Editing Nuclear thermal rocket (section)

=== Current research in the US since 2000 ===
[[File:Orion docked to Mars Transfer Vehicle.jpg|thumb|upright=1.0|right|Artist's impression of bimodal NTR engines on a [[Mars Transfer Vehicle]] (MTV). Cold launched, it would be assembled in-orbit by a number of Block 2 SLS payload lifts. The [[Orion spacecraft]] is docked on the left.]]
[[File:DRACO spacecraft.jpg|thumb|right|Artist's concept of the Demonstration Rocket for Agile Cislunar Operations (DRACO).]]

Current solid-core nuclear thermal rocket designs are intended to greatly limit the dispersion and break-up of radioactive fuel elements in the event of a catastrophic failure.<ref>{{cite web
|url=https://inldigitallibrary.inl.gov/sites/sti/sti/4731768.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://inldigitallibrary.inl.gov/sites/sti/sti/4731768.pdf |archive-date=2022-10-09 |url-status=live|publisher=Idaho National Laboratory|title=Recent Activities at the Center for Space Nuclear Research for Developing Nuclear Thermal Rockets
|website=inldigitallibrary.inl.gov|access-date=12 June 2017}} {{PD-notice}}</ref>

As of 2013, an NTR for [[interplanetary spaceflight|interplanetary travel]] from Earth orbit to Mars orbit is being studied at [[Marshall Space Flight Center]] with [[Glenn Research Center]].<ref>{{cite web|url=http://www.space-travel.com/reports/NASA_Researchers_Studying_Advanced_Nuclear_Rocket_Technologies_999.html|title=NASA Researchers Studying Advanced Nuclear Rocket Technologies|last=Smith|first=Rick|date=10 January 2013|website=space-travel.com}}</ref> In historical ground testing, NTRs proved to be at least [[specific impulse|twice as efficient]] as the most advanced chemical engines, which would allow for quicker transfer time and increased cargo capacity. The shorter flight duration, estimated at 3–4 months with NTR engines,<ref>{{cite magazine|magazine=National Security Science|url=http://www.lanl.gov/science/NSS/issue1_2011/story4full.shtml|title=Nuclear Rockets: To Mars and Beyond|author=Brian Fishbine |author2=Robert Hanrahan |author3=Steven Howe |author4=Richard Malenfant |author5=Carolynn Scherer |author6=Haskell Sheinberg |author7=Octavio Ramos Jr. |publisher=Los Alamos National Laboratory|date=December 2016|archive-url=https://web.archive.org/web/20120625011034/http://www.lanl.gov/science/NSS/issue1_2011/story4full.shtml|archive-date=25 June 2012}} {{PD-notice}}</ref> compared to 6–9 months using chemical engines,<ref>{{cite web|url=http://image.gsfc.nasa.gov/poetry/venus/q2811.html|title=How long would a trip to Mars take?|publisher=NASA|archive-url=https://web.archive.org/web/20040111085252/https://image.gsfc.nasa.gov/poetry/venus/q2811.html|archive-date=11 January 2004}} {{PD-notice}}</ref> would reduce crew exposure to potentially harmful and difficult to [[radiation shielding|shield]] [[cosmic ray]]s.<ref>{{cite web|url=http://www.adastrarocket.com/aarc/NEP-Mars|title=How Fast Could (Should) We Go to Mars? &#124; Ad Astra Rocket|website=adastrarocket.com|archive-url=https://web.archive.org/web/20131118030419/http://www.adastrarocket.com/aarc/NEP-Mars|archive-date=18 November 2013}}</ref><ref name="arc.aiaa.org">{{cite book |doi=10.2514/6.2013-4076 |chapter=A One-year Round Trip Crewed Mission to Mars using Bimodal Nuclear Thermal and Electric Propulsion (BNTEP) |title=49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference |date=2013 |last1=Burke |first1=Laura M. |last2=Borowski |first2=Stanley K. |last3=McCurdy |first3=David R. |last4=Packard |first4=Thomas |isbn=978-1-62410-222-6 }}</ref><ref name=NTP2012>{{cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120003776.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120003776.pdf |archive-date=2022-10-09 |url-status=live|title=Nuclear Thermal Propulsion (NTP): A Proven Growth Technology for Human NEO / Mars Exploration Missions|publisher=NASA|date=9 April 2012|author1=Borowski, Stanley K.|author2=McCurdy, David R.|author3=Packard, Thomas W.}} {{PD-notice}}</ref><ref>{{cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012928.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012928.pdf |archive-date=2022-10-09 |url-status=live|title=Nuclear Thermal Rocket/Vehicle Characteristics And Sensitivity Trades For NASA's Mars Design Reference Architecture (DRA) 5.0 Study|publisher=NASA|date=16 August 2012|author1=Borowski, Stanley K.|author2=McCurdy, David R.|author3=Packard, Thomas W.}} {{PD-notice}}</ref> NTR engines, such as the [[NERVA|Pewee]] of [[Project Rover]], were selected in the [[Mars Semi-Direct|Mars Design Reference Architecture]] (DRA).<ref name="arc.aiaa.org"/><ref name=NTP2012/><ref name="MarsRoadmap">{{cite web |url=http://www.nasaspaceflight.com/2012/01/sls-exploration-roadmap-pointing-dual-mars-approach/|publisher=NASASpaceFlight.com|access-date=26 January 2012|author=Chris Bergin|date=24 January 2012|title=SLS Exploration Roadmap evaluations provide clues for human Mars missions}}</ref><ref>{{cite web|url=http://www.space-travel.com/reports/NASA_Researchers_Studying_Advanced_Nuclear_Rocket_Technologies_999.html |title=NASA Researchers Studying Advanced Nuclear Rocket Technologies|author=Rick Smith for Marshall Space Flight Center, Huntsville, Alabama (SPX)|date=10 January 2013}}</ref>

In 2017, NASA continued research and development on NTRs, designing for space applications with civilian approved materials, with a three-year, US$18.8 million contract.<ref name=NTP-2017-08>{{cite web |url=http://www.nasa.gov/centers/marshall/news/news/releases/2017/nasa-contracts-with-bwxt-nuclear-energy-to-advance-nuclear-thermal-propulsion-technology.html|title=New NASA Contract Will Advance Nuclear Thermal Propulsion Technology|first=Lee|last=Mohon|date=2 August 2017|publisher=NASA}} {{PD-notice}}</ref>

In 2019, an appropriation bill passed by the [[United States Congress|U.S. Congress]] included US$125 million<ref name=unisci20190703/> in funding for nuclear thermal propulsion research, including planning for a flight demonstration mission by 2024.<ref name=SpaceNews>{{cite news|url=https://spacenews.com/final-fiscal-year-2019-budget-bill-secures-21-5-billion-for-nasa/|title=Final fiscal year 2019 budget bill secures $21.5 billion for NASA|publisher=SpaceNews|date=17 February 2019|access-date=14 August 2019}}</ref>

As of 2021, there has been much interest in nuclear thermal rockets by the [[United States Space Force]] and [[DARPA]] for orbital and cis-lunar uses. In addition to the U.S. military, NASA administrator [[Jim Bridenstine]] has also expressed interest in the project and its potential applications for a future [[Human mission to Mars|mission to Mars]].<ref name=S-2020-Gry>{{cite web|url=https://www.space.com/darpa-nuclear-thermal-rocket-for-moon-contract|title=US military eyes nuclear thermal rocket for missions in Earth-Moon space |first=Mike |last=Wall |date=30 September 2020 |publisher=SPACE.com}}</ref> [[DARPA]] has awarded 2 contracts for their [[Demonstration Rocket for Agile Cislunar Operations]] (DRACO) program, which aims to demonstrate a nuclear thermal propulsion system in orbit: one award in September 2020 to Gryphon Technologies for US$14 million,<ref name=S-2020-Gry/> and another award in April 2021 to General Atomics for US$22 million, both for preliminary designs for the reactor.<ref name=SN-2021-GA>{{cite web|url=https://spacenews.com/general-atomics-wins-darpa-contract-to-design-nuclear-reactor-to-power-missions-to-the-moon/|title=General Atomics wins DARPA contract to develop nuclear reactor to power missions to the moon|first=Sandra|last=Erwin |date=10 April 2021 |publisher=SpaceNews.com}}</ref> Two conceptual spacecraft designs by Blue Origin and Lockheed Martin were selected. Proposals for a flight demonstration of nuclear thermal propulsion in [[Fiscal year|FY]]2026 were due on 5 August 2022.<ref>[https://spacenews.com/darpa-moving-forward-with-development-of-nuclear-powered-spacecraft/ DARPA moving forward with development of nuclear powered spacecraft] Sandra Erwin, SpaceNews. 4 May 2022</ref>

In January 2023, NASA and DARPA announced a partnership on DRACO to demonstrate an NTR engine in space, an enabling capability for NASA crewed missions to Mars.<ref>{{cite web |last1=Bardan |first1=Roxana |title=NASA, DARPA Will Test Nuclear Engine for Future Mars Missions - NASA |url=https://www.nasa.gov/news-release/nasa-darpa-will-test-nuclear-engine-for-future-mars-missions/ |publisher=NASA |date=24 January 2023}}</ref> In July 2023, U.S. agencies announced that [[Lockheed Martin]] had been awarded a $499 million contract to assemble the experimental nuclear thermal reactor vehicle ([[X-NTRV]]) and its engine.<ref>{{Cite web |last=Berger |first=Eric |date=2023-07-26 |title=The US government is taking a serious step toward space-based nuclear propulsion |url=https://arstechnica.com/space/2023/07/nasa-seeks-to-launch-a-nuclear-powered-rocket-engine-in-four-years/ |access-date=2023-07-26 |website=Ars Technica}}</ref>