# Tag Info

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 ...

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 (...

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

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 ...

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

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

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 ...

24

There are five probes leaving the Solar System. Pioneer 10 and 11 are no longer functioning. Voyager 1 and 2 are functioning but their cameras have not been used since the early 1990s, and it is unlikely they could be reactivated. New Horizons has two camera systems. The most powerful, the LORRI system is a 20cm telescope. However, it has a key problem - it ...

23

No, absolutely none. Even assuming Pioneer 11's transceiver still works, and there's no reason to believe that, that image you attach of distances between the three probes isn't showing it proportionally correct, since it's merely an approximate slice of euclidean space and is not axially aligned with anything to correctly appreciate distances involved. So ...

20

We don't know as there's no way to calculate it exactly. To do so we'd have to have extremely accurate data on every gravitational interaction these space probes will ever be exposed to. This would require accurate information on the location, mass and vector of every single body in the galaxy, that means every star, every gas cloud, nebula, planet then all ...

18

Yes, Pioneer 10 and 11 each carried a 0.000001 megapixel camera. The single pixel was scanned over the body by the constant spin of the spacecraft in one direction and a slew of the spacecraft in the other. Building up one image took a long time, over which the relative position of the spacecraft and the body changed quite a bit, distorting the image. ...

18

We currently cannot track Pioneer 10 or 11. Someone on the XKCD forum calculated how much radiation the Voyager probes emit besides their radio transmissions. The heat they give off is emitted as infrared light: We have a power source of 420 W at 1.78×1010 km, which gives a brightness of 1×10-19 Wm-2, or an apparent magnitude of 28. That is just ...

17

I am infocat13 who wrote that unmannedspaceflight.com article, I base my opinion based on a personal communication with Dr. Stone, the PI of the Voyager project and many AIAA astrodynamics journal articles. Mr. Lasher, a JPL astrodynamics specialist, informed me of the Pioneer 11 missing its B plane Jupiter aimpoint before TCM-1, so that solid motor is ...

16

Planet Nine semi-major axis is estimated to be 400 AU to 800 AU. New Horizons is now about 50 AU away from the Sun and travels about 3 AU per year. So in about 120 years New Horizons will be 400 AU away from Sun and in 250 years 800 AU away. But Planet Nine may be at any point of its orbit. If a probe is at 600 AU, the planet may be up to 1000 to 1400 AU ...

16

It is actually pretty likely we have seen Planet 9, but just don't know that it is in fact moving. The problem is to know something is an object in the solar system, we have to see it move, and an object so far out will move very slowly. There is another way, however. That way is to image the same object from two radically different locations, especially at ...

15

Wikimedia has the following graph for the heliocentric velocities of both Pioneer probes: (SVG) As far as I can tell it's accurate, since it clearly shows the velocity change of Pioneer 10 during its Jupiter flyby on new year 1974, and Pioneer 11's two flybys of Jupiter on new year 1975 and Saturn in 1979. And New Horizons: (SVG) (This answer also has one.) ...

13

Voyager 1: separated from Centaur stage with velocity 18.3 km/s (relative to Earth, Dave Doody, Deep Space Craft: An Overview of Interplanetary Flight, 2010, page 120). Then 76.5N Injection Propulsion Unit of V1 did burn its solid fuel in 43 seconds giving additional 1,7 km/s (?), injecting the spacecraft into Hohmann transfer orbit. IPU was separated, and ...

12

Pioneers Several factors lead to the loss of signal. Radiated power: Pioneer 10's broadcast power is particularly low. 8 W at ~2.2 GHz ① Very narrow beam; the antenna gain is +65dB, which means 1/(10^6.5) the broadcast surface area... which means a pretty narrow cone. (I don't know the math for the actual beam angle.) Input power decreases - the RTGs still ...

12

I found this reference in a 2015 Reddit interview of the New Horizons team: Has the team had any success looking for Pioneer Anomaly type effects in New Horizon's position and trajectory data? Thanks for doing this AMA! Michael Vincent: We did look at that. It was attributed to the thermal radiation from the RTG pushing on the spacecraft asymmetrically on ...

12

According to NASA's history on the mission, Pioneer 11's goals included both investigation of the solar wind outside of the ecliptic, and a look at the polar regions of Jupiter, which appeared to have a more transparent atmosphere than the equatorial regions. A close flyby of Jupiter over either pole would unavoidably sling the spacecraft out of the ecliptic,...

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Pioneer 10 and 11 were built to gain experience in sending probes to the outer solar system. NASA had no experience at all of space outside Mars' orbit. The opportunity for a Grand Tour (one probe could cover all 4 of the outer planets) was recognized early enough to do some experiments. There wasn't much of a budget though, so the scientific payload was ...

11

This is propulsion via infrared photons, which is similar to other photon propulsion methods. It's more common to hear about gamma (antimatter drives) and x-ray propulsion because we have mechanisms to drive higher power through it, whereas thermal photons are limited by the Stefan-Boltzmann law. To the question: How much heat would be necessary to ...

9

It isn't known exactly, as we don't have a good way of tracking them. However, this question was brought up in the form unmannedspaceflight.com as @Hash mentioned, which mentions a Wikipedia article. Bottom line, we believe there are 11 artifacts that are leaving the Solar System that we launched: 5 probes (Pioneer 10, 11, Voyager 1, 2, New Horizons), and 4 ...

8

No. And here's why: To establish radio communication between two points in space successfully, one has to achieve the Signal-to-Noise ratio (SNR) greater than some threshold which varies depending on the type of signal modulation and error correction used. This is done through several means: Pointing the antennas' radiation patterns) of the receiver and ...

8

The Pioneer Anomaly gives a first-order answer. The Pioneer Anomaly was an acceleration of $(8.74±1.33)×10^{−10} m/s^2$. According to the paper in which the solution for the Anomaly was published, this acceleration was caused by about 50 W of heat output. So you get $10^{-11} m/s^2W$, or 100 GW for 1 $m/s^2$, for a spacecraft that weighs ~250 kg. So 40 MW ...

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