Просмотр кода страницы Английская Википедия:ASTERIA (spacecraft)

{{Английская Википедия/Панель перехода}}
{{short description|CubeSat testing technologies for the detection of exoplanets}}
{{Infobox spaceflight
| name                  = ASTERIA (Arcsecond Space Telescope Enabling Research in Astrophysics)
| names_list            = ExoplanetSat (2011)

<!--image of the spacecraft/mission-->
| image                 = ASTERIA CubeSat space telescope.jpg
| image_caption         = ASTERIA during testing. It is a 6U CubeSat space telescope for the detection of [[exoplanets]]

<!--Basic details-->
| mission_type          = Technology demonstrator 
| operator              = [[NASA]]
| COSPAR_ID             = 1998-067NH
| SATCAT                = 43020
| website               = {{url|https://www.jpl.nasa.gov/cubesat/missions/asteria.php}}<!--Homepage of the craft/mission, OFFICIAL PAGES ONLY-->
| mission_duration      = Nominal: 90 days<br> Extension: up to 1 year <br> Achieved: {{time interval|20 November 2017|5 December 2019|show=ymd|sep=,}}
| orbits_completed      = <!--number of times the spacecraft orbited the Earth - see below for spacecraft beyond Earth orbit-->

<!--Spacecraft properties-->
| spacecraft            = ASTERIA
| spacecraft_bus        = 6U [[CubeSat]] 
| manufacturer          = [[JPL]] and [[MIT]]
| launch_mass           = {{convert|12|kg|lb|abbr=on}}
| dimensions            = {{convert|10|×|20|×|30|cm|ft|abbr=on}}
| power                 = <!--in watts-->

<!--Launch details-->
| launch_date           = {{start date|2017|08|14}}, 16:31 UTC<br/>deployed: 20 November 2017
| launch_rocket         = [[Falcon-9]] 
| launch_site           = [[Kennedy Space Center|Kennedy]] [[Kennedy Space Center Launch Complex 39|LC-39A]] 
| launch_contractor     = [[SpaceX]]

<!--end of mission-->
| disposal_type         = <!--Whether the spacecraft was deorbited, decommissioned, placed in a graveyard orbit, etc-->
| declared              = <!--when the operator/agency officially ended the mission-->
| deactivated           = <!--when craft was decommissioned-->
| destroyed             = <!--when craft was destroyed (if other than by re-entry)-->
| last_contact          = 5 December 2019
| recovery_by           = <!--recovered by-->
| decay_date            = 24 April 2020<!--when craft re-entered the atmosphere, not needed if it landed-->

<!--orbit parameters-->
| orbit_reference       = [[Geocentric orbit|Geocentric]]
| orbit_regime          = [[Low Earth orbit|Low Earth]]
| orbit_apoapsis        = {{convert|406.7|km|mi|abbr=off}}
| orbit_periapsis       = {{convert|402.7|km|mi|abbr=off}}
| orbit_period          = 92.5 minutes
| orbit_inclination     = 51.6°
| apsis                 = gee

<!--Telescope parameters-->
| instrument_type       = <!--converts telescope fields to suit a camera or other similar instrument-->
| telescope_name        = <!--name, if different to the satellite-->
| telescope_type        = <!--type of telescope, mirror arrangement, etc--> 
| telescope_diameter    = <!--diameter of telescope-->
| telescope_focal_length= 
| telescope_area        = <!--wrong units or not the area: 83 mm -->
| telescope_wavelength  = [[visible spectrum]]: 390–700 nm 
| telescope_resolution  = 
| instruments           = <!--a list of instruments on the satellite-->

<!--transponder parameters-->
| trans_band            = <!--Transponder frequency bands-->
| trans_frequency       = <!--specific frequencies-->
| trans_bandwidth       = <!--bandwidth-->
| trans_capacity        = <!--capacity of the transponders-->
| trans_coverage        = <!--area covered-->
| trans_TWTA            = <!--TWTA output power-->
| trans_EIRP            = <!--equivalent isotropic power-->
| trans_HPBW            = <!--half-power beam width-->

<!--mission insignia or patch-->
| insignia              = <!--omit the "file" prefix-->
| insignia_caption      = <!--image caption-->
}}

'''ASTERIA''' ('''Arcsecond Space Telescope Enabling Research in Astrophysics''') was a miniaturized [[space telescope]] technology demonstration and opportunistic science mission to conduct [[astrophysical]] measurements using a [[CubeSat]]. It was designed in collaboration between the [[Massachusetts Institute of Technology]] (MIT) and NASA's [[Jet Propulsion Laboratory]]. ASTERIA was the first [[JPL]]-built CubeSat to have been successfully operated in space. Originally envisioned as a project for training early career scientists and engineers, ASTERIA's technical goal was to achieve [[arcsecond]]-level line-of-sight pointing error and highly stable focal plane temperature control. These technologies are important for precision [[Photometry (astronomy)|photometry]], i.e., the measurement of stellar brightness over time. Precision photometry, in turn, provides a way to study stellar activity, transiting [[exoplanets]], and other astrophysical phenomena.

ASTERIA was launched on 14 August 2017 and deployed into low Earth orbit from the [[International Space Station]] on 20 November 2017.<ref name='JPL Asteria'>[https://www.jpl.nasa.gov/cubesat/missions/asteria.php Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA)]. Jon Nelson, Jet Propulsion Laboratory, NASA.</ref> The primary mission lasted 90 days, but the satellite continued operations for 745 days through three extended missions until last successful communications were made on December 5, 2019.<ref name='Asteria EOL'>{{cite web|url=https://www.jpl.nasa.gov/news/news.php?feature=7568|title=Tiny Satellite for Studying Distant Planets Goes Quiet|publisher=JPL}}</ref> The satellite decayed 24 April 2020. The Principal Investigator was Canadian-American astronomer and planetary scientist [[Sara Seager]], from the Massachusetts Institute of Technology.<ref>Seager, Sara (Jan/Feb. 2021). "[https://wp.technologyreview.com/wp-content/uploads/2020/12/MIT-NEWS-2021-01-1.pdf My satellite would fit in a small suitcase. But it could help us find other worlds]" (excerpt from book ''The Smallest Lights in the Universe'' (2020).) ''MIT News'', pp. 12-17. Retrieved 20 May 2023.</ref>

==Overview==

The Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) was a six-unit (6U) [[CubeSat]] space telescope deployed from the International Space Station (ISS) with the goal of testing new technologies for the detection of [[exoplanet]]s using the [[Methods of detecting exoplanets#Transit photometry|transit method]].<ref name='JPL Asteria'/><ref name='ISS Asteria'>[https://www.nasa.gov/mission_pages/station/research/experiments/2513.html ISS - ASTERIA]. Victor M. Escobedo Jr. ''NASA News'', October 2017.</ref><ref name='Gunter Asteria'>[http://space.skyrocket.de/doc_sdat/asteria.htm ASTERIA]. Gunter Krebs, ''Gunter's Space Page''. 14 August 2017.</ref> The program was funded at JPL through the Phaeton Program for training early career employees.<ref name='JPL Asteria'/> Its target mission lasted for 90 days,<ref name='JPL Asteria'/> after which it was extended until the loss of contact with the spacecraft.<ref name='spaceflight101'/><ref name='Asteria EOL'/>

ASTERIA's capabilities enabled precision [[Photometry (astronomy)|photometry]] to be performed on an opportunistic basis to study stellar activity, transiting exoplanets, and other astrophysical phenomena. The technological objectives of the mission were "to achieve arcsecond-level line of sight pointing error, and highly stable focal plane temperature control for precision photometry" as a way to detect transiting [[exoplanet]]s, and characterize their host stars.<ref name='ISS Asteria'/> The pointing stability was demonstrated over 20-minute observations. Pointing repeatability would be determined over a minimum of five observations over eight or more days, with the target star being returned to the same position on the focal plane by adjusting the spacecraft orientation and focal plane position.<ref name='ISS Asteria'/>

This mission may serve as a pathfinder for a fleet of low-cost space telescopes observing multiple targets at once to refine long-term mission goals by identifying new objects for other telescopes to observe. The miniaturization of a photometric detection system into a CubeSat could enable a constellation of multiple orbiting observatories for a continuous study of the brightest [[Solar analog|Sun-like stars]] which is not possible by conventional space observatories given their cost.<ref name=Seager/> Having one or more CubeSats pointed at a target star for extended duration could reveal long-transiting exoplanets.<ref name=Seager/> This mission also provided additional information in the design of future space telescopes.<ref name='ISS Asteria'/>

==Launch==

ASTERIA was launched on board a SpaceX [[Falcon-9]] rocket (mission [[SpaceX CRS-12]]<ref name='Gunter Asteria'/>) on 14 August 2017 and it was deployed to [[low Earth orbit]] from the [[International Space Station]] in November 2017.<ref name='JPL Asteria'/> A crew member in the ISS transferred the satellite from the cargo vehicle to the [[Japanese Experiment Module]] (JEM) airlock for transfer outside the ISS.

==Design==
[[File:ASTERIA_CubeSAt_lens_alignment.jpg|thumb|lens]]

The ASTERIA concept was a follow-on to the proposed 3U [[CubeSat]] mission called ExoplanetSat that was designed in the early 2010s.<ref name='ISS Asteria'/><ref>[http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2011/5_Smith_ExoplanetSat.pdf ExoplanetSat: A Nanosatellite Space Telescope for Detecting Transiting Exoplanets] {{Webarchive|url=https://web.archive.org/web/20140812201622/http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2011/5_Smith_ExoplanetSat.pdf |date=2014-08-12 }} (PDF). Matthew W. Smith, Sara Seager, Christopher M. Pong, SungyungLim, Matthew W. Knutson, Timothy C. Henderson, Joel N. Villaseñor, Nicholas K. Borer, David W. Miller, Shawn Murphy. Massachusetts Institute of Technology. ''CubeSat Developers' Workshop''. April 20–22, 2011. San Luis Obispo, CA</ref> The ASTERIA telescope is a 6U [[CubeSat]] measuring 10 × 20 × 30&nbsp;cm, and has a mass of {{convert|12|kg|abbr=on}}.<ref name='JPL Asteria'/><ref name=Seager>[http://seagerexoplanets.mit.edu/exoplanet.htm Sara Seager- Exoplanet Space Missions] {{Webarchive|url=https://web.archive.org/web/20181207103602/http://seagerexoplanets.mit.edu/exoplanet.htm |date=2018-12-07 }}. 2017.</ref> Power was supplied by deployable fixed [[Solar panels on spacecraft|solar panels]] and rechargeable batteries.<ref name='Gunter Asteria'/>

Commercial [[reaction wheel]]s provided coarse orientation ([[Spacecraft attitude control|attitude control]]), while fine pointing control was achieved by tracking a set of guide stars on the [[active pixel sensor]] (CMOS) and moving the [[Piezoelectric sensor|piezoelectric positioning stage]] to compensate for residual pointing errors.<ref name='JPL Asteria'/> The goal was to maintain the target star image to within a fraction of a detector pixel over long durations,<ref name='ISS Asteria'/> with a pointing accuracy better than 60 [[Minute and second of arc|arcsecond]], and optimally as precise as 5 arcsecond<ref>[http://www.jossonline.com/wp-content/uploads/2017/05/Shields-Final-Characterization-of-CubeSat-Reaction-Wheel-Assemblies.pdf Characterization of CubeSat Reaction Wheel Assemblies] (PDF). Joel Shields, Christopher Pong, Kevin Lo, Laura Jones, Swati Mohan, Chava Marom, Ian McKinley, William Wilson and Luis Andrade. ''Journal of Small Satellites'', Vol. 6, No. 1, pp. 565–580. 2017.</ref> over a period of 20 minutes. The gain of each pixel was temperature sensitive, so the second objective of ASTERIA was to demonstrate milli[[Kelvin]]-level temperature stability of the imaging detector.<ref name='ISS Asteria'/>

ASTERIA demonstrated the ability to collect photometric data, and process photometric light curves from a CubeSat. Secondary applications included measuring stellar rotation periods, characterizing stellar activity of exoplanet hosts, and supporting ground-based [[Doppler spectroscopy|radial velocity measurements]] with simultaneous photometry. After the success of its 90-day planned mission, ASTERIA's extended mission targeted bright stars ([[luminosity]] Vmag < 8) with known low-mass planets discovered by the radial velocity method, that are not yet known to transit.<ref name='ISS Asteria'/>

===Scientific payload===

The telescope payload consisted of a lens and baffle assembly, a CMOS imager, and a two-axis piezoelectric positioning stage on which the [[Cardinal point (optics)#Focal planes|focal plane]] was mounted.<ref name='ISS Asteria'/> The optics section was composed of an [[f-number|f/1.4]] 85&nbsp;mm [[Carl Zeiss AG|Zeiss]] lens with a 28.6-degree field of view and six elements, focusing an image 43&nbsp;mm in diameter onto the focal plane. The focal plane array housed two active detector areas – one larger CMOS detector that fulfilled the science function, and a smaller CMOS sensor to acted as a rapid-cadence star camera to provide orientation data to the [[Spacecraft attitude control|attitude control]] system.<ref name='spaceflight101'>[http://spaceflight101.com/dragon-spx12/asteria/ ASTERIA Satellite]. ''Spaceflight 101'' 18 November 2017.</ref>

In April 2018 NASA's JPL reported that ASTERIA "has accomplished all of its primary mission objectives, demonstrating that the miniaturized technologies on board can operate in space as expected."<ref>[https://www.jpl.nasa.gov/news/news.php?feature=7097 Astrophysics CubeSat Demonstrates Big Potential in a Small Package]. Jet Propulsion Laboratory, NASA. 12 April 2018.</ref>

==References==
{{reflist}}

{{Portal|Spaceflight}}
{{Space observatories}}
{{Exoplanet search projects}}
{{Exoplanet}}
{{Orbital launches in 2017}}
{{2017 in space}}

[[Category:CubeSats]]
[[Category:Space telescopes orbiting Earth]]
[[Category:Exoplanet search projects]]
[[Category:Jet Propulsion Laboratory]]
[[Category:Massachusetts Institute of Technology]]
[[Category:Satellites deployed from the International Space Station]]
[[Category:Spacecraft decommissioned in 2019]]
[[Category:Space probes launched in 2017]]
[[Category:Secondary payloads]]
[[Category:NASA satellites orbiting Earth]]
{{Навигационная таблица/Портал/Английская Википедия}}
[[Категория:Английская Википедия]]
[[Категория:Википедия]]
[[Категория:Статья из Википедии]]
[[Категория:Статья из Английской Википедии]]