China Plans Deep Impact Mission

Comatose51 writes "China is planning its own Deep Impact mission. The goal of the mission, unlike the exploratory NASA project, is to push potential life-ending comets or asteroids away from a collision course with the earth." From the article: " The third nation to launch a man into space has lofty space ambitions that include putting two astronauts into orbit this September and eventually sending up a space station and even a manned mission to the moon."

Star Wars speace-weapons research

[Anonymous Coward]

Maybe these tests are really just a way nations can slightly tip their hands regarding their black-project space-weaponry research, without directly acknowledging such undercover programs.

The math doesn't look good...

[G4from128k]

An estimate of the orbital delta-v for Tempel /Deep Impact [universetoday.com] suggests a velocity change of only 1 cm/hour (I can't vouch for the math). Assuming we would need to nudge a threatening body by 1/2 the diameter of the Earth (from direct hit to grazing pass-by), we would need to know to hit a Tempel 1-sized body in advance by over 73,000 years. This type of mission would work 10 years in advance for much smaller bodies (say less than 350 m in diameter). Even these estimates assume a perfect strike by the deflecting deep impactor -- a margin of error or the need to push the object several Earth-diameters further reduces the potential for this method.

Kinetic energy is not the way to go. Deep Impact delivered only about 4.5 kt of TNT. In contrast, a good sized thermonuclear weapon could deliver thousands of times that energy (even taking into account the relatively poor conversion of 100 megatons yield into delta-V).

Of course...

[dbolger]

the real irony comes when their first test to see if they can "nudge" a comet accidentally sends the target spiralling towards Earth ;)

Re:The math doesn't look good...

[iggymanz]

Here's neat link mentioning megatons of yield needed to deflect 1km asteroid by cm/s. here [spaceref.com] Repeated applications of the more usual 1-5 MT warheads seems more reasonable than the need to invent a 100MT monster. But if the dimensions of the asteroid are of the order of dozens of cubic km then we're probably screwed! 8D

Just to wax philosophical for a moment, I hear people talk about founding space stations so we "don't have all our eggs in one basket", but if the entire earth gets wiped out does it really matter if we have a couple dozen people in a space station or moon base? nah, who gives a crap at that point, certainly you or I won't....

Re:World killer?

[Sancho]

I guess some people don't know the definition of the word Troll....

See, it'd be trolling if I suggested that Bush's war with Iraq was merely a distraction to keep the public from knowing about the comet.

Actually

[Alien54]

Actually, the sneaky thing would be to aim a tiny comet or fragment thereof in such a way as to take out "accidently" an appropriate city of their political enemy. It would work as part of their secret warfare strategy.

Re:Chinese technology

[Anonymous Coward]

There is still room for improvement for the Chinese spacecraft [wikipedia.org]designs.

Re:Which method?

[davmoo]

It comes from back in the day when the space station was originally proposed. It was a much larger and more useful design, and it was going to be named "Freedom". But as usual, our government was more interested in weapons and such than science, so the design was scaled back *massively* after funding cut after funding cut. This started a popular joke going around that because of the reduction in size of the proposed station, there was no longer room to paint the word "Freedom", so they had to also cut the name down to "Fred".

"Freedom" instead became the current almost pointless International Space Station (ISS).

Re:Which method?

[davmoo]

Mercury and Gemini I'd agree with you without exception.

Apollo delivered its goals, but was scaled back. There were supposed to have been at least two more flights in the program, and it could have achieved far more than it did.

Skylab worked, but I don't think it was in the general plans for it to fall out of orbit after only three missions.

Apollo/Soyuz, yeah, I'd have to agree on that one too.

The shuttle works, but it has never fully lived up to expectations. Way over budget and late. Original plans called for it to regularly make 10 flights per year or more. Its never come close. Likewise, while its cheaper to operate than one time use rockets like a Saturn, it has never come close to original projections. And finally, this is what was supposed to keep Skylab from falling down.

ISS was massively scaled down from original plans (reference "Fred" in my first post). Something is regularly breaking down, we're dependant on another country to keep it supplied and get us there and back, its on a scaled-back crew roster now, and NASA regularly talks about the possible need to mothball it for extended periods of time. Successful, probably. But I think "resounding" is stretching it.

One final thing on ISS. And I tried to find specific times for this, but since Mir was de-orbited its apparently hard to come by accurate information. But from the time of placement of the first and main module of Mir in to orbit until the station was dropped was 15 years. The first and main module of ISS has only been in orbit slightly over 6 years (according to NASA information I just looked at). ISS has been manned for a period of 4 years plus some. I cannot find information right at the moment on the length of time that Mir was manned, but considering at least one mission was longer than a year, I have a hard time believing that ISS has been manned longer than Mir. Can you point me to a site that can confirm that?