# What is the largest delta-v ever produced in space from mechanically stored energy?

The math behind this answer suggests that while the delta-v delivered from hand-throwing an object from the ISS would not produce prompt de-orbit and atmospheric reentry, it would still lower the periapsis by tens if not a hundred kilometers (depending on the flexibility of the space suit).

I humorously but quantitatively suggested that a hand-held slingshot device (not the gravitational maneuver of the same name) would be sufficient.

When satellites are deployed from their upper stages, usually some kind of small impulse ensures the separation is clean, well controlled and certain. From the video's I've seen the separation velocities are often of the order of a meter per second. I'm guessing this impulse is often produced by springs or other devices that store mechanical energy.

I'm wondering if mechanically stored energy has ever been used to produce a delta-v substantially larger than this, perhaps 5 or 10 m/s? More?

Question: What is the largest delta-v ever produced in space from mechanically stored energy?

For the purposes of this question, energy stored as a compressed gas, or phase change wouldn't count. The source of energy should be something along the lines of springs or other elastic material held under mechanical stress or rigid body phenomena. Also while I'm primarily interested in intentional events, unintentional events might also apply.

edit: since there are several comments about rotation, I'll say it explicitly that energy stored as rigid body rotation is also allowed, and two (or even a few) objects connected by a line under tension would count as a rigid body rotation as well, for the purposes of this question.

GIF from Scott Manley's video The Antares Rocket - NASA's Less Famous Ride To The Space Station showing a stored energy device imparting a delta-v between the first and second stage of an Antares rocket.

GIF

• Maybe consider changing slingshot to something like 'catapult' to avoid confusion with the gravitational assist sort? – Jack Jun 22 '18 at 8:17
• Another similar use of mechanical systems is for spin stabilization of the satellites, they release a YoYo with masses to stabilize the spin. Watch link It doesn't provide any $\Delta V$ though!! – MyTwoCents Feb 9 '19 at 10:06
• @MyTwoCents youtu.be/001IXnp0ogc and youtu.be/HCtNqD-jlPE and see Has adjustable Yo-Yo de-spin been tested or demonstrated? as well as How can a yo-yo de-spin maneuver reverse the rotation? and also How did the GoFast 2014 Rocket de-spin? If you have the rotation rate (RPM) and the rocket body diameter, you can get the velocity; go for it, I think it makes for an excellent answer. – uhoh Feb 9 '19 at 11:24
• TSS-1R flew away at around 10 m/s when its tether snapped; not sure if that counts as "mechanical energy" or not. – Organic Marble Feb 10 '19 at 3:00
• @OrganicMarble sure it counts. Two masses connected by a line under tension rotate as a single rigid body, storing energy. Unplanned disassembly releases that stored energy. I'll add rotation to the question to make it official. – uhoh Feb 10 '19 at 3:14

Space Shuttle mission STS-75 deployed a satellite on a 20.7 km tether. As the deployment neared completion at 19.7 km, the tether parted (due to a complicated chain of events starting with manufacturing defects) and the satellite flew away at a relative rate of ~ 10 m/s.

Source: TSS-1R Mission Failure Investigation Board report; the departure rate is mentioned in paragraph 3.2.2.4.

• This is interesting! I see the 10 m/s in section 3.2.2.4 . The plot suggests a tether deployment of roughly 1.7 m/s (6 km/hr) but it says "The coiled section moved away from the orbiter at an initial velocity of 3 m/s, increasing to 10 m/s, which was the satellite differential velocity. That means there's probably at least another question here somewhere. – uhoh Feb 10 '19 at 16:01
• cued at 07:13 (shot from Australia!) youtu.be/pQTMliO1JVc?t=433 – uhoh Feb 10 '19 at 16:07
• The video I linked shows it from the onboard perspective. It's just a link on a NASA page though, not on youtube, so it didn't embed. – Organic Marble Feb 10 '19 at 16:17
• For some reasons I always have problems with ksc.nasa.gov here so I can't see the mpg. I'll try it from some other locations tomorrow. – uhoh Feb 10 '19 at 16:34
• ~ 10 m/s it is then, thanks! – uhoh Jun 13 '19 at 2:23

Apollo 13

The spent S-IVB stage was intentionally guided on a collision course for the lunar surface where it experienced a change in velocity of 2.58 km/s through what could accurately be described as "rigid body phenomenon." The purpose of colliding this stage with the lunar surface was not solely as a disposal method to avoid space junk, it provided unique calibration signals for the Apollo passive seismic experiment.

Other Impactors

Apollo 13's S-IVB was not the only time a spent upper stage has been crashed into the moon in the name of science, but it is the fastest as far as I could find. Others include several of the S-IVBs and LMs from the Apollo program and the centaur used for LRO/LCROSS. I wasn't able to find any faster man made impactors (I explicitly ignored impacts through atmosphere, as that ceases to be only rigid bodies), but honestly I wasn't thorough since I don't feel like this answer keeps to the spirit of the question, given the examples provided in the OP. A potentially slightly better answer that avoids the issue with the impulse coming from a heavenly body is the Iridium 33 and Kosmos-2251 collision, which produced debris that had a change of velocity in the 100s of m/s. This is still not a satisfying answer to me though.

Apollo 14

20 m/s

It may not be anywhere as impressive as some of the other solutions, but I find it to be the most satisfying fit with the way the prompt was worded.

"Shepard brought along a six iron golf club head which he could attach to the handle of a lunar excavation tool, and two golf balls, and took several one-handed swings (due to the limited flexibility of the EVA suit). He exuberantly exclaimed that the second ball went "miles and miles and miles" in the low lunar gravity, but later estimated the distance as 200 to 400 yards (180 to 370 m)." Wikipedia

A quick projectile motion calculation gives an initial velocity for the ball of about 20m/s.

Golfing has also been done from the shuttle and ISS, but the first was putting, and the second was an intentionally slow swing.

• fyi I've just asked What's the highest velocity impact between a spacecraft and a solar system body? What about for a dedicated impactor (spacecraft component)? where I've drawn a distinction between spacecraft impacts and impactor impacts. You might like to post an answer to address one of them. – uhoh Feb 9 '19 at 0:42
• How do you define "rigid body phenomena"? – Lex Feb 9 '19 at 0:43
• Throwing objects, accelerating objects with a rubber band, would count; expelling compressed or hot gases, electrostatic acceleration of plasma would not count. en.wikipedia.org/wiki/Rigid_body I'd say using the impact of a golf club on a compressible golf ball definitely counts! – uhoh Feb 9 '19 at 0:45
• I like your answer, I don't think there's any need to modify it. I just feel that some of this research deserves a better question, so I've asked a different question and suggest that it's possible you may want to repost some of this information there as well. – uhoh Feb 9 '19 at 0:51

If pneumatic pressure counts as mechanical energy, then the winner by far is the "manhole cover in space." In 1957, a nuclear weapon was detonated at the bottom of a mine shaft with a 2,000 lb manhole cover blocking the top of it. It is unknown whether it made it out of the atmosphere or was vaporized, but if did make it out it is the fastest moving object created by mankind.

During the Pascal-B nuclear test, a 900-kilogram (2,000 lb) steel plate cap (a piece of armor plate) was blasted off the top of a test shaft at a speed of more than 66 km/s (41 mi/s; 240,000 km/h; 150,000 mph). Before the test, experimental designer Dr. Brownlee had estimated that the nuclear explosion, combined with the specific design of the shaft, would accelerate the plate to approximately six times Earth's escape velocity.[8] The plate was never found, but Dr. Brownlee believes[9] that the plate did not leave the atmosphere, as it may even have been vaporized by compression heating of the atmosphere due to its high speed.

• Even if it didn't make it out - perhaps, briefly, it was the fastest moving human-made object anyway. – Don Branson Jun 22 '18 at 18:22
• At least, from mechanical energy, and not from electromagnetic energy in the LHC. – Don Branson Jun 22 '18 at 18:23
• Was there any actual evidence of what happened or is this all just theoretical calculations of what could have happened? – Organic Marble Jun 22 '18 at 19:25
• @OrganicMarble - there is evidence that establishes a lower bound for its velocity. Specifically, a high speed camera was pointed at the site where the manhole cover was placed with the intention of tracking its movement. Sadly, it only captured the manhole cover for one frame so you can only really establish a lower bound for its speed rather than an actual velocity or a change in velocity over time. The manhole cover was never found, meaning that it likely either escaped the earth or was vaporized due to air resistance. – Justin Braun Jun 22 '18 at 20:41
• The fifties, when dreaming of nuclear powered street cars was possible. The speed of 66 km/s was not measured and the estimation might be wrong anyway. – Uwe Jun 23 '18 at 15:15