interestingasfuck @lemm.ee Blaze @reddthat.com 3w ago

A NASA ion engine while under test at the Glenn Research Center. It can propel spacecrafts to speeds of up to 320,000 km per hour

Source: https://en.wikipedia.org/wiki/NEXT_(ion_thruster)

16 comments

It seems weird to me that they would measure a thruster in maximum speed and not by the force is generates. Doesn’t the maximum speed depend on the mass it is propelling and a bunch of other factors like friction and gravity?
- This speed is the Specific Impulse which is a measure of how effective the fuel mass is used. It is equivalent to the effective exhaust velocity, which is basically the mean exhaust velocity as the real exhaust velocity depends on the position in the exhaust. The specific impulse is more often given in seconds like in the Wikipedia page for the thruster and this representation is connected to the speed-based representation by dividing the effective exhaust velocity by the standard gravitational acceleration at sea level. Mass is not present in both of these representations because this way they are the impulse per unit mass of propellant.
  
  Electric thrusters reach very high exhaust velocities, but the fuel mass flow is limited which leads to low thrust. Chemical engines reach high thrust, but their exhaust velocities are quite low in comparison.
- No, that is the time to maximum speed. Maximum speed depends solely on exhaust speed (how fast the particles get accelerated).
  
  And no friction in space. Well, almost none.
  
  What's weird is that they say km/h. Space and rocket stuff is usually in m/s.
  
  The grandparent comment is correct. There is no such thing as engine-specific “maximum speed”. If you add more fuel, you can always go faster (until the speed of light).
  
  You are incorrect. If I am traveling at 90 % speed of light, take a stone and throw it out the back... I am now faster.
Any sort of long continuous thruster can do that in deep space, assuming there's enough fuel / fuel to weight ratio. And ion engines are simply extremely fuel efficient, but also extremely weak in their actual output.
- So it's not likely it has the force for entry and exit
I was going to joke and say: that’s like, what, warp 0.0001.

In the Star Trek universe, warp factors are a way to measure faster-than-light travel. The speed of light is approximately 299,792 kilometers per second (km/s). To convert your given speed of 32,000 km/hr into a warp factor, we need to use the formula that relates warp factor to the speed of light:

v = c * (w^(10/3))

where:

• v is the speed in multiples of the speed of light (c), • w is the warp factor.

First, convert 32,000 km/hr into kilometers per second (km/s):

32,000 km/hr = 32,000 / 3,600 km/s ≈ 8.89 km/s

Now, find the warp factor using the speed of light:

w = (v / c)^(1 / (10/3))

w = (8.89 km/s / 299,792 km/s)^(1 / (10/3))

Calculate the fraction inside the parentheses:

8.89 / 299,792 ≈ 0.00002967

Now raise this to the power of 3/10:

0.00002967^(3/10) ≈ 0.000657

So, approximately:

w ≈ 0.000657

Therefore, a speed of 32,000 km/hr corresponds to a very low warp factor, approximately Warp 0.000657 in the Star Trek scale.
- You are missing a zero. Also, that formatting. Either remove it or use code that can be displayed.
- .
19883.8782 miles per hour for people in the USA.
- I think you got the decimal wrong there. It should be 198,838 Miles per hour.
- Or 349,956 football fields if that helps.
- Fairly sure your decimal point is misplaced
Speed of light is 1,080,000,000 km/hr.

*Or 1.08 terametres/hr.

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