What is (VASIMR) VASIMR is and electromagnetic thruster for spacecraft propulsion. It uses radio waves to ionize and heat a propellant. The magnetic fields is used to accelerate the resulting plasma to generate thrust. It is only one of many electric proplsion rockets.
Why do we need (VASIMR) The future applications of VASIMR is endless. You can think of VASIMR as a in space rocket VASIMR is not able to lift payloads from Earth due to it low thrust-to-weight ratio and its needs to operate in a vacuum. It fuction would probly be used as a upper stage for cargo. reducing the fule requirements for in-space transportation. VASIMR technology could be the breakthough techology that would reduce travel time to Mars from 2.5 years to just about 5 mounths.
What are the possibilities of (VASIMR) The possibilities point to endless future of exploration. As I just talk about VASIMR can be used to send future astronauts to Mars. VASIMR can be used in many more ways here a few. VASIMR can be used to drag compensation for space stations. VASIMR can be used for a lunar cargo delivery mission. Ultra fast deep space robotic missions.The possibilities are endless.
What are the risk with (VASIMR) he risk with VASIMR is the same as any conventral rocket. The radiation risk will be high as we leave Low Earth Orbit (LEO) .The same risk with any rocket VASIMR is safe as any conventral rocket. We as humans have to accept risk with any exploration.
Criticisms of (VASIMR) Robert Zubrin is critic of VASIMR claming that it is less efficinet the other electric thrusters wich are now operational. He has also stated that electric propulsion is not necssary to get to Mars.He has also stated that there a lack of a suitable power source to power VASIMR. He states that power is lacking and there needs to be more advancements in reactor desgin and devleopment
I’m doing this homework assignment and I’ve used NASAs CEARUN rocket program to output 3 things. Flame temp, molecular weight of products, and specific impulse. Held constant is the chamber pressure and expansion ratio pe/pa=1.
The independent variable is the equivalence ratio, the fuel/air ratio compared to the stoichiometric ratio. What I don’t understand is why the specific impulse increases with the equivalence ratio? My combustion products are liquid oxygen and liquid hydrogen so increase the equivalence ratio decreases the molecular weight of my products and also decreases the flame temperature. I cannot find a good paper to explain this trend online. If anyone can help me understand why specific impulse increases with the equivalence ratio I would be very thankful.
I’m using imperial units.
So, Impulse_specific=Impulse_total/(m_propellant*g)
Impulse_total has units of lb*sec m_propellant has units of lb g has units of ft/sec^2
After doing dimensional analysis, Impulse_specific has units of s^(3)/(ft). The units of Impulse_specific should be s. What am I doing wrong in terms of unit analysis?
Hey guys, I’m writing a paper on different propulsion systems for rockets and had a question about the formula for Specific Impulse. Before saying anything else i’d like to clarify that i’m a freshman engineering student so i’m not too bright lol. But anyways, I’m reading a journal where it compares Chemical, Nuclear Thermal and Electric propulsion and they all list their exhaust speeds. Is the exhaust speed equal to the thrust? or the mass flow rate of the propellant.
Again I’m sorry if this sounds like a retarded question. Thank you all.
I believe it could lead to fuel savings as High specific impulse means better fuel efficiency. Please correct me if I am wrong.
I know there are other threads on this but none of them are answered well.
I'm not entirely sure about the different between a rocket engine's specific impulse and its thrust. But more importantly, I want to understand how these two parameters affect the performance of a rocket. How and why is a rocket with high specific impulse and low thrust different from a rocket wit low specific impulse and high thrust (but equal power?)
This has always confused me and it’s high time I asked the question and got a real answer!
Thanks whoever answers, you will have made my day if I can understand this finally
Someone wrote a summary of the pulsed NTR on Wikipedia, claiming it can "produce a very high specific impulse amplification – even higher than the fission-fragment rocket". But nowhere in the proposal paper is that claim found. Fission fragment rockets can get up to 1.5 million seconds specific impulse, which is much more than a typical solid core NTR can achieve (1000 seconds), so that is a high bar.
If you look at the specific impulse amplification formula, another thing implicitly claimed on Wikipedia but not in the original paper is that the number of pulsations during the time of residence of propellant in the chamber is approximately 1. I don't know if this is true. The fission pulse excites the propellant and this pressure presumably makes it vacate the chamber. But the next pulse comes between 0.001 and 0.0001 seconds later, as a basic estimate. Is it reasonable to assume that this is enough time for the propellant to vacate?
If we take that value to be correct, and optimistic values for pulse amplification and prompt heat (1000 and 6%), then we get specific impulse amplification of 7.8. Using a baseline of 1000 seconds for a conventional solid NTR, this implies a figure of 7,800 seconds for the pulsed NTR. Does this seem right?
(Also, is there a better subreddit for this kind of thing?)
from Ignition page 109 by John D. Clark the third paperback printing.
I tried to post this in /r/AskScience but somehow it wasn't visible =( Edit: Just realized I wrote Mars twice, I meant to ask the difference between Earth and Mars.
Given the stage has the following configuration:
Thrust
741.4 kN (Main)
47.1 kN (Vernier)
Specific impulse
297.999 s (Main)
288.999 s (Vernier)
How would I calculate the total thrust and specific impulse for the stage?
Is it the chemical reaction? Atmospheric drag? Or something else entirely?
Armchair rocketry fan here so sorry if it is a very basic question.
My understanding is that the Specific Impulse (Isp) is inversely proportional to the root of the molecular mass of the reaction mass and proportional to the root of the temperature.
Therefore in low thrust/high-efficiency scenarios (e.g. orbital transfers), you want as high an ISP as possible and therefore as light and hot a propellant as possible.
Sorry if this is unclear. I guess what I am asking, is if a standard LOX/H2 rocket uses H2O as its reaction mass (flame temperature ~3500K, molar mass 18), than it seems that you can greatly increase efficiency without needing NERVA etc but with conventional methods which heat H2 to a fraction of the temperature (1160K, molar mass 2).
What improvements would you guys try in order for the Starship to hit the 4% mark Elon was talking about?
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I am trying to make a bar graph with clustered bars. I measured three variables repeatedly across 3 participants. I would like to graph the average value for each participant and each variable with error bars showing the standard deviation of each, clustered by the variable name.
My data is organized as follows:
| AVG1 | SD1 | AVG2 | SD2 | AVG3 | SD3 | |
|---|---|---|---|---|---|---|
| Person 1 | 10 | 2 | 15 | 2 | 56 | 7 |
| Person 2 | 25 | 3 | 45 | 4 | 76 | 10 |
| Person 3 | 30 | 1 | 35 | 5 | 23 | 3 |
So ideally I would want three clusters of bars. The first cluster would have 3 bars of height 10 25 and 30 with error bars ranging 8-12, 22-28, and 29-31 repectively. Then I would want the send and3rd variables included in the chart.
The way my data is organized, I get 6 clusters instead of 3 and I cannot adjust the error bars to reflect the differences between individuals/variables.
How can I organize my data to achieve my goal? I have all the raw data still in the same document.
I saw I am supposed to include my excel version on here but I do not know what it is. I am on a PC running Windows 10 though.
So I've changed the qt theme on my arch linux machine (i3wm) using qt5ct and kvantum but for some reason kdenlive is broken when using this, so I need to disable the QT_QPA_PLATFORMTHEME variable for only kdenlive.
is there a way to do this?
Thanks!
I remember reading a while back that the impulse drives are just mini warp bubble generators that kind of work like the phoenix.
Can anyone confirm this?
Is it from atmospheric drag or inherent in the design of the engine or how the fuel/oxidizer combust or something else entirely?
