Linked Questions

27
votes
10answers
8k views

What were the most inaccurate or accurate things in “The Martian”?

I am curious what the most accurate, versus most inaccurate things that were depicted in the space movie, "The Martian"? I thought the part where he punctures his suit and jets over to the rescue ...
16
votes
2answers
3k views

Why are obsolete geostationary satellites re-orbited above the geostationary belt?

That seems a bit counter-intuitive, because in an orbit above the belt, the satellite would eventually lose gain velocity, so its orbit would intersect the orbital plane of the geostationary ...
8
votes
3answers
1k views

Optimal trajectory for solar electric propulsion?

Consider using solar electric propulsion for, e.g. Earth-Mars trip, or for asteroid retrieval mission. Is there a benefit to first entering an eccentric orbit so that part of the time is spent ...
9
votes
2answers
2k views

Could a cubesat propel itself to Mars?

I wrote the answer below to the question Could a cubesat be propelled to the moon? before realizing that it said Moon and I'd written it for Mars, so I've cloned that question and moved the answer ...
4
votes
3answers
1k views

What delta-v is required to move between Phobos and Deimos?

I wonder how practical it would be for a spacecraft to visit both moons of Mars on the same mission. Areostationary orbit lies between the two moons, and GEO is demanding to reach from LEO.
2
votes
3answers
2k views

What is the gravitational acceleration of the Sun?

What is the gravitational acceleration of the Sun? I've seen numbers such as 274 m/s2, but that doesn't make sense to me seeing that relatively weak sources of spacecraft thrust such as Electric ...
4
votes
1answer
566 views

Ratio of low-thrust slow spiral to Hohmann transfer $\Delta V$?

Going from one circular orbit to another, there are tables out there and equations that give the total $\Delta V$ needed for a two or three impulse maneuver scenario. For a very low thrust propulsion ...
2
votes
1answer
239 views

Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver?

I just read a fascinating comment that I don't understand. In part it says ...the Oberth effect does not depend on the mass of the object. A slow spiral in to a low orbit from a C3 of zero will ...
6
votes
2answers
1k views

CubeSat Orbit Determination

I'm thinking about the feasibility of making a CubeSat to test the EM drive thruster. Assuming the microwave electronics and resonant cavity could be scaled down to CubeSat size (5 watts, let's say), ...
3
votes
1answer
1k views

Delta-V of Starlink Satellites

The recently launched Starlink satellites are designed to use their HAL Ion thrusters to seek their own independent orbits, evade collisions, and de-orbit at the end of their lives. That's a lot of ...
5
votes
1answer
644 views

Spiraling out from circular orbit to escape via low thrust, what is γ (gamma)?

@MarkAdler's comment led me to ask Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver? which resulted in this tidy and efficient @MarkAdler answer which ...
2
votes
2answers
341 views

What are the travel times associated with different low-thrust accelerations going to Mars?

It doesn't have to be an exact answer, but something close to reality would be nice. Specifically I want to know what the travel time to Mars would be using constant firing low-thrust engines. What ...
1
vote
2answers
436 views

Quick and dirty way to estimate flight times for constant acceleration rockets

Thought experiment: Suppose we build a spacecraft with a low thrust electric propulsion and have a flight plan that involves constant acceleration on the first half of the journey, breaking on the ...
3
votes
1answer
251 views

Low-thrust spiraling to escape, is the flight path angle (gamma) at C3=0 always 39 degrees?

@MarkAdler's comment led me to ask Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver? which resulted in this tidy and efficient @MarkAdler answer which ...
5
votes
2answers
260 views

Bringing an asteroid into reasonably low Earth orbit--can it be done?

Assume plenty of delta-v is available but it's very slow. At first glance it looks easy enough, get capture and spiral in. However, we have that big bully in the sky, aka Luna. Is it possible to ...

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