2007-043A
Dawn will take 9 years to orbit Vesta and Ceres. Uses DS1 type ion engine: 3 NSTAR Xe thrusters. Star-2 bus with LEOStar-2 avionics and NASA/JPL NSTAR propulsion.
Size is 1.64 x 1.27 x 1.77m with 19.7m span.
Mass 1217.7 kg full, 746.9 kg dry with 425.2 kg of Xe and 45.6 kg of hydrazine (Marc Rayman, personal comm.)
288 kg of Xe are used to get to Vesta; 89 kg more are needed to get to Ceres. Orbit insertion is done with a hydrazine engine.
Launch by Delta 7925H to C3 = 10.91 km2/s2.
RHill is 40220 km.
For Sep 26 launch, C3 = 11.40 km2/s2
800 to 100 km orbits.
JPL mission, PI at UCLA, OSC/Dulles contractor, derived from Indostar.
The mission will give multicolor imagery of Vesta and Ceres, and optical and infrared surface spectra; topographic profiles at 30-meter resolution, and measurements of the gravity and magnetic fields. Chemical composition will be found via the gamma ray spectrometer.
| Dawn | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 2007 Sep 27 | 1134:00 | Launch by Delta 7925H | CC SLC17B |
| T+1:17 SRM 1-6 off | |||
| T+1:19 SRM 7-9 on | |||
| T+1:20 SRM 1-3 sep | |||
| T+1:21 SRM 5-6 sep | |||
| T+2:35 SRM 7-9 out | |||
| T+2:39 SRM 7-9 sep | |||
| T+4:22 MECO | |||
| T+4:31 Stage 1 sep | |||
| T+4:36 SEIG-1 | |||
| T+4:41 Fairing sep | |||
| 1142:58 | T+8:58 SECO-1 | 185 x 186 x 28.7 | |
| 1225 | T+51:35 SEIG-2 | |
| 1228 | T+54:14 SECO-2 | ||
| 176.5 x 6819.0 x 28.64 | |||
| 1229 | T+55:07 Stage 2 sep | ||
| 1229 | T+55:44 TES 212 km | ||
| 1231 | T+57:07 TECO | ||
| 1235? | Yoyo despin | ||
| 1236 | T+1:02:01 Stage 3 sep | 214 x -86167 x 28.71 | |
| 209 x -83420 x 28.9 | ||
| 1239 | TIP T+1:05:44 | ||
| 1240:50 | C3 = 11.319 at RLA,DLA= (98.89,28.48) | ||
| T+1:16:40 Stage 2 SEIG-3 | |||
| T+1:17:04 SECO-3 | |||
| 2115 | Pass EL1:4 | ||
| 2007 Oct 2 | 0700 | Leave Earth sphere 1.5Mkm | |
| 522.5d 1.016 x 1.523 AU x 2.16 | |||
| 2007 Sep 27 | v(sun-rel) 38.95 km/s | ||
| 2007 Dec 17 | Interplanetary cruise phase | ||
| 2007 Dec 17 | Ion drive on, ion thruster 3 | ||
| 2008 May 12 | Ion drive off | ||
| 2008 May 14 | Ion drive on | ||
| 2008 May 27 | 38 kg used | ||
| 2008 Jun 17 | Ion thruster 3 off, thruster 1 on | ||
| 2008 Aug 8 | 1.68AU from Sun, at 20.77 km/s, 55 kg used, dv so far = 1.38 km/s | ||
| 2008 Sep 27 | dv so far = 1.68 km/s | 1.21 x 1.68 AU x 1.4 | |
| 2008 Oct 31 | Ion drive off, 82 percent activity, dv = 1.81 km/s, 72 kg | ||
| 2008 Nov 10 | 1107 | At max Earth distance of 2.56AU | |
| 2008 Nov 21 | 0031 | TCM-1 0.6m/s | |
| 0242 | TCM completed | ||
| 2008 Dec 1 | 639.37d 1.2200AU x 1.6849AU x 1.92 | ||
| 2009 Feb 13 | 0512 | Enter M sphere 1.08Mkm | |
| 2009 Feb 18 | 0027:58 | Mars gravity assist 543 km alt, 5.31 km/s | 543 x -20665 x 119.5 deg |
| 2009 Feb 22 | 1951 | Depart M sphere | |
| 2009 Mar 1 | 730.71d 1.3691AU x 1.8063AU x 6.50 | ||
| 2009 Apr 17 | 0007 | Perihelion at 1.37 AU | |
| 2009 Jun 8 | Ion drive on | ||
| 2009 Sep 27 | Xe prop used 103 kg (of 425 kg) | 1.42 x 1.87 AU x 6.2 deg | |
| 2009 Nov 13 | Enters main belt at 1.666 AU | ||
| 2009 Nov 30 | Ion drive off | ||
| 2009 Dec 4 | Ion drive on | ||
| 2010 Jan 4 | Thruster 1 off, thruster 2 on | ||
| 2010 Apr 28 | LT=13.5min | ||
| 2010 Jun 5 | Total dV reaches 4.29 km/s, beat DS1 record | ||
| 2010 Jul 5 | Dawn 1.97AU from Sun | 964.25d 1.752 x 2.068AU x 6.8 deg | |
| 2011 May 3 | Begin approach phase | ||
| 2011 May 10 | 1 M km | ||
| 2011 May 11 | 2.11 x 2.43 AU x 7.04 | ||
| 2011 May 24 | Range 640000 km | ||
| 2011 Jun 23 | Range 158000 km | ||
| 2011 Jun 24 | 1243 | 150900 km | |
| 2011 Jun 26 | 0024 | 137100 km | |
| 2011 Jun 27 | 0721 | 126000 km, in Vesta Hill sphere | |
| 1521 | 123300 km, rdot 0.1 km/s | ||
| 1921 | 121900 km | ||
| 2011 Jun 28 | 2031 | 113400 km | |
| 2011 Jul 2 | 1300 | 80900 km | |
| 2011 Jul 10 | 1448 | 34800 km | |
| 1921 | 34000 km | ||
| 2011 Jul 16 | 0130 | 16600 km | |
| 0348 | Orbit capture at 16000 km | ||
| 2011 Jul 16 | Vesta high orbit: dV 50 m/s relative to Vesta at 15900 km | ||
| rev 1 , 10 day thrusting orbit | |||
| rev 2, 4 day thrusting | |||
| 2011 Jul 23 | 5200 km circular orbit, stop thrust | ||
| 2011 Jul 29 | Begin descent to survey orbit | ||
| 2011 Aug 2 | 0707 | Vesta survey orbit insertion, 3 day, Vc=76 m/s | 69hr 2700 x 2700 |
| 2011 Aug 11 | Imaging survey begins | ||
| 2011 Aug 31 | Begin descent to HAMO; 30 deg node change | ||
| 2011 Sep 18 | Enter HAMO, Vc=135 m/s | ||
| HAMO Mapping orbit | 12.3hr 680 x 680 x 90 | ||
| 2011 Sep 26 | Orbit adjust | ||
| 2011 Sep 27 | Orbit adjust | ||
| 2011 Sep 29 | Begin HAMO mapping | ||
| 2011 Nov 2 | Begin thrusting for descent to LAMO | ||
| Vesta LAMO close orbit | |||
| 2011 Dec 12 | LAMO arrival, 210 km | ||
| 2012 May 1 | Raise orbit to HAMO2 | ||
| 2012 May 8 | Alt 275 km, thrusting | ||
| 2012 May 15 | Alt 355 km, thrusting | ||
| 2012 May 22 | Alt 450 km, thrusting | ||
| 2012 May 29 | Alt 590 km, thrusting | ||
| 2012 Jun 5 | Alt 680 km | ||
| 2012 Jun 5 | HAMO2 at 680 km x 94 deg | ||
| 2012 Jun 15 | Begin HAMO2 mapping | ||
| 2012 Jul 25 | 1645 | Vesta departure, begin raising orbit | |
| 2012 Aug 8 | Raising orbit, 1900 km | ||
| 2012 Aug 10 | reaction wheel failed, 2100 km | ||
| 2012 Aug 17 | Resume burn | ||
| 2012 Aug 20 | 3000 km | ||
| 2012 Sep 5 | 0626 | Enter solar orbit | |
| 2013 Nov 11 | Begin coast phase | ||
| 2013 Dec 9 | Resume thrust | ||
| 2014 Sep 11 | Safe mode due to solar flare, | ||
| 2014 Sep 16 | Resume thrust | ||
| 2014 Dec 29 | Range 626000 km | 2.49 x 2.99 AU x 10.1 deg | |
| 2015 Jan 26 | 1900? | Within Sun-Ceres-L1, 228000 km | |
| 2015 Feb 23 | 1900? | Pass at 39073 km | 38616 x -81369 x 34.1 |
| 2015 Mar 6 | 1239 | Ceres orbit | 61000 x ? x 34.0 |
| 2015 Mar 15 | Ceres orbit insertion | ||
| 24832 x 81319 x 33.6 | |||
| 2015 Mar 19 | 75846 km apoceres | ||
| 2015 Mar 20 | 11634 x 76628 x 30.1 | ||
| 2015 Mar 25 | 1200 | 4721 x 85818 x 22.5 | |
| 2015 Mar 28 | 2200 | 2781 x 95913 x 40.0 | |
| 2015 Apr 3 | 0600 | 8441 x 102148 x 80.8 | |
| 2015 Apr 7 | 1900 | 15063 x 73015 x 89.1 | |
| 2015 Apr 14 | 1200 | 15895 x 62483 x 89.9 | |
| 2015 Apr 18 | 1940 | 16428 km periceres | |
| 2015 Apr 23 | RC3 orbit, 8400 km | ||
| 2015 May 9 | Begin descent to Survey | ||
| 2015 Jun 3 | Enter lower orbit | 4400 km orbit Survey | |
| 2015 Jul 1 | 0532 | Ion engine on to lower orbit | |
| 0549 | Safemode, ion engine abort | ||
| 2015 Jul 2 | out of safe mode, in 4400 km | ||
| 2015 Jul 14 | Resume thrust | ||
| 2015 Jul 16 | End test thrust | ||
| 2015 Aug 13 | In third science orbit at 1470 km, HAMO | ||
| 2015 Aug 18 | 0453 | Begin mapping phase | |
| 2015 Oct 23 | Ion on, begin descent to LAMO | ||
| 2015 Dec 15 | s | Ceres close orbit | 380 x 380 |
| 2016 Dec | XMO3 (Extended mission orbit 3) | 7520 x 9350 | |
| 2017 Feb 22 | Ion ascent | 7523 x 9326 x 84.9 | |
| 2017 Feb 26 | End of ascent phase 1 | 9202 x 16364 x 85.1 | |
| 2017 Mar 8 | Ion ascent | ||
| 2017 Mar 12 | End of ascent phase 2 | 10462 x 53243 x 85.5 | |
| 2017 Apr 22 | Ion orbit adjust | ||
| 2017 Apr 23 | Reaction wheel 3 failure | ||
| 2017 Jun 22 | 13355 x 52796 x 60.5 | ||
| 2017 Jun 22 | Ion engine adjust, peri to 5400 km | ||
| 2018 Apr | IE on | ||
| 2018 May 14 | IE off, XMO6 | 450 x 4700 | |
| 2018 May 31 | IE on, Lowering orbit | ||
| 2018 Jun 6 | Ion engine off XMO7 | 35 x 4000 km | |
Payload:
- Ion propulsion system; 3 NSTAR Xe thrusters
- Hydrazine engine 12 x 0.9N engines (from Indostar) MR-103G
- 1.4m HGA
- GaAs solar arrays
- FC Framing cameras
- VIR Visible/IR Mapping spectrometer (DLR/IAS-Roma) 0.35-5.0 microns.
- GRaND Gamma Ray and Neutron spectrometer (LANL)
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