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AI Overview
My 2nd SSTO. How can I give it more delta V when it reaches ...
A Single-Stage-To-Orbit (SSTO) vehicle's payload fraction, the ratio of payload mass to initial mass at liftoff, is a critical factor for its viability. While SSTOs aim for a high payload fraction, achieving a truly competitive one is challenging, often requiring advanced technologies. Typical payload fractions for SSTO vehicles range from 1% to 5%, with some advanced designs potentially reaching 10% or even higher.
Factors Influencing SSTO Payload Fraction:
Propellant Fraction:
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A large portion of an SSTO's mass is dedicated to propellant. High specific impulse (Isp) engines are crucial for reducing the required propellant mass, but even with high Isp, the propellant fraction can still be significant.
Inert Mass Fraction:
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This refers to the mass of the vehicle structure, engines, and other non-propellant components. Reducing the inert mass fraction is vital for increasing the payload fraction.
Engine Technology:
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Advanced engine technologies, like air-breathing engines, offer potential for higher Isp and reduced propellant needs, but they also come with their own set of engineering challenges.
Launch Altitude:
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Launching from a high altitude can significantly improve performance, reducing atmospheric drag and allowing for higher engine performance, which can translate to a higher payload fraction.
Vehicle Design:
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The overall design of the SSTO vehicle, including its aerodynamics and structure, plays a crucial role in maximizing payload fraction.
Examples and Considerations:
Reusable SSTOs:
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Reusable SSTOs face the challenge of balancing reusability with low inert mass. The need for robust structures to withstand multiple flights can make it difficult to achieve high payload fractions.
Expendable SSTOs:
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Expendable SSTOs, where the vehicle is not recovered, can achieve higher payload fractions due to lower structural requirements, but at the cost of reusability.
Air-Breathing Engines:
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Air-breathing engines, which utilize atmospheric oxygen, offer the potential for significant performance gains, but they are complex and require significant technological development.
Nuclear Propulsion:
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Nuclear thermal or nuclear electric propulsion systems offer the potential for very high Isp, which could drastically improve SSTO payload fractions, but they present their own set of challenges and safety concerns.
In essence, while achieving a high payload fraction for an SSTO vehicle is difficult, it is a key factor in determining its economic viability. Advanced technologies and careful design are necessary to push the payload fraction to levels that make SSTOs truly competitive with traditional multi-stage rockets

AI Overview
Mock Mars Rover Takes Desert Test Drive | Space
The "Scarecrow" rover is a testbed for NASA's Curiosity Mars rover. It's a full-scale replica of Curiosity, but stripped down and without an onboard computer, allowing engineers to test its mobility and suspension performance in a Mars-like environment without the risk to the actual rover. It's designed to weigh the same on Earth as Curiosity weighs on Mars, accounting for the difference in gravity.
Here's a more detailed explanation:
Purpose:
Scarecrow is used to evaluate the rover's mobility and suspension system. This includes testing its ability to climb slopes, traverse different types of terrain, and handle various driving conditions.
Design:
It's a full-scale replica of the Curiosity rover, but without the complex computer brain. This makes it lighter and allows engineers to focus solely on the mechanical aspects of mobility.
Weight:
Scarecrow is designed to weigh the same on Earth as Curiosity weighs on Mars. This is crucial for accurately simulating how Curiosity will behave in the Martian environment.
Testing Location:
Scarecrow is tested in the Mars Yard at NASA's Jet Propulsion Laboratory (JPL), a simulated Martian landscape that includes rocks, slopes, and other obstacles.
Benefits:
By testing with Scarecrow, engineers can identify potential problems and refine the rover's driving capabilities before sending it to Mars, minimizing risks to the actual Curiosity rover.
Example:
In one instance, Scarecrow was used to test a new traction control algorithm designed to reduce wheel wear on the Mars Curiosity rove

AI Overview
Do we have enough silver, copper, and other materials to ...
Solar panels require several types of metals for construction, including aluminum, steel, copper, and silver. Aluminum and steel are often used for the frames and support structures, while copper and silver are crucial for wiring and electrical contacts within the solar cells. Additionally, minor metals like indium, gallium, and tellurium are used in specific types of solar cells.
Here's a more detailed breakdown:
Aluminum:
Used for the frame that holds the solar panel together, providing a lightweight yet durable structure. It is also sometimes used for wiring.
Steel:
Often used in conjunction with aluminum for the support structure or racking system of the solar panel.
Copper:
Essential for wiring and electrical connections within the solar panel and the overall solar array.
Silver:
A key component in the conductive layer of solar cells, facilitating the flow of electricity.
Zinc:
May be used in the solar panel's construction, although its specific role varies.
Minor Metals:
Indium, Gallium, Selenium, Tellurium: These are used in certain types of thin-film solar cells like CIGS (Copper Indium Gallium Selenide) and Cadmium Telluride (CdTe) solar panels.
Cadmium: Used in CdTe solar panels.
Silicon: The most common material for solar cells, formed into wafers and used as a semiconductor to convert sunlight into electricity.
Other Materials:
Glass: Typically used to protect the solar cells from the elements and provide a transparent surface for sunlight to pass through.
Ethylene tetrafluoroethylene (ETFE): A polymer material used in some solar panel designs as a transparent encapsulant.
Nickel: While not directly involved in energy conversion, nickel may be used in plating for corrosion resistance or in the support structures.
Tin: Used to protect contact layers and prevent corrosion

For PhotonBytes...

GW is working on a spreadsheet to calculate a complete SSTO design.

The prototype has run through scenarios with LH2, methane and RP1.

He is looking for ** real ** data on two specifics and perhaps your company can help:

a) mounts for engines which do NOT gimbal
b) mounts for engines with gimbal
3) plumbing to carry fluids from tanks to engines

The spreadsheet depends upon real data to produce reasonable results.

(th)

AI Overview
The Delta rocket family utilizes gimbaled engines to steer the vehicle during launch. The mass of the gimbal mechanism varies depending on the specific engine and rocket configuration, but it generally contributes a small percentage to the overall vehicle mass, typically around 0.1% to 0.5%. The RS-68A engine on the Delta IV Heavy, for example, has a gimbal system that allows for thrust vectoring, enabling the rocket to steer during ascent. While the exact mass contribution of the gimbal mechanism to the RS-68A engine isn't explicitly stated, it's a relatively small fraction of the engine's overall mass.
Here's a more detailed breakdown:
Delta IV Heavy:
The Delta IV Heavy uses three RS-68A engines, each capable of producing 2.1 million pounds of thrust. The RS-68A is a gimbaled engine, allowing for thrust vectoring for steering.
Engine Mass:
The RS-68A is a large engine, and the gimbal mechanism is a relatively small part of its overall mass. The RL10B, used on the Delta IV upper stage, has a mass of 664 lbs and includes a large carbon-carbon nozzle extension.
Gimbal Contribution:
Studies and examples suggest that gimbals typically contribute between 0.1% and 0.5% to the total launch mass. For example, in the case of the Antares 100 rocket, gimbals on the NK-33 engines contributed about 0.16% of the liftoff mass.
Delta II:
The Delta II used the RS-27 engine, and later the upgraded RS-27A, which also employed a gimbaled system for steering. The RS-27A produced 1,054 kN (237,000 lbf) of thrust.
Other Factors:
The mass of the gimbal mechanism can also be influenced by factors such as the size and complexity of the actuators, hydraulic systems, and other associated components

AI Overview
Delta family of rockets: engine mount mass
Determining the exact mass of engine mounts within the Delta family of rockets can be difficult because the manufacturer often considers this information proprietary, and rarely discloses it as a separate component. However, related data can be analyzed to infer some insights into their mass:
1. Engine dry mass
Delta IV RS-68 Engine: The RS-68 engine used in the Delta IV Common Booster Core has a dry mass of 6,604 kg.
Delta RS-27A Engine: The RS-27A engine used in the 7000 and 8000 series Delta rockets has a dry mass of 1,091 kg.
Delta II RS-27A Engine: The RS-27A engine featured in the Delta II rocket has a dry mass of 1,146 kg.
Delta IV RL10B-2 Engine: The RL10B-2 engine utilized in the Delta IV's second stage has a dry mass of 301 kg.
2. Structural considerations
Engine mounts, along with other structural components like the motor cases, are designed to withstand the extreme forces and vibrations generated during launch and flight.
Material selection for these components is crucial and includes high-strength options such as steel, aluminum, and alloys like Inconel and Titanium.
3. Comparison with overall vehicle mass
The engine dry mass represents a relatively small fraction of the overall mass of a Delta rocket. For example, the Delta IV Heavy has a total launch mass of 733,400 kg.
Even when considering the mass of the engine mount alongside the engine's dry mass, it would still be a minor portion of the rocket's overall weight.
4. Other types of engine mounts
Smaller-scale model rockets utilize simpler engine mount designs. These use materials like cardboard, phenolic resin, or fiberglass, with associated mass implications.
Important Note: The engine mounts are integral to the rocket's structure, designed to safely contain forces and maintain trajectory during flight. While the precise mass might not be publicly available, the information above helps to understand the scope and scale of this critical component

AI Overview
Detailed public information on the specific mass of the fuel plumbing within the Delta IV rocket family is limited in the provided search results. However, the available information provides insights into the fuel systems and related components, allowing for some inferences.
The Delta IV family of rockets utilized liquid hydrogen and liquid oxygen (LH2/LOX) as propellants for both its first stage (Common Booster Core - CBC) and second stage (Delta Cryogenic Second Stage - DCSS). The fuel plumbing would be a critical part of delivering these propellants from the tanks to the engines.
The search results offer information about the Delta IV's fuel systems and their components:
CBC Construction: The CBC includes isogrid aluminum barrels, spun-formed aluminum domes, machined aluminum tank skirts, and a composite centerbody. A cable tunnel carries electrical and signal lines, along with a feedline for liquid oxygen to the RS-68 engine. This indicates fuel plumbing within the structure.
DCSS Construction: The DCSS also uses isogrid aluminum ring forgings, spun-formed aluminum domes, machined aluminum tank skirts, and a composite intertank truss.
Engine Connections: The RS-68 engine on the CBC connects to the thrust structure via a quadrapod thrust frame and is enclosed in a composite conical thermal shield.
RL10B-2 Engine: The RL10B-2 engine, used in the DCSS, weighs 664 lbs. This weight likely includes internal plumbing but doesn't specify the plumbing mass.
Simplified Design: The RS-68 engine was designed for simplified construction, with a lower chamber pressure, efficiency, and a simpler nozzle than the Space Shuttle Main Engine (SSME). It has fewer parts than the SSME and a simpler nozzle. This might suggest a less complex (and potentially lighter) plumbing system for the engine, but it does not specify the mass of the entire fuel delivery system.
Although the exact mass of the fuel plumbing is unavailable, it is a key component constructed with materials like aluminum alloys and composites. The focus on reduced weight in components like the isogrid tanks suggests an effort to optimize the rocket's overall mass.
Additional points:
The Delta IV Heavy, with three Common Booster Cores, has a larger fuel plumbing system than other Delta IV variants.
In conclusion, although the exact mass of the fuel plumbing is not disclosed, it is an integral part of the Delta IV rocket family's structure and performance, designed with weight and reliability in mind.

AI Overview
Detailed public information on the specific mass of the fuel plumbing within the Delta IV rocket family is limited in the provided search results. However, the available information provides insights into the fuel systems and related components, allowing for some inferences.
The Delta IV family of rockets utilized liquid hydrogen and liquid oxygen (LH2/LOX) as propellants for both its first stage (Common Booster Core - CBC) and second stage (Delta Cryogenic Second Stage - DCSS). The fuel plumbing would be a critical part of delivering these propellants from the tanks to the engines.
The search results offer information about the Delta IV's fuel systems and their components:
CBC Construction: The CBC includes isogrid aluminum barrels, spun-formed aluminum domes, machined aluminum tank skirts, and a composite centerbody. A cable tunnel carries electrical and signal lines, along with a feedline for liquid oxygen to the RS-68 engine. This indicates fuel plumbing within the structure.
DCSS Construction: The DCSS also uses isogrid aluminum ring forgings, spun-formed aluminum domes, machined aluminum tank skirts, and a composite intertank truss.
Engine Connections: The RS-68 engine on the CBC connects to the thrust structure via a quadrapod thrust frame and is enclosed in a composite conical thermal shield.
RL10B-2 Engine: The RL10B-2 engine, used in the DCSS, weighs 664 lbs. This weight likely includes internal plumbing but doesn't specify the plumbing mass.
Simplified Design: The RS-68 engine was designed for simplified construction, with a lower chamber pressure, efficiency, and a simpler nozzle than the Space Shuttle Main Engine (SSME). It has fewer parts than the SSME and a simpler nozzle. This might suggest a less complex (and potentially lighter) plumbing system for the engine, but it does not specify the mass of the entire fuel delivery system.
Although the exact mass of the fuel plumbing is unavailable, it is a key component constructed with materials like aluminum alloys and composites. The focus on reduced weight in components like the isogrid tanks suggests an effort to optimize the rocket's overall mass.
Additional points:
The Delta IV Heavy, with three Common Booster Cores, has a larger fuel plumbing system than other Delta IV variants.
In conclusion, although the exact mass of the fuel plumbing is not disclosed, it is an integral part of the Delta IV rocket family's structure and performance, designed with weight and reliability in mind.

AI Overview
The Delta rocket family utilizes gimbaled engines to steer the vehicle during launch. The mass of the gimbal mechanism varies depending on the specific engine and rocket configuration, but it generally contributes a small percentage to the overall vehicle mass, typically around 0.1% to 0.5%. The RS-68A engine on the Delta IV Heavy, for example, has a gimbal system that allows for thrust vectoring, enabling the rocket to steer during ascent. While the exact mass contribution of the gimbal mechanism to the RS-68A engine isn't explicitly stated, it's a relatively small fraction of the engine's overall mass.
Here's a more detailed breakdown:
Delta IV Heavy:
The Delta IV Heavy uses three RS-68A engines, each capable of producing 2.1 million pounds of thrust. The RS-68A is a gimbaled engine, allowing for thrust vectoring for steering.
Engine Mass:
The RS-68A is a large engine, and the gimbal mechanism is a relatively small part of its overall mass. The RL10B, used on the Delta IV upper stage, has a mass of 664 lbs and includes a large carbon-carbon nozzle extension.
Gimbal Contribution:
Studies and examples suggest that gimbals typically contribute between 0.1% and 0.5% to the total launch mass. For example, in the case of the Antares 100 rocket, gimbals on the NK-33 engines contributed about 0.16% of the liftoff mass.
Delta II:
The Delta II used the RS-27 engine, and later the upgraded RS-27A, which also employed a gimbaled system for steering. The RS-27A produced 1,054 kN (237,000 lbf) of thrust.
Other Factors:
The mass of the gimbal mechanism can also be influenced by factors such as the size and complexity of the actuators, hydraulic systems, and other associated components