Dr. Shyam Bhaskaran, JPL, NASA
- Published on 30 April 2015
Dr. Shyam Bhaskaran
Navigation and Mission Design Section, JPL, NASA
Dr. Bhaskaran received a B.S. and M.S. from the University of Texas at Austin, and a Ph.D from the University of Colorado in 1991. He has been with the Navigation and Mission Design Section at JPL for 11 years. He began his profession as a orbit determination authority on the Galileo mission. From that point forward, he has served as an member of the navigation group for a missions like Deep Space-1, Mars Odyssey, and as the navigation lead for the European Mars Express and JPL's MRO missions.
He was one of the important architects of the autonomous navigation framework utilized on Deep Space-1, and he was navigator and member of the imaging science group for the STARDUST mission. He is presently a part of NASA's Outer Planets Navigation Group at the Jet Propulsion Laboratory in Pasadena, California. He is additionally leading a group which is navigating a rocket to Comet Hartley-2.
Q1. What were the difficulties you confronted during orbit determination for Galileo mission?
The primary difficult was the loss of the X-band antenna on the spacecraft, resulting in having to use the lower strength S-band antenna, for navigation. This resulted in noisier data more affected by atmospheric effects corrupting the signal. Also, this reduced the amount of data the spacecraft could transmit, resulting in fewer optical images being downlinked for us to analyze.
Q2. How did you recreated the keplerian components for Galileo mission?
Once the spacecraft Cartesian state is known (3 components of position and 3 components of velocity), we use the standard computations found in orbital mechanics textbooks to obtain the Keplerian elements.
Q3. How was your experience in ISTRAC and ISRO satellite center in Bangalore during chandrayaan-1?
My experience at ISTRAC were excellent (I did not get a chance to go to the ISRO satellite center, only ISTRAC). It was very exciting to be there for the launch of India’s first mission beyond Earth orbit. I was impressed with the dedication of the personnel who worked on the mission there.
Q4. Please tell us something about Nail gnawing landing which was executed for crushing comet Tempel-1
The impact of Deep Impact with Tempel 1 was very exciting. We were not sure if the impactor using autonav would work properly, so everyone was very tense. When we received the signal showing the impact, we were quite ecstatic, and relieved that our hard work payed off.
Q5. Please give us more details about autonav and state some common examples of orbit changes by it?
Autonav is an on-board navigation software which uses images of an asteroid or comet so the spacecraft can determine its own orbit. It was used on several missions, including Deep Space 1, Stardust, Deep Impact, Stardust NExT, and EPOXI. Each used autonav to adjust its position by several 10s of km different than the best ground based navigation. This was critical because the close approach images, and the impact of DI, could not have been accomplished without it.
Q6. How will you define an asteroid and comet from your experience?
I don’t know what the official definition of asteroid and comet is. I simply use the same terms that scientists use, so if they say something is a comet, we call it that also. My experience doesn’t really matter for this.
Q7. Please specify some freeware tool available for orbit determination and asteroid image processing
I am not aware of any freeware tools for orbit determination. There is a commercial software you can buy called STK from AGI Solutions. For asteroid image processing, you can use some free version of Photoshop or other similar kinds of tools.