3 ms·

would a MARV-tipped ICBM be able to reach a target faster than flying straight at it at Mach 5? I was looking for MARV reentry velocities, couldn't find any nu

would a MARV-tipped ICBM be able to reach a target faster than flying straight at it at Mach 5? I was looking for MARV reentry velocities, couldn't find any numbers. A regular ballistic missile hits mach 20+ on reentry but I don't know if it maintains that speed all the way to the target.

hindsightbias 5y ago
Marvs are just Mirvs that maneuver. They will go the same speed until they maneuver.
SonicScrub 5y ago
From my understanding, the primary benefit of the Hypersonic Missile over the ICBM is not the speed of payload delivery, but the amount of warning given to the target. An ICBM needs to ascend 100s of kms, thus enabling it to be detected by very far away radar systems. Those same radar systems that would be over the horizon at the lower altitudes within the atmosphere. Launching an ICBM almost immediately announces to the world "I am launching a nuclear warhead", thus enabling countermeasures to be readied, and a retaliatory strike to be launched. The time between this warning and the strike is indeed small (measured in 10s of minutes), but that's much more time than a hypersonic missile gives.
- nautilius 5y ago
  And the maneuverability - if you just adjust the course slightly ten seconds before impact, at these speeds, that’s a big difference. Ballistic mostly just falls down, i.e. you know what it will hit when you observe the launch (somewhat simplified).
  - fnord77 5y ago
    Missiles since the 80s or so don't just fall down. The discontinued Pershing MARV could perform 25G maneuvers/corrections and was radar guided and had terrain mapping.
    - nautilius 5y ago
      Well yeah, hence "(somewhat simplified)". One is a lifting body that control its flight path and can decide whether to strike or to just keep flying for another 1000 miles, the other can slightly adjust its falling down path and wobble enough to hopefully confuse countermeasures.
kubanczyk 5y ago
> A regular ballistic missile hits mach 20+ on reentry but I don't know if it maintains that speed all the way to the target. The word "ballistic" means it doesn't maintain the speed. Etymologically and practically it's about throwing a stone, i.e. finding out what happens when you give it an initial velocity with approximately zero delta-V budget for the main part of the flight. But everything gets complicated with time, so there are now depressed trajectories (i.e. not-entirely-ballistic flight paths) for the ballistic missiles. But these still do not carry dramatic delta-V.

hindsightbias 5y ago

Marvs are just Mirvs that maneuver. They will go the same speed until they maneuver.

SonicScrub 5y ago

From my understanding, the primary benefit of the Hypersonic Missile over the ICBM is not the speed of payload delivery, but the amount of warning given to the target. An ICBM needs to ascend 100s of kms, thus enabling it to be detected by very far away radar systems. Those same radar systems that would be over the horizon at the lower altitudes within the atmosphere. Launching an ICBM almost immediately announces to the world "I am launching a nuclear warhead", thus enabling countermeasures to be readied, and a retaliatory strike to be launched. The time between this warning and the strike is indeed small (measured in 10s of minutes), but that's much more time than a hypersonic missile gives.

nautilius 5y ago
And the maneuverability - if you just adjust the course slightly ten seconds before impact, at these speeds, that’s a big difference. Ballistic mostly just falls down, i.e. you know what it will hit when you observe the launch (somewhat simplified).
- fnord77 5y ago
  Missiles since the 80s or so don't just fall down. The discontinued Pershing MARV could perform 25G maneuvers/corrections and was radar guided and had terrain mapping.
  - nautilius 5y ago
    Well yeah, hence "(somewhat simplified)". One is a lifting body that control its flight path and can decide whether to strike or to just keep flying for another 1000 miles, the other can slightly adjust its falling down path and wobble enough to hopefully confuse countermeasures.

kubanczyk 5y ago

> A regular ballistic missile hits mach 20+ on reentry but I don't know if it maintains that speed all the way to the target. The word "ballistic" means it doesn't maintain the speed. Etymologically and practically it's about throwing a stone, i.e. finding out what happens when you give it an initial velocity with approximately zero delta-V budget for the main part of the flight. But everything gets complicated with time, so there are now depressed trajectories (i.e. not-entirely-ballistic flight paths) for the ballistic missiles. But these still do not carry dramatic delta-V.