1. The Mariner 10 mission to Mercury Presentation by: Antonio Solazzi Images taken from wikipedia.com and nasa.gov Based on the book Exploring Mercury by Robert G. Strom and Ann L. Sprauge

2. Launched 11/3/73 Arrived at Venus 2/5/74 Arrived at Mercury 3/29/74 2 nd pass by Mercury 9/21/74 3 rd pass by Mercury ? Mission ended 3/24/75

3. A historic mission The Mariner 10 mission contained many notable and historic firsts and lasts: It was the first mission to use several navigation techniques such as the “gravitation sling shot” and “Solar Sailing”. It was the first the first mission to visit Mercury. The mission was also the last use of the Mariner design and, until recently, the only mission which had visited Mercury.

4. The design and payload

5. The Mariner 10 probe was designed with seven missions/experiments in mind: TV imaging Infrared radiometry Ultraviolet spectroscopy Magnetic field detection Plasma science Charged Particles Radio Science

6. Timeline: Launch The probe was launched on November 3 rd 1973. Shortly after launch its systems were turned on for testing and calibration. During this testing the probe took the first picture of earth taken from beyond the orbit of the moon.

7. Timeline: Early problems Shortly after launching Mariner 10 began to experience the first of many problems that would plague the mission During the initial calibration test problems were encountered with the gyro system which suggested problems with the onboard power supply. The primary power supply would soon fail, leaving the probe to finish its mission using its backup system. A few weeks later, the high-gain transition antenna failed, possibly due to a crack which formed due to cold. Though this problem eventually fixed itself when the antenna warmed up, the problem would reoccur later in the mission.

8. The Venus flyby On February 5 th the probe made its closest approach to the planet Venus. The probe took over 4000 pictures of cloud patterns and atmospheric structures.

9. Timeline: Problems inroute Shortly after leaving Venus the probe’s star tracker lost its lock on Canopus. The probe automatically reacquired the star but in doing so used up a significant chunk of its maneuvering gas. This problem occurred more frequently as the probe approached the sun. In an effort to preserve the probes ability to maneuver, photons from the sun were deflected off the craft’s solar panels. By changing the angle of the solar panels the probe could change its orientation, thus saving fuel. This technique became known as solar sailing

10. The first encounter On March 29 th the probe made its closest approach to Mercury

11. Initial results Initial results from the images and data revealed a heavily cratered surface Surprisingly the probe also detected evidence of a magnetic field around the planet

12. Timeline: direction of the second pass Shortly after the first pass was made the probe again started to experience problems. The probe was running on its backup power system and was experience an unexpected power drain. It also was critically low the gas used for maneuvering the probe. The tape recorder used to store images for later transmission also failed, leaving the probe unable to store any data in the event of an antenna failure. With the possibility that only one more pass could be made, the science teams debated as to whether to dedicate the second pass of Mercury to further imaging or an investigation of the unexpected magnetic field. Since each experience required the probe to pass the planet at a different distance, only one could be realistically attempted. A final decision was eventually made to peruse imaging on the second pass.

13. The Second encounter On September 21th the probe made its second flyby. Further imaging work was done expanding the available images to 75% of the lighted side of the planet.

14. Timeline: Yet more problems Shortly before the third encounter with mercury the probe again experience technical problems. The probe’s navigational lock on Canopus was lost again, causing the probe turn at such an angle that its main antenna could no longer communicate with earth. The probe has already lost its ability to record data so if contact was not regained the probe would be unable to transmit any data on its 3 rd pass. Only the deep space tracking network had antennas strong enough to transmit an order for the probe to reacquire Canpous. Unfortunately, these antennas were already in use communicating with other probes. A spacecraft emergency was declared and the DSTN was used to order the probe to reacquire Canpous. The order was successful and the probe regained contact with earth in time to transmit data from the 3 rd pass.

15. The Third encounter The probe successfully made its 3 rd pass shortly after regaining communication with earth. During this pass evidence was detected to indicate that Mercury did in fact possess a magnetic field generated by the planet.

16. Timeline: Communication is lost On March 24 th 1975 the probe used up the last of its maneuvering gas and started to spin, ending contact with earth permanently. Beyond all expectation the probe has managed to make three passes with Mercury and made invaluable contributions to our understanding of the planet including detailed imagery, atmospheric information and the detection of a magnetic field.

17. Conclusion Beyond all expectation the probe had managed to make three passes with Mercury and made invaluable contributions to our understanding of the planet including detailed imagery, atmospheric information and the detection of a magnetic field around the planet.