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From a NASA website article... [NERVA]"...demonstrated an effective exhaust velocity of 24,450 ft/sec, far more than any chemically-fueled rocket could achieve." This is in complete contradiction to this article. http://history.nasa.gov/SP-4221/ch3.htm
Exhaust velocity and thrust have nothing to do with one another. Exhaust velocity does, however, scale with efficiency. Nuclear rockets are far more efficient than chemical rockets; they get more thrust per pound of propellant ejected by achieving much higher exhaust velocities. Check out the Wikipedia page on specific impulse.
"Throughput" is not a term seen in rocket circles, but you might be referring to "thrust" or "total impulse". In theoretical terms, a nuclear rocket may be built to any size; in practical terms, NERVA was actually scaled down by a factor of 4 as its efficiency and reliability increased. Need to go faster (Mars)? Run a smaller NERVA engine longer.
Also in practical terms, many people feel that a chemical rocket visit to Mars or even logistical support by chemical rockets of an extended lunar mission are (again, practically speaking) unfeasible. Chemical rockets have to grow so big that they become both unwieldy and unfundable. As chemical mission durations increase, so must radiation shielding and supplies, but then the vehicle size again increases, etc. etc. The chemical bond doesn't have enough energy to even logistically support an extended lunar mission, much less anything beyond. Voronwae ( talk) 02:14, 19 March 2010 (UTC)
From the article:
What does this mean? Was Kiwi the name of a project? Or is this referring to New Zealanders? Cite, please? -- Karada 16:10, 30 June 2007 (UTC)
I've just finished reading Stephen Baxters Voyage and would like to throw something into the mix here. What no-one seems to have noticed (or at least commented on) is that the Apollo-N mission event sequence is taken straight from Apollo 6. Not sure where he got his NERVA stage design from though. He describes a third stage with gimballed(sic) engines, the designs I have seen for Saturn NERVA stages however all use vernier engines for trajectory control. Graham1973 ( talk) 16:26, 3 September 2008 (UTC)
At the time Baxter wrote the novel I'm guessing good sources on NERVA were not available. Voronwae ( talk) 02:01, 19 March 2010 (UTC)
— jhf ( talk) 23:40, 15 April 2009 (UTC)
Should "Manned Mars Mission" be capitalized? —Preceding unsigned comment added by 205.206.130.52 ( talk) 07:13, 29 October 2009 (UTC)
Where does the 40% figure come from? Is there a reference? vttoth ( talk) 12:47, 16 November 2009 (UTC)
At some point I'm going to replace the erroneous specs at the page bottom from Astronautix, as soon as I have proper figures to replace them. I do know that according to the contractor report I cite throughout the page (written by Ben Finger) the stated thrust for NERVA was 75,000 pounds. I guess it's possible that efficiency increased and thrust went way, way up; I'll check that out, too. Voronwae ( talk) 05:28, 19 March 2010 (UTC)
Didn't the Discovery spacecraft use nuclear thermal rocket propulsion? Should it be added to the list of fictional references in this article? Or is this list limited to direct fictional references to the NERVA engine as developed? Karn ( talk) 17:55, 19 May 2010 (UTC)
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The article says:
This is sourced, but is it really correct? It sounds surprising to me. Large quantities of hydrogen had been produced decades earlier for airships, for example. 2A00:23C5:4B91:AB00:7CAF:AD1C:FAC6:A702 ( talk) 19:08, 22 July 2019 (UTC)
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Reviewing |
Reviewer: Kees08 ( talk · contribs) 05:28, 2 August 2019 (UTC)
Image review done. Kees08 (Talk) 01:17, 6 August 2019 (UTC)
Combine these sentences: The SNTP program was terminated in January 1994.[108] About $200 million was spent.[109]
Reviewed down to Space Nuclear Propulsion Office Kees08 (Talk) 05:15, 6 August 2019 (UTC)
Side note, Scott Manley talks about NERVA briefly in his newest video (about the Russian explosion). Kees08 (Talk) 16:32, 13 August 2019 (UTC)
Sources
Sorry, I think I am almost incapable of doing lightweight GA reviews at this point. That's the end of the review though; I think I owe you a reply above, but I will not be generating any new bullet points to address. Kees08 (Talk) 06:09, 16 August 2019 (UTC)
The article states: “By 1955, it had settled on a 1,500 MW design called Old Black Joe. In 1956, this became the basis of 2,700 MW design intended to be the upper stage of an ICBM.”
These MW figures look high to me. Asubmarine reactor may be 150 MW. A commercial nuclear reactor might be as big as 1,000 MW. — 40.142.140.74 ( talk) 23:52, 12 August 2019 (UTC)
Hello. I enjoyed reading this article, but I feel there is a small gap: If NEVA was "flight-certified" and "the engine was deemed ready for integration into a spacecraft", how come in May 2019, $125 million were authorized to rediscover the wheel? It does not say it will continue the project, so that implies the start of a new [unrelated] project. Is this correct? Also, any indication that such engine is being considered for the Deep Space Transport (Orion + propelled Habitat)? Thanks Rowan Forest ( talk) 23:07, 14 August 2019 (UTC)
I have noticed this sentence in the NERVA NRX section ".. resulting in about $2.20 of reactivity lost, the engine could still have been restarted, but the engineers wanted to examine the core." Should this be % ?
(I would like to congratulate all the editors who have written this wonderful article on an amazing piece of technology. I can remember reading about Nerva in my "Peter Farley's Space Annual" in the early 1970s, so this article really takes me back) KreyszigB ( talk) 18:28, 18 August 2019 (UTC)
Senator Clinton P. Anderson and Lieutenant Colonel G. M. Anderson are both shortened to "Anderson" multiple times during the text, and it may not consistently be obvious which of them is intended. In my opinion, some clarification is needed. Perhaps including titles in the shorthands. "Senator Anderson" and "Chairman Anderson"? Elias ( talk) 10:33, 8 October 2021 (UTC)
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117.20.116.114 ( talk) 06:20, 28 September 2023 (UTC)
To be clear, why is there no mention of nuclear rockets in relation to 'Atoms for Peace' and other attempts at giving atomic power a public relations make-over? Also, given how US space rockets at the time had a nasty habit of blowing up - why is there no mention about the wisdom of attempting to place nuclear materials in space? — Preceding unsigned comment added by 2.27.2.5 ( talk) 08:46, 28 September 2023 (UTC)
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nuh uh 193.40.227.94 ( talk) 11:39, 28 September 2023 (UTC)
I assume the NERVA isn't radiation free. Shouldn't a section be added that discusses radiation emissions in the exhaust and any radiation hazards presented to the payloads being propelled? P Todd ( talk) 15:16, 28 September 2023 (UTC)
In addition to the call for a Radiation emissions discussion, the article needs discussion of environmental and health hazards, including the possibility of an unplanned re-entry or explosion of the launch vehicle causing a catastrophe; and what was the impact on workers and the locations of manufacture and testing; the article reads like typical pro-science rah rah; discussion of these and other risks should be prominent, not buried at the end. Skydog0x ( talk) 18:51, 28 September 2023 (UTC)
A fine piece as usual, but what I don't grasp is context. If the engine was done, how did it compare to contemporary engines, capability and costwise? How about to today's? That kind of context would make it easier to understand if canceling it was prudent or foolish.
This scholarship may not exist. I know I grew up assuming that nuclear engines were a dead end. But if they were not, it'd be nice to know what they could do relative to what we had.-- Neopeius ( talk) 20:41, 1 October 2023 (UTC)
NERVA is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so. | ||||||||||||||||
This article appeared on Wikipedia's Main Page as Today's featured article on September 28, 2023. | ||||||||||||||||
| ||||||||||||||||
Current status: Featured article |
This article is rated FA-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
From a NASA website article... [NERVA]"...demonstrated an effective exhaust velocity of 24,450 ft/sec, far more than any chemically-fueled rocket could achieve." This is in complete contradiction to this article. http://history.nasa.gov/SP-4221/ch3.htm
Exhaust velocity and thrust have nothing to do with one another. Exhaust velocity does, however, scale with efficiency. Nuclear rockets are far more efficient than chemical rockets; they get more thrust per pound of propellant ejected by achieving much higher exhaust velocities. Check out the Wikipedia page on specific impulse.
"Throughput" is not a term seen in rocket circles, but you might be referring to "thrust" or "total impulse". In theoretical terms, a nuclear rocket may be built to any size; in practical terms, NERVA was actually scaled down by a factor of 4 as its efficiency and reliability increased. Need to go faster (Mars)? Run a smaller NERVA engine longer.
Also in practical terms, many people feel that a chemical rocket visit to Mars or even logistical support by chemical rockets of an extended lunar mission are (again, practically speaking) unfeasible. Chemical rockets have to grow so big that they become both unwieldy and unfundable. As chemical mission durations increase, so must radiation shielding and supplies, but then the vehicle size again increases, etc. etc. The chemical bond doesn't have enough energy to even logistically support an extended lunar mission, much less anything beyond. Voronwae ( talk) 02:14, 19 March 2010 (UTC)
From the article:
What does this mean? Was Kiwi the name of a project? Or is this referring to New Zealanders? Cite, please? -- Karada 16:10, 30 June 2007 (UTC)
I've just finished reading Stephen Baxters Voyage and would like to throw something into the mix here. What no-one seems to have noticed (or at least commented on) is that the Apollo-N mission event sequence is taken straight from Apollo 6. Not sure where he got his NERVA stage design from though. He describes a third stage with gimballed(sic) engines, the designs I have seen for Saturn NERVA stages however all use vernier engines for trajectory control. Graham1973 ( talk) 16:26, 3 September 2008 (UTC)
At the time Baxter wrote the novel I'm guessing good sources on NERVA were not available. Voronwae ( talk) 02:01, 19 March 2010 (UTC)
— jhf ( talk) 23:40, 15 April 2009 (UTC)
Should "Manned Mars Mission" be capitalized? —Preceding unsigned comment added by 205.206.130.52 ( talk) 07:13, 29 October 2009 (UTC)
Where does the 40% figure come from? Is there a reference? vttoth ( talk) 12:47, 16 November 2009 (UTC)
At some point I'm going to replace the erroneous specs at the page bottom from Astronautix, as soon as I have proper figures to replace them. I do know that according to the contractor report I cite throughout the page (written by Ben Finger) the stated thrust for NERVA was 75,000 pounds. I guess it's possible that efficiency increased and thrust went way, way up; I'll check that out, too. Voronwae ( talk) 05:28, 19 March 2010 (UTC)
Didn't the Discovery spacecraft use nuclear thermal rocket propulsion? Should it be added to the list of fictional references in this article? Or is this list limited to direct fictional references to the NERVA engine as developed? Karn ( talk) 17:55, 19 May 2010 (UTC)
Hello fellow Wikipedians,
I have just modified 2 external links on NERVA. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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Cheers.— InternetArchiveBot ( Report bug) 07:25, 11 November 2017 (UTC)
The article says:
This is sourced, but is it really correct? It sounds surprising to me. Large quantities of hydrogen had been produced decades earlier for airships, for example. 2A00:23C5:4B91:AB00:7CAF:AD1C:FAC6:A702 ( talk) 19:08, 22 July 2019 (UTC)
GA toolbox |
---|
Reviewing |
Reviewer: Kees08 ( talk · contribs) 05:28, 2 August 2019 (UTC)
Image review done. Kees08 (Talk) 01:17, 6 August 2019 (UTC)
Combine these sentences: The SNTP program was terminated in January 1994.[108] About $200 million was spent.[109]
Reviewed down to Space Nuclear Propulsion Office Kees08 (Talk) 05:15, 6 August 2019 (UTC)
Side note, Scott Manley talks about NERVA briefly in his newest video (about the Russian explosion). Kees08 (Talk) 16:32, 13 August 2019 (UTC)
Sources
Sorry, I think I am almost incapable of doing lightweight GA reviews at this point. That's the end of the review though; I think I owe you a reply above, but I will not be generating any new bullet points to address. Kees08 (Talk) 06:09, 16 August 2019 (UTC)
The article states: “By 1955, it had settled on a 1,500 MW design called Old Black Joe. In 1956, this became the basis of 2,700 MW design intended to be the upper stage of an ICBM.”
These MW figures look high to me. Asubmarine reactor may be 150 MW. A commercial nuclear reactor might be as big as 1,000 MW. — 40.142.140.74 ( talk) 23:52, 12 August 2019 (UTC)
Hello. I enjoyed reading this article, but I feel there is a small gap: If NEVA was "flight-certified" and "the engine was deemed ready for integration into a spacecraft", how come in May 2019, $125 million were authorized to rediscover the wheel? It does not say it will continue the project, so that implies the start of a new [unrelated] project. Is this correct? Also, any indication that such engine is being considered for the Deep Space Transport (Orion + propelled Habitat)? Thanks Rowan Forest ( talk) 23:07, 14 August 2019 (UTC)
I have noticed this sentence in the NERVA NRX section ".. resulting in about $2.20 of reactivity lost, the engine could still have been restarted, but the engineers wanted to examine the core." Should this be % ?
(I would like to congratulate all the editors who have written this wonderful article on an amazing piece of technology. I can remember reading about Nerva in my "Peter Farley's Space Annual" in the early 1970s, so this article really takes me back) KreyszigB ( talk) 18:28, 18 August 2019 (UTC)
Senator Clinton P. Anderson and Lieutenant Colonel G. M. Anderson are both shortened to "Anderson" multiple times during the text, and it may not consistently be obvious which of them is intended. In my opinion, some clarification is needed. Perhaps including titles in the shorthands. "Senator Anderson" and "Chairman Anderson"? Elias ( talk) 10:33, 8 October 2021 (UTC)
Italic text
This
edit request has been answered. Set the |answered= or |ans= parameter to no to reactivate your request. |
117.20.116.114 ( talk) 06:20, 28 September 2023 (UTC)
To be clear, why is there no mention of nuclear rockets in relation to 'Atoms for Peace' and other attempts at giving atomic power a public relations make-over? Also, given how US space rockets at the time had a nasty habit of blowing up - why is there no mention about the wisdom of attempting to place nuclear materials in space? — Preceding unsigned comment added by 2.27.2.5 ( talk) 08:46, 28 September 2023 (UTC)
This
edit request has been answered. Set the |answered= or |ans= parameter to no to reactivate your request. |
{{subst:trim|1=
nuh uh 193.40.227.94 ( talk) 11:39, 28 September 2023 (UTC)
I assume the NERVA isn't radiation free. Shouldn't a section be added that discusses radiation emissions in the exhaust and any radiation hazards presented to the payloads being propelled? P Todd ( talk) 15:16, 28 September 2023 (UTC)
In addition to the call for a Radiation emissions discussion, the article needs discussion of environmental and health hazards, including the possibility of an unplanned re-entry or explosion of the launch vehicle causing a catastrophe; and what was the impact on workers and the locations of manufacture and testing; the article reads like typical pro-science rah rah; discussion of these and other risks should be prominent, not buried at the end. Skydog0x ( talk) 18:51, 28 September 2023 (UTC)
A fine piece as usual, but what I don't grasp is context. If the engine was done, how did it compare to contemporary engines, capability and costwise? How about to today's? That kind of context would make it easier to understand if canceling it was prudent or foolish.
This scholarship may not exist. I know I grew up assuming that nuclear engines were a dead end. But if they were not, it'd be nice to know what they could do relative to what we had.-- Neopeius ( talk) 20:41, 1 October 2023 (UTC)