Boeing’s Starliner capsule (CST-100), launched on an Atlas V rocket, has failed to reach its intended orbit. This mistake was blamed on the capsule burning too much fuel after it had separated from the rocket. It is unmanned and the error occurred when it was passing between the range of two satellites and was briefly out of contact with ground control. Boeing have said that, had the capsule been manned then this problem could have been avoided. It means that it will not be able to rendez-vous with the International Space Station (I.S.S.) which had been part of the original mission brief. It still has electrical power and some rocket fuel so the vehicle is due to return to Earth in the New Mexico desert in the next day or so.
The module should be able to transport seven astronauts to the I.S.S. or any future space stations. At the moment, US astronauts are taken into space on Russian Soyuz capsules.
The Boeing module sits on top of this amazing machine. The rocket consists of three stages. The first stage mixes the hydrocarbon fuel, kerosene, with liquid oxygen and produces about 4 million newtons of thrust. The smaller second stage (known as Centaur) is powered by liquid hydrogen and oxygen. For lifting heavier payloads like the CST-100 the Atlas V can also have up to three solid fuel booster rockets each adding 1.2 million newtons of additional thrust.
The main engine burns for a little over 4 minutes and then is followed by nearly 14 minutes of second stage burn. This can accelerate the vehicle to around 30,000 mph (13,400 m/s). The speed record for rockets is held by an Atlas V that reached 36,000 mph (16,000 m/s) by the time it left the Earth’s atmosphere. It then accelerated to 47,000 mph (21,000 m/s) in the vacuum of space.
The Atlas class of rocket has been in development since 1957. Looking through the Wikipedia page of its flights, it is noticeable how often things go wrong. It was brave of John Glenn to get on board in February 1962 for the first US manned flight into space. When you get to the page for more recent missions you can see how much more reliable the system has become.
Questions…
- Which force opposes the rocket’s attempt to leave the Earth?
- What two main waste gases are produced by the first stage of an Atlas V rocket?
- What single waste gas is produced by the second stage of the Atlas V?
- Why is liquid oxygen used instead of gaseous oxygen?
- At liftoff, roughly how many newtons of thrust does an Atlas V N22 rocket produce?
The name Starliner made me think of this great song by the band Culture from their album Two Sevens Clash. I listened to it over and again when I was in my last year at University.
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