Indian Human Spaceflight Program (HSP)

HariPrasad-1

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No,it won't be. The acceleration by Ion thrusters is very very low when compared to Chemical thrusters, but the final delta-V is much higher when compared to Chemical ones
You messed it up. I simply wrote that gaining higher velocity without faster acceleration is not possible.
 

pipebomb

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not velocity reduction,but acceleration
Nasa has set a max limit of 3g sustained acceleration for its comercial crew program, isro's requirement could be similar. It would be preferable to have a liquid fueled lv for human mission but we work with the tech we have.

Speaking of liquid fueled vehicles, i always wanted to see a clusterd ground lit gslv with 4 or 5( single stearing engine in the middle) vikas engines at core and no second stage. Just a single ce20 upper stage with restart capability. Mungerilal ke haseen sapne.
 

HariPrasad-1

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where did I messed it up?? Also care to explain how gaining higher velocity without faster acceleration is not possible
This is a basic physics. Rocket starts from zero velocity. How can it achive faster velocity without faster acceleration? A can needs to reach 0 to 100 in 15 second. Do you any way to achive it with acceleration of 20 meter per second?
 

Vamsi

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This is a basic physics. Rocket starts from zero velocity. How can it achive faster velocity without faster acceleration? A can needs to reach 0 to 100 in 15 second. Do you any way to achive it with acceleration of 20 meter per second?
then explain how NASA's Dawn spacecraft achieved 11KM/s with just 90mN thrust?? It's acceleration is way too low
 

Super Flanker

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then explain how NASA's Dawn spacecraft achieved 11KM/s with just 90mN thrust?? It's acceleration is way too low
NASA's Dawn spacecraft was Propelled at a speed of 11.46 KM per second (25,640 mph), not 11 kms/s as told by you.

And by the way, achieving speed of a spacecraft is not possible by only an engine on the craft, it can also be achieved by sling-shoting from the orbit of a planet. When we talk about sling-shoting from a planet's orbit than we come to the concept of "Gravity Assist".

"In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense."

gSun7.jpg


So maybe Dawn spacecraft used Gravity Assist to Propel itself to those speeds along with its own engine at the same time.
 

Vamsi

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NASA's Dawn spacecraft was Propelled at a speed of 11.46 KM per second (25,640 mph), not 11 kms/s as told by you.

And by the way, achieving speed of a spacecraft is not possible by only an engine on the craft, it can also be achieved by sling-shoting from the orbit of a planet. When we talk about sling-shoting from a planet's orbit than we come to the concept of "Gravity Assist".

"In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense."

View attachment 157139

So maybe Dawn spacecraft used Gravity Assist to Propel itself to those speeds along with its own engine at the same time.
Dude it clearly achieved a delta V of 11.2KM/s using Electric-propulsiom
 

Super Flanker

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Dude it clearly achieved a delta V of 11.2KM/s using Electric-propulsiom
This is the official website of NASA, they too are mentioning about Gravity Assist. I don't know what you meant by Delta V. Other than the website which I shared, you will find several other sources on the internet which confirm the usage of Gravity Assist.

 

Super Flanker

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This is a basic physics. Rocket starts from zero velocity. How can it achive faster velocity without faster acceleration? A can needs to reach 0 to 100 in 15 second. Do you any way to achive it with acceleration of 20 meter per second?
Another way to achieve acceleration of a space craft in space is by the utilisation of Gravity Assist.

(~Basically you use the gravity of a planet to sling-shot your craft to alter the path and speed of a spacecraft, typically to save propellant and reduce expense~)
 

mokoman

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This is the official website of NASA, they too are mentioning about Gravity Assist. I don't know what you meant by Delta V. Other than the website which I shared, you will find several other sources on the internet which confirm the usage of Gravity Assist.

IMHO @Vamsi is talking about space travel , not liftoff rockets , if u could sustain even 1cm velocity / sec for a day , u will end up reaching 1km/sec .

delta v is change in velocity . since there is no friction in space , once u hit a certain velocity , u will keep that velocity until u want to change it .

its like how on earth u travel by going from point A -> B . in space i guess u can map out travel with accelerating to a certain velocity V , then before reaching destination , decelerate to 0 so on.
 

Super Flanker

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IMHO @Vamsi is talking about space travel , not liftoff rockets , if u could sustain even 1cm velocity / sec for a day , u will end up reaching 1km/sec .

delta v is change in velocity . since there is no friction in space , once u hit a certain velocity , u will keep that velocity until u want to change it .

its like how on earth u travel by going from point A -> B . in space i guess u can map out travel with accelerating to a certain velocity V , then before reaching destination , decelerate to 0 so on.
In space there is no friction because there is no fluid in space, space is a vacuum, for example in space if you manage to accelerate yourself to 10 kms/sec than that means you will be able to travel 10 continuosly.

But like I said again, NASA Already confirmed that they had used Gravity Assist in the mission at one point, the planet they used for Gravity Assist was Mars.
 

Super Flanker

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Several sources have made a comment in the last few days saying that : "Chandrayaan-3 launch by 2022-end, Gaganyaan manned mission in 2024"

SOURCES :-
 

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