32
votes
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Land a cubesat on the moon with ion engine
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 ...
29
votes
Accepted
Why do we need dedicated launch vehicles for small satellites?
Why hasn't the small-lift launch vehicles completely replaced by the medium and heavy-lift launch vehicles?
Because small launchers can provide several things:
A small launcher is much cheaper than ...
- 126k
24
votes
Accepted
How serious a problem can outgassing of satellites be?
Its not a mere formality it is unfortunately one of those things that makes satellites expensive. However I wouldn't be surprised if all kinds of nominally incompatible materials have already been ...
- 9,414
19
votes
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Is the Pi really fit for outer space?
Most cubesats are student projects that they want to have for only a matter of a few months at most. That being said, the Pi would likely be very susceptible to Single Event Upsets, SEUs, and thus ...
- 121k
18
votes
Have there ever been cubesats in GEO?
tl;dr As of June 2019, there are zero CubeSats in GEO
The Union of Concerned Scientists has a great database of satellites orbiting the Earth, the smallest satellite that they have in GEO orbit is the ...
- 5,271
17
votes
Why do we need dedicated launch vehicles for small satellites?
Apparently lining up a lot of smallsats for a dedicated big rocket launch is like herding cats. Delays on any of the smallsats delay the overall launch. Hence SpaceX's recent announcement that their ...
- 1,341
16
votes
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How do these cubesats' whip antennas work?
I think most of this can be seen from the picture:
There are two antennae made of spring(blue) steel, so will automatically return to a straight line once the far end is released -the near end of ...
- 470
16
votes
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Moon landing with ion thrusters
This is one of the cases where Kerbal Space Program differs significantly from real world rocketry.
The stock ion engine in KSP has a thrust of 2000 N at 250kg, a thrust-to-weight ratio of 4.9 on the ...
15
votes
Accepted
Are cubesats deployed with fully discharged batteries? Even those on Sherpa?
All cubesats that I have personal knowledge of (including the Planet Labs fleet) were launched with partially charged batteries, typically at around the 50% level that minimizes degradation in storage....
- 10.1k
15
votes
How serious a problem can outgassing of satellites be?
There are a few recorded incidents of spacecraft contamination caused by outgassing.
On Cassini, some haze was noted in test photographs after launch; this was thought to be due to some outgassing ...
- 5,178
15
votes
Reaction Wheels vs. Momentum wheels
I found a great answer to your question from Robert Frost, Instructor and Flight Controller at NASA!
It appears that the difference is one device has a dual purpose of stabilization as well as ...
- 1,870
15
votes
Accepted
Are the Artemis 1 secondary payloads still viable?
TL;DR: (22/11/22 updated edit added at bottom)
Are those batteries now flat?
For some (definitely for one) it could be too late. For the lucky few, they had a recharge.
Did NASA find a way to ...
- 9,542
14
votes
Why is the cubesat structure so expensive?
It's expensive because of the quality requirements.
Material cost is small, low demand is a factor but a structure that size can be made much cheaper than this.
The main cost factors are :
The ...
- 126k
14
votes
Accepted
I'm building a CubeSat for a short 8-day mission in LEO followed by a fairly quick reentry, what range of orbits to consider?
You want a very low altitude, to maximize drag, to make the object deorbit quickly even if you never manage to establish control from the ground. The constraint is that you don't want to go too low, ...
- 7,778
13
votes
Accepted
Could a cubesat propel itself to Mars?
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 ...
- 1,700
13
votes
How do these cubesats' whip antennas work?
This photo confirms @MikeBrockington's answers: dual antennas, nested when stowed, opposed when deployed.
A later photo at https://www.up.edu.ph/index.php/with-maya-1-flying-high-dost-up-aim-to-train-...
- 11.5k
12
votes
Accepted
Cubesat Launch Costs
For ISRO we have revenue details on few small satellites launched between 2013 to 2015 through an official response in Indian Parliament PDF
VELOX-1 (3U) satellite from Nanyang Technological ...
- 1,727
12
votes
Accepted
How are cubesat electronics protected against the effects of radiation in LEO?
Radiation shielding in a cubesat (and spacecraft in general) is a tricky thing because radiation shielding adds mostly negative factors to the satellite. In general, the heavier your shielding is and ...
- 18k
11
votes
Accepted
Could an articulated permanent magnet work as a low-power cubesat magnetotorquer? Problems?
RAX and RAX-2 and possibly other cubesats launched by the University of Michigan (I can't remember at the moment) used fixed neodymium based magnets on their Z+ axis. Hysteresis was added to dump any ...
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11
votes
Would space exploration benefit by sending small drones instead of huge rockets?
Let's say you have a 6500kg piece of equipment you want to launch into space, but your rocket design can only lift 2500kg to the desired orbit. You can:
Build five of these
Strap them together
Put ...
- 211
11
votes
Accepted
Temperature of a satellite orbiting in low Earth orbit
The temperature development of a satellite in LEO depends on a variety of factors. How (quickly) does the satellite rotate, how much is it in eclipse (night), what kind of radiators or internal heat ...
- 11.5k
11
votes
Why isn't there a rocket to launch a single cubesat?
Along with the scaling of rocket engineering that has SpaceX stacking masses of starlinks into a single rocket with any orbital launch there are some non scaling ground constraints.
Any launch will ...
- 21.4k
11
votes
Why isn't there a rocket to launch a single cubesat?
A rocket that can launch a single cubesat would have to be competitive in the current market. But that market is skewed: cubesats are passengers on launches that usually have one large satellite (the ...
- 126k
10
votes
Accepted
Hyperspectral Imaging from Low Earth Orbit
Here is a way to start.
Choose an altitude or height $h$, say 400 km (if it's deployed from the ISS)
Choose a required spatial resolution $d$ on the ground sufficient to see what it is you'd like to ...
- 149k
10
votes
Accepted
Have there ever been cubesats in GEO?
Edited update:
Have there ever been cubesats in GEO?
Yes, 5 in the period 2021-2023.
As of 2023, there are two operational cubesats in GEO, and three that were operational in GEO:
Ascent, launched ...
- 9,542
10
votes
If there "won't be" rockets to launch individual cubesats, then why did JAXA build exactly that? (SS-520-xx)
The SS-520-5 launcher is not intended to be an operational vehicle.
... the SS-520-5 was also an experiment to construct a minimum system that can be established with a micro-...
- 178k
9
votes
Accepted
Current situation with CoCom regulations and GPS receivers for balloons and cubesats
There is a standard clause included in all GPS receiver manuals regarding COCOM Limits. I cannot find the source of this clause, but since it is worded exactly the same in all the manuals I could find,...
- 23.8k
9
votes
Accepted
How to test the impact of radiation on cubesat's electronics?
TL;DR: The medical accelerators are not suitable.
There are basically two effects of radiation on electronics:
Single event upsets (SEUs)
RAM Memory cells are usually small capacitors (caps) which ...
- 781
9
votes
Accepted
RTOS vs Linux against single event upsets
In general, you want as simple of an OS for any embedded systems application. You want as few features as you can get away with. You are less likely to run into problems that way, don't really need ...
- 121k
9
votes
What regulations, agreements, or other forces can help mitigate "PrankSats"?
For your specific example, the answer is cost. Nobody is going to spend hundreds of millions (or even just 1% of that) just to prank a community of astronomers.
For other examples? What stops China ...
- 11.5k
Only top scored, non community-wiki answers of a minimum length are eligible