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Frequently Asked Questions

FAQs About the Mission

• Why the weird name?
• Is there enough fuel in the Deep Impact spacecraft to make a flyby of another object after the P/103Hartley flyby?
• Does the Deep Impact spacecraft have some "autonomous decision making software" like the Mars Rovers Opportunity and Spirit?
• Will you be streaming images at closest approach phase?
• Also, as the craft (correct me if I am wrong) has no plan to return to Earth, and this is the end of the mission, would it not be possible to turn IT into an impactor for 103P?
• What are the future plans for the Deep Impact Flyby Spacecraft after the EPOXI mission ends?

Answers

Q: Why the weird name?
A: Well, EPOXI is an acronym of two acronyms and it is basically a 2-part mission! When NASA looked at proposals on how to use the Deep Impact Flyby (DIF) spacecraft after the Deep Impact Mission ended, they got lots of proposals and finally accepted two of them. The first part of the mission looked at transiting exoplanets and the original mission name for that part was EPOCh -- Extrasolar Planet Observation and Charaterization. The second part was for another comet flyby and was simply called DIXI for Deep Impact Extended Investigation.
EPOCh + DIXI = EPOXI

Q: Is there enough fuel in the Deep Impact spacecraft to make a flyby of another object after the 103P/Hartley 2 flyby?
A: Probably not. But it is in a heliocentric orbit and could potentially make observations from that orbit of more transiting exoplanets like it did during the EPOCh phase of the mission. NASA has collected some suggestions but has not yet made a decision on how DIF might be used after the EPOXI mission.

Q: Does the Deep Impact spacecraft have some "autonomous decision making software" like the Mars Rovers Opportunity and Spirit?
A: In terms of autonomous software, we have two autonomous software packages on board the spacecraft:
1) AutoNav: This package performs real-time image analysis of images of the comet to automatically update the orbit ephemeris of the comet and allow the spacecraft to better point at it.
2) Fault Protection: This package reads all the sensors from various points on the spacecraft and figures out if there is a problem and tries to fix it. However, DIF does not have "autonomous decision-making software" ala the MERs. They can plot their own course to a target, and the path to be followed is not deterministic. Our "autonomy" is really rule-based, and not smart at all if we get into the weeds. MER can get itself out of the weeds, at least sometimes. [Thank you to Rich R. and Greg L. for answering this one!]

Q: Will you be streaming images at closest approach phase?
A: No, because of the orientation of the spacecraft relative to the Earth and comet, we can either collect images or be communicating with Earth. We opted to collect images during the closest part of the flyby, then turn and radio a bunch of images back before turning back to collect more images.

Q: Also, as the craft (correct me if I am wrong) has no plan to return to Earth, and this is the end of the mission, would it not be possible to turn IT into an impactor for 103P?
A: Without having another spacecraft nearby to observe, we would have had to rely on observations from ground-based and Earth-orbiting telescopes which simply would not have had as good a view. We would have learned something, but probably not enough to make it a viable option.

Q: What are the future plans for the Deep Impact Flyby Spacecraft after the EPOXI mission ends?
A: The spacecraft is in a heliocentric orbit. It does not have enough fuel to maneuver to any new target, but it can turn and point to make observations of various targets from the orbit it is in, much like it did during the EPOCh phase of the mission. However, the fate of the spacecraft is ultimately in NASA's hands. Any further extension of the mission still requires funding.

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