All Questions
10
questions
3
votes
1
answer
368
views
What am I missing about rocket nozzle isentropic flow?
Playing a bit with Cpropep-Web, something looked wrong to me about how it models isentropic flow through a CD nozzle.
I'm taking the RS-25 characteristics as an example. I ask for a frozen equilibrium ...
3
votes
2
answers
139
views
How much solar radiation hits a spacecraft in transit to Mars?
How can I solve for the amount of radiation that hits a Mars transit vehicle, in transit? What formulas should I use? I am mostly focused on solar radiation.
- 31
11
votes
1
answer
327
views
How much is known about those liquid metal droplets orbiting the Earth? (e.g. sizes, composition, orbits...) Are any actually tracked?
The question Orbit Guardians - bs, right? mentions a company proposing a smallsat that will capture then give a roughly 200 m/s retrograde "kick" to liquid metal NaK alloy droplets in LEO ...
- 148k
11
votes
1
answer
4k
views
How hard is the hardest ice in the solar system? Is it in Pluto's ice mountains?
NPR's Pluto Has White-Capped Mountains, But Not Because There's Snow includes the following:
"Initially, it seemed logical that this high-altitude frost could form like on the Earth," says ...
- 148k
2
votes
1
answer
102
views
Specific Heat Ratio for a perfect gas mixture
I am reading Rocket Propulsion Elements by George P. Sutton & Oscar Biblarz, 9th Edition. In the fifth chapter, I was introduce to the specific heat ratio k for the perfect gas mixture, Eq. 5-7:
(...
- 23
1
vote
0
answers
436
views
Can Chemical Engineer work on something related to space?
I am an undergraduate student (scientific section) living in Qatar. I have a big interest in astronomy and astrophysics and have participated in the IOAA (International Olympiad on Astronomy and ...
- 11
4
votes
1
answer
503
views
Why might krypton have a lower utilization fraction than xenon for ion propulsion, and what can be done to improve it?
A comment below Why will Starlink satellites use krypton instead of xenon for electric propulsion? links to the 2011 preprint A Performance Comparison of Xenon and KryptonPropellant on an SPT-100 Hall ...
- 148k
1
vote
1
answer
455
views
What is a lithium fed GIT? How does it work?
This answer to What is the maximum speed an ion engine can propel a spacecraft at? mentions the following:
Lithium fed GIT (gridded ion thrusters) have demonstrated 50,000 - 80,000 seconds of ISP (...
- 148k
5
votes
1
answer
289
views
Got Milk? Why is the term "colloid" used in "Colloid or Electrospray thruster"?
From this answer to the question "Difference between colloid thrusters and electro spray thrusters" I've extracted the following:
According to the Wikipedia article Colloid thruster they are the same ...
- 148k
0
votes
3
answers
1k
views
Why don't ion thrusters use exothermic reactions directly to ionize the gas and heat up the plasma?
Ion thrusters require a lot of energy because of their high exhaust velocities. But why can't they just pump a mixture of hydrogen and xenon into the chamber, mix it with oxygen and burn it? Doesn't ...
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