2005-001A
NASA Discovery class mission which will attempt to hit a comet nucleus in 2005. The Jet Propulsion Lab's Deep Impact probe will be built by Ball Aerospace and consists of a flyby spacecraft and an impactor. Deep Impact will be launched from Cape Canaveral in Dec 2004 and head for comet 9P/Tempel-1. 24 hours before impact, the 350-kg copper impactor spacecraft will separate. The impactor uses autonomous navigation software, pioneered on the Deep Space 1 mission, to control firings of its gas jets and close in for a 10 km/s collision with Tempel-1's nucleus. The 20-meter-deep crater will break through the nuclear mantle and expose the material underneath. The crater and ejecta will be imaged by the flyby probe's camera and infrared spectrometer and by Earthbound astronomers, treated to a spectacular extraterrestrial fireworks display timed for July 4th, 2005. If comets become dormant because their ices are exhausted, the display will soon be over, but if dormancy is due to the mantle locking in the volatile material, Tempel-1 may continue to shine from the hotspot as it loses material from the crater area.
Discovery mission selected 1999 Jul.
Deep Impact has a launch mass of 973 kg (JScR; Delta media kit 976; Ball kit says 1020 kg, NASA kit says 601 kg full, 515 kg dry plus impactor 372 kg full 364 kg dry). and contains a 370 kg copper penetrator which would impact P/Tempel-1 at 10.2 km/s and make a 20-m deep crater to expose raw comet nucleus material. PI is M A'Hearn (U Md). Built by Ball Aerospace. Project management at JPL. Launch Jan 2004 by Delta 7925, encounter 2005 Jul 4.
Shortly before launch it was determined that the originally desired trajectory could not be attained, requiring a significant initial trajectory correction by the spacecraft. In the event the C3 energy was 1.6 sigma low (10.7554 km2/s2 vs 10.8577); achieved asymptote was (199.3849, -2.8416). a TCM-1 of 27.7 m/s was required (in the event,28.6m/s was targeted due to other considerations). The initial intended Tempel-1 B-plane miss was (-60211, 10083) km with TCA at 2005 Jul 4 0622:43 UTC.
After the impact the comet brightened by a factor of 5 within 15 minutes and faded slowly over a few hours.
The flyby spacecraft was reactivated in 2007 for a second comet flyby mission. It was renamed EPOXI (EPOCh and DIXI). The spacecraft will fly by 103P/Hartley 2.
The Deep Impact flyby spacecraft has sufficient fuel to undertake further studies. The new mission, named EPOXI, is comprised of two projects with different scientific objectives. DIXI, the Deep Impact Extended Investigation, continues the original Deep Impact theme of studying comets by flying past comet Hartley 2. A comparison of Hartley 2 with comets observed by other spacecraft missions in order to help determine which cometary features are primordial and which are the result of subsequent evolutionary processes will be a primary focus of the investigation.
EPOCh, Extrasolar Planet Observation and Characterization, will use the Deep Impact high-resolution instrument (HRI) to observe three stars with known transiting giant planets to characterize those planets and to search for others. This is accomplished by using the HRI as a photometer to measure the light coming from the star in frequent images (a typical rate of every 50 seconds) as the planet transits and is later eclipsed by the star. Characteristics of the light from the planet are measured when it is eclipsed by the star, and the presence of other planets may be detected by their transits or by gravitational effects on the position of the giant planet. Planets as small as three Earth masses may be detected in this way. EPOCh will also observe the Earth in visible and infrared wavelengths to allow comparisons with future discoveries of Earth-like planets around other stars.
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| Date | Time | Event | Orbit |
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| 2005 Jan 12 | 1847:08 | Launch by Delta 7925-9.5 | CC SLC17B |
| | | T+1:03 SRM 1-6 out |
| | | T+1:05 SRM 7-9 on |
| | | T+1:06 SRM 1-6 sep |
| | | T+2:08 SRM 7-9 out |
| | | T+2:11 SRM 7-9 sep |
| | 1851:31 | T+4:23 MECO |
| | 1851:39 | T+4:31 Stage 1 sep |
| | 1851:45 | T+4:37 SES-1 |
| | 1852:04 | T+4:56 Fairing |
| | 1856:40 | T+9:32 SECO-1 | 167 x 167 x 29.74 |
| | 1911:30 | T+24:22 SES-2 |
| | 1913:12 | T+26:04 SECO-2 | 163 x 4170 x 29.7? |
| | 1914:05 | T+26:57 St 2 sep |
| | 1914:42 | T+27:34 TES |
| | 1916:10 | T+29:02 TECO | 179 x -86410 x 29.73 |
| | 1920:52 | T+33:44 Yo yo deploy |
| | 1920:57 | T+33:49 Stage 3 sep |
| | 1924:42 | T+37:34 Target interface point |
| | | Delta SES-3 depletion | 153 x 4145 x 24.0 |
| 2005 Jan 13 | 0407 | Pass EL1:4 |
| 2005 Jan 13 | 2100? | Pass lunar orbit |
| 2005 Jan 17 | 1551 | Leave Earth sphere 1.5Mkm |
| 2005 Jan 19 | | Range 1.9Mkm |
| 2005 Feb 1 | | | 544.14d 0.9809AU x 1.6276AU x 0.64 |
| 2005 Feb 11 | 1900 | TCM-1 28 m/s |
| 2005 May 5 | 1900 | TCM-3A 95s 5.05m/s |
| 2005 Jun | | | 545.83d 0.9764AU x 1.6378AU x 0.48 |
| 2005 Jun 23 | 1900:00 | E-11d TCM-3B 6m/s |
| 2005 Jul 3 | 0000 | TCM-5 |
| 0600 | Impactor release E-24h | 0.9842 x 1.6405 AU x 0.49 |
| | 0613 | Flyby TCM, E-23h48m, 101m/s 14m |
| | 0616 | Impactor detumble |
| | 0627 | TCM completed |
| 2005 Jul 4 | |
| | | E-2h autonav on |
| | 0415 | ITM-1 E-100m 1.3m/s 21.5s 3.1 kg, |
| | 0510 | ITM-2 E-35m 0.4 kg 2.2m/s, range 21600 km |
| | 0532 | ITM-3 E-12min 2.3m/s 44s 0.4 kg, range 7700 km |
| | 0544TDB | Enter Tempel 1 sphere |
| | 0546:02TDB | Impact at 10.298 km/s |
| 0559:49 | Flyby Tempel 1 TCA 500 km |
2005 Jul 20 | | TCM-6 900s |
| 2006 Jan | | DI reactivated |
| 2007 Jan 1 | | | 0.981 x 1.638 AU x 0.66 |
| 2007 Sep 24 | | DI reactivated, renamed EPOXI, Cruise-1 |
| 2007 Nov 1 | | DI TCM-9 |
| 2007 Dec 3 | | EPOCh observations begin |
| 2007 Dec 27 | 0308 | Enter Earth Sphere 1.5Mkm |
| 2007 Dec 29 | 0000? | Enter Earth SOI |
| 2007 Dec 31 | 1930 | Earth flyby | 15566 x -95379 x 19.8 |
| 2008 Jan 3 | 1400? | Leave Earth SOI |
| 2008 Jan 5 | 1154 | Depart Earth sphere 1.5Km |
| 2008 Jan 26 | | Cruise-2 |
| 2008 Feb 1 | | | 0.91 x 1.09 AU x 4.2 |
| 2008 Dec 1 | | | 364.88 0.909 x 1.090 AU x 4.2 |
| 2008 Dec 25 | 0445 | Enter Earth sphere 1.5Mkm |
| 2008 Dec 29 | 2142 | Earth flyby 43450 km R=49828km | 43449 x -122772 x 92.81 |
| 2009 Jan 1 | 1800? | Leave Earth sphere |
| 2009 Jan 1 | | | 368.07d 0.982 x 1.027AU x 6.6 |
| 2009 Jan 3 | 1456 | Leave Earth sphere 1.5Mkm |
| 2009 Jun 1 | | | 367.45d 0.982 x 1.026AU x 6.6 |
| 2009 Jun 27 | 0021 | Enter Earth sphere 1.5Mkm |
| 2009 Jun 29 | 0741 | Distant Earth pass at 1.34Mkm |
| 2009 Jul 1 | 1457 | Depart Earth sphere |
| 2009 Aug 1 | | | 365.26d 0.975 x 1.025AU x 6.5 |
| 2009 Dec 26 | 0335 | Enter Earth sphere 1.5Mkm |
| 2009 Dec 28 | 1018 | Distant Earth pass at 1.32 Mkm |
| 2009 Dec 30 | 1657 | Depart Earth sphere 1.5Mkm |
| 2010 Feb 25 | | | 363.07d 0.983 x 1.029AU x 6.6 |
| 2010 Jun 23 | 0144 | Enter Earth sphere 1.5Mkm |
| 2010 Jun 24 | 2345 | Enter Earth sphere |
| 2010 Jun 27 | 2203 | Earth flyby 30480 km | 30480 x -114582 x 103.1 |
| 2010 Jun 30 | 0000 | 675000 km range |
| 2010 Jun 30 | 2000? | Leave Earth sphere |
| 2010 Jul 2 | 1806 | Leave Earth sphere 1.5Mkm |
| 2010 Aug 1 | | | 420.18 0.975 x 1.221 AU x 3.2 |
| 2010 Sep 5 | | Comet Approach Phase, begin imaging |
| 2010 Sep 29 | 1800 | TCM-20 60s 1.5m/s |
| 2010 Oct 27 | 1800 | TCM-21 60s 1.6m/s |
| 2010 Oct 28 | | Comet perihelion 1.06AU |
| 2010 Nov 2 | 1500 | TCM-22 7s 1.4m/s |
| 2010 Nov 4 | | | 0.975 x 1.219 x 3.2 |
| | 1359:31UTC | 750 km 103P/Hartley-2 flyby | 0.969 x 1.220 AU x 3.2 OWLT=8.8min |
| 2010 Nov 30 | | End comet encounter phase |
| 2011 Nov 24 | | Targeting burn 140s 9m/s |
| 2011 Dec 17 | | | 0.969 x 1.209 AU x 3.2 |
| 2012 Oct 4 | | Targeting burn for 2002 GT |
| 2013 Aug 11 | | Loss of contact with DIF |
| 2020 Jan 4 | 0508 | Flyby of (163249) 2002 GT at 320 km? |
The science goals are to study the mantle depth, interior composition and structural properties of a comet nucleus, and to study the surface of the nucleus to find out how comets become dormant.
24 hours before impact, the impactor separates from the flyby spacecraft. Impact is at 10.2 km/s. The KE of impact is 18 GJ or 4.5 tons of TNT.
Impactor is 370 kg and is made largely of copper (since Al would contaminate the spectrum of the debris flash). Size is 1.0m long and 1m dia.
FLyby + impactor is total of 3.3 long 1.7 wide 2.3 high. pentagonal cylinder + panel + science platform.
Flyby:
Payload:
- Debris shield
- AOCS Hydrazine with 190m/s dV, 5 kNs total
- HRI High Resolution Instrument
- Visible CCD camera 0.30m, f/35, FOV 0.1 deg
- IR spectrometer 512 x 256 HgCdTe array, 1-5 microns
- Special imaging module
- MRI Medium Resolution Instrument
- Multispectral CCD camera 0.12m aperture, f/17.5, FOV 0.6 deg
