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82

New Horizons will never overtake Voyager 1. Although New Horizons is currently faster than any other man-made object, it won't be by the time it reaches the outer corners of the solar system. From the John Hopkins University/Applied Physics Laboratory New Horizons page: Though New Horizons will also reach 100 AU, it will never pass Voyager 1, because ...


74

Voyager 1 was the first to reach Jupiter and the first to reach Saturn, as it was launched on a "shorter and faster trajectory" (Wikipedia, NASA). So the numbering was chosen to reflect the order of the main part of the mission, not the launches. I have not found any sources explicitly stating that as the reason, but the arrivals at Jupiter and Saturn ...


64

It's the gravitational attraction of the Sun. Voyager is moving away from the Sun and is pulled back by its gravity. Since Voyager is not moving directly away from the Sun, it's trajectory also curves.


61

No, not even slightly. Neither Voyager has much fuel left; in fact, they don't have much fuel even for changing their attitude (the way they point), which is orders of magnitude less fuel than for making major course changes, and the course change necessary to return to Earth is so large it would never have been possible in any case: both probes used gravity ...


49

The trajectory was not only "unhindered" - it was enhanced! Knowing mass of the planet you can calculate very precisely how the trajectory of a probe flying by will be affected. You modify the trajectory on arrival in such a way, that the departure trajectory will be exactly as desired. And due to some rather unintuitive physics caveats, you can make it so ...


46

Here's a nice graph of Voyager 2's speed, and the difference made by the gravitational assists: You can see that the probe slowed down between assists. New Horizons would follow a similar graph, but with fewer assists its speed will end up below Voyager 2's, as @gerrit said.


46

why weren't they completely attracted by their gravitational field? How much a trajectory is changed, depends on 3 factors: the mass of the planet, the speed of the spacecraft, the distance between spacecraft and planet Voyager's speed and distance were chosen to make sure Voyager wouldn't enter orbit around the planet. Voyager's speed before approaching ...


43

The mission was to fly by the outer planets. Once it got to Neptune that mission was complete. From Wikipedia: Because this was the last planet of the Solar System that Voyager 2 could visit, the Chief Project Scientist, his staff members, and the flight controllers decided to also perform a close fly-by of Triton, the larger of Neptune's two originally ...


38

Communication system: The radio communication system of Voyager 1 was designed to be used up to and beyond the limits of the Solar System during the extremely long flight of this space probe. The communication system includes a 3.7 meter diameter parabolic dish high-gain antenna to send and receive radio waves via the three Deep Space Network ...


38

From the Voyager FAQ Question: Can the Voyager imaging cameras be turned back on? Answer: It is possible for the cameras to be turned on, but it is not a priority for Voyager's Interstellar Mission. After Voyager 1 took its last image (the "Solar System Family Portrait" in 1990), the cameras were turned off to save power and memory for the ...


37

Interplanetary communication is mainly dependent on signal strength (for transmission) and antenna size (for reception). The Pioneers use a 9-foot antenna and an 8-watt transmitter. The Voyagers use a 12-foot antenna and a 20-watt transmitter, allowing a substantially stronger signal to be received on Earth.


37

Any hypothetical planet (or other object) even further out would be very dark, so few photos are taken for any reason other than to look inward. (And in any case, the cameras on the Voyagers are shut down due to lack of power.) So discovery by camera would be very unlikely. What would trigger a discovery would be deviation of trajectories from those ...


36

They wanted a close flyby of Triton. Triton's orbit is at a large angle to the ecliptic plane, and Triton was below Neptune at the time of Voyager's flyby, so they needed a course change that pointed "down" from Neptune. From the Voyager Neptune travel guide (large PDF), page 118-119 of the PDF (page number 107-108 indicated on the page): However, ...


34

Additionally, the probe has just passed a large planetary body with its own gravity well. The probe has to climb up out of that planet's gravity well which costs momentum. There is a net gain in momentum overall, the probe is leaving with more momentum than it entered the slingshot manoever, but the highest velocity is about where the probe is moving ...


33

In 2015, the last original Voyager engineer still on the project, retired. NASA specified that his replacement would have to know FORTRAN. The software was updated regularly after launch: The last true software overhaul was in 1990, after the 1989 Neptune encounter and at the beginning of the interstellar mission. "The flight software was basically ...


32

Voyagers are still active, and albeit they don't have the power required to run all the scientific equipment onboard and some of it stopped working by now, they still transmit telemetry data streams towards the Earth that is picked up by NASA JPL's 70-meter antenna at Goldstone, California, part of the Deep Space Network. Quoting from Wikipedia on Voyager ...


32

Oversimplifying by taking the current velocity of each probe and multiplying it by 250 million years, I get: Voyager 1 - 10,000 light years away Voyager 2 - 9,600 light years away New Horizons - 9,300 light years away Pioneer 10 - 7,800 light years away Pioneer 11 - 7,000 light years away Admittedly this ignores slowing down due to the sun's gravity (...


31

But if some space debris comes on its way or any of the extra planetary objects comes on its way then how it changes its path? Not only won't Voyager 2 change it's path, it can't change it's path. Suppose you drop your cellphone from the top of a tall building. Your cellphone is going to fall and hit the ground, hard. Your cellphone has no sensors to ...


29

No, it's not feasible. The fundamental problems that prevent this are: The Pioneers do not have enough power to operate the transmitter, due to corrosion of the thermocouples The Voyagers and Pioneers, even at full power, use very low power transmissions The Pioneers would need to be able to receive and obey instructions to aim for a Voyager The craft are ...


29

You are correct that Voyager did not change from above escape velocity to below escape velocity shortly after launch. The plot is misleading in that it is just not very accurate right there at 1 AU. The plot lines are kind of thick and a smidge off. Now that I look at it more closely, the escape velocity line in that plot is wrong in other places as well. ...


29

The 1960s and 1970s were a period of rapid technological development, so it's not actually surprising that the relatively new field of electronic imaging advanced so far in that five-year period. Especially for spacecraft applications, where you have severe power and weight constraints and a harsh operating environment, compromises had to be made in quality -...


28

In addition to a better transmitter, the Voyagers have better power reserves: their RTGs supplied 470 W at launch, while the Pioneer RTGs supplied 160 W at launch. So the Voyager RTGs will take much longer to decay to a point where they can't power the spacecraft. NASA seems to think RTG decay is the primary reason we can't receive Pioneer 10 any more: ...


28

It is not only the progress in imaging over that period. Voyager was a more ambitious and expensive mission in general. The mass of Pioneer 11 was 259 kg, while that of Voyager was 825.5. That extra mass included a proper camera with multiple lenses on a steerable platform. This is different from the Pioneer spacecraft, which were spin-stabilized. The ...


27

Space is almost completely empty. The voyager probes are exceedingly unlikely to collide with anything (as demonstrated here: What is the possibility of Voyager 1/2 colliding with matter (Asteroids or planetoids) present in space?) larger than a mote of dust. If they did collide with anything at 15 km/s, then it slowing them down would be the least of their ...


27

Most likely no. Voyager downlink communication (via its radio link to NASA's Deep Space Network (DSN) is not continuous. You can check the contact schedule at this Voyager site. If everything looks fine during one DSN contact period, and then at the next contact period there's no signal at all, there are myriads of possible causes, ranging from failure of ...


25

The initial plan was to visit all of the outer planets: The Planetary Grand Tour was to send several pairs of probes to fly by all the outer planets (and Pluto) along various trajectories, including Jupiter-Saturn-Pluto and Jupiter-Uranus-Neptune. Limited funding ended the Grand Tour program, but elements were incorporated into the Voyager Program, which ...


25

They did not ! This is the trajectory of Voyager 1 at Jupiter. credits wikipedia


25

Why the Pioneers didn't last as long: The Pioneers were a low-budget mission just to test if flying to the outer planets was feasible They used a smaller radio transmitter (8 W vs. 23 W) and antenna (2.7 vs 3.6 m diameter) so their signals are weaker The Pioneers used a smaller, earlier design Radioisotope thermoelectric generator as their power source (...


25

Physical First and foremost, the physical reason is that objects accelerate as they approach massive bodies and decelerate as they recede: Parker Solar Probe achieves its peak orbital speed (almost 200 km/s eventually) at its closest approaches to the Sun - as it falls inwards towards the Sun on each orbit it speeds up then slows down again on the way back ...


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