# What is the largest piece of space debris volumetrically?

What is the largest piece of space debris currently in Earth orbit by volume? Space debris is not limited to defunct satellites, but also includes things like spent upper stages.

Bonus points for biggest piece in space not orbiting Earth (is it the Roadster?)

## 4 Answers

Initial and Bonus Answer: With a volume of 609.31 M^3 and an empty mass of 15,500kg (13,500 kg empty weight plus 2,000kg for the attached Instrument Unit), J002E3 is Apollo 12's S-IVB stage (designated S-IVB-507).

It was intended to be placed in a heliocentric orbit following Apollo 12's TLI Burn. Due to insufficient propellant, however, it ended up orbiting the earth slightly outside of the moon's orbit until 2003. It then left earth's orbit and is predicted to re-enter earth orbit in the 2040's.

• This thing is on a fascinatingly weird orbit, nice find! Nov 22 '19 at 0:22
• If it leaves and re-enters orbit, is that meta-orbiting?
– Mast
Nov 22 '19 at 10:37
• @Mast I meta orbit once. It left me going in circles Nov 22 '19 at 13:28
• Since we're doing space puns, when it reenters earth's atmosphere, someone needs to write a good orbituary. Nov 22 '19 at 16:02
• Both of those puns may have damaged my orbital lobe... Nov 24 '19 at 2:40

I would say it's probably Envisat. It is definitely the heaviest although i'm not sure if it is also the largest piece volumetrically. We had a full scale 'mock up' at our faculty and I can confirm that it is absolutely massive! They have been thinking about ways to deorbit it for quite a while now since a collision involving this large of a satellite could set off a Kessler Syndrome chain reaction.

Bonus question:

The Herschel Space Observatory which is inactive and was pushed to a safe heliocentric orbit after its mission at L2 was ended. Again it's quite hard to verify that it is indeed the largest volumetrically but it is definitely bigger than the roadster.

• I'm pretty sure that the stage two the Roadster was/still is attached to is still out there, is that bigger than the Herschel Space Observatory? Nov 21 '19 at 14:44
• Heliocentric orbit means it doesn't strictly meet the OP's question. Nov 21 '19 at 14:48
• @CarlWitthoft I interpreted it as 'not in an Earth orbit'. your interpretation also rules out the roadster. Nov 21 '19 at 14:54
• @AlexanderVandenberghe maybe the question was edited? It now reads "..currently in Earth orbit..." Nov 21 '19 at 14:56
• @CarlWitthoft I clarified the phrasing Nov 21 '19 at 15:39

Answer for Bonus question

Not entirely sure if indeed the biggest (in heliocentric orbit), but bigger than roadster for sure: S-IVB, the third stage of Saturn V rocket that was used for Apollo lunar missions (height 17.81m, diameter 6.6m) https://en.wikipedia.org/wiki/S-IVB

There are few of them in heliocentric orbit. https://en.wikipedia.org/wiki/List_of_artificial_objects_in_heliocentric_orbit

After extraction of Lunar module, the S-IVB from some of the earlier missions were maneuvered to slingshot around the moon and to be sent to heliocentric orbit intentionally (S-IVB from the later missions were deliberately steered to crash onto the moon).

They were only in orbit for a few years each in the 1960s, and thus fail the "currently" test, but the Echo1 and Echo2 satellites deserve some mention. https://en.wikipedia.org/wiki/Project_Echo

Basically aluminized Mylar balloons, Echo1 had a volume of $$14,800 \text{ m}^3$$, while Echo2 topped out at $$36,000 \text{ m}^3$$

Echo2 was actually test-inflated in a dirigible shed. Hey. a balloon is a balloon, right?