Second Sun

"What do we do now man?! Russian's got us outnumbered, shit's fallin' from the sky. We're screwed man, we are totally--"

"Shut up! Get a grip Corporal. Our weapons still work, which means we can still kick some ass."

Second Sun is the thirteenth level of Call of Duty: Modern Warfare 2.

Walkthrough
You start out just seconds before you left off in Of Their Own Accord where Pvt. Ramirez's team has just been shot down and is now defending its position. As Russian forces approach you, a search light whites-out the screen, then you play briefly as Sat1, an unnamed astronaut on an EVA mission outside the International Space Station (ISS). Mission Control in Houston asks you to look toward the dark side of the Earth for a bogey (the SLBM that Captain Price launched). You observe the missile's path until it eventually detonates in the atmosphere above Washington D.C. The shockwave soon reaches the ISS and destroys both the station and you. The explosion causes an EMP (electromagnetic pulse) that blacks out all the East Coast (except Florida), but it also saves the lives of many U.S. Army Rangers back in Washington. Aerial vehicles start to fall from the sky as your team makes its way to a building for shelter. After everything goes quiet, an Army runner tells the team to get to location Whiskey Hotel. After plowing through some remaining Russian personnel in an office building, you get to the President's secret bunker under the East Wing.

Trivia

 * The scene at the beginning of this level is exactly the same as the end of level "'Of Their Own Accord." This is because it was the time after the events of "Contingency ."
 * In the briefing part of the level, Shepherd is talking to the Secretary of Defense about the incoming ICBM possibly destroying Washington D.C., stating that "we've rebuilt it before, we can rebuild it again." This is a reference to the War of 1812 between the U.S. and Great Britain, in which the British burned down the White House. Since then, however, the United States and Britain have never fought against each other in a war. As a matter of fact, in all the later wars with both the United States and the UK directly involved in, they are allies.
 * The part where you control Sat1 was supposed to be in a separate level/interactive cutscene called "International Space Station", similar to The Coup and Aftermath. It was merged with this level in the final version of the game.
 * After the EMP goes off your Holographic sight is immediately disabled (it contains an integrated circut and is unshielded) while the helicopter and lights are still active. Also, the lights in the White House are still operational, yet the EMP shuts off power to nearly the entire East Coast (This alludes that the White House and everything within is shielded against EMP attacks).
 * While the concept of a low-orbit nuke detonating and causing a wide-spread EMP is feasible, no shockwave would ever reach the ISS because, at perigee (closest approach to earth) it is at 341 km altitude. The station would eventually be damaged by the electromagnetic pulse, and the heat from the nuke can damage the ISS, or even ignite the oxygen on board.
 * This is the only level, besides No Russian, that contains no intel.
 * As in Exodus and "Wolverines!" it is implied that during the five years in between Call of Duty 4, and Modern Warfare 2 there was a Second Cold War.
 * This is the only level where you control two characters within the same level.
 * When you get to the President's bunker under the Eisenhower building Cpl. Dunn says he thought it was under the West Wing, but Sgt. Foley says that one's "for tourists" and this one must be the real thing. In a real map, the Eisenhower Building is actually west of the White House. When you start the next level, Whiskey Hotel, you somehow start east of the White House when in this level you ended west.
 * When Foley throws you a magazine for your gun while you are trapped in the helicopter, the previous magazine given to you by Pvt. Wade disappears mysteriously. This most likely happens because Ramirez is supposed to use all of the magazine.
 * The EMP apparently did not knock out power in southern Georgia or Florida because you can see the lights when you are Sat1.
 * Ramirez sustained severe injuries to both hands, yet this doesn't affect his aim or use of weapons in the slightest. The gashes can be seen throughout this level when reloading or switching weapons. However, in the next level, Whiskey Hotel, it seems that they have been treated and/or he has been issued a new pair of gloves.
 * The player cannot remain outside, despite avoiding the helicopters. If they look up, they will see a never-ending stream of helicopters falling from the sky (from altitudes no normal helicopter would fly at). One of these, a Little Bird, will actually "track" the player and will always crash close enough to kill them, regardless of where they are on the street.
 * The in-game appearance of ISS is modeled after the configuration the station from 2002-2005. The current configuration (as of November 2009) is different, in that the Station is slightly larger, with the second node and the European and Japanese labs installed and the P6 Solar Arrays have been relocated from the top of the Z1 truss as seen in-game to the port side of ISS, with another set of solar arrays on the starboard side. The 2009 configuration is actually close to how the station will look when completed in 2011.
 * The astronaut in the ISS scene appears to be grappled to some sort of a satellite. Such a spacewalk would be impossible to conduct from ISS, as all spacewalks conducted on ISS are tethered, where the astronaut is connected physically to the station, and it would be impractical to investigate a satellite from the ISS.
 * The crew of ISS as seen in game appear to be American. As ISS is an international venture, there are typically astronauts from all nations on board, and every ISS crew to date has included at least one Russian astronaut (or "cosmonaut"). It's possible with the political situation in Russia, space flights to ISS were suspended, although two Russian Soyuz spacecraft can be seen docked to the station. However, the spacecraft being docked is entirely plausible as the Soyuz are launched on a six-month basis (thus would have been launched just prior to the unrest) and remain up there until just before the next craft is launched for use as "escape pods" in case of an emergency.
 * At one part in the level you kill three men trying to open what looks like a fried BTR-80, After you kill the men Cpl. Dunn says, "What about the men inside?" Sgt. Foley responds, "What about 'em?" If you listen closely you can hear Russian soldiers banging on the walls and saying something in Russian. They only say this once when triggered and they do not speak again after. Dunn's remark about the Russians in the BTR could be a nod to earlier Call of Duty installments. In earlier titles, allied characters would always finish off a stricken vehicle by throwing a grenade down the hatch. However another possible alternative reason is that because the BTR's doors open electronically (bad design for emergency escapes) the Russians inside are trapped in a steel coffin, and will probably suffocate slowly.
 * Also, if the player fires at the BTR prematurely, the Russian soldiers both inside and outside the vehicle will not notice.
 * Whether or not this goes throughout the entire game, when you are given the M4A1 at the beginning of the level, you can see for a brief moment that it has retained its iron-sights even though it is attached to a Holographic sight. However as soon as you pick it up from the soldier giving it to you, it turns into what a M4A1 with Holographic sights should look like, meaning the iron sights disappear.
 * After leaving the building where you take shelter from the falling helicopters, if you look at the newspost, the headline for the newspapers reads "Call of Duty 2."
 * Dunn is the first to notice that optics are offline, saying "My Red Dot's down." However, if you look at his weapon, you'll see he is actually using a Thermal Scope.
 * Also Dunn's Thermal Scope appears to be still working.
 * When helicopters are falling from the sky, you have unlimited sprint. Interestingly, you don't have unlimited sprint when replaying the level on the PC version.
 * If you look carefully, the Ranger who gives you a weapon after the crash is different from the one who gave you the weapon in the mission Of Their Own Accord, this is because Pvt. Wade's appearance is random.
 * It is interesting to note that the only person using a Red Dot attachment is Ramirez (the player). However, Dunn and another Ranger have a conversation about their red dots not working even though their weapons have different attachments.
 * Swap the M4A1 holographic with a standard M4A1 with iron sights to make aiming easier and more accurate.
 * The Boeing that crashes outside of the building where you take cover makes strange noises as you approach it, likely because of the metal warping under such intense heat.
 * It is odd how the soldiers trying to get the soldiers out of the BTR don't even hear the gunfire happening in the office building less than 100 meters from their position. However, there was torrential rainfall in the area at the time.
 * It is strange that near the area where Foley sees several unidentified soldiers near the bus, there is a pickup truck with the twisted remains of a WWII-era M1919 Browning machinegun loaded in the back. It is possible that the pickup truck armed with a machinegun was used by local civilian resistance to defend themselves against the Russian forces.
 * If you fire at the unidentified soldiers near the bus before the whole scene plays out, Foley will still throw the flare at them, even though they are shooting at him.
 * Many of the buildings in this level and the next level have pictures of William Henry Harrison, the President who served the shortest term, after dying in only a month in office.
 * If you try to throw a grenade at the beginning of the level, it will say "No M2 Frag Grenades" just as in S.S.D.D.
 * An interesting thing to note is that before the EMP wave hits, the red dot is already down.
 * The aircraft on the street ahead that Cpl. Dunn comments on is a Boeing 777-200ER, which is a fly-by-wire aircraft. This explains why it was downed so quickly after the EMP hits.
 * It is unusual that Sgt. Foley is carrying an M4A1 magazine considering he is using a SCAR-H and the two weapons use different types of ammunition, as well as having magazines in different shapes. One explanation is that it could be a 5.56 SCAR-L magazine, which can fit into a M4A1.
 * As soon as you are released from the downed helicopter, turn left until you are on a grassy patch. If you quickly look up, a Little Bird will drop on you at an incredibly high speed. It seems to fall faster each time you spawn and run back to the same area.
 * If you (Sat1) don't look to the right as told, ISS Control will say "Sat1, rotate your view a little to the right, will ya?" And you only need a glance at the missile.
 * If you continue to not look eventually ISS Control will say there lines despite you not looking over at the missle.
 * The President's bunker door is unrealistically thin, and looks like it could easily be destroyed by explosives. The roof is also too thin; no way would a bunker for such a high-profile person be penetrated so easily by what appears to be either a mortar or Howtizer round.
 * There is a glitch when after Cpl. Dunn leaves the building after the little bird crashes blocking the way you came in, if you look to the left of the bus there is a police car that has not been destroyed by the EMP. This was most likely overlooked by Infinity Ward due to the fact that you most likely would not look towards that direction if you are trying to beat the level as fast as possible.
 * Just before meeting the runner, you can see the traffic lights are still blinking red, even though the EMP was supposed to destroy all electronics.
 * As with Game Over, there is a way to obtain three weapons. As the helicopters start falling, run to the area where the first helicopter crashes dangerously close to Dunn. If you maneuver around it carefully, you should be able to pick up an enemy weapon (Often an AK-47 or a FAL). Continue on as normal until you get to cover inside the building. When a deafening explosion goes off behind you, you gain max ammo in your M4 and you gain an M9, while also keeping your third weapon. Feel free to keep them for as long as you want and swap them out for other weapons.