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55 votes
Accepted

Has any space agency saved Earth from a major calamity any time?

More fundamental, and a question if it counts as a 'space agency' act being NOAA led but weather satellites not only reduced the fatalities associated with weather data collection but increased the ...
GremlinWranger's user avatar
53 votes

Does NASA have an end-of-the-world policy?

First off, large life-ending asteroid impacts are very rare as there aren't many of them out there and we've found almost all of them: Looking at the 'continent' and 'global catastrophe' areas of ...
astrosnapper's user avatar
  • 2,506
45 votes

Has any space agency saved Earth from a major calamity any time?

Ozone depletion was hypothesized and first measured without the means of satellites according to the wikipedia article. However, satellite data was apparently very helpful in showing the scope/size ...
TAR86's user avatar
  • 489
40 votes

Has any space agency saved Earth from a major calamity any time?

Has any space agency saved Earth from a major calamity at anytime? There are historians who believe that the US–Soviet and US–Russian collaboration, for example in the Apollo–Soyuz Test Project, the ...
Jörg W Mittag's user avatar
27 votes

If an extinction-level asteroid were to be detected, could we avert it?

Yes. (But it requires a bit of dishonesty.) Simply because an "extinction level" asteroid does sufficiently limit the possible nature of the object. To be extinction-level, it would need to ...
CuteKItty_pleaseStopBArking's user avatar
17 votes

Has any space agency saved Earth from a major calamity any time?

As yet, no space agency has blasted anything that may have posed a hazard to Earth. One of the issues with blasting such hazards is the numerous fragments of the blasted object may pose a greater risk ...
Fred's user avatar
  • 13.1k
17 votes

Has any space agency saved Earth from a major calamity any time?

Like diverting meteor path away from Earth or blasting giant asteroid which was expected to impact Earth etc. Not yet. However, later this year (between 26 September 2022 and 2 October 2022), NASA's ...
Jörg W Mittag's user avatar
13 votes
Accepted

How will the closure of the Arecibo dish impact deep space communications?

There is some indirect evidence that Arecibo's loss has already impacted communication with some of the deep space probes. NASA's official statement on Arecibo says this: NASA’s Goldstone Observatory ...
DrSheldon's user avatar
  • 48k
9 votes

Asteroid Defense

Well SpaceX doesn't plan it's missions (except for current Mars ambitions and the planned Starlink satellite constellation). SpaceX is the company that others hire to carryout their space objectives. ...
Rickest Rick's user avatar
  • 1,669
7 votes

If an extinction-level asteroid were to be detected, could we avert it?

Perhaps. Perhaps not. There are programs to look for these asteroids. Sometimes they work. Sometimes not. You assumed in your question that it would be detected. Just how much warning time is there? ...
o.m.'s user avatar
  • 171
6 votes

Does NASA have an end-of-the-world policy?

Yes! Or more precisely, they're developing plans to detect and prevent it. NASA's Planetary Defense Coordination Office (PDCO) exists to... coordinate planetary defense. This includes: Planning ...
Schwern's user avatar
  • 8,016
6 votes

Why is comet deflection so hard (and how does a fusion rocket help)?

Assuming that our vaporization is at least as effective as a rocket engine (ISP 500) that gives 2.5m/s delta v Unlikely - the rocket engine uses a shaped engine bell tuned to give the best thrust (...
Andy's user avatar
  • 5,178
5 votes

Why are DART's solar panels aligned like this?

DART uses the Roll-Out Solar Arrays (ROSA) and is one of the first spacecraft to do so - certainly the first interplanetary one. ROSA has been demonstrated on the ISS and is going to become a primary ...
John McCarthy's user avatar
5 votes

How Much Could You Deflect the Path of a 500 meter Diameter Asteroid with 100 STAR48 Rocket Motors

Probably the first key point here, is that if an asteroid is detected 6 months out, it will be on it's final orbit, with geometry something like this So any attempt to intercept is not doing fuel ...
GremlinWranger's user avatar
5 votes

Scenarios for asteroids 2000 QW7 and 2010 CO1 hitting the Earth?

There are no scenarios for either of those asteroids hitting the earth on the next approach. Both have been tracked carefully for years, and the closest approach has been calculated at 0.035428 ...
GdD's user avatar
  • 20.3k
5 votes

Can objects be deorbited by a satellite using a magnetic field?

No, the range of a magnetic field is too short to be usable. Magnetic field strength is proportional to 1/r3, so a magnetic field is only effective at very short distances (less than 10 meters), and ...
Hobbes's user avatar
  • 128k
5 votes
Accepted

Can objects be deorbited by a satellite using a magnetic field?

A magnetic field is one way for one satellite to exert a force on another, changing the orbits of both. Since satellites are mostly made of aluminium, titanium and carbon fibre based composites, ...
Steve Linton's user avatar
  • 19.6k
4 votes
Accepted

How much asteroid can we divert from the Earth?

There's no simple answer here. In the simple case (no other encounters before impact) you need to generate no more (and maybe a lot less depending on where it's going to hit) than a bit over 6500 ...
Loren Pechtel's user avatar
4 votes

Asteroid Defense

Has SpaceX thought about landing on an asteroid, and deploying technology that can either redirect or disassemble an incoming asteroid to avoid or lesson the asteroids impact on earth? Except perhaps ...
David Hammen's user avatar
  • 74.9k
4 votes

Why is comet deflection so hard (and how does a fusion rocket help)?

I don't have an exact answer but some relevant bits of information: You're looking at how much material is vaporized. That's irrelevant, vaporizing material gets you nothing. To move the comet you ...
Loren Pechtel's user avatar
4 votes

Why is comet deflection so hard (and how does a fusion rocket help)?

The simple fact is that we don't know what the effects of a nuclear blast on a comet would be as it's never been done, and each comet is different. You're thinking of a nuclear explosion next to a ...
GdD's user avatar
  • 20.3k
3 votes

If an extinction-level asteroid were to be detected, could we avert it?

It would depend massively on the size of the asteroid, it's composition and how far out it was detected. For the true planet killers it is extremely likely that the asteroid would be detected years in ...
Pioneer_11's user avatar
3 votes

How big an asteroid could we take out with an ICBM?

Leaving aside the practicalities of modifying an ICBM for intercept this is tricky to estimate since the ideal situation involves reducing the object to chunks under 20 meters or so evenly, and ...
GremlinWranger's user avatar
3 votes

What is "Planetary Defense", and what are the threats one can potentially defend against?

What are all the activities related to defending planets against impacts from things like asteroids or comets? Are they only things like "identification", "tracking", and "...
David Hammen's user avatar
  • 74.9k
2 votes

Why is comet deflection so hard (and how does a fusion rocket help)?

Another way of estimating the energy transferred to the target? 10E+13 kg of comet v.s. 500 kT Nuke: where 1kg TNT=4.2 MJoule. This looks like a 20 km (13 miles) diameter comet. Looks like 10 times ...
Per Ohlin's user avatar
1 vote
Accepted

Puzzler: Why higher solar phase angle (SPA) allows for many more feasible FastKD (kinetic deflection) communications satellite “hijacking” missions?

I don't understand the orbital mechanics aspects of this statement: higher allowed Solar Phase Angle (SPA) at impact is required to achieve high deflection performance But, interpreting: SPA ...
BrendanLuke15's user avatar
1 vote

How will the closure of the Arecibo dish impact deep space communications?

It is too late now to think about a repair. The instrument platform crashed into the dish at the first day of December.
Uwe's user avatar
  • 49k
1 vote

Does NASA have an end-of-the-world policy?

There most definitely is a protocol in place for the verification process and disclosure. Most large institutions have protocols in place for front-line research, data, verification, information, ...
inter's user avatar
  • 11
1 vote

Does NASA have an end-of-the-world policy?

The other answers address non-doomsday situations. The worst case scenario I can think of is a large comet from the Oort cloud. Comet Hale-Bopp, for instance, was 40-80 km across. That's much larger ...
Mark Foskey's user avatar

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