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Small Satellites - Science topic

Small Satellites are a discussion group for researches interested in small satellite missions and technologies. Small spacecraft are satellites ranging in mass from a few hundred grams to under 100 kg and including the popular CubeSat platform.
Questions related to Small Satellites
Gustavo Diniz
Gustavo Diniz
  • asked a question related to Small Satellites
Is there a known origin for the satellite peaks of the 3d Ag XPS spectra?
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5 answers
  • 3 Jan 2025
The XPS spectra of 3d Ag exhibit two characteristic peaks at binding energies around 367 eV and 373 eV. However, it also reveals two small satellite peaks near these characteristic peaks. Is the origin of these peaks known?
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  • 9 Jan 2025
Answer
Jürgen Weippert thanks for the references! Yes, I am familiar with shake-up effect, but still these references were very helpful. Thanks again!
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Chandler Timm Cagmat Doloriel
Chandler Timm Cagmat Doloriel
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What are the trends and problems in on-board image processing for small satellites?
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4 answers
  • 18 Oct 2020
I'm starting a master's research about on-board image processing for small satellites but struggling to find a niche or problem to solve or discuss. I've read less than 15 articles about related works and would hopefully find one nice topic to pursue if I continue reading, but I just want to ask some senior researchers in this field what would they recommend.
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  • 21 Oct 2020
Answer
1- Various large smallsat constellations in low Earth orbit (LEO)
LEO has been commercially active in both broadband and imaging constellations of 100 satellites or more. This scenario takes mainly into account "mega-constellations" of broadband, providing a low latency to accessible global broadband Internet.
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2- Smalls with Larger Remote Sensing Satellites
In this scenario a increasing number of countries have close parallel access to technology with large satellites in distant context , given the remote sensing capabilities that are available commercially and beyond the United States.
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3- Insecure for LEO Satellite Operation
In this scenario a increasing number of countries have close parallel access to technology with large satellites in distant context , given the remote sensing capabilities that are available commercially and beyond the United States.
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4- On the Space Maintenance, Assembly & Development
In these circumstances, many persistent LEO and GEO platforms for on-orbit operation, assembly and development (OSAM) are used by governments and the private sector.
As large satellites become the standard for competitive and host payload platforms, the satellite industry is versatile in designing , constructing and utilizing satellites that best fit a given application. drives the perception of profitability and consequently injection of funding and talent into other drivers, including the development of new technology, low-cost approaches, and infrastructure.
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5- Market Demand
-- The most important technology for the four scenarios examined comprises optical imagery, radio frequency interference (RFI), spectrum use, small platform optical communication, and propulsion system miniaturization.
-- Low cost approaches to development , implementation, and robotics and alternative business models, such as modularity and standardization are included. are included.
-- Professional practice of infrastructure include space awareness technologies and systems (SSA), ground stations networks and space relays, and low cost ground antennas and terminals. Infrastructure drivers include
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6- Space Access
The fact that the four scenarios can be realised in the interim is driven
by the cost of their launch as well as the availability of reliable launch options.
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7- Alternatives to Compete
Smallsats may either render or ignore the relative value proposition for smellsats of alternatives such as terrestrial and airborne platforms and gradual and advanced developments in large satellites.
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8- Government Policies
The spectrum allocation policies of governments; RFI; protectionism/ mercantilism; debris mitigation; on-orbit regulation; and the management
of space traffic drive the private sector 's involvement in the smallsat ecosystem, both positive and negative.
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Giulio Santori
Giulio Santori
  • asked a question related to Small Satellites
Are you working also on active cryogenic systems?
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4 answers
  • 4 May 2017
Hi, my group has just started working on active cryogenic system for small satellites. Your solution can be very valuable to make our system working.
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  • 31 Dec 2017
Answer
I mean a fluid loop working on the condenser of a active cryogenic cooler.
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Muhammad Mahtab
Muhammad Mahtab
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Phasing maneuvers for a micro satellite constellation?
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3 answers
  • 20 Mar 2017
How to find the delta V for phasing maneuvers of a micro satellite constellation in a circular LEO? I have found deltaV using Hohmann transfer but the value is too large for the cold gas propulsion system of small satellites to handle.
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  • 20 Mar 2017
Answer
Hi do not have a reference of the impulsive case, but you will find attached a paper describing what happels in the low-thrust case. The formulas giving the natural evolution of the right ascension of the ascending node are given in this paper.
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Sriram Hariharan
Sriram Hariharan
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What are the important things that we have to consider after designing a scientific payload for a CubeSat?
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3 answers
  • 6 Sept 2016
Hello researchers, 
I am in halfway of designing a scientific payload for 1U CubeSat, sometimes I'll ask myself what are the points that I have to consider in terms of mechanical & electrical interface of CubeSat. 
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  • 7 Sept 2016
Answer
Thanks for your inputs @ David Bolton & Srinivasan Munisamy 
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Waqar Ali Shah
Waqar Ali Shah
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Coatings/Paints for ESD protection for Patch Antenna Radome in Space ?
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2 answers
  • 2 May 2016
am designing a Patch Antenna to be used on a small satellite in LEO orbit, For protection i am using a Delrin as a Radome of (75x75x3)mm dimensions. As delrin is an insulator it is susceptible to charge storage, Can you guide me as to what sort of material/coating/paint should i use for ESD protection without affecting my Radiation, as most of the Paints/coatings available for ESD have high conductivity and as per my understanding they are not microwave transparent.
Also for the size mentioned above at LEO orbit is it necessary to cater for ESD, The Delrin is fixed to the satellite body with eight screws.
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  • 5 May 2016
Answer
ESD should not be an issue in LEO.  The ionospheric plasma will prevent charge buildup unless the voltage is impressed onto a conductor by a power source.   That won't be the case for Delrin, a good insulator.  You may require a coating with the proper solar absorptivity and emittance to control the thermal situation.  Also, if in LEO an extended period of time the atomic oxygen environment in LEO is very chemically reactive.  An inorganic thermal control coating may be used.  These are available in industry.
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Mazhar Zia
Mazhar Zia
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How to decide the solar sail size for the cubesat?
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3 answers
  • 9 Mar 2016
Need a calculation method for it.
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  • 7 Apr 2016
Answer
The dimensions for a solar sail rather depend on what the sail is to be used for. In sailcraft built to date (IKAROS, NanoSail, LightSail), the purpose was primarily demonstrating stowage and deployment of a sail, and so size was chosen to be whatever was convenient for the stowage and deployment method, given the spacecraft bus size and design. (Don't get me started on how fundamentally useless it is to test-fly a stowage and deployment method that works for large mass:area ratios, but doesn't scale to sufficiently small ratios!)
For future operational solar sail missions, the sail size will have to be large enough to produce a large enough spacecraft acceleration, for whatever mission the spacecraft is meant to carry out. While there are a few useful missions that can be done with relatively small sails (e.g., NOAA's proposed GEOStorm mission), most require a mass:area ratio of 20 grams/m^2 or less, preferably 10 grams/m^2 or less, in order to be able to produce sufficient thrust. So, if you have (say) a 6U cubesat that can have a maximum total mass of (say) 8 kg, you'd want to carry a sail with an area of at least 400 m^2, preferably 800 m^2.
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Ali Danladi
Ali Danladi
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Space Power Systems: Design of a power system for small satellites - where to start and what are the essentials?
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8 answers
  • 10 Jan 2016
Space Power Systems: Design of a power system for small satellites - where to start and what are the essentials?
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  • 23 Jan 2016
Answer
This paper might be useful. It is the power system design document of our satellite.
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Derek Giuliana
Derek Giuliana
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How can I establish good 4T1 tumors in-vivo?
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8 answers
  • 5 Jun 2015
I'm growing 4T1 cells in mice. I'm implanting two contralateral tumors per mouse. I'm having a hard time getting the tumors to grow symmetrically. I understand they won't all be perfect, but I'm getting a lot of shapes that are difficult to caliper, or I'll have tumors with small satellite tumors right next to them.  With 2 tumors on 1 mouse, its hard to get enough mice to enroll in study.
I'm implanting 1 x 10^5 cells in 100 uL volumes. I draw the cells up into the syringe in an 18 g needle, and I implant the cells using a 25 g needle. I slowly inject the tumors on the flank and slowly remove the syringe. The cells are being implanted using serum free media. 
Should I use a smaller gauge (27g) needle to implant? Should I move my implant site up to the shoulder? Should I switch to PBS instead of media?
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  • 10 Jun 2015
Answer
Hi,
You can inject 4T1 cells from 5x103 to 1x105 in the up or low fat pad with volume 30ul to 50ul in Balb/c mice.  Then you can have lung metastasis and larger spleen ( 3-4 time weight (g) than normal mouse''s spleen.
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Susie Cumberland
Susie Cumberland
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What would you define a small satellite as?
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13 answers
  • 25 Mar 2015
I'm doing a project on optical communications between small satellites, however, I feel the general term given by Wertz of up to 500kg/1000lbs is quite vague and seems somewhat unnecessarily large. Using the http://satellitedebris.net/Database/UCSDB.php I found that out of the 1,000 odd satellites listed 568 had civil and/or commerical users and the mass ranged from 0.8kg to 6,910kg. 145 of those satellites were under 500kg, but, it seemed to jump to 689kg and above, leaving no medium/middle sized satellites. I would therefore, suggest saying less than 300kg. Additionally, Straub, J(2015) mentioned in his article In Search of Standards for the Operation of Small Satellites that only 14% of the university Cubesats were greater than 40kg. It just seems quite out of proportion to the advancements we have today to say 500kg is small.
Do you agree? Disagree? What is your opinion of this?
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  • 10 Apr 2015
Answer
Susie, to your original comment, "It just seems quite out of proportion to the advancements we have today to say 500kg is small" -- small is relative.
Current geosynchronous communications satellites are pushing 7000kg; by comparison, 500kg is pretty small. What we call "small" is also a reflection of how satellites are launched -- and the <500kg satellites are typically going up on smaller launch vehicles, or as secondary payloads.
It's also a reflection of relative cost -- small sat missions are generally much less expensive than larger ones (partly, but not entirely, driven by the launch cost.)
By comparison to nanosats (such as CubeSats) 500kg seems huge... but to those looking from the other end of the range, 500kg is not so large. Ultimately, the number used is a bit arbitrary. 180kg, for example, comes out of the max mass allowed for an ESPA-compatible secondary payload. 500kg is just a convenient round number.
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Elham Javadifard
Elham Javadifard
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What satellites and sensors are in the atmosphere from 2010 onwards?
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4 answers
  • 27 Feb 2014
see above
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  • 9 Oct 2014
Answer
Here are two new links, the second one is updated every 6 month.
http://www.oosa.unvienna.org/oosa/en/SORegister/index.html
http://www.ucsusa.org/nuclear_weapons_and_global_security/solutions/space-weapons/ucs-satellite-database.html#.VDZiKRZPJl4
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Paul F Wren
Paul F Wren
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Is anyone aware of a project building a 0.5U CubeSat?
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6 answers
  • 10 Sept 2014
Multiple suppliers of off-the-shelf CubeSat hardware sell side panels for 0.5U CubeSats, but I have not encountered anyone actually building and flying one.  Has anyone else?
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  • 15 Sept 2014
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I only know of CubeSat projects which use some combination of whole and half unit structures. For example, a FIREBIRD is a 1.5U CubeSat. This is generally how 0.5 U structures are used.I am aware of a design project to dock two identical 0.5U CubeSats with one another:
https://sa.catapult.org.uk/documents/2154681/6722800/CubeSatFinal+proposal3.pdf/3d36c654-7ba3-4f49-b0da-8715275fb358
I think a 0.5U CubeSat may be difficult to use unless it is being designed as an engineering exercise. A structure that small will most likely eliminate the possibility of certaing subsystems like attitude determination and control, which may result in a poor communications link. 
Will there be a payload or is there any room after power, on-board computer, thermal control (heaters)?  If a CubeSat does not have a payload, then what is it's purpose?
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Jagalingam P
Jagalingam P
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What is the need of carrying PAN Senor in satellite?
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4 answers
  • 12 Aug 2014
All satellites carry both PAN and MS sensors. PAN with high resolution(Spectral less) and MS with Spectral Rich (low spatial resolution). To improve the resolution of MS image, Pan-sharpening techniques has been developed. But My question is instead of carrying PAN sensor, why can't we calibrate the MS Sensor to acquire both spectral and spatial rich information in single image?
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  • 15 Aug 2014
Answer
To answer your question you should understand why PAN image has high spatial resolution and why hyperspetral sensor provide high spectral resolution image:
1. PAN image is acquired in 1 wide band in VIS spectral region, ex: LANDSAT 8 PAN band has wavelength of 0.50 - 0.68 µm. In such a wide wavelength, the radiance reflected by ground area is great enough to allow the sensor detect reflected radiance from small area, that mean it can provide high spatial resolution image.
2. In case of hyperspectral sensor, in order to get high spectral information it is designed to detect reflected radiance in narrow band, that means the reflected energy is also divided into smaller portions. This leads the detectors cannot detect the reflected radiance from small ground area because it is too small to be sensed (small area, small reflected energy), or if possible the sensor should has very high sensitivity, or has to be mounted on low orbit platform (e.g. smaller swath width).
But building such a sensor is challenging and costly. Therefore, if you want an image with rich spatial information you have to sacrifice the spectral information and vice versa.
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Mary Phillips
Mary Phillips
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Can anyone recommend a simple experiment for a student CubeSat Challenge?
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3 answers
  • 21 Oct 2013
CubeSat are 10cmX10cmX10 cm to be flown in space. Here is the website http://www.nasa.gov/directorates/heo/home/CubeSats_initiative.html#.UmUvKBAgq8A
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  • 31 Oct 2013
Answer
Well, it depends on your interests and budget. Nevertheless, my recommendation is a very small Geiger counter sold by Sparkfun (about 150 US dollars) that will allow you to learn about radiation belts.
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