The Incredible Story of How the Huygens Mission to Titan Succeeded When It Could Have Failed
Twelve years ago today, the Huygens probe landed on Titan, marking the farthest point from Earth any spacecraft has ever landed. While a twelfth anniversary may be an odd number to mark with a special article, as we said in our previous article (with footage from the landing), this is the last opportunity to celebrate the success of Huygens before its partner spacecraft Cassini ends its mission on September 15, 2017 with a fateful plunge into Saturn’s atmosphere.
But Huygens is also worth celebrating because, amazingly, the mission almost failed, but yet was a marvelous canada goose outlet new york success. If not for the insistence of one ESA engineer to complete an in flight test of Huygens’ radio system, none of the spacecraft’s incredible data from Saturn’s largest and mysterious moon would have ever been received, and likely, no one would have ever known why.
The first ever images of the surface Titan, taken by the Huygens probe. Image Credit: ESA/NASA/JPL/University of ArizonaAs I detail in my new book «Incredible Stories canada goose outlet ontario From Space: A Behind the Scenes Look at the Missions Changing Our View of the Cosmos,» in 1999, the Cassini orbiter and the piggybacking Huygens lander were on their way to the Saturn system. The duo launched in 1997, but instead of making a beeline for canada goose outlet online the 6th planet from the Sun, they took a looping path called the VVEJGA trajectory (Venus Venus Earth Jupiter Gravity Assist), swinging around Venus twice and flying past Earth 2 years later.
While all the flybys gave the spacecraft added boosts to help get it to Saturn, the Earth flyby also provided a chance for the teams to test out various systems and instruments and canada goose outlet get immediate feedback.
«The European group wanted to test the Huygens receiver by transmitting the data from Earth,» said Earl Maize, canada goose outlet eu Project Manager for the Cassini mission at JPL, who I interviewed for the book. «That’s a great in flight test, because there’s the old adage of flight engineers, ‘test as you fly, fly as you test.'»
canada goose coats on sale The way the Huygens mission would work at the Saturn system was that Cassini would release Huygens when the duo approached Titan. Huygens would drop through Titan’s thick and obscuring atmosphere like a skydiver on a parachute, transmitting data all the while. The Huygens probe didn’t have enough power or a large enough dish to transmit all its data directly to Earth, so Cassini would gather and store Huygens’ data on board and later transmit it to Earth. canada goose coats on sale
canada goose clearance sale Boris canada goose uk site Smeds was head of ESOC’s Systems and Requirements Section, Darmstadt, Germany. So he proposed a test during the 1999 Earth flyby. canada goose clearance sale
canada goose coats Maize said that for some reason, there was quite a bit of opposition to the test from some of the ESA officials, but Smeds and Claudio Sollazzo, Huygens’s ground operations manager at ESA’s European Space Operation Centre (ESOC) in Darmstadt, Germany were insistent the test was necessary. canada goose coats
canada goose NASA’s Deep Space Network is responsible for canada goose outlet in canada communicating with spacecraft. Pictured is the Goldstone facility in California, one of three facilities that make up the Network. Image: NASA/JPL»They were not to be denied,» Maize said, «so they eventually got permission for the test. The Cassini team organized it, going to the Goldstone tracking station [in California] of the Deep Space Network (DSN) and did what’s called a ‘suitcase test,’ broke into the signal, and during the Earth flyby, Huygens, Cassini and Goldstone were all programmed to simulate the probe descending to Titan. It all worked great.» canada goose
Except for one thing: Cassini received almost no simulated data, and what it did receive was garbled. No one could figure out why.
canadian goose jacket Six months of painstaking investigation finally identified the problem. The variation in speed between the two spacecraft hadn’t been properly compensated for, causing a communication problem. It was as if the spacecraft canada goose outlet london were each communicating on a different frequency. canadian goose jacket
Artist concept of the Huygens probe descending to Titan. Credit: ESA.»The European canada goose outlet winnipeg team came to us and said we didn’t have a mission,» Maize said. «But we put together ‘Tiger Teams’ to try and figure it out.»
buy canada goose jacket cheap The short answer was that the idiosyncrasies in the communications system were hardwired in. With the spacecraft now millions of miles away, nothing could be fixed. But engineers came up with an ingenious solution using a basic principal known as the Doppler Effect. buy canada goose jacket cheap
The metaphor Maize likes canada goose outlet uk sale to use is this: if you are sitting on the shore and a speed boat goes by close to the coast, it zooms past you quickly. But that same boat going the same speed out on the horizon looks like it is barely canada goose jacket outlet moving.
«Since we couldn’t change Huygens’ signal, the only thing we could change was the way Cassini flew,» Maize said. «If we could move Cassini farther away and make it appear as if Huygens was moving slower, it would receive lander’s radio waves at a lower frequency, solving the problem.»
Canada Goose sale Maize said canada goose outlet black friday sale it took two years of canada goose discount uk «fancy coding modifications and some pretty amazing trajectory canada goose shop uk computations.» Huygens’ landing was also delayed two months for the new trajectory canada goose outlet phone number that was needed overcome the radio system design flaw. Canada Goose sale
Additionally, with Cassini needing to be farther away from Huygens than originally planned, it would eventually fly out of range to capture all of Huygens’ data. Astronomers instigated a plan where radio telescopes around the world would listen for Huygens’ faint signals and capture anything Cassini missed.
canada goose clearance Huygens was released from the Cassini spacecraft on Christmas Day 2004, and arrived at Titan on January 14, 2005. The probe began transmitting data to Cassini four minutes into its descent through Titan’s murky atmosphere, snapping photos and taking data all the while. Then it touched down, the first time a probe had landed on an extraterrestrial world canada goose outlet shop in the outer Solar System. canada goose clearance
Canada Goose Parka Because of the communication problem, Huygens was not able to gather as much information as originally planned, as it could only transmit on one channel instead of two. But amazingly, Cassini captured absolutely all the data sent by Huygens until it flew out of range. Canada Goose Parka
Canada Goose Jackets «It was beautiful,» Maize said, «I’ll never forget it. We got it all, and it was a wonderful example of international cooperation. The fact that 19 countries could get everything coordinated and launched in the first place was pretty amazing, but there’s nothing that compares to the worldwide effort we put into recovering the Huygens mission. From an engineering standpoint, that might trump everything else we’ve done on this mission.» Canada Goose Jackets
canada goose black friday sale The view of Titan from the descending Huygens spacecraft on January 14, 2005. The data has been invaluable for understanding this unique and mysterious moon, showing geological https://www.canadagoose-jackets-online.com and meteorological processes that are more similar to those on the surface of the Earth than anywhere else in the Solar System. ESA has details on the top discoveries by Huygens here. canada goose black friday sale
buy canada goose jacket Noted space journalist Jim Oberg has written several detailed and very interesting articles about the Huygens’ recovery, including one at IEEE Spectrum and another at The Space Review. These articles provide much canada goose factory outlet vancouver more insight into the test, Smeds’ remarkable insistence for the test, canada goose outlet 80 off the recovery work that was done and the subsequent success of the mission. buy canada goose jacket
Canada Goose Outlet As Oberg says in IEEE Spectrum, «Smeds continued a glorious engineering tradition of rescuing deep space missions from doom with sheer persistence, canada goose outlet uk insight, and lots of improvisation.» Canada Goose Outlet
canada goose store A modest Smeds was quoted by ESA: «This has happened before. Almost any mission has some design problem,» says Smeds, who says he’s worked on recovering from pre and post launch telecom issues that have arisen with several past missions. «To me, it’s just part of my normal work.» canada goose store
Canada Goose online For more stories about Huygens, Cassini and several other current robotic space missions, «Incredible Stories From Space» tells many behind the scenes stories from the amazing people who work on these missions. Canada Goose online
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canada goose deals This is actually a hurdle modern communications networks have to clear just using satellites in Earth orbit. The modems we use account for this drift track the the amount of difference between the expected frequency that which is received by using one or more of a number of mechanisms, including signal patterning, packet formatting, software based frequency adjustment algorithms so on canada goose deals.