You, me and debris: NASA cans ISS spacewalk because it's getting too risky outside
- Reference: 1638275096
- News link: https://www.theregister.co.uk/2021/11/30/iss_debris/
- Source link:
The spacewalk by NASA astronauts Thomas Marshburn and Kayla Barron was due to have started today with a switch to spacesuit battery power at 12:10 UTC followed by an exit from the outpost's Quest airlock.
The planned 6.5-hour spacewalk was to have Marshburn positioned at the end of the Canadarm2 robotic arm and swung out over the structure by ESA astronaut Matthias Maurer at the controls within the orbiting lab. Barron was to assist with the replacement of an antenna on the P1 truss.
[2]
The antenna recently lost the ability to send signals to Earth via NASA's Tracking and Data Relay Satellite systems. Not the end of the world, as the ISS is rammed full of redundancy, including in the comms department, but since a spare is available (on the truss structure) managers figured restoring full redundancy was worth a jaunt outside the airlock.
[3]Russia's orbital insanity is almost beyond redemption – but there's space for improvement
[4]Russia blows up old satellite, NASA boss 'outraged' as ISS crew shelters from debris
[5]International Space Station fires rockets to dodge chunk of destroyed Chinese satellite
[6]Now that's a splash down: Astronauts spend 8-hour trip to Earth in diapers after SpaceX capsule toilet breaks
Unless, of course, there is a debris notification.
The problem is the short notice of the impending debris event. The notification was only received on the evening of 29 November, less than 24 hours before Marshburn and Barron were due to venture outside, and managers sensibly opted to postpone activities until NASA was able to properly assess the risk to the spacewalkers.
[7]
NASA did not immediately respond to a question from The Register concerning the source of the debris, but the space above Earth has become increasingly crowded of late. A few short weeks ago, Russia's military demonstrated its might (but not much sense) with the [8]destruction of one of its own satellites by an anti-satellite missile .
The resulting cloud of debris sent the ISS crew scurrying for shelter while spaceflight bosses expressed their outrage from the safety of the ground. We imagine that there were some interesting chats aboard the ISS over dinner. ®
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[1] https://www.nasa.gov/press-release/nasa-to-air-spacewalk-to-swap-communications-antenna-on-space-station
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YaZYvANi5@J4IaZ74taPLgAAANU&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://www.theregister.com/2021/11/22/russias_orbital_insanity/
[4] https://www.theregister.com/2021/11/16/russia_satellite_iss/
[5] https://www.theregister.com/2021/11/11/iss_debris_burn/
[6] https://www.theregister.com/2021/11/09/broken_toilet_spacex/
[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YaZYvANi5@J4IaZ74taPLgAAANU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[8] https://www.theregister.com/2021/11/16/russia_satellite_iss/
[9] https://whitepapers.theregister.com/
Damage protection from space debris
How much additional protection, and thus extra fuel, does a rocket have to carry because of debris?
Re: Damage protection from space debris
Rockets ? They don't have protection. The chances during the minimal amount of time they are up isn't worth it.
Re: Damage protection from space debris
Debris in orbit is a real issue because of the energy involved in a collision
ke=0.5mv^2
When v is in the order of 10's of km/s it hardly matters what m is, contact is going to hurt - be it full on or just a glancing blow. Trying to defend a spacecraft from that impact is hard for anything over paint fleck size, it's easier to get out of the way.
I won't try to give examples as I am proven to be incompetent when using calc, so actual figures are left to the reader as an exercise!
Re: Damage protection from space debris
A 1g piece of debris (a really tiny nut for example), at low earth orbital speed of 17,500mph (about 8000m/s) has a kinetic energy of about 30KJ. That's equivalent to about 8grams of TNT. And yes, when things collide at orbital speeds, they explode.
An old fashioned WW2 hand grenade had about 50g of TNT equivalent, so an orbital collision with a 1g object is about 1/6 of a hand grenade going off.
Of course, colliding with a slightly larger object, only 6grams (a bit less than a still small M8 nut) is about the same as a hand grenade going off, that's practically impossible to armour a satellite against. Just out of interest, I've weighed a simple biro I had on my desk: 7grams. So a dropped biro in orbit is like a hand grenade when it hits!
That orbital velocity of about 8000 m/s is the one way speed. If two objects collided head on, that's a doubling of the closing velocity, or 4 times the kinetic energy. So a dropped biro colliding head on is like 4 hand grenades going off!
Re: Damage protection from space debris
The pen is mightier than the sword hand grende
Re: Damage protection from space debris
Aren't all such collisions head-on ? Head-to-tail would imply both objects orbiting in the same direction at the same speed, and hence with very little kinetic energy able to be liberated.
Re: Damage protection from space debris
Kind of, but not quite.
Two objects can have a nearly-parallel but intersecting orbit, both going in almost the same direction at orbital speed. The impact is still "head on", in that there is no other frame of reference, but the collision velocity is only a fraction of the two orbital velocities combined.
As an analogy, imagine driving along the motorway next to another car. You're both going exactly 70mph. Imagine the other car drifts slightly in his rather narrow lane and hits the side of your car. You're both going 70mph each, but only probably contacting each other at something less than 1mph. You'd probably both keep going just fine (until you pulled over to have an argument)
Re: Damage protection from space debris
None: the speed of debris is so high that any armor you could plausibly carry would be useless, and any armor that could plausibly help is far too heavy. So you don't use any, you dodge the bits you can track, and you pray hard that the bits you can't track don't hit anything really important.
In space
No-one can hear you sc
This is getting more and more like "Gravity" every day.
I really feel for these poor folks, they must feel like they are on a terrible reality TV show.
With Covid, space debris and solar flares plus the risk of the station disintegrating around them because
someone forgot to insert a - in the control algorithm, and the risk of the country they came from effectively
taking pot shots at them because they wanted to prove they have bigger cojones than the other country..
Is it no wonder that stress is *1 on their list of ailments?
I heard that someone on Mir needed extensive rehabilitation when he finally came back to Earth after over
a year in space, compounded by several high profile rocket failures.
The antenna recently lost the ability to send signals to Earth
I guess it took over 72 hours to schedule replacing the AE-35 unit!
Priorities
So, rather than wasting resources on fanciful Moon and planetary escapades our actual real and present priority is to: "CLEAN YOUR MIDDEN OF A ROOM!!!" i.e. tidy up low Earth orbit, so that we can get on with all the exciting exploration stuff undistracted by our filthy laziness.
Designing cost-effective orbital rubbish collectors would be a very worthwhile exercise for further, and less rubbishy, adventures in spaaaaace!
Re: Priorities
There are already a lot of studies looking into this, but its not a particularly easy problem to sort out.
Mainly because the things you are trying to catch are travelling at massive velocities, so trying to catch them directly, will likely lead to effectively an explosion and more (but smaller) debris, which doesn't help the situation. People are experimenting with various aerogels and foams to try and mitigate this, but well at the velocities we're talking about, things still have a tendency to go boom.
If you try to sidle up to the debris, getting up to speed, entering it's orbit and then slowly closing the distance to it, before grabbing it, well that will work, but you need a lot of fuel, and you can only really do this with big things. So its not considered particularly effective. The recent Lockheed mission to refuel an existing satellite so it can keep operating, is effectively an example of this in practice, but one that actually might have a business case.
The future, probably has a few missions to sidle up and grab big junk (or refuel it to keep it going), but most of the current focus is on making sure anything we put up now, either comes back down quickly on its own (either through drag mechanisms or thrusters), or for the bigger ones that they go out to a graveyard orbit. But unfortunately none of this particularly helps when a$$hats go and deliberately blow shite up, causing massive amounts of new debris. You almost hope that the debris wipes out something valuable of theirs, but unfortunately Karma is rarely that specific or sensible....
Re: Priorities
Way back around the time of Sputnik (which is still up there), no one considered that low orbit or really any oribit of earth would become crowded with junk. Instead of actively deorbiting things like boosters, dead satellites, etc. It's now become a real problem. Even the Musk satts are creating problems and not just for astronomers.
Space... a real mess. Maybe the final frontier will soon be blocked.
< interesting chats aboard the ISS over dinner.>
Fancy a postprandial peregrination?