View source for Small satellite

{{short description|Satellites of low mass and size, usually under 1200 kg}}
{{For|the DNA sequence|Microsatellite}}
[[File:Estcube-1 2012-12-27.jpg|thumb|[[ESTCube-1]] 1U [[CubeSat]] ]]
A '''small satellite''', '''miniaturized satellite''', or '''smallsat''' is a [[satellite]] of low mass and size, usually under {{convert|1200|kg|abbr=on}}.<ref name=brycesmall>{{cite web |url=https://brycetech.com/reports/report-documents/Bryce_Smallsats_2020.pdf |title=Smallsats by the Numbers |date=January 1, 2020 |website=brycetech.com }}</ref> While all such satellites can be referred to as "small", different classifications are used to categorize them based on [[mass]]. Satellites can be built small to reduce the large economic cost of [[launch vehicle]]s and the costs associated with construction.  Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, [[Satellite#Applications|gathering of scientific data]] and [[radio relay]].  Technical challenges in the construction of small satellites may include the lack of sufficient [[power storage]] or of room for a [[spacecraft propulsion|propulsion system]].

== Rationales ==
{| class="wikitable floatright"
!|Group name<ref name=brycesmall/>
!|Mass (kg)
|-
||Extra Heavy satellite
||> 7,000
|-
||Heavy satellite
||5,001 to 7,000 
|-
||Large satellite
||4,201 to 5,000
|-
||Intermediate satellite
||2,501 to 4,200
|-
||Medium satellite
||1,201 to 2,500
|-
||Small satellite
||601 to 1,200
|-
||[[#Minisatellites|Mini satellite]]
||201 to 600
|-
||[[#Microsatellites|Micro satellite]]
||11 to 200
|-
||[[#Nanosatellites|Nano satellite]]
||1.1 to 10
|-
||[[#Picosatellites|Pico satellite]]
||0.1 to 1
|-
||[[#Femtosatellites|Femto satellite]]
||<0.1
|}

One rationale for miniaturizing satellites is to reduce the cost; heavier satellites require larger rockets with greater thrust that also have greater cost to finance. In contrast, smaller and lighter satellites require smaller and cheaper launch vehicles and can sometimes be launched in multiples. They can also be launched 'piggyback', using excess capacity on larger launch vehicles. Miniaturized satellites allow for cheaper designs and ease of mass production.

Another major reason for developing small satellites is the opportunity to enable missions that a larger satellite could not accomplish, such as:
* Constellations for low data rate communications
* Using formations to gather data from multiple points
* In-orbit inspection of larger satellites
* University-related research
* Testing or qualifying new hardware before using it on a more expensive spacecraft

== History ==
The [[nanosatellite]] and [[microsatellite (spaceflight)|microsatellite]] segments of the satellite launch industry have been growing rapidly in the 2010s. Development activity in the {{convert|1|-|50|kg|abbr=on}} range has been significantly exceeding that in the {{convert|50|-|100|kg|abbr=on}} range.<ref name=swma2014/>

In the {{nowrap|1–50 kg}} range alone, fewer than 15 satellites were launched annually in 2000 to 2005, 34 in 2006, then fewer than 30 launches annually during 2007 to 2011.  This rose to 34 launched in 2012 and 92 launched in 2013.<ref name=swma2014>{{cite report |title=2014 Nano/Microsatellite Market Assessment |date=January 2014 |series=annual market assessment series |page=18 |url=http://www.sei.aero/eng/papers/uploads/archive/SpaceWorks_Nano_Microsatellite_Market_Assessment_January_2014.pdf |access-date=18 February 2014 |publisher=SEI |location=Atlanta, Georgia |url-status=live |archive-url=https://web.archive.org/web/20140222211907/http://www.sei.aero/eng/papers/uploads/archive/SpaceWorks_Nano_Microsatellite_Market_Assessment_January_2014.pdf |archive-date=22 February 2014}}</ref>

European analyst Euroconsult projects more than 500 smallsats being launched in  2015–2019 with a market value estimated at {{USD|7.4 billion}}.<ref name=pa20150302/>

By mid-2015, many more launch options had become available for smallsats, and rides as [[secondary payload]]s had become both greater in quantity and easier to schedule on shorter notice.<ref name=sn20150612>{{cite news |last1=Foust |first1=Jeff |title=Smallsat Developers Enjoy Growth In Launch Options |url=http://spacenews.com/smallsat-developers-enjoy-growth-in-launch-options/ |access-date=13 June 2015 |work=Space News |date=12 June 2015}}</ref>

In a surprising turn of events, the [[U.S. Department of Defense]], which had for decades procured heavy satellites on decade-long procurement cycles, is making a transition to smallsats in the 2020s. The office of space acquisition and integration said in January 2023 that "the era of massive satellites needs to be in the rear view mirror for the Department of Defense"<ref name=sn20230124/> with small satellites being procured for DoD needs in all orbital regimes, regardless of "whether it's [[Low Earth orbit|LEO]] [[Medium Earth orbit|MEO]] or [[Geosynchronous equatorial orbit|GEO]]" while aiming for procurements in under three years.<ref name=sn20230124/>  The smaller satellites are deemed to be harder for an enemy to target, as well as providing more resilience through redundancy in the design of a large [[decentralization|distributed network]] of [[Satellite constellation|satellite assets]].<ref name=sn20230124>{{cite news |title=Space Force not buying large satellites for the foreseeable future |url=https://spacenews.com/space-force-not-buying-large-satellites-for-the-foreseeable-future/ |last=Erwin|first=Sandra |work=SpaceNews |date=24 January 2023 |access-date=25 January 2023 }}</ref>

In 2021, the first [[autonomous nanosatellites]], part of the  Adelis-SAMSON mission, designed and developed by the [[Technion – Israel Institute of Technology|Technion]] and Rafael in [[Israel]] were launched into space.<ref>{{Cite web |last=David |first=Ricky Ben |date=2021-03-22 |title=In First, 3 Israeli Nanosatellites Launch Into Space For Geolocation Mission |url=https://nocamels.com/2021/03/3-israeli-nanosatellites-space-mission/ |access-date=2024-06-25 |website=NoCamels |language=en-US}}</ref> In 2023, SpaceX launched a 20cm quantum communication nano satellite developed by the [[Tel Aviv University]], it is the world's first quantum communication satellite.<ref name=":0">{{Cite news |date=4 January 2023 |title=Israeli quantum communication nanosatellite launched into orbit by SpaceX rocket |url=https://www.timesofisrael.com/israeli-quantum-communication-nanosatellite-launched-into-orbit-by-spacex-rocket/}}</ref> TAU's nanosatellite is designed to form a quantum communication network as well as communicate with Earth through an optical ground station.<ref name=":0" /><ref>{{Cite web|url=https://www.jns.org/israeli-nanosatellite-a-breakthrough-in-quantum-communications/|title=Israeli nanosatellite a breakthrough in quantum communications - JNS.org}}</ref>

== Classification groups ==
[[File:Space Technology 5 on payload structure.jpg|thumb|Three microsatellites of [[Space Technology 5]]]]

=== Small satellites ===
The term "small satellite",<ref name=swma2014/> or sometimes "minisatellite", often refers to an artificial satellite with a [[wet mass]] (including fuel) between {{convert|100|and|500|kg|abbr=on}},<ref name=did20120630/><ref name=tristancho2010/> but in other usage has come to mean any satellite under {{convert|500|kg|abbr=on}}.<ref name=pa20150302>{{cite news |last1=Messier |first1=Doug |title=Euroconsult Sees Large Market for Smallsats |url=http://www.parabolicarc.com/2015/03/02/euroconsult-sees-large-market-smallsats/ |access-date=8 March 2015 |work=Parabolic Arc |date=2 March 2015 |url-status=live |archive-url=https://web.archive.org/web/20150305183555/http://www.parabolicarc.com/2015/03/02/euroconsult-sees-large-market-smallsats/ |archive-date=5 March 2015}}</ref>

Small satellite examples{{according to whom|date=March 2021}} include [[Demeter (satellite)|Demeter]], [[Essaim (satellite)|Essaim]], [[Parasol (satellite)|Parasol]], [[Picard (satellite)|Picard]], [[MICROSCOPE (satellite)|MICROSCOPE]], [[TARANIS]], [[ELISA (satellite)|ELISA]], [[SSOT (satellite)|SSOT]], [[SMART-1]], [[Spirale|Spirale-A and -B]], and [[Starlink]] satellites.{{citation needed|date=March 2021}}

==== Small satellite launch vehicle ====
Although smallsats have traditionally been launched as secondary payloads on larger launch vehicles, a number of companies began development of launch vehicles specifically targeted at the smallsat market. In particular, with larger numbers of smallsats flying, the secondary payload paradigm does not provide the specificity required for many small satellites that have unique orbital and launch-timing requirements.<ref name=sn20130812/>

Some USA-based private companies that at some point in time have launched smallsat launch vehicles commercially:
*[[Orbital Sciences Corporation]]'s [[Pegasus (rocket)]]<ref>{{Cite web |title=Pegasus XL Launch Vehicle {{!}} National Air and Space Museum |url=https://airandspace.si.edu/collection-objects/launch-vehicle-pegasus-xl-orbital-sciences-corporation/nasm_A20040262000 |access-date=2024-10-08 |website=airandspace.si.edu |language=en}}</ref>
*[[Rocket Lab]]'s [[Electron (rocket)|Electron]] (300&nbsp;kg)<ref>{{Cite web|url=https://www.rocketlabusa.com/launch/electron/|title=Rocket Lab Electron (rocket)|date=2022-07-31|website=Rocket Lab Electron (rocket)|access-date=2022-07-31}}</ref>
*[[Virgin Orbit]]'s [[LauncherOne]] (500&nbsp;kg)<ref>{{Cite web|date=2019-07-29|title=Virgin Orbit Service Guide|url=https://virginorbit.com/wp-content/uploads/2018/11/Virgin-Orbit-Service-Guide.pdf|access-date=2019-07-29|website=Virgin Orbit Service Guide|archive-date=19 March 2019|archive-url=https://web.archive.org/web/20190319211045/https://virginorbit.com/wp-content/uploads/2018/11/Virgin-Orbit-Service-Guide.pdf|url-status=dead}}</ref>
*[[Astra, Inc.|Astra]]'s [[Rockets by Astra|Rocket 3.3]] (100&nbsp;kg)<ref>{{Cite web|url=https://astra.com/news/astra-reaches-orbit/|title=Astra Reaches Orbit |date=2021-11-22|website=Astra (Private Space Company)|access-date=2021-12-07}}</ref>
*[[Firefly Aerospace]]'s [[Firefly Alpha]]<ref>{{Cite web |title=Alpha Launch Vehicle |url=https://fireflyspace.com/alpha/ |access-date=2024-10-08 |website=Firefly Aerospace |language=en-US}}</ref>

=== Microsatellites ===
The term "microsatellite" or "microsat" is usually applied to the name of an artificial satellite with a wet mass between {{convert|10|and|100|kg|abbr=on}}.<ref name=swma2014/><ref name=did20120630>{{cite news |title=Small Is Beautiful: US Military Explores Use of Microsatellites |url=http://www.defenseindustrydaily.com/Small-Is-Beautiful-US-Military-Explores-Use-of-Microsatellites-06720/ |access-date=12 December 2012 |newspaper=Defense Industry Daily |date=30 June 2011 |url-status=live |archive-url=https://web.archive.org/web/20121213014300/http://www.defenseindustrydaily.com/Small-Is-Beautiful-US-Military-Explores-Use-of-Microsatellites-06720/ |archive-date=13 December 2012}}</ref><ref name=tristancho2010/> However, this is not an official convention and sometimes those terms can refer to satellites larger than that, or smaller than that (e.g., {{convert|1|-|50|kg|abbr=on}}).<ref name=swma2014/> Sometimes, designs or proposed designs from some satellites of these types have microsatellites [[Satellite constellation|working together]] or in a [[Fractionated spacecraft|formation]].<ref name=nbc20150604>{{cite news |last1=Boyle |first1=Alan |title=How SpaceX Plans to Test Its Satellite Internet Service in 2016 |url=http://www.nbcnews.com/science/space/how-spacex-plans-test-its-satellite-internet-service-2016-n370196 |access-date=5 June 2015 |work=NBC News |date=4 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150605074222/http://www.nbcnews.com/science/space/how-spacex-plans-test-its-satellite-internet-service-2016-n370196 |archive-date=5 June 2015}}</ref> The generic term "small satellite" or "smallsat" is also sometimes used,<ref name=nsj20120711/> as is "satlet".<ref name=sn20140321>{{cite news |last=Gruss |first=Mike |title=DARPA Space Budget Increase Includes $27M for Spaceplane |url=http://www.spacenews.com/article/military-space/39938darpa-space-budget-increase-includes-27m-for-spaceplane |archive-url=https://archive.today/20140324034149/http://www.spacenews.com/article/military-space/39938darpa-space-budget-increase-includes-27m-for-spaceplane |url-status=dead |archive-date=24 March 2014 |access-date=24 March 2014 |newspaper=Space News |date=21 March 2014}}</ref>

Examples: [[Astrid (satellite)|Astrid-1]] and Astrid-2,<ref>{{Cite journal |last1=Merayo |first1=J.M.G. |last2=Brauer |first2=P. |last3=Primdahl |first3=F. |last4=Joergensen |first4=P.S. |last5=Risbo |first5=T. |last6=Cain |first6=J. |date=April 2002 |title=The spinning Astrid-2 satellite used for modeling the Earth's main magnetic field |url=https://ieeexplore.ieee.org/document/1006371 |journal=IEEE Transactions on Geoscience and Remote Sensing |volume=40 |issue=4 |pages=898–909 |doi=10.1109/TGRS.2002.1006371 |bibcode=2002ITGRS..40..898M |s2cid=261967136 |issn=1558-0644}}</ref> as well as the set of satellites currently announced for ''LauncherOne'' (below)<ref name=nsj20120711/>

In 2018, the two [[Mars Cube One]] microsats—massing just {{cvt|13.5|kg}} each—became the first CubeSats to leave Earth orbit for use in interplanetary space.  They flew on their way to Mars alongside the successful Mars ''[[InSight]]'' [[Mars lander|lander]] mission.<ref name=nyt2019318>{{cite news |last=Stirone|first=Shannon |title=Space Is Very Big. Some of Its New Explorers Will Be Tiny. - The success of NASA's MarCO mission means that so-called cubesats likely will travel to distant reaches of our solar system. |url=https://www.nytimes.com/2019/03/18/science/cubesats-marco-mars.html |date=18 March 2019 |work=[[The New York Times]] |access-date=21 April 2019 }}</ref>
The two microsats accomplished a [[Flyby (spaceflight)|flyby]] of Mars in November 2018, and both continued communicating with ground stations on Earth through late December.  Both went silent by early January 2019.<ref name=jpl20190204>{{cite news |last1=Good|first1=Andrew |last2=Wendel|first2=JoAnna |url=https://www.jpl.nasa.gov/news/news.php?feature=7327 |title=Beyond Mars, the Mini MarCO Spacecraft Fall Silent |work=[[Jet Propulsion Laboratory]] |publisher=[[NASA]] |date=4 February 2019 |access-date=5 February 2019}}</ref>

==== Microsatellite launch vehicle ====
A number of [[private spaceflight|commercial]] and military-contractor companies are currently developing '''microsatellite launch vehicles''' to perform the increasingly [[orbital trajectory|targeted]] launch requirements of microsatellites.  While microsatellites have been carried to space for many years as secondary payloads aboard larger [[launch vehicle|launchers]], the secondary payload paradigm does not provide the specificity required for many increasingly sophisticated small satellites that have unique orbital and launch-timing requirements.<ref name=sn20130812>{{cite news |last=Werner |first=Debra |title=Small Satellites & Small Launchers: Rocket Builders Scramble To Capture Growing Microsat Market |url=https://spacenews.com/36741small-satellites-small-launchers-rocket-builders-scramble-to-capture/ |access-date=13 March 2021 |newspaper=Space News |date=12 August 2013}}</ref>

In July 2012, [[Virgin Orbit]] announced [[LauncherOne]], an [[orbital launch vehicle]] designed to launch "smallsat" primary [[Payload (air and space craft)|payloads]] of {{convert|100|kg|abbr=on}} into [[low Earth orbit]], with launches projected to begin in 2016.  Several commercial customers have already contracted for launches, including [[GeoOptics]], [[Skybox Imaging]], [[Spaceflight Industries]], and [[Planetary Resources]].  Both [[Surrey Satellite Technology]] and [[Sierra Nevada Corporation|Sierra Nevada Space Systems]] are developing [[satellite bus]]es "optimized to the design of LauncherOne".<ref name=nsj20120711>{{cite news |title=Virgin Galactic relaunches its smallsat launch business |url=http://www.newspacejournal.com/2012/07/11/virgin-galactic-relaunches-its-smallsat-launch-business/ |access-date=11 July 2012 |newspaper=NewSpace Journal |date=12 July 2012 |url-status=live |archive-url=https://web.archive.org/web/20120715235055/http://www.newspacejournal.com/2012/07/11/virgin-galactic-relaunches-its-smallsat-launch-business/ |archive-date=15 July 2012}}</ref>  Virgin Orbit has been working on the LauncherOne concept since late 2008,<ref name=fgh20081209>[http://www.flightglobal.com/blogs/hyperbola/2008/12/exclusive-virgin-galactic-unve.html EXCLUSIVE: Virgin Galactic unveils LauncherOne name!] {{webarchive|url=https://web.archive.org/web/20130514165558/http://www.flightglobal.com/blogs/hyperbola/2008/12/exclusive-virgin-galactic-unve.html |date=14 May 2013 }}, Rob Coppinger, Flightglobal Hyperbola, 9 December 2008</ref> and {{asof|2015|lc=y}}, is making it a larger part of Virgin's core business plan as the Virgin human spaceflight program has experienced multiple delays and a fatal accident in 2014.<ref name=telegraph20150822>{{cite news |last1=Burn-Callander |first1=Rebecca |title=Virgin Galactic boldly goes into small satellites, telling future astronauts 'you have to wait' |url=https://www.telegraph.co.uk/finance/newsbysector/industry/11816213/Virgin-Galactic-boldly-goes-into-small-satellites-telling-future-astronauts-you-have-to-wait.html |access-date=24 August 2015 |newspaper=UK Telegraph |date=22 August 2015 |url-status=live |archive-url=https://web.archive.org/web/20150824021720/http://www.telegraph.co.uk/finance/newsbysector/industry/11816213/Virgin-Galactic-boldly-goes-into-small-satellites-telling-future-astronauts-you-have-to-wait.html |archive-date=24 August 2015}}</ref>

In December 2012, [[DARPA]] announced that the [[Airborne Launch Assist Space Access]] program would provide the microsatellite rocket booster for the DARPA SeeMe program that intended to release a "[[Satellite constellation|constellation]] of 24 micro-satellites (~{{convert|20|kg|abbr=on}} range) each with 1-m imaging [[Satellite imagery|resolution]]."<ref name=nsw20121219>{{cite news |last=Lindsey |first=Clark |title=DARPA developing microsat constellation orbited with air-launch system |url=http://www.newspacewatch.com/articles/darpa-developing-microsat-constellation-orbited-with-air-launch-system.html |access-date=22 December 2012 |newspaper=NewSpace Watch |date=19 December 2012 |url-access=subscription|url-status=live |archive-url=https://web.archive.org/web/20130526224612/http://www.newspacewatch.com/articles/darpa-developing-microsat-constellation-orbited-with-air-launch-system.html |archive-date=26 May 2013}}</ref>  The program was cancelled in December 2015.<ref>{{cite news |url=http://spacenews.com/darpa-airborne-launcher-effort-falters/ |title=DARPA Scraps Plan To Launch Small Sats from F-15 Fighter Jet |work=SpaceNews |first=Mike |last=Gruss |date=30 November 2015}}</ref>

In April 2013, [[Garvey Spacecraft]] was awarded a {{US$|200,000}} contract to evolve their ''Prospector 18'' [[suborbital]] launch vehicle technology into an orbital nanosat launch vehicle capable of delivering a {{convert|10|kg|abbr=on}} payload into a {{convert|250|km|abbr=on}} orbit to an even-more-capable [[Modular rocket|clustered]] "20/450 Nano/Micro Satellite Launch Vehicle" (NMSLV) capable of delivering {{convert|20|kg|abbr=on}} payloads into {{convert|450|km|abbr=on}} [[low Earth orbit|circular orbits]].<ref name=pa20130404/>

The [[Boeing Small Launch Vehicle]] is an [[air launch to orbit|air-launched]] three-stage-to-orbit [[launch vehicle]] concept aimed to launch small payloads of {{convert|100|lb|kg|order=flip|abbr=on}} into low Earth orbit.  The program is proposed to drive down launch costs for U.S. military small satellites to as low as {{US$|300,000}} per launch ($7,000/kg) and, if the development program was funded, {{asof|2012|lc=y}} could be operational by 2020.<ref name=aw20120521>{{cite news |last=Norris |first=Guy |title=Boeing Unveils Air-Launched Space-Access Concept |url=http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_05_21_2012_p25-458597.xml&p=1 |access-date=23 May 2012 |newspaper=Aviation Week |date=21 May 2012 |url-status=live |archive-url=https://web.archive.org/web/20130326232014/http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2FAW_05_21_2012_p25-458597.xml&p=1 |archive-date=26 March 2013}}</ref>

The Swiss company [[Swiss Space Systems]] (S3) has announced plans in 2013 to develop a suborbital [[spaceplane]] named ''SOAR'' that would launch a microsat launch vehicle capable of putting a payload of up to {{convert|250|kg|abbr=on}} into low Earth orbit.<ref name=dp20131008>{{cite news |last=Painter |first=Kristen Leigh |title=Spaceport Colorado lands agreement with Swiss space company Read more: Spaceport Colorado lands agreement with Swiss space company |url=http://www.denverpost.com/business/ci_24261021/spaceport-colorado-lands-agreement-swiss-space-company |access-date=21 October 2013 |newspaper=The Denver Post |date=8 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131011013440/http://www.denverpost.com/business/ci_24261021/spaceport-colorado-lands-agreement-swiss-space-company |archive-date=11 October 2013}}</ref>

The Spanish company [[PLD Space]] born in 2011 with the objective of developing low cost launch vehicles called [[PLD Space#Miura 1|Miura 1]] and [[PLD Space#Miura 5|Miura 5]] with the capacity to place up to {{convert|150|kg|abbr=on}} into orbit.<ref name="yahoo">{{cite web|url=https://es.noticias.yahoo.com/blogs/astronomia-terricolas/pld-space--la-empresa-espa%C3%B1ola-camino-de-lanzar-sat%C3%A9lites-e-incluso-alcanzar-la-luna-133224289.html|title=PLD Space, la empresa española camino de lanzar satélites e incluso alcanzar la Luna|last1=Peláez|first1=Javier|website=Yahoo noticias|publisher=Yahoo|archive-url=https://web.archive.org/web/20160305210833/https://es.noticias.yahoo.com/blogs/astronomia-terricolas/pld-space--la-empresa-espa%C3%B1ola-camino-de-lanzar-sat%C3%A9lites-e-incluso-alcanzar-la-luna-133224289.html|archive-date=5 March 2016|url-status=live|access-date=19 April 2016}}</ref>

=== Nanosatellites ===
[[File:Nanosatellites yearly launches.svg|thumb|Launched nanosatellites as of December 2023<ref name="nanosats" />]]

The term "nanosatellite" or "nanosat" is applied to an artificial satellite with a [[mass ratio|wet mass]] between {{convert|1|and|10|kg|abbr=on}}.<ref name=swma2014/><ref name=did20120630/><ref name=tristancho2010/> Designs and proposed designs of these types may be launched individually, or they may have multiple nanosatellites working together or in formation, in which case, sometimes the term "satellite swarm"<ref name=verhoeven2011>{{cite journal |last=Verhoeven |first=C.J.M. |author2=Bentum, M.J. |author3=Monna, G.L.E. |author4=Rotteveel, J. |author5=Guo, J. |title=On the origin of satellite swarms |journal=Acta Astronautica |date=April–May 2011 |volume=68 |issue=7–8 |pages=1392–1395 |doi=10.1016/j.actaastro.2010.10.002 |bibcode=2011AcAau..68.1392V|url=http://doc.utwente.nl/68513/1/IAC-09_D1_1_6.pdf }}</ref> or "[[fractionated spacecraft]]" may be applied. Some designs require a larger "mother" satellite for communication with ground controllers or for launching and docking with nanosatellites. Over 2300 nanosatellites have been launched as of December 2023.<ref name="database">{{cite web |url=https://sites.google.com/a/slu.edu/swartwout/home/cubesat-database |title=CubeSat Database |website=sites.google.com |publisher=Saint Louis University |first=Michael A. |last=Swartwout |access-date=1 October 2018}}</ref><ref name="nanosats">{{cite web |title=Nanosatellite & CubeSat Database |first=Erik |last=Kulu |date=4 October 2020 |url=http://www.nanosats.eu/ |access-date=5 January 2024}}</ref>

A [[CubeSat]]<ref>{{cite news |title= NASA Venture Class procurement could nurture, ride small sat trend |date= 8 June 2015 |work=[[SpaceNews]] |url= http://spacenews.com/editorial-nasa-venture-class-procurement-could-nurture-ride-small-sat-trend/ |access-date=14 December 2020}}</ref> is a common type of nanosatellite,<ref name="nanosats"/> built in cube form based on multiples of 10&nbsp;cm × 10&nbsp;cm × 10&nbsp;cm, with a mass of no more than {{convert|1.33|kg}} per unit.<ref name=DesignSpecs>{{cite report |title=CubeSat Design Specification Rev. 13 |work=The CubeSat Program |publisher=[[California Polytechnic State University]] |date=20 February 2014 |url=https://static1.squarespace.com/static/5418c831e4b0fa4ecac1bacd/t/56e9b62337013b6c063a655a/1458157095454/cds_rev13_final2.pdf |access-date=14 December 2020}}</ref> The CubeSat concept was first developed in 1999 by a collaborative team of [[California Polytechnic State University]] and [[Stanford University]], and the specifications, for use by anyone planning to launch a CubeSat-style nanosatellite, are maintained by this group.<ref name=DesignSpecs/>

With continued advances in the [[Moore's law|miniaturization and capability increase of electronic technology]] and the use of [[satellite constellation]]s, nanosatellites are increasingly capable of performing commercial missions that previously required microsatellites.<ref name=tsitas2012/>
For example, a [[CubeSat|6U CubeSat]] standard has been proposed to enable a [[satellite constellation]] of thirty five {{convert|8|kg|abbr=on}} [[Earth-imaging satellite]]s to replace a constellation of five {{convert|156|kg|abbr=on}} [[RapidEye#Satellites|RapidEye]] Earth-imaging satellites, at the same mission cost, with significantly increased revisit times: every area of the globe can be imaged every 3.5 hours rather than the once per 24 hours with the RapidEye constellation. More rapid revisit times are a significant improvement for nations performing disaster response, which was the purpose of the RapidEye constellation. Additionally, the nanosat option would allow more nations to own their own satellite for off-peak (non-disaster) imaging data collection.<ref name=tsitas2012>{{cite journal |last=Tsitas |first=S. R. |author2=Kingston, J. |title=6U CubeSat commercial applications |journal=The Aeronautical Journal |date=February 2012 |volume=116 |issue=1176 |pages=189–198|doi=10.1017/S0001924000006692 |s2cid=113099378 }}</ref> As costs lower and production times shorten, nanosatellites are becoming increasingly feasible ventures for companies.<ref>{{cite news |url=https://nordic.businessinsider.com/why-self-organizing-companies-take-off-how-two-of-our-employees-got-our-firm-to-build-a-satellite--/ |title=Why self-organizing companies take off - How 2 employees at a Finnish tech firm invented and built a space program |work=Business Insider Nordic |first=Panu |last=Liira |date=13 February 2018 |access-date=5 August 2018 |archive-date=5 August 2018 |archive-url=https://web.archive.org/web/20180805030121/https://nordic.businessinsider.com/why-self-organizing-companies-take-off-how-two-of-our-employees-got-our-firm-to-build-a-satellite--/ |url-status=dead }}</ref>

Some examples of nanosatellites are the [[ExoCube (CP-10)]], [[ArduSat]], and SPROUT.<ref>{{cite web |url=https://directory.eoportal.org/web/eoportal/satellite-missions/s/sprout |title=SPROUT - Satellite Missions - eoPortal Directory |website=directory.eoportal.org |access-date=3 May 2018 |url-status=live |archive-url=https://web.archive.org/web/20160501182514/https://directory.eoportal.org/web/eoportal/satellite-missions/s/sprout |archive-date=1 May 2016}}</ref> Nanosatellite developers and manufacturers include [[EnduroSat]], [[GomSpace]], [[NanoAvionics]], NanoSpace, [[Spire Global|Spire]],<ref name=gaurd15>{{cite news |last=Barron |first=Rachel |title=Spire's Peter Platzer: the boss who never fires anyone |url=https://www.theguardian.com/sustainable-business/2015/apr/06/spire-worker-happiness-jobs-careers-fired-tech-employees |access-date=21 April 2016 |newspaper=The Guardian |date=6 April 2015 |url-status=live |archive-url=https://web.archive.org/web/20160428054305/http://www.theguardian.com/sustainable-business/2015/apr/06/spire-worker-happiness-jobs-careers-fired-tech-employees |archive-date=28 April 2016}}</ref> [[Surrey Satellite Technology]],<ref name=economist20140607/> [[NovaWurks]],<ref name=pa20131011>{{cite news |last=Messier |first=Doug |title=NovaWurks Awarded Contract for DARPA Phoenix Project |url=http://www.parabolicarc.com/2013/10/11/50313/ |access-date=13 October 2013 |newspaper=Parabolic Arc |date=11 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131013021727/http://www.parabolicarc.com/2013/10/11/50313/ |archive-date=13 October 2013}}</ref> [[Dauria Aerospace]],<ref name=vb20131009>{{cite news |last=Cheredar |first=Tom |title=Dauria Aerospace lands $20M to grow its earth-monitoring nano satellite platform |url=https://venturebeat.com/2013/10/09/dauria-aerospace-funding/ |access-date=13 October 2013 |newspaper=VentureBeat |date=9 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20131013020912/http://venturebeat.com/2013/10/09/dauria-aerospace-funding/ |archive-date=13 October 2013}}</ref> [[Planet Labs]]<ref name="economist20140607" /> and [[Reaktor (company)|Reaktor]].<ref>{{cite web |url=https://reaktorspace.com/ |title=Home - Reaktor Space Lab |website=Reaktor Space Lab |access-date=5 August 2018}}</ref>

==== Nanosat market ====
In the ten years of nanosat launches prior to 2014, only 75 nanosats were launched.<ref name="nanosats" /> Launch rates picked up substantially when in the three-month period from November 2013–January 2014 94 nanosats were launched.<ref name=economist20140607>{{cite news |title=Nanosats are go! |url=https://www.economist.com/news/technology-quarterly/21603240-small-satellites-taking-advantage-smartphones-and-other-consumer-technologies |access-date=12 June 2014 |work=Technology Quarterly Q2 2014 |publisher=The Economist |date=7 June 2014 |quote=On November 19th Orbital Sciences, an American company, launched a rocket from the Wallops Flight Facility in Virginia. It carried 29 satellites aloft and released them into low-Earth orbit, a record for a single mission. Thirty hours later, Kosmotras, a Russian joint-venture, carried 32 satellites into a similar orbit. Then, in January 2014, Orbital Sciences carried 33 satellites up to the International Space Station (ISS), where they were cast off a month later. |url-status=live |archive-url=https://web.archive.org/web/20140612022309/http://www.economist.com/news/technology-quarterly/21603240-small-satellites-taking-advantage-smartphones-and-other-consumer-technologies |archive-date=12 June 2014}}</ref>

One challenge of using nanosats has been the economic delivery of such small satellites to anywhere beyond [[low Earth orbit]]. By late 2014, proposals were being developed for larger spacecraft specifically designed to deliver swarms of nanosats to trajectories that are [[List_of_orbits#Special_classifications|beyond Earth orbit]] for applications such as exploring distant asteroids.<ref name=wired20141217>{{cite magazine |last1=Woo |first1=Marcus |title=Designing a Mothership to Deliver Swarms of Spacecraft to Asteroids |url=https://www.wired.com/2014/12/cubesat-mothership-space-asteroid-exploration/ |access-date=17 December 2014 |magazine=Wired |date=20 December 2014 |url-status=live |archive-url=https://web.archive.org/web/20141217134956/http://www.wired.com/2014/12/cubesat-mothership-space-asteroid-exploration/ |archive-date=17 December 2014}}</ref>

==== Nanosatellite launch vehicle ====
With the emergence of the technological advances of [[miniaturization]] and increased [[Financial capital|capital]] to support private spaceflight initiatives in the 2010s, several startups have been formed to pursue opportunities with developing a variety of small-payload Nanosatellite Launch Vehicle (NLV) technologies.

NLVs proposed or under development include:
* [[Virgin Orbit]] ''[[LauncherOne]]'' [[upper stage]], intended to be [[Air launch to orbit|air-launched]] from [[Scaled Composites White Knight Two|WhiteKnightTwo]] similar to how the [[SpaceShipTwo]] spaceplane is launched.<ref name=economist20140607/><ref name=bbc20120711>{{cite news |last=Amos |first=Jonathan |title=Richard Branson's Virgin Galactic to launch small satellites |url=https://www.bbc.co.uk/news/science-environment-18801180 |access-date=13 July 2012 |newspaper=BBC News |date=11 July 2012 |url-status=live |archive-url=https://web.archive.org/web/20120713034917/http://www.bbc.co.uk/news/science-environment-18801180 |archive-date=13 July 2012}}</ref>
* Ventions' Nanosat upper stage.<ref name=pa20120702>{{cite news |last=Messier |first=Doug |title=DARPA Awards 6 Small Airborne Launch Vehicle Contracts |url=http://www.parabolicarc.com/2012/07/02/darpa-awards-6-small-airborne-launch-vehicle-contracts/ |access-date=29 November 2012 |newspaper=Parabolic Arc |date=2 July 2012 |url-status=live |archive-url=https://web.archive.org/web/20120705033359/http://www.parabolicarc.com/2012/07/02/darpa-awards-6-small-airborne-launch-vehicle-contracts/ |archive-date=5 July 2012}}</ref>
* [[Nammo]]/[[Andøya Space Center|Andøya]] ''[[North Star (rocket family)|North Star]]'' ([[polar orbit]]-capable launcher for a {{convert|10|kg|abbr=on}} payload)<ref name=nsw20130128>{{cite news |last=Lindsey |first=Clark |title=North Star rocket family with hybrid propulsion |url=http://www.newspacewatch.com/articles/north-star-rocket-family-with-hybrid-propulsion-.html |access-date=28 January 2013 |newspaper=NewSpace Watch |date=28 January 2013 |url-access=subscription|url-status=live |archive-url=https://web.archive.org/web/20130620190153/http://www.newspacewatch.com/articles/north-star-rocket-family-with-hybrid-propulsion-.html |archive-date=20 June 2013}}</ref>
* {{asof|2013|04}}, [[Garvey Spacecraft]] (now [[Vector Launch]]) is evolving their ''Prospector 18'' suborbital launch vehicle technology into an orbital nanosat launch vehicle capable of delivering a {{convert|10|kg|abbr=on}} payload into a {{convert|250|km|abbr=on}} orbit.<ref name=pa20130404>{{cite news |last=Messier |first=Doug |title=Garvey Nanosat Launcher Selected for NASA SBIR Funding |url=http://www.parabolicarc.com/2013/04/04/garvey-nanosat-launcher-selected-for-nasa-sbir-funding/ |access-date=5 April 2013 |newspaper=Parabolic Arc |date=4 April 2013 |url-status=live |archive-url=https://web.archive.org/web/20130409141312/http://www.parabolicarc.com/2013/04/04/garvey-nanosat-launcher-selected-for-nasa-sbir-funding/ |archive-date=9 April 2013}}</ref>
* [[Generation Orbit]] is developing an air-launched rocket to deliver both nanosats and {{nowrap|sub-50 kg}} microsats to low Earth orbit.<ref name=economist20140607/>

Actual NS launches:
* [[NASA]] launched three satellites on 21 April 2013 based on smart phones. Two phones use the [[PhoneSat]] 1.0 specification and the third used a beta version of PhoneSat 2.0<ref>{{cite web |url=http://www.phonesat.org/index.php |title=PhoneSat - home |access-date=24 April 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130423000649/http://www.phonesat.org/index.php |archive-date=23 April 2013}}</ref>
* [[ISRO]] launched 14 nanosatellites on 22 June 2016, 2 for Indian universities and 12 for the United States under the [[Flock-2P]] program. This launch was performed during the [[PSLV-C34]] mission.
* [[ISRO]] launched 103 nanosatellites on 15 February 2017. This launch was performed during the [[PSLV-C37]] mission.<ref>{{Cite news |url=http://www.indiatvnews.com/news/india-countdown-begins-india-to-launch-record-104-satellites-on-single-rocket-368925 |title=ISRO sets new world record, successfully places 104 satellites into Earth's orbit |work=India TV News |date=15 February 2017 |access-date=15 February 2017 |url-status=live |archive-url=https://web.archive.org/web/20170215070009/http://www.indiatvnews.com/news/india-countdown-begins-india-to-launch-record-104-satellites-on-single-rocket-368925 |archive-date=15 February 2017}}</ref>

=== Picosatellites ===
The term "picosatellite" or "picosat" (not to be confused with the [[PicoSAT]] series of microsatellites) is usually applied to artificial satellites with a wet mass between {{convert|0.1|and|1|kg|abbr=on|sigfig=2}},<ref name=did20120630/><ref name=tristancho2010/> although it is sometimes used to refer to any satellite that is under 1&nbsp;kg in launch mass.<ref name=swma2014/> Again, designs and proposed designs of these types usually have multiple picosatellites working together or in formation (sometimes the term "swarm" is applied). Some designs require a larger "mother" satellite for communication with ground controllers or for launching and docking with picosatellites.

Picosatellites are emerging as a new alternative for [[Do it yourself|do-it-yourself]] kitbuilders. Picosatellites are currently commercially available across the full range of {{convert|0.1|-|1|kg|abbr=on|sigfig=2}}. Launch opportunities are now available for $12,000 to $18,000 for sub-1&nbsp;kg picosat payloads that are approximately the size of a soda can.<ref name=kk20121212>{{cite web |title=DIY Satellite Platforms |url=http://kk.org/cooltools/archives/7419 |publisher=KK Technium |access-date=12 December 2012 |url-status=live |archive-url=https://web.archive.org/web/20121213182216/http://kk.org/cooltools/archives/7419 |archive-date=13 December 2012|date=9 November 2012 }}</ref>

=== Femtosatellites ===
The term "femtosatellite" or "femtosat" is usually applied to artificial satellites with a wet mass below {{convert|100|g|abbr=on|sigfig=2}}.<ref name=swma2014/><ref name=did20120630/><ref name=tristancho2010>{{cite journal |last=Tristancho |first=Joshua |author2=Gutierrez, Jordi |title=Implementation of a femto-satellite and a mini-launcher |journal=Universitat Politecnica de Catalunya |year=2010 |page=3 |url=http://upcommons.upc.edu/pfc/bitstream/2099.1/9652/1/memoria.pdf |access-date=12 December 2012 |url-status=live |archive-url=https://web.archive.org/web/20130703080826/http://upcommons.upc.edu/pfc/bitstream/2099.1/9652/1/memoria.pdf |archive-date=3 July 2013}}</ref> Like picosatellites, some designs require a larger "mother" satellite for communication with ground controllers.

Three prototype "chip satellites" were launched to the [[ISS]] on {{OV|Endeavour}} on its [[STS-134|final mission]] in May 2011. They were attached to the ISS external platform [[Materials International Space Station Experiment]] (MISSE-8) for testing.<ref name=cc20110426>{{cite news | date = 16 May 2011 | title = Chip satellites -- designed to blow in the solar wind -- depart on Endeavour's final launch | author = Elizabeth Simpson | newspaper = [[Cornell Chronicle]] | access-date = 6 December 2012 | url = http://www.news.cornell.edu/stories/April11/endeavoursatellite.html | url-status = live | archive-url = https://web.archive.org/web/20121209021155/http://www.news.cornell.edu/stories/April11/endeavoursatellite.html | archive-date = 9 December 2012 | df = dmy-all }}</ref> In April 2014, the nanosatellite [[KickSat]] was launched aboard a [[Falcon 9]] rocket with the intention of releasing 104 femtosatellite-sized chipsats, or "Sprites".<ref name="sfn20140413">{{cite news |url=http://www.spaceflightnow.com/falcon9/009/140413kicksat/ |title=Crowd-funded stowaway to deploy 104 tiny satellites |work=Spaceflight Now |first=Stephen |last=Clark |date=13 April 2014 |access-date=15 May 2014 |url-status=live |archive-url=https://web.archive.org/web/20140516065713/http://www.spaceflightnow.com/falcon9/009/140413kicksat/ |archive-date=16 May 2014}}</ref><ref name="esa-kicksat">{{cite web |url=https://directory.eoportal.org/web/eoportal/satellite-missions/content/-/article/kicksat |title=KickSat Nanosatellite Mission |publisher=European Space Agency |access-date=15 May 2014 |url-status=live |archive-url=https://web.archive.org/web/20140516065644/https://directory.eoportal.org/web/eoportal/satellite-missions/content/-/article/kicksat |archive-date=16 May 2014}}</ref> In the event, they were unable to complete the deployment on time due to a failure of an onboard clock and the deployment mechanism reentered the atmosphere on 14 May 2014, without having deployed any of the {{nowrap|5-gram}} femtosats.<ref>{{Cite web | url=http://www.arrl.org/news/kicksat-re-enters-atmosphere-without-deploying-sprite-satellites |title = KickSat Re-Enters Atmosphere Without Deploying "Sprite" Satellites}}</ref>
[[ThumbSat]] is another project intending to launch femtosatellites in the late 2010s.<ref>{{cite magazine |title=Itty-Bitty Satellites Could Carry Your Experiments to Space |author=Jon Lackman |magazine=Wired |date=13 October 2015 |url=https://www.wired.com/2015/10/thumbsat/ |access-date=21 February 2016 |url-status=live |archive-url=https://web.archive.org/web/20160209130507/http://www.wired.com/2015/10/thumbsat/ |archive-date=9 February 2016}}</ref>  ThumbSat announced a launch agreement with CubeCat in 2017 to launch up to 1000 of the very small satellites.<ref>[https://www.bizjournals.com/prnewswire/press_releases/2017/07/24/SF48269 https://www.bizjournals.com/prnewswire/press_releases/2017/07/24/SF48269]</ref>{{update inline|date=January 2019}}

In March 2019, the CubeSat KickSat-2 deployed 105 femtosats called "ChipSats" into Earth orbit. Each of the ChipSats weighed 4 grams. The satellites were tested for 3 days, and they then reentered the atmosphere and burned up.<ref>{{cite web |title=Swarm of 105 tiny Sprite ChipSats successfully deployed |url=https://newatlas.com/sprite-chipsat-swarm-deployed/59994/ |website=New Atlas |date=6 June 2019}}</ref><ref name=stanford20190603>{{cite news |title=Stanford and NASA Ames researchers put inexpensive chip-size satellites into orbit |work=Stanford News |date=3 June 2019 }}</ref>

== Technical challenges ==
{{unreferenced section|date=September 2013}}
Small satellites usually require innovative propulsion, [[Spacecraft attitude control|attitude control]], communication and computation systems.

Larger satellites usually use [[monopropellant]]s or [[bipropellant]] combustion systems for propulsion and attitude control; these systems are complex and require a minimal amount of volume to surface area to dissipate heat. These systems may be used on larger small satellites, while other micro/nanosats have to use electric propulsion, compressed gas, vaporizable liquids such as [[butane]] or [[carbon dioxide]] or other innovative propulsion systems that are simple, cheap and scalable.

Small satellites can use conventional radio systems in UHF, VHF, S-band and X-band, although often miniaturized using more up-to-date technology as compared to larger satellites. Tiny satellites such as nanosats and small microsats may lack the power supply or mass for large conventional radio [[transponder]]s, and various miniaturized or innovative communications systems have been proposed, such as laser receivers, antenna arrays and satellite-to-satellite communication networks. Few of these have been demonstrated in practice.

Electronics need to be rigorously tested and modified to be "space hardened" or resistant to the outer space environment (vacuum, microgravity, thermal extremes, and radiation exposure). Miniaturized satellites allow for the opportunity to test new hardware with reduced expense in testing. Furthermore, since the overall cost risk in the mission is much lower, more up-to-date but less space-proven technology can be incorporated into micro and nanosats than can be used in much larger, more expensive missions with less appetite for risk.

== Collision safety ==

Small satellites are difficult to track with ground-based radar, so it is difficult to predict if they will collide with other satellites or human-occupied spacecraft.  The U.S. [[Federal Communications Commission]] has rejected at least one small satellite launch request on these safety grounds.<ref name="gizmodo20180309">{{cite news |url=https://gizmodo.com/california-startup-accused-of-launching-unauthorized-sa-1823657316 |title=California Startup Accused of Launching Unauthorized Satellites Into Orbit: Report |work=Gizmodo |first=George |last=Dvorsky |date=9 March 2018 |access-date=19 March 2018 |url-status=live |archive-url=https://web.archive.org/web/20180320043830/https://gizmodo.com/california-startup-accused-of-launching-unauthorized-sa-1823657316 |archive-date=20 March 2018}}</ref>

== See also ==
{{Portal|Spaceflight}}
{{Div col|colwidth=22em}}
* [[Canadian Advanced Nanospace eXperiment Program]]
* [[CanSat]]
* [[DRAGONSat]] picosatellite
* [[Micro air vehicle]]
* [[N-Prize]]
* [[Nanosatellite Launch System]]
* [[Satellite formation flying]]
* [[SPHERES]]
* [[Student Space Exploration & Technology Initiative]]
* [[University Nanosatellite Program]]
* [[AMSAT]] Amateur Satellite Corp.
* [[PocketQube]]
* [[Rocket Lab]]
{{div col end}}

== References ==
{{Reflist|30em}}

== External links ==
*[http://nanosats.eu Nanosatellite and CubeSat Database]
*[http://newspace.im NewSpace Index]
*[http://hyperionorbital.com/resources/ Pico Satellite Development Resources]

{{Use dmy dates|date=October 2018}}
{{Use American English|date=January 2014}}

[[Category:Satellites by type]]
[[Category:Small satellites| ]]