That means much more fuel can be carried into orbit than could be carried on a single launch. Missions that send spacecraft with no crew to the outer planets often travel complex trajectories around the Sun.
They use what are called gravity assist manoeuvres to effectively slingshot around different planets to gain enough momentum to reach their target. This saves a lot of fuel, but can result in missions that take years to reach their destinations.
Clearly this is something humans would not want to do. Both Earth and Mars have almost circular orbits and a manoeuvre known as the Hohmann transfer is the most fuel-efficient way to travel between two planets.
Basically, without going into too much detail, this is where a spacecraft does a single burn into an elliptical transfer orbit from one planet to the other. A Hohmann transfer between Earth and Mars takes around days between eight and nine months and is only possible approximately every two years due to the different orbits around the Sun of Earth and Mars.
A spacecraft could reach Mars in a shorter time SpaceX is claiming six months but — you guessed it — it would cost more fuel to do it that way. A spacecraft entering Earth is able to use the drag generated by interaction with the atmosphere to slow down. Even though Bresnik will be returning with just two other crew members, the Soyuz will be a tight fit.
Size is just one of many differences between landing in a Space Shuttle and a Soyuz. One of the most notable differences, according to astronauts, happens during reentry. Reentry for a Space Shuttle is fairly smooth, and the wings allow for a landing similar to that of a glider.
Reentry for a Soyuz capsule, on the other hand, is often described as a series of car crashes. Of course, it was also the only one. There was still quite a bit of piloting to do, though, as he flew the nose gear precisely down to the runway at the proper speed; getting that maneuver wrong could have led to a violent slap-down that would have cracked the fuselage.
He kept our ,pound vehicle on the centerline as it hurtled down the runway at nearly mph, and I deployed the drag chute to slow us down. All the while a continuous stream of fire spewed from the back of the orbiter, where our rocket-fuel-powered hydraulic pumps vented their exhaust. I liken the experience of landing in a space shuttle to a nice, smooth Air Force landing.
If coming back to Earth in the shuttle is like riding an airliner, being in the Soyuz is like riding a bowling ball. The first noticeable difference was shortly after EI as we reentered the atmosphere. This time it occurred in daylight. While the shuttle had a cross-range of more than 1, miles, a capsule returning from orbit can typically turn only 50 miles to the left or right.
As we were zooming over Africa, we banked to the right, and when I looked out the hatch at the ground below, we were moving fast! It was so impressive that I scribbled a few unintelligible notes to myself on my kneeboard, trying to draw my fleeting view while scrunched up in that tiny capsule and bulky spacesuit. The actual EI phase was also quite a bit different.
First of all, the Soyuz separated into three parts with a giant bang minutes before EI: an empty orbital module, the descent module where we were, and an unmanned service module. After hitting the atmosphere, the external Soyuz heat blanket burned off.
I had never been in a flying vehicle that was literally ripping apart while I was flying it, but thankfully this was per design. The thought ' I hope this disintegration eventually stops ' did cross my mind, but there was nothing I could do in either case. There were constant banging and ripping noises as I watched pieces of the blanket and who knows what else fly by my window. Then came the parachute. It felt like we were going to die.
But, thanks to the briefing, Samantha Cristoforetti, my Italian crewmate, Anton Shkaplerov, my Russian crewmate and Soyuz commander, and I had a blast when the drogue chute came out. Next came the waiting, as we slowly descended the remaining few thousand feet to the Kazakh Steppe.
Just when things seemed to be smoothing out, the seat violently raised itself lifting about a foot up from the bottom of the spacecraft.
This allowed a shock-absorber device to cushion the impact a bit. Each crewmember has his own couch, form-fitted to his body; mine had been cast about two years prior, at the Energia factory near Moscow. During that procedure, you put on white long underwear to cover all of your skin and get lowered by a crane down into wet plaster. As the Russian technicians finish this seat, they manually carve out extra room above the top of your helmet area, and I used every bit of it.
On Earth I fit without a problem, but after days in space I had grown a few inches and the top of my head was butted up against the top of the seat liner.
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