The results from this environmental LCA will augment the NEPA efforts for launch activities. The European Space Agency uses LCAs to evaluate their environmental impacts or burdens for specific launchers. Instead of evaluating a specific launcher, this study focused on the consumables used for the launch of one space vehicle. Therefore, this study had the overall goal to characterize those environmental burdens and impacts of one space vehicle launch in the United States with emphasis on the Use Phase.
Specific objectives for this environmental life cycle assessment (ELCA) included:
1. To conduct a base-case life cycle environmental inventory and impact assessment of CST activities in the United States based on ISO 14040 and 14044 focused on:
• Use Phase (launch) with six consumables: reusable and expendable rocket boosters; liquid propellants (liquid oxygen/liquid hydrogen (LOx/LH2), liquid oxygen/liquefied natural gas (LOx/LNG), liquid oxygen/kerosene (LOX/RP-1)), water, electricity, and chemicals,
• Use Phase outputs of greenhouse gases, traditional air pollutants (criteria air pollutants), solid and hazardous wastes, water contamination, and noise.
2. To identify a range of impacts due to sensitivity in model inputs (sensitivity analysis).
3. To conduct additional LCAs incorporating “green technologies” to identify strategies for reducing environmental impacts.
4. To operationalize this ELCA and develop an operational tool, space transportation environmental profile for launch (STEP-L) Dashboard.
The research contribution of this study advances knowledge and analytic application of the LCA to U.S. space launch operations. This study is the first ELCA to begin to characterize environmental domain from the launch of one space vehicle. Each of the objectives added new knowledge to identify and illustrate those environmental impacts from CST launch activities in the United States. From the sensitivity analysis, essential data and process information was identified so a U.S. space mission LCA can be more refined for future LCAs and to enhance options for reduced environmental impacts and better decision making in mission profiles and eco-design. Finally, the STEP-Ls generated a quick-look view for operators, environmental professionals, systems engineers, and other decision makers on each of the launch missions evaluated in this study.
SimaPro Software version 8.3.2 and IMPACT2002+ was used to conduct the life cycle inventory and assessment. Data inputs were gathered from public accessible documents, industry websites, technical journals, and textbooks. Each consumable was assessed one-at-a-time (OAT) to determine its environmental impacts per Launch and then all the consumables were analyzed as a whole system per Launch.
The reusable rocket booster impacted the Human health and Resources the most, whereas, the expendable rocket impacted Human health and Climate change damage areas the most. Since the 1st Stage in the reusable rocket was the only element of the rocket that was reused, the mineral extraction was 89% less than the expendable rocket booster.
The propellants, in particular the LOx, and the engine components and their material makeup generate or influence the greatest environmental burden per Launch for a space vehicle launch into orbit. All three propellants impacted Human health and Resources damage areas the most. Comparatively, LH2 influenced the characterization categories and damage areas the least of the three propellants. This result is primarily due the lower quantity of LH2 modeled in this study.
The various chemicals used and stored at the launch facility can make a difference as to the environmental burden. Hydrazine, diesel and liquid nitrogen had the highest impact for the chemicals considered. The Chemicals consumable impacted Human health and Resources damage areas the most.
Finally, electricity and water are minimal contributors to the environmental burden. However, the diesel-generator was the largest contributor of impact within the electricity consumable. Finding another source of electricity for back-up power and other support equipment rather than using the diesel would decrease the environmental impacts significantly. Transportation was evaluated for consumables traveling to the launch facility from the manufacturing. The west and southeast data for both diesel and gasoline trucks were used in this study. The diesel truck on the west showed higher contributions in both the characterization and the damage areas than the diesel truck in the southeast. This higher contribution might be due to the additives and refining processes used to produce the diesel in the west.
A qualitative input using the Delphi Method was applied to compare the base-case results with the results of a panel of selected experts. An online tool, QUALTRICs© was used to administer the Delphi method surveys. The comparison showed the top two damage areas for Delphi Method and SimaPro results agreement were in: the reusable rocket booster impacted Human health, expendable rocket impacted Climate change, LOx/LH2 impacted Human Health and Resources, and the other propellants impacted Resources.
Five sensitivity parameters were evaluated: reusable rocket life uses, electricity substitute for diesel, material composition change for engine, test firings propellant quantity, and chemical quantity changes. The highest influencer was the propellant amount used in a test firing as part of the launch campaign. Scenario analysis was performed on the frequency of launches and number of engines. The results of an expendable rocket with three engines would have more impacts than the reusable rocket booster with 27 engines. Reusability is validated as a key way to minimize environmental burdens.
Green technology recommendations included replace diesel with solar for the electricity, replacing titanium process (Kroll) with the Armstrong® process, replacing conventional manufacturing for parts with 3-D additive manufacturing, and replacing kerosene (RP-1) with methane as a fuel. A notional green technology STEP-L was generated with solar replacement for diesel-generated electricity. The comparison of the green STEP-L with the reusable rocket with LOx/RP-1 results showed less impact to the damage areas. Green notional launch campaign reduced damage areas of Resources by 1.6%, reduced Climate change by 2.1%, reduced Ecosystem quality by 1.6% and reduced Human health by 1.3%. Overall, impact change for all damage areas combined is 1.5%. The STEP-L for the notional launch campaign with green technology additions generated slight reductions in impact to all damage areas. Even though the reductions appear small, adding a green technology to a full launch campaign can provide a meaningful decrease in environmental impacts. The framework for inserting the green technology recommendations can be transferred to other similar government operations.
Finally, the STEP-L Dashboard provides a way for operators and planners to determine the environmental damage from the consumables as an operational system. The Dashboard input can be changed according to the operational scenario at the launch operation to allow for quick identification of each consumable's contribution to damage areas. | |
