Deep Impact (Discovery 7) --> EPOXI

Launch data: Designation  28517 / 05001A Launch date  12 Jan 2005 - 18:47:08 UT Launch site  CC, SLC-17B Launch vehicle  Delta 7925-9.5 (#D311) Mission  Comet impact and flyby Heliocentric orbit Perihelion / Aphelion  0.981 x 1.628 Incl. to ecliptic  0.6 ° Period   min

Deep Impact (with Impactor) [Ball]

Spacecraft data: Prime contractor  Ball Aerospace, JPL Operator  NASA Platform   Mass at launch: Fly-by spacecraft  601 kg (86 kg of propellant) Impactor  372 kg (8 kg of propellant) dim: 1 dia, 1 long Launch Mass  973 kg Basic shape  Box + panel Dimension  3.3 x 1.7 x 2.3 2.8 span Solar array   Stabilization   DC power   Design lifetime

Description:

The objectives of the Deep Impact mission are to rendezvous with comet P/Tempel-1 and launch a projectile into the comet nucleus. Observations will then be made of the ejecta, much of which will represent pristine material from the interior of the comet, the crater formation process, the resulting crater, and any outgassing from the nucleus, particularly the newly exposed surface. This project was selected as a Discovery class mission in July, 1999.

Deep Impact is a two-part spacecraft, comprising a Fly-by spacecraft and an Impactor. The Impacter is a 372 kg cylindrical copper attached to a flyby bus, the launch mass of the flyby bus and impactor is 973 kg. The Fly-by spacecraft is a box-shaped honeycombed aluminum framework with a flat rectangular Whipple debris shield mounted on one side to protect components during comet close approach. Mounted on the framework are one high- and one medium-resolution instrument, each of which consists of an imaging camera and an infrared spectrometer which will be used to observe this ejected ice and dust, much of which will be exposed to space for the first time in over 4 billion years. The medium resolution camera has a field of view (FOV) of 0.587 degrees and a resolution of 7 m/pixel at 700 km distance and is used for navigation and context images. The high resolution camera has a FOV of 0.118 degrees and a resolution of 1.4 m/pixel at 700 km. The infrared spectrometers cover the range from 1.05 to 4.8 micrometers with FOV of 0.29 degrees (hi-res) and 1.45 degrees (lo-res). The total flyby bus instrument payload has a mass of 90 kg.

The flyby spacecraft measures approximately 3.2 m x 1.7 m x 2.3 m, is three-axis stabilized and uses a hydrazine propulsion system. Communications with the ground from the flyby bus are via X-band (8.000 MHz) through a 1 meter diameter parabolic dish antenna mounted on a 2-axis gimbal and via S-band between the impactor and flyby spacecraft. The maximum data rate will be 400 kbps. Power of 620 W at the encounter is provided by a 7.5 square meter solar array and stored in a small NiH2 battery. The projectile is made of copper so it will be easily identifiable in the spectra after the projectile is largely vaporized and mixed in with the comet ejecta on impact. The impactor is equipped with an Impactor Targeting Sensor, an imager which provides knowledge for autonomous control and targeting, and a cold-gas attitude control system.

Mission:

• The Boeing Delta 7925 rocket reached a 167 x 167 km x 29.7 deg parking orbit at 18:56 UT, and then restarted at 19:11 UT to enter a 163 x 4170 km orbit. The third stage separated and burned at 19:14 UT, and after separation at 19:21 UT there were four objects on an Earth escape trajectory: the PAM-D third stage, two despin weights, and the Deep Impact probe.
• By Jan 19, 2005 the probe was 1.9 million km from Earth and on track to enter a 0.981 x 1.628 AU solar orbit inclined 0.6 deg to the ecliptic.
• The 372 kg Impactor spacecraft separated from the DI Flyby vehicle at 06:00 UT on Jul 3, 2005. Impactor hit comet 9P/Tempel 1 at 10.2 km/s at 0544:58 UT on Jul 4, 2005 as the DI Flyby spacecraft sent back spectacular pictures of the resulting plume. Flyby passed about 500 km from the comet at 05:59 UT, at which time it was in 'shields up' mode pointing away from the comet to protect itself from the plume.
• The comet and spacecraft will be about 0.89 AU from Earth and 1.5 AU from the Sun during the encounter. Real time return of selected impactor images and flyby images and spectra will be returned to Earth during the encounter. Primary data return will be over the first day after encounter, with a 28 day supplemental data return period. Earth-based observatories will also study the impact. The spacecraft will range over a distance of 0.93 to 1.56 AU from the Sun during the mission. End of mission is scheduled for August 2005.
• Name changed into EPOXI in 2007 for an extended mission.
  
• The Deep Impact (EPOXI) spacecraft flew 700 km from comet 103P/Hartley at around 14:01 UTC on Nov 4, 2010. It revealed an active cometary nucleus with rough and smooth areas, and jets coming from the rough areas.
• The Deep Impact/EPOXI mission has come to an end. Last contact with the Deep Impact Flyby spacecraft was on Aug 11, 2013 and attempts to revive it have been abandoned.
  In Oct 2012 the probe was targeted towards minor planet (163249) 2002 GT, which it might have reached in 2020. DIF is in a 0.97 x 1.21 AU x 3.2 deg heliocentric orbit.