Cool your jets: NASA's quantum spaceship is doubtful - space - 06 August 2014 - New Scientist

Cool your jets: NASA's quantum spaceship is doubtful - space - 06 August 2014 - New Scientist: ...as Baez points out, this new device in question wasn't even tested in a vacuum! That's extremely important; assuming the measurements are real, the thrust seen could be due to air being warmed up and moving around.

The real reason why the Pioneer spacecrafts appear to be slowing down

The real reason why the Pioneer spacecrafts appear to be slowing down: According to Sergei Kopeikin, the previous explanation for the so-called Pioneer anomaly was only able to account for 15 to 20% of the observed deceleration. Kopeikin, on the other hand, devised a new set of calculations which factored in the expansion of the universe — including the way it affects the movement of photons that make up light and radio waves.

Pioneer Spacecraft Warmth Takes Heat off Relativity

Pioneer Spacecraft Warmth Takes Heat off Relativity: Pioneer 10 and 11 are slowing down due to a small-but-ever-present thermal recoil. Both spacecraft give off heat from their electronics and from the radioactive decay of their plutonium fuel, and that’s enough to impart the measured deceleration. The researchers liken it to photons from a car’s headlights pushing gently back on the vehicle. The analysis is in the journal Physical Review Letters.

Pioneer Anomaly Solved By 1970s Computer Graphics Technique - Technology Review

Pioneer Anomaly Solved By 1970s Computer Graphics Technique - Technology Review: In particular, Phong shading has allowed the Portuguese team to include for the first time the effect of heat emitted from a part of the spacecraft called the main equipment compartment. It turns out that heat from the back wall of this compartment is reflected from the back of the spacecraft's antenna (see diagram above).

Since the antenna points Sunward, towards Earth, reflections off its back would tend to decelerate the spacecraft. "The radiation from this wall will, in a first iteration, reflect off the antenna and add a contribution to the force in the direction of the sun," say Francisco and co.

Lo and behold, this extra component of force makes all the difference. As Francisco and co put it: "With the results presented here it becomes increasingly apparent that, unless new data arises, the puzzle of the anomalous acceleration of the Pioneer probes can finally be put to rest."

The Pioneer Anomaly, a 30-Year-Old Cosmic Mystery, May Be Resolved At Last | Popular Science

The Pioneer Anomaly, a 30-Year-Old Cosmic Mystery, May Be Resolved At Last | Popular Science: Using the telemetry data, the two scientists created an extremely elaborate “finite element” 3-D computer model of each Pioneer spacecraft, in which the thermal properties of 100,000 positions on their surfaces are independently tracked for the duration of the 30-year mission. Everything there is to know about heat conduction across the spacecraft’s surfaces, as well as the way that heat flow and temperature declined over time as the power of the generators lessened, they know. The results of the telemetry analysis? “The heat recoil force accounts for part of the acceleration,” said Turyshev. They wouldn’t tell me how significant a part. (Turyshev: “We’d like to publish that in the scientific literature.”) But according to Toth, “You can take it to the bank that whatever remains of the anomaly after accounting for that thermal acceleration, it will at most be much less than the canonical value of 8.74 x 10-10 m/s2, and then, mind you, all those wonderful numerical coincidences people talk about are destroyed.