39 votes
Accepted

Are the computers on Pioneer 10 & 11 still running?

There's a decent chart of RTG output on figure 2-14 of this paper. From 1985 to 2000, RTG output of Pioneer 10 fell from ~100W to ~62W as the RTGs degraded. (Radioactive material decays, thermocouples ...
TLW's user avatar
  • 743
37 votes

Could one of the interstellar probes discover Planet IX by accident?

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 ...
GremlinWranger's user avatar
37 votes

Why was radio contact with Pioneer lost earlier than with Voyager?

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 ...
Russell Borogove's user avatar
31 votes

Where will the Pioneer, Voyager and New Horizons spacecraft be after one galactic orbit?

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,...
Eugene Styer's user avatar
  • 1,852
29 votes
Accepted

Why was the imaging quality of the Voyager probes *much* better than the Pioneer probes despite being launched only 5 years later?

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. ...
Russell Borogove's user avatar
28 votes

Why was radio contact with Pioneer lost earlier than with Voyager?

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 ...
Hobbes's user avatar
  • 128k
28 votes

Why was the imaging quality of the Voyager probes *much* better than the Pioneer probes despite being launched only 5 years later?

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 ...
Mark Foskey's user avatar
25 votes

Could one of the interstellar probes discover Planet IX by accident?

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 ...
Andrew is gone's user avatar
25 votes
Accepted

Why is Voyager/Pioneer so slow compared to Parker Solar Probe?

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 ...
Jack's user avatar
  • 9,976
25 votes
Accepted

Why didn't the Pioneer probes maintain communications with Earth as long as the Voyagers have?

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 ...
Hobbes's user avatar
  • 128k
25 votes

Are the computers on Pioneer 10 & 11 still running?

In the case of Pioneer 10, it has been twenty years since the last signal was received from the spacecraft. While attempts were made to contact the craft afterwards, no answer was received. Without ...
Oscar Lanzi's user avatar
  • 8,505
21 votes

Where will the Pioneer, Voyager and New Horizons spacecraft be after one galactic orbit?

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 ...
GdD's user avatar
  • 20.3k
16 votes

Could one of the interstellar probes discover Planet IX by accident?

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 ...
Uwe's user avatar
  • 49k
16 votes

Could one of the interstellar probes discover Planet IX by accident?

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 ...
PearsonArtPhoto's user avatar
  • 121k
16 votes

What were the speeds of Pioneer 10 and Voyager 1 when Voyager overtook it in 1998?

note: I think that @PM2Ring's answer is far superior, more informative, and more accurate as well. Using JPL's Horizons I got the following state vectors in solar system barycenter coordinates (most ...
uhoh's user avatar
  • 149k
15 votes
Accepted

Are there any accurate velocity plots of all spacecraft that achieved escape velocity from the solar system? (Pioneers, Voyagers, & New Horizons)

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 ...
SE - stop firing the good guys's user avatar
13 votes
Accepted

Why was radio contact with Pioneer lost earlier than with Voyager?

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/(...
aramis's user avatar
  • 11.5k
13 votes
Accepted

What were the speeds of Pioneer 10 and Voyager 1 when Voyager overtook it in 1998?

Horizons also gives range and range-rate data in the Observer table. I used the Sun as the observation center, rather than the Solar System barycenter. On 1998-Feb-14 at midnight UTC, Pioneer 10 was ...
PM 2Ring's user avatar
  • 2,594
12 votes

Did New Horizons also demonstrate the "Pioneer Anomaly"?

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 ...
Hobbes's user avatar
  • 128k
12 votes
Accepted

Why did Pioneer 11 use a gravitational assist to swing above the ecliptic plane... twice?

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 ...
Russell Borogove's user avatar
8 votes
Accepted

When will Voyager 2 overtake Pioneer 10 as the 2nd most distant spacecraft from the Sun?

There is useful current data at Heavens Above. The relevant bit is Voyager 2 is currently (Nov 2020) 125.4 AU from the Sun travelling at 3.231 AU/year, and Pioneer 10 at 127.2 AU and 2.512 AU/yr. So ...
Steve Linton's user avatar
  • 19.6k
8 votes

Why is Voyager/Pioneer so slow compared to Parker Solar Probe?

You have probably seen funnels like the above in shopping malls. Drop a coin in the funnel and it will move slowly at the edge and move faster as it nears the center. This is a good model of a ...
HopDavid's user avatar
  • 15.8k
7 votes
Accepted

Did New Horizons also demonstrate the "Pioneer Anomaly"?

There are at least three independent models for the thermal recoil force that were applied to the Pioneer spacecraft. The results of all of them are compatible with the observed anomaly, which is a ...
Paulo Gil's user avatar
  • 330
7 votes
Accepted

How are precision trajectory measurements made of trans-Neptunian spacecraft?

Doppler and ranging are used routinely. They are both two-way, with the Doppler turning the frequency around and the ranging turning around a pseudo-noise signal. This is complicated, only for these ...
Mark Adler's user avatar
  • 58.2k
6 votes
Accepted

Is contact with Pioneer 7 or 8 still possible?

It's not impossible: The Pioneers have not been switched off (as evidenced by the later successful attempts to contact them). They're in constant sunlight so no thermal cycling which increases their ...
Hobbes's user avatar
  • 128k
6 votes

Why does the Sagan-Drake pulsar map have a circle (negative/blank) near the center?

It is explained in the original paper from Sagan: ...
Ludo's user avatar
  • 14.4k
6 votes
Accepted

Why has the Earth's motion carried it out of view of Pioneer 11's antenna?

Looking at the trajectories of the Pioneers, the wording "The Earth's motion has carried it out of the view of the spacecraft antenna" seems to be a poor choice of words. you can see that in the ...
Hobbes's user avatar
  • 128k
4 votes

Can we talk to Pioneer 6?

It's been done before: in 2014, an amateur group established contact with ISEE-3, another old space probe (launched in 1978) on a heliocentric trajectory. The main obstacles: you need access to ...
Hobbes's user avatar
  • 128k
4 votes

When will Voyager 2 overtake Pioneer 10 as the 2nd most distant spacecraft from the Sun?

Currently, PIONEER 10 is at a distance of 134.353 AU from the Sun and VOYAGER 2 is at a distance of 134.356 AU from the Sun, overtaking it at a relative speed of approximately (3.224-2.509)/365 = 0....
Piotr Wójtowicz's user avatar
3 votes

Why does the Sagan-Drake pulsar map have a circle (negative/blank) near the center?

Partial answer, exploring some details It's clearly not an artefact of the SVG vectorised file on Wikipedia. A photograph of the Voyager Golden record (which features the same map), shows the same gap....
SE - stop firing the good guys's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible