We sent three suborbital sounding rockets
right into the auroras above Alaska on the evening of March 1 local time from the Poker Flat Research Range north of Fairbanks, Alaska.
Sounding rockets are suborbital rockets that
fly up in an arc and immediately come back down, with a total flight time
around 20 minutes.
Though these rockets don’t fly fast enough to
get into orbit around Earth, they still give us valuable information about the
sun, space, and even Earth itself. Sounding rockets’ low-cost access to space
is also ideal for testing instruments for future satellite missions.
Sounding rockets fly above most of Earth’s
atmosphere, allowing them to see certain types of light – like extreme
ultraviolet and X-rays – that don’t make it all the way to the ground because
they are absorbed by the atmosphere. These kinds of light give us a unique view
of the sun and processes in space.
Of these three rockets, two were part of the
Neutral Jets in Auroral Arcs mission, collecting data on winds influenced by
the electric fields related to auroras. Sounding rockets are the perfect
vehicle for this type of study, since they can fly directly through auroras –
which exist in a region of Earth’s upper atmosphere too high for scientific
balloons, but too low for satellites.
The third rocket that launched on March 1 was part
of the ISINGLASS mission (short for Ionospheric Structuring: In Situ and
Ground-based Low Altitude Studies). ISINGLASS included two rockets designed to
launch into two different types of auroras in order to collect detailed data on
their structure, with the hope of better understanding the processes that
create auroras. The initial ISINGLASS rocket launched a few weeks earlier, on Feb. 22, also from the Poker
Flat Research Range in Alaska.
Auroras are caused when charged particles
trapped in Earth’s vast magnetic field are sent raining down into the
atmosphere, usually triggered by events on the sun that propagate out into
Team members at the range had to wait until
conditions were just right until they could launch – including winds, weather,
and science conditions. Since these rockets were studying aurora, that means
they had to wait until the sky was lit up with the Northern Lights.
Regions near the North and South Pole are
best for studying the aurora, because the shape of Earth’s magnetic field
naturally funnels aurora-causing particles near the poles.
But launching sensitive instruments near the
Arctic Circle in the winter has its own unique challenges. For example, rockets
have to be insulated with foam or blankets every time they’re taken outside –
including while on the launch pad – because of the extremely low temperatures.
Would there be a scientific way to determine how far Team Rocket would need to blast off to disappear into the sky? – Requested by @jc-75
Prepare for trouble, and make it double! If you are part of the pokémon fandom, you probably know Jessie, James, and Meowth’s motto by heart. Equally famous, however, is the fact that Team Rocket “blasts off” a lot. Nearly once every episode, Team Rocket is hurled into the sky, disappearing in a tiny sparkle.
Things look smaller the farther away they are: that much everyone knows. The relationship is not linear, however: something that is twice as far away does not necessarily appear twice as small. The numbers are actually related through angles and trigonometry: sines, cosines, and tangents.
Because of that, for this problem we want to use angular distances. Angular distance is a measurement of how much of your field of vision something covers. A full circle is 360 degrees. A full moon, for example, has an angular diameter of about 0.5 degrees: it covers half a degree in the sky.
Angles can be divided up into smaller units. There are 60 arcminutes in one degree, and 60 arcseconds in one arcminute. The human eye has an angular resolution of 1 arcminute (0.02 degrees). That is the smallest thing we can see in the sky: If something covers less than 1 arcminute, or eye can no longer detect it and it effectively disappears from view, like Team Rocket fading into the sky.
So: how far away does Team Rocket have to be to cover less than 1 arcminute in angular distance? I can’t find any official heights for Jessie and James, so I will estimate 6′0″ (1.8 meters) as an upper limit. After that, it’s just about drawing triangles.
Using 1 arcminute as the angular distance and 1.8 m as the height, you can easily solve for distance. Team Rocket effectively disappears at a distance of 6188 meters (3.84 miles).
Angular resolution is dependent on the size of the eyeball, so pokémon with large eyes like Claydol or Froakie would be able to see Team Rocket farther away than that. But for humans, that’s how far Team Rocket needs to blast off to disappear.
Team Rocket blasts off at least 6188 meters (3.84 miles) away in order to disappear from view.
Yesterday (19 Feb 2017), the second stage of
Falcon 9 boosted a Dragon cargo capsule into orbit to deliver equipment to the International Space Station, and
the first stage flew back and touched down on solid ground. It was the 8th successful landing (out of total 13) for SpaceX.
Every success brings Elon Musk’s vision of a fully reusable rocket transport system (between Earth and Mars) closer.
The United Launch Alliance’s Atlas V rocket carrying the Orbital ATK Cygnus module rolls to Cape Canaveral Air Force Station’s Launch Pad 41 in this time-lapse video. The rollout is in preparation for the Orbital ATK CRS-7 mission to deliver supplies to the International Space Station.