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== Design ==
== Design ==
The Comet would have been capable of putting 254.4 tons into [[low Earth orbit]] and 97.6 tons to [[trans-lunar injection]], roughly twice that of the Saturn V, making it one of the largest rockets ever designed in terms of payload.<ref>{{Cite web|url=https://space.nss.org/lunar-base-studies-1992-first-lunar-outpost-flo/|title=Lunar Base Studies – 1992: First Lunar Outpost (FLO){{!}}National Space Society|language=en-US|access-date=2020-02-26}}</ref> The vehicle resembled a Saturn V, but with engines updated to the [[Rocketdyne F-1#F-1A after Apollo|F-1A]] and [[Rocketdyne J-2#J-2S|J-2S]], stretched first and second stages, an extra engine on the second stage, an increased-diameter third stage, and new side boosters.<ref name=":0" /> Each of the two side boosters had two F-1A engines.<ref name=":1" /> Development costs were expected to be modest due to reliance on [[Apollo program|Apollo]]-era technology.<ref name=":0">{{Cite web|url=http://www.astronautix.com/f/firstlunaroutpost.html|archive-url=https://web.archive.org/web/20160820174234/http://www.astronautix.com/f/firstlunaroutpost.html|url-status=dead|archive-date=August 20, 2016|title=First Lunar Outpost|website=www.astronautix.com|access-date=2020-01-09}}</ref>
The Comet would have been capable of putting 254.4 tons into [[low Earth orbit]] and 97.6 tons to [[trans-lunar injection]], roughly twice that of the Saturn V, making it one of the largest rockets ever designed in terms of payload.<ref>{{Cite web|url=https://space.nss.org/lunar-base-studies-1992-first-lunar-outpost-flo/|title=Lunar Base Studies – 1992: First Lunar Outpost (FLO){{!}}National Space Society|language=en-US|access-date=2020-02-26}}</ref> The vehicle resembled a Saturn V, but with stretched first and second stages, an increased-diameter third stage, and new side boosters. Additionally, the engines were updated to the [[Rocketdyne F-1#F-1A after Apollo|F-1A]] and [[Rocketdyne J-2#J-2S|J-2S]], and a sixth engine was added to the second stage.<ref name=":0" /> Each of the two side boosters had two F-1A engines.<ref name=":1" /> Development costs were expected to be modest due to reliance on [[Apollo program|Apollo]]-era technology.<ref name=":0">{{Cite web|url=http://www.astronautix.com/f/firstlunaroutpost.html|archive-url=https://web.archive.org/web/20160820174234/http://www.astronautix.com/f/firstlunaroutpost.html|url-status=dead|archive-date=August 20, 2016|title=First Lunar Outpost|website=www.astronautix.com|access-date=2020-01-09}}</ref>


A nuclear-powered variant of the third stage, with two 222.5-kN engines, was also considered. It would have reduced the rocket's size, but at a predicted development cost of $2 billion over a chemical-only design. The nuclear option was planned to be developed later to support crewed Mars missions.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=OtaIDwAAQBAJ&q=Comet+HLLV&pg=PA255|title=The Saturn V F-1 Engine: Powering Apollo into History|last=Young|first=Anthony|date=2019-02-19|publisher=Springer|isbn=978-0-387-09630-8|language=en}}</ref> To this end, NASA's [[Glenn Research Center|Lewis Research Center]] established a Nuclear Systems Office to develop and test a fully functional nuclear engine by 2005.
A nuclear-powered variant of the third stage, with two 222.5-kN engines, was also considered. It would have reduced the rocket's size, but at a predicted development cost of $2 billion over a chemical-only design. The nuclear option was planned to be developed later to support crewed Mars missions.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=OtaIDwAAQBAJ&q=Comet+HLLV&pg=PA255|title=The Saturn V F-1 Engine: Powering Apollo into History|last=Young|first=Anthony|date=2019-02-19|publisher=Springer|isbn=978-0-387-09630-8|language=en}}</ref> To this end, NASA's [[Glenn Research Center|Lewis Research Center]] established a Nuclear Systems Office to develop and test a fully functional nuclear engine by 2005.

Revision as of 03:56, 31 December 2022

Comet HLLV
Artist's impression of a Comet HLLV being rolled out of the VAB
FunctionCrew / Cargo Launch Vehicle
Country of originUnited States
Size
Height410 ft (120 m)
Diameter11.5 m (38 ft)
Stages3
Capacity
Payload to LEO
Mass254,400 kg (560,900 lb)
Payload to TLI
Mass60,600–97,600 kg (133,600–215,200 lb)
Launch history
StatusProposed and cancelled
Launch sitesKennedy Space Center
Boosters
Height155 ft (47 m)
Diameter260 in (6,600 mm)
Empty mass75,678 kg (166,841 lb)
Propellant mass985,368 kg (2,172,365 lb)
Powered by2 Rocketdyne F-1A
Maximum thrust12,020 kN (2,700,000 lbf) sea level
PropellantRP-1/LOX
First stage
Height160.4 ft (48.9 m)
Diameter33.0 ft (10.1 m)
Empty mass209,030 kg (460,830 lb)
Propellant mass2,729,770 kg (6,018,110 lb)
Powered by5 Rocketdyne F-1A
Maximum thrust40,050 kN (9,000,000 lbf) sea level
PropellantRP-1/LOX
Second stage
Height103 ft (31 m)
Diameter33.0 ft (10.1 m)
Empty mass60,767 kg (133,968 lb)
Propellant mass634,439 kg (1,398,699 lb)
Powered by6 Rocketdyne J-2S
Maximum thrust7,750 kN (1,740,000 lbf) vacuum
PropellantLH2/LOX
Translunar Injection stage
Height55.6 ft (16.9 m)
Diameter33.0 ft (10.1 m)
Empty mass21,336 kg (47,038 lb)
Propellant mass135,392 kg (298,488 lb)
Powered by1 Rocketdyne J-2S
Maximum thrust1,180 kN (270,000 lbf) vacuum
PropellantLH2/LOX

The Comet HLLV was a proposed super heavy-lift launch vehicle designed for NASA's First Lunar Outpost program, which was in the design phase from 1992 to 1993 under the Space Exploration Initiative. It was a Saturn V-derived launch vehicle with modernized engines, stretched fuel tanks, and strap-on boosters. Its main goal was to support the First Lunar Outpost program and future human mission to Mars. It was designed to be inexpensive and simple while relying on existing technology to lower development costs.[1]

Design

The Comet would have been capable of putting 254.4 tons into low Earth orbit and 97.6 tons to trans-lunar injection, roughly twice that of the Saturn V, making it one of the largest rockets ever designed in terms of payload.[2] The vehicle resembled a Saturn V, but with stretched first and second stages, an increased-diameter third stage, and new side boosters. Additionally, the engines were updated to the F-1A and J-2S, and a sixth engine was added to the second stage.[1] Each of the two side boosters had two F-1A engines.[3] Development costs were expected to be modest due to reliance on Apollo-era technology.[1]

A nuclear-powered variant of the third stage, with two 222.5-kN engines, was also considered. It would have reduced the rocket's size, but at a predicted development cost of $2 billion over a chemical-only design. The nuclear option was planned to be developed later to support crewed Mars missions.[3] To this end, NASA's Lewis Research Center established a Nuclear Systems Office to develop and test a fully functional nuclear engine by 2005.

NLS derived launch vehicle

An alternate version of the launcher based on the then-in-development National Launch System was proposed. NASA's Marshall Spaceflight Center looked into the Comet rocket or a possible configuration with four F-1A boosters added to the basic 2-stage NLS vehicle. The main expected advantage was that the vehicle could rely on technology currently flying rather than having to resurrect 20 year old technology and manufacturing equipment.

References

  1. ^ a b c "First Lunar Outpost". www.astronautix.com. Archived from the original on August 20, 2016. Retrieved 2020-01-09.
  2. ^ "Lunar Base Studies – 1992: First Lunar Outpost (FLO)|National Space Society". Retrieved 2020-02-26.
  3. ^ a b Young, Anthony (2019-02-19). The Saturn V F-1 Engine: Powering Apollo into History. Springer. ISBN 978-0-387-09630-8.