Anne VerbiscerMay 23, 2014

The value of a Guest Investigator program for Dawn

Editor's note: Since last year, there have been many questions in the planetary science community about whether there will be a Participating Scientist program for the Ceres encounter phase of the Dawn mission. I thought this was an important topic so I asked Anne Verbiscer to explain what Participating Scientists are, how they would contribute to the Dawn mission, and the current status of a Participating Scientist program for Ceres. I thank Anne for explaining this to The Planetary Society Blog's readers! -- ESL

I have been extremely fortunate to have joined the Cassini mission as a Participating Scientist. I relished the opportunity to learn firsthand how a large mission functions and how different instrument teams and disciplines interact to coordinate the acquisition and analysis of science from the Saturn system. Cassini Participating Scientists have led many recent Cassini discoveries. For instance, Participating Scientist Matt Hedman led the discovery of the connection between Enceladus’ plume activity and its orbital position, and Jason Barnes reported the possible first detection of waves on one of Titan’s lakes.

Participating Scientist programs have been a win-win for both NASA missions and the scientists fortunate enough to have written successful proposals to these programs. The missions expand their pool of expertise from which they can draw to interpret data acquired by the spacecraft. The scientists, particularly younger ones, gain valuable experience as team members of a NASA mission. In many cases, NASA missions were first selected when potential Participating Scientists were still in high school, or even younger than that. Dawn was selected by NASA in 2001. There is a rich cadre of young scientists who specialize in asteroid studies and received their Ph.D.s since 2001.

NASA selected 21 Participating Scientists to join the Dawn team in 2010, prior to Dawn's arrival at Vesta in 2011. Since that time, Dawn Participating Scientists have made enormous contributions to the mission. Participating Scientists became full members of the Dawn science team, which means they participated in and contributed to internal discussions of the interpretation of data. Unlike scientists outside the mission, Participating Scientists have access to data as soon as they are ready for analysis after downlink from the spacecraft; they do not have to wait for Dawn data be made public via the Planetary Data System before they can begin using them. Therefore, the Dawn Participating Scientists have, as they should, put their privileged access to data to good use by publishing papers, presenting their analyses at science conferences, etc. Many write blogs on the Dawn mission website. This past February, the Lunar and Planetary Institute hosted a major scientific workshop: Vesta in the Light of Dawn: First Exploration of a Protoplanet in the Asteroid Belt. The workshop was convened by Paul Schenk, a Dawn Participating Scientist, and two other Dawn Participating Scientists were on the scientific committee.

Sadly, this appears to be the end of the road for these Participating Scientists. At the time that selections were made for Participating Scientists for Dawn’s exploration of Vesta, NASA intended to issue a similar call for proposals for Participating Scientists for Dawn’s exploration of Ceres, one or two years prior to Dawn’s arrival at Ceres in early 2015. Like the Dawn@Vesta Participating Scientists, the Dawn@Ceres Participating Scientists would be drawn from a pool that includes many who have entered the field since 2001. But at the Small Bodies Assessment Group (aka SBAG) Meeting on January 8, 2014, NASA officials announced that there will be no Participating Scientist Program for the Dawn mission when the spacecraft reaches Ceres next year. (Source: Page 22 in this PDF presentation by Jonathan Rall.)

A Dawn@Ceres Participating Scientist opportunity is particularly appropriate for the Dawn mission because Vesta and Ceres are quite distinct geologic worlds! Vesta has a basaltic surface which sustained a substantial impact, creating the large Rheasilvia crater at its south pole. Ceres, however, has a surface which shows similarities to those of icy satellites of the giant planets. Ceres is also considerably larger than Vesta and is classified as a dwarf planet by the IAU. So Dawn’s Ceres campaign is the first exploration of a dwarf planet, with New Horizons’ exploration of Pluto later in 2015 being the second. 2015 is certainly the Year of the Dwarf Planet!

Instead of a Participating Scientist program, NASA planned to create the “Dawn Focused Research and Analysis Program” (or DFRAP) to “perform preparatory research for and then during the Ceres campaign.” Details of the genesis of the DFRAP can be found here (PDF).

According to the description of the DFRAP program, the DFRAP Principal Investigator would not have access to proprietary data from the Ceres campaign, and would not join the Dawn Science Team as Dawn@Vesta Participating Scientists have. The Small Bodies Assessment Group has lobbied hard to ensure there will be a Dawn@Ceres Participating Scientist program, and Jim Green, head of NASA’s Planetary Science Division promised that he would review the DFRAP program.

On Friday, however, we heard that the proposed Dawn Focused Research and Analysis Program has been cancelled. The new plan is for it to be replaced with a Guest Investigator program focused narrowly on "jets and plumes" at Ceres. Hopefully, potential Dawn@Ceres Guest Investigators will be added to the Dawn team and be welcome to participate in team meetings, internal team discussions and telecons, and assist in the initial scientific analysis of data from Ceres.

Bureaucratic details aside, we need to remember why we're sending missions to places like Ceres in the first place -- to make scientific discoveries.  The issue is not whether great science will be done but whether the opportunity for a unique experience for young scientists will be missed.  Broad participation in a Guest Investigator program for Dawn helps train the next generation of planetary explorers by increasing the pool of scientists with actual mission experience that they can then bring to future missions.

Dawn thrusting toward Ceres
Dawn thrusting toward Ceres Artist's rendition of Dawn thrusting with its ion propulsion system as it approaches Ceres in 2015.Image: NASA / JPL-Caltech

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