# 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....

9

The largest cubesat allowed by the standard for cubesats is 27U. There is none launched in this size to date though. Millennium Space Systems has developed a platform for these but I haven't encountered any news about customers taking up their offer, or alternative constructions of this form factor planned in the near future. It's definitely an open option ...

9

You want to use a X-band communication link from a cubesat in Earth orbit to another cubesat in orbit around Titan? I don't think it is possible, at least at an acceptable data rate. Lets compare this link to a deep space probe down to the DSN antennas in Goldstone, near Madrid and Canberra. Deep space probes use a transmitter with about 10 to 20 W power, ...

8

You'll be definitely better off with thrusters on individual cubesats, when taking the total mass: last stage + payload, into consideration. To create the distance needed, with a single launch, you'll need to put the satellites into an elliptical orbit tangent to the target one, but of period longer or shorter by 1/8 or an integer fraction multiple of 1/8. ...

7

This is the same or similar unphysical stuff as before. Then for 40W power inside cavity, the calculated Thrust T=20.44mN. There is no propellant here. If 40 Watts were in the form of photons, then the thrust would be $P/c$ = 133 nanoNewtons. This generates 105 more momentum per unit time that it's allowed to. What's the final word; does the EmDrive ...

7

There is the joint project of Caltech, University of Surrey and some other companies for development of Autonomously Assembly of a Reconfigurable Space Telescope (AAReST). This project suggests (at the preliminary stage) using a set of about 3U (it much more like 4U) cubesats for orbital mounting of a telescope mirror. The authors use term "docking"...

6

Personal Suggestion - It's always best to learn by getting your hands dirty and since you are a student, do make an effort to start a Student Satellite Project in your college if it does not already have one. With that being said, having been a part of one such endeavor in my college, I can disseminate whatever exposure I have gotten so far. I was a member ...

6

The answer depends on what kind of orientation the satellite needs. If the goal is to know satellite's orientation relative to the Sun (so it can, for example, turn the side with the biggest solar panels towards the Sun for charging), then one Sun sensor is sufficient. Though many sensors would help in having knowledge of the orientation all the time, ...

5

It looks like the atmospheric pressure at the ISS's 400km altitude is in the high vacuum range of 1E-6 torr. (760 torr = 1 bar). This may be somewhat complicated by the fact that the thermosphere wildly varies in temperature. This level, by itself, is good enough for most of the high-vacuum technologies such as electron guns, mass spectrometers, etc, but ...

5

Note this is not a complete answer, but it is much too long and has too much maths for a comment. The summary is that cooling a phone in space is very unlikely to be a problem (in particular the answers which claim that phones won't work in space for thermal reasons are almost certainly wrong), and conductive cooling (by attaching the phone to the structure ...

5

Unlikely The problem with sending a cubesat to Saturn is power. A cubesat isn't large enough to carry a nuclear thermal generator, and almost certainly not large enough to carry enough solar cells to power it in the outer solar system. Consider the Juno probe to Jupiter. Its solar cells weigh 340kg, yet generate only 240W of power at Jupiter, which has ...

5

If re-entry heat destroys most of the cubesat, leaving only the circuit board intact, its flat shape will likely make it tumble and flutter down to earth intact, at a low terminal velocity, without much more heating or aerodynamic load. You could directly measure that speed (at least near the earth, where atmosphere is denser) by dropping it from a big kite ...

5

You only need two, cf. section 3.10.1 "Attitude Estimation Overview" in Schaub and Junkins 3rd edition. Note that each attitude observation is in the form of a unit direction vector. Thus, a single attitude observation will only provide information on two degrees of rotational freedom. Although the observation vector is a three-dimensional vector, ...

4

I do not think an answer can be provided, or at least would be quite hard, for the question as stated. I do not know what is a current popular belief about prices and can not rate the level of misconception. Furthermore, different CubeSat projects can cost very differently. My answer will focus on prices, not beliefs of prices. Distinction has to be made ...

3

There is nothing special about the attitude control of a CubeSat compared to any other satellite. CubeSats just have more stringent size/mass/power constraints which might limit some of your options. For the determination simple CubeSats rely on Coarse Suns Sensors (CSS) or even on the voltages from their solar panels. Magnetometers are also common, ...

3

@Uwe made a clear case why this may not be feasible using the DSN as an example. I'd like to add that some of the assumptions you list in the comments are not correct. I'm not sure how you come up with 470W generation from the solar panels you linked (cubesatshop.com/product/solar-panels), but the numbers listed on their site are most certainly rated for LEO ...

3

Off the top of my head, here are a number of things you would need to address "apart from the electrical specifications". In reality, this is a great case for strong systems engineering in your satellite. Since there will be major tradeoffs between power, pointing, mass, and RF performance/throughput. Materials. This is mostly easy, since by ...

3

ParkinsonSAT is in low Earth orbit, where there is still enough atmosphere that un-powered satellites will lose speed and de-orbit in less than a decade. Given there is a (very thin) atmosphere, the leading edges of the spinning satellite will be hit with more force by atmospheric particles than trailing edges, so net force will slow down any rotation over ...

3

There are too many general questions here that require book-chapter-length-like answers. I would like to specify first: Do you want to calculate antenna performance, antenna pattern, or what exactly? Additionally, which antenna do you have in mind: ground station antenna for an uplink scenario, antenna on-board of the CubeSat for a downlink? In terms of ...

3

I'm getting a bit confused on the difference between reaction wheels and momentum wheels. Reaction wheel and momentum wheel are near synonyms. Manufacturers of reaction wheels / momentum wheels (e.g., Collins Aerospace; other manufacturers are similar) typically do not distinguish between the two because the same device can be used for both purposes. The ...

3

I think this is a great question, still relevant now. This is an addendum to the answers already provided by Hobbes and iKrase. Technical Whilst I think the factors Hobbes has identified are spot on for the space industry in general the quality requirements on a cubesat structure basically come down to "don't get stuck in the launch pod" and "...

3

(This was going to be a comment rather than an "Answer", but it got long...) I'll assume you have or can get the engineering skills, and give a few CubeSat-specific resources. If you haven't seen it yet, NASA's CubeSat 101 has a lot of information about design, licensing, integration, and such. They don't give exhaustive detail there, but it maps ...

3

Because the other answers seem to be having trouble finding cubesats: the MarCO cubesats apparently downlinked to 70m DSN dishes. MarCO A and B were 6U cubesats that acted as comm relays for the Mars Insight lander during entry, descent, and landing. The Iris v2 radio, developed by NASA JPL, consists of five stacked modules with external Solid-State Power ...

3

Most of the CubeSats have Electrical Power System (EPS) as a dedicated module on a single PC104 like PCB. Depending on the required capacity of the secondary (rechargeable) batteries, they can be housed on the same PCB or as additional modules. Solar cell arrays, with bypass (required in case of cell shadowing and failures) and blocking (stopping from ...

2

That's really not an exorbitant price at all for high quality metal parts, with anodizing and plating, produced in small quantity. it looks like there's a reasonable number of parts in the CubeSat frame and some of them don't look super simple.

2

You have to calculate the deltaV that these thrusters can provide you. You can do this by using the Rocket Equation. You need the ISP value of those thrusters and the starting and final mass of your cubesat (i.e. mass when you are deployed in LEO and mass after you have expended all your Xenon). That will give you the maximum available deltaV. This needs to ...

2

You will need to know the impulse you will need. To derive this, you need to know the mass of your probe, and the required delta-v. To know the delta-v you need to know the route you're going to take. Your route will also guide you as to the required thrust to weight ratio you will need at the different points of your flight, which will inform your ...

2

There’s a 2017 federal “Sources Sought” for launch services for TROPICS. The relevant part is: Therefore, 6 to 8 TROPICS CubeSats will be placed in a constellation formation as described in the three scenarios included in the attached document. All of the CubeSats are identical and must be placed into their operational orbit within 60-days (first ...

2

Raspberry Pis have certainly been designed into cubesats but have not tracked down any overall listing of number actually launched, how well they operated or any lessons learned. Related questions include this one on Pi's and this on code design. The three questions overlap, and tie back to hardware design. Hardware side the first task is to ensure the the ...

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