# Tag Info

26

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 using a large launcher to launch a single small satellite. a dedicated launch, instead of having to share a launch which reduces your choice of final orbits a ...

17

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 one is attached to the white block on the right hand side, and the other to the white block on the top left. The end is glued to an orange piece of string, which ...

15

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 planned Falcon 9 dedicated smallsat launches will launch on schedule regardless of whether all the satellites are ready. https://spacenews.com/spacex-says-...

14

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-more-satellite-builders/ shows that the antennas are about 20 cm long. But a poster in the background of that photo shows another cubesat mock-up with ...

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

Top one is Malaysia, middle one Philippines, bottom is Bhutan. Here's the story in Spacetech Asia's Cubesats from Malaysia, Bhutan & the Philippines on SpaceX’s Dragon launch: Today, at 5.42 a.m. UTC, SpaceX launched its 15th Cargo Resupply Mission (CRS) to the International Space Station (ISS), with the Falcon 9 lofting the Dragon cargo spacecraft into ...

7

As a new user I cannot comment or tweak the original answer, so I'll try my own. Happy update per any recommendations that come up. @uhoh's answer is close, but a few things to note. The TLE tells us the number of orbits per day is 15.50995519 (line 2 columns 53–63)  \frac{24 \frac{hours}{day} * 60 \frac{mins}{hour} }{15.50995519 \frac{orbits}{day}} = ...

6

Our company (Malin Space Science Systems) is collaborating with Stellar Explorations to develop a very small biprop propulsion system for cubesat missions. There is a definite lack of options in this size range, mostly because cubesats have been prohibited from having significant propulsion systems by launch providers or primary launch customer rules up ...

5

To Answer your question: How many spacecraft deployed from the ISS have escaped Earth orbit? None Are there plans for any in the near future? No A short proof: Public Sat-Catalog here You can search by "International Designator = 1998-067" and filter "On-Orbit" you will get every known object released (intentionally or not) by the ISS an the ISS ...

5

In addition to the answer of Mike Brockington that explains how the deployment (likely) works, I'll add this: Note that there are two antennas, wrapped into each other in a circular fashion. Each one is connected to the white blocks on the left and right sides. A 1U cube sat is 10 cm in all dimensions and the antennas seem to be wrapped about one and a ...

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 ...

4

First, you will not be able to detumble without at least one sensor. For CubeSats the normal way to detumble is through the B-dot algorithm which measures the magnetic field change and turns on appropriate magnetorquers to slow down the motion. Since you have to measure the magnetic field to begin with, you've already established a rough attitude in two-...

4

Answering almost a year later... This was a particularly hard launch for JSPOC to track. The systems, processes, databases, etc are not well set up for a launch with a hundred+ objects. It looks like a year later, 43822 still shows up as Object BS, and there are several other equally unidentified objects: Object X (43779), Object BE (43810), and others. ...

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

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 ...

3

"The Rasperry Pi" is not space worthy in general. It depends on the model. RPis are built based on various chips. The RPi B+, for example, got a LAN9514 which is qualified for an operating temperature range of 0°-70°C, so it's not exactly space worthy unless you make sure to have an adapted operating environment in the cubesat. It's also not radiation ...

3

As you want to apply Stefan-Boltzmann, I will assume that you are interested in vacuum heat and radiation dynamics. As some comments have pointed out, at 140 km, interactions with the atmosphere would be very significant or dominant. That doesn't quite look like what you are after though, so I will completely ignore the atmosphere. For a starting point, let'...

3

If you conduct a loads analysis of both your end and the deployer and can prove that you still have adequate factors of safety in your design then getting a waiver should not be terrible. It's not unusual for a few waivers to be considered in a submission, but it varies a lot by dispenser vendor and launch provider in terms of how hard they are to approve. ...

3

The key consideration in Kelso's comments is that many of these satellites end up DoA, so you cannot rely on the satellite helping you in any way. Thus we are left with the need for passive methods to identify these dead satellites. The generally proposed concept is to have something on the satellite that makes it brighter to RADAR, such as reflectors This ...

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

@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 ...

2

There are potentially many forms of oscillation, all of which would require some form of damping. Any offset from straight is a higher energy state, and the system won't die down without some damping. There is however already a natural form of damping. The extension and contracting of the tether will damp some of that energy. Its worth noting that that won't ...

2

I second most of what @mefitico said in his excellent answer. Most CubeSat operators even universities will not permit you to operate their satellite. It is a valuable asset, and they don't want anyone just playing with it. Not to mention, often their licenses (e.g. NOAA) has significant restrictions on how they must operate their satellite. You can ...

2

Among Quantitative Feedback Theory and H infinity, which one is preferred for robust control of satellites esp. small satellites? And why? AFAIK Neither. First, you should define what you mean by "small satellite", the definition can vary between 30kg to 300kg. Second, in a small satellite, panels are generally mounted over faces rather than on deployable ...

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 ...

1

Recently in an interview with Micheal Sheetz, Peter Beck mentioned that the Electron “We actually showed that we could not only get to the moon, but we can do near-interplanetary stuff. We can go to Venus, we can go to Mars,” Beck said. Then in an interview with Everyday Astronaut, he said; "we can even get 20 odd kilograms to Venus" Note: The ...

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