# Tag Info

31

Not a soft landing. A soft landing requires the spacecraft having a thrust-to-weight ratio greater than one (otherwise it just falls faster and faster). Ion engines have a very low thrust to weight ratio, much smaller than one. On the moon, the surface acceleration is 1.625m/s², so the thruster must provide at least 1.625N of force for every kg of spacecraft....

13

I am assuming you mean by propulsion by the CubeSat itself. Not at the moment! Mostly because of the throughput (thruster lifetime) constraint on small Electric Propulsion (EP) thrusters designed for CubeSats. Right now the leading CubeSat EP thruster is the BIT-3 (this is the thruster that will be used to go to the moon on my answer to your original ...

10

This answer has the two-impulse Hohmann transfer $\Delta V$. It is: $$\sqrt{2x\over x+1}+\sqrt{1\over x}-\sqrt{2\over x\left(x+1\right)}-1$$ where $x$ is the ratio of the higher orbit radius to the lower orbit radius, assuming (without loss of generality) that the lower orbit radius is $1$ and $\mu$ is $1$. This answer notes that in the limit of very low ...

6

Take a look at these two: http://esa.github.io/pykep/ by ESA Advanced Concepts Team licensed under the GNU General Public License v3.0. At the library core is the implementation of an efficient solver for the multiple revolutions Lambert’s problem, objects representing direct (Sims-Flanagan), indirect (Pontryagin) and hybrid methods to represent low-thrust ...

5

Let's look at some possible examples, building on @ben's answer and @ Knudsen's answer. We know that the MarCo cubesats were able to navigate from Earth to Mars, with attitude control via reaction wheels and cold gas thrusters science data and image collection communication directly with Earth via a unique pop-up flat high gain antenna 70W of solar power ...

2

From what I can tell from the parameters in your screenshots, the program has performed a perfectly valid optimisation. What's more concerning is that the text in you question doesn't match the parameters clearly shown in the screenshots. If there's a configuration page where does values are actually used, why is this not included in the question? The ...

2

Not the reference you are looking for, but a response to this: Any references and insights would be deeply appreciated! I would like to note that low-thrust phasing in elliptical orbits is "boring", in the sense that the optimal strategy is conceptually simple. For sufficiently low thrust, the phasing orbit does not have time to noticeably ...

2

In practical terms, these hypothetical single-element manoeuvrers are not useful, as one cares very little for what intermediate path one takes through empty space, while the propellant consumption is an absolute bottleneck. Argument of periapsis can be changed the way you describe, by applying zenith thrust at apoapsis or nadir thrust at periapsis: ...

1

Not with an ion engine. There is nothing fundamentally impossible about putting an engine in a cubesat and making it into a lunar lander. However, this is a very difficult feat, nobody has done anything like it -- cubesats with any significant engines are still uncommon though they do exist. It should be noted that rocket fuel or high-pressure gas will make ...

1

Different methods of low thrust optimization are discussed in Chapter 2 of "Low Thrust Trajectory Optimization in Cislunar and Translunar space", a dissertation published in 2018 by Dr. Parrish. In short, there is no analytical solution. There are several methods for low thrust optimization depending on the problem you'd like to solve. For orbits ...

1

The trouble with optimizing low-thrust trajectories is there are so many different possible maneuver profiles that it is very hard to tell whether there might be a better answer hiding behind a slightly different parameterization of the motion. You can find the best choice out of all the options you considered in your model (much easier in some cases than ...

1

There are too many variables, some of them infinitely variable, to arrive at the optimal burn plan. And then you need to incorporate that burn plan into something that can be carried out with a reasonably priced computer (US \$200K is "reasonably priced) than can handle high level radiation. This is not going to be a state of the art computer. What you ...

1

Please be aware of different uses of the phrase "space tug" I've noticed in literature and at conferences. Meaning A is a vehicle resident in space capable of i) rendezvous and docking, ii) manoeuvering and iii) releasing a client. Meaning B is just items ii) and iii) and thus can include spacecraft considered by some to be "just" an upper stage, e.g. ...

1

You might want to check out this MSc research published in 2017: "Feasibility of Reusable Continuous Thrust Spacecraft for Cargo Resupply Missions to Mars." The author's hypothesis was that currently low-thrust engines could be used to for space tugs between the Earth and Mars to send dozens of tons to Mars and return 10 tons back to Earth (if I recall the ...

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