A super pressure balloon is made polyethylene, a thin plastic material with roughly the thickness of a sandwich zip lock bag. When inflated, this balloon will be roughly 150 m in diameter. The balloon floats at 110,000 feet ( or about 23 miles). This is about three times the height of a commercial airplane, which typically flies at 30,000 to 40,000 ft or about 7.6 miles. The super pressure balloon has no open ducts so that once inflated, the helium cannot escape the balloon. The balloon is filled with enough helium to lift the flight train, including the balloon and the payload. As the balloon rises in the atmosphere, the air pressure on the outside decreases and the balloon expands. At 110,000 ft the helium is constrained by the size of the polyethylene envelope which keeps the balloon from expanding any further. From there it will remain at this float altitude until the flight is terminated. The mass of the air that is displaced by the balloon is equal to the mass of the balloon and payload, an example of Archimedes Principal. The balloon has a positive internal pressure during the day and at night, varying only by 0.0261 psi. The volume of air displaced and the float height are constant. This allows the balloon to support long duration missions at fixed altitude. The first test flight from Wanaka had a duration of 32 days and 5 hours. The 2016 mission's flight lasted 46 days and 20 hours. The NASA CSBF Super Pressure Balloon flight program has a goal of flights lasting upwards of 100 days. In comparison, the non-super pressured balloon flights average 24 to 48 hours. The balloon for the EUSO SPB mission is being made by Raven Aerostar at their facility in Sulfur Springs, Texas.
The balloon will be launched from Wanaka, New Zealand. From there, it is up to the winds with where it goes. In the two previous SPB flights done by NASA, one has gone west and one has gone east. It really just depends on the winds of the day. As soon as the balloon is launched, NASA cannot steer it, they are only able to terminate it.
Simply put, it will sink. One of the design requirements for designing the payload is for it to sink due to environmental regulations. If it were to land in the sea and float it could endager sea creatures and the possibility of recovering it is significantly low so it is not worth the risk.
Yes there is. During the flight there is a satelite link that transmits the data to a server in Palestine, Texas. The data is downloaded constantly but there is a slight delay betwen the detector taking data and the server recieving the data. This provides a back up of the data in case the payload is unable to be recovered.
This is an unmanned flight, meaning that there is no one who will be riding on the balloon.
You are not able to see cosmic rays directly with the naked eye however you are able to see the effects of cosmic ray airshowers. The aurora borelais, otherwise known as the northern lights, are caused when cosmic rays from the sun enter the earths' atmosphere.