by Marcel F. Williams
As the the President, Congress, NASA, and private industry weigh in on what NASA's next crew launch vehicles should be, here is a brief evaluation of the various viable options.
As the the President, Congress, NASA, and private industry weigh in on what NASA's next crew launch vehicles should be, here is a brief evaluation of the various viable options.
Shuttle derived core vehicle (SD-CV) with ACES 41 Service Module (SM) upper stage
ACES 41: Credit ULA (United Launch Alliance)
Launch Reliability: A two stage to orbit launch vehicle with engine out capability in both stages. Combined with a launch abort system for the CM (Command Module), this would be a safer manned launch vehicle than the Ares I and could be the safest manned launched vehicle ever developed.
Environmental Impact: carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water.
Commercial Viability: With a probable payload capacity of 30 tonnes plus, the this vehicle should be capable of easily delivering an Orion capsule, Boeings CST-100 capsule, or a Dream Chaser space plane easily into orbit plus at least 10 to 20 tonnes of liquid hydrogen and oxygen fuel to LEO orbiting fuel depots for manned beyond LEO missions within cis-Lunar space. Hydrogen and oxygen can also be used as backup electric power aboard a space station using fuel cells with water as a valuable by product. Oxygen, of course, could be used to supply air to a space station.
Environmental Impact: carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water.
Commercial Viability: With a probable payload capacity of 30 tonnes plus, the this vehicle should be capable of easily delivering an Orion capsule, Boeings CST-100 capsule, or a Dream Chaser space plane easily into orbit plus at least 10 to 20 tonnes of liquid hydrogen and oxygen fuel to LEO orbiting fuel depots for manned beyond LEO missions within cis-Lunar space. Hydrogen and oxygen can also be used as backup electric power aboard a space station using fuel cells with water as a valuable by product. Oxygen, of course, could be used to supply air to a space station.
Shuttle derived core vehicle (SD-CV) with stretched hypergolic Service Module (SM) upper stage
Launch Reliability: A two stage to orbit vehicle with no engine out capability in the upper hypergolic stage. This makes this an inherently less reliable two stage spacecraft than the SD-CV/ ACES 41 SM but still more reliable than an Ares I.
Environmental Impact: carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water.
Commercial Viability: Should be capable of delivering an Orion capsule, Boeings CST-100 capsule, or a Dream Chaser space plane into orbit.
Atlas V with ACES 41 Service Module (SM) upper stage
Atlas V and ACES 41 with command module (credit: United Launch Alliance)
Launch Reliability: A two stage to orbit launch vehicle with engine out capability only in the second stage.
Environmental Impact: First stage utilizes greenhouse gas polluting RP-1 (Refined Petroleum 1) fuel with liquid oxygen. However, the production of RP-1 rocket fuel from carbon neutral resources may be a possibility in the near future.
Commercial Viability: Should be able to lift an Orion capsule (without the SM) and a Boeing CST-100 into orbit. However, launching the much heavier Dream Chaser space plane with a rear positioned LAS (Launch Abort System) may require additional solid rocket boosters which would inherently lower the space vehicle's launch reliability relative to other vehicles.
Environmental Impact: First stage utilizes greenhouse gas polluting RP-1 (Refined Petroleum 1) fuel with liquid oxygen. However, the production of RP-1 rocket fuel from carbon neutral resources may be a possibility in the near future.
Commercial Viability: Should be able to lift an Orion capsule (without the SM) and a Boeing CST-100 into orbit. However, launching the much heavier Dream Chaser space plane with a rear positioned LAS (Launch Abort System) may require additional solid rocket boosters which would inherently lower the space vehicle's launch reliability relative to other vehicles.
Falcon 9
Launch Reliability: A two stage to orbit vehicle with engine out capability only in the first stage. The Falcon 9 should be inherently safer than the Ares 1.
Environmental impact: Both first and second stages utilizes greenhouse gas polluting RP-1 (Refined Petroleum 1) fuel with liquid oxygen which would make the Falcon 9 the least green of any crew launch vehicle. However, the production of RP-1 rocket fuel from carbon neutral resources may be a possibility in the near future.
Commercial Viability: The Falcon 9's high inherent launch safety should be attractive to customers for manned spaceflights. Space X argues that the Falcon 9 could be the cheapest manned launch vehicle ever developed.
Environmental impact: Both first and second stages utilizes greenhouse gas polluting RP-1 (Refined Petroleum 1) fuel with liquid oxygen which would make the Falcon 9 the least green of any crew launch vehicle. However, the production of RP-1 rocket fuel from carbon neutral resources may be a possibility in the near future.
Commercial Viability: The Falcon 9's high inherent launch safety should be attractive to customers for manned spaceflights. Space X argues that the Falcon 9 could be the cheapest manned launch vehicle ever developed.
Ares I
Man-rated SD-HLV
Launch Reliability: A two stage to orbit vehicle with no engine out capability in the solid rocket booster first stage and no engine out capability in the single engine LOX/LH2 second stage. So the Ares I would be inherently less safe than the SD-CV, Atlas V, and Falcon 9 launch vehicles.
Environmental Impact: Upper stage uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the single solid rocket booster would be relatively tiny compared to the CO2 pollution that would be produced from vehicles such as the Atlas V and the Falcon 9.
Commercial Viability: It seems doubtful that private companies would be attracted to launching humans aboard a spacecraft with a liquid hydrogen/oxygen upper stage on top of a huge solid rocket booster.
Environmental Impact: Upper stage uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the single solid rocket booster would be relatively tiny compared to the CO2 pollution that would be produced from vehicles such as the Atlas V and the Falcon 9.
Commercial Viability: It seems doubtful that private companies would be attracted to launching humans aboard a spacecraft with a liquid hydrogen/oxygen upper stage on top of a huge solid rocket booster.
Man-rated SD-HLV
Launch Reliability: Three boosters are required to reach orbit. And there is with no engine out capability in the two SRBs (solid rocket boosters). This makes the SD-HLV inherently less safe than the Ares I and a lot less reliable than both versions of the SD-CV.
Environmental Impact: Core booster uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the two solid rocket boosters is relatively tiny compared to the CO2 that would be produced from vehicles such as the Atlas V and the Falcon 9.
Commercial Viability: Because of the unnecessary addition of two SRBs, this would be a much more expensive manned launch vehicle than the SD-CV, Atlas V, or a Falcon 9. However, these cost might be mitigated if the cargo shroud also carried valuable cargo such as multiple satellites, hydrogen and oxygen for space depots, and water and oxygen for space stations. With a minimal payload capacity of at least 65 tonnes, the SD-HLV should be able to carry crew plus at least 40 to 50 tonnes of cargo to orbit-- which is much more cargo than the Space Shuttle.
Commercial Viability: Because of the two SRBs, this would be a much more expensive manned launch vehicle than the SD-CV, Atlas V, or a Falcon 9. But like the SD-HLV, these cost might be mitigated if the cargo shroud also carried valuable cargo such as multiple satellites, hydrogen and oxygen for space depots, and water and oxygen for space stations.
Commercial Viability: Because of the unnecessary addition of two SRBs, this would be a much more expensive manned launch vehicle than the SD-CV, Atlas V, or a Falcon 9. However, these cost might be mitigated if the cargo shroud also carried valuable cargo such as multiple satellites, hydrogen and oxygen for space depots, and water and oxygen for space stations. With a minimal payload capacity of at least 65 tonnes, the SD-HLV should be able to carry crew plus at least 40 to 50 tonnes of cargo to orbit-- which is much more cargo than the Space Shuttle.
Sidemount Shuttle
Credit NASA
Launch Reliability: Three boosters are required to reach orbit with no engine out capability in the two solid rocket boosters (SRBs). This makes the SD-HLV statistically not as safe as the Ares I and a lot less safe than an SD-CV. The placement of the crew capsule and LAS (launch abort system) on the side of the external tank also makes the Sidemount less safe than the inline SD-HLV.
Environmental Impact: Core booster uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the two solid rocket boosters is relatively tiny compared to the CO2 that would be produced from vehicles such as the Atlas V and the Falcon 9.Commercial Viability: Because of the two SRBs, this would be a much more expensive manned launch vehicle than the SD-CV, Atlas V, or a Falcon 9. But like the SD-HLV, these cost might be mitigated if the cargo shroud also carried valuable cargo such as multiple satellites, hydrogen and oxygen for space depots, and water and oxygen for space stations.
Man-rated Delta IV Heavy
Launch Reliability: Three core stages and perhaps an upper stage would be required to transport humans to orbit. There would be no engine out capability in the three cores stages. This vehicle would be less inherently safe than the Ares I and only the LAS ( Launch Abort System) makes the Delta IV heavy inherently safer launch than the Space Shuttle.
Environmental impact: carbon neutral liquid hydrogen/oxygen fuel in core stage and upper ACES 41 stage that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water.
Commercial viability: Should be capable of delivering an Orion capsule, Boeing CST-100, or a Dream Chaser space plane into orbit plus 10 to 20 tonnes of liquid hydrogen and oxygen fuel to LEO orbiting fuel depots.
Environmental impact: carbon neutral liquid hydrogen/oxygen fuel in core stage and upper ACES 41 stage that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water.
Commercial viability: Should be capable of delivering an Orion capsule, Boeing CST-100, or a Dream Chaser space plane into orbit plus 10 to 20 tonnes of liquid hydrogen and oxygen fuel to LEO orbiting fuel depots.
Space Shuttle
Launch Reliability: Three boosters are required to reach orbit with no engine out capability in the two solid rocket boosters (SRBs). No LAS (Launch Abort System). However, there has only been one fatal launch accident in the nearly 30 year launch history of the Space Shuttle with no fatal launch accidents in the last 24 years.
Environmental Impact: Core booster uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the two solid rocket boosters is relatively tiny compared to the CO2 that would be produced from vehicles such as the Atlas V and the Falcon 9.
Environmental Impact: Core booster uses carbon neutral liquid hydrogen/oxygen fuel that's easy to derive from carbon neutral resources (nuclear, hydroelectric, wind, solar, etc.) via the electrolysis of water. The CO2 produced from the polymers contained in the two solid rocket boosters is relatively tiny compared to the CO2 that would be produced from vehicles such as the Atlas V and the Falcon 9.
Relative Safety Levels to Low Earth Orbit
Links and References
Safety Level One: SD-CV with ACES 41 (SM) upper stage
Safety Level Two: Atlas V + ACES 41 SM upper stage; Falcon 9
Safety Level Three : Ares I
Safety Level Four: SD-HLV
Safety Level Five: Delta IV Heavy
Safety Level Six: Space Shuttle
The SD-CV and the Delta IV heavy would have the least environmental impact as far as global warming is concerned while the JP-1 fueled Atlas V (first stage) and Falcon 9 (first and second stages) would have the most deleterious greenhouse effect on the environment. While the global environmental impact of manned space launches (less than a dozen per year) is currently meager compared to other manned transportation systems, the emergence of space tourism could dramatically increase the number of manned space launches to hundreds or even thousands by mid-century as the high demand for manned spaceflights begins to dramatically reduce the cost of rocket engines and space vehicles in general. And this doesn't include the the growing demand for commercial and military satellites and space solar power satellites. Therefore, NASA needs to join the US military in helping to develop aerospace fuels that are derived from carbon neutral resources in order to mitigate the environmental impact of global warming from government and private commercial launched space vehicles.
Safety Level Two: Atlas V + ACES 41 SM upper stage; Falcon 9
Safety Level Three : Ares I
Safety Level Four: SD-HLV
Safety Level Five: Delta IV Heavy
Safety Level Six: Space Shuttle
Relative Greenhouse Gas Impact Levels
Of the crew launch options presented above, the SD-CV with an ACES 41 upper stage would have the safest inherent crew launch architecture. The Atlas V, the Falcon 9, and Boeing's SD-CV with a stretched hypergolic SM (Service Module) would be the next most inherently reliable launch vehicles with configurations inherently more reliable than the Ares I. Because of the addition of a LAS (Launch Abort System) the SD-HLV, Sidemount Shuttle, and a man-rated Delta IV heavy would be inherently safer than the Space Shuttle but still less reliable in their architecture than the less complex Ares I.Zero CO2 pollution: SD-CV (both versions); Delta IV Heavy
Relatively Minor CO2 pollution: Space Shuttle, SD-HLV, Ares I, Sidemount Shuttle
Highest CO2 pollution: Falcon 9, Atlas V
Relatively Minor CO2 pollution: Space Shuttle, SD-HLV, Ares I, Sidemount Shuttle
Highest CO2 pollution: Falcon 9, Atlas V
The SD-CV and the Delta IV heavy would have the least environmental impact as far as global warming is concerned while the JP-1 fueled Atlas V (first stage) and Falcon 9 (first and second stages) would have the most deleterious greenhouse effect on the environment. While the global environmental impact of manned space launches (less than a dozen per year) is currently meager compared to other manned transportation systems, the emergence of space tourism could dramatically increase the number of manned space launches to hundreds or even thousands by mid-century as the high demand for manned spaceflights begins to dramatically reduce the cost of rocket engines and space vehicles in general. And this doesn't include the the growing demand for commercial and military satellites and space solar power satellites. Therefore, NASA needs to join the US military in helping to develop aerospace fuels that are derived from carbon neutral resources in order to mitigate the environmental impact of global warming from government and private commercial launched space vehicles.
Links and References
1. Conquering Cis-Lunar Space with Shuttle and ULA Derived Technologies
2. No time for NASA complacency on crew safety
3. National Launch System
4. Heavy Lift Launch Vehicles with Existing Propulsion Systems (Boeing Phantom Works)
5. A Commercially Based Lunar Architecture
6. DIRECT
7. Completed SD HLV assessment highlights low-cost post-shuttle solution
8. Boeing's New HLV Concept could be the DC-3 of Manned Rocket Boosters
9. ULA: Upper Stage Evolution
2. No time for NASA complacency on crew safety
3. National Launch System
4. Heavy Lift Launch Vehicles with Existing Propulsion Systems (Boeing Phantom Works)
5. A Commercially Based Lunar Architecture
6. DIRECT
7. Completed SD HLV assessment highlights low-cost post-shuttle solution
8. Boeing's New HLV Concept could be the DC-3 of Manned Rocket Boosters
9. ULA: Upper Stage Evolution
5 comments:
Question: Would Boeing's SD-CV use SSME's or man rated RS-68 engines? How many engines would be needed? I suppose three ,like the STS, if using SSME's and or four if using man rated RS-68's. Anyway the SD-CV with current 8.4 meter E.T Core could get NASA into L.E.O very soon and cost effective. A block two varient with a stretched, less weight 8.4 meter E.T Core with added SRB's could meet all of our HLV needs for L.E.O assembly for building a very large Deep Space platform. Wow, now I'm sounding like a Jupiter Direct advocate!
BTW, I like the term Rougue when it comes to "Thinking out of the Box"
Marcel, once again, great facts!
Thanks Robbdee!
The Boeing concept would use man-rated RS-68s but they also proposed using the RS-25E for the heavy lift vehicle. The original NLS concept wanted to use expendable SSME (RS-25E).
I don't see the advantage for NASA (and the tax payers) to fund both the development of the RS-25E and a man-rated RS-68. In order for NASA to reduce its cost, it should use the same engines in both the crew launch vehicle and the heavy lift vehicle. So, IMO, NASA needs to choose to develop the RS-25E or the man-rated RS-68-- but not both.
Although I'm not big fan on solid rocket boosters, its really a myth that SRBs are significantly harmful to the environment.
The SRBs from a Space Shuttle flight put approximately 28 tonnes of CO2 into the atmosphere per flight. An Atlas V that places a mere 10 tonnes into orbit, produces about 840 tonnes of CO2 per flight. A hydrocarbon fuel HLV would presumably produce about 10 times that amount.
As far as the chlorine pollution from solid rocket boosters is concerned, both NASA and US military solid rocket booster launches produce about 725 tonnes of chlorine per year. Natural sources of chlorine from volcanoes and other sources produce about 75,000 tonnes of atmospheric chlorine per year. Private industry puts about 300,000 tonnes of chlorine into the atmosphere every year.
You'd have to increase the rate of solid rocket booster launches by more than 40 times the current launch rate just to produce 10% of the amount of atmospheric chlorine that private industry already produces.
Would the Boeing (conception) SD-CV have enough sea level thrust using 3 RS-25D's to put Orion, CTS-100 or Dreamchaser into LEO with usable orbiting fuel load without SRB's? Is congress making the right engine choice to meet the first staging point of a 70MT HLV. I understand the RS-25 has great ISP numbers. But, thrust is lower then RS-68 engine. One factor is that the RS-25 is less then 50% the weight of the RS-68!
The Boeing concept uses four RS-68 engines. You can get a pdf copy of their paper in the links section.
The original NLS (National Launch System) concept, the NLS 2 used 6 expendable RS-25 engines. However, this was a single-stage to orbit vehicle without an upper stage that dropped 4 of its engines on its way to final orbit. So it was not a two stage vehicle as proposed here.
But your are correct, while the new expendable RS-25E would have a thrust slightly higher that the reusable RS-25D, its thrust would still be substantially lower than the RS-68 engine. And I assume that this would remain true even for the probably lower thrust man-rated version of the RS-68.
However, as you also correctly point out, the RS-25 is about half the weight of the RS-68 (saving about 12 tonnes in a four engine configuration) and utilizes fuel about 10% more efficiently which might reduce fuel mass requirements at lift off by nearly 80 tonnes.
However, I still don't think an SD-CV could use just 3 RS-25 engines even with the upper stage. So I think it will require at least 4 to 6 engines.
Boeing proposes using the RS-68 for the crew vehicle and the RS-25E for the heavy lift vehicle with the SRBs. I think it would be wiser for NASA to fund the development of just one engine for both vehicles: either the RS-25E or a man-rated RS-68 in order to reduce production cost after development.
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