bobbymike said:
sferrin said:
shockonlip said:
Rocket sleds are also currently the fastest land based vehicles.
Record currently held by a Holloman sled at 9000 + ft/sec (Mach 8.5).
There's footage of that run on youtube. (I'd love to know the details of the "Roadrunner" motors they used to power two of the stages.)
The chemical makeup of the energetic material would be interesting. 9000 ft/sec is 60% of the speed of detcord (pure explosives) so the propellant must be, I'm speculating, a very high percentage of HMX/RDX or CL20 (or other HEDM).
Interestingly 9000ft/sec coverts to about 2.75km/sec and MDA is talking about 3.5km/sec boost phase air and ship based interceptors. That would be close to 11,550ft/sec.
We are obviously talking cutting edge propulsion systems.
If you can stand all the pop-ups globalsecurity finally updated some of the missile defense info on their site (you only get 8-page views a month now unless you want to pay for it though). The one to look at is here:
http://www.globalsecurity.org/space/systems/hedi.htm
Over on the right there are several links to endoatmospheric programs that were follow-ons to HEDI. I've not seen much on any of them beyond what's on those pages (and since I'm not willing to pay 8$/month for a spam assault I won't see them again until next month). I've seen other hints at things they've played around with but not much in the way of details. There's a brief write-up of HiBEX in which they refer to the use of external burning (achieving 800-1000isp IIRC) for manuevering terminal-phase ABMs in the atmosphere in a seperate program. (Come to think of it they mentioned external burning in another application in that book "Lightning Bolts".) They also looked at the possiblity of running down manuevering ICBM RVs in the atmosphere.
Back to the Roadrunner motor. I may have posted this elsewhere on this site but what I do have is this:
"The Super Roadrunner motor developed specifically for the Hypersonic Upgrade Program produced 228,000 pounds of thrust for 1.4 seconds and weighed only 1,100 pounds. The maximum acceleration of the sled was 157-g’s, or 157 times the force exerted by gravity. When the payload impacted the target, it had 363 mega joules of energy – that’s equal to a car impacting a brick wall at 2,020 miles per hour."
If we just pick an arbitrary 100lbs for the case weight that's an ISP of 319 for a solid motor. It may be that it can be that "hot" though because it doesn't have sensitivity requirements.
