Mr. Holdridge has served as Mission Operations Manager for three missions with the Johns Hopkins University Applied Physics Laboratory (APL) including GEOSAT, NEAR, and CONTOUR mission. Mr. Holdridge has developed and refined APL's model for the conduct of low cost planetary missions. He was responsible for planning the operations concepts for placing the NEAR spacecraft into orbit around an asteroid (Eros) and conducting the subsequent one year orbital mission.

As CONTOUR Mission Operations Manager, Mr. Holdridge wrote, and is in the process of implementing, the operations concept for performing multiple Comets encounters with periods of hibernation in between for cost savings. He is also supporting the development of the operations concept of the first mission to Pluto by adapting operations concepts developed for CONTOUR encounters and hibernation and refining them for the longer term mission.

Prior to working at APL, Mr. Holdridge provided spacecraft mission analysis, control center software development, and operations management support to a variety of spacecraft missions for NASA, NOAA, the U.S. NAVY, and commercial space missions since 1983.

Mr. Holdridge received his Master's degree in Astronautics from George Washington University in 1993 and his undergraduate degree in Aerospace Engineering from the University of Maryland in 1982.

Mr. Holdridge answers some questions for us:

The Pluto Portal: What interests you about the exploration of Pluto?
Mr. Holdridge: It is the most challenging planetary flyby scenario with potential for great rewards !

The Pluto Portal: What instrument/part of the mission are you working on?
Mr. Holdridge: As Deputy Mission Director I will be most concerned with NH mission operations. I will be responsible for ensuring approaches and lessons learned from previous planetary mission operations are encorporated into the New Horizon's spacecraft design and mission operations approaches.

The Pluto Portal: What kind of engineering challenges face engineers building a spacecraft to get to Pluto?
Mr. Holdridge: The spacecraft must survive the long journey and hence must have a long life time. Also, energy must come from within given solar power is not an option so far from the Sun.

The Pluto Portal: Write your own Pluto or Kuiper Belt Question or New Horizons Spacecraft/Instrument question someone from the General Public May be interested in, and answer it!
Mr. Holdridge: What is the most challenging aspect to operating a spacecraft going to Pluto?
Mr. Holdridge: Given the long time period required to get to Pluto , keeping a knowledgeable team together capable of handling challenging operations will be a challenge. Ground systems hardware and software used to communicate with the spacecraft will be changing and we have to change with it. Finally, the Pluto encounter itself will be very challenging in that we have only one chance to get it right with long delays in communications.