If you saw a UFO over South Africa on Sunday, it was (probably) SpaceX’s improved Falcon 9 going into orbit. The commercial launch vehicle lifted off from Vandenberg Air Force Base, California at 9:00 AM CDT on a demonstration flight of the upgraded booster and a new engine cluster configuration.
Shown as a live video stream on the web, Sunday’s launch went almost without a hitch. One minute, 10 seconds after liftoff, the two-stage rocket broke the sound barrier and at about the two and a half minute mark, two of the first-stage engines shut down, followed shortly after by the remainder. Five seconds after main engine cutoff, the first and second stages separated. The second stage engine burned for 6 minutes, 17 seconds to put the payload into orbit.
On Twitter, SpaceX founder Elon Musk said, “Launch was good. All satellites deployed at the targeted insertion vectors.”
The launch vehicle was the Falcon 9 v 1.1, which is the replacement for the original Falcon 9. With a height of 68.4 m (224 ft), it’s significantly taller that the original Falcon’s 54.9 m (180 ft). It’s also heavier with a launch weight of 505,846 kg (1,115,200 lb) as opposed to 333,400 kg (735,000 lb). The Falcon 9 v 1.1 can put 13,150 kg (28,990 lb) into low Earth orbit over the original's 10,450 kg (23,040 lb) and can send 4,850 kg (10,690 lb) to geosynchronous orbit where the old Falcon 9 could only cope with 4,540 kg (10,010 lb).
At the heart of the Falcon v 1.1 is the new Merlin 1-D engine. Also developed by SpaceX, the throttleable, liquid-fueled engine generates 147,000 ft lb (654 kN) of thrust over the older Merlin 1-C’s 94,000 ft lb (420 kN). There are nine of these engines set in what SpaceX calls an “octaweb” arrangement. This is an “O” pattern” of eight engines in a ring around a single inboard engine, which provides streamlining and increases strength to withstand the Merlin 1-D’s greater thrust. It also makes the first stage more compatible with a reusable booster design and is easier to construct using robotics than the previous configuration.
Another first is the payload fairing. This aerodynamic nose cone is made of carbon fiber and an aluminum honeycomb core, and with a diameter of 17 ft (5.1 m) and a height of 42 ft (12.8 m), it's big enough to hold a bus. Previous Falcon 9 flights carried the Dragon spacecraft, which does not need a fairing at launch.
As part of this demonstration flight, the Falcon 9 carried the Canadian Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE) and three other satellites into low Earth orbit. CASSIOPE is a demonstrator for a new Canadian small satellite design using a common bus. It was joined by the Polar Orbiting Passive Atmospheric Calibration Spheres (POPACS), which is a privately funded CubeSat mission designed to measure the effects of solar flares on the upper atmosphere; the Drag & Atmospheric Neutral Density Explorer (DANDE), a student-built spherical spacecraft for studying atmospheric drag in the lower-thermosphere; and Cornell University’s CUSat, which is testing a new GPS algorithm for millimeter-level navigation.
There was one disappointing result from the launch. The Falcon 9 first stage is designed to eventually be able to land on its own back at the launch site. As part of developmental testing for this capability, SpaceX tried to relight the first stage engines, but things did not go to plan. According to Musk on Twitter, “Rocket booster relit twice (supersonic retro & landing), but spun up due to aero torque, so fuel centrifuged & we flamed out.”
Despite this, Musk remains confident, as he relates in a subsequent tweet: “Between this flight & Grasshopper tests, I think we now have all the pieces of the puzzle to bring the rocket back home.”
The SpaceX video below shows Sunday’s launch.
Source: SpaceX
How about using buoyancy by launching from the bottom of the ocean? The special air tanks would need to be near the top of the rocket because, contrary to a jet engine, buoyancy devices can impart a torque. The tanks would need to be pumped full of compressed gas and release it through overpressure valves during the ascent. The whole contraption would have to ride in a supercavitating bubble to reduce mechanical stress and increase maximum velocity.
I admit, it probably makes more sense to use the ocean on the way down for retarding reusable stages rather than using massive amounts of rocket fuel to do the same thing. Think of gannets using supercavitation while plunging into the see for fish.
But how can it land on its own back? And it's a cylinder, isn't it, so where exactly _is_ its back? I'm puzzled.