Iapetus
Ia­pe­tus
Credit: NASA/JPL/Space Science Institute

Iapetus

Ia­pe­tus is one of Sat­urn’s most mys­te­ri­ous moons: this icy moon with a di­am­e­ter of 1468 kilo­me­tres presents the ob­serv­er with two hemi­spheres that have de­vel­oped in com­plete­ly dif­fer­ent ways. The hemi­sphere fac­ing the op­po­site di­rec­tion of the moon’s or­bit around Sat­urn, the so-called “trail­ing side”, as well as the po­lar ar­eas, con­sist of white ice and re­flect the light of the Sun al­most 100 per­cent; on the sur­face of the hemi­sphere fac­ing the di­rec­tion of or­bit, the so-called “lead­ing side”, how­ev­er, car­bon com­pounds cov­er the ice – cyanide and oth­er car­bon com­pounds make the sur­face as black as tar. This false-colour im­age shows the first mo­sa­ic of high-res­o­lu­tion im­age da­ta from bright side of Ia­pe­tus; it con­sists of 60 sep­a­rate im­ages, which were record­ed in Septem­ber 2007 from a dis­tance of 73 000 kilo­me­tres. This fly­by had been planned in great de­tail by staff mem­bers of the Freie Uni­ver­sität Berlin and DLR. The tran­si­tion zone be­tween both ex­tremes is es­pe­cial­ly in­ter­est­ing. De­ci­sive ex­plana­to­ry in­for­ma­tion about the cause of Ia­pe­tus’ strange char­ac­ter­is­tics has been pro­vid­ed not on­ly by the im­age da­ta from Cassi­ni, but al­so through ob­ser­va­tions per­formed with NASA’s Hub­ble Space Tele­scope. Be­yond the or­bit of Ia­pe­tus, Sat­urn is sur­round­ed by a gi­ant torus of tiny, dark dust par­ti­cles, in­clined at 27 de­grees to the equa­tor and the main ring plane. The par­ti­cles orig­i­nate from im­pacts on the small moons of Sat­urn that or­bit fur­ther out than Ia­pe­tus, such as Phoebe, whose or­bit lies in the mid­dle of the torus. The den­si­ty of the par­ti­cles is ex­treme­ly low, yet high enough for some of the small par­ti­cles that mi­grate to­wards the in­te­ri­or of the Sat­urn sys­tem are at­tract­ed by the lead­ing side of Ia­pe­tus and, over a long pe­ri­od­of time, have been col­lect­ed and com­pact­ed in­to a thin, black lay­er.

FlybyMoonDate Altitude
(km)
Flyby speed
(km/sec)

Phase-angle
(deg)

Part of mission
0Phoebe11.06.20042,0686.424pre-arrival
ATitan26.10.20041,1746.191Saturn Orbit Insertion
(SOI)
BTitan13.12.20041,1926.1102SOI
BHuygens Probe
Release
24.12.2004n/an/an/aSOI
CIapetus01.01.200565,0002.094SOI
CTitan14.01.200560,0035.493SOI
3Titan15.02.20051,5796.099nominal
4Enceladus09.03.20054976.643nominal
5Titan31.03.20052,4045.966nominal
6Titan16.04.20051,0276.1127nominal
11Enceladus14.07.20051668.264nominal
13Titan22.08.20053,6605.944nominal
14Titan07.09.20051,0756.185nominal
15Tethys24.09.20051,4959.068nominal
15Hyperion26.09.20054795.648nominal
16Dione11.10.20054999.166nominal
17Titan28.10.20051,3535.9105nominal
18Rhea26.11.20055047.387nominal
19Titan26.12.200510,4115.667nominal
20Titan13.01.20061,0006.053nominal
21Titan15.01.20062,0435.8120nominal
22Titan29.01.20062,6315.872nominal
23Titan27.02.20061,8125.992nominal
24Titan19.03.20061,9495.8148nominal
25Titan30.04.20061,8555.8121nominal
26Titan20.05.20061,8795.8163nominal
27Titan02.07.20061,9055.8148nominal
28Titan22.07.20069496.0105nominal
28Titan07.09.20061,0006.045nominal
29Titan23.09.20069606.090nominal
30Titan09.10.20069806.081nominal
31Titan25.10.20061,0306.025nominal
35Titan12.12.20061,0005.9125nominal
36Titan28.12.20061,2965.962nominal
37Titan22.02.20071,0006.2161nominal
38Titan10.03.20079816.2150nominal
39Titan26.03.20071,0106.2144nominal
40Titan10.04.20079916.2137nominal
41Titan26.04.20079816.5130nominal
42Titan12.05.20079596.2122nominal
43Titan28.05.20072,2996.1114nominal
44Titan13.06.20079656.2107nominal
45Titan29.06.20071,9336.296nominal
46Titan19.07.20071,3326.234nominal
47Titan31.08.20073,3243.187nominal
49Iapetus10.09.20071,6222.459nominal
50Titan02.10.20079736.367nominal
52Titan19.11.20079996.351nominal
53Titan05.12.20071,2956.370nominal
54Titan20.12.20079706.361nominal
55Titan05.01.20081,0146.338nominal
59Titan22.02.20081,0006.330nominal
61Enceladus12.03.20084814.4137nominal
62Titan25.03.20089996.321nominal
67Titan12.05.20081,0016.336nominal
69Titan28.05.20081,4006.321nominal
78Titan31.07.20081,6146.249extended Equinox
80Enceladus11.08.20084917.7110extended Equinox
88Enceladus09.10.20082517.7113extended Equinox
91Enceladus31.10.200816917.7110extended Equinox
91Titan03.11.20081,1056.3171extended Equinox
93Titan19.11.20081,0236.328extended Equinox
95Titan05.12.20089616.325extended Equinox
97Titan21.12.20089716.383extended Equinox
102Titan07.02.20099676.3136extended Equinox
103Titan21.03.20099666.0142extended Equinox
106Titan27.03.20099636.384extended Equinox
108Titan04.04.20094,1475.8151extended Equinox
109Titan20.04.20093,5995.8149extended Equinox
110Titan05.05.20093,2425.8146extended Equinox
111Titan06.06.20099686.0135extended Equinox
112Titan22.06.20099556.0128extended Equinox
113Titan08.07.20099656.0120extended Equinox
114Titan24.07.20099556.0112extended Equinox
115Titan09.08.20099706.0104extended Equinox
116Titan25.08.20099706.086extended Equinox
119Titan12.10.20091,3006.099extended Equinox
120Enceladus02.11.2009997.790extended Equinox
121Enceladus21.11.20091,6027.887extended Equinox
122Titan12.12.20094,8505.7124extended Equinox
123Titan28.12.20099555.986extended Equinox
124Titan12.01.20101,0735,995extended Equinox
125Titan28.01.20107,4905.769extended Equinox
126Titan13.02.20109,5465.899extended Equinox
127Titan02.03.20101018.687extended Equinox
129Titan05.04.20107,4625.773extended Equinox
129Dione07.04.20105038.479extended Equinox
130Enceladus28.04.2010996.593extended Equinox
131Enceladus18.05.20104346.5114extended Equinox
131Titan20.05.20101,4005.9112extended Equinox
132Titan05.06.20102,0445.887extended Equinox
133Titan07.06.20101,0055.982extended Equinox
134Titan21.06.20108805.982extended Equinox
136Enceladus13.08.20102,5506.885extended Equinox
138Titan24.09.20108,1755.760extended Equinox
140Titan11.11.20107,9215.6121extended Equinox
141Enceladus30.11.2010486.378extended Equinox
142Enceladus21.12.2010486.289extended Equinox
143Rhea11.01.2011768.0101Solstice Mission
145Titan18.02.20113,6515.862Solstice Mission
147Titan19.04.201110,0535.6101Solstice Mission
148Titan08.05.20111,8735.947Solstice Mission
149Titan20.06.20111,3595.973Solstice Mission
153Titan12.09.20115,8225.8159Solstice Mission
154Enceladus01.10.2011997.4102Solstice Mission
155Enceladus19.10.20111,2307.5118Solstice Mission
156Enceladus06.11.20114967.474Solstice Mission
158Dione12.12.2011998.749Solstice Mission
158Titan13.12.20113,5865.8100Solstice Mission
159Titan02.01.201229,4155.576Solstice Mission
160Titan30.01.201231,1315.496Solstice Mission
161Titan19.02.20123.8035.8143Solstice Mission
163Enceladus27.03.2012747.5105Solstice Mission
164Enceladus14.04.2012747.5104Solstice Mission
165Enceladus02.05.2012747.5100Solstice Mission
166Titan22.05.20129555.971Solstice Mission
167Titan07.06.20129595.975Solstice Mission
169Titan24.07.20121,0125.958Solstice Mission
172Titan26.09.20129565.947Solstice Mission
174Titan13.11.20129735.968Solstice Mission
175Titan29.11.20121,0145.944Solstice Mission
181Titan17.02.20131,9785.835Solstice Mission
183Rhea09.03.20139979.3138Solstice Mission
185Titan05.04.20131,4005.869Solstice Mission
190Titan13.05.20139705.950Solstice Mission
194Titan10.07.20139645.946Solstice Mission
195Titan26.07.20131,4005.858Solstice Mission
197Titan12.09.20131,4005.821Solstice Mission
198Titan14.10.20139615.925Solstice Mission
199Titan01.12.20131,4005.850Solstice Mission
200Titan01.01.20141,4005.835Solstice Mission
201Titan02.02.20141,2365.944Solstice Mission
202Titan06.03.20141,5005.853Solstice Mission
203Titan07.04.20149635.960Solstice Mission
204Titan17.05.20142,9935.7158Solstice Mission
205Titan18.06.20143,6585.6165Solstice Mission
206Titan20.07.20145,1035.6171Solstice Mission
207Titan21.08.20149645.812Solstice Mission
208Titan24.08.20141,0135.831Solstice Mission
209Titan22.09.20141,4005.821Solstice Mission
210Titan10.12.20149805.856Solstice Mission
211Titan11.01.20159705.846Solstice Mission
212Titan12.02.20151,2005.855Solstice Mission
213Titan16.03.20152,2755.770Solstice Mission
215Titan07.05.20152,7225.734Solstice Mission
217Dione16.06.20155167.358Solstice Mission
218Titan07.07.201510,9535.678Solstice Mission
220Dione17.08.20154736.467Solstice Mission
222Titan28.09.20151,8398.563Solstice Mission
223Enceladus14.10.20151,8398.563Solstice Mission
224Enceladus28.10.2015498.5118Solstice Mission
225Titan13.11.201511,9205.592Solstice Mission
228Enceladus19.12.20154,9999.5114Solstice Mission
230Titan16.01.20163,8185.799Solstice Mission
231Titan01.02.20161,4005.8120Solstice Mission
232Titan16.02.20161,0185.9122Solstice Mission
234Titan04.04.20169905.9138Solstice Mission
235Titan06.05.20169715.9138Solstice Mission
236Titan07.06.20169755.9124Solstice Mission
238Titan25.07.20169765.9101Solstice Mission
239Titan10.08.20161,6005.892Solstice Mission
243Titan27.09.20161,7375.888Solstice Mission
248Titan14.11.20161,5825.880Solstice Mission
250Titan29.11.20163,2235.782Solstice Mission
270Titan22.04.20179795.861Solstice Mission

Contact
  • Elke Heinemann
    Ger­man Aerospace Cen­ter (DLR)
    Pub­lic Af­fairs and Com­mu­ni­ca­tions
    Telephone: +49 2203 601-2867
    Fax: +49 2203 601-3249

    Contact
  • Ulrich Köhler
    Pub­lic re­la­tions co­or­di­na­tor
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Rutherfordstraße 2
    12489 Berlin
    Contact

Cookies help us to provide our services. By using our website you agree that we can use cookies. Read more about our Privacy Policy and visit the following link: Privacy Policy

Main menu