Linked Questions

34 votes
8 answers
6k views

Is it possible to create a relativistic space probe going at least 0.1c with present day technology?

That's pretty much it: Is it possible to create a relativistic space probe going at least 0.1c with present day technology? Present day meaning as of April 2020. If it is actually possible, how ...
123's user avatar
  • 443
10 votes
6 answers
3k views

Using water as a high density storable hydro-lox propellant

Hydro/lox is an excellent fuel choice and has been used in many engine/rockets with high ISP requirements, however, the two biggest drawbacks of the propellant are its density and boil-off. Could this ...
R. Hall's user avatar
  • 822
17 votes
4 answers
5k views

Could JWST stay at L2 "forever"?

Using only reaction wheels powered by solar panel and the sunshield as a sail (in continuous active attitude control) to generate thrust from solar photon pressure in the desired direction, could JWST ...
user avatar
21 votes
2 answers
3k views

Going from LEO to lunar using only low-thrust ion propulsion - can it be done?

@SF.'s question What are the parameters of the new Iodine electrical rocket engine developed by RSC Energia? links to the short RT article 'Ten times cheaper': Russian space company testing iodine ...
uhoh's user avatar
  • 149k
18 votes
1 answer
7k views

What happens to JWST after it runs out of propellant?

JWST will be orbiting L2 which is unstable equilibrium thus will require propellant for station keeping. JWST will carry propellant for 5-10 years. What will happen once it runs out of propellant? ...
daniel.sedlacek's user avatar
4 votes
2 answers
1k views

What could go wrong if someone overpowered an ion engine?

The X-3 ion engine is the most powerful ion engine ever made, and puts out an astounding 5.4 N of force, using 103 kW. It's fuel is inert xenon gas, ionized and heated to a plasma. Now, what would ...
AndrewMaxwellRockets's user avatar
5 votes
1 answer
752 views

Where can I learn to calculate the physics of an ion thruster?

I am trying to build an ion thruster, but I don’t know where to start learning the actual numbers behind one. I know how they work on a basic level, but not much more. Basically I want to be able to ...
saddlepiggy's user avatar
7 votes
1 answer
272 views

Mass ratio of solar-electric versus radioisotope thermo-electric power for propulsion; beyond how many AU do RTGs win?

Solar-electric propulsion has been used several times now in deep space missions. This question explores the scalability in comparison to Radioisotope thermoelectric generation or other nuclear-based ...
uhoh's user avatar
  • 149k
6 votes
1 answer
580 views

What are the parameters of the new Iodine electrical rocket engine developed by RSC Energia?

Several news outlets are reporting Energia Rocket and Space Corporation is nearing completion of a new electrical rocket engine using iodine stored as a solid and vaporized as needed. The new ...
SF.'s user avatar
  • 55.1k
4 votes
1 answer
616 views

What are the advantages of solid iodine propellant and how is it used for ion propulsion?

I was reading about different sources of propellant for ion thrusters, Xenon being the most common. However, in more recent articles I've found more and more mentions of Solid Iodine being used as ion ...
Magic Octopus Urn's user avatar
2 votes
1 answer
581 views

MARS-CAT; What is a Cubesat Ambipolar Thruster and how does it work?

Trying to understand ion thrusters a little, I started looking at https://en.wikipedia.org/wiki/Ion_thruster#Propellants where I saw: The CubeSat Ambipolar Thruster (CAT) used on the Mars Array of ...
uhoh's user avatar
  • 149k
1 vote
1 answer
326 views

For a DAWN-like solar-electric deep space mission, would using propellant particles much heavier than xenon atoms be beneficial?

For deep space missions using ion propulsion that are power-limited, this answer explains that a large mass/charge ratio ($m/q$) species is desirable. The solar-electric propulsion system used by the ...
uhoh's user avatar
  • 149k
0 votes
1 answer
143 views

Was DAWN's power-limited propulsion really limited by power used to accelerate the ions?

The discussion here uses the DAWN mission as a reference for the argument that the power used to accelerate the ions is what's important. I'm curious how many watts were actually used to accelerate ...
uhoh's user avatar
  • 149k
2 votes
1 answer
148 views

Molecular propellant in ion engines

This question was prompted by discussions on this question. Can there be an advantage to using a molecular propellant in an ion engine, as opposed to noble gasses or iodine? (Although iodine actually ...
Greg's user avatar
  • 4,287
2 votes
1 answer
108 views

Can I "tack" towards a laser beam from which I am powering my 100% efficient & massless ion engine?

As far as I know, for light and particles taking special relativity into account: \begin{align} E^2 &= (T + m_0c^2)^2\\ &= p^2 c^2 + m_0^2 c^4 &\text{ (particles)}\\[1.5em] E &= p ...
uhoh's user avatar
  • 149k

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