Tonight's Sky
Sun
Sun
Moon
Moon
Mercury
Mercury
Venus
Venus
Mars
Mars
Jupiter
Jupiter
Saturn
Saturn

Tonight's Sky — Change location

OR

Searching...

Tonight's Sky — Select location

Tonight's Sky — Enter coordinates

° '
° '

Has NASA kept track of the orbits of the Mariners and Rangers that missed the Moon? Do they know where they are and if they would return to Earth?

Calvin Remmers, Pierz, Minnesota
RELATED TOPICS: SPACECRAFT
Mariner spacecraft
The world’s space agencies do not actively track defunct spacecraft — that is, spacecraft with dead radios — beyond Earth orbit, though sometimes they can work out where they should be. The problem is, a spacecraft in solar orbit is almost always too small to observe and things can happen that can change its course. For example, if it includes a pressure vessel — say, a propellant tank — that has not been intentionally depressurized, there’s a good chance it has by now burst or vented. That means it acted like a rocket and changed the spacecraft’s course. Sunlight, solar wind, and even peeling paint can nudge a spacecraft’s course over decades.

Astronomy magazine subscribers can read the full answer for free. Just make sure you're registered with the website.

Already a subscriber? Register now!

Registration is FREE and takes only a few seconds to complete. If you are already registered on Astronomy.com, please log in below.
ADVERTISEMENT

FREE EMAIL NEWSLETTER

Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. View our Privacy Policy.

ADVERTISEMENT
ADVERTISEMENT
Apollo_RightRail

Click here to download a FREE Apollo PDF curated by Astronomy magazine.

Find us on Facebook