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when i first heard about this probe last week i was wondering, isn't this thing old and unique enough to warrant a mission to rescue and preserve it? combined with todays lower prices for a space flight, it might just be worth it.

and now it looks like it might just survive anyways. but then according to the article there also seems to be a second (identical?) model. so maybe it's not that important, except for maybe material analysis what does 50 years of exposure to space do to the material.






I would guess that the most expensive part of such an endeavor wouldn't be the launch; it would be developing and building a spacecraft capable of capturing it and bringing it back.

Even the Space Shuttle wasn't necessarily a perfect fit for the job as-is. Hubble was serviced many times, but it was specifically designed for on-orbit capture and servicing by the Shuttle. Before they decommissioned the shuttle they actually had to install an extra piece of hardware to make it feasible to capture and de-orbit using future non-crewed spacecraft. And even then that's just to make sure it crashes in a safe place, not to bring it home intact.

There was also a mission to service a satellite that wasn't designed for the purpose, and they had a really hard time capturing it and very nearly had to give up after days' worth of failed attempts. It finally took simultaneous EVA by three astronauts to coordinate a successful capture (one to grab it by hand, two to get it onto a specialized adapter rig built just for that satellite so that the Canadarm could hold it), which is quite a thing considering that the Shuttle's only designed to allow two people on EVA at a time.

This craft is likely tumbling, which I presume would make it unacceptably dangerous for a crewed mission (and certainly rules out anyone just going out there and grabbing it with their hands), in addition to making successful capture that much more difficult.


Is this one of the missions where the shuttle returned a satellite from orbit? There were a few:

https://rammb.cira.colostate.edu/dev/hillger/Shuttle-related...


Wouldn't it be possible to "simply" match it's tumble?

No, when it tumbles, it does it around its centre of mass. You'd have to get a craft that has empty area inside.

If you know Elite, it has space stations where you dock by going inside, while matching station's rotation. That's only in one axis (and note the hangar goes through the axis of rotation, i.e. centre of mass). To add rotation around another axis would make the task impossible.


It might be possible if you have very powerful thrusters, functionally unlimited RCS fuel, and G forces don't matter...

like that station that is in orbit around a pulsar star and destroys anything trying to take off from it ?

Only if it is only spinning along one axis. Very likely to be spinning on multiple axis. That said, with enough money and effort I'm sure we could figure something out, like shooting it strategically with small projectiles to slow the spin, etc.

Anything "spinning among multiple axes" is just spinning around a single compound axis? There's no reason for a spacecraft to limit itself to any earthbound reference frame when it comes to matching frame with an incoming body from outer space.

In three dimensions, the rotation around one axis can affect the distribution of mass around other axes of rotation. That change in the moment of intertia causes acceleration, which can result in chaotic motion even without the addition of any outside forces.

Reminds me of the tumbling T-handle. A small tool is spun up in one axis, and due to some interesting physics, ends up flipping over on another axis every few seconds.

https://rotations.berkeley.edu/a-tumbling-t-handle-in-space/


I wonder if it's reproducible in vacuum or the air is necessary to destabilize it?

It's about angular momentum and happens whenever the axis of rotation differs - even slightly - from the semi-major axis. Interaction with a fluid is not necessary.

You can demonstrate it at home with your smartphone (or, more canonically, a tennis racket), and see for yourself that the tumbling happens much too quickly to be explained by whatever force the air is imparting.


What do you mean by "other axes of rotation"? As long as the object is rigid and not acted upon by external forces, its axis should never change, since both the direction and magnitude of angular momentum are conserved.

Wikipedia talks of "chaotic rotation" of astronomical objects, but only over long timescales due to gravitational interactions and thermal effects. On short timescales, its axis shouldn't change much at all, unless you bump into it and apply an off-axis torque.


Look at the Dzhanibekov effect

https://www.youtube.com/watch?v=8DOY21HnJII


Alright, that makes more sense, the trick is that the (conserved) angular momentum vector need not be parallel with the angular velocity vector, the simplest example being torque-free precession [0]. It doesn't help that most examples of non-constant angular velocity have external forces in the mix to confuse the reader.

[0] https://en.wikipedia.org/wiki/Precession#Torque-free_or_torq...


Unless acted on by an external force, all rigid objects only rotate about a single axis, do they not? That axis just might not be aligned with any useful parts you'd want to grab on to.

You might enjoy this, if you haven’t seen it: https://www.youtube.com/watch?v=1n-HMSCDYtM

Does it really work this way? If the craft is rotating along any other axis than its direction of travel, wouldn't the matching craft have to be revolving around it, not just rotating?

That sounds absolutely terrifying for the astronaut. Imagine the whole universe spinning past you every second. Not to mention the forces.

Perhaps scientists would have some particular interest in that particular hardware as it had been launched and flown in Earth orbit, but I'll tell ya: it's way easier to get your hands on flight spare equipment; while this stuff hasn't flown, it's probably a really good copy of whatever they did launch into space, and way better condition.

When I worked "on Mars" there was a "flight spare" copy of a Viking instrument which was the predecessor to the one we were working on, and of course it was encased in Plexiglas as a museum piece, but it was truly a redundant copy, as NASA was into copying everything they sent into space, (what was the saying in Contact? "Why have only one, when you can buy two at twice the price?") so that if anything needed to be tweaked, or went wrong, they would have this copy on the ground that they could experiment with to their hearts' content.


I don't think we have any active craft capable of recovering it. The space shuttle probably could have done it, but with a cost of about $1.5b per launch, there is no way that would be worth it.

SpaceX's Dragon 2 easily has enough cargo capacity to bring it down (~3 tons vs 0.5 ton), but there's still the question of intercepting, capturing, and securing it in Dragon's cargo bay. That would still cost something north of $100m to recover the lander.


Dragon likely wouldn't be able to get it, unfortunately.

The lander would easily fit into the unpressurized cargo bay (the "trunk"), that is typically used to launch various vacuum-bound payloads alongside pressurized cargo inside the capsule. However, for a return from orbit, the trunk cannot be used - it is not protected by a heat shield, and is ejected before re-entry.

You are correct that the return payload mass of a Dragon would technically allow it. But you'd need to somehow get the captured object _inside_ the capsule, which may be possible via the EVA front hatch for something smaller, but not 1m in diameter like the Venera lander.

Starship should be able to do it, since it is fully protected by heat shielding and returns in one piece, not ejecting any modules in orbit. But that's quite a while from being operational yet.


No, the Space Shuttle could not have done it. It had nowhere near the ΔV that would have been necessary for an intercept and capture. The OMS had only a tiny fuel supply. We're talking about orders of magnitude difference here.

Should have been possible with a dedicated launch. This thing's current orbit is on the same* inclination as the ISS, and at lower altitude.

*(They're both at exactly the minimum inclination, 51°, achievable by a Soviet launch from Baikonur).


Intercept and capture was one of the functional purposes of the shuttle. It was intended to refuel KH-12 recce sats.

Only for a very limited set of orbital parameters.

Most of the benefit of the Shuttle program, and manned spaceflight in general, has come from R and D on the launch process, or from the prestige and bragging rights of being able to launch humans into space. So once they're up there, you're getting your money's worth (or not) no matter what they do, you may as well do something cool like recover a historic satellite.

The Shuttle program was a disaster that consumed NASA's budget and set back manned space flight by a generation.

You're quite overestimating our capabilities as a species if you think that planning, developing, and launching a recovery mission in a few weeks would be even remotely feasible. Sure, we've known that the thing's up there all this time, so in the very counterfactual scenario where we had started thinking about a retrieval mission a few of years ago, and the Space Shuttle was still a thing, and someone was willing to foot the n-hundred-million-dollar bill, I guess? I don't think any nation on Earth currently has the hardware required to rendezvous with a random spacecraft in orbit and bring it down in one piece. The Shuttle was unique in that respect.

Feasible for a 50yo project motivated by nostalgia? No

National existential crisis? They'd probably take Dragon and figure out how to make it work.


In principle this is not science fiction, Space Shuttle captured a satellite, https://en.wikipedia.org/wiki/STS-49, they just didn't return it back. It was a catch, fix, and release.

https://en.wikipedia.org/wiki/STS-51-A brought two satellites back in the cargo bay that had not reached their proper orbit on a prior launch.

https://en.wikipedia.org/wiki/STS-32 brought back the Long Duration Exposure Facility experiment, a bigass science probe the size of a small school bus.

There are still missions that are classified that could have done so as well.

It was something the shuttle was designed to do, with the 60-foot cargo bay requirement and the ability to bring back the mass it flew with coming specifically from the military.


I've heard that one of the things they wanted the shuttle to do was launch, capture a spacecraft in polar orbit, and land at the launch site within a single orbit. Some say it was so they could secretly grab a Soviet satellite right out of the sky when it was out of range of Russia, but I'm not sure how you would secure something like that in the payload bay.

That's an urban legend. There were never any plans to capture a satellite in a single orbit. It was supposed to be capable of making an emergency landing after one orbit, but not while releasing or capturing a satellite. The 1950s Air Force X-20 Dyna-Soar was intended to launch a recon satellite and land in one orbit, but not recover a foreign satellite in one orbit.

> I'm not sure how you would secure something like that in the payload bay.

Tighten down some ratchet straps, wiggle it a bit and say, 'that'll hold it'


> STS-51-A marked the first time a shuttle deployed two communications satellites, and retrieved from orbit two other communications satellites

That's very interesting. First time I heard about it. Thanks for the reference!


Is Catch Fix Release like Trap Neuter Return? Did they snip its ear tip for identification?

https://en.wikipedia.org/wiki/Trap%E2%80%93neuter%E2%80%93re...


> Is Catch Fix Release like Trap Neuter Return?

And Soviets were wondering why their satellite numbers were not growing...


They did that when they fixed the Hubble telescope too. Five times.

https://en.m.wikipedia.org/wiki/Hubble_Space_Telescope#Servi...


How many satellites have the USAF and US Space Command captured ? Inquring minds want to know.

They do run their own unmanned shuttle based platform spacecraft but full capabilities aren’t public.

The space shuttle also captured and returned the long duration exposure facility satellite, a materials test bus for future missions. Extremely uneconomical, however.

This thing would be going at higher than earth orbital velocity, making an in-space capture of it more or less impossible.

Who’s gonna pay for that?



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