PDA

View Full Version : Why aren't we using anti-matter instead of rocket fuel for space exploration?



MVAgusta1078RR
2014-Mar-25, 11:03 AM
I understand it's been created in the lab and it's the most efficient source of energy known to man kind. A. I know there hasn't been much made and B. It's unstable and dangerous but we should at least try it on all unmanned missions we launch into space like probes and satellites etc. Wouldn't it drive the cost down rather than using hundreds of gallons of fuel that's not even renewable anyways?

ShinAce
2014-Mar-25, 01:45 PM
It would drive the cost up. Antimatter is extremely expensive and nearly impossible to transport.

ravens_cry
2014-Mar-25, 02:07 PM
Even if you can create and store large quantities of antimatter, you still need some kind of propellent to chuck out the back of your space craft using that energy. A pure photon drive is so incredibly inefficient as to boggle the imagination.

Swift
2014-Mar-25, 02:15 PM
I understand it's been created in the lab and it's the most efficient source of energy known to man kind.
From the wikipedia article (http://en.wikipedia.org/wiki/Antimatter#Artificial_production) on antimatter:

On 26 April 2011, ALPHA announced that they had trapped 309 antihydrogen atoms, some for as long as 1,000 seconds (about 17 minutes). This was longer than neutral antimatter had ever been trapped before.[35][36] ALPHA has used these trapped atoms to initiate research into the spectral properties of the antihydrogen.[37]

The biggest limiting factor in the large-scale production of antimatter is the availability of antiprotons. Recent data released by CERN states that, when fully operational, their facilities are capable of producing ten million antiprotons per minute.[38] Assuming a 100% conversion of antiprotons to antihydrogen, it would take 100 billion years to produce 1 gram or 1 mole of antihydrogen (approximately 6.021023 atoms of antihydrogen).


Even if we had a design for a drive, there doesn't exist enough antimatter to even do something with.

Noclevername
2014-Mar-25, 04:09 PM
Even if we had a design for a drive, there doesn't exist enough antimatter to even do something with.

We can always harvest antiprotons from bananas.

EDIT: D'oh, wait, those are positrons! :doh:

cjameshuff
2014-Mar-25, 04:25 PM
I understand it's been created in the lab and it's the most efficient source of energy known to man kind. A. I know there hasn't been much made and B. It's unstable and dangerous but we should at least try it on all unmanned missions we launch into space like probes and satellites etc. Wouldn't it drive the cost down rather than using hundreds of gallons of fuel that's not even renewable anyways?

Just how much do you think "hundreds of gallons" of fuel costs?

ravens_cry
2014-Mar-25, 04:31 PM
Indeed. This is like saying. "Hmm, iron is so expensive these days, let's use solid platinum instead." Actually, that's magnitudes less expensive than using antimatter instead of rocket fuel.

JustAFriend
2014-Mar-25, 07:16 PM
Especially when we've only created a few billionths or trillionths of a gram....

So far it's just a sci-fi fuel.

ravens_cry
2014-Mar-25, 07:32 PM
Especially when we've only created a few billionths or trillionths of a gram....

So far it's just a sci-fi fuel.

The closest I have seen to anything approaching reality is antimatter catalysed fusion pulse propulsion (http://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_pulse_propulsion), and even that requires amounts of antimatter far above our current capability to create and store.

Jens
2014-Mar-25, 10:37 PM
In addition, keeping antimatter stable requires a vacuum, which is heavy to make, and a strong magnetic field, which is also heavy, so at least for the amount of antimatter we can handle today, any possible thrust would be far outweighed by the weight of the equipment required to handle it.

Noclevername
2014-Mar-25, 10:51 PM
I've heard of hypothetical methods for storing charged antimatter in molecular structures like CNTs. I can't recall the details but it doesn't seem like anything that will develop soon.

ravens_cry
2014-Mar-25, 11:18 PM
I am not sure that'd work. See, you can store atoms in carbon cages (like noble gases in buckyballs) because the like charges of the electrons repel each other. But positrons and electrons will attract each other.
At least, that's my understanding.

publiusr
2014-Mar-30, 08:22 PM
I think the AIMstar is the only "near" term use for anti-matter
http://en.wikipedia.org/wiki/AIMStar
http://www.projectrho.com/public_html/rocket/enginelist.php#aim

If I had unlimited funds, lived in the year 2100 and wanted to develop an interstellar precursor, I would use DUMBO NTR instead of a Centaur:
http://www.projectrho.com/public_html/rocket/enginelist.php#ntrsoliddumbo

With this as the payload's drive
http://www.projectrho.com/public_html/rocket/enginelist.php#fissionfragment