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As of this month, the US satellite Vanguard I has spent 60 years in orbit and it remains the oldest man-made object in space. Vanguard I was the fourth satellite launched into orbit -- following the USSR's Sputnik I and II and the US' Explorer I. But none of the first three remain in orbit today and though Vanguard I can't send signals back to Earth anymore, it's still providing valuable data for researchers.
The first two attempts to launch the first Vanguard satellite failed, but on March 17th, 1958, Vanguard I was successfully placed into orbit. It was manufactured by the US Naval Research Laboratory (NRL), which published a lookback this week honoring the satellite's 60 years of service, and was part of a project that aimed to study Earth's geophysical phenomena from space. The Vanguard Project was established as part of the US contribution to the International Geophysical Year -- a multi-national effort to study geophysical phenomena during a period of time when the sun's sunspot activity would be at a peak.
Once in orbit, Vanguard I began collecting a trove of data. "Vanguard's orbital data proved invaluable toward the understanding of upper atmospheric physics, geodesy, geodynamics, solar terrestrial relationships, dynamical astronomy and exospheric structure," said the NRL. "Additionally, Vanguard I returned a wealth of information on air density, temperature ranges and micrometeorite impacts as well as revealing that the earth is slightly pear-shaped rather than round."
Vanguard I was the first satellite with solar electric power and while its batteries lasted just 20 days, its solar cells kept the satellite powered for seven years. Vanguard I stopped sending signals back to Earth in 1964, but since then, researchers have still used it to glean insight into how the sun, moon and Earth's atmosphere affect orbiting satellites.
Source: https://www.engadget.com/2018/03/16/vanguard-i-six-decades-orbit-oldest-man-made-object/
(Score: 2) by martyb on Monday March 19 2018, @12:22AM (3 children)
Sixty years in orbit is a long time. To maintain orbit, spacecraft have to travel pretty fast, or else they fall back to Earth.
So... how far has it travelled?
Orbital calculations are not my bailiwick. I'm hoping a fellow Soylentil can help out.
I did find this resource: http://www.n2yo.com/satellite/?s=00005 [n2yo.com] for Vanguard I and it reports:
See, also, the page on Wikipedia [wikipedia.org] for more orbital information.
To simplify the question, as the craft is still going round and round... How far did Voyager I travel over the course of its first 60 years?
Wit is intellect, dancing.
(Score: 0) by Anonymous Coward on Monday March 19 2018, @03:32AM
150 million km or so?
(Score: 5, Informative) by stormwyrm on Monday March 19 2018, @06:14AM (1 child)
Here's an approximate calculation, assuming the orbit to be elliptical. According to your Wikipedia link it has a semi-major axis (a) of 8620 km and an eccentricity (e) of 0.1844061, so the circumference of its orbit is 4aE(e) where E(e) is the complete elliptic integral of the second kind [casio.com]. So we get an orbital circumference of 4(8620)(1.55735598) = 53,700 km. With the orbital period of 132.7 minutes as per the n2yo.com link you provided, it thus has an average orbital velocity of 6.745 km/s. The satellite was launched on March 17, 1958, at 12:15:41 UTC, which is around 1,893,606,261 seconds ago as of this writing. At the orbital velocity computed, it has thus travelled some 1.277×1010 km since launch. Voyager 1, in contrast, is today about 2.11×1010 km away, almost twice as far, even though it's been in space for only 40 years, because it's moving at more than twice the speed, 17.043 km/s.
Numquam ponenda est pluralitas sine necessitate.
(Score: 2) by martyb on Monday March 19 2018, @11:17AM
Wish I could upmod you more! Not only did you provide the answer, you provided the derivation, too. Much obliged!
Wit is intellect, dancing.