"MAHEM" (Magneto Hydrodynamic Explosive Munition - stream of molten metal at incredible speed -
Directed-energy weapons DEW utilize lasers, high-powered microwaves, and particle beams. Projects in development by the US have names like Airborne Laser, the Active Denial System, and the Tactical High Energy Laser
"parasitic microsatellite - designed to attach itself to other satellites to destroy or damage them
ICBM - in the 1950's the US Air Force planned to detonate a nuclear bomb on the moon. At the time, an intercontinental ballistic missile (ICBM) carrying a nuclear warhead possessed the capability to reach the moon
EMP/HEMP - High-altitude weapons using electromagnetic energy may destroy and disrupt electronic and electrical devices, causing a burst of electromagnetic radiation (electromagnetic pulse, or EMP) to produce current and voltage surges.
Manipulating an orbiting asteroid - Could an orbiting asteroid be manipulated to smash down on an enemy target on Earth? It's possible, but doesn't seem like an efficient way of doing battle